Agenda packet — Glendora City Council, January 24, 2023 (part 4 of 7)

These early settlers came together to start a community, as shops, blacksmiths, churches, and a few houses began to dot the landscape. They even opened a small schoolhouse on the old Dalton homestead, named the LaFetra School (City of Glendora 1999; Landers 2001; Price 2008).

In 1884, George Dexter Whitcomb a coal mining and manufacturing man from Chicago retired and moved to the Glendora area. Whitcomb bought two hundred acres from Harrison Fuller, John Bender, and several other pioneers of the area. Whitcomb became associated with John Cook and Merrick Reynolds who had substantial land claims and formed the Glendora Land Company to purchase land for a plat the town of Glendora. The name Glendora is a Item #8. Page 880
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combination of Mrs. Whitcomb’s name, Leadora, and the mountain glen view from the back of their family home (City of Glendora 1999; Lewis Publishing Co. 1889; Price 2008).

In 1885, the Atchison, Topeka & Santa Fe Railway Company was already building a line from Pasadena to San Bernardino, and on May 31 the first train on the new line arrived in Los Angeles, stopping at Glendora Station along the way. The tracks running through Glendora were first owned by the San Bernardino and Los Angeles Railway and the California Southern Railroad, both subsidiaries of the Atchison, Topeka and Santa Fe Railway. The original Glendora Station was little more than an old boxcar on a rail siding in 1887. By 1888, the official Victorian-style Glendora Station was opened, but the station was demolished in the 1950s and replaced with a concrete block building, which has also since been demolished. The railroad would go on to play an important role in the development of the citrus industry in Glendora. In 1907, the Pacific Electric Railway came to Glendora and the Great Bridge was built over the San Gabriel River. It was destroyed in 1938 by the great flood of San Gabriel and was subsequently replaced with a single-track steel structure (Landers 2001; Price 2008, 2012).

On November 13, 1911, the City of Glendora was officially incorporated, and in 1915, the Glendora Water Company was purchased by the City (Figure 4). In 1921 Glendora opened its “auto camp” on Michigan Avenue, offering a great alternative to expensive hotels that provided visitors with free stoves, a covered kitchen, and running water.

The building boom in Glendora culminated in 1922 with construction of City Hall on Foothill Boulevard just east of Michigan Avenue (Price 2008).

Figure 4. Birds Eye View of Glendora, ca. 1910 (LAPL)
In 1923 the Glendora Fruit Exchange was established when the Glendora Citrus Association and the Glendora Heights Orange and Lemon Growers Association joined forces to build their own packing house. Eventually, Glendora was producing over one million boxes of fruit per year and had numerous packing houses to meet the demand. The city often appeared to be on fire at night with the orange flames from all of the oil smudge pots used to keep the citrus groves warm during the frost. A review of Sanborn Fire Insurance maps from the late 1920s show that the Glendora Mutual Orange Association was located within the proposed project APE. This company marketed under the Azusa-Covina-Glendora Fruit Exchange, which in 1927 shipped 1,117 cars of oranges and 30 cars of lemons for a total return of $1,176,000. The citrus boom carried into the 1930s and continued to grow (Los Angeles Times 1927). At the citrus industry’s peak in 1947, Glendora had more than 5,000 acres of oranges and lemon Item #8. Page 881
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groves and six packing houses, which produced approximately 78,000 tons of citrus per year, worth between $4 and $8 million. A serious tree disease, bluntly known as “quick-decline disease,” struck the area in the 1940s– 1950s and the industry began to suffer. The disease, in combination with rising costs of labor and water, may well have marked the beginning of the end of the booming Glendora citrus industry (Derbeken 1987; Landers 2001; LAT 1927)
During World War II, Glendora was host to a Civilian Public Service camp for conscientious objectors, located in Big Dalton Canyon. The conscientious objectors, their family, or sponsoring religious affiliation paid a monthly fine of $35 (equivalent to $488 in 2019) and the objectors worked as medical study subjects and on civilian infrastructure projects, rather than be drafted by the selective service act. Men who did not report to the draft had to report to a conscientious objector’s camps or be imprisoned and potentially sent to “punishment camps”. Conscientious objectors in the Glendora Camp were not well treated or paid for their work. In spring 1946, the Glendora camp conscientious objectors lead a series of strikes in response to two workers being sent to a punishment camp without charges, hearings, or appeals, as well as being forced to perform unpaid labor, denial of accident compensation, adequate medical care and physical abuse from supervisors. The 1946 strike began in Glendora and spread to other camps throughout the nation. Though World War II ended in 1945, camp continued to hold objectors until December 1946 (Glendora Strikers 1946; LAT 1941; SBCS 1946) In 1945, veterans began to return from World War II with their sights set on starting a family and purchasing a home. As nearby areas such as Pasadena, Temple City, Arcadia, and Monrovia began to see drastic increases in property values, residential developers began to consider Glendora a better value for new home construction.

Residential subdivisions began to appear north of the central downtown Glendora are in the 1953, Along the main north-south thoroughfare, North Glendora Ave, residential subdivision begin to replace the orchards and fields north of E. Leodora Avenue in the 1950s, and begin to be developed north of Sierra Madre Avenue by the 1960s. The town boundary also edges west, closer to the proposed project APE and the nearest town of Azusa, replacing agricultural fields, orchards between 1965 and 1975. Most of the agricultural lands in the foothills north of Glendora disappear between 1972 and 1977. However, the agricultural lands between Glendora and Azusa to the west persist until roughly 2005-2009, when a large-scale residential subdivision fills the entirety of the space north of the 210 Freeway, south of the San Gabriel Mountains foothills, east of North Pasadena Avenue in Azusa, and west of North Yucca Ridge Road in Glendora (Glendora Chamber of Commerce 2014; NETR 2019).

3.3 Project Area History
This section summarizes the history of the residential development of 950 Silent Ranch Drive (APN: 8684-045- 004). Unrelated to residential development, this section also summarizes the historic context for the USDA Forest Service and Los Angeles County Flood Control District dams and flood control channel on the property and Metropolitan Water District Upper Feeder pipeline, which transects the proposed project APE.

Residential Development
Rancho Los Alisos (1907-1953)
Judge Charles Silent was a lawyer, judge, and a prominent real estate speculator in Los Angeles. Silent moved to Los Angeles in 1885, and made connections while representing wealthy landowners and speculators during the real estate boom of the 1880s. Silent also made key real estate investments and bought large tracts of land along Item #8. Page 882
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the coast southwest of Los Angeles, developing the communities of Inglewood and Redondo Beach. Silent lived near the present-day University of Southern California campus, and in 1900, he created the gated subdivision of Chester Place around his home. In 1907, Judge Charles Silent purchased 110 acres just north of the town of Glendora from one of his clients, P. Shorey, though he remained in Los Angeles for a few years after the purchase.

Silent continued to be engaged in both Los Angeles and Glendora, proving an influential voice in the construction of a scenic highway from Redlands to the sea, now Foothill Boulevard. (LAT 1907a, 1907b; Price 2008).

After a family death, Silent moved to Glendora permanently in 1908. Silent retired from his law practice and devoted himself to the development of his Glendora property, turning it into a landscaped park, with experimental orchards where he could engage in horticultural plant, fruit tree, and flower production. Silent hired Henry and Charles Greene, well known Arts and Crafts Era architects, to design the ranch house at Rancho Los Alisos (Figure 5). While the Arts & Crafts-style Greene & Green bungalow design apparently never came to fruition, the houses that were built along the floor plan were humble canvas and wood structures with palm thatch-clad roofs. (Argus 1910; Greene & Green Architects 1908; Price 2008).

Figure 5. Floor plan: Sheet no. 2 May 22, 1908. "Walls battered as directed". (NYDA.1960.001.03529, Greene & Greene Architectural Records & Paper Collections, Avery Architectural & Fine Arts Library) Silent became involved with the California Avocado Association and eventually became a director of the organization, growing lemons and varieties of avocados at Rancho Los Alisos. Silent engaged the local pomological societies and opened his property to the public on Sundays so that residents of Glendora could enjoy his gardens and grounds. During this period, Silent’s property consists of a grouping of rancho-style buildings with the appearance of palm-leaved thatched roofing, and also developed rock-lined bricks paths, elaborate flower and palm Item #8. Page 883
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tree plantings, viewing platforms, fountains, and a fishing basin where Silent stocked black bass (Figures 6, 7).

According to a newspaper feature about the property, Silent irrigated his vast property using spring water from further up the mountain. Silent supposedly tunneled north to the springs, and brought water through a series of underground reservoirs, and pipelines to his property. Once there, Silent irrigated his plants but also created “aa series of reservoirs that are connected here and there with artistic stone grottos and scenes of flowing and falling streams” (Argus 1910: 2). After Silent’s death in 1918, and his wife’s death in 1921, the property remained unused, and cared for by a small caretaker staff. The Silent estate eventually sold portions of the ranch to real estate developers. Though the original house was demolished between 1964 and 1968, and a new residence constructed on the location, some of these plantings, water conveyance systems, and rock-lined landscape features remain (Argus 1910, 1921; LAT 1918; Price 2008; UCSB 2019).

Figure 6. Postcard of Rancho Los Alisos ranch house building group. (Silent Ranch subject files, Glendora Historical Society)
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Figure 7. View to main buildings of Rancho Los Alisos, looking southwest, c 1910 (Oversized photos, Glendora Historical Society)
Camp Aventura (1953-1974)
In 1953, the Los Angeles Council of Girl Scouts and Girl Scouts of America began making formal inquiries about purchasing 295 acres for a camp in Glendora, including the former Silent Ranch Property. Beginning as early as 1953, a Master Plan was in the works for the camp, which planned to develop 12 unit sites on the property. The Los Angeles Council of Girl Scouts member troops raised the funds for the camp through yearly cookie drives and other fund raising efforts, and eventually purchased 295 acres of the former Silent Ranch estate. In October 1955, Camp Aventura was officially dedicated and opened. By 1956, four buildings and 12 tent pads were present at the site. The area had been cleared of orchard trees and in 1956, Girl Scouts planted trees and other vegetation around the new camp. In 1959, the Los Angeles Council of Girl Scouts made its final payment on Camp Aventura in Glendora, owning the property outright. The camp continued to operate until at least 1971, and in 1974, the Los Angeles Council of Girl Scouts sold the Camp property to George and Jean Deukmejian1. The Deukmejians demolished the remaining Girl Scout buildings on the property, but donated a 30-acre parcel to the City of Glendora to use as dedicated open space (LAT 1953, 1956, 1958, 1959; Leagle 2019; Valley News 1956; UCSB 2019).

According to legal documentation:

The donated property consists of 28.93 acres, of which 0.29 acres are subject to a Flood Control District easement, leaving a net area of 28.64 acres. The property has an "L" shape measuring 1,650 feet long and a width of 1,320 feet along the northern boundary and a width along the irregular southern boundary of 440 feet. The parcel is located about 0.25 miles north of Palm Drive and about 0.25 miles west of Grand Avenue, if it were extended which it had not been at the time of trial (George Deukmejian and Jean Deukmejian v. Commissioner 1981). 1 George Deukmejian (b. 1920- d. 1985) of Glendora was cousin to former State Senator and Governor George Deukmejian (b. 1928- d. 2018); however, former Governor Deukmejian never resided in Glendora.

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Silent Ranch Estates Residential Subdivision (1974- present) George Deukmeijian first applies for a demolition permit for the Girl Scout Camp in 1974. Deukmejian began building a new residence at the site of the former Rancho Los Alisos house in 1976 and it was completed by 1980.

By 1981, the property also had a pool house, pool, and landscaped lawns, and small immature orchard northwest of the building. In 1982, Deukmejian’s company, Deukmejian Enterprises, began redeveloping the surrounding property into a residential subdivision called Silent Ranch Estates with 15 lots. Lots were prepared and custombuilt homes offered beginning in 1984, and later the same year, City of Glendora allowed it to become a private, gated community. By 2003, all 15 lots were filled (LAT 1984a, 1984b, 1985; UCSB 2019).

Water Infrastructure Development
A small, subterranean segment of the Metropolitan Water District of Southern California (MWD) Upper Feeder pipeline is present in the proposed project APE as a tunnel, historically called Monrovia No. 1. The segment is entirely below ground and extends roughly 1,150 feet within the proposed project APE. The total length of the Monrovia No. 1 tunnel is 7,868 feet (Weymouth 1939). In three of the small riparian canyons in the proposed project APE, there are crib dams and one flood control channel. In 1970 the US Forest Service, City of Glendora, Los Angeles County Flood Control District, and Army Corps of Engineers, responded to a 1968 fire and 1969 mudslide in the City of Glendora by installing these crib dams to abate future flood and mudslide damages.

Metropolitan Water District: Upper Feeder Aqueduct (1939-present) The Metropolitan Water District of Southern California MWD was established in 1928, as a result of the Metropolitan Water Act. With this act, the State authorized the new agency to build an aqueduct 242 miles to bring Colorado River water to supplement Los Angeles Department of Water and Power sources for City of Los Angeles, and to provide municipal water to thirteen cities in the Los Angeles metropolitan area not served by LADWP. In 1931, the Colorado River Aqueduct project was funded by a bond measure approved by the thirteen cities: Anaheim, Beverly Hills, Burbank, Compton, Fullerton, Glendale, Long Beach, Los Angeles, Pasadena, San Marino, Santa Ana, Santa Monica, and Torrance. MWD’s Colorado River Aqueduct construction project, which lasted nearly 10 years, erected four dams, five pumping plants, 92 miles of tunnels, 63 miles of concrete lined canals, 55 miles of concrete conduit, and 29 miles of siphon from Lake Havasu to Lake Matthews in Riverside. Once in the reservoir at Lake Matthews, water was dispensed to the member cities through the distribution system. Both the aqueduct and distribution system were some of the largest public works projects in southern California during the Great Depression (Desert Sun 1938; LAT 1934; Weymouth 1939).

Concurrent to the erection of the 242-mile aqueduct was the distribution system that lead from the aqueduct terminus to each of the participating cities. The distribution system consisted of the Morris Dam and Reservoir, 16 miles of tunnel, and 134 miles of pipelines to carry water to each of the thirteen cities (Figure 8). Two portions of this distribution feeder system are located in the proposed project APE. North of the APE, the Morris Dam was erected between 1932 and 1934 in the San Gabriel River Basin. It was originally owned by the City of Pasadena, but sold in 1935 to MWD. The other portion is the Upper Feeder distribution line, a 65-mile distribution line extending from Lake Matthews to the San Rafael Tunnel. The upper feeder consisted of sections of underground 10-foot diameter tunnel lined with concrete, and large diameter precast concrete or welded steel plate pipes. In 1935, orchard owners north of Glendora, Claremont, La Verne, Pomona, and San Dimas conferred with MWD and attempted to negotiate for surplus water in exchange for allowing the pipeline through their lands. In 1936, a new Item #8. Page 886
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MWD water district inducted the cities of Ontario, Upland, Claremont, San Dimas, Glendora, Pomona, and La Verne (Argus 1935; Creason 2015; Hinds 1935; SBSC 1936a; Weymouth 1939; WDPJ 1936).

Figure 8. Colorado River Aqueduct Map, The Metropolitan Water District of Southern California. (Special Collections, Honnold Mudd Library, Claremont Colleges Library system) Construction of a 30-mile section of the Upper Feeder pipeline began in 1936 near the Lake Matthews Reservoir, and extended north to Fontana then west to just below Morris Dam Reservoir north of Glendora in the Angeles National Forest. From Morris Reservoir, the feeder continued west in a separate segment through the Monrovia No. 3 through 4 tunnels to the San Rafael Tunnel, to Glendale. In Glendora, the Upper Feeder pipeline stayed at the base of the San Gabriel Range foothills, before crossing diagonally through the foothills northwest towards Morris Dam. A right-of-way was obtained in 1935 for the section through the Silent Estate. This location was chosen partly to avoid costly purchases of rights-of-way, which would be needed in densely settled urban areas. The Silent Ranch Estate right of way was for part of Monrovia No. 1, a tunnel extending 7,868 feet from east portal to west portal, exiting above the San Gabriel River canyon. The tunnel work was completed by West Construction Company in February 1937. Construction of the Upper Feeder pipeline as a whole was interrupted by the major storm and subsequent flood damage in February 1938; however, work on the feeder was completed later that year. In 1939, the distribution system was connected to the Lake Matthews Dam but the main Colorado River Aqueduct was not completed until 1941. In June 1941, the aqueduct and distribution system finally went into operation and on June 20, 1941, water finally reached the City of Pasadena (Argus 1935; Creason 2015; Hinds 1935; LAT 1936; SBSC 1936a, 1936b; Weymouth 1939; WDPJ 1936).

In 1963, MWD announced a second feeder, called the Foothill Feeder, which could carry double the capacity of the original Upper Feeder, and bring Feather River water from Northern California via Castaic, through the foothill cities to San Bernardino. A tunnel, bypassing all of Glendora was announced in 1965, and would consist of a 6.5-mile concrete lined tunnel between San Gabriel Canyon and San Dimas (Figure 9). The contract for tunnel construction went to J.F. Shea Co., and blasting was completed by 1968. Tunnel Construction was scheduled for completion in 1969; however, litigation surrounding eminent domain takings by MWD went to the California Courts (Pasadena Independent 1964; SBCS 1963, 1965; Lauten 1970; LAT 1968).

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Figure 9. Glendora Tunnel section of the Foothill Feeder, 1965. (Los Angeles Herald Examiner Photo Collection, Los Angeles Public Library)
Los Angeles County Flood Control District and Forest Service Crib Dams (circa 1969-present) In 1968, a large wildfire in the foothills north of Glendora and Azusa burned 20,000 acres and decimated the underbrush and trees. The following January through March 1969, Glendora experienced heavy rains which led to flooding, devastating mudslides, and cascading boulders damaging homes and schools. Mudslides were especially damaging along Rainbow Drive, just two blocks east of Grand Avenue. Glendora sought relief and received $1.5 million in federal aid. One of the first projects to go through was the $340,000 debris control dam and basin just west of the proposed project APE in Hook Canyon, started in 1969. In spring 1970, City of Glendora, US Army Corps of Engineers, Los Angeles County Flood Control District (LACFCD), and the USDA Forest Service (USFS) began constructing 45 concrete crib dams in 15 canyons north of Glendora (Figure 10). The purpose of the crib dams was to allow debris and soil to accumulate behind the dams while allowing water through. Still more erosion control measures were taken by instating planting programs, and seeding areas of then 1968 burn scar. These efforts were rewarded in 1974 (LAT 1969a, 1969b, 1969c, 1970; Pasadena Independent 1968; USFS 1975).

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Figure 10. USFS employees constructing a concrete crib dam north of Glendora. (Los Angeles Times 1970)

3.4 Associated Engineer: Robert Bernard Diemer
(1888-1966)
R.B. Diemer was born in 1888 in Palmyra Missouri, and graduated from the University of Missouri with a Bachelor’s of Science in engineering at 23. Like many young engineers who graduated in the 1910s, Diemer began his career with the Reclamation Service (later Bureau of Reclamation), working on the North Platte Project (1903-1927), an irrigation project in Wyoming and Nebraska. In 1929, he left the Reclamation Service to work for the newly formed Metropolitan Water District (MWD), with other former Reclamation Service engineer Frank E. Weymouth. In 1930, Diemer became the distribution division engineer on MWD’s Colorado River Aqueduct project, responsible for all 150+ miles of distribution system west of Lake Matthews. Diemer remained in career at the MWD, and ion 1950 became assistant general manager. In 1952, he became MWD’s general manager and chief engineer and served in this position until he retired in 1961 (Hager 2015).

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3.5 Associated People: Judge Charles Silent (1842-1918) Charles K. Silent was born in 1842 in Prussia, but emigrated in 1848 to Columbus Ohio with his family due to the Revolutions of 1848. In 1856, at 14 Silent left home for New York and then onto a ship for San Francisco. Silent earned a teacher’s certificate by age 17 and worked as a teacher for several years before enrolling in University of the Pacific in 1862. He married Emma Daniel in 1864 and had three children before her death in 1870. Silent passed the California bar exam in 1868 and became partner to San Jose law firm of Moore, Laine & Silent. He remarried Mary Tantau in 1874 and developed connections in law and to the railroad industry. In 1878, President Rutherford B. Hayes appointed Silent as an associate justice of the Supreme Court of Arizona, however, Silent continued financial interests in railroads in mining during his tenure and in 1880 was investigated by the U.S.

Attorney general for his conflict of interest, and soon after the investigation, resigned from the court and returned to practicing law. Silent grew wealthy from his law practice in Tuscon but due to declining health, relocated to Los Angeles California in 1885 (LAT 1918; SFE 1878; Spitzzeri 2019).

In California, Silent joined W.P. Wade and W.F Fitzgerald in a law practice and continued serving wealthy clients in the metropolitan area, while simultaneously investing in the booming Southern California real estate. Silent joined many other wealthy Los Angeles elite in forming real estate companies such as Centinela-Inglewood Land Company (1887), and creating coastal towns such as Redondo Beach and Inglewood, and investing heavily in Azusa, Redlands, and the Foothill Boulevard road. Later he formed the firm Houghton, Silent, and Campbell with men he met through Wade and Fitzgerald’s connections. Silent moved into Nathan Vail’s mansion and formed the gated subdivision called Chester Place in 1899, creating a private park just southwest of the metropolitan center. Silent also practiced horticulture as a hobby, and perhaps as a result of this hobby and his multitude of connections to wealthy Los Angeles personalities and government officials, he was appointed to the head of the Los Angeles Parks Commission. There he worked on remodeling Pershing Square and Elysian Park, and secured Griffith Park from Colonel Griffith J. Griffith (LAT 1918; Spitzzeri 2019).

In 1907, one of Silent’s children died, and Silent responded by withdrawing from his legal practice and purchasing a large tract of land in Glendora from P. Shorey, which he would call Rancho Los Alisos. Silent had a home built in Glendora and effectively retired there by 1910. Silent remained active in pomological societies, horticultural societies, and hobby groups in Glendora, raising avocados, oranges, and lemons in addition to several exotic species. He also opened his Rancho Los Alisos property as a public park to Glendorans on Sundays. Silent died in 1918 leaving his wife and remaining four children (LAT 1918; Spitzzeri 2019).

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4 Historic Resources Survey

4.1 Methods
A pedestrian survey of the proposed project APE was conducted on August 1, 2019, for historic age built environment resources. During the survey, all buildings and structures within the proposed project APE constructed over 45 years ago were surveyed and recorded. All accessible portions of properties were also intensively surveyed for archaeological resources. The built environment component of the survey entailed documenting each building with notes and photographs, specifically noting character-defining features, spatial relationships, and any observed alterations. The survey area was photographed using a digital camera. All field notes, photographs, and records related to the current study are on file at the Dudek Pasadena, California, office.

4.2 Results
The proposed project APE encompasses approximately 27 acres, northwest of the intersection of W. Palm Drive and Grand Avenue in the City of Glendora. The survey of the proposed project APE was positive for 9 structures associated with Rancho Los Alisos (1908-1953), one building associated with Camp Aventura (1953-1973), three USFS and LACFCD crib dams and one channel (1970), and one above ground structure and the Monrovia No. 1 tunnel which are components of a larger water infrastructure system, the MWD Upper Feeder pipeline (c. 1936- 1939). These individual components have been categorized as three (3) resources that have been evaluated for historical significance as part of this project. Result for these resources are summarized below in Table 3. California Department of Parks and Recreation (DPR) Series 523 Forms were prepared for all built environment resources and are provided in Appendix C.

Table 3. Built Environment: Summary of Findings for buildings and structures in the Proposed Project APE
Resource name Property Type Year built
Applicable
Criteria CHRS Status Code
Rancho Los Alisos/
Camp Aventura
Structures: Landscape
architecture
Building: women’s
property; community
center/social hall
c. 1907/
c. 1955
n/a 6Z: Found ineligible for NR, CR or Local designation through survey evaluation.

USFS/LACFCD Crib
dams and channel
Structure: dams and water
conveyance system
(channel)
1970 n/a 6Z: Found ineligible for NR, CR or Local designation through survey evaluation.

Monrovia No. 1 tunnel
and hatch (component
of MWD Upper Feeder
pipeline)
Structure: water
conveyance system (tunnel,
hatch)
c. 1937 A/1/1 3D: appears eligible for NR as a contributor to a NR eligible district through survey evaluation
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5 Significance Evaluations
The following significance evaluations consider NRHP, CRHR, and City significance criteria and integrity requirements. For a property to be listed in or determined eligible for listing in the NRHP, it must be demonstrated to possess integrity and to meet at least one of four criteria. The CRHR was designed to reflect the same criteria and integrity as those identified for the NRHP. Therefore, the NRHP and CRHR significance evaluations are presented together.

5.1 Rancho Los Alisos/Camp Aventura Buildings
and Structures
Rancho Los Alisos/Silent Ranch and Camp Aventura occupy the same address and parcel, and are part of the same chain of ownership. Rancho Los Alisos was purchased in 1907 and developed beginning in 1908. The original house for Rancho Los Alisos was demolished between 1964 and 1968. The modern house of the property was built in 1980 and therefore not eligible for evaluation. Components of the Rancho Los Alisos grounds, such as the rocklined structures, constructed rock water features, and Black Bass Pool were constructed between 1908 and 1910 and are associated with the original period of development. Camp Aventura was purchased in 1953 and developed between 1953 and 1958. The camp was abandoned in 1971 and most camp buildings were demolished when it was sold in 1974. One feature of Camp Aventura remains: a bathroom/washhouse.

Rancho Los Alisos: Rock-lined road and bench feature
This road feature is located east and southeast of the 950 Silent Ranch Avenue house, and the bench feature is located southeast of the house. The rock-lined road feature is visible in photographs dating to 1910, and was developed between 1908 and 1910. The roadbed itself is unpaved, compacted dirt, but the rock retaining wall runs the length of the “uphill” side of the road and is constructed of concrete, faced with semi-coursed, locally sourced, dark gray stone. The bench is integrated directly into the wall and is also constructed of concrete and stone. Total bench height is roughly 3 feet, level with the retaining wall height and the bench seat height roughly 2 feet above the road surface. The width of the bench appears to be 3’6”-4’ with flared sides (Figure 11 and 12).

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Figure 11. Left: Rock wall and bench feature (IMG_4041); Right: 1910 photo of rock lined road and bench (Glendora Historical Society)
Figure 12. Another segment of rock-line road (IMG 4003) Rancho Los Alisos: Black Bass Pool
This pool feature is located northwest of 950 Silent ranch Drive house, long a ridgeline, immediately north of a mature lemon grove. The pool feature is visible in photographs dating to 1910, was featured in a newspaper article from 1911 describing its function, and was developed between 1908 and 1910. The pool feature extends at least ten feet below the rim. The pool rim rises roughly 1’6” above ground level. The pool is circular and has an approximate diameter of 25 feet. In the center of the pool is a burned metal and wood post, capped with a metal hood. The pool is constructed of concrete reinforced with metal mesh, the face of which is badly spalling in some places. Around the rim of the pool is a wood ring, which still contains metal fixtures for the gate feature which has been lost. A metal ladder provides access to the pool interior (Figure 13 and 14). The entire feature has been burned and the pool is partially filled with burned debris.

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Figure 13. Left: concrete pool, looking southeast (IMG_4054); Right: 1910 photo of bass pool (Glendora Historical Society)
Figure 14. Profile view of pool feature wall (IMG 1350) Item #8. Page 896
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Rancho Los Alisos: Constructed Rock “cave”, wall, steps, and water pool features The constructed rock cave feature, wall, steps, and pools are located immediately northwest of the black bass pool on the ridge above (northwest of) the house. The rock cave is constructed concrete faced with semi-coursed, locally sourced, dark grayish red stone. Over the arch of the entrance to the “cave” the rocks are arranged in an arch, with a keystone, and two 2-3 foot tall rock walls slope away from it (Figure 15). The opening itself is roughly 2 feet wide by 3 feet tall. Downhill of and connected to the cave by a continuous low rock-faced wall are at least two circular shallow rock-lined concrete pools, which produce a cascade effect downhill towards the black bass pool. Uphill of the cave is a 4-foot high rock faced concrete retaining wall. A set of 10 narrow stairs lead to the uphill area above the wall, and are also constructed of concrete and local dark gray-red stone (Figure 16).

Figure 15. Entrance to rock “cave” showing rock walls sloping away, view to west (IMG_4051)

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Figure 16. Stairs and retaining wall immediately right (northwest) of cave (IMG_1377) Rancho Los Alisos: Constructed Rock Fountain
The constructed rock fountain feature and pools is located northwest of the black bass pool on the ridge above (northwest of) the house, and southeast of the constructed rock cave. The constructed rock fountain is constructed concrete faced with semi-coursed, locally sourced, dark grayish-red stone (Figure 17). There is a smoothed, concrete, tool formed basin below the upper pour spout, forming the drinking fountain, which is roughly 2 feet x 1’6” in diameter and oval shaped. The fountain basin portion is roughly 3 feet above current ground surface and is obscured by brush.

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Figure 17. Left: view of steps looking northeast (IMG_1357); Right: 1910 postcard of fountain pavilion. (Glendora Historical Society)
Rancho Los Alisos: Stone Stairs to Dining Pavilion
Stone stair feature is located due north of the 950 Silent Ranch Drive house. The stair feature is visible in photographs dating to 1910, and was developed between 1908 and 1910. The feature consists of a set of windowing, narrow concrete construction, stone-faced steps, approximately 8 inches high, 8 inches tread, and roughly 2 feet wide, with a rock and concrete border to each side. The stair is banked into a steep hillside just north of the house and extends downhill roughly 15 feet below the driveway north of the house. (Figure 18 and 19).

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Figure 18. Left: view of steps looking northeast (IMG_2394); Right: 1910 postcard of steps leading to earthen pavilion. (Glendora Historical Society)
Figure 19. View of steps looking south (IMG 4006)
Camp Aventura: Restroom Building
Restroom building is a one-story, Mid-Century Modern-styled building constructed in circa 1955-1956, located northeast and immediately downhill from the 950 N. Silent Ranch Drive property and driveway (Figure 20). The building is one-story and a simple rectangle in plan, with the east portion enclosed for a three-stall restroom and privacy screen, and the west portion an open-air wash area. The building rests on a concrete slab foundation. It features a flat roof with wide overhang and wide, angled fascia board with open eaves, and is supported by wood posts and the restroom stall enclosed space. The roof is clad with rolled composition roofing and flashed with Item #8. Page 900
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aluminum-finish metal around the edges. The wall construction of the restroom stalls is wood stud clad with both board-and batten on the south and east elevation, and plywood on the west elevation. Along the north elevation there was a board and batten privacy wall in front of the stall doors, however, doors and privacy wall have been removed. Fixtures are still present at this building including an enameled double sink and three metal pit toilet fixtures. Along the rear (south) elevation, against the hillside, 2”x4” boards are nailed to the building exterior and support posts to provide pipe and wood board storage.

Figure 20. Main and west elevations of restroom building, view to southeast (IMG_4010) Identified Alterations
Dudek attained all available permits pertaining to the proposed project APE through the City of Glendora Building Department’s eTRAKit online permitting system on August 14, 2019. The permits date from 1975 through present, which are summarized below:
• 1947: Permit for house and attached garage at 575 W. Palm Drive • 1950: Permit for adding Bathroom to main house at 19153 E Sierra Madre; issued to Rancho Los Alisos • 1953: Plumbing permit for adding bathroom; sewer connection and septic tank to 19153 E Sierra Madre/935 N. Silent Ranch Drive; issued to Girl Scouts
• 1954: Permit for new roof cover for 13’ x 26’ reservoir; issued to Girl Scouts • 1955: Permit for building alterations 19153 E Sierra Madre/935 N. Silent Ranch Drive; issued to Girl Scouts
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• 1955: Plumbing permit for 3 toilets, 2 showers, 3 lavatory wash basins, 3 kitchen sinks and 2 gas outlets to 19153 E Sierra Madre/935 N. Silent Ranch Drive; issued to Girl Scout Camp (likely for fixtures in restroom building)
• 1955: Building Permit for “Unit Toilet Shelter” Building, Architect Paul R. Hunter, Contractor J. Lonnie Crumpler to 19153 E Sierra Madre/935 N. Silent Ranch Drive; issued to Girl Scout Camp (possibly the restroom building)
• 1955: Building Permit for “Public Sanitary Unit” 8’ x 12’ Building, Architect Paul R. Hunter, Contractor J.

Lonnie Crumpler to 19153 E Sierra Madre/935 N. Silent Ranch Drive; issued to Girl Scout Camp • 1955: Building Permit for “Unit Wash Shelter” Building, Architect Paul R. Hunter, Contractor J. Lonnie Crumpler to 19153 E Sierra Madre/935 N. Silent Ranch Drive; issued to Girl Scout Camp • 1955: Permit for new roof to 40’ reservoir; issued to Girl Scout Camp • 1955: Permit for new roof to 80’ reservoir; issued to Girl Scout Camp Glendora • 1955: Permit for Dormitory and Kitchen Building; Architect Paul R. Hunter, Contractor J. Lonnie Crumpler to 19153 E Sierra Madre/935 N. Silent Ranch Drive; issued to L.A. Girl Scouts • 1956: Permit for “Unit Wash Shelter” Building, Architect Paul R. Hunter, Contractor J. Lonnie Crumpler to 19153 E Sierra Madre/935 N. Silent Ranch Drive; issued to L.A. Girl Scouts • 1956: Permit for “Unit Toilet Shelter” Building, Architect Paul R. Hunter, Contractor J. Lonnie Crumpler to 19153 E Sierra Madre/935 N. Silent Ranch Drive; issued to L.A. Girl Scouts (possibly the restroom building) • 1959: Permit for 20‘ x 30’ “Shelter – Orange Camp”; Architect Tryon & Foy, Contractor Wendell Turner to 7755 N Grand Avenue; issued to L.A. Council Girl Scouts • 1959: Permit for 20‘ x 30’ “Shelter – Lemon Camp”; Architect Tryon & Foy, Contractor Wendell Turner to 7755 N Grand Avenue; issued to L.A. Council Girl Scouts • 1959: Permit for 20‘ x 30’ “Shelter – Lime Camp”; Architect Tryon & Foy, Contractor Wendell Turner for 7755 N Grand Avenue; issued to L.A. Council Girl Scouts • 1959: Permit for 20‘ x 42’4” “Handicraft House”; Architect Tryon & Foy, Contractor Wendell Turner for 7755 N Grand Avenue; issued to L.A. Council Girl Scouts
• 1959: Permit for 18’6”‘ x 42’4” “Latrine”; Architect Tryon & Foy, Contractor Wendell Turner for 7755 N Grand Avenue; issued to L.A. Council Girl Scouts
• 1959: Permit for 20‘ x 48’4” “Bath House” with 4 sinks, 2 showers, 10 toilet stalls, water heater and gas hookup; Architect Tryon & Foy, Contractor Wendell Turner for7755 N Grand Avenue; issued to L.A. Council Girl Scouts
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• 1959: Permit for Public Swim Pool, Standard Plan #16472; Architect W. Taggert, Contractor Paddock Pools, for 7755 N Grand Avenue; issued to Girl Scouts of USA
• 1963: Permit for 1 story, single-family 1142 s.f. “Caretakers House”; Architect Tryon & Foy, Contractor Colletta and Edgely for 7755 N Grand Avenue; issued to Girl Scouts of USA • 1963: Permit for 1 story, 3000s.f. “Dining Hall and Kitchen”; Architect Tryon & Foy, for 7755 N Grand Avenue; issued to Girl Scouts of USA
• 1973: Permit to demolish 5 “camping structures”; contractor U.S. Navy Seabees, for 905 N. Grand Street, Glendora; issued to Angeles Girl Scout Council
• 1974: Permit to demolish “2 buildings, one bathhouse and misc. structures”; issued to George Deukmejian • 1975: Permit for new 6200 sf house at 950 N Silent Ranch Drive; Architect: David Hyen Associates; issued to George Deukmejian
• 1980: Demolish pump house at 553 W Palm Drive; issued to George Deukmejian • 1980: Grading at 950 N Silent Ranch Drive, 553 W Palm Drive, contractor G. Bart Striker; issued to George Deukmejian
• 1999: New 4-car garage at 950 N Silent Ranch Drive, issued to Pam and Time Morales • 1999: Permit to demolish “old Girl Scout House, approx. 600 s.f.” at 935/950 N. Silent Ranch Drive; issued to Deukmejian Enterprises.

In addition to permits, observed alterations include the demolition of the original Rancho Los Alisos house, circa 1968-1974 and the construction of the crib dams and drainage channel on the property, which would not have received a building permit, for 1969-1970. Other alterations include the piercing of a section of stone-faced retaining wall along the lower road, north of the 950 Silent Ranch Drive house for an unpaved drainage channel for the crib dams.

NRHP/CRHR Statement of Significance
Criterion A/1: That are associated with events that have made a significant contribution to the broad patterns of our history.

The Rancho Los Alisos/Camp Aventura property has two phases: Rancho Los Alisos extending from 1907 through 1953 and Camp Aventura extending from 1953 through 1974. The Rancho Los Alisos phase is representative of the retirement years of wealthy lawyer, real estate investor and former judge Charles K. Silent. Silent’s property, though private, was opened as a public park for citizens of Glendora from 1907 to Silent’s death in 1918, then for years afterwards operated by the Silent Estate. Major components of this park and private property have been destroyed including most exotic plantings, the original orchards, and the original Greene & Greene designed house, however some key features of the landscaping remain including rock lined roads and paths, rock-lined water features, and a fish pool. The park likely made an impression on local Glendora visitors, however, the private home and garden does not appear to be host to a major historical event or influenced the growth of Glendora in any way.

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Camp Aventura was one of nearly 40 Girl Scouts of America organizations camps established in Southern California between 1930 and 1970. Only one remaining feature of the original camp, established in 1953 remains: a 3-stall restroom and washroom building. The other buildings were demolished by the Navy Seabees and George Deukmeijian between 1973 and 1974. As with Rancho Los Alisos, the camp may have made an impression on its occasional users, but did not particularly influence the growth of Glendora, or host any significant historical events.

Despite local popularity as a public park and later as a Girl Scout campground, no significant historical associations were found in the course of research. Due to a lack of identified significant associations with events important to history, the Rancho Los Alisos/Camp Aventura property does not appear eligible under NRHP/CRHR Criterion A/1.

Criterion B/2: That are associated with the lives of persons significant in our past.

Despite this association, Silent’s relationship with rancho Los Alisos/Camp Aventura is after the influential period of his life, after he had retired from his law practice and stopped working as Parks Commissioner. Rancho Los Alisos was not associated with the period of historical influence in Silent’s life; therefore, the Rancho Los Alisos/Camp Aventura property does not appear eligible under NRHP/CRHR Criterion B/2.

Criterion C/3: That embody the distinctive characteristics of a type, period, or method of construction, or that represent the work of a master, or that possess high artistic values, or that represent a significant and distinguishable entity whose components may lack individual distinction.

The Rancho Los Alisos property was initially built between 1907 and 1910, in a mixed Rustic style and Spanish Colonial Revival style romantically associated with old California ranchos. The grounds around the house were landscaped, and contained horticultural gardens, walks, retaining walls, stone benches, fountains, pools, fishstocked ponds, orchards and experimental orchards, during the time Charles Silent was alive. The original house was probably designed by master architects Greene & Greene, however this could not be determined as the house and all associated outbuildings were demolished in the late 1960s. The only remaining features of the original 1907-1910 property are the rock-lined landscaping features, including a pool, fountain, rock retaining walls, rock stairs and rock-lined paths throughout the property. These features have been allowed to deteriorate or were partially demolished as more modern portions of the property were added, such as the partial demolition of a rock retaining wall to allow a channel outlet for the West crib dam (1970) structure. These concrete and rock structures have also been damaged or altered by fires and flood and subsequent repairs. While interesting in construction, the majority of rock structures, original landscaping, and the original buildings on the property have been lost and the remaining structures lack the integrity to convey significance under this criteria. They cannot be positively identified as the work of a master, as the Greene & Greene house plans from 1907 do not include landscaping or structures aside from the main house. The structures have deteriorated and no longer possess high artistic value, and are not part of a district or entity whose components lack individual distinction.

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narrowed down to either Paul R. Hunter or Tryon & Foy, neither of which can be considered master architects. The building has no artistic value and while it was originally a component of a larger Girl Scout-related campground, it is the only remaining features and as such does not adequately convey this distinctive association. Therefore, the Rancho Los Alisos/Camp Aventura property does not appear eligible under NRHP/CRHR Criterion C/3.

Criterion D/4: That have yielded, or may be likely to yield, information important in prehistory or history.

The Rancho Los Alisos/Camp Aventura property is not likely to yield information important to understanding prehistory or history. Therefore, the Rancho Los Alisos/Camp Aventura property does not appear eligible under NRHP/CRHR Criterion D/4.

City of Glendora Historic Resource or Landmark Designation Criteria

1. The proposed preserved features exemplify or reflect special elements of historical, architectural, archaeological, cultural, or aesthetic heritage.

As stated above in Criteria A/1 and C/3, the remaining stone landscaping structures (1907-1910) and remaining restroom building (1955-1956) do not reflect special elements of historical, architectural, archaeological, cultural, or aesthetic heritage of Glendora. Therefore, the crib dams and channel are not eligible as a City of Glendora Historic Resource or Landmark under Criterion 1.

2. The proposed preserved features are identified with persons or events significant in local, state, or national history.

Archival research identified an association with influential lawyer, real estate developer and former judge Charles K. Silent, who is likely a significant person at the local and possibly state level. However, the Rancho Los Alisos property and Camp Aventura property do not retain an association with the influential period of Silent’s life, and are indicative only of his retirement and his posthumous estate transactions. No important person was identified in association with the Girl Scout camp. Therefore, Rancho Los Alisos/Camp Aventura are not eligible as a City of Glendora Historic Resource or Landmark under Criterion 2.

3. The proposed features embody distinctive characteristics of a style, type, period or method of construction or are valuable examples of the use of indigenous materials or craftsmanship.

Rancho Los Alisos/Camp Aventura no longer embody the characteristics of their original styles, periods, or methods of construction due to integrity issues and overall loss of the majority of concurrent features (i.e. Rancho Los Alisos has lost the original house, all associated outbuildings, and all original landscaping; Camp Aventura has lost the original 11 other campground buildings and major activity surfaces). Therefore, Rancho Los Alisos/Camp Aventura are not eligible as a City of Glendora Historic Resource or Landmark under Criterion 3.

4. The proposed preserved features are representative of the notable work of a builder, designer or architect.

Archival research failed to resolve whether the Rancho Los Alisos stone structures were designed by architects Greene & Greene as landscaping plans for the property have not been retained. Archival research also failed to identify if the Camp Aventura restroom is associated with architect Paul R. Hunter or Tryon & Foy, nor is the building definitively visibly the work of either architect. In both cases, the remaining Rancho Los Alisos/Camp Aventura structures and buildings are not representative of the notable work of a builder, designer, or architect. Therefore, Item #8. Page 905
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Rancho Los Alisos/Camp Aventura are not eligible as a City of Glendora Historic Resource or Landmark under Criterion 4.

Integrity Discussion
The Rancho Los Alisos/Camp Aventura buildings and structures retain only integrity of location, as they remain in their original locations. These features do not retain integrity of setting as the setting of both Rancho Los Alisos and Camp Aventura have been lost in subsequent fires, residential subdivision development, and flood control structure development. Enough of the Rancho Los Alisos or Camp Aventura settings have been altered, removed, or redeveloped such that integrity of setting is no longer intact. These features also do not retain integrity of design, materials or workmanship as all stone and concrete structures are in advanced states of decay, sometimes with the entire stone facing section missing. The Camp Aventura building has had several material portions removed so discerning original design intent, materials or workmanship was not possible. All features do not retain integrity of feeling as they do not convey the feeling of a mid-century Girl Scout camp with both accessible and remote camp sites nor convey the feeling of an early twentieth century several hundred-acre estate and intermittent park. Finally, no features retain integrity of association as all association with the Silent Estate and with the Los Angeles Girl Scout Council has been lost by the encroaching residential subdivision development.

5.2 USFS and LACFCD concrete crib dams and
channel structures
West crib dam (1970)
The West crib dam is a concrete crib check dam, built in 1970 located in the west-most canyon of the property, northwest of the 950 Silent Ranch Drive house (Figure 21). The dam was one of forty such concrete crib check dams constructed after a fire and flooding event in 1969. The dam is constructed of reinforced concrete beams laid in crib bays with no mortar and metal netting behind which rock and soil may accumulate in a debris cone while allowing water the pass through the dam. The dam portion is a squared U shape, extending 75 feet wide (11 visible crib widths) by 6 feet thick, and rises near 20 feet at its height and 15 feet in the middle. A concrete slurry mix called gunnite was applied to a central crib to form a spillway/pour-over location. The lower concrete sill below the dam rises roughly 2-3 feet above the ground surface. Between the dam and sill the hillside to the north and south are both covered with a gunnite, which was intended to prevent erosion of the hillside between the dam and sill, and erosion around the dam footings. One concrete beam on the upper right side of the dam bears the incised mark of “USFS 1970 W 12” and a metal plaque from the LACFCD. A pair of metal bars are attached to right side of the dam face, to act as ladder with the crib beams as rungs.

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Figure 21. West crib dam, with dam in background, concrete sill in foreground, looking northwest (IMG_1264) Center crib dam (1970)
The Center crib dam is a concrete crib check dam, built in 1970 located in the second-from-west canyon of the property, northeast of the 950 Silent Ranch Drive house (Figure 22). The dam was one of forty such concrete crib check dams constructed after a fire and flooding event in 1969. The dam is constructed of reinforced concrete beams laid in crib bays with no mortar and metal netting behind which rock and soil may accumulate in a debris cone while allowing water the pass through the dam. The dam portion is a squared U shape, extending 15 feet wide (4 visible crib widths) by 6 feet thick, and rises approximately 12 feet at its height and 8 feet in the middle. Gunnite was applied to the central crib from ground surface to top of dam to form a spillway. No lower sill was visible, through thick vegetation growth. The hillside to the east and west of the area below the dam are covered with a gunnite, rising from visible ground surface to a few feet above the lip of the dam. One concrete beam on the upper right side of the dam bears a metal plaque from the LACFCD. A pair of metal bars are attached to right side of the dam face, to act as ladder with the crib beams as rungs.

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Figure 22. Center crib dam, looking north (IMG_1332)
East crib dam and channel (1970)
The East crib dam is a concrete crib check dam, built in 1970 located in the east-most canyon of the property, northeast of the 950 Silent Ranch Drive house (Figure 23). The dam was one of forty such concrete crib check dams constructed after a fire and flooding event in 1969. The dam is constructed of reinforced concrete beams laid in crib bays with metal netting behind which rock and soil may accumulate in a debris cone while allowing water the pass through the dam. The dam portion is a squared U shape, extending approximately 85 feet wide (14 visible crib widths) by 6 feet thick, and rises approximately 24 feet at its height and 20 feet in the middle. Gunnite was applied to a central crib to form a spillway/pour-over location. The lower concrete sill below the dam rises roughly 3 feet above the channel surface. Between the dam and sill, as well as south of the sill, the hillside to the east and west are both covered with gunnite to stabilize the hillside. On the west hillside gunnite slurry wall, however an oak tree is actively growing out a large crack and concavity in the slurry wall, showing a wall thickness of roughly 2 inches. One concrete beam on the upper right side of the dam bears the incised mark of “USFS 1970 E 4” and a metal plaque from the LACFCD. A pair of metal bars are attached to right side of the dam face, to act as ladder with the crib beams as rungs.

South of the crib dam, a gunnite-lined channel meanders south towards a culvert along Palm Drive. The channel width varies along the length with a shallow smooth-bottomed basin shape approximately 30 feet wide immediately below the dam. 200 feet south of the dam, the channel is a steep V-shape, 16 feet wide and 5 feet deep. 550 feet south of the dam, the channel is a steep V-shape, 10 feet wide and 5 feet deep (Figure 24). 900 feet south of the dam, a dirt road crosses the channel and the channel walls slope to accommodate the road; here the channel is 0 feet deep and 12 feet wide. At the culvert along Palm Drive, the channel is 8 feet wide and 6 feet deep.

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Figure 23. East crib dam, looking north (IMG_1320)
Figure 24. Concrete lined channel, 550 feet south of dam, looking north (IMG_4019) Item #8. Page 909
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Identified Alterations
No permits were available from the Los Angeles County Department of Public Works for the concrete crib dams or channel. No observed alterations were noted in the course of survey. The crib dams are in fair condition, but heavily overgrown by vegetation and the debris cone behind each dam has completely filled and level to the top of each dam.

NRHP/CRHR Statement of Significance
Criterion A/1: That are associated with events that have made a significant contribution to the broad patterns of our history.

Fire and flood/mudslide patterns were typical to this area and most down-stream communities south the canyon outlets of San Gabriel Mountains. The crib dams were constructed as part of a larger joint USFS and LACFCD infrastructure program which created the larger Hook Canyon debris dam and channel, as well as 40 other concrete crib dams. As such, the dams on the proposed project APE do not distinguish themselves as particularly important structures that made a significant contribution to the broad patterns of local Glendora history. Therefore, the three crib dams and channel do not appear eligible under NRHP/CRHR Criterion A/1.

Criterion B/2: That are associated with the lives of persons significant in our past.

Archival research failed to identify any associations with significant persons. Due to a lack of identified significant associations with important persons in history, the USFS/LACFCD crib dams do not appear eligible under NRHP/CRHR Criterion B/2.

The three dams and channel were constructed in 1970 as a joint project between USFS, LACFCD, with financial aid from the Army Corps of Engineers and the City of Glendora. They are typically constructed of concrete beams arranged in cribs and built to various heights. Crib dams were not a new, novel, or improved engineering method for dealing with debris floods. The technique of using crib dams to control land erosion and heavy sediment flow originated in Europe and was used in the San Gabriel Mountains by the USFS as early as 1915. Because the dams are meant to slowly backfill, the multiple historical flood events in Los Angeles (1916, 1938) eventually covered and made obsolete earlier crib dams. Multiple crib dam building periods were identified by the USFS as important projects: a concrete arch check dam in Arroyo Seco Canyon (1942); the Coon Canyon Stabilization Project (1950); and the Los Angeles River Watershed Project (1954-1974), however this last did not provide crib dams in Glendora.

The three crib dams in the study area are typical in their construction and offer no insight into engineering techniques or identified major projects. Archival research did not indicate an association between the dams and channel and a master engineer. The dams are of utilitarian construction and do not possess artistic value. While Item #8. Page 910
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the dams and channel are part of an entity of dams built after the 1969 mudslides and flood, they are neither significant or distinguishable from earlier period crib dams constructed for similar regions throughout the San Gabriel National Forest. Therefore, the crib dams and channel not appear eligible under NRHP/CRHR Criterion C/3.

Criterion D/4: That have yielded, or may be likely to yield, information important in prehistory or history.

The crib dams and channel are not likely to yield information important to understanding prehistory or history.

Therefore, the crib dams and channel donot appear eligible under NRHP/CRHR Criterion D/4.

City of Glendora Historic Resource or Landmark Designation Criteria

1. The proposed preserved features exemplify or reflect special elements of historical, architectural, archaeological, cultural, or aesthetic heritage.

The three crib dams and the channel are utilitarian in construction and constructed by the USFS and LACFCD in 1970, in response to a flood and mudslide event in 1969. However, in the larger Glendora-area history this flood and mudslide event was one of many in Glendora’s history, and resulted in the construction of 40 similar structures.

These structures neither exemplify nor reflect special elements of historical, architectural, archaeological, cultural, or aesthetic heritage of Glendora. Therefore, the crib dams and channel are not eligible as a City of Glendora Historic Resource or Landmark under Criterion 1.

2. The proposed preserved features are identified with persons or events significant in local, state, or national history.

Archival research failed to identify any associations with significant persons at the local, state, or national level.

Therefore, the crib dams and channel are not eligible as a City of Glendora Historic Resource or Landmark under Criterion 2.

3. The proposed features embody distinctive characteristics of a style, type, period or method of construction or are valuable examples of the use of indigenous materials or craftsmanship.

The three crib dams are 1970s-era concrete crib dams, and typical of the method of construction of crib dams by USFS. They are utilitarian in construction and do not embody a particular style, type, or period. Therefore, the crib dams and channel are not eligible as a City of Glendora Historic Resource or Landmark under Criterion 3.

4. The proposed preserved features are representative of the notable work of a builder, designer or architect.

Archival research failed to identify any associations with a specific architect, designer, or engineer. Therefore, the crib dams and channel are not eligible as a City of Glendora Historic Resource or Landmark under Criterion 4.

Integrity Discussion
All three dams and the channel maintain integrity of location and setting as neither have changed since their construction in 1970. The dams have infilled, however there appear to be no notable alterations, repairs, demolitions, or additions, and therefore the three dams and channel maintain integrity of design, materials and workmanship. The dams and channel still evoke the feeling of utilitarian flood control structures and therefore Item #8. Page 911
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retain integrity of feeling. Though the dams retain signage by USFS and LACFCD, they appear to not be actively maintained and do not retain integrity of association.

5.3 MWD Upper Feeder Pipeline segment (Monrovia
No. 1) and Above-ground Structures
The Monrovia No. 1 tunnel and hatch structure are components of a larger water conveyance system called the Upper Feeder pipeline, completed in 1939, owned and operated by the Metropolitan Water District of Southern California (MWD), and operating today as an active utility. The Upper Feeder was designed and constructed concurrently with the Colorado River Aqueduct as part of the distribution system, which furnished water to participating cities for distribution b local municipal water departments.

MWD Upper Feeder Pipeline segment: Monrovia No. 1 tunnel (1937) The MWD Upper Feeder Pipeline segment: Monrovia No. 1 tunnel is a subterranean structure that transects the proposed project APE from a point due east of the 950 Silent Ranch Drive main house building to a point northeast of the 950 Silent Ranch Drive main house building, in the eastern section of the proposed project APE. No portion of the Monrovia No. 1 tunnel was accessible for survey, due to it being underground. Historical MWD source document that entirety of the 41.6 miles from Lake Matthews to the east portal of Monrovia No. 1 tunnel was constructed of welded steel and precast concrete pipe. The Monrovia No. 1 tunnel extended 7,868 feet from portal to portal, and was a concrete lined pressure tunnel in rock substrate, and was 10 feet in diameter, with light supper of steel ribs and timber lagging occasionally placed as-needed (Weymouth 1939: 266-269).

Concrete access point hatch 2256-93 (no date)
The concrete access hatch structure and above ground structure is part of the MWD Upper Feeder Pipeline located northeast of the 950 Silent Ranch Drive main house building, at the outlet of a wide gully. The hatch structure consists of a 6-foot diameter, circular concrete access point that rises 1-2 feet above the ground surface, with a rectangular asbestos lid with a crosshatch pattern (Figure 25). Date of construction for the hatch is unknown. The original subsurface section of the MWD Upper Feeder was constructed between 1936 and 1939; however, the asbestos lid does not appear to be of 1930s construction. The hatch structure is labeled with stenciled paint on the top and side with “2256-93.”
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Figure 25. MWD hatch, looking northwest (IMG_1339)
Identified Alterations
No permits were available from the Metropolitan Water District of the City of Glendora for the infrastructure related to the Upper Feeder. No observed alterations were noted in the course of survey.

NRHP/CRHR Statement of Significance
Criterion A/1: That are associated with events that have made a significant contribution to the broad patterns of our history.

The section of Upper Feeder pipeline within the study area is subterranean Monrovia No. 1 tunnel with only one visible, above-ground structure: the concrete access hatch. Monrovia No. 1 tunnel is an underground pipeline and critical segment of the MWD Upper Feeder pipeline, the first multi-city municipal water distribution system of its kind in the region. The entire Upper Feeder pipeline system was designed in 1931, contract for the Monrovia No. 1 tunnel was awarded to West Construction Company in 1934, the right-of-way easement was acquired in 1935 through the Silent Ranch Estate, and the Monrovia No. 1 tunnel was completed in 1937. Water first flowed through the distribution system in 1941. No date of construction could be ascertained for this hatch; however, it is assumed that the construction date is concurrent with the Monrovia No. 1 tunnel: 1937. Both Monrovia No.1 tunnel and the access hatch are components of the larger Upper Feeder pipeline and distribution system for the Colorado River Aqueduct. The entire distribution the Upper Feeder pipeline belongs to extends 150-miles and serves participating cities in the greater metropolitan Los Angeles area, the Inland Empire, San Diego County, and other Southern California areas. The Upper Feeder pipeline is the first segment of the distribution system for the MWD Colorado River Aqueduct, extending 60 miles from the Colorado River Aqueduct’s western terminus at Lake Matthews to the San Rafael tunnel between Pasadena and Glendale. The construction of the distribution system and Upper Feeder pipeline made a significant contribution to the board pattern of history as part of the transportation and distribution Item #8. Page 913
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of Colorado River water, an enabling force for the intensive economic and residential development of Southern California.

The MWD Upper Feeder was instrumental to the transportation and distribution of Colorado River water to participating cities in Southern California. After Colorado River traversed the Mojave Desert from Nevada to Riverside in the Colorado River Aqueduct, the Upper Feeder pipeline was the practical means by which the participating cities accessed Colorado River water. The need for Colorado River water was dire in the 1920s, and the 2,200 square miles of coastal plain surrounding the City of Los Angeles was ripe for residential, commercial, industrial, and agricultural development. However, prior to receiving Colorado River water, municipalities in the arid region relied on outdated and overtaxed irrigation systems, artesian wells and groundwater, or private water companies to furnish water, or face annexation by City of Los Angeles in order to access the Los Angeles Department of Water and Power’s Owens River water sources. Most smaller municipalities in the region simply lacked the resources to import water like Los Angeles on their own. After the Colorado River Compact enabled Arizona, California Colorado, Nevada, New Mexico, Utah and Wyoming to divert portions of Colorado River water in 1923, the Metropolitan Water District of Southern California (MWD) was established in 1928, as a result of the Metropolitan Water Act. The Metropolitan Water Act outlined how to the Colorado River Aqueduct and distribution system would be located and constructed. Construction of both distribution system and Colorado River Aqueduct began in 1931. 150 miles of distribution system were completed in 1939 and 242 miles of Colorado River Aqueduct were completed in 1941.

The Upper Feeder was a segment of the distribution system of the MWD Colorado River Aqueduct, and the means by which the participating cities in the greater metropolitan Los Angeles area, the Inland Empire, San Diego County, and other Southern California areas got access to Colorado River water after the completion of the Hoover Dam.

The MWD Upper Feeder pipeline, as well as the rest of the distribution system and Colorado River Aqueduct, were major construction programs affording thousands of jobs to Californians during the Great Depression. After both projects were completed, the increased water supply and made it possible for Southern California to enjoy widespread economic development and to be settled so densely.

For linear, water conveyanceresources to be found eligible under Criterion A/1, it must be a key piece of the overall system. In this case, the Monrovia No. 1 tunnel is a key portion of the Upper Feeder pipeline, facilitating its portage from the south side of the San Gabriel foothills, to the San Gabriel River canyon. Further, the Monrovia No. 1 tunnel and hatch maintain their original alignment and location, which is critical to understanding their importance and significance as a historically significant piece of water infrastructure. The Monrovia No. 1 tunnel and hatch also maintain its subterranean setting, situated in the original undeveloped suburban foothill area of Glendora. Finally the Monrovia No. 1 tunnel and hatch continue to function as a water conveyance system operated by Metropolitan Water District of Southern California (MWD). While setting is less important for an underground feature, maintaining the original alignment, association with MWD, and its continued use as a water conveyance structure are important are the character-defining features of the Monrovia No. 1 tunnel and hatch As such, the Monrovia No. 1 tunnel segment transecting the proposed project APE and the above-ground access hatch, are recommended eligible for NRHP/CRHR Criterion A/1, as a component of the larger MWD Upper Feeder pipeline for the period 1931-1941, for transportation and distribution of Colorado River water to participating municipalities in Southern California, which was an enabling force for the intensive economic and residential development of Southern California.

Criterion B/2: That are associated with the lives of persons significant in our past.

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Archival research failed to identify any associations with specific significant persons. Due to a lack of identified significant associations with important persons in history, the MWD Upper Feeder and all associated components do not appear eligible under NRHP/CRHR Criterion B/2.

The entire Upper Feeder pipeline system was designed in 1931, contract for the Monrovia No. 1 tunnel was awarded to West Construction Company in 1934, the right-of-way easement was acquired in 1935 through the Silent Ranch Estate, and the Monrovia No. 1 tunnel was completed in 1937. Water first flowed through the distribution system in 1941. No date of construction could be ascertained for this hatch; however, it is assumed that the construction date is concurrent with the Monrovia No. 1 tunnel: 1937. The MWD Upper Feeder pipeline was designed by Metropolitan Water District engineer R.B. Diemer and multiple contractors were used to complete the above and below ground sections. Monrovia No. 1 tunnel was completed by contractor West Construction Company, and the majority of other concrete pipe sections completed by contractor J.F. Shea Company Inc. Like the Colorado River Aqueduct the scale and importance of the distribution system, which totaled over 150 miles and served dozens of cities across Southern California. The Upper Feeder segment between Lake Matthews and Morris Reservoir is 30+ miles long and passes through the proposed project APE in a series of subterranean tunnels. No portion of the tunnels are visible as above ground features except for a single concrete hatch. As such, this report cannot offer comment on the type or method of construction. Adequate records of the construction of the section through the proposed project APE are well recorded; however, construction techniques could not be confirmed as the line itself was not visible during the field visit.

Concrete pipelines and tunnel construction are ubiquitous water infrastructure components and the Monrovia No. 1 tunnel and MWD Upper Feeder pipeline as a whole do not distinguish themselves other than by its size. The Upper Feeder pipeline as a whole is associated with MWD engineer R.B. Diemer, who despite his later role as chief engineer of MWD for nine years, does not rise to the level of master engineer. The Monrovia No. 1 tunnel is utilitarian infrastructure and does not possess high artistic value. Finally, the Monrovia No. 1 tunnel and the concrete hatch are components of a significant and distinguishable work of twentieth century water engineering and a major infrastructure development project, however they are subsurface components and not visible. Therefore, they are not representative of the pipeline as a whole. Therefore, the MWD Upper Feeder subsurface tunnel segment and associated infrastructure, including the hatch, do not appear eligible under NRHP/CRHR Criterion C/3.

Criterion D/4: That have yielded, or may be likely to yield, information important in prehistory or history.

The Upper Feeder pipeline is not likely to yield information important to understanding prehistory or history.

Therefore, Upper Feeder pipeline does not appear eligible under NRHP/CRHR Criterion D/4.

City of Glendora Historic Resource or Landmark Designation Criteria

1. The proposed preserved features exemplify or reflect special elements of historical, architectural, archaeological, cultural, or aesthetic heritage.

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The Monrovia No. 1 tunnel and hatch, which traverse the proposed project APE, exemplifies special elements of City of Glendora’s history. The addition of this water to the city existing water system allowed for the continuation of and assurance of water for irrigated crops in Glendora, allowing the Glendora citrus industry to persist until the mid-1960s, when residential and economic development pressure overrode the citrus industry’s land requirements.

Therefore, the Monrovia No. 1 tunnel and hatch are recommended eligible as a City of Glendora Historic Resource or Landmark under Criterion 1.

2. The proposed preserved features are identified with persons or events significant in local, state, or national history.

Archival research failed to identify any associations with significant persons at the local, state, or national level.

Therefore, the Monrovia No. 1 tunnel and hatch are not eligible as a City of Glendora Historic Resource or Landmark under Criterion 2.

3. The proposed features embody distinctive characteristics of a style, type, period or method of construction or are valuable examples of the use of indigenous materials or craftsmanship.

The Monrovia No. 1 tunnel and hatch are not particularly outstanding or innovative examples of 1930s-era monumental-scale water infrastructure. All components of the Upper Feeder tunnel in the APE are underground and Dudek was not able to verify the condition, construction, or alterations to the pipeline. Therefore, the Monrovia No. 1 tunnel and hatch are not eligible as a City of Glendora Historic Resource or Landmark under Criterion 3.

4. The proposed preserved features are representative of the notable work of a builder, designer or architect.

Therefore, the Monrovia No. 1 tunnel and hatch are not eligible as a City of Glendora Historic Resource or Landmark under Criterion 4.

Integrity Discussion
Integrity is the ability of a property to convey its significance. Under NRHP Criterion A and CRHR Criterion 1, a significant water conveyance resource must retain the following physical attributes as they relate to the integrity of location, setting, and association:
• Location: original alignment
• Setting: remains subterranean
• Association: continues to function as a water conveyance system Dudek recommends that the pipeline retains integrity of location as it maintains its original 1930s alignment, as confirmed through map research. The Monrovia No. 1 tunnel segment also retains integrity of its setting, as the pipe is still under the ground surface. Because the pipeline is a subterranean feature, integrity of the aboveground setting is not necessary for the pipeline to convey its significance. The pipeline retains integrity of association with the MWD as the pipeline retains its original ownership and function. Integrity of design, materials, workmanship and feeling are not required for a water conveyance resource to convey its significance under Criterion A/1.

Therefore Monrovia No. 1 tunnel and hatch retain the requisite aspects of integrity to convey their significance under Criterion A/1.

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5.4 Summary of Evaluation Findings
Within the APE, one resource is recommended eligible for the NRHP, CRHR and City of Glendora Historic Resource of Landmark designation: the Monrovia No. 1 tunnel and hatch. The Monrovia No. 1 tunnel and hatch are recommended eligible under Criterion A/1/1 as a component of the MWD Upper Feeder pipeline, for the period 1931-1941 for representing a critical component of a larger water infrastructure, the MWD Upper Feeder pipeline.

The MWD Upper Feeder pipeline was instrumental to addressing the water needs of the greater metropolitan area of Los Angeles, and was an enabling force for the intensive economic and residential development of Southern California. The Monrovia No. 1 tunnel and hatch was evaluated in accordance with Section 15064.5(a) (2)‐(3) of the CEQA Guidelines using the criteria outlined in Section 5024.1 of the California Resources Code, and it appears to be a historical resource for the purposes of CEQA and a historical property for the purposes of Section 106 of the NHPA (36 CFR Part 800). Dudek recommends this resource be assigned a California Historical Resource Status Code of 3D (appears eligible for NR as a contributor to a NR eligible district through survey evaluation).

The remaining resources located at 950 North Silent Ranch Drive (APN: 8684-045-004): the Rancho Los Alisos Structures, Camp Aventura building, and joint Forest Service and County Flood Control District dams and channel do not appear not eligible for the NRHP, CRHR, or as a City of Glendora historic resource or landmark due to a lack of significant historical associations and architectural merit. Therefore, the property is not considered an historical resource for the purposes of CEQA or an historic property for the purposes of Section 106 of the NHPA. No management recommendations are required for cultural resources. These resources have been assigned a California Historical Resource Status Code of 6Z (found ineligible for the NRHP, CRHR, or local designation through survey evaluation).

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6 Findings and Conclusions

6.1 Summary of Findings
One resource within the proposed project APE was recommended eligible for the NRHP, CRHR, and City of Glendora Historic Resource or Landmark Designation and are considered an historic property under Section 106 of the NHPA and an historical resource under CEQA: the Monrovia No. 1 tunnel and hatch. Dudek recommends the Monrovia No. 1 tunnel and hatch are eligible under Criterion A/1/1 for the period 1931-1941 for representing a critical component of a larger water infrastructure, the MWD Upper Feeder pipeline. The MWD Upper Feeder pipeline was instrumental to addressing the water needs of the greater metropolitan area of Los Angeles, and was an enabling force for the intensive economic and residential development of Southern California.

6.2 Consideration of Adverse Effects to Historic Properties Under Section 106 of the NHPA, an adverse effect is found when an undertaking may alter, directly or indirectly, any of the characteristics of a historic property that qualify the property for inclusion in the NRHP in a manner that would diminish the integrity of the property's location, design, setting, materials, workmanship, feeling, or association. Consideration shall be given to all qualifying characteristics of a historic property, including those that may have been identified subsequent to the original evaluation of the property's eligibility for the NRHP.

Adverse effects may include reasonably foreseeable effects caused by the undertaking that may occur later in time, be farther removed in distance or be cumulative (36 CFR Part 800.5(1)).

In July 2019, Metropolitan Water District of Southern California (MWD) sent Giron Engineers, Inc. a letter commenting on plans submitted for the proposed project and requiring the project proponents to: make accommodations for MWD vehicles and build an MWD-accessible right-of-way in the proposed project APE; provide protections such as bollards or gates for above ground MWD structures such as manholes or hatches; provide MWD with detailed plans for any protection provisions built for MWD resources as a result of the project; provide plans for landscaping or other improvements within the MWD proposed right-of-way; provide details of any non-potable utilities for MWD review; and to include provisions for loads imposed on the pipeline. The letter further cautions that any facility constructed within the MWD easement is subject to the paramount right of MWD to use the easement for the purpose it was required. MWD reserved the right to remove facilities from the easement and to block access to their right-of-way at any time (MWD 2019). This letter provides for the protection of the structure of the Monrovia No. 1 tunnel segment of the MWD Upper Feeder pipeline which transects the proposed project APE. If the recommendations and requirements of MWD are followed as part of the proposed project, Dudek does not anticipate any potential effect on the Monrovia No. 1 tunnel segment of the MWD Upper Feeder pipeline. This letter has been included in Appendix D.

As stated above the Monrovia No. 1 tunnel and hatch appears eligible for listing in the NRHP Criterion A and CRHR Criterion 1. The character-defining features associated with the Monrovia No. 1 tunnel and hatch are its location, original alignment, association with MWD, and continued function as a water conveyance system. The proposed project would develop a residential subdivision, and construction includes grading, fill deposits, utilities trenching, road construction, driveway construction, and construction of residential buildings over the MWD pipeline easement. Given the above summarized steps Giron Environmental, Inc. and MWD will take to protect the MWD Upper Feeder pipeline in the proposed project APE, no intrusion, modification, or destruction or any aspect of this water system are proposed or Item #8. Page 918
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expected as part of this project. The historic property will still be able to convey is significance following proposed project implementation. As a result the recommended finding is No Adverse Effect to the Monrovia No. 1 tunnel and hatch.

For a detailed assessment of potential adverse effects please refer to Table 4.

Table 4. Application of Criteria of Adverse Effects for the Monrovia No. 1 tunnel and hatch within the Proposed Project APE
Examples of adverse effects on historic properties include, but are not limited to:

Assessment of potential adverse effects
(i) Physical destruction of or damage to all or part
of the property;
Proposed construction will not result in the physical destruction of or damage to all or part of the Monrovia No. 1 tunnel and hatch.

As the MWD Upper Feeder pipeline is a public utility and still owned and operated by MWD, protection measures for the pipeline are being undertaken by MWD and the project proponent as part of the project.

MWD has recommended that above-ground features be avoided and protected from vehicle damage by bollards and gates. Additionally MWD requires that when ground cover over the pipeline is between 3 and 4 feet of cover, that equipment must be restricted so the load on the pipe meets AASHTO H-20 loading requirements.
(ii) Alteration of a property, including restoration, rehabilitation, repair, maintenance, stabilization, hazardous material remediation, and provision of handicapped access, that is not consistent with the Secretary's Standards for the Treatment of Historic Properties (36 CFR part 68) and applicable guidelines;
Proposed construction will not result in the alteration of the Monrovia No. 1 tunnel and hatch inconsistent with the Secretary's Standards for the Treatment of Historic Properties (36 CFR part 68) and applicable guidelines
(iii) Removal of the property from its historic
location;
Proposed construction will not result in the removal of the Monrovia No. 1 tunnel and hatch from their historic location.
(iv) Change of the character of the property's use or of physical features within the property's setting that contribute to its historic significance;
The proposed project will change the setting of the Monrovia No. 1 tunnel and hatch; however, as discussed above in Section 5.3 Integrity, because the pipeline is a subterranean feature, integrity of the aboveground setting is not necessary for the pipeline to convey its significance.
(v) Introduction of visual, atmospheric or audible
elements that diminish the integrity of the property's significant historic features;
The proposed project will introduce visual elements: 12 single-family residential properties to the southern section of the Monrovia No. 1 tunnel and the area surrounding the access hatch. However, as discussed above in Section 5.3 Integrity, because the pipeline is a subterranean feature, integrity of the aboveground setting is not necessary for the pipeline to convey its significance. Therefore, the proposed project will not diminish the integrity of the property's significant historic features.
(vi) Neglect of a property which causes its deterioration, except where such neglect and deterioration are recognized qualities of a property of religious and cultural significance to an Indian tribe or Native Hawaiian organization; and
Proposed construction will not result in the neglect or deterioration of the Monrovia No. 1 tunnel and hatch.

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6.3 Management Recommendations
All work for this inventory and evaluation report has been conducted as required under the Section 106 regulations (36 CFR Part 800 et seq.) and in accordance with Section 15064.5(a) (2)‐(3) of the CEQA Guidelines using the criteria outlined in Section 5024.1 of the California Resources Code. The overall finding for this study is that no historic properties listed in, or eligible for inclusion in the NRHP, CRHR, or local Glendora Historic Resource or Landmark list will be impacted by the proposed project.

Assessment of potential adverse effects
Transfer, lease, or sale of property out of Federal ownership or control without adequate and legally enforceable restrictions or conditions to ensure long‐term preservation of the property's historic significance.

Proposed construction will not result in the transfer, lease, or sale of the Monrovia No. 1 tunnel and hatch out of Metropolitan Water District of Southern California ownership or control.

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7 Bibliography
Argus (Covina Argus). 1910. “Above the Haze-Clouds on Sun-Flooded Los Alisos.” Newspapers.com: Covina Argus (Covina, California). May 28, 1910, pg. 2.

Argus. 1921. “The Silent Homestead.” Newspapers.com: Covina Argus. July 15, 1921, pg. 8.

Argus. 1935. “Citrus Area Confers with Metropolitan.” Newspapers.com: Covina Argus. July 26, 1935, pg. 1.

Bean, L.J., and C.R. Smith. 1978. Gabrielino. In California, edited by Robert F. Heizer, pp. 538-549. Handbook of North American Indians, Vol. 8, William C. Sturtevant, general editor, Smithsonian Institution, Washington, D.C.

California Geological Survey. 2002. California Geomorphic Provinces: Note 36. 4 pp.

City of Glendora. 1999. Historic Preservation Element of the City of Glendora General Plan. Glendora California:

City of Glendora. Prepared June 14, 1999. Accessed July 31, 2019. http://www.cityofglendora.org/home/showdocument?id=24496 Cleland, R.G. 1941. The Cattle on a Thousand Hills: Southern California, 1850-80, sixth printing, 2005. The Huntington Library, San Marino, California.

Creason, Glen. 2015. “CityDig: This 1938 Map Details Every Dramatic Stretch of the 242-Mile-Long Colorado River Aqueduct.” Los Angeles Magazine. Published February 11, 2015, accessed August 8, 2019. https://www.lamag.com/citythinkblog/citydig-1938-map-details-every-dramatic-stretch-242-mile-longcolorado-river-aqueduct/ Desert Sun. 1938. “Construction of Colorado River Aqueduct Nears Completion.” California Digital Newspaper Collection: Desert Sun Volume XI, No 51, July 22, 1938.

Dibblee, T.W. and Ehrenspeck, H.E. 1998, Geologic map of the Mt. Wilson and Azusa quadrangles, Los Angeles County, California: Dibblee Geological Foundation, Dibblee Foundation Map DF-67, scale 1:24,000.

Dibblee, T.W. and J.A. Minch, 2002. Geologic map of the Glendora quadrangle, Los Angeles County, California:

Dibblee Geological Foundation, Dibblee Foundation Map DF-89, scale 1:24,000.

Erlandson, J.M. 1991. “Early Maritime Adaptations on the Northern Channel Islands.” In Hunter-Gatherers of Early Holocene Coastal California, edited by Jon M. Erlandson and Roger H. Colten, 101–112. Perspectives in California Archaeology, Vol. 1. Institute of Archaeology, University of California, Los Angeles.

Glendora Strikers. 1946. Pamphlet. “Conscientious Objectors Go On Strike.” Accessed August 15, 2019. http://civilianpublicservice.org/sites/default/files/sites/civilianpublicservice.org/files/documents/glendo ra-strikers.pdf
Greene & Greene, Architects. 1908. “Ranch houses for Judge Chas. Silent at Glendora, Cal.” 14 drawings various media 88.7 x 90.9 cm. (35 x 35 7/8 in.) or smaller. Greene & Greene Architectural Records & Paper Collections, Avery Architectural & Fine Arts Library. Accessed August 15, 2019. http://www.columbia.edu/cu/lweb/eresources/archives/avery/greene/html/subs/NYDA89-F763.html Item #8. Page 922
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Hager, William H. 2015. Hydraulicians in the USA 1800-2000: A biographical dictionary of leaders in hydraulic engineering and fluid mechanics. London: CRC Press. Accessed August 19, 2019. https://books.google.com/books?id=EAVCCwAAQBAJ&pg=PA1969&lpg=PA1969&dq=R.B.+Diemer+engi neer&source=bl&ots=HMpd2IyYxD&sig=ACfU3U11zHLrOcvKwe37Bw3erwoOULRc2w&hl=en&sa=X&ved= 2ahUKEwjDrL7F1I_kAhVjhq0KHXuxBXQQ6AEwEHoECAgQAQ#v=onepage&q=R.B.%20Diemer%20enginee r&f=false
Hinds, Julian. 1935. Letter to Honorable Board of Directors of the Metropolitan Water District of Southern California. RE: “Upper Feeder Line Right of Way and Waiver – Silent Estate.” December 6, 1935.

Accessed August 8, 2019. http://mwdh2o.com/WhoWeAre/Board/BoardMeeting/Board%20Archives/1935/12-Dec/Letter/064739488.pdf#search=silent%20ranch Jefferson, G.T. 1991. A Catalog of Late Quaternary Vertebrates from California. Natural History Museum of Los Angeles County, Technical Reports 7:1-174. Unpublished revision: 18 May 2012.

King, C.D. 1990. Evolution of Chumash Society: A Comparative Study of Artifacts Used in Social System Maintenance in the Santa Barbara Channel Region Before A.D. 1804. Revised Ph.D. dissertation with a new preface and updated bibliography. In The Evolution of North American Indians, edited by David Hurst Thomas. Garland Publishing, New York.

Kroeber, A.J. 1925. Handbook of the Indians of California. Bulletin 78, Bureau of American Ethnology, Smithsonian Institution. Government Printing Office, Washington, D.C. Reprinted 1976 by Dover Publications, Inc., New York.

Landers, J.D. 2001. Images of America: Glendora. Arcadia Publishing, Charleston, South Carolina.

LAT (Los Angeles Times). 1907a. “Large Tract Purchased: Judge Silent of Glendora Buys Land near Foothill Town.” Newspapers.com: The Los Angeles Times. May 19, 1907, pg. 72.

LAT. 1907b. “Lofty Bridge for Highway: Novelty Urged in Route of Foothill Boulevard.” Newspapers.com: The Los Angeles Times. December 19, 1907, pg. 23.

LAT. 1918. “Charles Silent Taken By Death.” Newspapers.com: The Los Angeles Times. December 15, 1918, pg. 9.

LAT. 1927. “Crop Worth King’s Ransom: Citrus Grown in Upper San Gabriel Valley Returns $7,000.” Los Angeles Times (1923-Current File): December 27, 1927. ProQuest Historical Newspapers: Los Angeles Times (1881-1990). Pg. 7.

LAT. 1934. “Great Aqueduct Moves Forward at Brisk Pace.” Newspapers.com: The Los Angeles Times. August 19, 1934, pg. 16.

LAT. 1936. “Giant Pipe Being Placed for Aqueduct Project.” Newspapers.com: The Los Angeles Times. March 26, 1936, pg. 28.

LAT. 1941. “Conscientious Objectors Arrive for Duty at West’s First Camp.” Newspapers.com: The Los Angeles Times. June 3, 1941, pg. 10.

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LAT. 1953. “Experts OK Girl Scout Camp Site.” Newspapers.com: The Los Angeles Times. July 24, 1953, pg. 51.

LAT. 1956. “Girls’ Camps Nestle Among Rare Flora on Ranch Made Into Garden.” Newspapers.com: The Los Angeles Times. September 2, 1956, pg. 107.

LAT. 1958. “Fashions to Aid Girl Scout Camp.” Newspapers.com: The Los Angeles Times. August 15, 1958, pg. 31.

LAT. 1959. “Girl Scouts Complete Payments on Camp.” Newspapers.com: The Los Angeles Times. February 12, 1959, pg. 56.

LAT. 1968. “Water Project: Tunneling Ends as Miners Hit Daylight.” Newspapers.com: The Los Angeles Times.

December 1, 1968, pg. 322.

LAT. 1969a. “Foothills Might Have Been Spared the Flood.” Newspapers.com: The Los Angeles Times. April 6, 1969, pg. 198.

LAT. 1969b. “Debris Control Dam to Be Built.” Newspapers.com: The Los Angeles Times. May 11, 1969, pg. 153.

LAT. 1969c. “Watershed Flood Work Will Be Undertaken.” Newspapers.com: The Los Angeles Times. October 30, 1969, pg. 136.

LAT. 1970. “Crib Dams.” Newspapers.com: The Los Angeles Times. July 19, 1970, pg. 230.

LAT. 1984a. Advertisement. “Silent Ranch Estates.” Newspapers.com: The Los Angeles Times. March 31, 1984, pg. 293.

LAT. 1984b. “San Gabriel Valley Digest Glendora.” Newspapers.com: The Los Angeles Times. May 10, 1984, pg. 308 LAT. 1985. Advertisement. “At Home.” Newspapers.com: The Los Angeles Times. June 1, 1985, pg. 25.

Lauten, John H. 1970. Letter to Board of Directors of the Metropolitan Water District of Southern California. RE:
“MWD v. Grizzle, Parcel 20 (Right of Way Parcel; 1604-6-9.” May 11, 1970. Accessed August 8, 2019. http://mwdh2o.com/WhoWeAre/Board/Board-Meeting/Board%20Archives/1970/05- May/Letter/064685600.pdf#search=%22glendora%20tunnel%22%201970 Leagle. 2019. “41 T.C.M. 738 (1981). T.C. Memo. 1981-24. George Deukmejian and Jean Deukmejian v.

Commissioner. United States Tax Court. Filed January 26, 1981. Accessed August 8, 2019. https://www.leagle.com/decision/198177941gdtcm7381594
McLeod, S.A. 2018. Vertebrate Paleontology Records Check for Paleontological Resources for the Proposed Glendora Hillside Subdivision Project, Dudek Project # 8375, in the City of Glendora, Los Angeles County, Project Area. Unpublished Records Search Results Letter from the Natural History Museum of Los Angeles County, Los Angeles, California.

Moratto, M.J. 1984. California Archaeology. Academic Press, New York.

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Morton, D.M., and F.K. Miller. 2006. Geologic Map of the San Bernardino and Santa Ana 30-minute x 60-minute quadrangles, California, Geology and Description of Map Units, Version 1.0: U.S. Geological Survey, OpenFile Report OF-2006-1217. 194 pp.

MWD. (Metropolitan Water District of Southern California). 2019. Letter to Amy Bledsoe, Giron Engineers, Inc. RE:
“Tentative tract Map No. 72413 – Revised Plans.”
NETR (Nationwide Environmental Title Research LLC). 2019a. Historic Aerial Photographs of Glendora area, dating from 1953, 1964, 1965, 1972, 1977, 1978, 1980, 1994, 2002, 2003, 2004, 2005, 2009, 2012, and 2014. Accessed August 6, 2019. https://www.historicaerials.com/viewer.

NETR. 2019b. Historic Topographical Maps of Glendora area, dating from 1897, 1898, 1902, 1904, 1908, 1912, 1923, 1925, 1927, 1932, 1933, 1939, 1941, 1946, 1955, 1957, 1960, 1964, 1968, 1975, 1999, 2012, 2015. Accessed August 6, 2019. https://www.historicaerials.com/viewer.

Norris, R.M., and R.W. Webb, 1990. Geology of California (2nd edition). New York, NY: John Wiley & Sons.

O’Neil, S. 2002. The Acjachemen in the Franciscan Mission System: Demographic Collapse and Social Change.

Master’s thesis, Department of Anthropology, California State University, Fullerton.

Pasadena Independent. 1964. “2-Billion Gallon Tunnel Proposed for Area’s Water.” Newspapers.com: Pasadena Independent (Pasadena, California). September 15, 1964, pg. 15.

Pasadena Independent. 1968. “Glendora 6-day Fire Contained.” Newspapers.com: Pasadena Independent.

August 29, 1968, pg. 26.

Price, R.L. 2008. Glendora (Postcard History Series). Arcadia Publishing. Charleston, South Carolina.

Price, R.L. 2012. Stories of Old Glendora. American Chronicles: A History Press Series. Charleston, South Carolina.

SBCS (San Bernardino County Sun). 1936a. “Work Begun on Aqueduct Project Through Valley.” Newspapers.com:

San Bernardino County Sun (San Bernardino, California). March 27, 1936, pg. 12.

SBCS. 1936b. “New Districts May Share Water of Colorado River.” Newspapers.com: San Bernardino County Sun.

August 11, 1936, pg. 19.

SBCS. 1946. “21 Surrender After ‘Mutiny’ of Glendora Conscientious Objectors.” Newspapers.com: San Bernardino County Sun. May 31, 1946, pg. 2.

SBCS. 1963. “MWD Directors Vote Today on Foothill Feeder Line.” Newspapers.com: San Bernardino County Sun.

June 25, 1963, pg. 21.

SBCS. 1965. “MWD Awards $22 Million Tunnel Job.” Newspapers.com: San Bernardino County Sun.October 20, 1965.

SFE (San Francisco Examiner). 1878. “Appointments by the President and Confirmations by the Senate.” Newspapers.com: San Francisco Examiner. February 21, 1878, pg. 3.

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Society of Vertebrate Paleontology (SVP). 2010. Standard Procedures for the Assessment and Mitigation of Adverse Impacts to Paleontological Resources. 11 p. Available; http://vertpaleo.org/PDFS/68/68c554bb-86f1-442f-a0dc-25299762d36c.pdf.

Spitzzeri, Paul. 2019. “La La Landscapes: The Rancho Los Alisos of Judge Charles Silent, Glendora.” The Homestead Blog. May 13, 2019. Accessed August 15, 2019. https://homesteadmuseum.wordpress.com/2019/05/13/la-la-landscapes-the-rancho-los-alisos-of-judgecharles-silent-glendora/ UCSB (University of California, Santa Barbra). 2019. Historic Aerial Photographs of Silent Ranch property, Glendora, CA dating from 1927, 1933, 1934, 1938, 1953, 1956, 1960, 1968, and 1976. Map & Imagery Laboratory (MIL) UCSB Library, Accessed August 6, 2019. http://mil.library.ucsb.edu/ap_indexes/FrameFinder.

USFS (US Forest Service). 1975. “Concrete Crib Check Dams.” Engineering Technical Information System: Field Notes. Volume 7, Number 6, revised. Published June 1975, accessed August 9, 2019. https://www.fs.fed.us/t-d/pubs/pdfpubs/pdf75713806/pdf75713806.pdf USGS (United States Geological Survey). 2019. Historic Topographical Maps of Glendora area, dating from 1894, 1897, 1897, 1901, 1904, 1925, 1927, 1933, 1939, , 1953, 1966, 1972, 1995. USGS Historical Topographic Map Explorer, ESRI and USGS. Accessed August 6, 2019. http://historicalmaps.arcgis.com/usgs/
Valley News. 1956. “Girl Scouts Plant Seedlings at Campsite Near Glendora” Newspapers.com: Valley News (Van Nuys, California). January 12, 1956, pg. 55.

Wallace, W.J. 1955. A Suggested Chronology for Southern California Coastal Archaeology. Southwestern Journal of Anthropology 11(3):214–230.

Wallace, W.J. 1978. Post-Pleistocene Archaeology, 9000 to 2000 B.C. In California, edited by Robert F. Heizer, pp. 25–36. Handbook of North American Indians, Vol. 8, William G. Sturtevant, general editor, Smithsonian Institution, Washington D.C.

Warren, C.N. 1968. “Cultural Tradition and Ecological Adaptation on the Southern California Coast.” In Archaic Prehistory in the Western United States, edited by C. Irwin-Williams, 1–14. Portales, New Mexico: Eastern New Mexico University Contributions in Anthropology.

Waugh, J.C. 2003. On the Brink of Civil War: The Compromise of 1850 and How It Changed the Course of American History. Wilmington, Delaware: Scholarly Resources Inc.

WDPJ (Wilmington Daily Press Journal.) 1936. “Metropolitan Aqueduct Has World’s Biggest Pipeline.” Newspapers.com: Wilmington Daily Press Journal (Wilmington, California). June 4, 1946, pg. 3.

Weymouth, F.E. 1939. History and First Annual Report for the period ending June 30, 1938. Los Angeles:

Metropolitan Water District of Southern California.

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Appendix A
Preparer’s Qualifications
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Kate Kaiser, MSHP
Architectural Historian
Kate Kaiser is an architectural historian with 7 years’ professional experience as a cultural resource manager specializing in California Environmental Quality Act (CEQA) compliance, National Historic Preservation Act Section 106 compliance, reconnaissance and intensive level surveys, archival research, cultural landscapes, and GIS.

Ms. Kaiser meets the Secretary of the Interior’s Professional Qualification Standards for both architectural history and archaeology.

In addition, Ms. Kaiser has worked as an archaeological technician for the National Park Service and USDA Forest Service. She has worked with federal, private, and local organizations to manage multidisciplinary transportation projects, park-wide inventories, and federal land management projects.

Project Experience
Development

14545 Lanark Street Project, Panorama City, City of Los Angeles, California. Kaiser served as architectural historian and co-author of the cultural resources technical report for the 14545 Lanark Street Project.

The report included conducting a CHRIS record search, reviewing permits held by the City of Angeles, archival research, historical context development, developing building and structure descriptions, and historical significance evaluations for the former Los Angeles County Social Services office in Panorama City. The project proposed to demolish the Social Services office and redevelop the property into 120 studios, one-, two-, and three-bedroom apartments serving low-income individuals and families.

Cultural Resources Technical Report for the City of Irwindale Speculative Concrete Tilt-Up Building Project.

Irwindale, Los Angeles County, California. Kaiser served as architectural historian and author of the cultural resources technical report for the City of Irwindale Speculative Concrete Tilt-Up Building Project. The report included conducting a CHRIS record search, reviewing permits held by the City of Irwindale, archival research, historical context development, developing building and structure descriptions, and historical significance evaluations for two buildings and thirteen structures at a hollow-core concrete panel manufacturer in southeast Irwindale. The project proposed to demolish all buildings and structures in the project site and construct a 528 710 s.f., tilt-up concrete warehouse on the parcel. All four buildings were determined ineligible for listing in the National Register of Historic Places (NRHP), the California Register of Historical Resources (CRHR), or as a City of Irwindale Historic Resource.

Historical Resource Assessment for 1230 North Ogden Drive, City of West Hollywood, Los Angeles County, California. Served as architectural historian and author of the historic resource assessment for four residential buildings on the 1230 North Ogden Drive parcel in West Hollywood. Report included conducting a record search, Education
University of Oregon
MS, Historic Preservation, 2017
Boston University
BA, Archaeology, 2009
Professional Affiliations
Association for Preservation
Technology – Southwest
California Preservation Foundation
Vernacular Architecture Forum
Kate Kaiser
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coordinating with the City of West Hollywood for building permits, developing the building description, archival research, historical context development, historical significance evaluations, and California DPR form production for the four buildings. The historical resource assessment report fulfills City requirements during the development permit application process. All four buildings were determined ineligible for listing in the NRHP or CRHR.

Education
Campus-wide Historic Context Statement for California State University Long Beach, City of Long Beach, Los Angeles County, California. Served as architectural historian and co-author of the historic context statement report analyzing the effect of master architect Edward Killingsworth on the development of the campus. Preparation of the historic context statement involved extensive archival research, historic context development, in-person interviews of architects who worked on-campus, review of CSU Long Beach building and landscape records, and coordination with local heritage group, Long Beach Heritage.

Historic Resource Evaluation Report for the Housing Expansion Phase I – Parkside North Housing Project, California State University Long Beach, City of Long Beach, Los Angeles County, California. Served as architectural historian and author of the Historic Resource Evaluation Report for the Housing and Residential Life (HRL) building in support of the Parkside North Housing Project. The report included conducting a CHRIS record search, reviewing permits, archival research, historical context development, developing building and structure descriptions, and a historical significance evaluation for the HRL office building. The project proposed to demolish the HRL building, and replace it with a new student housing building, adding 476 student dormitory beds to the CSU Long Beach campus. While the existing HRL building proposed for demolition was not yet 50 years old, it was designed by local master architect Edward Killingsworth and required consideration as a potential historical resource under CEQA. Dudek determined that the HRL building was not eligible under all applicable designation criteria due to a lack of significant associations and compromised integrity.

Healthcare
Kaiser Permanente Los Angeles Specialty Medical Center Project, Los Angeles, Los Angeles County, California.

Served as architectural historian and author of the Historical Resource Assessment for the Kaiser Permanente Los Angeles Specialty Medical Center at 755-765 W. College Street in Los Angeles. Preparation of the report involved extensive archival research, reconnaissance level fieldwork, historic context development, building development descriptions, historical significance evaluations for buildings greater than 45 years in age, and DPR forms for the medical center buildings and structures that are proposed for demolition as part of the multiphase project. As a result of the evaluations, all buildings were found not eligible for designation under all applicable national, state, and local designation criteria and integrity requirements.

Kaiser Permanente Los Angeles Medical Center Project, Los Angeles, Los Angeles County, California. Served as architectural historian and co-author of the Draft EIR Cultural Resources Chapter and the author of the Cultural Resources Report Appendix. Preparation of the report involved extensive archival research, reconnaissance level fieldwork, historic context development, building development descriptions, historical significance evaluations, and DPR forms for six buildings greater than 45 years in age that are proposed for demolition as part of the multiphase project. As a result of the evaluations, all buildings proposed for demolition were found not eligible for designation under all applicable national, state, and local designation criteria and integrity requirements. DEIR chapter also analyzed potential indirect impacts on two other National Register listed or eligible sites: the Aline Barnsdall Complex and the Hollywood Presbyterian Medical Center.

Municipal
Northside Specific Plan Draft EIR, City of Riverside, Riverside County, California (ongoing). Kaiser served as architectural historian and author of the Draft EIR Cultural Resources Chapter for the developed for City of Riverside’s Northside Specific Plan. The cultural resource chapter involved conducting a record search and documenting results, Item #8. Page 931
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developing a historic context for the Specific Plan Area, and developing an impacts analysis and mitigation measures for the future development of the Northside Specific Plan Area. The Northside Specific Plan proposed changes to zoning and the potential redevelopment of a site containing a historic adobe.

LADWP City Trunkline South Project, Los Angeles Department of Water and Power, California (ongoing). Served as architectural historian and author of the Cultural Resources Technical Report for the City Trunkline South Project.

Preparation of the report involved site recordation, extensive archival research, historic context development, building development descriptions, historical significance evaluations, and State of California Department of Parks and Recreation Series 523 forms (DPR forms) for each building of the project. The project proposed to replace sections of the pipeline in located in the Coldwater Canyon Road area of the San Fernando Valley. The report analyzed the vibration effects of pipeline replacement and pipe-jacking practices expected as part of the Trunkline project.

LADWP Western District Yards Project, Los Angeles Department of Water and Power, California. Served as architectural historian and author of the Cultural Resources Technical Report for the Wester District Yards Rehabilitation Project.

Preparation of the report involved site recordation, extensive archival research, historic context development, building development descriptions, historical significance evaluations, and State of California Department of Parks and Recreation Series 523 forms (DPR forms) for each building of the project. The project proposed to demolish 11 buildings and structures constructed between 1946 and 2007. This resource had been previously evaluated and designated eligible for the CRHR under Criterion 1 and 3, however this evaluation was outdated and a revised evaluation determined that the property was no longer eligible for national, state, or local listing.

LADWP Valley Generating Station Project, Los Angeles Department of Water and Power, California. Served as architectural historian and author of the Cultural Resources Technical Report for the Valley Generating Station Project. Preparation of the report involved site recordation, extensive archival research, historic context development, engineering feature development descriptions, historical significance evaluations, and State of California Department of Parks and Recreation Series 523 forms (DPR forms) for each building of the project. The project proposed to remove the 1953 steam generating plant, as well as the four stacks, SPRR rail spur, and underground fuel tanks.

LACSD Gardena Pumping Station Project, Sanitation Districts of Los Angeles County, Gardena, California. Served as architectural historian and author of the Cultural Resources Technical Report for the Gardena Pumping Project.

Preparation of the report involved site recordation, extensive archival research, historic context development, engineering feature development descriptions, historical significance evaluations, and State of California Department of Parks and Recreation Series 523 forms (DPR forms) for each building of the project. The project proposed to remove the 1929 and 1960 pumping plant above and below-ground structures, as well as two adjacent parcels containing commercial buildings (1954, 1957) and replace them with a larger capacity pumping plant facility.

Phillips 66 and Kinder Morgan Relocation Project, Berths 150-151, Marine Oil Terminal Engineering and Maintenance Standards (MOTEMS), Port of Los Angeles, California. Served as architectural historian and coauthor of the Updated Historical Resources Evaluation Report for the Phillips 66 and Kinder Morgan Relocation Project. Preparation of the report involved reviewing previous evaluations for Union Oil Terminal Berths 150-151 and writing an updated significance evaluation. The project proposed to remove and replace the original wharfs with new concrete loading platform, mooring and breasting dolphins, access ramps, catwalks, and an underwater bulkhead. It also proposed the construction of new topside and piping components connecting the new platform to existing pipes in the backlands.

Globemaster Corridor Specific Plan, City of Long Beach, Los Angeles County, California. Served as architectural historian and author of the Draft EIR-EIS Cultural Resources Chapter for the Globemaster Corridor Specific Plan Item #8. Page 932
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(GCSP) project. The project proposed to implement the GCSP, a planning and regulatory framework for redevelopment of an area adjacent to the Long Beach Airport and the surrounding residential and business community which includes rezoning portions of the GCSP area, and a mobility plan that implements new streets and pedestrian connectors. Since the GCSP does not directly propose changes to the buildings or structures in the Plan area, the cultural resources report takes a programmatic overview and offers potential impacts analysis and mitigation measures for future development.

LADWP De Soto Tanks Project, Los Angeles Department of Water and Power, California. Served as architectural historian and author of the Historic Properties Identification Report for the De Soto Tanks EIR. Preparation of the report involved site recordation, extensive archival research, historic context development, engineering feature development descriptions, historical significance evaluations, and State of California Department of Parks and Recreation Series 523 forms (DPR forms) for each building of the project. The project proposed to remove the 1941 reservoir and associated buildings, and replace them with two modern underground storage tanks, as well as connections to the LADWP Rinaldi Trunk Line and De Soto Trunk Line.

LADWP Tujunga Spreading Grounds Enhancement, Los Angeles Department of Water and Power, California.

Served as architectural historian and author of the cultural resources report CEQA-Plus Project. Preparation of the report involved site recordation, extensive archival research, historic context development, engineering feature development descriptions, historical significance evaluations, and State of California Department of Parks and Recreation Series 523 forms (DPR forms) for each building of the project. The evaluation found the property ineligible under all NRHP, CRHR, and Los Angeles Historic-Cultural Monuments designation criteria. The project proposed to modify a U.S. Army Corps of Engineer-owned flood control channel to divert more flood water from the Tujunga Flood Control Channel into the Tujunga Spreading Grounds.

State
Judicial Council of California Historical Resource Evaluation Report for the Stanley Mosk Courthouse, City of Los Angeles, Los Angeles County, California. Served as architectural historian and author of the historical resource evaluation report. Preparation of the report involved extensive archival research, interior and exterior survey fieldwork, historic context development, material descriptions, historical significance evaluations, and DPR forms for the Stanley Mosk Courthouse. Dudek was retained by the Judicial Council of California (JCC) to prepare an evaluation of the Stanley Mosk Los Angeles County Courthouse building, located at 111 N. Hill Street in the City of Los Angeles, California. To comply with Public Resources Code Section 5024(b), the JCC must submit to the State Historic Preservation Officer (SHPO) an inventory of all structures over 50 years of age under the JCC’s jurisdiction that are listed in or that may be eligible for inclusion in the National Register of Historic Places (NRHP), or registered or that may be eligible for registration as a California Historical Landmark (CHL), The Stanley Mosk Courthouse was found eligible for designation for the NRHP, CHL, CRHR, and Los Angeles Historic Cultural Monument list under Criterion A/1 and C/3.

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Kathryn Haley, MA
Senior Architectural Historian
Kathryn Haley is a senior architectural historian with over 15 years of professional experience in historic/cultural resource management.

Ms. Haley has worked on a wide variety of projects involving historic research, field inventory, and site assessment conducted for compliance with Section 106, NEPA, and CEQA. Ms. Haley specializes in California Register of Historical Resources (CRHR), the National Register of Historic Places (NRHP), evaluations of built environment resources, including water management structures (levees, canals, dams, ditches), buildings (residential, industrial, and commercial), and linear resources (railroad alignments, roads, and bridges). She specializes in managing large-scale surveys of built environment resources including historic district evaluations. She has prepared numerous Historic Resources Evaluation Reports (HRERs) and Historic Property Survey Reports (HPSRs) for the California Department of Transportation (Caltrans). Ms. Haley also worked on the California High-Speed Rail, San Jose to Merced, and Central Valley Wye Project Sections; leading the built environment survey, conducting property specific research, preparing the Draft Historic Architectural Survey Report (HASR) as well as co-authoring the environmental section for Cultural Resources.

She meets the Secretary of the Interior’s Professional Qualification Standards for historian and architectural historian. Ms. Haley has also assisted in preparation of Historic Properties Inspection Reports (condition assessments) under the direction of the Naval Facilities Engineering Command (NAVFAC) in accordance with Section 106 and Section 110 of the National Historic Preservation Act. Moreover, Ms. Haley has served as project manager, coordinator, historian, and researcher for a wide variety of project. She is also experienced in the preparation for National Register nominations, as well as, Historic American Building Survey (HABS), Historic American Engineering Record (HAER), and Historic American Landscape Survey (HALS) documents.

Previous Project Experience
Transportation – Roads, Bridges, Highways, and Rail
California High-Speed Rail (CHSR) from San Jose to Merced and Central Valley Wye Project Sections—California High-Speed Rail Authority/Parsons Transportation Group, Various Counties in California (2010 to 2018). For several years, Ms. Haley served as lead historian and project coordinator for architectural history for the San Jose Merced and Central Valley Wye Project Sections. She led built environment field surveys, property specific historical research, co-wrote technical reports, and assisted in preparing the EIR/EIS cultural resources section.

All work was conducted according to stipulations in the programmatic agreement written specifically for the project and in coordination with the California High Speed Rail Authority. While working on these project sections Ms. Haley participated in surveying more than 1000 buildings. She played a key role in managing the survey data, and evaluating built environment resources under NRHP and CRHR Criteria, as well as ensuring the proper documentation of locally designated CEQA historical resources.

Education
California State University,
Sacramento
MA, Public History, 2004
California State University,
Sacramento
BA, History, 2001
Professional Affiliations
California Council for the Promotion
of History (former Treasurer)
California Preservation Foundation
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Interstate 80 (I-80)/I-680 Interchange Projects—Solano County Transportation Authority, Solano County, California (2009). Ms. Haley conducted a field survey and contributed to NRHP and CRHR evaluations of historic architectural resources located in the I-80/I-680/State Route 12 (SR-12) interchange project area. More than 200 historic architectural resources were identified in the project area, including two historic districts. The Suisun City Historic District was identified as part of this project and consisted of 95 contributing buildings built within the period of significance, 1880-1934. The district comprised residential and commercial buildings constructed in a wide range of architectural styles, including Queen Anne and Craftsman bungalows, as well as late 19th century and early 20th century Revival styles. The Village of Cordelia Historic District, also located in the project area, was previously identified as eligible for the NRHP in 1989. The historic district was reevaluated as part of this project because several of the contributing buildings had been destroyed and fallen into disrepair. The overall integrity of the district, contributors and non-contributors, as well as district boundaries were reassessed and documented.

All work was conducted according to Caltrans guidelines for compliance with Section 106.

Bayview/Hunters Point Transportation Improvements Project—City and County of San Francisco and Caltrans, California (2007). Ms. Haley severed lead investigator for historic architectural resources. She conducted fieldwork and prepared documentation identifying and evaluating historic properties in the Bayview/Hunters Point project area for Section 106 compliance. Ms. Haley prepared a HPSR and HRER identifying and evaluating historic properties in accordance with Caltrans guidelines.

Healdsburg Avenue Bridge NEPA/CEQA Compliance—City of Healdsburg/Omni Means, California (2012). As lead historian Ms. Haley conducted a field survey and wrote the constraints analysis for historic resources. The project studied different alternatives in replacing and rehabilitating the historic Healdsburg Avenue Bridge, which is listed in the NRHP. She also prepared the HSPR, HRER and assisted in preparing the FOE for the project.

Parks/Trail/Bicycle Path/Recreation
East Bay Greenway (Lake Merritt BART to South Hayward BART), HNTB, Alameda CTC, Oakland, San Leandro, Hayward, and Alameda County, California (2017 to 2018). Served as technical lead for architectural history.

Prepared HRER for Caltrans as part of the CEQA/NEPA documentation for a visionary 16-mile, multimodal trail facility (rail to trail/rail with trail) connecting seven Bay Area Rapid Transit (BART) stations adjacent to the UPRR Oakland Subdivision from Oakland to Hayward. The project objectives include improvement of bicycle and pedestrian network connectivity; access to schools, downtown destinations, and activity centers; and development of a multimodal transportation system. Ms. Haley also prepared a Finding of Effect (FOE) document in support of a No Adverse Effect Finding to historically significant properties identified in the HRER.

Mitigation Implementation
Tower Bridge Pedestrian/Bikeway Improvement Project—City of Sacramento/Parsons Brinkerhoff, California (2007).

Ms. Haley conducted archival research and prepared text for interpretative display kiosks outlining the history of the Tower Bridge, which is listed in the NRHP. The interpretive kiosks were created in compliance with Section 106 to mitigate changes to the Tower Bridge resulting from the expansion of the structure’s pedestrian walkways.

Doyle Drive and Presidio Mitigation Project for HABS, HAER, and HALS Documentation—Parsons Brinkerhoff, San Francisco, California (2010 to 2014). This work included documenting several contributing historic buildings, structures, and landscape features located within the Presidio of San Francisco National Historic Landmark (NHL) District. This recordation was required under Section 106 of the NHPA to mitigate the adverse effects of the Doyle Drive replacement project. Doyle Drive is the southern access route to the Golden Gate Bridge. Construction activities related to the project will result in the demolition of historic resources that contribute to the NHL district.

Ms. Haley served as project coordinator, assistant historian, researcher, and co-author for compliance documents prepared for this project.

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Hallbom Ranch Mitigation—Placer County Water Agency, Auburn, California. Assistant Historian (2006). Ms. Haley conducted research and assisted in production of a brochure that documented the history of the property. The brochure was produced as part of mitigating impacts to Hallbom Ranch due project construction on the historically significant property. The mitigation was required as part of CEQA compliance.

Feather River CEQA/NEPA Compliance, Mitigation for Adverse Effects to the Sutter Butte Canal —Sutter Butte Flood Control Agency (SBFCA), Butte and Sutter Counties, California (2016). As built environment lead, Ms. Haley worked with the USACE to establish efficient and appropriate mitigation for the burial of the Sutter Butte Canal Haselbusch Headgate, which was determined eligible for listing in the NRHP and CRHR as part of the cultural resources inventory and evaluation efforts for this project. To mitigate the adverse effect to the resource, an interpretative program was established in consultation with the USACE, SHPO, and SBFCA. Ms. Haley lead the effort to produce an interpretive brochure and exhibit that explained the history of the Sutter Butte Canal Haselbusch Headgate. The brochures were distributed to local libraries and archives in Sutter and Butte Counties.

The exhibit is part of the Butte County Historical Museum in Oroville, CA.

Ports and Harbors
Historic Initiative Inventory and Conservation—Port of Los Angeles, California (2006 to 2007) Ms. Haley assisted the Port of Los Angeles with establishing an archival repository to house historic documents by advising the Port on all aspects of the proposed archival facility. As project manager and lead archivist, she conducted a records inventory, facilitated immediate preservation and conservation of historic materials, and helped establish policy and procedures for the archives.

Architectural Survey and Evaluation of Signal Street Properties—Port of Los Angeles, California (2007). Ms. Haley prepared an inventory and evaluation report for six historic era properties located in an area that LAHD was planning on redeveloping. The purpose of the report was to evaluate the properties under NHPR, CRHR, and the criteria set forth in the City of Los Angeles Heritage Ordinance to see if they were eligible for listing. Ms. Haley completed this work during the planning phase of the redevelopment project. Five of the six buildings were found eligible for listing in the NRHP, CRHR, and as Los Angeles Historic Cultural Monuments.

Development
Section 106 Compliance for the Sixth Street Streetscape West Project—Harris and Associates and City of Gilroy, California (2008). Ms. Haley served as project manager and lead architectural historian prepared a recommendations report for Section 106 compliance for streetscape improvements within the City’s downtown historic district.

Military
Naval Air Station Alameda, Historic Properties Inspection Report and Draft NRHP Nomination—Naval Facilities Engineering Command, Alameda, California (2008). Ms. Haley served as assistant historian in the preparation of historic properties inspection reports and a NRHP nomination for the Naval Air Station Alameda Historic District under the direction of the Naval Facilities Engineering Command, in accordance with Section 106 and Section 110 of the NHPA. Tasks included conducting research, a field survey, and written condition assessments of the contributing buildings and structures located within the historic districts.

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Appendix B
Confidential Records Search Results
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Appendix C
DPR forms
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P1. Other Identifier: MWD Upper Feeder pipeline (segment) DPR 523A (9/2013) *Required information
State of California  The Resources Agency Primary #
DEPARTMENT OF PARKS AND RECREATION HRI #
PRIMARY RECORD Trinomial
NRHP Status Code 3D
Other Listings
Review Code Reviewer Date
*P2. Location:  Not for Publication  Unrestricted
*a. County Los Angeles and (P2c, P2e, and P2b or P2d. Attach a Location Map as necessary.) *b. USGS 7.5' Quad Glendora Date 1995 T 1N; R 10W; SE ¼ of SE ¼ of Sec 24; San Bernardino B.M. c. Address 950 Silent Ranch Drive City Glendora Zip 91741 d. UTM: (Give more than one for large and/or linear resources) Zone 11S , 419565 mE/ 3779300 mN; Zone 11S , 419460 mE/ 3779418 mN; Zone 11S , 419378 mE/ 3779600 mN e. Other Locational Data: (e.g., parcel #, directions to resource, elevation, decimal degrees, etc., as appropriate) This 1170 foot long segment of the MWD Upper Feeder pipeline is within parcel 8684-045- 004, on 950 North Silent Ranch Drive, at the northern terminus of Grand Avenue in the City of Glendora. The entire Monrovia No. 1 tunnel extends 7,868 feet from portal to portal.

The entire Upper Feeder pipeline extends from Lake Matthews, (See Continuation Sheet) *P3a. Description: (Describe resource and its major elements. Include design, materials, condition, alterations, size, setting, and boundaries) The Monrovia No. 1 tunnel and hatch structure are components of a larger water conveyance system called the Upper Feeder pipeline, completed in 1939, owned and operated by the Metropolitan Water District of Southern California (MWD), and operating today as an active utility. The Upper Feeder was designed and constructed concurrently with the Colorado River Aqueduct as part of the distribution system, which furnished water to participating cities for distribution b local municipal water departments. (See Continuation Sheet) *P3b. Resource Attributes: (List attributes and codes) AH6 – water conveyance system *P4. Resources Present:  Building
 Structure  Object  Site  District 
Element of District  Other (Isolates, etc.)
P5b. Description of Photo: (view, date,
accession #) tunnel hatch,
looking northwest, (IMG_1339)
*P6. Date Constructed/Age and
Source: Historic  Prehistoric 
Both
1937 (Weymouth 1939)
*P7. Owner and Address:

Metropolitan Water District of
Southern California
700 N. Alameda Street
Los Angeles, CA 90012
*P8. Recorded by: (Name, affiliation,
and address) Kate Kaiser, MSHP
DUDEK, 38 N Marengo Ave
Pasadena, CA 91101
*P9. Date Recorded: 8/1/2019
*P10. Survey Type: pedestrian
*P11. Report Citation: Dudek. 2019. Historical Resources Technical Report for Silent Ranch Hillside Subdivision Project. Prepared for City of Glendora Planning Department. *Attachments: NONE Location Map Continuation Sheet Building, Structure, and Object Record Archaeological Record District Record Linear Feature Record Milling Station Record Rock Art Record Artifact Record Photograph Record  Other (List):

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*Map Name: Glendora, Calif. *Scale: 1:24,000 *Date of map: __1995___________ DPR 523J (Rev. 1/1995)(Word 9/2013) *Required information State of California  Natural Resources Agency Primary # DEPARTMENT OF PARKS AND RECREATION HRI#
LOCATION MAP Trinomial
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*Resource Name or # (Assigned by recorder) Monrovia No. 1 tunnel (segment) *NRHP Status Code 3D

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DPR 523B (9/2013) *Required information
State of California  The Resources Agency Primary #
DEPARTMENT OF PARKS AND RECREATION HRI#

BUILDING, STRUCTURE, AND OBJECT RECORD
B1. Historic Name: Monrovia No. 1 tunnel (segment)
B2. Common Name: Monrovia No. 1 tunnel (segment); MWD Upper Feeder Pipeline (segment) B3. Original Use: water conveyance system B4. Present Use: water conveyance system *B5. Architectural Style: utilitarian
*B6. Construction History: (See Continuation Sheet)
*B7. Moved? No Yes Unknown Date: Original Location:
*B8. Related Features:

Same parcel: USFS/LACFCD Crib Dams
Same parcel: Rancho Los Alisos/Camp Aventura
B9 a. Engineer: Robert Bernard Diemer (1888-1966)
b. Builder: Metropolitan Water District of Southern California *B10. Significance: Theme Municipal Water Utility Development Area Southern California: greater metropolitan Los Angeles area, Inland Empire, San Diego County
Period of Significance 1931-1941 Property Type Water Conveyance System Applicable Criteria A/1/1
(See Continuation Sheet)
B11. Additional Resource Attributes: (List attributes and codes) *B12. References:(See Continuation Sheet)
B13. Remarks: The Monrovia No. 1 tunnel and hatch are recommended eligible under Criterion A/1/1 as a component of the MWD Upper Feeder pipeline, for the period 1931-1941 for representing a critical component of a larger water infrastructure, the MWD Upper Feeder pipeline. The MWD Upper Feeder pipeline was instrumental to addressing the water needs of the greater metropolitan area of Los Angeles, and was an enabling force for the intensive economic and residential development of Southern California. The Monrovia No. 1 tunnel and hatch was evaluated in accordance with Section 15064.5(a) (2)‐(3) of the California Environmental Quality Act (CEQA) Guidelines using the criteria outlined in Section 5024.1 of the California Resources Code, and it appears to be a historical resource for the purposes of CEQA and a historical property for the purposes of Section 106 of the NHPA (36 CFR Part 800). Dudek recommends this
resource be assigned a California Historical
Resource Status Code of 3D (appears eligible for
NR as a contributor to a NR eligible district
through survey evaluation), 3CD (appears eligible
for CR as a contributor to a CR eligible district
through a survey evaluation), and 5S3 (appears to
be individually eligible for local listing or
designation through survey evaluation).
*B14. Evaluator: Kate Kaiser, MSHP
*Date of Evaluation: 8/26/2019
(This space reserved for official comments.)
(Sketch Map with north arrow required.)
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P2e. Other Locational Data (continued): Riverside to San Rafael Tunnel terminating in Glendale. Elevation: 980 to 1277 feet amsl.

P3a. Description (continued): MWD Upper Feeder Pipeline segment: Monrovia No. 1 tunnel (1937)
The MWD Upper Feeder Pipeline segment: Monrovia No. 1 tunnel is a subterranean structure that transects the proposed project APE from a point due east of the 950 Silent Ranch Drive main house building to a point northeast of the 950 Silent Ranch Drive main house building, in the eastern section of the proposed project APE. No portion of the Monrovia No. 1 tunnel was accessible for survey, due to it being underground. Historical MWD source document that entirety of the 41.6 miles from Lake Matthews to the east portal of Monrovia No. 1 tunnel was constructed of welded steel and precast concrete pipe. The Monrovia No. 1 tunnel extended 7,868 feet from portal to portal, and was a concrete lined pressure tunnel in rock substrate, and was 10 feet in diameter, with light supper of steel ribs and timber lagging occasionally placed as-needed (Weymouth 1939: 266-269).

The original subsurface section of the MWD Upper Feeder was constructed between 1936 and 1939; however, the asbestos lid does not appear to be of 1930s construction. The hatch structure is labeled with stenciled paint on the top and side with “2256-93.” Figure 1. MWD hatch, looking northwest (IMG_1339)
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Identified Alterations
No permits were available from the Metropolitan Water District of the City of Glendora for the infrastructure related to the Upper Feeder. No observed alterations were noted in the course of survey.

B6. Construction History (continued):

MWD’s Colorado River Aqueduct construction project, which lasted nearly 10 years, erected four dams, five pumping plants, 92 miles of tunnels, 63 miles of concrete lined canals, 55 miles of concrete conduit, and 29 miles of siphon from Lake Havasu to Lake Matthews in Riverside. Once in the reservoir at Lake Matthews, water was dispensed to the member cities through the distribution system. Both the aqueduct and distribution system were some of the largest public works projects in southern California during the Great Depression (Desert Sun 1938; LAT 1934; Weymouth 1939).

Concurrent to the erection of the 242-mile aqueduct was the distribution system that lead from the aqueduct terminus to each of the participating cities. The distribution system consisted of the Morris Dam and Reservoir, 16 miles of tunnel, and 134 miles of pipelines to carry water to each of the thirteen cities (Figure 8). Two portions of this distribution feeder system are located in the proposed project APE. North of the APE, the Morris Dam was erected between 1932 and 1934 in the San Gabriel River Basin. It was originally owned by the City of Pasadena, but sold in 1935 to MWD. The other portion is the Upper Feeder distribution line, a 65-mile distribution line extending from Lake Matthews to the San Rafael Tunnel. The upper feeder consisted of sections of underground 10-foot diameter tunnel lined with concrete, and large diameter precast concrete or welded steel plate pipes. In 1935, orchard owners north of Glendora, Claremont, La Verne, Pomona, and San Dimas conferred with MWD and attempted to negotiate for surplus water in exchange for allowing the pipeline through their lands. In 1936, a new MWD water district inducted the cities of Ontario, Upland, Claremont, San Dimas, Glendora, Pomona, and La Verne (Argus 1935; Creason 2015; Hinds 1935; SBSC 1936a; Weymouth 1939; WDPJ 1936).

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Figure 2. Colorado River Aqueduct Map, The Metropolitan Water District of Southern California. (Special Collections, Honnold Mudd Library, Claremont Colleges Library system)
Construction of a 30-mile section of the Upper Feeder pipeline began in 1936 near the Lake Matthews Reservoir, and extended north to Fontana then west to just below Morris Dam Reservoir north of Glendora in the Angeles National Forest. From Morris Reservoir, the feeder continued west in a separate segment through the Monrovia No. 3 through 4 tunnels to the San Rafael Tunnel, to Glendale. In Glendora, the Upper Feeder pipeline stayed at the base of the San Gabriel Range foothills, before crossing diagonally through the foothills northwest towards Morris Dam. A right-of-way was obtained in 1935 for the section through the Silent Estate. This location was chosen partly to avoid costly purchases of rights-of-way, which would be needed in densely settled urban areas. The Silent Ranch Estate right of way was for part of Monrovia No. 1, a tunnel extending 7,868 feet from east portal to west portal, exiting above the San Gabriel River canyon. The tunnel work was completed by West Construction Company in February 1937. Construction of the Upper Feeder pipeline as a whole was interrupted by the major storm and subsequent flood damage in February 1938; however, work on the feeder was completed later that year.

In 1939, the distribution system was connected to the Lake Matthews Dam but the main Colorado River Aqueduct was not completed until 1941. In June 1941, the aqueduct and distribution system finally went into operation and on June 20, 1941, water finally reached the City of Pasadena (Argus 1935; Creason 2015; Hinds 1935; LAT 1936; SBSC 1936a, 1936b; Weymouth 1939; WDPJ 1936).

Associated Engineer: Robert Bernard Diemer (1888-1966)
R.B. Diemer was born in 1888 in Palmyra Missouri, and graduated from the University of Missouri with a Bachelor’s of Science in engineering at 23. Like many young engineers who graduated in the 1910s, Diemer began his career with the Reclamation Service (later Bureau of Reclamation), working on the North Platte Project (1903-1927), an irrigation project in Wyoming and Nebraska. In 1929, he left the Reclamation Service to work for the newly formed Metropolitan Water District (MWD), with other former Reclamation Service engineer Frank E. Weymouth. In 1930, Diemer became the distribution division engineer on MWD’s Colorado River Aqueduct project, responsible for all 150+ miles of distribution system Item #8. Page 949
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west of Lake Matthews. Diemer remained in career at the MWD, and ion 1950 became assistant general manager. In 1952, he became MWD’s general manager and chief engineer and served in this position until he retired in 1961 (Hager 2015).

B10. Significance (continued): NRHP/CRHR Statement of Significance Criterion A/1: That are associated with events that have made a significant contribution to the broad patterns of our history.

The section of Upper Feeder pipeline within the study area is subterranean Monrovia No. 1 tunnel with only one visible, above-ground structure: the concrete access hatch.

Monrovia No. 1 tunnel is an underground pipeline and critical segment of the MWD Upper Feeder pipeline, the first multi-city municipal water distribution system of its kind in the region. The entire Upper Feeder pipeline system was designed in 1931, contract for the Monrovia No. 1 tunnel was awarded to West Construction Company in 1934, the rightof-way easement was acquired in 1935 through the Silent Ranch Estate, and the Monrovia No. 1 tunnel was completed in 1937. Water first flowed through the distribution system in 1941. No date of construction could be ascertained for this hatch; however, it is assumed that the construction date is concurrent with the Monrovia No. 1 tunnel: 1937.

Both Monrovia No.1 tunnel and the access hatch are components of the larger Upper Feeder pipeline and distribution system for the Colorado River Aqueduct. The entire distribution the Upper Feeder pipeline belongs to extends 150-miles and serves participating cities in the greater metropolitan Los Angeles area, the Inland Empire, San Diego County, and other Southern California areas. The Upper Feeder pipeline is the first segment of the distribution system for the MWD Colorado River Aqueduct, extending 60 miles from the Colorado River Aqueduct’s western terminus at Lake Matthews to the San Rafael tunnel between Pasadena and Glendale. The construction of the distribution system and Upper Feeder pipeline c made a significant contribution to the board pattern of history as part of the transportation and distribution of Colorado River water, an enabling force for the intensive economic and residential development of Southern California.

The MWD Upper Feeder was instrumental to the transportation and distribution of Colorado River water to participating cities in Southern California. After Colorado River traversed the Mojave Desert from Nevada to Riverside in the Colorado River Aqueduct, the Upper Feeder pipeline was the practical means by which the participating cities accessed Colorado River water. The need for Colorado River water was dire in the 1920s, and the 2,200 square miles of coastal plain surrounding the City of Los Angeles was ripe for residential, commercial, industrial, and agricultural development. However prior to receiving Colorado River water, municipalities in the arid region relied on outdated and overtaxed irrigation systems, artesian wells and groundwater, or private water companies to furnish water, or face annexation by City of Los Angeles in order to access the Los Angeles Department of Water and Power’s Owens River water sources. Most smaller municipalities in the region simply lacked the resources to import water like Los Angeles on their own. After the Colorado River Compact enabled Arizona, California Colorado, Nevada, New Mexico, Utah and Wyoming to divert portions of Colorado River water in 1923, the Metropolitan Water District of Southern California (MWD) was established in 1928, as a result of the Metropolitan Water Act. The Metropolitan Water Act outlined how to the Colorado River Aqueduct and distribution system would be located and constructed.

Construction of both distribution system and Colorado River Aqueduct began in 1931. 150 miles of distribution system were completed in 1939 and 242 miles of Colorado River Aqueduct were completed in 1941.

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The Upper Feeder was a segment of the distribution system of the MWD Colorado River Aqueduct, and the means by which the participating cities in the greater metropolitan Los Angeles area, the Inland Empire, San Diego County, and other Southern California areas got access to Colorado River water after the completion of the Hoover Dam. The MWD Upper Feeder pipeline, as well as the rest of the distribution system and Colorado River Aqueduct, were major construction programs affording thousands of jobs to Californians during the Great Depression. After both projects were completed, the increased water supply and made it possible for Southern California to enjoy widespread economic development and to be settled so densely.

For linear resources to be found eligible under Criterion A/1, it must be a key piece of the overall system. In this case, the Monrovia No. 1 tunnel is a key portion of the Upper Feeder pipeline, facilitating its portage from the south side of the San Gabriel foothills, to the San Gabriel River canyon. Further, the Monrovia No. 1 tunnel and hatch maintain their original alignment and location, which is critical to understanding their importance and significance as a historically significant piece of water infrastructure.

The Monrovia No. 1 tunnel and hatch also maintain its original undeveloped suburban and foothill setting, and continues to function as a water conveyance system operated by the original utility: Metropolitan Water District of Southern California (MWD). While setting is less important for an underground feature, maintaining the association with MWD and its continued use as a water conveyance structure are important.

As such, the Monrovia No. 1 tunnel segment transecting the proposed project APE and the above-ground access hatch, are recommended eligible for NRHP/CRHR Criterion A/1, as a component of the larger MWD Upper Feeder pipeline for the period 1931-1941, for transportation and distribution of Colorado River water to participating municipalities in Southern California, which was an enabling force for the intensive economic and residential development of Southern California.

Criterion B/2: That are associated with the lives of persons significant in our past.

Archival research failed to identify any associations with specific significant persons.

Due to a lack of identified significant associations with important persons in history, the MWD Upper Feeder and all associated components do not appear eligible under NRHP/CRHR Criterion B/2.

The entire Upper Feeder pipeline system was designed in 1931, contract for the Monrovia No. 1 tunnel was awarded to West Construction Company in 1934, the right-of-way easement was acquired in 1935 through the Silent Ranch Estate, and the Monrovia No. 1 tunnel was completed in 1937. Water first flowed through the distribution system in 1941. No date of construction could be ascertained for this hatch; however, it is assumed that the construction date is concurrent with the Monrovia No. 1 tunnel: 1937. The MWD Upper Feeder pipeline was designed by Metropolitan Water District engineer R.B. Diemer and multiple contractors were used to complete the above and below ground sections. Monrovia No. 1 tunnel was completed by contractor West Construction Company, and the majority of other concrete pipe sections completed by contractor J.F. Shea Company Inc. Like the Colorado River Aqueduct the scale and importance of the distribution system, which totaled over 150 miles and served dozens of cities across Southern California. The Upper Item #8. Page 951
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Feeder segment between Lake Matthews and Morris Reservoir is 30+ miles long and passes through the subject property in a series of subterranean tunnels. No portion of the tunnels are visible as above ground features except for a single concrete hatch. As such, this report cannot offer comment on the type or method of construction. Adequate records of the construction of the section through the subject property are well recorded; however, construction techniques could not be confirmed as the line itself was not visible during the field visit.

Despite the Upper Feeder pipeline’s historical importance and monumental scale, nothing about the original design for the Monrovia No. 1 tunnel was particularly identifiable to a specific historical period or method of construction. Concrete pipelines and tunnel construction are ubiquitous water infrastructure components and the Monrovia No. 1 tunnel and MWD Upper Feeder pipeline as a whole do not distinguish themselves other than by its size. The Upper Feeder pipeline as a whole is associated with MWD engineer R.B. Diemer, who despite his later role as chief engineer of MWD for nine years, does not rise to the level of master engineer. The Monrovia No. 1 tunnel is utilitarian infrastructure and does not possess high artistic value. Finally, the Monrovia No. 1 tunnel and the concrete hatch are components of a significant and distinguishable work of twentieth century water engineering and a major infrastructure development project, however they are subsurface components and not visible. Therefore, they are not representative of the pipeline as a whole. Therefore, the MWD Upper Feeder subsurface tunnel segment and associated infrastructure, including the hatch, do not appear eligible under NRHP/CRHR Criterion C/3.

Criterion D/4: That have yielded, or may be likely to yield, information important in prehistory or history.

The Upper Feeder pipeline is not likely to yield information important to understanding prehistory or history. Therefore, Upper Feeder pipeline does not appear eligible under NRHP/CRHR Criterion D/4.

City of Glendora Historic Resource or Landmark Designation Criteria

1. The proposed preserved features exemplify or reflect special elements of historical, architectural, archaeological, cultural, or aesthetic heritage.

The Monrovia No. 1 tunnel and hatch, which traverse the proposed project APE, exemplifies special elements of City of Glendora’s history. The addition of this water to the city existing water system allowed for the continuation of and assurance of water for irrigated crops in Glendora, allowing the Glendora citrus industry to persist until the mid-1960s, when residential and economic development pressure overrode the citrus industry’s land requirements. Therefore, the Monrovia No. 1 tunnel and hatch are recommended eligible as a City of Glendora Historic Resource or Landmark under Criterion 1.

2. The proposed preserved features are identified with persons or events significant in local, state, or national history.

Archival research failed to identify any associations with significant persons at the local, state, or national level. Therefore, the Monrovia No. 1 tunnel and hatch are not eligible as a City of Glendora Historic Resource or Landmark under Criterion 2.

3. The proposed features embody distinctive characteristics of a style, type, period or method of construction or are valuable examples of the use of indigenous materials or craftsmanship.

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The Monrovia No. 1 tunnel and hatch are not particularly outstanding or innovative examples of 1930s-era monumental-scale water infrastructure. All components of the Upper Feeder tunnel in the APE are underground and Dudek was not able to verify the condition, construction, or alterations to the pipeline. Therefore, the Monrovia No. 1 tunnel and hatch are not eligible as a City of Glendora Historic Resource or Landmark under Criterion 3.

4. The proposed preserved features are representative of the notable work of a builder, designer or architect.

Archival research identified that the MWD Upper Feeder’s engineer is associated with MWD engineer R.B. Diemer, who despite his later role as chief engineer of MWD for nine years, does not rise to the level of master engineer. Therefore, the Monrovia No. 1 tunnel and hatch are not eligible as a City of Glendora Historic Resource or Landmark under Criterion

4. Integrity Discussion
The Monrovia No. 1 tunnel and hatch, a segment of the Upper Feeder pipeline that traverses the proposed project APE, is underground and was not visible during survey. Therefore, Dudek may not comment on the condition, state of materials, or alterations to the pipeline. Dudek recommends that the pipeline does retain integrity of location as it maintains its original 1930s alignment. The Monrovia No. 1 tunnel segment also retains integrity of its above ground setting as the underground pipeline traverses an underdeveloped portion of the proposed project APE in the southeast to a more remote, completely undeveloped portion of the proposed project APE in the north. However because the pipeline is a subterranean feature, integrity of the aboveground setting is not necessary for the pipeline to convey its significance. Due to the lack of accessibility of the pipeline Dudek may not comment on the integrity of design, materials, workmanship, or feeling of the pipeline as these could not be verified without visual access to the segment. Archival research indicates there have been no changes to the pipeline in the proposed project APE’s use, design, alignment, or materials since it was constructed.

The pipeline retains integrity of association with the MWD as the pipeline retains its original ownership and function.

B12. References (continued):

Argus. 1935. “Citrus Area Confers with Metropolitan.” Newspapers.com: Covina Argus.

July 26, 1935, pg. 1.

Creason, Glen. 2015. “CityDig: This 1938 Map Details Every Dramatic Stretch of the 242-Mile-Long Colorado River Aqueduct.” Los Angeles Magazine. Published February 11, 2015, accessed August 8, 2019. https://www.lamag.com/citythinkblog/citydig1938-map-details-every-dramatic-stretch-242-mile-long-colorado-river-aqueduct/ Desert Sun. 1938. “Construction of Colorado River Aqueduct Nears Completion.” California Digital Newspaper Collection: Desert Sun Volume XI, No 51, July 22, 1938.

Hager, William H. 2015. Hydraulicians in the USA 1800-2000: A biographical dictionary of leaders in hydraulic engineering and fluid mechanics. London: CRC Press.

Accessed August 19, 2019.
https://books.google.com/books?id=EAVCCwAAQBAJ&pg=PA1969&lpg=PA1969&dq=R.B.+Diem er+engineer&source=bl&ots=HMpd2IyYxD&sig=ACfU3U11zHLrOcvKwe37Bw3erwoOULRc2w&hl=e Item #8. Page 953
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n&sa=X&ved=2ahUKEwjDrL7F1I_kAhVjhq0KHXuxBXQQ6AEwEHoECAgQAQ#v=onepage&q=R.B.%20Di emer%20engineer&f=false
Hinds, Julian. 1935. Letter to Honorable Board of Directors of the Metropolitan Water District of Southern California. RE: “Upper Feeder Line Right of Way and Waiver – Silent Estate.” December 6, 1935. Accessed August 8, 2019. http://mwdh2o.com/WhoWeAre/Board/Board-Meeting/Board%20Archives/1935/12- Dec/Letter/064739488.pdf#search=silent%20ranch
LAT (Los Angeles Times). 1934. “Great Aqueduct Moves Forward at Brisk Pace.” Newspapers.com: The Los Angeles Times. August 19, 1934, pg. 16.

LAT. 1936. “Giant Pipe Being Placed for Aqueduct Project.” Newspapers.com: The Los Angeles Times. March 26, 1936, pg. 28.

SBCS (San Bernardino County Sun). 1936a. “Work Begun on Aqueduct Project Through Valley.” Newspapers.com: San Bernardino County Sun (San Bernardino, California).

March 27, 1936, pg. 12.

SBCS. 1936b. “New Districts May Share Water of Colorado River.” Newspapers.com: San Bernardino County Sun. August 11, 1936, pg. 19.

WDPJ (Wilmington Daily Press Journal.) 1936. “Metropolitan Aqueduct Has World’s Biggest Pipeline.” Newspapers.com: Wilmington Daily Press Journal (Wilmington, California). June 4, 1946, pg. 3.

Weymouth, F.E. 1939. History and First Annual Report for the period ending June 30, 1938.

Los Angeles: Metropolitan Water District of Southern California. http://www.mwdh2o.com/PDF_Who_We_Are/1.5.1_Inaugural_Annual_Report_1939.pdf Item #8. Page 954
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P1. Other Identifier: Silent Ranch; Glendora Girl Scout Camp DPR 523A (9/2013) *Required information
State of California  The Resources Agency Primary #
DEPARTMENT OF PARKS AND RECREATION HRI #
PRIMARY RECORD Trinomial
NRHP Status Code 6Z
Other Listings
Review Code Reviewer Date
*P2. Location:  Not for Publication  Unrestricted
*a. County Los Angeles and (P2c, P2e, and P2b or P2d. Attach a Location Map as necessary.) *b. USGS 7.5' Quad Glendora Date 1995 T 1N; R 10W; SE ¼ of SE ¼ of Sec 24; San Bernardino B.M. c. Address 950 Silent Ranch Drive City Glendora Zip 91741 d. UTM: (Give more than one for large and/or linear resources) Zone 11S , 419223 mE/ 3779467 mN e. Other Locational Data: (e.g., parcel #, directions to resource, elevation, decimal degrees, etc., as appropriate) APN: 8684-045-004; 950 North Silent Ranch Drive, at the northern terminus of Grand Avenue in the City of Glendora, is approximately 27 acres in size. Access is provided through a gated entrance on W Palm Drive. Elevation: 1030-1143 feet asml; Lat/Long: 34.151953, - 117.875441
*P3a. Description: (Describe resource and its major elements. Include design, materials, condition, alterations, size, setting, and boundaries) Rancho Los Alisos/Silent Ranch and Camp Aventura occupy the same address and parcel, and are part of the same chain of ownership. Rancho Los Alisos was purchased in 1907 and developed beginning in 1908. The original house for Rancho Los Alisos was demolished between 1964 and 1968. The modern house of the property was built in 1980 and therefore not eligible for evaluation. Components of the Rancho (See Continuation Sheet) *P3b. Resource Attributes: (List attributes and codes) HP29 – Landscape Architecture; (See BSO Sheet, B11) *P4. Resources Present:  Building  Structure  Object  Site  District  Element of District  Other (Isolates, etc.) P5b. Description of Photo: (view, date,
accession #) View of open
basin, looking east (IMG
2235)
*P6. Date Constructed/Age and
Source:  Historic  Prehistoric
 Both 1907-1953; 1953-1974
*P7. Owner and Address:
(private owner)
950 Silent Ranch Drive
Glendora, CA 91741
*P8. Recorded by: (Name, affiliation,
and address) Kate Kaiser, MSHP
DUDEK, 38 N Marengo Ave
Pasadena, CA 91101
*P9. Date Recorded: 8/1/2019
*P10. Survey Type: (Describe)
pedestrian
*P11. Report Citation: Dudek.
2019. Historical Resources
Technical Report for
Silent Ranch Hillside
Subdivision Project. Prepared for City of Glendora Planning Department. *Attachments: NONE Location Map Continuation Sheet Building, Structure, and Object Record Archaeological Record District Record Linear Feature Record Milling Station Record Rock Art Record Artifact Record Photograph Record  Other (List):

P5a. Photograph or Drawing (Photograph required for buildings, structures, and objects.) Item #8. Page 955
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*Map Name: Glendora, Calif. *Scale: 1:24,000 *Date of map: __1995___________ DPR 523J (Rev. 1/1995)(Word 9/2013) *Required information State of California  Natural Resources Agency Primary # DEPARTMENT OF PARKS AND RECREATION HRI#
LOCATION MAP Trinomial
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Item #8. Page 957
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*Resource Name or # (Assigned by recorder) Rancho Los Alisos/Camp Aventura *NRHP Status Code 6Z

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DPR 523B (9/2013) *Required information
State of California  The Resources Agency Primary #
DEPARTMENT OF PARKS AND RECREATION HRI#

BUILDING, STRUCTURE, AND OBJECT RECORD
B1. Historic Name: Rancho Los Alisos/Silent Ranch (1907-1953); Camp Aventura (1953-1974) B2. Common Name: Silent Ranch Estates (1974-present)
B3. Original Use: single-family residence; orchards B4. Present Use: single-family residence *B5. Architectural Style: Rancho Los Alisos: n/a; Camp Aventura: Mid-Century Modern *B6. Construction History: (Construction date, alterations, and date of alterations) (See Continuation Sheet)
*B7. Moved? No Yes Unknown Date: Original Location:
*B8. Related Features: Monrovia Runnel No. 1. (MWD Upper Feeder segment); USFS/LACFCD Crib dams
B9a. Architect: n/a b. Builder: n/a
*B10. Significance: Theme Area
Period of Significance Property Type Applicable Criteria (Discuss importance in terms of historical or architectural context as defined by theme, period, and geographic scope. Also address integrity.)
(See Continuation Sheet)
B11. Additional Resource Attributes: (List attributes and codes) HP38. Women’s property; HP31. Urban Open Space; HP4. Ancillary Building; AH2. Foundations; AH6. Water Conveyance System; AH11.

Walls, fences
*B12. References:
(See Continuation Sheet)
B13. Remarks:
*B14. Evaluator: Kate Kaiser, MSHP
architectural historian
*Date of Evaluation: 8/26/2019
(Sketch Map with north arrow required.)
(This space reserved for official comments.)
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P3a Description (continued): Los Alisos grounds, such as the rock-lined structures, constructed rock water features and Black Bass Pool were constructed between 1908 and 1910 and are associated with the original period of development. Camp Aventura was purchased in 1953 and developed between 1953 and 1958. The camp was abandoned in 1971 and most camp buildings were demolished when it was sold in 1974.

The width of the bench appears to be 3’6”-4’ with flared sides (Figure 1 and 2).

Figure 1. Left: Rock wall and bench feature (IMG_4041); Right: 1910 photo of rock lined road and bench (Glendora Historical Society)
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Figure 2. Another segment of rock-line road (IMG 4003)
Rancho Los Alisos: Black Bass Pool
This pool feature is located northwest of 950 Silent ranch Drive house, long a ridgeline, immediately north of a mature lemon grove. The pool feature is visible in photographs dating to 1910, was featured in a newspaper article from 1911 describing its function, and was developed between 1908 and 1910. The pool feature extends at least ten feet below the rim. The pool rim rises roughly 1’6” above ground level. The pool is circular and has an approximate diameter of 25 feet. In the center of the pool is a burned metal and wood post, capped with a metal hood. The pool is constructed of concrete reinforced with metal mesh, the face of which is badly spalling in some places. Around the rim of the pool is a wood ring, which still contains metal fixtures for the gate feature which has been lost. A metal ladder provides access to the pool interior (Figure 3 and 4). The entire feature has been burned and the pool is partially filled with burned debris.

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Figure 3. Left: concrete pool, looking southeast (IMG_4054); Right: 1910 photo of bass pool (Glendora Historical Society)
Figure 4. Profile view of pool feature wall (IMG 1350)
Rancho Los Alisos: Constructed Rock “cave”, wall, steps, and water pool features The constructed rock cave feature, wall, steps, and pools are located immediately northwest of the black bass pool on the ridge above (northwest of) the house. The constructed rock cave is constructed concrete faced with semi-coursed, locally sourced, dark grayish red stone. Over the arch of the entrance to the “cave” the rocks are arranged in an arch, with a keystone, and two 2-3 foot tall rock walls slope away from it (Figure 5). The opening itself is roughly 2 feet wide by 3 feet tall. Downhill of and connected to the cave by a continuous low rock-faced wall are at least two circular shallow rockItem #8. Page 961 Meeting Date: 1/24/2023 / Packet Page #: 1026
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lined concrete pools, which produce a cascade effect downhill towards the black bass pool. Uphill of the cave is a 4-foot high rock faced concrete retaining wall. A set of 10 narrow stairs lead to the uphill area above the wall, and are also constructed of concrete and local dark gray-red stone (Figure 6).

Figure 5. Entrance to rock “cave” showing rock walls sloping away, view to west (IMG_4051)
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Figure 6. Stairs and retaining wall immediately right (northwest) of cave (IMG_1377) Rancho Los Alisos: Constructed Rock Fountain
The constructed rock fountain feature and pools is located northwest of the black bass pool on the ridge above (northwest of) the house, and southeast of the constructed rock cave. The constructed rock fountain is constructed concrete faced with semi-coursed, locally sourced, dark grayish-red stone (Figure 7). There is a smoothed, concrete, tool formed basin below the upper pour spout, forming the drinking fountain, which is roughly 2 feet x 1’6” in diameter and oval shaped. The fountain basin portion is roughly 3 feet above current ground surface and is obscured by brush.

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Figure 7. Left: view of steps looking northeast (IMG_1357); Right: 1910 postcard of fountain pavilion. (Glendora Historical Society)
Rancho Los Alisos: Stone Stairs to Dining Pavilion
Stone stair feature is located due north of the 950 Silent Ranch Drive house. The stair feature is visible in photographs dating to 1910, and was developed between 1908 and 1910. The feature consists of a set of windowing, narrow concrete construction, stonefaced steps, approximately 8 inches high, 8 inches tread, and roughly 2 feet wide, with a rock and concrete border to each side. The stair is banked into a steep hillside just north of the house and extends downhill roughly 15 feet below the driveway north of the house. (Figure 8 and 9).

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Figure 8. Left: view of steps looking northeast (IMG_2394); Right: 1910 postcard of steps leading to earthen pavilion. (Glendora Historical Society) Figure 9. View of steps looking south (IMG 4006)
Camp Aventura: Restroom Building
Restroom building is a one-story, Mid-Century Modern-styled building constructed in circa 1955-1956, located northeast and immediately downhill from the 950 N. Silent Ranch Drive property and driveway (Figure 10). The building is one-story and a simple rectangle in plan, with the east portion enclosed for a three-stall restroom and privacy screen, and the west portion an open-air wash area. The building rests on a concrete slab foundation.

It features a flat roof with wide overhang and wide, angled fascia board with open eaves, Item #8. Page 965
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and is supported by wood posts and the restroom stall enclosed space. The roof is clad with rolled composition roofing and flashed with aluminum-finish metal around the edges.

The wall construction of the restroom stalls is wood stud clad with both board-and batten on the south and east elevation, and plywood on the west elevation. Along the north elevation there was a board and batten privacy wall in front of the stall doors, however, doors and privacy wall have been removed. Fixtures are still present at this building including an enameled double sink and three metal pit toilet fixtures. Along the rear (south) elevation, against the hillside, 2”x4” boards are nailed to the building exterior and support posts to provide pipe and wood board storage.

Figure 10. Main and west elevations of restroom building, view to southeast (IMG_4010)
Identified Alterations
Dudek attained all available permits pertaining to the subject property through the City of Glendora Building Department’s eTRAKit online permitting system on August 14, 2019.

The permits date from 1975 through present, which are summarized below:
 1947: Permit for house and attached garage at 575 W. Palm Drive  1950: Permit for adding Bathroom to main house at 19153 E Sierra Madre; issued to Rancho Los Alisos
 1953: Plumbing permit for adding bathroom; sewer connection and septic tank to 19153 E Sierra Madre/935 N. Silent Ranch Drive; issued to Girl Scouts  1954: Permit for new roof cover for 13’ x 26’ reservoir; issued to Girl Scouts Item #8. Page 966
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 1955: Permit for building alterations 19153 E Sierra Madre/935 N. Silent Ranch Drive; issued to Girl Scouts
 1955: Plumbing permit for 3 toilets, 2 showers, 3 lavatory wash basins, 3 kitchen sinks and 2 gas outlets to 19153 E Sierra Madre/935 N. Silent Ranch Drive; issued to Girl Scout Camp (likely for fixtures in restroom building)  1955: Building Permit for “Unit Toilet Shelter” Building, Architect Paul R. Hunter, Contractor J. Lonnie Crumpler to 19153 E Sierra Madre/935 N. Silent Ranch Drive; issued to Girl Scout Camp (possibly the restroom building)  1955: Building Permit for “Public Sanitary Unit” 8’ x 12’ Building, Architect Paul R. Hunter, Contractor J. Lonnie Crumpler to 19153 E Sierra Madre/935 N. Silent Ranch Drive; issued to Girl Scout Camp
 1955: Building Permit for “Unit Wash Shelter” Building, Architect Paul R. Hunter, Contractor J. Lonnie Crumpler to 19153 E Sierra Madre/935 N. Silent Ranch Drive; issued to Girl Scout Camp
 1955: Permit for new roof to 40’ reservoir; issued to Girl Scout Camp  1955: Permit for new roof to 80’ reservoir; issued to Girl Scout Camp Glendora  1955: Permit for Dormitory and Kitchen Building; Architect Paul R. Hunter, Contractor J. Lonnie Crumpler to 19153 E Sierra Madre/935 N. Silent Ranch Drive; issued to L.A. Girl Scouts
 1956: Permit for “Unit Wash Shelter” Building, Architect Paul R. Hunter, Contractor J. Lonnie Crumpler to 19153 E Sierra Madre/935 N. Silent Ranch Drive; issued to L.A. Girl Scouts
 1956: Permit for “Unit Toilet Shelter” Building, Architect Paul R. Hunter, Contractor J. Lonnie Crumpler to 19153 E Sierra Madre/935 N. Silent Ranch Drive; issued to L.A. Girl Scouts (possibly the restroom building)  1959: Permit for 20‘ x 30’ “Shelter – Orange Camp”; Architect Tryon & Foy, Contractor Wendell Turner to 7755 N Grand Avenue; issued to L.A. Council Girl Scouts
 1959: Permit for 20‘ x 30’ “Shelter – Lemon Camp”; Architect Tryon & Foy, Contractor Wendell Turner to 7755 N Grand Avenue; issued to L.A. Council Girl Scouts  1959: Permit for 20‘ x 30’ “Shelter – Lime Camp”; Architect Tryon & Foy, Contractor Wendell Turner for 7755 N Grand Avenue; issued to L.A. Council Girl Scouts Item #8. Page 967
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 1959: Permit for 20‘ x 42’4” “Handicraft House”; Architect Tryon & Foy, Contractor Wendell Turner for 7755 N Grand Avenue; issued to L.A. Council Girl Scouts  1959: Permit for 18’6”‘ x 42’4” “Latrine”; Architect Tryon & Foy, Contractor Wendell Turner for 7755 N Grand Avenue; issued to L.A. Council Girl Scouts  1959: Permit for 20‘ x 48’4” “Bath House” with 4 sinks, 2 showers, 10 toilet stalls, water heater and gas hookup; Architect Tryon & Foy, Contractor Wendell Turner for7755 N Grand Avenue; issued to L.A. Council Girl Scouts  1959: Permit for Public Swim Pool, Standard Plan #16472; Architect W. Taggert, Contractor Paddock Pools, for 7755 N Grand Avenue; issued to Girl Scouts of USA  1963: Permit for 1 story, single-family 1142 s.f. “Caretakers House”; Architect Tryon & Foy, Contractor Colletta and Edgely for 7755 N Grand Avenue; issued to Girl Scouts of USA
 1963: Permit for 1 story, 3000s.f. “Dining Hall and Kitchen”; Architect Tryon & Foy, for 7755 N Grand Avenue; issued to Girl Scouts of USA  1973: Permit to demolish 5 “camping structures”; contractor U.S. Navy Seabees, for 905 N. Grand Street, Glendora; issued to Angeles Girl Scout Council  1974: Permit to demolish “2 buildings, one bathhouse and misc. structures”; issued to George Deukmejian
 1975: Permit for new 6200 sf house at 950 N Silent Ranch Drive; Architect: David Hyen Associates; issued to George Deukmejian
 1980: Demolish pump house at 553 W Palm Drive; issued to George Deukmejian  1980: Grading at 950 N Silent Ranch Drive, 553 W Palm Drive, contractor G. Bart Striker; issued to George Deukmejian
 1999: New 4-car garage at 950 N Silent Ranch Drive, issued to Pam and Time Morales  1999: Permit to demolish “old Girl Scout House, approx. 600 s.f.” at 935/950 N.

Silent Ranch Drive; issued to Deukmejian Enterprises.

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B6. Construction History (continued): Rancho Los Alisos (1907-1953) Judge Charles Silent was a lawyer, judge, and a prominent real estate speculator in Los Angeles. Silent moved to Los Angeles in 1885, and made connections while representing wealthy landowners and speculators during the real estate boom of the 1880s. Silent also made key real estate investments and bought large tracts of land along the coast southwest of Los Angeles, developing the communities of Inglewood and Redondo Beach. Silent lived near the present-day University of Southern California campus, and in 1900, he created the gated subdivision of Chester Place around his home. In 1907, Judge Charles Silent purchased 110 acres just north of the town of Glendora from one of his clients, P. Shorey, though he remained in Los Angeles for a few years after the purchase. Silent continued to be engaged in both Los Angeles and Glendora, proving an influential voice in the construction of a scenic highway from Redlands to the sea, now Foothill Boulevard. (LAT 1907a, 1907b; Price 2008).

Silent became involved with the California Avocado Association and eventually became a director of the organization, growing lemons and varieties of avocados at Rancho Los Alisos. Silent engaged the local pomological societies and opened his property to the public on Sundays so that residents of Glendora could enjoy his gardens and grounds.

During this period, Silent’s property consists of a grouping of rancho-style buildings with the appearance of palm-leaved thatched roofing, and also developed rock-lined bricks paths, elaborate flower and palm tree plantings, viewing platforms, fountains, and a fishing basin where Silent stocked black bass (Figures 11, 12). According to a newspaper feature about the property, Silent irrigated his vast property using spring water from further up the mountain. Silent supposedly tunneled north to the springs, and brought water through a series of underground reservoirs, and pipelines to his property. Once there, Silent irrigated his plants but also created “aa series of reservoirs that are connected here and there with artistic stone grottos and scenes of flowing and falling streams” (Argus 1910: 2). After Silent’s death in 1918, and his wife’s death in 1921, the property remained unused, and cared for by a small caretaker staff. The Silent estate eventually sold portions of the ranch to real estate developers. Though the original house was demolished between 1964 and 1968, and a new residence constructed on the location, some of these plantings, water conveyance systems, and rock-lined landscape features remain (Argus 1910, 1921; LAT 1918; Price 2008; UCSB 2019).

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Figure 11. Postcard of Rancho Los Alisos ranch house building group. (Silent Ranch subject files, Glendora Historical Society)
Figure 12. View to main buildings of Rancho Los Alisos, looking southwest, c 1910 (Oversized photos, Glendora Historical Society)
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Camp Aventura (1953-1974)
In 1953, the Los Angeles Council of Girl Scouts and Girl Scouts of America began making formal inquiries about purchasing 295 acres for a camp in Glendora, on the former Silent Ranch Property. Beginning as early as 1953, a Master Plan was in the works for the camp, which planned to develop 12 unit sites on the property. The Los Angeles Council of Girl Scouts member troops raised the funds for the camp through yearly cookie drives and other fund raising efforts, and eventually purchased 295 acres of the former Silent Ranch estate.

In October 1955, Camp Aventura was officially dedicated and opened. By 1956, four buildings and 12 tent pads were present at the site. The area had been cleared of orchard trees and in 1956, Girl Scouts planted trees and other vegetation around the new camp. In 1959, the Los Angeles Council of Girl Scouts made its final payment on Camp Aventura in Glendora, owning the property outright. The camp continued to operate until at least 1971, and in 1974, the Los Angeles Council of Girl Scouts sold the Camp property to George and Jean Deukmejian . The Deukmejians demolished the remaining Girl Scout buildings on the property, but donated a 30-acre parcel to the City of Glendora to use as dedicated open space (LAT 1953, 1956, 1958, 1959; Leagle 2019; Valley News 1956; UCSB 2019). According to legal documentation:

Silent Ranch Estates Residential Subdivision (1974-present) George Deukmeijian first applies for a demolition permit for the Girl Scout Camp in 1974.

Deukmejian began building a new residence at the site of the former Rancho Los Alisos house in 1976 and it was completed by 1980. By 1981, the property also had a pool house, pool, and landscaped lawns, and small immature orchard northwest of the building. In 1982, Deukmejian’s company, Deukmejian Enterprises, began redeveloping the surrounding property into a residential subdivision called Silent Ranch Estates with 15 lots. Lots were prepared and custom-built homes offered beginning in 1984, and later the same year, City of Glendora allowed it to become a private, gated community. By 2003, all 15 lots were filled (LAT 1984a, 1984b, 1985; UCSB 2019).

Associated People: Judge Charles Silent (1842-1918)
Charles K. Silent was born in 1842 in Prussia, but emigrated in 1848 to Columbus Ohio with his family due to the Revolutions of 1848. In 1856, at 14 Silent left home for New York and then onto a ship for San Francisco. Silent earned a teacher’s certificate by age 17 and worked as a teacher for several years before enrolling in University of the Pacific in 1862. He married Emma Daniel in 1864 and had three children before her death in 1870.

Silent passed the California bar exam in 1868 and became partner to San Jose law firm of Moore, Laine & Silent. He remarried Mary Tantau in 1874 and developed connections in law and to the railroad industry. In 1878, President Rutherford B. Hayes appointed Silent as an associate justice of the Supreme Court of Arizona, however, Silent continued financial interests in railroads in mining during his tenure and in 1880 was investigated by the U.S. Attorney general for his conflict of interest, and soon after the investigation, resigned from the court and returned to practicing law. Silent grew wealthy from his law practice in Tuscon but due to declining health, relocated to Los Angeles California in 1885 (LAT 1918; SFE 1878; Spitzzeri 2019).

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In California, Silent joined W.P. Wade and W.F Fitzgerald in a law practice and continued serving wealthy clients in the metropolitan area, while simultaneously investing in the booming Southern California real estate. Silent joined many other wealthy Los Angeles elite in forming real estate companies such as Centinela-Inglewood Land Company (1887), and creating coastal towns such as Redondo Beach and Inglewood, and investing heavily in Azusa, Redlands, and the Foothill Boulevard road. Later he formed the firm Houghton, Silent, and Campbell with men he met through Wade and Fitzgerald’s connections. Silent moved into Nathan Vail’s mansion and formed the gated subdivision called Chester Place in 1899, creating a private park just southwest of the metropolitan center. Silent also practiced horticulture as a hobby, and perhaps as a result of this hobby and his multitude of connections to wealthy Los Angeles personalities and government officials, he was appointed to the head of the Los Angeles Parks Commission. There he worked on remodeling Pershing Square and Elysian Park, and secured Griffith Park from Colonel Griffith J.

Griffith (LAT 1918; Spitzzeri 2019).

B10. Significance (continued): NRHP/CRHR Statement of Significance Criterion A/1: That are associated with events that have made a significant contribution to the broad patterns of our history.

Camp Aventura was one of nearly 40 Girl Scouts of America organizations camps established in Southern California between 1930 and 1970. Only one remaining feature of the original camp, established in 1953 remains: a 3-stall restroom and washroom building. The other buildings were demolished by the Navy Seabees and George Deukmeijian between 1973 and 1974. As with Rancho Los Alisos, the camp may have made an impression on its occasional users, but did not particularly influence the growth of Glendora, or host any significant historical events. Despite local popularity as a public park and later as a Girl Scout campground, no significant historical associations were found in the course of research.

Due to a lack of identified significant associations with events important to history, the subject property does not appear eligible under NRHP/CRHR Criterion A/1.

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Criterion B/2: That are associated with the lives of persons significant in our past.

Archival research identified a single important person, Judge Charles K. Silent (1842- 1918), associated with the rancho Los Alisos/ Camp Avenura property. Silent was an influential lawyer, real estate investor, and former judge at a formative period in the history of Los Angeles. He was instrumental in the formation of Redondo Beach and Inglewood via his company the Centinela-Inglewood Land Company (1887). Silent also created the first gated community In Los Angeles (Chester Place), and was influential in his role as City of Los Angeles Parks Commissioner. Despite this association, Silent’s relationship with rancho Los Alisos/Camp Aventura is after the influential period of his life, after he had retired from his law practice and stopped working as Parks Commissioner. Rancho Los Alisos was not associated with the period of historical influence in Silent’s life; therefore the subject property does not appear eligible under NRHP/CRHR Criterion B/2.

While interesting in construction, the majority of rock structures, original landscaping, and the original buildings on the property have been lost and the remaining structures lack the integrity to convey significance under this criteria. They cannot be positively identified as the work of a master, as the Greene & Greene house plans from 1907 do not include landscaping or structures aside from the main house. The structure have deteriorated and no longer possess high artistic value, and are not part of a district or entity whose components lack individual distinction.

The later Camp Aventura building has a similar issue. The only remaining building of the original 12 buildings and camp grounds is one Mid-Century Modern-style restroom building, badly deteriorated since its abandonment in the 1970s. Constructed in 1955-1956, the restroom building retains few character defining features of the style including thin, upright supports and a flat roof with angled fascia board detailing. The original architect was narrowed down to either Paul R. Hunter or Tryon & Foy, neither of which can be considered master architects. The building has no artistic value and while it was originally a component of a larger Girl Scout-related campground, it is the only remaining features and as such does not adequately convey this distinctive association. Therefore, the subject property does not appear eligible under NRHP/CRHR Criterion C/3.

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Criterion D/4: That have yielded, or may be likely to yield, information important in prehistory or history.

The subject property is not likely to yield information important to understanding prehistory or history. Therefore, the subject property does not appear eligible under NRHP/CRHR Criterion D/4.

City of Glendora Historic Resource or Landmark Designation Criteria

1. The proposed preserved features exemplify or reflect special elements of historical, architectural, archaeological, cultural, or aesthetic heritage.

2. The proposed preserved features are identified with persons or events significant in local, state, or national history.

3. The proposed features embody distinctive characteristics of a style, type, period or method of construction or are valuable examples of the use of indigenous materials or craftsmanship.

4. The proposed preserved features are representative of the notable work of a builder, designer or architect.

Archival research failed to resolve whether the Rancho Los Alisos stone structures were designed by architects Greene & Greene as landscaping plans for the property have not been retained. Archival research also failed to identify if the Camp Aventura restroom is associated with architect Paul R. Hunter or Tryon & Foy, nor is the building definitively visibly the work of either architect. In both cases, the remaining Rancho Los Alisos/Camp Aventura structures and buildings are not representative of the notable work of a builder, designer, or architect. Therefore, Rancho Los Alisos/Camp Aventura are not eligible as a City of Glendora Historic Resource or Landmark under Criterion 4.

Item #8. Page 974
Meeting Date: 1/24/2023 / Packet Page #: 1039
DPR 523L (Rev. 1/1995)(Word 9/2013) *Required information State of California  Natural Resources Agency Primary# DEPARTMENT OF PARKS AND RECREATION HRI #
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CONTINUATION SHEET
Property Name: __ Rancho Los Alisos/Camp Aventura _____________________________ Page __20__ of __21__
Integrity Discussion
The Rancho Los Alisos/Camp Aventura buildings and structures retain only integrity of location, as they remain in their original locations. These features do not retain integrity of setting as the setting of both Rancho Los Alisos and Camp Aventura have been lost in subsequent fires, residential subdivision development, and flood control structure development. No discernable portions of the Rancho Los Alisos or Camp Aventura settings are intact. These features also do not retain integrity of design, materials or workmanship as all stone and concrete structures are in advanced states of decay, sometimes with the entire stone facing section missing. The Camp Aventura building has had several material portions removed so discerning original design intent, materials or workmanship was not possible. All features do not retain integrity of feeling as they do not convey the feeling of a mid-century Girl Scout camp with both accessible and remote camp sites nor convey the feeling of an early twentieth century several hundred-acre estate and intermittent park. Finally, no features retain integrity of association as all association with the Silent Estate and with the Los Angeles Girl Scout Council has been lost by the encroaching residential subdivision development.

B12. References (continued):

Argus (Covina Argus). 1910. “Above the Haze-Clouds on Sun-Flooded Los Alisos.” Newspapers.com: Covina Argus (Covina, California). May 28, 1910, pg. 2.

Argus. 1921. “The Silent Homestead.” Newspapers.com: Covina Argus. July 15, 1921, pg.

8. Greene & Greene, Architects. 1908. “Ranch houses for Judge Chas. Silent at Glendora, Cal.” 14 drawings various media 88.7 x 90.9 cm. (35 x 35 7/8 in.) or smaller.

Greene & Greene Architectural Records & Paper Collections, Avery Architectural & Fine Arts Library. Accessed August 15, 2019.
http://www.columbia.edu/cu/lweb/eresources/archives/avery/greene/html/subs/NYDA8 9-F763.html
LAT (Los Angeles Times). 1907a. “Large Tract Purchased: Judge Silent of Glendora Buys Land near Foothill Town.” Newspapers.com: The Los Angeles Times. May 19, 1907, pg. 72.

LAT. 1907b. “Lofty Bridge for Highway: Novelty Urged in Route of Foothill Boulevard.” Newspapers.com: The Los Angeles Times. December 19, 1907, pg. 23.

LAT. 1918. “Charles Silent Taken By Death.” Newspapers.com: The Los Angeles Times.

December 15, 1918, pg. 9.

LAT. 1953. “Experts OK Girl Scout Camp Site.” Newspapers.com: The Los Angeles Times.

July 24, 1953, pg. 51.

LAT. 1956. “Girls’ Camps Nestle Among Rare Flora on Ranch Made Into Garden.” Newspapers.com: The Los Angeles Times. September 2, 1956, pg. 107.

LAT. 1958. “Fashions to Aid Girl Scout Camp.” Newspapers.com: The Los Angeles Times.

August 15, 1958, pg. 31.

Item #8. Page 975
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Property Name: __ Rancho Los Alisos/Camp Aventura _____________________________ Page __21__ of __21__
LAT. 1959. “Girl Scouts Complete Payments on Camp.” Newspapers.com: The Los Angeles Times. February 12, 1959, pg. 56.

LAT. 1984a. Advertisement. “Silent Ranch Estates.” Newspapers.com: The Los Angeles Times. March 31, 1984, pg. 293.

LAT. 1984b. “San Gabriel Valley Digest Glendora.” Newspapers.com: The Los Angeles Times. May 10, 1984, pg. 308
LAT. 1985. Advertisement. “At Home.” Newspapers.com: The Los Angeles Times. June 1, 1985, pg. 25.

Leagle. 2019. “41 T.C.M. 738 (1981). T.C. Memo. 1981-24. George Deukmejian and Jean Deukmejian v. Commissioner. United States Tax Court. Filed January 26, 1981.

Accessed August 8, 2019. https://www.leagle.com/decision/198177941gdtcm7381594 Price, R.L. 2008. Glendora (Postcard History Series). Arcadia Publishing. Charleston, South Carolina.

UCSB (University of California, Santa Barbra). 2019. Historic Aerial Photographs of Silent Ranch property, Glendora, CA dating from 1927, 1933, 1934, 1938, 1953, 1956, 1960, 1968, and 1976. Map & Imagery Laboratory (MIL) UCSB Library, Accessed August 6, 2019. http://mil.library.ucsb.edu/ap_indexes/FrameFinder.

Valley News. 1956. “Girl Scouts Plant Seedlings at Campsite Near Glendora” Newspapers.com: Valley News (Van Nuys, California). January 12, 1956, pg. 55.

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P1. Other Identifier:

DPR 523A (9/2013) *Required information
State of California  The Resources Agency Primary #
DEPARTMENT OF PARKS AND RECREATION HRI #
PRIMARY RECORD Trinomial
NRHP Status Code 6Z
Other Listings
Review Code Reviewer Date
*P2. Location:  Not for Publication  Unrestricted
*a. *a. County Los Angeles and (P2c, P2e, and P2b or P2d. Attach a Location Map as necessary.) *b. USGS 7.5' Quad Glendora Date 1995 T 1N; R 10W; SE ¼ of SE ¼ of Sec 24; San Bernardino B.M. c. Address 950 Silent Ranch Drive City Glendora Zip 91741 d. UTM: (Give more than one for large and/or linear resources) Zone 11S , 419277 mE/ 3779446 mN Zone 11S , 419366 mE/ 3779454 mN; Zone 11S , 419531 mE/ 3779488 mN e. Other Locational Data: (e.g., parcel #, directions to resource, elevation, decimal degrees, etc., as appropriate) These dams and channel are located in three minor riparian drainages on a 27-acre parcel at 950 North Silent Ranch Drive (APN: 8684-045-004), at the northern terminus of Grand Avenue in the City of Glendora. Elevation: 1099 feet amsl *P3a. Description: (Describe resource and its major elements. Include design, materials, condition, alterations, size, setting, and boundaries) In three of the small riparian canyons in the proposed project APE, there are crib dams and one flood control channel. In 1970 the US Forest Service, City of Glendora, Los Angeles County Flood Control District, and Army Corps of Engineers, responded to a 1968 fire and 1969 mudslide in the City of Glendora by installing these crib dams to abate future flood and mudslide damages. (See Continuation Sheet)
*P3b. Resource Attributes: (List attributes and codes) HP21 – dam; AH6 – water conveyance system *P4. Resources Present:  Building  Structure  Object  Site  District  Element of District  Other (Isolates, etc.) P5b. Description of Photo: (view, date,
accession #) East Crib Dam and
channel, looking north
(IMG_4024)
*P6. Date Constructed/Age and
Source:  Historic  Prehistoric
 Both 1970; LAT 1970
*P7. Owner and Address:

Joint: US Forest Service
(Angeles National Forest), Los
Angeles County Flood Control
District and City of Glendora
*P8. Recorded by: (Name, affiliation,
and address Kate Kaiser, MSHP
DUDEK, 38 N Marengo Ave
Pasadena, CA 91101
*P9. Date Recorded: 8/1/2019
*P10. Survey Type: pedestrian
*P11. Report Citation: Dudek. 2019.

Historical Resources
Technical Report for Silent Ranch Hillside Subdivision Project. Prepared for City of Glendora Planning Department.
*Attachments: NONE Location Map Continuation Sheet Building, Structure, and Object Record Archaeological Record District Record Linear Feature Record Milling Station Record Rock Art Record Artifact Record Photograph Record  Other (List):

P5a. Photograph or Drawing (Photograph required for buildings, structures, and objects.) Item #8. Page 977
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*Map Name: Glendora, Calif. *Scale: 1:24,000 *Date of map: __1995___________ DPR 523J (Rev. 1/1995)(Word 9/2013) *Required information State of California  Natural Resources Agency Primary # DEPARTMENT OF PARKS AND RECREATION HRI#
LOCATION MAP Trinomial
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Item #8. Page 979
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*Resource Name or # (Assigned by recorder) USFS/LACFCD Dams and channel *NRHP Status Code 6Z

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DPR 523B (9/2013) *Required information
State of California  The Resources Agency Primary #
DEPARTMENT OF PARKS AND RECREATION HRI#

BUILDING, STRUCTURE, AND OBJECT RECORD
B1. Historic Name: USFS/LACFCD Dams and channel
B2. Common Name: USFS/LACFCD Dams and channel
B3. Original Use: Flood and erosion control B4. Present Use Flood and erosion control *B5. Architectural Style: Crib-style dams
*B6. Construction History: (Construction date, alterations, and date of alterations) (See Continuation Sheet)
*B7. Moved? No Yes Unknown Date: Original Location:
*B8. Related Features:

Same Parcel: Rancho Los Alisos/ Camp Aventura
Same Parcel: Monrovia Runnel No. 1 (MWD Upper Feeder) segment B9a. Architect: unknown b. Builder: USFS and LACFCD
*B10. Significance: Theme n/a Area n/a
Period of Significance n/a Property Type n/a Applicable Criteria n/a (Discuss importance in terms of historical or architectural context as defined by theme, period, and geographic scope. Also address integrity.)
(See Continuation Sheet)
B11. Additional Resource Attributes: (List attributes and codes) *B12. References:
(See Continuation Sheet)
B13. Remarks:
*B14. Evaluator: Kate Kaiser, MSHP architectural historian *Date of Evaluation: 8/26/2019
(Sketch Map with north arrow required.)
(This space reserved for official comments.)
Item #8. Page 980
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Property Name: ___ USFS/LACFCD Dams and channel _____________________________________________________ Page __4__ of __10__
P3a. Description (continued):

West crib dam (1970)
The West crib dam is a concrete crib check dam, built in 1970 located in the west-most canyon of the property, northwest of the 950 Silent Ranch Drive house (Figure X). The dam was one of forty such concrete crib check dams constructed after a fire and flooding event in 1969. The dam is constructed of reinforced concrete beams laid in crib bays with no mortar and metal netting behind which rock and soil may accumulate in a debris cone while allowing water the pass through the dam. The dam portion is a squared U shape, extending 75 feet wide (11 visible crib widths) by 6 feet thick, and rises near 20 feet at its height and 15 feet in the middle. A concrete slurry mix called gunnite was applied to a central crib to form a spillway/pour-over location. The lower concrete sill below the dam rises roughly 2-3 feet above the ground surface. Between the dam and sill the hillside to the north and south are both covered with a gunnite, which was intended to prevent erosion of the hillside between the dam and sill, and erosion around the dam footings. One concrete beam on the upper right side of the dam bears the incised mark of “USFS 1970 W 12” and a metal plaque from the LACFCD. A pair of metal bars are attached to right side of the dam face, to act as ladder with the crib beams as rungs.

Figure 1. West crib dam, with dam in background, concrete sill in foreground, looking northwest (IMG_1264)
Center crib dam (1970)
The Center crib dam is a concrete crib check dam, built in 1970 located in the secondfrom-west canyon of the property, northeast of the 950 Silent Ranch Drive house (Figure X). The dam was one of forty such concrete crib check dams constructed after a fire and flooding event in 1969. The dam is constructed of reinforced concrete beams laid in crib bays with no mortar and metal netting behind which rock and soil may accumulate in a debris cone while allowing water the pass through the dam. The dam portion is a squared Item #8. Page 981
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Property Name: ___ USFS/LACFCD Dams and channel _____________________________________________________ Page __5__ of __10__
U shape, extending 15 feet wide (4 visible crib widths) by 6 feet thick, and rises approximately 12 feet at its height and 8 feet in the middle. Gunnite was applied to the central crib from ground surface to top of dam to form a spillway. No lower sill was visible, through thick vegetation growth. The hillside to the east and west of the area below the dam are covered with a gunnite, rising from visible ground surface to a few feet above the lip of the dam. One concrete beam on the upper right side of the dam bears a metal plaque from the LACFCD. A pair of metal bars are attached to right side of the dam face, to act as ladder with the crib beams as rungs.

Figure 2. Center crib dam, looking north (IMG_1332)
East crib dam and channel (1970)
The East crib dam is a concrete crib check dam, built in 1970 located in the east-most canyon of the property, northeast of the 950 Silent Ranch Drive house (Figure X). The dam was one of forty such concrete crib check dams constructed after a fire and flooding event in 1969. The dam is constructed of reinforced concrete beams laid in crib bays with metal netting behind which rock and soil may accumulate in a debris cone while allowing water the pass through the dam. The dam portion is a squared U shape, extending approximately 85 feet wide (14 visible crib widths) by 6 feet thick, and rises approximately 24 feet at its height and 20 feet in the middle. Gunnite was applied to a central crib to form a spillway/pour-over location. The lower concrete sill below the dam rises roughly 3 feet above the channel surface. Between the dam and sill, as well as south of the sill, the hillside to the east and west are both covered with gunnite to stabilize the hillside. On the west hillside gunnite slurry wall, however an oak tree is actively growing out a large crack and concavity in the slurry wall, showing a wall thickness of roughly 2 inches. One concrete beam on the upper right side of the dam bears the incised mark of “USFS 1970 E 4” and a metal plaque from the LACFCD. A pair of metal bars are attached to right side of the dam face, to act as ladder with the crib beams as rungs.

Item #8. Page 982
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DPR 523L (Rev. 1/1995)(Word 9/2013) *Required information State of California  Natural Resources Agency Primary# DEPARTMENT OF PARKS AND RECREATION HRI #
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South of the crib dam, a gunnite-lined channel meanders south towards a culvert along Palm Drive. The channel width varies along the length with a shallow smooth-bottomed basin shape approximately 30 feet wide immediately below the dam. 200 feet south of the dam, the channel is a steep V-shape, 16 feet wide and 5 feet deep. 550 feet south of the dam, the channel is a steep V-shape, 10 feet wide and 5 feet deep (Figure Y). 900 feet south of the dam, a dirt road crosses the channel and the channel walls slope to accommodate the road; here the channel is 0 feet deep and 12 feet wide. At the culvert along Palm Drive, the channel is 8 feet wide and 6 feet deep.

Figure 3. East crib dam, looking north (IMG_1320)
Item #8. Page 983
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DPR 523L (Rev. 1/1995)(Word 9/2013) *Required information State of California  Natural Resources Agency Primary# DEPARTMENT OF PARKS AND RECREATION HRI #
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Property Name: ___ USFS/LACFCD Dams and channel _____________________________________________________ Page __7__ of __10__
Figure 4. Concrete lined channel, 550 feet south of dam, looking north (IMG_4019) Identified Alterations
No permits were available from the Los Angeles County Department of Public Works for the concrete crib dams or channel. No observed alterations were noted in the course of survey. The crib dams are in fair condition, but heavily overgrown by vegetation and the debris cone behind each dam has completely filled and level to the top of each dam.

B6. Construction History (continued): Los Angeles County Flood Control District and Forest Service Crib Dams (circa 1969-present)
In 1968, a large wildfire in the foothills north of Glendora and Azusa burned 20,000 acres and decimated the underbrush and trees. The following January through March 1969, Glendora experienced heavy rains which led to flooding, devastating mudslides, and cascading boulders damaging homes and schools. Mudslides were especially damaging along Rainbow Drive, just two blocks east of Grand Avenue. Glendora sought relief and received $1.5 million in federal aid. One of the first projects to go through was the $340,000 debris control dam and basin just west of the proposed project APE in Hook Canyon, started in 1969. In spring 1970, City of Glendora, US Army Corps of Engineers, Los Angeles County Flood Control District (LACFCD), and the USDA Forest Service (USFS) began constructing 45 concrete crib dams in 15 canyons north of Glendora (Figure 10). The purpose of the crib dams was to allow debris and soil to accumulate behind the dams while allowing water through. Still more erosion control measures were taken by instating planting programs, and seeding areas of then 1968 burn scar. These efforts were rewarded in 1974 (LAT 1969b, 1969c, 1970; Pasadena Independent 1968; USFS 1975).

Item #8. Page 984
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DPR 523L (Rev. 1/1995)(Word 9/2013) *Required information State of California  Natural Resources Agency Primary# DEPARTMENT OF PARKS AND RECREATION HRI #
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Property Name: ___ USFS/LACFCD Dams and channel _____________________________________________________ Page __8__ of __10__
Figure 5. USFS employees constructing a concrete crib dam north of Glendora. (Los Angeles Times 1970)
B10. Significance (continued): NRHP/CRHR Statement of Significance Criterion A/1: That are associated with events that have made a significant contribution to the broad patterns of our history.

The three crib dams and channel were constructed in 1970 in response to a 1968 fire and subsequent flooding and mudslides in 1969, in order to prevent further damage to the residential subdivisions of City of Glendora, which had been slowly reaching further and further north into the San Gabriel Mountain foothills. Though the 1969 fire was a substantial fire and brought about positive civil infrastructure changes, the fire and flood is one of many in the history of Glendora and its damages were not particularly exceptional or historic in their proportions. Fire and flood/mudslide patterns were typical to this area and most down-stream communities south the canyon outlets of San Gabriel Mountains. The crib dams were constructed as part of a larger joint USFS and LACFCD infrastructure program which created the larger Hook Canyon debris dam and channel, as well as 40 other concrete crib dams. AS such, the dams on the subject property do not distinguish themselves as particularly important structures that made a significant contribution to the broad patterns of local Glendora history. Therefore, the three crib dams and channel do not appear eligible under NRHP/CRHR Criterion A/1.

Item #8. Page 985
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DPR 523L (Rev. 1/1995)(Word 9/2013) *Required information State of California  Natural Resources Agency Primary# DEPARTMENT OF PARKS AND RECREATION HRI #
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Criterion B/2: That are associated with the lives of persons significant in our past.

Archival research failed to identify any associations with significant persons. Due to a lack of identified significant associations with important persons in history, the subject property does not appear eligible under NRHP/CRHR Criterion B/2.

The three dams and channel were constructed in 1970 as a joint project between USFS, LACFCD, with financial aid from the Army Corps of Engineers and the City of Glendora.

They are typically constructed of concrete beams arranged in cribs and built to various heights. Crib dams were not a new, novel, or improved engineering method for dealing with debris floods. The technique of using crib dams to control land erosion and heavy sediment flow originated in Europe and was used in the San Gabriel Mountains by the USFS as early as 1915. Because the dams are meant to slowly backfill, the multiple historical flood events in Los Angeles (1916, 1938) eventually covered and made obsolete earlier crib dams. Multiple crib dam building periods were identified by the USFS as important projects: a concrete arch check dam in Arroyo Seco Canyon (1942); the Coon Canyon Stabilization Project (1950); and the Los Angeles River Watershed Project (1954-1974), however this last did not provide crib dams in Glendora. The three crib dams in the study area are typical in their construction and offer no insight into engineering techniques or identified major projects. Archival research did not indicate an association between the dams and channel and a master engineer. The dams are of utilitarian construction and do not possess artistic value. While the dams and channel are part of an entity of dams built after the 1969 mudslides and flood, they are neither significant or distinguishable from earlier period crib dams constructed for similar regions throughout the San Gabriel National Forest. Therefore, the crib dams and channel not appear eligible under NRHP/CRHR Criterion C/3.

Criterion D/4: That have yielded, or may be likely to yield, information important in prehistory or history.

The subject property is not likely to yield information important to understanding prehistory or history. Therefore, the subject property does not appear eligible under NRHP/CRHR Criterion D/4.

City of Glendora Historic Resource or Landmark Designation Criteria

1. The proposed preserved features exemplify or reflect special elements of historical, architectural, archaeological, cultural, or aesthetic heritage.

The three crib dams and channel are utilitarian in construction and constructed by the USFS and LACFCD in 1970, in response to a flood and mudslide event in 1969. However, in the larger Glendora-area history this flood and mudslide event was one of many in Glendora’s history, and resulted in the construction of 40 similar structures. These structures neither exemplify nor reflect special elements of historical, architectural, archaeological, cultural, or aesthetic heritage of Glendora. Therefore, the crib dams and channel are not eligible as a City of Glendora Historic Resource or Landmark under Criterion 1.

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2. The proposed preserved features are identified with persons or events significant in local, state, or national history.

Archival research failed to identify any associations with significant persons at the local, state, or national level. Therefore, the crib dams and channel are not eligible as a City of Glendora Historic Resource or Landmark under Criterion 2.

3. The proposed features embody distinctive characteristics of a style, type, period or method of construction or are valuable examples of the use of indigenous materials or craftsmanship.

4. The proposed preserved features are representative of the notable work of a builder, designer or architect.

Integrity Discussion
All three dams and the channel maintain integrity of location and setting as neither have changed since their construction in 1970. The dams have infilled, however there appear to be no notable alterations, repairs, demolitions, or additions, and therefore the three dams and channel maintain integrity of design, materials and workmanship. The dams and channel still evoke the feeling of utilitarian flood control structures and therefore retain integrity of feeling. Though the dams retain signage by USFS and LACFCD, they appear to not be actively maintained and do not retain integrity of association.

B12. References (continued):

LAT (Los Angeles Times). 1969a. “Foothills Might Have Been Spared the Flood.” Newspapers.com: The Los Angeles Times. April 6, 1969, pg. 198.

LAT. 1969b. “Debris Control Dam to Be Built.” Newspapers.com: The Los Angeles Times.

May 11, 1969, pg. 153.

LAT. 1969c. “Watershed Flood Work Will Be Undertaken.” Newspapers.com: The Los Angeles Times. October 30, 1969, pg. 136.

LAT. 1970. “Crib Dams.” Newspapers.com: The Los Angeles Times. July 19, 1970, pg. 230.

Pasadena Independent. 1968. “Glendora 6-day Fire Contained.” Newspapers.com: Pasadena Independent. August 29, 1968, pg. 26.

USFS (US Forest Service). 1975. “Concrete Crib Check Dams.” Engineering Technical Information System: Field Notes. Volume 7, Number 6, revised. Published June 1975, accessed August 9, 2019. https://www.fs.fed.us/td/pubs/pdfpubs/pdf75713806/pdf75713806.pdf Item #8. Page 987
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Appendix D
MWD Letter
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Item #8. Page 989
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Office of the General Manager
700 N. Alameda Street, Los Angeles, California 90012  Mailing Address: Box 54153, Los Angeles, California 90054-0153  Telephone (213) 217-6000 MWD Upper Feeder
Sta. 2252+00 to 2257+44
Substr. Job No. 2002-14-004
July 8, 2019
Ms. Amy L. Bledsoe, PE, PLS, QSD
Giron Engineers, Inc.
654 South Glendora Avenue
Glendora, CA 91740
Dear Ms. Bledsoe:

Tentative Tract Map No.72413 – Revised Plans
Thank you for your email dated June 25, 2019, submitting prints of your revised preliminary site development plans (Sheets 1 through 4 of 4), for the proposed development located generally north of Palm Drive and Grand Avenue in the city of Glendora. Included with your submittal was a response to our letter dated June 6, 2019.

Metropolitan wants to state our condition throughout the engineering review process for your proposed development, which includes but is not limited to, grading and utilities over our pipeline easement, which is subjected to granting Metropolitan an unrestricted access easement for ingress and egress from Palm Drive by means of tract map recordation. Please submit a copy of the Tract Map for our review prior to final acceptance and recordation.

We have reviewed your revised plans, and our comments and requirements are as follows:

1. The locations of Metropolitan’s 10-foot-3-inch-inside-diameter precast concrete Upper Feeder pipeline, appurtenant manhole structures, accompanying 40-foot-wide permanent easement, and 100-foot-wide tunnel easement right-of-way, as shown on all pertinent sheets of your plans, are generally in agreement with our records.

2. We understand that a soils report and/or settlement analysis showing the predicted settlement of our pipeline at 10-foot intervals along with the method of settlement analysis, laboratory testing results and any other supporting documents must be submitted Item #8. Page 990
Meeting Date: 1/24/2023 / Packet Page #: 1055
Ms. Amy L. Bledsoe

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July 8, 2019
for our review, as noted in Item 10 of “Metropolitan Water District Notes” on Sheet 2 of 4 of your revised preliminary site development plans.

3. We note that provision for a 16-foot-wide driveway approach centered over our pipeline is provided on the north side of the road intersecting our right-of-way. A 10 percent unpaved access ramp will also be provided from the driveway approach. Gates or removable bollards, capable of accommodating Metropolitan’s locks, must be installed at this location to prevent unauthorized entry to our right-of-way.

4. We note that the location of the 6-foot-high retaining wall has been revised approximately 4 feet north of our manhole structure (at our Station 2256+93), as shown on Sheet 2 of 4 of your revised preliminary site plans, is acceptable to Metropolitan. We would like to request that bollards be placed on the south side of City of Glendora Flood Control’s maintenance road to protect Metropolitan 10-foot-inside-diameter air vent shaft (at our Station 2280+51) from damage.

Please provide details of the retaining wall, foundations, and supporting calculations stamped and signed for our review and written approval.

5. Please submit detail of the non-potable utility with the required secondary containment for our review, when available.

6. We note you have included provisions for construction and notification of Metropolitan on Sheet 2 of 4 of your revised preliminary site development plans. Please revise minor typo on Item 3 as “MWD Access” and on Item 8 “When the cover is between 3 and 4 feet, equipment must be restricted to that which imposes no loads greater than AASHTO H-20 loading.”
Provided that the settlement analysis is submitted for the proposed fill over our pipeline and right-of-way for our review and subject to the grant of access of easement to Metropolitan, your plans are generally acceptable to Metropolitan. We are returning prints of Sheets 1 through 4 of 4 of your revised preliminary site development plans Tentative Tract Map No. 72413, stamped “REVIEWED — CORRECTIONS NOTED — NO RESUBMITTAL REQUIRED.” Plans for any landscaping or other improvements proposed within our right-of-way must also be submitted for our review and written approval. Please note that no structures of any kind or trees are allowed within the limits of our right-of-way, but ground cover is permitted. The landscape plans must contain provisions to maintain access along our right-of-way.

Facilities constructed within Metropolitan’s easement shall be subject to the paramount right of Metropolitan to use the easement for the purpose for which it was acquired. If at any time Metropolitan or its assigns should, in the exercise of their rights, find it necessary to remove any Item #8. Page 991
Meeting Date: 1/24/2023 / Packet Page #: 1056
Ms. Amy L. Bledsoe

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July 8, 2019
of the facilities from the easement, such removal and replacement shall be at the expense of the owner of the facility.

Please note that access to Lots 7, 8, and 9 immediately to the northeast of our pipeline and right-of-way could be unavailable at any time, for a period of time, in the event excavation of our pipeline becomes necessary for maintenance and repair, replacement, or the addition of another pipeline. Metropolitan will not be responsible for any disruptions to the access if this were to occur.

For any further correspondence with Metropolitan relating to this project, please make reference to the Substructures Job Number shown in the upper right-hand corner of the first page of this letter. Should you require any additional information, please contact Ken Chung, telephone (213) 217-7670.

Very truly yours,
Shoreh Zareh, P.E.

Manager, Substructures Team
KC/mc
DOC#: 2002-14-004c
Enclosures (4)

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Meeting Date: 1/24/2023 / Packet Page #: 1057
Ms. Amy L. Bledsoe

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July 8, 2019
cc: City of Glendora w/plans
Engineering Division
116 East Foothill Boulevard
Glendora, CA 91741-3380

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Appendix D
Geotechnical Investigations
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40 0 40 80 120 Scale in Feet GEOLOGIC MAP
Dreamland Investments, LLC
Three Debris Basins/Dams and Access Roads
Development Remaining Parcel, APN 8684-045-004
Glendora, California
G. A. Nicoll & Associates, Inc.

Project No.: Date: Plate No: Geologic & Soils Engineers Tustin, California
6950-04 Feb 2016 1

GEOLOGIC MAP

GEOLOGIC KEY UNITS SYMBOLS
FILL Qal Qls Qls? Cgr Qcol Qalo
Fill, undocumented Boring, showing
total depth
Boring, PN 6817-04,
showing total depth
Test Pit, showing
total depth Test Pit, PN 6817-04, showing total depth
Geologic Contact, queried
where approximate, dotted where buried Geologic Cross Section Temporary Drill Pad Cuts
Strike and Dip of Shear -
surface exposure
Strike and Dip of Shear,
showing depth in boring
Strike and Dip of Fracture,
showing depth in boring or
test pit
Seepage, showing depth in
boring
Water level in boring
Strike and Dip of Fracture - surface
exposure Alluvium
Colluvium
Slump, arrows show direction of movement Soil Slip Old Alluvium Qt Terrace Deposits Landslide Questionable Landslide Cretaceous-age Granitic Rocks (Granodiorite) B-9B-9
26' 5' 28' 7' TP-9 TP-26 ?22 22' 75
24' 60
41' 55
77 24' 22'
Qcol Qcol
Qcol
Qcol
Qcol
Qcol
Qcol
Qcol Qcol
Qcol Qcol
Qcol
Qcol
Qcol
Qcol
Qcol
Qcol
Qcol
Qcol
Qcol
Qcol
Qcol
Qcol
Qt
Qt
Qt
Qt
Qt
Qt
Qt
Qt
Qt
Qt
Qt
Qt
Qt
Qt
Qt
Cgr
Cgr
Cgr
Cgr
Cgr
Cgr
Cgr
Cgr
Cgr
Cgr
Cgr
Cgr
Cgr
Cgr
Cgr
Cgr Cgr
Cgr
Cgr
Cgr
Cgr
Cgr
Cgr
Cgr
Cgr
Cgr
Cgr
Cgr
Cgr
Cgr
Cgr Cgr
Cgr
Cgr
Qal
Qal
Qal
Qal Qls?
FILL FOR 10-FT. DIA. WATER PIPE

EXISTING MWD EASEMENT

TUNNEL AIR VENT ABANDONED WATER

TANK SHELL EXISTING EROSION

STRUCTURE
FOR MONROVIA NO. 1 TUNNEL EXISTING MWD EASEMENT PROPOSED WEST DEBRIS

BASIN AND DAM
D R P

PROPOSED MIDDLE DEBRIS

BASIN AND DAM

PROPOSED EAST DEBRIS

BASIN AND DAM
9 PL
PL
PL
PL
PL
PL
ABANDONED SUBTERRANEAN WATER TANK SHELL ABANDONED METAL SPA SHELL EXISTING WALLS B-1 B-3 B-4
B-6 B-5 B-2 B-7
35'
50' 46'
28'
70'
41'
55' B-8 B-9
40' 36' B-1
27' B-2 55' B-9 B-7
28' 51' 4' TP-5 TP-6 TP-20 TP-22 TP-23 TP-4 TP-11 TP-12 TP-14 TP-21 TP-25 TP-15 TP-26 TP-13 14' 11' 6' 7' 7' 10' 6'
TP-19
8' 3' 12' 7'
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Appendix E
Hydrology Study
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HYDROLOGY STUDY

FOR THE
TENTANTIVE TRACT 72413

SILENT RANCH DEVELOPMENT
ESTU2016000096
North Grand Avenue and
West Palm Drive
Glendora, CA
APN 8684-045-004
Prepared For:

DREAMLAND INVESTMENTS, LLC.

Alan Chou
654 South Glendora Avenue
Glendora, California 91740
(626) 236-7388
[email protected]
Prepared By:

WEST CONSULTANTS, INC.
8950 S. 52nd Street, Suite 210
Tempe, AZ 85284
(480) 345-2155
August, 2018

HYDROLOGY STUDY
CITY OF _____________________________

RECOMMENDED FOR CITY APPROVAL
CHECKED BY:______________________RCE NO._________DATE___________ APPROVED BY:_____________________________________DATE___________

COUNTY OF LOS ANGELES DEPARTMENT OF PUBLIC WORKS

LAND DEVELOPMENT DIVISION
88200
2/27/2019
2/27/2019

GLENDORA

HYDROLOGY STUDY
APPROVED BY CITY OF ________________
APPROVED BY:_____________________RCE NO._________DATE___________ GLENDORA Item #8. Page 1235
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HYDROLOGY STUDY TENTATIVE TRACT 72413
1 Executive Summary
This hydrology study analyzes the pre- and post-developed conditions for proposed Silent Ranch Development (Tentative Tract 72413) in Glendora, California. The project consists of 12 new single-family homes. The site is bounded by offsite mountainous terrain to the north which contributes to the overall watershed area and is bounded to the south by an existing urban residential development to the south which includes an active storm drain system. The City of Glendora has required that the proposed development adhere to their Best Management Practices (BMP) and Low Impact Development (LID) requirements.

Offsite debris flows to the proposed development are a concern, particularly because the undeveloped area is considered a burned watershed. Accordingly, the offsite debris concerns will be addressed by constructing three debris containment structures.

All hydrology and debris calculations were performed with and all proposed design elements adhere to the Los Angeles County Department of Public Works (LACDPW) Hydrology Manual (2006) and the LACDPW Sedimentation Manual (2006). Runoff from the subdivision will not exceed existing conditions for the specified design events nor will flow to the existing storm drain exceed the project specific LACDPW specified allowable rate.

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2 Contents

1. Introduction ...........................................................................................................................................................5

2. Project Description.................................................................................................................................................5

3. Requirements.........................................................................................................................................................7

3.1. Hydrology........................................................................................................................................................7

3.2. Burned flows and Debris.................................................................................................................................7

3.3. Flooding...........................................................................................................................................................7

3.3.1. Flood Protection.......................................................................................................................................7

3.3.2. Outflow to the Existing Public Storm Drain .............................................................................................8

3.3.3. Mitigation for hungry water ....................................................................................................................8

4. Existing Condition ..................................................................................................................................................9

4.1. Proximity to existing floodplains and/or floodways.......................................................................................9

4.2. Fire factor........................................................................................................................................................9

4.3. 50-year 24-hour Isohyets................................................................................................................................9

4.4. Subarea Characteristics.................................................................................................................................10

4.4.1. Drainage subareas..................................................................................................................................10

4.4.2. Debris production rate and bulking factor.............................................................................................10

4.4.3. Soil types................................................................................................................................................12

4.4.4. Geometric characteristics......................................................................................................................13

4.4.5. Percent impervious................................................................................................................................13

4.4.6. Summary of subarea characteristics......................................................................................................14

4.5. Time of concentration calculation ................................................................................................................14

4.6. Routing analysis ............................................................................................................................................14

5. Proposed Condition .............................................................................................................................................18

5.1. Overall approach...........................................................................................................................................18

5.2. Proposed Subareas .......................................................................................................................................19

5.2.1. Hydrologic parameters ..........................................................................................................................19

5.2.2. Time of concentration calculation .........................................................................................................20

5.2.3. Routing analysis .....................................................................................................................................20

5.3. Comparison of existing condition versus proposed condition peak flows...................................................24

6. Debris protection measures.................................................................................................................................26

6.1. Debris containment design ...........................................................................................................................26

7. Conclusion............................................................................................................................................................28

8. References ...........................................................................................................................................................29 Item #8. Page 1237
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3 Appendices
Appendix A. Allowable Outflow..............................................................................................................................A-1 Appendix B. City of Glendora Onsite Flow Approval ..............................................................................................B-1 Appendix C. Hydrologic Calculations ......................................................................................................................C-1 Appendix D. Hydraulic Calculations........................................................................................................................D-1 Appendix E. LACDPW Allowance for Construction of West Basin as an Elevated Inlet.......................................... E-1 Appendix F. Maps.................................................................................................................................................... F-1 List of Tables
Table 1. Debris production rates and bulking factor ...............................................................................................12 Table 2. Weighted bulking factors and debris production for Subarea A8-1 ..........................................................12 Table 3. Weighted bulking factors and debris production for Subarea A8-2 ..........................................................12 Table 4. Weighted bulking factors and debris production for Subarea A10-1 ........................................................12 Table 5. Weighted bulking factors and debris production for Subarea A10-2 ........................................................12 Table 6. Weighted imperviousness for Subarea A8-1..............................................................................................13 Table 7. Existing condition subarea design data......................................................................................................14 Table 8. Cumulative bulking factor at subarea A8-1................................................................................................15 Table 9. Cumulative bulking factor at subarea A8-2................................................................................................15 Table 10. Cumulative bulking factor at CP-1............................................................................................................15 Table 11. Cumulative bulking factor at subarea A10-1............................................................................................15 Table 12. Cumulative bulking factor at subarea A10-2............................................................................................15 Table 13. Cumulative bulking factor at subarea CP2 ...............................................................................................15 Table 14. Existing condition cumulative areas at LAR04 concentration points.......................................................16 Table 15. Summary of routed flows under the existing condition ..........................................................................17 Table 16. Proposed condition hydrologic design data and debris production of offsite subareas.........................20 Table 17. Detention analysis results: 25-year storm (Urban Flood) .......................................................................21 Table 18. Detention analysis results: 50-year storm (Capital Flood)......................................................................21 Table 19. Detention analysis results: 50-year storm (Capital Flood Burned Flows) ...............................................21 Table 20. LAR04 Model B, Proposed condition subareas B1 – B3 cumulative areas at LAR04 concentration points .................................................................................................................................................................................23 Table 21. LAR04 Model C, Proposed condition subareas C, F, and H cumulative areas at LAR04 concentration points .......................................................................................................................................................................23 Table 22. LAR04 Model D, Proposed conditions subareas D1 – D3 cumulative areas at LAR04 concentration points .......................................................................................................................................................................23 Table 23. Proposed condition cumulative areas at LAR04 concentration points..................................................23 Table 24. Proposed conditions routing analysis summary ......................................................................................24 Table 25. Comparison of outflows...........................................................................................................................24 Table 26. Estimates of design outflows to the public storm drain ..........................................................................25 Table 27. Debris containment details......................................................................................................................27 List of Figures
Figure 1. Project vicinity map (not to scale) ..............................................................................................................5 Figure 2. Existing debris wall north of proposed development.................................................................................6 Figure 3. Site location on FEMA Floodplain Map 06037C1440F................................................................................9 Figure 4. 50-year, 24-hour isohyet, DPA, and soil types..........................................................................................10 Figure 5. Los Angeles Basin Debris Production Rates – from the LACDPW Sedimentation Manual (2006)............11 Figure 6. Los Angeles Basin Peak Bulking Factors – from the LACDPW Sedimentation Manual (2006)..................11 Item #8. Page 1238
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4 Figure 7. Existing condition routing schematic in LAR04. .......................................................................................16 Figure 8. Flow split schematic .................................................................................................................................19 Figure 9. Proposed condition outflow routing schematic for LAR04.......................................................................22 Figure 10. Elevated Inlet B Profile Schematic (not to scale) ...................................................................................26 Figure 11. Elevated Inlet C Profile Schematic (not to scale) ...................................................................................26 Figure 12. Debris Basin D Profile Schematic (not to scale) .....................................................................................27 Item #8. Page 1239
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HYDROLOGY STUDY TENTATIVE TRACT 72413
5 1. Introduction
This report presents the details of a hydrology study on the proposed Silent Ranch Development (Tentative Tract 72413) located in the City of Glendora, CA (Figure 1). This project has spent several years in development due to the highly complex nature of the offsite flows and debris basin requirements. It is the intent of the developer of the project – Dreamland Investments, LLC (Dreamland) – to protect the community from offsite debris flows by constructing major infrastructure including elevated inlets, access roads, and a high capacity storm drain system.

Due to the high cost of the project, the project team of Dreamland, Giron Engineers, Inc. (Giron) and WEST Consultants, Inc. (WEST) all hope to meet or exceed all LACDPW requirements for this hydrology report, thereby facilitating approval and construction of this important project.

2. Project Description
The proposed subdivision is located north of Palm Avenue in the City of Glendora, California (Figure 1) and consists of 26.9 acres of largely undisturbed area as well as mountainous terrain to the north, resulting in a current total drainage area of 51.5 acres. Following construction, a total area of 53.1 acres is expected to drain through the site (See 8.Appendix F). The site is bordered to the west and south by residential development.

Access to the site is from Palm Drive.

Figure 1. Project vicinity map (not to scale)
Project Site
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HYDROLOGY STUDY TENTATIVE TRACT 72413
6 The project area itself consists of 14 lots composed of one existing lot (Lot 1 – will not be modified), one lot that encompasses the subdivision private drive (Lot 4), and 12 lots consisting of new single-family home units (Lots 2 3, and 5 – 14). All street access and infrastructure will be built in compliance with Los Angeles County and City of Glendora zone codes and ordinances.

The existing project watershed (tributary area) is mostly natural and undeveloped. Steep (> 20%) slopes characterize the upper areas of the watershed. Three debris control and channel stabilization structures were installed by the United States Forestry Service (USFS) in 1970. They have since been completely filled and are at capacity. (Figure 2 shows one of these existing dams.) Hence, under current conditions no debris or water retention occurs and runoff from the upper watershed spills freely over the structures.

Figure 2. Existing debris wall north of proposed development After overtopping the existing structures, storm runoff and debris currently flows southeasterly through the existing watershed to a confluence at Grand Avenue near Palm Drive. Existing flows then splits, with some amount draining into the existing 39-inch diameter reinforced concrete pipe (RCP) storm drain pipe along Grand Avenue (MTD 0849) but the majority of the flow spilling into the streets. Calculations by LACDPW indicate that the existing storm drain has some capacity for flows from the site. It will be shown that this capacity in conjunction with proposed street conveyance capacity should be sufficient to convey flows from the design events.

The proposed project will address the offsite debris issues and will attenuate peak inflows by constructing three large debris containment facilities within the subdivision property and north of the developed area. The containment slopes will be protected according to the site geotechnical report performed by G.A. Nicoll and Associates, (G. A. Nicoll and Assocociates Inc., 2016).

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HYDROLOGY STUDY TENTATIVE TRACT 72413
7 3. Requirements

3.1. Hydrology
The analysis described herein adheres strictly to the LACDPW Hydrology Manual (2006) and specific instructions issued by with LACDPW personnel during the project. Times of concentration for both proposed and existing conditions were determined using the LACDPW software Hydrocalc, version 1.0.2 (LACDPW, ND). Hydrocalc is an application of the modified rational method. Hydrocalc is limited to subareas smaller than 40 acres; accordingly, the subarea designations applied here for both existing and proposed conditions have been kept less than 40 acres.

The times of concentration as determined by Hydrocalc were then used in conjunction with the other sitespecific data to route the subareas via the LACDPW accepted LAR04 software (CivilDesign, 2017). The LAR04 accompanying software program “Retard” was used to analyze the reduced peak flows the result from routing the hydrographs through the debris containment facilities, which reduced predicted peak outflows by means of detention. Because Retard is part of the LAR04 software package it is approved for use by the LACDPW.

All hydrology software output (Hydrocalc, LAR04, and the Retard program) is included here in Appendix C.

3.2. Burned flows and Debris
The proposed development is within mountainous terrain and therefore LACDPW requires the calculation of sediment (debris) flow, as per the LACDPW Sedimentation Manual (2006). Debris production is computed by a ‘rate of sedimentation’ in units of cubic yards/square mile/ design event. The potential for debris production of site is characterized by an area’s the Debris Potential Area (DPA) zone. The Design Debris Event (DDE) is defined as sediment produced by saturated watershed significantly recovered (approx. 4 years) from a burn due to a 50 year, 24-hour rainfall event. Debris production curves characterize the debris produced for each DPA zone by the DDE as a function of area. The curves account for the specific geologic, topographic, vegetation and rainfall characteristics of the site. The total debris production for a watershed is thus the product of the production rate/ square mile and the area of the watershed.

Bulked flows, or the increase in flow rate due to inclusion of sediment in the flow, are computed as well. Bulked flows are a function of an area’s ‘burned’ flow. Burned flow is a function of the fire factor which characterizes the study area (discussed in section 4.2.).

In the same way as debris production curves characterize sedimentation rate for each DPA zone, bulking factor curves show the proportion of the bulked rate to burned rate (a bulking factor) for a given subarea. These curves are figures 3.4 and 3.1 of the Sedimentation Manual (LACDPW, 2006).

3.3. Flooding

3.3.1. Flood Protection
Several levels of flood protection are required for this development. Specifically, the total routed clear water peak outflow from the developed site must not exceed the existing peak clear water flow for two events:

1. The Urban Flood. The Urban Flood corresponds to the 25-year frequency design storm incident to a saturated watershed.

2. The Capital Flood. The Capital Flood corresponds to the 50-year frequency design storm incident to a saturated watershed.

Additionally, capital flood protection also requires the effects of fires and erosion to be accounted for, so that the burned and bulked flow condition for the 50-year frequency is calculated as well.

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HYDROLOGY STUDY TENTATIVE TRACT 72413
8 3.3.2. Outflow to the Existing Public Storm Drain
The peak outflow to the existing public storm drain system cannot exceed the allowable flowrate as determined by the LACDPW. Specifically, the LAPDPW requires that the post development burned flow entering the storm drain system be limited to 1.74 cfs / acre based on the existing (pre-development) drainage area (Appendix A).

The proposed site has a total existing drainage area of 51.5 acres, and hence the total allowable flow from the site to the existing storm is Qallowable = (1.74)(51.5) = 89.6 cfs. This requirement was implemented by designing an onsite storm drain system that will direct 89.6 cfs of the debulked offsite flow to the public storm drain. The remaining debulked offsite flow and all of the onsite flow will outlet to the street system along the historical flow path.

3.3.3. Mitigation for hungry water
Sites with hungry water are typically required to enact mitigation measures. Here, all inflows into the proposed lot developments are expected to be both burned and bulked and hence are sediment laden rather than sediment starved. Hence, mitigation for hungry water is not expected to be a concern.

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HYDROLOGY STUDY TENTATIVE TRACT 72413
9 4. Existing Condition

4.1. Proximity to existing floodplains and/or floodways The proposed site is outside of any mapped floodplain or floodway. As shown in Figure 3, the applicable Federal Emergency Management Agency (FEMA) Floodplain Map (Panel 1440, Number 06037C1440F, effective date 09/25/2008) shows the site to be in Zone D, corresponding to an area where no analysis of flood hazards has been conducted.

Figure 3. Site location on FEMA Floodplain Map 06037C1440F

4.2. Fire factor
The project site is in the San Gabriel River Watershed. Accordingly, the fire factor at this location is 0.71 per Table 6.3.3 in the LACPDW Hydrology Manual (2006). The fire factor is applied to the peak flow rate (clear) to determine the burned peak flow rate.

4.3. 50-year 24-hour Isohyets
Hydrologic maps provided in the LACDPW Hydrology manual (2006) depict the 50-year, 24-hour isohyet, DPAs, and soil types (Figure 4). For the present site, the 50-year, 24-hour Isohyet is seen to be between 8.1 and 8.3 inches. Here, the higher value (8.3 inches) was assumed throughout the site for both proposed and existing conditions.

Proposed Site
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10 Figure 4. 50-year, 24-hour isohyet, DPA, and soil types

4.4. Subarea Characteristics

4.4.1. Drainage subareas
The existing site was subdivided into thirteen undeveloped subareas, denoted by A1 through A10-2. One subarea is mixed use, denoted as subarea A8-1 , and one is a developed subarea (Lot1b). All of these subareas have been delineated to meet the LADPW requirement that longest flow path lengths be no more than 1,000 feet. The subarea delineation is shown in Map 1 in Appendix F, and details of the subareas have been summarized in Table 7 below.

4.4.2. Debris production rate and bulking factor
The existing watershed is characterized by DPA zones 1 and 7 as identified in Figure 4. These zones were used in conjunction with the LACDPW Sedimentation Design Manual Figures B1 and B4, reproduced here as Figure 5 and Figure 6, respectively, to determine the debris production rate (DPR) and bulking factor for the existing designated subareas. About 90% of the project area is in DPA zone 1; 10% is in DPA zone 7. The areas of all designated subareas as far less than the minimum of 0.1 square miles shown in the curves. Therefore, the minimum allowable values of bulking factor and DPR for the two DPA zones were used. These are listed in Table

1. Item #8. Page 1245
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HYDROLOGY STUDY TENTATIVE TRACT 72413
11 Figure 5. Los Angeles Basin Debris Production Rates – from the LACDPW Sedimentation Manual (2006) Figure 6. Los Angeles Basin Peak Bulking Factors – from the LACDPW Sedimentation Manual (2006) 240,000
28,000

1.567

2.000
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HYDROLOGY STUDY TENTATIVE TRACT 72413
12 Table 1. Debris production rates and bulking factor
Design Parameter DPA Zone 1 DPA Zone 7
Bulking Factor 2.000 1.567
DPR (yd³ /mi2) 240,000 28,000
Subareas A1 through A7 and subarea A9 are characterized by DPA zone 1 only and hence each have a DPR of 240,000 yd /mi . Subareas A8-1 A8-2 A10-1 A10-2 require weighted bulking factors and debris production because they span both DPA Zones 1 and 7. These computations are shown in Table 2 and Table 4, below.

Subarea Lot1b is developed and non-debris producing and hence neither the bulking factor nor the debris production rates are applicable to it.

Table 2. Weighted bulking factors and debris production for Subarea A8-1 Area Types Area (ac)
Bulking
Factor
Weighted
Factor
Debris Production Rate
(yd /mi²)
Weighted Debris
Production Rate
(yd³/mi²)
Zone 1 3.2 2.000 1.633 240000 196000
Zone 7 0.7 1.567 0.287 28000 5000
Totals: 3.9 1.921 201000
Table 3. Weighted bulking factors and debris production for Subarea A8-2 Area Types Area (ac)
Bulking
Factor
Weighted
Factor
Debris Production Rate
(yd /mi²)
Weighted Debris
Production Rate
(yd³/mi²)
Zone 1 4.6 2.000 1.832 240000 220000
Zone 7 0.4 1.567 0.131 28000 2000
Totals: 5.1 1.963 222000
Table 4. Weighted bulking factors and debris production for Subarea A10-1 Area Types Area (ac)
Bulking
Factor
Weighted
Factor
Debris Production Rate
(yd /mi²)
Weighted Debris
Production
(yd³/mi²)
Zone 1 0.2 2.000 0.172 240000 21000
Zone 7 1.5 1.567 1.433 28000 26000
Totals: 1.7 1.604 46000
Table 5. Weighted bulking factors and debris production for Subarea A10-2 Area Types Area (ac)
Bulking
Factor
Weighted
Factor
Debris Production Rate
(yd /mi²)
Weighted Debris
Production
(yd³/mi²)
Zone 1 0.2 2.000 0.351 240000 42000
Zone 7 1.2 1.567 1.29 28000 23000
Totals: 1.4 1.643 65000
All existing subarea bulking factors and debris production is summarized in Table 7 below.

4.4.3. Soil types
Like the DPA zones, the existing watershed soils are characterized by two types, 007 (Hanford gravelly sandy loam) and 081 (Upper San Gabriel river USGR-G-1) (see Figure 4 above). The LACDPW authorized software used Item #8. Page 1247
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13 for this project allows one soil type to be entered for the runoff calculation of each subarea, so the soil type which makes up the majority of the area was selected for each watershed (Table 7).

4.4.4. Geometric characteristics
The geometric characteristics were determined for each subarea is as follows:

1. Area. The total drainage area in acres was estimated.

2. Longest flow path length. In order to determine time of concentration, the drainage path with the longest travel time was estimated for each subarea.

3. Longest flow path slope. The longest flow path slope was determined by dividing the total elevation change divided by the total flow length. This was used in the time of concentration calculation.

4. Routing flow path length. In order to correctly route flow from the subareas, the routing flow path was determined. The routing flow path is the path taken from inflow to the subarea to its outlet point. Note that this is different than the longest flow path and there will be multiple flow paths within a subarea if more than one upgradient subarea drains to it. The routing flow lengths are shown in Map 1 in Appendix F.

5. Routing flow path slope. In order to correctly estimate routing times for inflow from upgradient subareas, the routing flow path slope was determined. The routing flow path slope was determined by dividing the total elevation change along the path divided by the total flow length. Note that this is different than the longest flow path slope.

All subarea geometric estimates are summarized in Table 7 below.

4.4.5. Percent impervious
The percent impervious is a function of the land use category of the site. Land use categories and their associated percent impervious are tabulated in Appendix D of the LAPDW Hydrology Manual (2006). The existing watersheds are characterized by two land use types: Vacant Undifferentiated and Low Density Single Family Residential. The corresponding percent impervious is 1% for the former (Code 1271.12 Base Vacant Undifferentiated) and 21% for the latter (Code 1112 Low Density Single Family Residential). subareas A1 through A7, A8-2 ,A9, A10-1 and A10-2 are characterized by Vacant Undifferentiated only. Subarea A8-1 is mixed use and so a weighted percent impervious was determined based on land use type (Table 6). Subarea Lot1b is developed and hence assumed to have a 21% imperviousness.

Table 6. Weighted imperviousness for Subarea A8-1
Area Types Area (ac) Imperviousness
Weighted
Factor
Base Vacant 3.6 1% 1%
Single Family 0.3 21% 3%
Totals: 3.9 3%
The impervious estimates for all subareas are summarized in Table 7.

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14 4.4.6. Summary of subarea characteristics
All of the computed existing subarea characteristics are shown in Table 7 below.

Table 7. Existing condition subarea design data
Subarea
Total
Area
(ac)
Percent
Impervious
Longest
Flow
Path
Length
(ft)
Longest
Flow
Path
Slope
(%)
Routing
Flow Path
Length (ft)
Routing
Flow Path
Slope (%)
Soil
Type
Bulking
factor
DPR
(yd /mi ) DPV (yd³)
A1 5.6 1.0% 971 44% 971 44% 081 2.0 240000 2100
A2 4.8 1.0% 812 47% 812 47% 081 2.0 240000 1800
A3 3.6 1.0% 926 38% 611 26% 081 2.0 240000 1350
A4 7.0 1.0% 749 58% 521 48% 081 2.0 240000 2630
A5 4.7 1.0% 835 32% 757 24% 081 2.0 240000 1760
A6 6.1 1.0% 886 50% 886 50% 081 2.0 240000 2290
A7 5.6 1.0% 983 44% 595 24% 081 2.0 240000 2100
A8-1 3.9 3.0% 1166 23% 806 12% 081 1.921 201000 1220
A8-2 5.1 1.0% 766 38% 659 16% 081 1.964 222000 1770
A9 1.5 1.0% 655 28% 395 20% 081 2.0 240000 560
A10-1 1.7 1.0% 882 13% 617 09% 007 1.604 46000 120
A10-2 1.4 1.0% 768 15% 711 14% 007 1.643 65000 140
Lot1b 0.5 21% 451 24% 184 09% 007 N/A N/A N/A
TOTAL: 51.5 TOTAL: 17840

4.5. Time of concentration calculation
With the subarea parameters identified, Hydrocalc (LACDPW, ND) was used to calculate the times of concentration for each subarea. Both the 25-year (Urban Flood) and the 50-year (Capital Flood) year storms were computed. The detailed output may be found in Appendix C. Hydrocalc computed all times of concentration to be 5 minutes (the minimum allowed) for all existing subareas and both storm events except for subareas A8-1 and A10-2, which were both computed to have 6-minute times of concentration during the 25- year storm (they both had 5-minute times of concentration during the 50-year storm).

4.6. Routing analysis
The existing condition subareas are routed, with drainage flowing from north to south and exiting the site near the intersection of Palm Drive and Grand Avenue. Although there is a storm drain inlet at the outlet, flows and debris during large storm events will typically overwhelm and / or clog the inlet, spill into the street, and flow down the west curb of Grand Avenue.

In addition to the two clear water design storms (the 25-year clear water, 50-year clear water), the capital flood protection requires the 50-year burned flow as well as bulked conditions to be considered. Specifically, the results of the burned flow analyses were used in conjunction with the computed bulking factors to estimate the burned and bulked flows for the 50-year return event (denoted here as Q50 BB). These flows were calculated by multiplying the cumulative bulking factor by the 50-year routed burned flow rates (Q50 Burn). The cumulative bulking factor was required because at several subareas and concentration points, the contributors to the flow had different bulking factors. For example, at A8-1, all three of the upstream subareas (A1, A3 and A5) have bulking factors = 2, whereas at A8-1 the bulking factor is 1.909 (already a weighted value due to different land use and soil types within the subarea). As shown in Table 8, the cumulative bulking factor at A8-1 is therefore 1.981. Likewise, a summary of the cumulative bulking factor calculations at A8-2 , CP1, A10-1, A10-2 and CP2 are summarized in Table 8 through 13, respectively.

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15 Table 8. Cumulative bulking factor at subarea A8-1
Subarea(s) Area (ac) Subarea(s) Bulking factor Cumulative Bulking Factor A8-1 3.9 1.921 0.415
A1,A3,A5 14 2 1.570
Totals: 17.8 1.983
Table 9. Cumulative bulking factor at subarea A8-2
Subarea(s) Area (ac) Subarea(s) Bulking factor Cumulative Bulking Factor A8-2 5.1 1.963 0.893
A6 6.1 2 1.090
Totals: 11.2 1.983
Table 10. Cumulative bulking factor at CP-1
Subarea(s) Area (ac) Subarea(s) Bulking factor Cumulative Bulking Factor A8-1 3.9 1.921 0.251
A8-2 5.1 1.963 0.337
A1,A3,A5,A6 20 2 1.36
Lot1b 0.5 0 0
Totals: 29.4 1.949
Table 11. Cumulative bulking factor at subarea A10-1
Subarea(s) Area (ac) Subarea(s) Bulking factor Cumulative Bulking Factor A10-1 1.7 1.604 0.087
A8-1 3.9 1.921 0.237
A8-2 5.1 1.963 0.318
A1,A3,A5,A6 20 2 1.286
Lot1b 0.5 0 0
Totals: 31.1 1.931
Table 12. Cumulative bulking factor at subarea A10-2
Subarea(s) Area (ac) Subarea(s) Bulking factor Cumulative Bulking Factor A10-2 1.4 1.643 0.115
A2,A4,A7,A9 19 2 1.860
Totals: 20.4 1.975
Table 13. Cumulative bulking factor at subarea CP2
Subarea(s) Area (ac) Subarea(s) Bulking factor Cumulative Bulking Factor A8-2 5.1 1.963 0.193
A8-1 3.9 1.921 0.143
A1,A3,A5,A6 20 2 0.777
Lot1b 0.5 0 0.000
A10-1 1.7 1.604 0.052
A10-2 3.1 1.643 0.045
A2,A4,A7,A9 18.9 2 0.734
Totals: 51.5 1.944
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16 With all of the necessary parameters established, the software program LAR04 (CivilDesign, 2017) was used for the actual routing analysis of the existing conditions. The schematic shown below in Figure 7 describes how the flow through the delineated subareas will progress as well as figure showing a schematic translation between the report existing subarea designations to those used in LAR04. The Existing Condition map in Appendix F also shows the individual routed flows. The LAR04 files are included in Appendix C and the results of the routing analysis are summarized in Table 15. (Note that in addition to the flows, the table also presents the total contributing drainage areas at each location in the model and the cumulative debris volume production (DVP) in yd3.) A table relating existing cumulative areas as designated in the report and the concentration point definitions in LAR04 is also shown below.

The analysis predicts that the overall existing condition routed clear water flow is 142 cfs for the 25-year storm and 160 cfs for the 50-year storm. These values are important because LACDPW requires that the corresponding clear water outflow under the proposed condition be less than those under the existing condition. How the proposed conditions meet this requirement is described in the next section.

Figure 7. Existing condition routing schematic in LAR04.

Table 14. Existing condition cumulative areas at LAR04 concentration points LAR04 Concentration Point Cumulative drainage subareas as shown in report 1A A1
2A A3, A1
3A A5, A3, A1
4A A8-1,A5,A3,A1
5A Lot1b, A8-1,A5,A3,A1
6B A8-2, A6
7B A8-2, A6, A8-1,A5,A3,A1
8AB Lot1b, A8-2, A6, A8-1,A5,A3,A1
9A A10-1, Lot1b, A8-2, A6, A8-1,A5,A3,A1
10D A2
12D A4, A2
12D A7, A4, A2
13D A9, A7, A4, A2
14D A10-2, A9, A7, A4, A2
15AD A10-1, Lot1b, A8-2, A6, A8-1, A5, A3, A1, A10-2, A9, A7, A4, A2 LEGEND
X1 Subarea
Routing (overland)
Concentration Point
1A
2A
6B
12D
13D
10D
3A
11D
8AB
14D
Existing Conditions Routing Progression AS ENTERED INTO LAR04 A1
A3
A5
A6
A10-2
A9
A2
A4
A7
A8-1
Lot1b
4A
15AD
CP1
A10-1 CP2
A8-2
5A
7B
9A
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17 Table 15. Summary of routed flows under the existing condition LAR04 Sub-area / CP Area
(ac)
Σ Area
(ac) Q25 (cfs) ΣQ25(cfs)
Q50
(cfs)
ΣQ50
(cfs)
Q50Burn
(cfs)
ΣQ50Burn
(cfs)
Cum.

Bulk
Fact.

Q50 BB
(cfs)
ΣQ50
BB
(cfs)
DPV
(yd³)
ΣDVP
(yd³)
1A A1 5.6 5.6 21.7 21.7 25.1 25.1 26 26 2 52 52 2100 2100 2A A3 3.6 9.2 14 31.3 16.1 36.6 16.7 38.1 2 33.4 76.2 1350 3450 3A A5 4.7 13.9 18.2 42.1 21 49.5 21.8 51.8 2 43.6 104 1760 5210 4A A8-1 3.9 17.7 13.2 46.9 15.7 55.7 16.3 58.8 1.983 32.3 117 1220 6440 5A Lot1b 0.5 0.5 1.8 47.5 2.1 56.8 2.2 2.2 2 4.4 4.4 N/A N/A 6B A6 6.1 6.1 23.6 23.6 27.4 27.4 28.3 28.3 2 56.6 56.6 2290 2290 7B A8-2 5.1 11.2 19.8 36.3 22.9 42.7 23.7 44.5 1.983 47.0 88.2 1770 4060 8AB CP1 29.5 80.8 96.0 101 1.949 197
9A A10-1 1.7 31.1 5.1 81.4 6 96.6 6.5 102 1.931 12.6 197 120 10610 10D A2 4.8 4.8 18.6 18.6 21.5 21.5 22.3 22.3 2 44.6 44.6 1800 1800 11D A4 7 11.8 27.1 42.8 31.4 49.8 32.5 51.7 2 65 103 2630 4430 12D A7 5.6 17.4 21.7 58.1 25.1 68 26.0 70.8 2 52 142 2100 6530 13D A9 1.5 18.9 5.8 61.3 6.7 71.6 7.0 74.8 2 14.0 150 560 7090 14D A10-2 1.4 20.3 4.8 60.4 5.6 70.7 6.1 74.4 1.975 12.1 147 140 7230 15AD CP2 51.5 51.5 142 167 176 1.944 342 N/A 17840
For LAR04 outputs associated with this table, see the Existing Condition Routing section of Appendix C.

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18 5. Proposed Condition

5.1. Overall approach
The proposed (post-developed) conditions exhibit is shown in Map 2 (Appendix F). Note that subareas B through N are offsite drainage areas that are conveyed into the proposed storm drain system, whereas subareas Q and R denote onsite drainage the flows through the proposed private streets. Flow in the storm drain will be split with a portion conveyed into the public storm drain system. Specifically, the design will divert the Qllowable = 89.6 cfs burned, debulked flow to the public storm drain during the 50-year storm (Capital Flood). The other offsite flows will be conveyed along the historic drainage path by means of a flow return structure. All of the onsite flows will be conveyed by the proposed surface streets along the historical path. Note that, with this design, it is only just outside of the project extents that the onsite and offsite flows will combine.

Drainage under the proposed conditions is affected by the following design elements:

1. Storm drain. A new storm drain will convey only offsite flow through the site.

2. Two elevated inlets. The west and middle debris facilities – (denoted B and C with respective primary drainage areas corresponding to subareas B and C) – will be constructed according to the LACDPW regulations for elevated inlets. Note that LACDPW has given an allowance to Dreamland to build the west basin B as an elevated inlet even though the debris production is slightly above the typically imposed maximum capacity of 4,999 cubic yards. See Appendix E for documentation on this variance.

An inclined tower will be required at B. Note that the flows to elevated inlet C will include not only the outflow from C, but also outflows from two other smaller, graded areas F and H (not debris producing).

3. One debris basin. The debris basin D is located directly northeast of the proposed development with corresponding subarea D.

4. Onsite Best Management Practices (BMP) measures. In all developed areas, BMP measures will be implemented to treat runoff. The City of Glendora has requested control over the implementation of these measures. Accordingly, they will be designed to City of Glendora standards and submitted to them under separate review.

5. Inlets. These structures collect drainage from the graded offsite areas K, L, M and N. Since these subareas are within the developed footprint, the subareas are not debris producing and hence their outflows are considered burned only.

6. Parkway Drain. As noted earlier, outflow under the existing condition is ultimately conveyed south along Grand Avenue. Under proposed conditions, the overall outflow from the site is reduced, and a large portion (near but less than the Qallowable = 89.6 cfs) will be conveyed into the storm drainage system. The remaining flow will need to be returned to its historic path along Grand Avenue. To reduce risk to pedestrians and vehicles, a parkway drain will be constructed. This structure will reduce the concentrated storm drain flow to low depth sheet flow. The exact design of the parkway drain will be done as part of the hydraulic calculations during full design following approval of this Hydrology Report.

Flow to and from the parkway drain will be under positive drainage (i.e. a bubbler system will not be required).

7. Flow split. The split of the storm drain flow into the main storm drain system flow and flow to the return flow structure will be accomplished utilizing standard flow splitting measures implemented within a manhole. It is expected that this can be achieved by installing different size pipes. An orifice on one of the pipes may be required to insure the allowable drainage to the storm drain is not exceeded. A sketch of this configuration is shown in Figure 8 below. Note that the design is simplified by the expected elevation changes downstream of the split, which are of sufficient magnitude that the flows will most likely be supercritical and hence backwater effects should not be an issue. Detailed hydraulic calculations of the flow split will accompany the hydraulic design to be developed following Hydrology Report approval.

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19 Figure 8. Flow split schematic

5.2. Proposed Subareas

5.2.1. Hydrologic parameters
The offsite subareas can be divided into undeveloped and therefore debris producing subareas (B, C, and D), versus subareas that are graded and / or developed and so are not debris producing (subareas F, H, K, L, M, N, Q, and R). These subareas are further divided as needed (e.g. B becomes B1, B2, B3) to ensure that no subarea has a flow path greater than 1,000 feet (an LACDPW regulation). Note that there are no subareas designated E, G, I, J, O, or P – these subareas were designated in earlier design iterations but are no longer used in this final analysis.

The following three hydrologic parameters are common to all of the proposed condition subareas:
• Fire factor: 0.71
• 50-year, 24-hour isohyet: 8.3 inches
• DPA zone: 1 (specific to only the debris producing subareas) The following are relevant details regarding the proposed subareas:
• Subareas B, C, and D are assumed to have 1% imperviousness as specified by the LACDPW standard Code 1271.12 (Base Vacant Undifferentiated).
• Subareas B3, C, and D3 are debris producing but contains some non-debris producing, regraded areas to be made erosion resistant by compacted, seeded soil or other appropriate hydromodification. Hence, in these subareas, only that portion which is debris producing was used to determine debris production.

This information is included in Table 16, below.
• As noted previously, the proposed graded subareas K, L, M, N, F, H are not debris producing. Therefore, the percent impervious for these six subareas is taken to be 2% (Code 1272 Vacant Areas), and bulking factors or debris production rates were not computed for these subareas. • The onsite portion of the development is divided into an upper subarea Q and lower subarea R.

Subarea Q contains mostly soil type 081 (upper Gabriel River USGR-G-1), whereas subarea R contains mostly soil type 007 (Handford gravelly sandy loam). As areas of developed, single family home parcels, Q and R were given a maximum percent impervious of 21% (Code 1112 Low Density Single Family Residential). As part of the onsite development, they are not debris producing and hence bulking factors or debris production rates were not computed for these subareas. • As noted earlier, Lot 1 is already developed as a single-family home parcel and will be left unaltered by the proposed improvements. A portion of lot one drains into the proposed development. This area was denoted as Lot1b for the existing condition analysis. Here it was simply included as a portion of subarea Q.

Item #8. Page 1254
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HYDROLOGY STUDY TENTATIVE TRACT 72413
20 Table 16 summarizes all of the hydrologic parameters for the proposed condition subareas.

Table 16. Proposed condition hydrologic design data and debris production of offsite subareas Subarea
Total
area
(ac)
Debris
producing
area (ac)
Impervious
(%)
Longest
flow path
length
(ft)
Longest
flow path
slope
(%)
Routing
flow
path
length
(ft)
Routing
flow
path
slope
(%)
Soil
Type
Bulking
factor
Debris
production
volume
(yd³)
B1 5.6 5.6 1.0% 971 44% 971 44% 081 2.0 2100
B2 3.6 3.6 1.0% 926 38% 605 26% 081 2.0 1350
B3 4.8 4.3 1.0% 660 38% 539 31% 081 2.0 1610
C 6.6 6.0 1.0% 908 48% 908 51% 081 2.0 2250
D1 4.8 4.8 1.0% 812 47% 812 47% 081 2.0 1800
D2 7.0 7.0 1.0% 749 58% 521 48% 081 2.0 2630
D3 6.2 4.9 1.0% 822 53% 431 32% 081 2.0 1850
F 0.9 0 1.0% 540 32% 451 39% 081 N/A N/A
H 1.5 0 1.0% 758 26% 473 42% 081 N/A N/A
K 0.7 0 2.0% 237 21% 194 25% 081 N/A N/A
L 0.7 0 2.0% 224 20% 135 33% 081 N/A N/A
M 0.7 0 2.0% 310 14% 157 27% 081 N/A N/A
N 0.5 0 2.0% 170 31% 135 40% 081 N/A N/A
Q 5.5 0 21% 898 18% 898 18% 081 N/A N/A
R 4.0 0 21% 750 08% 679 09% 007 N/A N/A
TOTAL: 53.1 TOTAL: 13,590

5.2.2. Time of concentration calculation
Hydrocalc (ND) was used to calculate the 25-year and 50-year return storm times of concentration. Consistent with the time of concentration analysis of the existing condition, almost all of the proposed subarea times of concentration defaulted to 5 minutes. This is likely a result of the small drainage areas and steep slopes. The one exception is for R, which has a 6-minute time of concentration during the 25-year storm. The detailed Hydrocalc output may be found in Appendix C.

5.2.3. Routing analysis
The delineated proposed subareas were analyzed for the 25-year (Urban Flood) and 50-year (Capital Flood). As can be seen in the proposed condition routing schematic (Figure 9, below), this modeling effort was divided into four separate analyses with LAR04 and three separate detention analyses with Retard, as follows:

1. Subareas B1, B2, and B3 were routed in LAR04 as shown in Figure 9 to obtain an input hydrograph to Elevated Inlet B. Details of this analysis can be found in Appendix C here: SUBAREA B ROUTING ANALYSIS.

2. Subareas C, F, and H were combined in LAR04 as shown in Figure 9 to obtain an input hydrograph to Elevated Inlet C. Details of this analysis can be found in Appendix C here: SUBAREAS C F AND H ROUTING ANALYSIS.

3. Subareas D1, D2, and D3 were routed in LAR04 as shown in Figure 9 to obtain an input hydrograph to Debris Basin D. Details of this analysis can be found in Appendix C here: SUBAREA D ROUTING ANALYSIS.

4. Three separate detention analyses were conducted for Elevated Inlet B, Elevated Inlet C, and Debris Basin D using the program Retard and the hydrographs developed from steps 1 through 3. Note that outflow from these facilities into the storm drain will result from a combination of flow into the perforated intake and flow over the debris barrier should water levels rise high enough to do so. The perforated intake structure was modeled as a sharp-crested, free falling weir with coefficient of 3.0 and a total width of 3 feet (in keeping with the required 18 4-inch perforations, and constricted 50% to account for end losses), with an invert elevation assumed to be at the base elevation of the detention.

Overflow from the debris barriers was also modeled as part of the analysis, each assumed to be a 10- Item #8. Page 1255
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21 foot long, sharp-crested weir with a coefficient of 3.0 (note that the overall length of the debris barriers will be more than this at the different installation, but only a 10 feet width of them will be set at the given design elevation – the remainder will be set at the high water elevation). Stage storage curves were developed using the incremental volume method and assuming the debris containment facility was at capacity prior to flow initiation. (See section 6. “Debris protection measures” for development of the debris elevations and stage storage curves.) The output from the detention analyses can be found in Appendix C here: DETENTION ANALYSIS. The clear water routing results are summarized in Table 17 (Urban Flood) and Table 18 (Capital Flood) below. Note that, in keeping with LACDPW regulations, a minimum 2 feet of freeboard is maintained in all three basins for both storm events.

5. A final LAR04 routing of the proposed condition outflow was conducted as a single analysis as follows:
a. The outflow hydrographs from the detention analyses were used as inputs for the storm drain analysis. Also, as noted in Figure 9, offsite subareas K, L, M, and N contribute inflow hydrographs to the storm drain system. These hydrographs were routed together and their combined flows analyzed through the storm drain system all the way to the flow split. b. Onsite subareas Q and R were routed through the proposed streets to the intersection of Grand Avenue and W. Palm Drive as shown in Figure 9. Appendix D contains the hydraulic calculations that verify the proposed onsite street cross-sections have sufficient carrying capacity for this flow, and Appendix B includes a copy of a letter issued by the City of Glendora approving this approach to onsite flow conveyance.
c. The overall output hydrograph from Step 5a was combined with the output hydrograph from Step 5b to obtain an overall peak flow at the property line. Note that the water from these two sources doesn’t actually combine at the property line (they combine slightly downgradient of the property line), but this step was necessary within the program to obtain an overall estimate of peak flow from the site as needed to verify that the proposed outflow does not exceed existing flow.

Table 17. Detention analysis results: 25-year storm (Urban Flood) Debris
structure
Debris elev. at the
debris barriers
Crest
elev.

Debris
barrier elev.

Peak inflow
(cfs)
Peak outflow
(cfs)
High water
surface elev.

Freeboard
(feet)
B 1122.0 1128.0 1126.0 44.6 34.1 1124.4 3.6
C 1092.0 1096.0 1093.5 34.9 26.9 1093.7 2.3
D 1121.0 1125.5 1122.5 62.2 53.2 1123.3 2.2
Table 18. Detention analysis results: 50-year storm (Capital Flood) Debris
structure
Debris elev. at the
debris barriers
Crest
elev.

Debris
barrier elev.

Peak inflow
(cfs)
Peak outflow
(cfs)
High water
surface elev.

Freeboard
(feet)
B 1122.0 1128.0 1126.0 52.4 39.6 1124.7 3.3
C 1092.0 1096.0 1093.5 40.4 31.4 1093.8 2.2
D 1121.0 1125.5 1122.5 72.4 62.8 1123.5 2.0
Table 19. Detention analysis results: 50-year storm (Capital Flood Burned Flows) Debris
structure
Debris elev. at the
debris barriers
Crest
elev.

Debris
barrier elev.

Peak inflow
(cfs)
Peak outflow
(cfs)
High water
surface elev.

Freeboard
(feet)
B 1122.0 1128.0 1126.0 54.7 41.5 1124.8 3.2
C 1092.0 1096.0 1093.5 41.8 32.8 1093.9 2.1
D 1121.0 1125.5 1122.5 75.3 65.4 1123.5 2.0
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HYDROLOGY STUDY TENTATIVE TRACT 72413
22 A schematic of the proposed condition outflow routing in shown below.

Figure 9. Proposed condition outflow routing schematic for LAR04.

K L M
N
Parkway Drain
Flow
Split
Connect to existing storm drain
Overland flow
(Grand Ave. valley gutter)
LEGEND
X1 Subarea
Routing (overland)
Routing (storm drain)
Concentration point
Flow split (diversion)
Parkway drain
Existing storm drain
Q
R
Overland flow
to Palm Drive
Project Property Line
Outflow
Hydrograph
from
elevated inlet B
12F
Project Property Line
Outflow
hydrograph
from elevated
inlet C
Outflow
hydrograph
from debris
basin D
13F
8AC
11AE
1A
3AB
2B
7CD
4C
6D
5D
10E
9E
14AF

AS MAPPED
AS ENTERED IN LAR04
CP1
CP3
CP2
CP4
CP7
CP6
CP5
CP8
Flow Split
B1
B2
B3
Elevated Inlet B
Elevated Inlet C
C
H F
D1
D2
D3
Debris Basin D
1A
3A
2A
1A
3A
2A 2A
1A
3A
LAR04 Model of Subarea B LAR04 Model of Subarea C
LAR04 Model of Subarea D
LAR04 Proposed
Conditions Model
Item #8. Page 1257
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HYDROLOGY STUDY TENTATIVE TRACT 72413
23 The following tables list the contributing subareas to each LAR04 concentration point for the various models.

The results of the routing analysis are summarized in Table 24. Details of the LAR04 analysis can be found in Appendix C here: PROPOSED CONDITIONS OUTFLOW ROUTING ANALYSIS.

Table 20. LAR04 Model B, Proposed condition subareas B1 – B3 cumulative areas at LAR04 concentration points LAR04 Concentration Point Cumulative drainage subareas as shown in report 1A B1
2A B2, B1
3A B3, B2, B1
Table 21. LAR04 Model C, Proposed condition subareas C, F, and H cumulative areas at LAR04 concentration points
LAR04 Concentration Point Cumulative drainage subareas as shown in report 1A C
2A F, C
3A H, F, C
Table 22. LAR04 Model D, Proposed conditions subareas D1 – D3 cumulative areas at LAR04 concentration points
LAR04 Concentration Point Cumulative drainage subareas as shown in report 1A D1
2A D2, D1
3A D3, D2, D1
Table 23. Proposed condition cumulative areas at LAR04 concentration points LAR04 Concentration Point Cumulative drainage subareas as shown in report 1A B1, B2, B3
2B K
3AB K, B1, B2, B3
4C C, F, H
5D M
6D L, M
7CD C, F, H, L, M
8AC K, B1, B2, B3, C, F, H, L, M
9E D1, D2, D3
10E N, D1, D2, D3
11AE K, B1, B2, B3, C, F, H, L, M, N, D1, D2, D3
12F Q
13F R, Q
14AF K, B1, B2, B3, C, F, H, L, M, N, D1, D2, D3, R, Q
Item #8. Page 1258
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HYDROLOGY STUDY TENTATIVE TRACT 72413
24 Table 24. Proposed conditions routing analysis summary LAR04
Model,
Node
Subarea /
CP
Area
(ac)
ΣArea
(ac)
Q25
(cfs)
ΣQ25
(cfs)
Q50
(cfs)
ΣQ50
(cfs)
Q50
Burn
(cfs)
ΣQ50
Burn
(cfs)
Cum
Bulk
Fact
Q50
BB
(cfs)
ΣQ50
BB
(cfs)
DPV
(yd³)
ΣDVP
(yd³)
B, 1A B1 5.6 5.6 21.6 22.6 25.1 25.1 26 26 2.0 52 52 2100 2100 B, 2A B2 3.6 9.2 14 31.3 16.1 36.6 16.7 38.1 2.0 33.4 76.2 1350 3450 B, 3A B3 4.8 14 18.6 44.6 21.5 52.4 22.9 54.7 2.0 45.8 110 1760 5060 C, 1A C 6.6 6.6 25.6 25.6 29.6 29.6 30.7 30.7 2.0 61.4 2250 2250 C, 2A F 0.9 7.5 3.5 29.1 4.0 33.7 4.2 34.8 N/A N/A N/A N/A N/A C, 3A H 1.5 9.0 5.8 34.9 6.7 40.4 7.0 41.8 N/A N/A N/A N/A N/A D, 1A D1 4.8 4.8 18.6 18.6 21.5 21.5 22.3 22.3 2.0 44.6 44.6 1800 1800 D, 2A D2 7.0 11.8 27.2 42.8 31.4 49.8 32.5 51.7 2.0 65 103 2630 4430 D, 3A D3 6.2 18 24 62.2 27.8 72.4 28.8 75.3 2.0 57.6 151 1850 6280 1A CP1 14 34.1 39.6 42
4B K 0.7 14.7 2.7 2.7 3.1 3.1 3.3 3.3 N/A N/A N/A N/A N/A 3AB CP4 0.7 14.7 35.4 41.1 43.5
4C CP2 9.0 26.9 31.4 32.8
5D M 0.7 0.7 2.7 2.7 3.1 3.1 3.3 3.3 N/A N/A N/A N/A N/A 6D L 0.7 1.4 2.7 5.1 5.8 5.9 3.2 6.2 N/A N/A N/A N/A N/A 7CD CP5 10.4 31.8 37.1 38.7
8AC CP6 25.1 64.7 75.4 79.0
9E CP3 18 53.3 62.8 65.8
10E N 0.5 18.5 1.9 54.4 2.2 64.3 2.3 67.3 N/A N/A N/A N/A N/A 11AE CP7 43.6 118 138 145
12F Q 5.5 5.5 21.4 19.2 22.2 22.2 22.9 22.9 N/A N/A N/A N/A N/A 13F R 4.0 9.5 31.2 29.4 34.5 34.5 15.6 36.1 N/A N/A N/A N/A N/A 14AF 53.1 142 167 175 N/A N/A N/A
The corresponding LAR04 hyperlinks for this table are as follows:
• Proposed Condition Subarea B Routing in LAR04
• Proposed Condition Subareas C, F, and H Routing in LAR04 • Proposed Condition Subarea D Routing in LAR04
• Proposed Condition Outflow Routing in LAR04

5.3. Comparison of existing condition versus proposed condition peak flows Table 25 shows all of the flows for the existing and proposed condition at the property line for the clear and burned 25-year (Urban Flood) and 50-year (Capital Flood) storm events. For all storms, the total postdevelopment outflow is seen to be less than or equivalent to that under the existing condition.

Table 25. Comparison of outflows
Storm Event
Proposed
Condition Onsite
Street Flow (cfs)
Proposed
Condition Onsite
Storm Drain Flow*
(cfs)
Proposed Condition
Total Combined Flow
(cfs)
Existing Condition
Routed Clear Water
Flow (cfs)
25-year Clear (Urban Flood) 29.4 118 142 142
50-year Clear (Capital Flood) 34.5 138 167 167
50-year Burned (Capital Flood) 36.4 145 175 176
* The onsite storm drain flow at the property is split into flow into the existing storm drain and the flow to the return flow structure.

Item #8. Page 1259
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HYDROLOGY STUDY TENTATIVE TRACT 72413
25 As noted previously in this report, the total burned outflow to the existing storm drain is limited to 89.6 cfs.

During the 50-year, burned conditions storm, this will require the proposed flow split to convey the 89.6 cfs to the storm drain system and return the remaining flow (145 cfs – 89.6 cfs = 54.9 cfs) to the street near its historic outflow location.

Although the installed flow split system will be designed for burned flow conditions, it will also reduce the clear water flow to the storm drain for all other storm events as well. The hydraulics of the flow diversion is beyond the scope of this Hydrology Report and will be analyzed at the design stage, but here a reasonable assumption is that the split for other storm types and return periods will maintain the same ratio as developed for the burned flow split. That is, the ratio of the allowable flow (89.6 cfs) to the total 50-year burned flow at the split (145 cfs) will remain constant at a value of 89.6 cfs / 145 cfs = 0.62. With this assumption, the relevant storm drain and street outflow calculations can be made (Table 26).

Table 26. Estimates of design outflows to the public storm drain Storm Event
Total Storm Drain Flow
at Split (cfs)
Portion of Storm Drain
Outflow Draining to
Public Storm Drain (cfs)
Portion of Storm Drain Outflow
Draining to Parkway Drain (cfs)
25-year Clear (Urban Flood) 118 73.2 44.9
50-year Clear (Capital Flood) 138 85.5 52.4
50-year Burn (Capital Flood) 145 89.6 54.9
Ultimate condition Q50 burned offsite + Q25 clearwater onsite = 145 + 29 = 174 cfs Item #8. Page 1260
Meeting Date: 1/24/2023 / Packet Page #: 1325
HYDROLOGY STUDY TENTATIVE TRACT 72413
26 6. Debris protection measures

6.1. Debris containment design
As noted earlier, debris containment will be provided by elevated inlets B and C and the debris basin D. All design and construction will be consistent with the LACDPW Sedimentation Manual (LACDPW, 2006). A schematic of each debris containment facility showing the incremental volume calculations for the debris storage as well as the stage storage relationship used for the B, C, and D storm water detention analysis is provided in figures 10, 11, and 12, respectively. The schematics indicate that volume (whether for debris containment estimates or hydraulic stage storage) is determined by the product of the contour elevation differences and the average contour areas immediately below and above any point of interest. Note that the summation of the debris basin incremental volumes matches the overall capacity estimates shown in Table 27 and the detention routing calculations shown in Appendix C.

Figure 10. Elevated Inlet B Profile Schematic (not to scale) Figure 11. Elevated Inlet C Profile Schematic (not to scale) Item #8. Page 1261
Meeting Date: 1/24/2023 / Packet Page #: 1326
HYDROLOGY STUDY TENTATIVE TRACT 72413
27 Figure 12. Debris Basin D Profile Schematic (not to scale) Table 27. Debris containment details
Debris
Protection
Installation
Contributing
Subareas
Debris Protection
Type
Debris
Production
(cubic yards)
Debris Capacity
(cubic yards)
B B1, B2, B3 Elevated inlet 5060 5080
C C Elevated inlet 2250 2300
D D1, D2, D3 Debris basin 6280 6300
As shown by the computations presented in the schematics, all debris containment facility capacities exceed requirements.

Finally, two other aspects of the debris containment facilities must be noted:

1. The steep slopes of the debris containment installations will be protected according to the site geotechnical report by G.A. Nicoll and Associates (G. A. Nicoll and Assocociates Inc., 2016)

2. All proposed debris protection measures will be transferred to Los Angeles County for maintenance and future evaluation.

Item #8. Page 1262
Meeting Date: 1/24/2023 / Packet Page #: 1327
HYDROLOGY STUDY TENTATIVE TRACT 72413
28 7. Conclusion
The narrative, calculations, figures, tables, and maps in this study provide a comprehensive plan to protect the proposed subdivision from flooding and debris both from onsite and offsite sources. As a further benefit, homes downslope of the proposed development which are currently at risk will be protected from debris inundation for the first time in years, possibly decades.

Despite the steep terrain, the proposed debris mitigation measures will be easy to access by County personnel, with a dedicated low sloping access road that includes fully realized storm water controls and large turnaround areas.

Given the importance of this project with regards to protecting existing and future homeowners, and in recognition of the complicated nature of many of the required design elements and hydrologic analysis, all known LACDPW standards, including the hydrology plan checklist items, have been proactively addressed herein. This effort was made to honor the critical role that the LACDPW has historically played in the project as well as in anticipation that the Dreamland design team and LACDPW will continue to work together to efficiently develop the Silent Ranch subdivision to the benefit of both new homeowners and the existing community.

Item #8. Page 1263
Meeting Date: 1/24/2023 / Packet Page #: 1328
HYDROLOGY STUDY TENTATIVE TRACT 72413
29 8. References
CivilDesign. (2017). LAR04: Modified Rational Method, F0601, Los Angeles Co., Version 11. San Bernardino, CA:

CivilDesign. Retrieved 4 14, 2016, from CivilDesign: https://civildesign.com/products/lar04-modifiedrational-method-f0601-los-angeles-co G. A. Nicoll and Assocociates Inc. (2016). Preliminary Report of Geotechnical Investigation , Proposed Debris Basins , Dams and Access Roads. Glendora, CA.

LACDPW. (2006). Hydrology Manual. Alhambra: LCDPW Water Resources Division.

LACDPW. (2006). Sedimentation Manual. Alhambra: LACDPW Water Resources Division.

LACDPW. (2014). Low Impact Development Standards Manual. Alhambra: LACDPW.

LACDPW. (ND). HydroCalc Version 1.0.2. Los Angeles, CA: LACDPW. Retrieved 4 14, 2016, from https://dpw.lacounty.gov/wmd/dsp_LowImpactDevelopment.cfm Item #8. Page 1264
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HYDROLOGY STUDY TENTATIVE TRACT 72413
A-1
Appendix A. Allowable Outflow
Item #8. Page 1265
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HYDROLOGY STUDY TENTATIVE TRACT 72413
A-2
Item #8. Page 1266
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HYDROLOGY STUDY TENTATIVE TRACT 72413
B-1
Appendix B. City of Glendora Onsite Flow Approval
Item #8. Page 1267
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HYDROLOGY STUDY TENTATIVE TRACT 72413
B-2
Item #8. Page 1268
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HYDROLOGY STUDY TENTATIVE TRACT 72413
C-1
Appendix C. Hydrologic Calculations
Item #8. Page 1269
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HYDROLOGY STUDY TENTATIVE TRACT 72413
C-2
The Hydrocalc output shown in this Appendix corresponds exactly to the labels provided in this report.

Unfortunately, the LAR04 software does not allow the user to change the default labeling. Hence, a translation from the labels provided in the report to what was used in LAR04 has been provided for clarity. To that end, each LAR04 output on the following pages has a title sheet showing a table relating the subarea designations with the points of concentration analyzed by LAR04, as well as a figure showing the schematic in the report and its translation into LAR04.

Item #8. Page 1270
Meeting Date: 1/24/2023 / Packet Page #: 1335
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-3
Hydrocalc: 25-Year Storm (Urban Flood)
Note that the Hydrocalc output on the following pages was used to calculate time of concentration ONLY. The flows shown were not used because routing via LAR04 was used instead (output shown later in this appendix).

Item #8. Page 1271
Meeting Date: 1/24/2023 / Packet Page #: 1336
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/25year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID A1
Area (ac) 5.6
Flow Path Length (ft) 971.0
Flow Path Slope (vft/hft) 0.44
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.01
Soil Type 81
Design Storm Frequency 25-yr
Fire Factor 0.71
LID False
Output Results
Modeled (25-yr) Rainfall Depth (in) 7.2874
Peak Intensity (in/hr) 4.3479
Undeveloped Runoff Coefficient (Cu) 0.8747
Developed Runoff Coefficient (Cd) 0.875
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 21.3035
Burned Peak Flow Rate (cfs) 22.2055
24-Hr Clear Runoff Volume (ac-ft) 0.8929
24-Hr Clear Runoff Volume (cu-ft) 38896.3538
C-4
Item #8. Page 1272
Meeting Date: 1/24/2023 / Packet Page #: 1337
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/25year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID A2
Area (ac) 4.8
Flow Path Length (ft) 812.0
Flow Path Slope (vft/hft) 0.47
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.01
Soil Type 81
Design Storm Frequency 25-yr
Fire Factor 0.71
LID False
Output Results
Modeled (25-yr) Rainfall Depth (in) 7.2874
Peak Intensity (in/hr) 4.3479
Undeveloped Runoff Coefficient (Cu) 0.8747
Developed Runoff Coefficient (Cd) 0.875
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 18.2602
Burned Peak Flow Rate (cfs) 19.0332
24-Hr Clear Runoff Volume (ac-ft) 0.7654
24-Hr Clear Runoff Volume (cu-ft) 33339.7318
C-5
Item #8. Page 1273
Meeting Date: 1/24/2023 / Packet Page #: 1338
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/25year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID A3
Area (ac) 3.6
Flow Path Length (ft) 926.0
Flow Path Slope (vft/hft) 0.38
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.01
Soil Type 81
Design Storm Frequency 25-yr
Fire Factor 0.71
LID False
Output Results
Modeled (25-yr) Rainfall Depth (in) 7.2874
Peak Intensity (in/hr) 4.3479
Undeveloped Runoff Coefficient (Cu) 0.8747
Developed Runoff Coefficient (Cd) 0.875
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 13.6951
Burned Peak Flow Rate (cfs) 14.2749
24-Hr Clear Runoff Volume (ac-ft) 0.574
24-Hr Clear Runoff Volume (cu-ft) 25004.7989
C-6
Item #8. Page 1274
Meeting Date: 1/24/2023 / Packet Page #: 1339
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/25year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID A4
Area (ac) 7.0
Flow Path Length (ft) 749.0
Flow Path Slope (vft/hft) 0.58
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.01
Soil Type 81
Design Storm Frequency 25-yr
Fire Factor 0.71
LID False
Output Results
Modeled (25-yr) Rainfall Depth (in) 7.2874
Peak Intensity (in/hr) 4.3479
Undeveloped Runoff Coefficient (Cu) 0.8747
Developed Runoff Coefficient (Cd) 0.875
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 26.6294
Burned Peak Flow Rate (cfs) 27.7568
24-Hr Clear Runoff Volume (ac-ft) 1.1162
24-Hr Clear Runoff Volume (cu-ft) 48620.4423
C-7
Item #8. Page 1275
Meeting Date: 1/24/2023 / Packet Page #: 1340
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/25year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72412
Subarea ID A5
Area (ac) 4.7
Flow Path Length (ft) 835.0
Flow Path Slope (vft/hft) 0.32
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.01
Soil Type 81
Design Storm Frequency 25-yr
Fire Factor 0.71
LID False
Output Results
Modeled (25-yr) Rainfall Depth (in) 7.2874
Peak Intensity (in/hr) 4.3479
Undeveloped Runoff Coefficient (Cu) 0.8747
Developed Runoff Coefficient (Cd) 0.875
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 17.8798
Burned Peak Flow Rate (cfs) 18.6367
24-Hr Clear Runoff Volume (ac-ft) 0.7494
24-Hr Clear Runoff Volume (cu-ft) 32645.1541
C-8
Item #8. Page 1276
Meeting Date: 1/24/2023 / Packet Page #: 1341
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/25year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID A6
Area (ac) 6.1
Flow Path Length (ft) 886.0
Flow Path Slope (vft/hft) 0.5
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.01
Soil Type 81
Design Storm Frequency 25-yr
Fire Factor 0.71
LID False
Output Results
Modeled (25-yr) Rainfall Depth (in) 7.2874
Peak Intensity (in/hr) 4.3479
Undeveloped Runoff Coefficient (Cu) 0.8747
Developed Runoff Coefficient (Cd) 0.875
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 23.2056
Burned Peak Flow Rate (cfs) 24.1881
24-Hr Clear Runoff Volume (ac-ft) 0.9727
24-Hr Clear Runoff Volume (cu-ft) 42369.2425
C-9
Item #8. Page 1277
Meeting Date: 1/24/2023 / Packet Page #: 1342
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/25year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID A7
Area (ac) 5.6
Flow Path Length (ft) 983.0
Flow Path Slope (vft/hft) 0.44
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.01
Soil Type 81
Design Storm Frequency 25-yr
Fire Factor 0.71
LID False
Output Results
Modeled (25-yr) Rainfall Depth (in) 7.2874
Peak Intensity (in/hr) 4.3479
Undeveloped Runoff Coefficient (Cu) 0.8747
Developed Runoff Coefficient (Cd) 0.875
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 21.3035
Burned Peak Flow Rate (cfs) 22.2055
24-Hr Clear Runoff Volume (ac-ft) 0.8929
24-Hr Clear Runoff Volume (cu-ft) 38896.3538
C-10
Item #8. Page 1278
Meeting Date: 1/24/2023 / Packet Page #: 1343
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/25year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID A8-1
Area (ac) 3.9
Flow Path Length (ft) 1166.0
Flow Path Slope (vft/hft) 0.23
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.03
Soil Type 81
Design Storm Frequency 25-yr
Fire Factor 0.71
LID False
Output Results
Modeled (25-yr) Rainfall Depth (in) 7.2874
Peak Intensity (in/hr) 3.9908
Undeveloped Runoff Coefficient (Cu) 0.8664
Developed Runoff Coefficient (Cd) 0.8674
Time of Concentration (min) 6.0
Clear Peak Flow Rate (cfs) 13.5
Burned Peak Flow Rate (cfs) 14.104
24-Hr Clear Runoff Volume (ac-ft) 0.6518
24-Hr Clear Runoff Volume (cu-ft) 28393.9124
C-11
Item #8. Page 1279
Meeting Date: 1/24/2023 / Packet Page #: 1344
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/25year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72414
Subarea ID A8-2
Area (ac) 5.1
Flow Path Length (ft) 766.0
Flow Path Slope (vft/hft) 0.38
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.01
Soil Type 81
Design Storm Frequency 25-yr
Fire Factor 0.71
LID False
Output Results
Modeled (25-yr) Rainfall Depth (in) 7.2874
Peak Intensity (in/hr) 4.3479
Undeveloped Runoff Coefficient (Cu) 0.8747
Developed Runoff Coefficient (Cd) 0.875
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 19.4014
Burned Peak Flow Rate (cfs) 20.2228
24-Hr Clear Runoff Volume (ac-ft) 0.8132
24-Hr Clear Runoff Volume (cu-ft) 35423.4651
C-12
Item #8. Page 1280
Meeting Date: 1/24/2023 / Packet Page #: 1345
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/25year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID A9
Area (ac) 1.5
Flow Path Length (ft) 655.0
Flow Path Slope (vft/hft) 0.28
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.01
Soil Type 81
Design Storm Frequency 25-yr
Fire Factor 0.71
LID False
Output Results
Modeled (25-yr) Rainfall Depth (in) 7.2874
Peak Intensity (in/hr) 4.3479
Undeveloped Runoff Coefficient (Cu) 0.8747
Developed Runoff Coefficient (Cd) 0.875
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 5.7063
Burned Peak Flow Rate (cfs) 5.9479
24-Hr Clear Runoff Volume (ac-ft) 0.2392
24-Hr Clear Runoff Volume (cu-ft) 10418.6662
C-13
Item #8. Page 1281
Meeting Date: 1/24/2023 / Packet Page #: 1346
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/25year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID A10-1
Area (ac) 1.7
Flow Path Length (ft) 882.0
Flow Path Slope (vft/hft) 0.13
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.01
Soil Type 7
Design Storm Frequency 25-yr
Fire Factor 0.71
LID False
Output Results
Modeled (25-yr) Rainfall Depth (in) 7.2874
Peak Intensity (in/hr) 3.9908
Undeveloped Runoff Coefficient (Cu) 0.7451
Developed Runoff Coefficient (Cd) 0.7467
Time of Concentration (min) 6.0
Clear Peak Flow Rate (cfs) 5.0656
Burned Peak Flow Rate (cfs) 5.5685
24-Hr Clear Runoff Volume (ac-ft) 0.1711
24-Hr Clear Runoff Volume (cu-ft) 7455.0408
C-14
Item #8. Page 1282
Meeting Date: 1/24/2023 / Packet Page #: 1347
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/25year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID A10-2
Area (ac) 1.4
Flow Path Length (ft) 768.0
Flow Path Slope (vft/hft) 0.15
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.01
Soil Type 7
Design Storm Frequency 25-yr
Fire Factor 0.71
LID False
Output Results
Modeled (25-yr) Rainfall Depth (in) 7.2874
Peak Intensity (in/hr) 4.3479
Undeveloped Runoff Coefficient (Cu) 0.7653
Developed Runoff Coefficient (Cd) 0.7667
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 4.6666
Burned Peak Flow Rate (cfs) 5.0874
24-Hr Clear Runoff Volume (ac-ft) 0.1412
24-Hr Clear Runoff Volume (cu-ft) 6151.6862
C-15
Item #8. Page 1283
Meeting Date: 1/24/2023 / Packet Page #: 1348
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/25year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID B1
Area (ac) 5.6
Flow Path Length (ft) 971.0
Flow Path Slope (vft/hft) 0.44
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.01
Soil Type 81
Design Storm Frequency 25-yr
Fire Factor 0.71
LID False
Output Results
Modeled (25-yr) Rainfall Depth (in) 7.2874
Peak Intensity (in/hr) 4.3479
Undeveloped Runoff Coefficient (Cu) 0.8747
Developed Runoff Coefficient (Cd) 0.875
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 21.3035
Burned Peak Flow Rate (cfs) 22.2055
24-Hr Clear Runoff Volume (ac-ft) 0.8929
24-Hr Clear Runoff Volume (cu-ft) 38896.3538
C-16
Item #8. Page 1284
Meeting Date: 1/24/2023 / Packet Page #: 1349
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/25year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID B2
Area (ac) 3.6
Flow Path Length (ft) 926.0
Flow Path Slope (vft/hft) 0.38
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.01
Soil Type 81
Design Storm Frequency 25-yr
Fire Factor 0.71
LID False
Output Results
Modeled (25-yr) Rainfall Depth (in) 7.2874
Peak Intensity (in/hr) 4.3479
Undeveloped Runoff Coefficient (Cu) 0.8747
Developed Runoff Coefficient (Cd) 0.875
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 13.6951
Burned Peak Flow Rate (cfs) 14.2749
24-Hr Clear Runoff Volume (ac-ft) 0.574
24-Hr Clear Runoff Volume (cu-ft) 25004.7989
C-17
Item #8. Page 1285
Meeting Date: 1/24/2023 / Packet Page #: 1350
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/25year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID B3
Area (ac) 4.8
Flow Path Length (ft) 660.0
Flow Path Slope (vft/hft) 0.38
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.01
Soil Type 81
Design Storm Frequency 25-yr
Fire Factor 0.71
LID False
Output Results
Modeled (25-yr) Rainfall Depth (in) 7.2874
Peak Intensity (in/hr) 4.3479
Undeveloped Runoff Coefficient (Cu) 0.8747
Developed Runoff Coefficient (Cd) 0.875
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 18.2602
Burned Peak Flow Rate (cfs) 19.0332
24-Hr Clear Runoff Volume (ac-ft) 0.7654
24-Hr Clear Runoff Volume (cu-ft) 33339.7318
C-18
Item #8. Page 1286
Meeting Date: 1/24/2023 / Packet Page #: 1351
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/25year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID C
Area (ac) 6.6
Flow Path Length (ft) 908.0
Flow Path Slope (vft/hft) 0.48
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.01
Soil Type 81
Design Storm Frequency 25-yr
Fire Factor 0.71
LID False
Output Results
Modeled (25-yr) Rainfall Depth (in) 7.2874
Peak Intensity (in/hr) 4.3479
Undeveloped Runoff Coefficient (Cu) 0.8747
Developed Runoff Coefficient (Cd) 0.875
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 25.1077
Burned Peak Flow Rate (cfs) 26.1707
24-Hr Clear Runoff Volume (ac-ft) 1.0524
24-Hr Clear Runoff Volume (cu-ft) 45842.1313
C-19
Item #8. Page 1287
Meeting Date: 1/24/2023 / Packet Page #: 1352
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/25year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID D1
Area (ac) 4.8
Flow Path Length (ft) 812.0
Flow Path Slope (vft/hft) 0.47
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.01
Soil Type 81
Design Storm Frequency 25-yr
Fire Factor 0.71
LID False
Output Results
Modeled (25-yr) Rainfall Depth (in) 7.2874
Peak Intensity (in/hr) 4.3479
Undeveloped Runoff Coefficient (Cu) 0.8747
Developed Runoff Coefficient (Cd) 0.875
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 18.2602
Burned Peak Flow Rate (cfs) 19.0332
24-Hr Clear Runoff Volume (ac-ft) 0.7654
24-Hr Clear Runoff Volume (cu-ft) 33339.7318
C-20
Item #8. Page 1288
Meeting Date: 1/24/2023 / Packet Page #: 1353
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/25year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID D2
Area (ac) 7.0
Flow Path Length (ft) 749.0
Flow Path Slope (vft/hft) 0.58
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.01
Soil Type 81
Design Storm Frequency 25-yr
Fire Factor 0.71
LID False
Output Results
Modeled (25-yr) Rainfall Depth (in) 7.2874
Peak Intensity (in/hr) 4.3479
Undeveloped Runoff Coefficient (Cu) 0.8747
Developed Runoff Coefficient (Cd) 0.875
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 26.6294
Burned Peak Flow Rate (cfs) 27.7568
24-Hr Clear Runoff Volume (ac-ft) 1.1162
24-Hr Clear Runoff Volume (cu-ft) 48620.4423
C-21
Item #8. Page 1289
Meeting Date: 1/24/2023 / Packet Page #: 1354
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/25year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID D3
Area (ac) 6.2
Flow Path Length (ft) 822.0
Flow Path Slope (vft/hft) 0.53
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.01
Soil Type 81
Design Storm Frequency 25-yr
Fire Factor 0.71
LID False
Output Results
Modeled (25-yr) Rainfall Depth (in) 7.2874
Peak Intensity (in/hr) 4.3479
Undeveloped Runoff Coefficient (Cu) 0.8747
Developed Runoff Coefficient (Cd) 0.875
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 23.5861
Burned Peak Flow Rate (cfs) 24.5846
24-Hr Clear Runoff Volume (ac-ft) 0.9886
24-Hr Clear Runoff Volume (cu-ft) 43063.8203
C-22
Item #8. Page 1290
Meeting Date: 1/24/2023 / Packet Page #: 1355
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/25year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID F
Area (ac) 0.9
Flow Path Length (ft) 540.0
Flow Path Slope (vft/hft) 0.32
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.02
Soil Type 81
Design Storm Frequency 25-yr
Fire Factor 0.71
LID False
Output Results
Modeled (25-yr) Rainfall Depth (in) 7.2874
Peak Intensity (in/hr) 4.3479
Undeveloped Runoff Coefficient (Cu) 0.8747
Developed Runoff Coefficient (Cd) 0.8752
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 3.4248
Burned Peak Flow Rate (cfs) 3.5694
24-Hr Clear Runoff Volume (ac-ft) 0.147
24-Hr Clear Runoff Volume (cu-ft) 6402.7034
C-23
Item #8. Page 1291
Meeting Date: 1/24/2023 / Packet Page #: 1356
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/25year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID H
Area (ac) 1.5
Flow Path Length (ft) 758.0
Flow Path Slope (vft/hft) 0.26
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.02
Soil Type 81
Design Storm Frequency 25-yr
Fire Factor 0.71
LID False
Output Results
Modeled (25-yr) Rainfall Depth (in) 7.2874
Peak Intensity (in/hr) 4.3479
Undeveloped Runoff Coefficient (Cu) 0.8747
Developed Runoff Coefficient (Cd) 0.8752
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 5.708
Burned Peak Flow Rate (cfs) 5.9491
24-Hr Clear Runoff Volume (ac-ft) 0.245
24-Hr Clear Runoff Volume (cu-ft) 10671.1723
C-24
Item #8. Page 1292
Meeting Date: 1/24/2023 / Packet Page #: 1357
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/25year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID K
Area (ac) 0.7
Flow Path Length (ft) 237.0
Flow Path Slope (vft/hft) 0.21
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.02
Soil Type 81
Design Storm Frequency 25-yr
Fire Factor 0.71
LID False
Output Results
Modeled (25-yr) Rainfall Depth (in) 7.2874
Peak Intensity (in/hr) 4.3479
Undeveloped Runoff Coefficient (Cu) 0.8747
Developed Runoff Coefficient (Cd) 0.8752
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 2.6637
Burned Peak Flow Rate (cfs) 2.7762
24-Hr Clear Runoff Volume (ac-ft) 0.1143
24-Hr Clear Runoff Volume (cu-ft) 4979.8804
C-25
Item #8. Page 1293
Meeting Date: 1/24/2023 / Packet Page #: 1358
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/25year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID L
Area (ac) 0.7
Flow Path Length (ft) 224.0
Flow Path Slope (vft/hft) 0.2
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.02
Soil Type 81
Design Storm Frequency 25-yr
Fire Factor 0.71
LID False
Output Results
Modeled (25-yr) Rainfall Depth (in) 7.2874
Peak Intensity (in/hr) 4.3479
Undeveloped Runoff Coefficient (Cu) 0.8747
Developed Runoff Coefficient (Cd) 0.8752
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 2.6637
Burned Peak Flow Rate (cfs) 2.7762
24-Hr Clear Runoff Volume (ac-ft) 0.1143
24-Hr Clear Runoff Volume (cu-ft) 4979.8804
C-26
Item #8. Page 1294
Meeting Date: 1/24/2023 / Packet Page #: 1359
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/25year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID M
Area (ac) 0.7
Flow Path Length (ft) 310.0
Flow Path Slope (vft/hft) 0.14
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.02
Soil Type 81
Design Storm Frequency 25-yr
Fire Factor 0.71
LID False
Output Results
Modeled (25-yr) Rainfall Depth (in) 7.2874
Peak Intensity (in/hr) 4.3479
Undeveloped Runoff Coefficient (Cu) 0.8747
Developed Runoff Coefficient (Cd) 0.8752
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 2.6637
Burned Peak Flow Rate (cfs) 2.7762
24-Hr Clear Runoff Volume (ac-ft) 0.1143
24-Hr Clear Runoff Volume (cu-ft) 4979.8804
C-27
Item #8. Page 1295
Meeting Date: 1/24/2023 / Packet Page #: 1360
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/25year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID N
Area (ac) 0.5
Flow Path Length (ft) 170.0
Flow Path Slope (vft/hft) 0.31
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.02
Soil Type 81
Design Storm Frequency 25-yr
Fire Factor 0.71
LID False
Output Results
Modeled (25-yr) Rainfall Depth (in) 7.2874
Peak Intensity (in/hr) 4.3479
Undeveloped Runoff Coefficient (Cu) 0.8747
Developed Runoff Coefficient (Cd) 0.8752
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 1.9027
Burned Peak Flow Rate (cfs) 1.983
24-Hr Clear Runoff Volume (ac-ft) 0.0817
24-Hr Clear Runoff Volume (cu-ft) 3557.0574
C-28
Item #8. Page 1296
Meeting Date: 1/24/2023 / Packet Page #: 1361
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/25year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID Lot1b
Area (ac) 0.5
Flow Path Length (ft) 640.0
Flow Path Slope (vft/hft) 0.14
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.21
Soil Type 7
Design Storm Frequency 25-yr
Fire Factor 0.71
LID False
Output Results
Modeled (25-yr) Rainfall Depth (in) 7.2874
Peak Intensity (in/hr) 4.3479
Undeveloped Runoff Coefficient (Cu) 0.7653
Developed Runoff Coefficient (Cd) 0.7936
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 1.7252
Burned Peak Flow Rate (cfs) 1.8581
24-Hr Clear Runoff Volume (ac-ft) 0.095
24-Hr Clear Runoff Volume (cu-ft) 4138.1542
C-29
Item #8. Page 1297
Meeting Date: 1/24/2023 / Packet Page #: 1362
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/25year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID Q
Area (ac) 5.5
Flow Path Length (ft) 898.0
Flow Path Slope (vft/hft) 0.18
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.21
Soil Type 81
Design Storm Frequency 25-yr
Fire Factor 0.71
LID False
Output Results
Modeled (25-yr) Rainfall Depth (in) 7.2874
Peak Intensity (in/hr) 4.3479
Undeveloped Runoff Coefficient (Cu) 0.8747
Developed Runoff Coefficient (Cd) 0.88
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 21.0441
Burned Peak Flow Rate (cfs) 21.8941
24-Hr Clear Runoff Volume (ac-ft) 1.3021
24-Hr Clear Runoff Volume (cu-ft) 56718.8938
C-30
Item #8. Page 1298
Meeting Date: 1/24/2023 / Packet Page #: 1363
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/25year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID R
Area (ac) 4.0
Flow Path Length (ft) 750.0
Flow Path Slope (vft/hft) 0.08
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.21
Soil Type 7
Design Storm Frequency 25-yr
Fire Factor 0.71
LID False
Output Results
Modeled (25-yr) Rainfall Depth (in) 7.2874
Peak Intensity (in/hr) 3.9908
Undeveloped Runoff Coefficient (Cu) 0.7451
Developed Runoff Coefficient (Cd) 0.7776
Time of Concentration (min) 6.0
Clear Peak Flow Rate (cfs) 12.4135
Burned Peak Flow Rate (cfs) 13.4522
24-Hr Clear Runoff Volume (ac-ft) 0.7594
24-Hr Clear Runoff Volume (cu-ft) 33077.3278
C-31
Item #8. Page 1299
Meeting Date: 1/24/2023 / Packet Page #: 1364
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-32
Hydrocalc: 50-Year Storm (Capital Flood)
Note that the Hydrocalc output on the following pages was used to calculate time of concentration ONLY. The flows shown were not used because routing via LAR04 was used instead (output shown later in this appendix).

Item #8. Page 1300
Meeting Date: 1/24/2023 / Packet Page #: 1365
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/50year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID A1
Area (ac) 5.6
Flow Path Length (ft) 971.0
Flow Path Slope (vft/hft) 0.44
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.01
Soil Type 81
Design Storm Frequency 50-yr
Fire Factor 0.71
LID False
Output Results
Modeled (50-yr) Rainfall Depth (in) 8.3
Peak Intensity (in/hr) 4.952
Undeveloped Runoff Coefficient (Cu) 0.8885
Developed Runoff Coefficient (Cd) 0.8886
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 24.6431
Burned Peak Flow Rate (cfs) 25.5748
24-Hr Clear Runoff Volume (ac-ft) 1.1125
24-Hr Clear Runoff Volume (cu-ft) 48458.9635
C-33
Item #8. Page 1301
Meeting Date: 1/24/2023 / Packet Page #: 1366
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/50year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID A2
Area (ac) 4.8
Flow Path Length (ft) 812.0
Flow Path Slope (vft/hft) 0.47
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.01
Soil Type 81
Design Storm Frequency 50-yr
Fire Factor 0.71
LID False
Output Results
Modeled (50-yr) Rainfall Depth (in) 8.3
Peak Intensity (in/hr) 4.952
Undeveloped Runoff Coefficient (Cu) 0.8885
Developed Runoff Coefficient (Cd) 0.8886
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 21.1227
Burned Peak Flow Rate (cfs) 21.9213
24-Hr Clear Runoff Volume (ac-ft) 0.9535
24-Hr Clear Runoff Volume (cu-ft) 41536.2544
C-34
Item #8. Page 1302
Meeting Date: 1/24/2023 / Packet Page #: 1367
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/50year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID A3
Area (ac) 3.6
Flow Path Length (ft) 926.0
Flow Path Slope (vft/hft) 0.38
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.01
Soil Type 81
Design Storm Frequency 50-yr
Fire Factor 0.71
LID False
Output Results
Modeled (50-yr) Rainfall Depth (in) 8.3
Peak Intensity (in/hr) 4.952
Undeveloped Runoff Coefficient (Cu) 0.8885
Developed Runoff Coefficient (Cd) 0.8886
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 15.842
Burned Peak Flow Rate (cfs) 16.4409
24-Hr Clear Runoff Volume (ac-ft) 0.7152
24-Hr Clear Runoff Volume (cu-ft) 31152.1908
C-35
Item #8. Page 1303
Meeting Date: 1/24/2023 / Packet Page #: 1368
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/50year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID A4
Area (ac) 7.0
Flow Path Length (ft) 749.0
Flow Path Slope (vft/hft) 0.58
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.01
Soil Type 81
Design Storm Frequency 50-yr
Fire Factor 0.71
LID False
Output Results
Modeled (50-yr) Rainfall Depth (in) 8.3
Peak Intensity (in/hr) 4.952
Undeveloped Runoff Coefficient (Cu) 0.8885
Developed Runoff Coefficient (Cd) 0.8886
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 30.8039
Burned Peak Flow Rate (cfs) 31.9685
24-Hr Clear Runoff Volume (ac-ft) 1.3906
24-Hr Clear Runoff Volume (cu-ft) 60573.7044
C-36
Item #8. Page 1304
Meeting Date: 1/24/2023 / Packet Page #: 1369
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/50year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72412
Subarea ID A5
Area (ac) 4.7
Flow Path Length (ft) 835.0
Flow Path Slope (vft/hft) 0.32
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.01
Soil Type 81
Design Storm Frequency 50-yr
Fire Factor 0.71
LID False
Output Results
Modeled (50-yr) Rainfall Depth (in) 8.3
Peak Intensity (in/hr) 4.952
Undeveloped Runoff Coefficient (Cu) 0.8885
Developed Runoff Coefficient (Cd) 0.8886
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 20.6826
Burned Peak Flow Rate (cfs) 21.4646
24-Hr Clear Runoff Volume (ac-ft) 0.9337
24-Hr Clear Runoff Volume (cu-ft) 40670.9158
C-37
Item #8. Page 1305
Meeting Date: 1/24/2023 / Packet Page #: 1370
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/50year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID A6
Area (ac) 6.1
Flow Path Length (ft) 886.0
Flow Path Slope (vft/hft) 0.5
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.01
Soil Type 81
Design Storm Frequency 50-yr
Fire Factor 0.71
LID False
Output Results
Modeled (50-yr) Rainfall Depth (in) 8.3
Peak Intensity (in/hr) 4.952
Undeveloped Runoff Coefficient (Cu) 0.8885
Developed Runoff Coefficient (Cd) 0.8886
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 26.8434
Burned Peak Flow Rate (cfs) 27.8583
24-Hr Clear Runoff Volume (ac-ft) 1.2118
24-Hr Clear Runoff Volume (cu-ft) 52785.6567
C-38
Item #8. Page 1306
Meeting Date: 1/24/2023 / Packet Page #: 1371
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/50year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID A7
Area (ac) 5.6
Flow Path Length (ft) 983.0
Flow Path Slope (vft/hft) 0.44
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.01
Soil Type 81
Design Storm Frequency 50-yr
Fire Factor 0.71
LID False
Output Results
Modeled (50-yr) Rainfall Depth (in) 8.3
Peak Intensity (in/hr) 4.952
Undeveloped Runoff Coefficient (Cu) 0.8885
Developed Runoff Coefficient (Cd) 0.8886
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 24.6431
Burned Peak Flow Rate (cfs) 25.5748
24-Hr Clear Runoff Volume (ac-ft) 1.1125
24-Hr Clear Runoff Volume (cu-ft) 48458.9635
C-39
Item #8. Page 1307
Meeting Date: 1/24/2023 / Packet Page #: 1372
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/50year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID A8-1
Area (ac) 3.9
Flow Path Length (ft) 1166.0
Flow Path Slope (vft/hft) 0.23
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.03
Soil Type 81
Design Storm Frequency 50-yr
Fire Factor 0.71
LID False
Output Results
Modeled (50-yr) Rainfall Depth (in) 8.3
Peak Intensity (in/hr) 4.952
Undeveloped Runoff Coefficient (Cu) 0.8885
Developed Runoff Coefficient (Cd) 0.8889
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 17.1666
Burned Peak Flow Rate (cfs) 17.8141
24-Hr Clear Runoff Volume (ac-ft) 0.8077
24-Hr Clear Runoff Volume (cu-ft) 35185.1891
C-40
Item #8. Page 1308
Meeting Date: 1/24/2023 / Packet Page #: 1373
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/50year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72414
Subarea ID A8-2
Area (ac) 5.1
Flow Path Length (ft) 766.0
Flow Path Slope (vft/hft) 0.38
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.01
Soil Type 81
Design Storm Frequency 50-yr
Fire Factor 0.71
LID False
Output Results
Modeled (50-yr) Rainfall Depth (in) 8.3
Peak Intensity (in/hr) 4.952
Undeveloped Runoff Coefficient (Cu) 0.8885
Developed Runoff Coefficient (Cd) 0.8886
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 22.4428
Burned Peak Flow Rate (cfs) 23.2913
24-Hr Clear Runoff Volume (ac-ft) 1.0131
24-Hr Clear Runoff Volume (cu-ft) 44132.2703
C-41
Item #8. Page 1309
Meeting Date: 1/24/2023 / Packet Page #: 1374
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/50year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID A9
Area (ac) 1.5
Flow Path Length (ft) 655.0
Flow Path Slope (vft/hft) 0.28
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.01
Soil Type 81
Design Storm Frequency 50-yr
Fire Factor 0.71
LID False
Output Results
Modeled (50-yr) Rainfall Depth (in) 8.3
Peak Intensity (in/hr) 4.952
Undeveloped Runoff Coefficient (Cu) 0.8885
Developed Runoff Coefficient (Cd) 0.8886
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 6.6008
Burned Peak Flow Rate (cfs) 6.8504
24-Hr Clear Runoff Volume (ac-ft) 0.298
24-Hr Clear Runoff Volume (cu-ft) 12980.0795
C-42
Item #8. Page 1310
Meeting Date: 1/24/2023 / Packet Page #: 1375
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/50year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID A10-1
Area (ac) 1.7
Flow Path Length (ft) 882.0
Flow Path Slope (vft/hft) 0.13
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.01
Soil Type 7
Design Storm Frequency 50-yr
Fire Factor 0.71
LID False
Output Results
Modeled (50-yr) Rainfall Depth (in) 8.3
Peak Intensity (in/hr) 4.952
Undeveloped Runoff Coefficient (Cu) 0.7991
Developed Runoff Coefficient (Cd) 0.8001
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 6.7355
Burned Peak Flow Rate (cfs) 7.2432
24-Hr Clear Runoff Volume (ac-ft) 0.2068
24-Hr Clear Runoff Volume (cu-ft) 9010.1629
C-43
Item #8. Page 1311
Meeting Date: 1/24/2023 / Packet Page #: 1376
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/50year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID A10-2
Area (ac) 1.4
Flow Path Length (ft) 768.0
Flow Path Slope (vft/hft) 0.15
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.01
Soil Type 7
Design Storm Frequency 50-yr
Fire Factor 0.71
LID False
Output Results
Modeled (50-yr) Rainfall Depth (in) 8.3
Peak Intensity (in/hr) 4.952
Undeveloped Runoff Coefficient (Cu) 0.7991
Developed Runoff Coefficient (Cd) 0.8001
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 5.5469
Burned Peak Flow Rate (cfs) 5.965
24-Hr Clear Runoff Volume (ac-ft) 0.1703
24-Hr Clear Runoff Volume (cu-ft) 7420.1342
C-44
Item #8. Page 1312
Meeting Date: 1/24/2023 / Packet Page #: 1377
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/50year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID B1
Area (ac) 5.6
Flow Path Length (ft) 971.0
Flow Path Slope (vft/hft) 0.44
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.01
Soil Type 81
Design Storm Frequency 50-yr
Fire Factor 0.71
LID False
Output Results
Modeled (50-yr) Rainfall Depth (in) 8.3
Peak Intensity (in/hr) 4.952
Undeveloped Runoff Coefficient (Cu) 0.8885
Developed Runoff Coefficient (Cd) 0.8886
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 24.6431
Burned Peak Flow Rate (cfs) 25.5748
24-Hr Clear Runoff Volume (ac-ft) 1.1125
24-Hr Clear Runoff Volume (cu-ft) 48458.9635
C-45
Item #8. Page 1313
Meeting Date: 1/24/2023 / Packet Page #: 1378
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/50year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID B2
Area (ac) 3.6
Flow Path Length (ft) 926.0
Flow Path Slope (vft/hft) 0.38
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.01
Soil Type 81
Design Storm Frequency 50-yr
Fire Factor 0.71
LID False
Output Results
Modeled (50-yr) Rainfall Depth (in) 8.3
Peak Intensity (in/hr) 4.952
Undeveloped Runoff Coefficient (Cu) 0.8885
Developed Runoff Coefficient (Cd) 0.8886
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 15.842
Burned Peak Flow Rate (cfs) 16.4409
24-Hr Clear Runoff Volume (ac-ft) 0.7152
24-Hr Clear Runoff Volume (cu-ft) 31152.1908
C-46
Item #8. Page 1314
Meeting Date: 1/24/2023 / Packet Page #: 1379
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/50year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID B3
Area (ac) 4.8
Flow Path Length (ft) 660.0
Flow Path Slope (vft/hft) 0.38
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.01
Soil Type 81
Design Storm Frequency 50-yr
Fire Factor 0.71
LID False
Output Results
Modeled (50-yr) Rainfall Depth (in) 8.3
Peak Intensity (in/hr) 4.952
Undeveloped Runoff Coefficient (Cu) 0.8885
Developed Runoff Coefficient (Cd) 0.8886
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 21.1227
Burned Peak Flow Rate (cfs) 21.9213
24-Hr Clear Runoff Volume (ac-ft) 0.9535
24-Hr Clear Runoff Volume (cu-ft) 41536.2544
C-47
Item #8. Page 1315
Meeting Date: 1/24/2023 / Packet Page #: 1380
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/50year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID C
Area (ac) 6.6
Flow Path Length (ft) 908.0
Flow Path Slope (vft/hft) 0.48
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.01
Soil Type 81
Design Storm Frequency 50-yr
Fire Factor 0.71
LID False
Output Results
Modeled (50-yr) Rainfall Depth (in) 8.3
Peak Intensity (in/hr) 4.952
Undeveloped Runoff Coefficient (Cu) 0.8885
Developed Runoff Coefficient (Cd) 0.8886
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 29.0437
Burned Peak Flow Rate (cfs) 30.1417
24-Hr Clear Runoff Volume (ac-ft) 1.3111
24-Hr Clear Runoff Volume (cu-ft) 57112.3498
C-48
Item #8. Page 1316
Meeting Date: 1/24/2023 / Packet Page #: 1381
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/50year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID D1
Area (ac) 4.8
Flow Path Length (ft) 812.0
Flow Path Slope (vft/hft) 0.47
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.01
Soil Type 81
Design Storm Frequency 50-yr
Fire Factor 0.71
LID False
Output Results
Modeled (50-yr) Rainfall Depth (in) 8.3
Peak Intensity (in/hr) 4.952
Undeveloped Runoff Coefficient (Cu) 0.8885
Developed Runoff Coefficient (Cd) 0.8886
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 21.1227
Burned Peak Flow Rate (cfs) 21.9213
24-Hr Clear Runoff Volume (ac-ft) 0.9535
24-Hr Clear Runoff Volume (cu-ft) 41536.2544
C-49
Item #8. Page 1317
Meeting Date: 1/24/2023 / Packet Page #: 1382
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/50year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID D2
Area (ac) 7.0
Flow Path Length (ft) 749.0
Flow Path Slope (vft/hft) 0.58
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.01
Soil Type 81
Design Storm Frequency 50-yr
Fire Factor 0.71
LID False
Output Results
Modeled (50-yr) Rainfall Depth (in) 8.3
Peak Intensity (in/hr) 4.952
Undeveloped Runoff Coefficient (Cu) 0.8885
Developed Runoff Coefficient (Cd) 0.8886
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 30.8039
Burned Peak Flow Rate (cfs) 31.9685
24-Hr Clear Runoff Volume (ac-ft) 1.3906
24-Hr Clear Runoff Volume (cu-ft) 60573.7044
C-50
Item #8. Page 1318
Meeting Date: 1/24/2023 / Packet Page #: 1383
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/50year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID D3
Area (ac) 6.2
Flow Path Length (ft) 822.0
Flow Path Slope (vft/hft) 0.53
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.01
Soil Type 81
Design Storm Frequency 50-yr
Fire Factor 0.71
LID False
Output Results
Modeled (50-yr) Rainfall Depth (in) 8.3
Peak Intensity (in/hr) 4.952
Undeveloped Runoff Coefficient (Cu) 0.8885
Developed Runoff Coefficient (Cd) 0.8886
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 27.2834
Burned Peak Flow Rate (cfs) 28.315
24-Hr Clear Runoff Volume (ac-ft) 1.2317
24-Hr Clear Runoff Volume (cu-ft) 53650.9953
C-51
Item #8. Page 1319
Meeting Date: 1/24/2023 / Packet Page #: 1384
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/50year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID F
Area (ac) 0.9
Flow Path Length (ft) 540.0
Flow Path Slope (vft/hft) 0.32
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.02
Soil Type 81
Design Storm Frequency 50-yr
Fire Factor 0.71
LID False
Output Results
Modeled (50-yr) Rainfall Depth (in) 8.3
Peak Intensity (in/hr) 4.952
Undeveloped Runoff Coefficient (Cu) 0.8885
Developed Runoff Coefficient (Cd) 0.8888
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 3.961
Burned Peak Flow Rate (cfs) 4.1106
24-Hr Clear Runoff Volume (ac-ft) 0.1826
24-Hr Clear Runoff Volume (cu-ft) 7953.8534
C-52
Item #8. Page 1320
Meeting Date: 1/24/2023 / Packet Page #: 1385
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/50year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID H
Area (ac) 1.5
Flow Path Length (ft) 758.0
Flow Path Slope (vft/hft) 0.26
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.02
Soil Type 81
Design Storm Frequency 50-yr
Fire Factor 0.71
LID False
Output Results
Modeled (50-yr) Rainfall Depth (in) 8.3
Peak Intensity (in/hr) 4.952
Undeveloped Runoff Coefficient (Cu) 0.8885
Developed Runoff Coefficient (Cd) 0.8888
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 6.6017
Burned Peak Flow Rate (cfs) 6.851
24-Hr Clear Runoff Volume (ac-ft) 0.3043
24-Hr Clear Runoff Volume (cu-ft) 13256.4223
C-53
Item #8. Page 1321
Meeting Date: 1/24/2023 / Packet Page #: 1386
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/50year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID K
Area (ac) 0.7
Flow Path Length (ft) 237.0
Flow Path Slope (vft/hft) 0.21
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.02
Soil Type 81
Design Storm Frequency 50-yr
Fire Factor 0.71
LID False
Output Results
Modeled (50-yr) Rainfall Depth (in) 8.3
Peak Intensity (in/hr) 4.952
Undeveloped Runoff Coefficient (Cu) 0.8885
Developed Runoff Coefficient (Cd) 0.8888
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 3.0808
Burned Peak Flow Rate (cfs) 3.1971
24-Hr Clear Runoff Volume (ac-ft) 0.142
24-Hr Clear Runoff Volume (cu-ft) 6186.3304
C-54
Item #8. Page 1322
Meeting Date: 1/24/2023 / Packet Page #: 1387
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/50year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID L
Area (ac) 0.7
Flow Path Length (ft) 224.0
Flow Path Slope (vft/hft) 0.2
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.02
Soil Type 81
Design Storm Frequency 50-yr
Fire Factor 0.71
LID False
Output Results
Modeled (50-yr) Rainfall Depth (in) 8.3
Peak Intensity (in/hr) 4.952
Undeveloped Runoff Coefficient (Cu) 0.8885
Developed Runoff Coefficient (Cd) 0.8888
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 3.0808
Burned Peak Flow Rate (cfs) 3.1971
24-Hr Clear Runoff Volume (ac-ft) 0.142
24-Hr Clear Runoff Volume (cu-ft) 6186.3304
C-55
Item #8. Page 1323
Meeting Date: 1/24/2023 / Packet Page #: 1388
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/50year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID M
Area (ac) 0.7
Flow Path Length (ft) 310.0
Flow Path Slope (vft/hft) 0.14
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.02
Soil Type 81
Design Storm Frequency 50-yr
Fire Factor 0.71
LID False
Output Results
Modeled (50-yr) Rainfall Depth (in) 8.3
Peak Intensity (in/hr) 4.952
Undeveloped Runoff Coefficient (Cu) 0.8885
Developed Runoff Coefficient (Cd) 0.8888
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 3.0808
Burned Peak Flow Rate (cfs) 3.1971
24-Hr Clear Runoff Volume (ac-ft) 0.142
24-Hr Clear Runoff Volume (cu-ft) 6186.3304
C-56
Item #8. Page 1324
Meeting Date: 1/24/2023 / Packet Page #: 1389
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/50year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID N
Area (ac) 0.5
Flow Path Length (ft) 170.0
Flow Path Slope (vft/hft) 0.31
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.02
Soil Type 81
Design Storm Frequency 50-yr
Fire Factor 0.71
LID False
Output Results
Modeled (50-yr) Rainfall Depth (in) 8.3
Peak Intensity (in/hr) 4.952
Undeveloped Runoff Coefficient (Cu) 0.8885
Developed Runoff Coefficient (Cd) 0.8888
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 2.2006
Burned Peak Flow Rate (cfs) 2.2837
24-Hr Clear Runoff Volume (ac-ft) 0.1014
24-Hr Clear Runoff Volume (cu-ft) 4418.8074
C-57
Item #8. Page 1325
Meeting Date: 1/24/2023 / Packet Page #: 1390
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/50year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID Lot1b
Area (ac) 0.5
Flow Path Length (ft) 640.0
Flow Path Slope (vft/hft) 0.14
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.21
Soil Type 7
Design Storm Frequency 50-yr
Fire Factor 0.71
LID False
Output Results
Modeled (50-yr) Rainfall Depth (in) 8.3
Peak Intensity (in/hr) 4.952
Undeveloped Runoff Coefficient (Cu) 0.7991
Developed Runoff Coefficient (Cd) 0.8203
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 2.031
Burned Peak Flow Rate (cfs) 2.1653
24-Hr Clear Runoff Volume (ac-ft) 0.1109
24-Hr Clear Runoff Volume (cu-ft) 4831.0492
C-58
Item #8. Page 1326
Meeting Date: 1/24/2023 / Packet Page #: 1391
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/50year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID Q
Area (ac) 5.5
Flow Path Length (ft) 898.0
Flow Path Slope (vft/hft) 0.18
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.21
Soil Type 81
Design Storm Frequency 50-yr
Fire Factor 0.71
LID False
Output Results
Modeled (50-yr) Rainfall Depth (in) 8.3
Peak Intensity (in/hr) 4.952
Undeveloped Runoff Coefficient (Cu) 0.8885
Developed Runoff Coefficient (Cd) 0.8909
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 24.2656
Burned Peak Flow Rate (cfs) 25.1618
24-Hr Clear Runoff Volume (ac-ft) 1.5578
24-Hr Clear Runoff Volume (cu-ft) 67858.7605
C-59
Item #8. Page 1327
Meeting Date: 1/24/2023 / Packet Page #: 1392
Peak Flow Hydrologic Analysis
File location: P:/DREA001003 Glendora Hydrology Study/SUBMITTAL 4/hydro/50year.pdf Version: HydroCalc 1.0.2
Input Parameters
Project Name TM 72413
Subarea ID R
Area (ac) 4.0
Flow Path Length (ft) 750.0
Flow Path Slope (vft/hft) 0.08
50-yr Rainfall Depth (in) 8.3
Percent Impervious 0.21
Soil Type 7
Design Storm Frequency 50-yr
Fire Factor 0.71
LID False
Output Results
Modeled (50-yr) Rainfall Depth (in) 8.3
Peak Intensity (in/hr) 4.952
Undeveloped Runoff Coefficient (Cu) 0.7991
Developed Runoff Coefficient (Cd) 0.8203
Time of Concentration (min) 5.0
Clear Peak Flow Rate (cfs) 16.248
Burned Peak Flow Rate (cfs) 17.3221
24-Hr Clear Runoff Volume (ac-ft) 0.8872
24-Hr Clear Runoff Volume (cu-ft) 38648.3935
C-60
Item #8. Page 1328
Meeting Date: 1/24/2023 / Packet Page #: 1393
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-61
Existing Condition Routing in LAR04
Figure C – 1. Existing condition routing schematic in LAR04.

Table C – 1. Existing condition cumulative areas at LAR04 concentration points LAR04 Concentration Point Cumulative drainage subareas as shown in report 1A A1
2A A3, A1
3A A5, A3, A1
4A A8-1,A5,A3,A1
5A Lot1b, A8-1,A5,A3,A1
6B A8-2, A6
7B A8-2, A6, A8-1,A5,A3,A1
8AB Lot1b, A8-2, A6, A8-1,A5,A3,A1
9A A10-1, Lot1b, A8-2, A6, A8-1,A5,A3,A1
10D A2
12D A4, A2
12D A7, A4, A2
13D A9, A7, A4, A2
14D A10-2, A9, A7, A4, A2
15AD A10-1, Lot1b, A8-2, A6, A8-1, A5, A3, A1, A10-2, A9, A7, A4, A2 LEGEND
X1 Subarea
Routing (overland)
Concentration Point
1A
2A
6B
12D
13D
10D
3A
11D
8AB
14D
Existing Conditions Routing Progression AS ENTERED INTO LAR04 A1
A3
A5
A6
A10-2
A9
A2
A4
A7
A8-1
Lot1b
4A
15AD
CP1
A10-1 CP2
A8-2
5A
7B
9A
Item #8. Page 1329
Meeting Date: 1/24/2023 / Packet Page #: 1394
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-62
Existing Condition Clear Water 25-Year Storm (Urban Flood) Program Package Serial Number: 2223
08/01/18 FILE: ex25.i INPUT DATA: English Units RAINFALL SOIL FILE: English (In) OUTPUT DATA: English Units PAGE 1 LOS ANGELES COUNTY FLOOD CONTROL DISTRICT PROG F0601M
Version 11.3, MODIFIED RATIONAL METHOD HYDROLOGY - STORM YEAR = 25 SOIL DATA FILE: C:\LAR04\sgr_soilx_71.dat Glendora STORM DAY 4

SUBAREA SUBAREA TOTAL TOTAL CONV CONV CONV CONV CONV CONTROL SOIL RAIN PCT LOCATION AREA(Ac) Q(CFS) AREA(Ac) Q(CFS) TYPE LNGTH(Ft) SLOPE SIZE(Ft) Z Q(CFS) NAME TC ZONE IMPV 5 1A 5.6 21.69 5.6 21.69 1 611. .26000 .00 .00 0. 81 5 A42 .01 5 2A 3.6 13.95 9.2 31.34 1 757. .24000 .00 .00 0. 81 5 A42 .01 5 3A 4.7 18.21 13.9 42.05 1 806. .12000 .00 .00 0. 81 5 A42 .01 5 4A 3.9 13.52 17.8 46.85 0 0. .00000 .00 .00 0. 81 6 A42 .03 5 5A .5 1.76 18.3 47.51 0 0. .00000 .00 .00 0. 7 5 A42 .21 5 6B 6.1 23.63 6.1 23.63 1 659. .16000 .00 .00 0. 81 5 A42 .01 5 7B 5.1 19.76 11.2 36.31 0 0. .00000 .00 .00 0. 81 5 A42 .01 5 8AB 11.2 36.31 29.5 80.84 1 617. .09000 .00 .00 0. 81 0 A42 .00 5 9A 1.7 5.07 31.2 81.36 0 0. .00000 .00 .00 0. 7 6 A42 .01 5 10D 4.8 18.59 4.8 18.59 1 521. .48000 .00 .00 0. 81 5 A42 .01 5 11D 7.0 27.12 11.8 42.83 1 595. .24000 .00 .00 0. 81 5 A42 .01 5 12D 5.6 21.69 17.4 58.11 1 395. .20000 .00 .00 0. 81 5 A42 .01 5 13D 1.5 5.81 18.9 61.32 1 711. .14000 .00 .00 0. 81 5 A42 .01 5 14D 1.4 4.77 20.3 60.40 0 0. .00000 .00 .00 0. 7 5 A42 .01 5 15AD 20.3 60.40 51.5 141.76 0 0. .00000 .00 .00 0. 7 0 A42 .00 Item #8. Page 1330
Meeting Date: 1/24/2023 / Packet Page #: 1395
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-63
Existing Condition Clear Water 50-Year Storm (Capital Flood) Program Package Serial Number: 2223
08/01/18 FILE: ex50.i INPUT DATA: English Units RAINFALL SOIL FILE: English (In) OUTPUT DATA: English Units PAGE 1 LOS ANGELES COUNTY FLOOD CONTROL DISTRICT PROG F0601M
Version 11.3, MODIFIED RATIONAL METHOD HYDROLOGY - STORM YEAR = 50 SOIL DATA FILE: C:\LAR04\sgr_soilx_71.dat Glendora STORM DAY 4

SUBAREA SUBAREA TOTAL TOTAL CONV CONV CONV CONV CONV CONTROL SOIL RAIN PCT LOCATION AREA(Ac) Q(CFS) AREA(Ac) Q(CFS) TYPE LNGTH(Ft) SLOPE SIZE(Ft) Z Q(CFS) NAME TC ZONE IMPV 5 1A 5.6 25.12 5.6 25.12 1 611. .26000 .00 .00 0. 81 5 A42 .01 5 2A 3.6 16.15 9.2 36.56 1 757. .24000 .00 .00 0. 81 5 A42 .01 5 3A 4.7 21.09 13.9 49.49 1 806. .12000 .00 .00 0. 81 5 A42 .01 5 4A 3.9 15.68 17.8 55.70 0 0. .00000 .00 .00 0. 81 6 A42 .03 5 5A .5 2.06 18.3 56.82 0 0. .00000 .00 .00 0. 7 5 A42 .21 5 6B 6.1 27.37 6.1 27.37 1 659. .16000 .00 .00 0. 81 5 A42 .01 5 7B 5.1 22.88 11.2 42.65 0 0. .00000 .00 .00 0. 81 5 A42 .01 5 8AB 11.2 42.65 29.5 95.99 1 617. .09000 .00 .00 0. 81 0 A42 .00 5 9A 1.7 6.04 31.2 96.62 0 0. .00000 .00 .00 0. 7 6 A42 .01 5 10D 4.8 21.53 4.8 21.53 1 521. .48000 .00 .00 0. 81 5 A42 .01 5 11D 7.0 31.40 11.8 49.82 1 595. .24000 .00 .00 0. 81 5 A42 .01 5 12D 5.6 25.12 17.4 67.98 1 395. .20000 .00 .00 0. 81 5 A42 .01 5 13D 1.5 6.73 18.9 71.63 1 711. .14000 .00 .00 0. 81 5 A42 .01 5 14D 1.4 5.64 20.3 70.68 0 0. .00000 .00 .00 0. 7 5 A42 .01 5 15AD 20.3 70.68 51.5 167.30 0 0. .00000 .00 .00 0. 7 0 A42 .00 Item #8. Page 1331
Meeting Date: 1/24/2023 / Packet Page #: 1396
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-64
Existing Condition Burned 50-Year Storm (Capital Flood) Program Package Serial Number: 2223
08/03/18 FILE: ex50bu INPUT DATA: English Units RAINFALL SOIL FILE: English (In) OUTPUT DATA: English Units PAGE 1 LOS ANGELES COUNTY FLOOD CONTROL DISTRICT PROG F0601M
Version 11.3, MODIFIED RATIONAL METHOD HYDROLOGY - STORM YEAR = 50 SOIL DATA FILE: C:\LAR04\sgr_soilx_71.dat Glendora STORM DAY 4

SUBAREA SUBAREA TOTAL TOTAL CONV CONV CONV CONV CONV CONTROL SOIL RAIN PCT LOCATION AREA(Ac) Q(CFS) AREA(Ac) Q(CFS) TYPE LNGTH(Ft) SLOPE SIZE(Ft) Z Q(CFS) NAME TC ZONE IMPV 5 1A 5.6 26.01 5.6 26.01 1 611. .26000 .00 .00 0. 281 5 A42 .01 5 2A 3.6 16.72 9.2 38.05 1 757. .24000 .00 .00 0. 281 5 A42 .01 5 3A 4.7 21.83 13.9 51.80 1 806. .12000 .00 .00 0. 281 5 A42 .01 5 4A 3.9 16.28 17.8 58.84 0 0. .00000 .00 .00 0. 281 6 A42 .03 5 5A .5 2.18 18.3 60.07 0 0. .00000 .00 .00 0. 207 5 A42 .21 5 6B 6.1 28.33 6.1 28.33 1 659. .16000 .00 .00 0. 281 5 A42 .01 5 7B 5.1 23.68 11.2 44.52 0 0. .00000 .00 .00 0. 281 5 A42 .01 5 8AB 11.2 44.52 29.5 101.11 1 617. .09000 .00 .00 0. 281 0 A42 .00 5 9A 1.7 6.54 31.2 102.12 0 0. .00000 .00 .00 0. 207 6 A42 .01 5 10D 4.8 22.29 4.8 22.29 1 521. .48000 .00 .00 0. 281 5 A42 .01 5 11D 7.0 32.51 11.8 51.71 1 595. .24000 .00 .00 0. 281 5 A42 .01 5 12D 5.6 26.01 17.4 70.83 1 395. .20000 .00 .00 0. 281 5 A42 .01 5 13D 1.5 6.97 18.9 74.76 1 711. .14000 .00 .00 0. 281 5 A42 .01 5 14D 1.4 6.06 20.3 74.41 0 0. .00000 .00 .00 0. 207 5 A42 .01 5 15AD 20.3 74.41 51.5 176.30 0 0. .00000 .00 .00 0. 207 0 A42 .00 Item #8. Page 1332
Meeting Date: 1/24/2023 / Packet Page #: 1397
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-65
Proposed Condition Subarea B Routing in LAR04
A schematic of the proposed condition subarea B routing in shown below, and the LAR04 output is shown on the immediately following pages. A table relating cumulative B subareas as designated in the report and the concentration point definitions in LAR04 is shown below, as well as figure showing a schematic translation between the report subarea B designations to those used in LAR04. The actual LAR04 output is shown on the immediately following pages.

Figure C – 2. Proposed condition subareas B1 – B3 routing schematic in LAR04.

Table C – 2. Proposed condition subareas B1 – B3 cumulative areas at LAR04 concentration points LAR04 Concentration Point Cumulative drainage subareas as shown in report 1A B1
2A B2, B1
3A B3, B2, B1
B1
B2
B3
LEGEND
X1 Subarea
Routing (overland)
Concentration Point
1A
2A
3A
SCHEMATIC IN REPORT AS ENTERED IN LAR04
Item #8. Page 1333
Meeting Date: 1/24/2023 / Packet Page #: 1398
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-66
Subarea B Clear Water 25-Year Storm (Urban Flood)
Program Package Serial Number: 2223
01/18/18 FILE: prpb INPUT DATA: English Units RAINFALL SOIL FILE: English (In) OUTPUT DATA: English Units PAGE 1 LOS ANGELES COUNTY FLOOD CONTROL DISTRICT PROG F0601M
Version 11.3, MODIFIED RATIONAL METHOD HYDROLOGY - STORM YEAR = 25 SOIL DATA FILE: C:\LAR04\sgr_soilx_71.dat Glendora STORM DAY 4

Figure C – 3. Proposed condition subareas C, F, and H routing schematic in LAR04.

Table C – 3. Proposed condition subareas C, F, and H cumulative areas at LAR04 concentration points LAR04 Concentration Point Cumulative drainage subareas as shown in report 1A C
2A F, C
3A H, F, C
LEGEND
X1 Subarea
Routing (overland)
Concentration Point SCHEMATIC IN REPORT AS ENTERED IN LAR04 C
F H
2A
1A
3A
Item #8. Page 1337
Meeting Date: 1/24/2023 / Packet Page #: 1402
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-70
Subareas C, F, and H Clear Water 25-Year Storm (Urban Flood) Program Package Serial Number: 2223
03/02/18 FILE: prpc INPUT DATA: English Units RAINFALL SOIL FILE: English (In) OUTPUT DATA: English Units PAGE 1 LOS ANGELES COUNTY FLOOD CONTROL DISTRICT PROG F0601M
Version 11.3, MODIFIED RATIONAL METHOD HYDROLOGY - STORM YEAR = 25 SOIL DATA FILE: C:\LAR04\cst_soilx_83.dat Glendora STORM DAY 4

Item #8. Page 1338
Meeting Date: 1/24/2023 / Packet Page #: 1403
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-71
Subareas C, F, and H Clear Water 50-Year Storm (Capital Flood) Program Package Serial Number: 2223
03/02/18 FILE: prpc INPUT DATA: English Units RAINFALL SOIL FILE: English (In) OUTPUT DATA: English Units PAGE 1 LOS ANGELES COUNTY FLOOD CONTROL DISTRICT PROG F0601M
Version 11.3, MODIFIED RATIONAL METHOD HYDROLOGY - STORM YEAR = 50 SOIL DATA FILE: C:\LAR04\sgr_soilx_71.dat Glendora STORM DAY 4

SUBAREA SUBAREA TOTAL TOTAL CONV CONV CONV CONV CONV CONTROL SOIL RAIN PCT LOCATION AREA(Ac) Q(CFS) AREA(Ac) Q(CFS) TYPE LNGTH(Ft) SLOPE SIZE(Ft) Z Q(CFS) NAME TC ZONE IMPV 5 1A 6.6 29.61 6.6 29.61 0 0. .00000 .00 .00 0. 81 5 A42 .01 5 2A .9 4.04 7.5 33.65 0 0. .00000 .00 .00 0. 81 5 A42 .02 5 3A 1.5 6.73 9.0 40.38 1 1. .00010 .00 .00 0. 81 5 A42 .02 Item #8. Page 1339
Meeting Date: 1/24/2023 / Packet Page #: 1404
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-72
Subareas C, F, and H Burned 50-Year Storm (Capital Flood) Program Package Serial Number: 2223
03/02/18 FILE: prpcbu INPUT DATA: English Units RAINFALL SOIL FILE: English (In) OUTPUT DATA: English Units PAGE 1 LOS ANGELES COUNTY FLOOD CONTROL DISTRICT PROG F0601M
Version 11.3, MODIFIED RATIONAL METHOD HYDROLOGY - STORM YEAR = 50 SOIL DATA FILE: C:\LAR04\sgr_soilx_71.dat Glendora STORM DAY 4

SUBAREA SUBAREA TOTAL TOTAL CONV CONV CONV CONV CONV CONTROL SOIL RAIN PCT LOCATION AREA(Ac) Q(CFS) AREA(Ac) Q(CFS) TYPE LNGTH(Ft) SLOPE SIZE(Ft) Z Q(CFS) NAME TC ZONE IMPV 5 1A 6.6 30.65 6.6 30.65 0 0. .00000 .00 .00 0. 281 5 A42 .01 5 2A .9 4.18 7.5 34.83 0 0. .00000 .00 .00 0. 281 5 A42 .02 5 3A 1.5 6.96 9.0 41.79 1 1. .00010 .00 .00 0. 281 5 A42 .02 Item #8. Page 1340
Meeting Date: 1/24/2023 / Packet Page #: 1405
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-73
Proposed Condition Subarea D Routing in LAR04
A schematic of the proposed condition subareas D routing in shown below, and the LAR04 output is shown on the immediately following pages. A table relating cumulative D subareas as designated in the report and the concentration point definitions in LAR04 is shown below, as well as figure showing a schematic translation between the report subarea D designations to those used in LAR04. The actual LAR04 output is shown on the immediately following pages.

Figure C – 4. Proposed conditions subareas D1 – D3 routing schematic in LAR04.

Table C – 4. Proposed conditions subareas D1 – D3 cumulative areas at LAR04 concentration points LAR04 Concentration Point Cumulative drainage subareas as shown in report 1A D1
2A D2, D1
3A D3, D2, D1
The LAR04 output for this analysis is shown on the immediately following pages.

LEGEND
X1
X1
X1
Subarea
Routing (overland)
Concentration Point SCHEMATIC IN REPORT AS ENTERED IN LAR04 D1
D2
D3
1A
3A
2A
Item #8. Page 1341
Meeting Date: 1/24/2023 / Packet Page #: 1406
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-74
Subarea D Clear Water 25-Year Storm (Urban Flood)
Program Package Serial Number: 2223
01/18/18 FILE: prpd INPUT DATA: English Units RAINFALL SOIL FILE: English (In) OUTPUT DATA: English Units PAGE 1 LOS ANGELES COUNTY FLOOD CONTROL DISTRICT PROG F0601M
Version 11.3, MODIFIED RATIONAL METHOD HYDROLOGY - STORM YEAR = 25 SOIL DATA FILE: C:\LAR04\sgr_soilx_71.dat Glendora STORM DAY 4

SUBAREA SUBAREA TOTAL TOTAL CONV CONV CONV CONV CONV CONTROL SOIL RAIN PCT LOCATION AREA(Ac) Q(CFS) AREA(Ac) Q(CFS) TYPE LNGTH(Ft) SLOPE SIZE(Ft) Z Q(CFS) NAME TC ZONE IMPV 5 1A 4.8 18.59 4.8 18.59 1 521. .48000 .00 .00 0. 81 5 A42 .01 5 2A 7.0 27.12 11.8 42.83 1 431. .32000 .00 .00 0. 81 5 A42 .01 5 3A 6.2 24.02 18.0 62.18 0 0. .00000 .00 .00 0. 81 5 A42 .01 Item #8. Page 1342
Meeting Date: 1/24/2023 / Packet Page #: 1407
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-75
Subarea D Clear Water 50-Year Storm (Capital Flood)
Program Package Serial Number: 2223
01/18/18 FILE: prpd INPUT DATA: English Units RAINFALL SOIL FILE: English (In) OUTPUT DATA: English Units PAGE 1 LOS ANGELES COUNTY FLOOD CONTROL DISTRICT PROG F0601M
Version 11.3, MODIFIED RATIONAL METHOD HYDROLOGY - STORM YEAR = 50 SOIL DATA FILE: C:\LAR04\sgr_soilx_71.dat Glendora STORM DAY 4

Item #8. Page 1343
Meeting Date: 1/24/2023 / Packet Page #: 1408
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-76
Subarea D Burned 50-Year Storm (Capital Flood)
Program Package Serial Number: 2223
03/02/18 FILE: prpdbu INPUT DATA: English Units RAINFALL SOIL FILE: English (In) OUTPUT DATA: English Units PAGE 1 LOS ANGELES COUNTY FLOOD CONTROL DISTRICT PROG F0601M
Version 11.3, MODIFIED RATIONAL METHOD HYDROLOGY - STORM YEAR = 50 SOIL DATA FILE: C:\LAR04\sgr_soilx_71.dat Glendora STORM DAY 4

SUBAREA SUBAREA TOTAL TOTAL CONV CONV CONV CONV CONV CONTROL SOIL RAIN PCT LOCATION AREA(Ac) Q(CFS) AREA(Ac) Q(CFS) TYPE LNGTH(Ft) SLOPE SIZE(Ft) Z Q(CFS) NAME TC ZONE IMPV 5 1A 4.8 22.29 4.8 22.29 1 521. .48000 .00 .00 0. 281 5 A42 .01 5 2A 7.0 32.51 11.8 51.71 1 431. .32000 .00 .00 0. 281 5 A42 .01 5 3A 6.2 28.79 18.0 75.30 0 0. .00000 .00 .00 0. 281 5 A42 .01 Program Package Serial Number: 2223
03/02/18 FILE: prpdbu INPUT DATA: English Units RAINFALL SOIL FILE: English (In) OUTPUT DATA: English Units PAGE 3 LOS ANGELES COUNTY FLOOD CONTROL DISTRICT PROG F0601M
Item #8. Page 1344
Meeting Date: 1/24/2023 / Packet Page #: 1409
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-77
Detention Analyses with Retard
The detention analyses output from the Retard program is shown on the immediately following pages.

Item #8. Page 1345
Meeting Date: 1/24/2023 / Packet Page #: 1410
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-78
Detention Subarea B Clear Water Urban Flood
CIVILCADD/CIVILDESIGN Engineering Software, (c) 1997-2009 Version 6.5 -------------------------------------------------------------------- Study Date : 03/07/18 Input hydrograph file name : prpb25.hyd Output hydrograph file name: b50.hin
Program computation of outflow v. depth
************************************************************ CALCULATED OUTFLOW DATA AT DEPTH = 1.00(Ft.)
************************************************************ Weir capacity using equation Q = CLH^Exp(Using Feet as units) Weir Length = 3.00(Ft.) C value = 3.00 Exp = 1.50
Weir flow: Depth = H = 1.00(Ft.) Flow = 9.00 (CFS)
Total outflow at this depth = 9.00(CFS)
************************************************************ CALCULATED OUTFLOW DATA AT DEPTH = 2.00(Ft.)
************************************************************ Weir capacity using equation Q = CLH^Exp(Using Feet as units) Weir Length = 3.00(Ft.) C value = 3.00 Exp = 1.50
Weir flow: Depth = H = 2.00(Ft.) Flow = 25.46 (CFS)
Total outflow at this depth = 25.46(CFS)
************************************************************ CALCULATED OUTFLOW DATA AT DEPTH = 3.00(Ft.)
************************************************************ Weir capacity using equation Q = CLH^Exp(Using Feet as units) Weir Length = 3.00(Ft.) C value = 3.00 Exp = 1.50
Weir flow: Depth = H = 3.00(Ft.) Flow = 46.77 (CFS)
Total outflow at this depth = 46.77(CFS)
************************************************************ CALCULATED OUTFLOW DATA AT DEPTH = 4.00(Ft.)
************************************************************ Weir capacity using equation Q = CLH^Exp(Using Feet as units) Weir Length = 3.00(Ft.) C value = 3.00 Exp = 1.50
Weir flow: Depth = H = 4.00(Ft.) Flow = 72.00 (CFS)
Total outflow at this depth = 72.00(CFS)
************************************************************ CALCULATED OUTFLOW DATA AT DEPTH = 5.00(Ft.)
************************************************************ Weir capacity using equation Q = CLH^Exp(Using Feet as units) Weir Length = 3.00(Ft.) C value = 3.00 Exp = 1.50
Weir flow: Depth = H = 5.00(Ft.) Flow = 100.62 (CFS)
Total outflow at this depth = 100.62(CFS)
-------------------------------------------------------------------- Hydrograph time unit varies
Initial depth in storage basin = 0.00(Ft.)
-------------------------------------------------------------------- -------------------------------------------------------------------- Initial basin depth = 0.00 (Ft.)
Initial basin storage = 0.00 (Ac.Ft)
Initial basin outflow = 0.00 (CFS)
--------------------------------------------------------------------- -------------------------------------------------------------------- Item #8. Page 1346
Meeting Date: 1/24/2023 / Packet Page #: 1411
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-79
Depth vs. Storage and Depth vs. Discharge data @ 1 Min. Intervals:

Basin Depth Storage Outflow (S-O*dt/2) (S+O*dt/2)
(Ft.) (Ac.Ft) (CFS) (Ac.Ft) (Ac.Ft)
---------------------------------------------------------------------

0.000 0.000 0.000 0.000 0.000

1.000 0.060 9.000 0.054 0.066

2.000 0.150 25.456 0.132 0.168

3.000 0.300 46.765 0.268 0.332

4.000 0.500 72.000 0.450 0.550

5.000 0.750 100.623 0.681 0.819
-------------------------------------------------------------------- Hydrograph Detention Basin Routing
Hydrograph at 5 3 A Storm Day: 4 Drainage Area = 14.00
Total flood hydrograph volume this storm day = 2.23 Ac. Ft. --------------------------------------------------------------------- Graph values: 'I'= unit inflow; 'O'=outflow at time shown --------------------------------------------------------------------- Time Inflow Outflow Storage Depth
(Min) (CFS) (CFS) (Ac.Ft) .0 11.2 22.3 33.5 44.6 (Ft.)
0 0.0 0.1 0.000 O | | | | 0.0
100 0.3 0.3 0.002 O | | | | 0.0
200 0.3 0.3 0.002 O | | | | 0.0
300 0.3 0.3 0.002 O | | | | 0.0
400 0.3 0.3 0.002 O | | | | 0.0
500 0.3 0.3 0.002 O | | | | 0.0
600 0.3 0.3 0.002 O | | | | 0.0
700 0.4 0.4 0.003 O | | | | 0.0
800 0.4 0.4 0.003 O | | | | 0.0
900 0.6 0.6 0.004 O | | | | 0.1
1000 1.2 1.2 0.008 O | | | | 0.1
1050 2.0 1.9 0.013 |O | | | | 0.2
1100 3.4 3.3 0.022 | O | | | | 0.4
1110 4.6 4.1 0.028 | OI | | | | 0.5
1120 5.8 5.3 0.035 | OI | | | | 0.6
1130 7.3 6.7 0.044 | OI | | | | 0.7
1131 7.4 6.8 0.045 | OI | | | | 0.8
1132 7.6 7.0 0.046 | OI | | | | 0.8
1133 7.9 7.1 0.048 | O | | | | 0.8
1134 8.2 7.3 0.049 | O | | | | 0.8
1135 8.6 7.6 0.050 | OI | | | | 0.8
1136 8.9 7.8 0.052 | OI | | | | 0.9
1137 9.3 8.1 0.054 | OI | | | | 0.9
1138 9.7 8.4 0.056 | O | | | | 0.9
1139 10.1 8.7 0.058 | OI| | | | 1.0
1140 10.5 9.1 0.060 | OI| | | | 1.0
1141 11.2 9.5 0.063 | O I | | | 1.0
1142 11.7 10.0 0.066 | OI | | | 1.1
1143 12.2 10.5 0.068 | OI | | | 1.1
1144 12.9 11.0 0.071 | O|I | | | 1.1
1145 13.8 11.7 0.075 | OI | | | 1.2
1146 14.8 12.4 0.078 | O I | | | 1.2
1147 15.8 13.1 0.083 | |O I | | | 1.3
1148 16.8 14.0 0.087 | | O I | | | 1.3
1149 20.3 15.4 0.095 | | O I | | | 1.4
1150 24.3 17.4 0.106 | | O |I | | 1.5
1151 29.3 20.0 0.120 | | O | I | | 1.7
1152 35.5 23.5 0.139 | | O |I | 1.9
1153 42.5 27.3 0.163 | | | O | I | 2.1
1154 44.6 30.4 0.185 | | | O | I 2.2
1155 44.0 32.8 0.202 | | | O| I| 2.3
1156 40.2 34.1 0.211 | | | O I | 2.4
1157 34.2 34.1 0.211 | | | O | 2.4
1158 26.9 32.8 0.202 | | | I O| | 2.3
1159 21.7 30.9 0.188 | | I| O | | 2.3
1160 17.4 28.5 0.171 | | I | O | | 2.1
1161 14.2 25.9 0.153 | | I | O | | 2.0
1162 11.7 22.9 0.136 | I O | | 1.8
1163 10.0 20.0 0.120 | I| O | | | 1.7
1164 8.7 17.5 0.106 | I | O | | | 1.5
1165 7.8 15.3 0.094 | I | O | | | 1.4
1166 7.0 13.4 0.084 | I |O | | | 1.3
1167 6.4 11.9 0.076 | I O | | | 1.2
1168 5.9 10.5 0.068 | I O| | | | 1.1
1169 5.5 9.4 0.062 | I O | | | | 1.0
1170 5.2 8.6 0.057 | I O | | | | 1.0
Item #8. Page 1347
Meeting Date: 1/24/2023 / Packet Page #: 1412
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-80
1171 4.9 7.9 0.052 | I O | | | | 0.9
1172 4.6 7.3 0.048 | I O | | | | 0.8
1173 4.3 6.7 0.045 | IO | | | | 0.7
1174 4.1 6.2 0.041 | I O | | | | 0.7
1175 3.9 5.8 0.039 | I O | | | | 0.6
1176 3.7 5.4 0.036 | IO | | | | 0.6
1177 3.5 5.0 0.034 | IO | | | | 0.6
1178 3.4 4.7 0.032 | IO | | | | 0.5
1179 3.2 4.4 0.030 | IO | | | | 0.5
1180 3.1 4.2 0.028 | IO | | | | 0.5
1181 3.0 4.0 0.026 | O | | | | 0.4
1182 2.9 3.8 0.025 | O | | | | 0.4
1183 2.8 3.6 0.024 | O | | | | 0.4
1184 2.6 3.4 0.023 |IO | | | | 0.4
1185 2.6 3.3 0.022 |IO | | | | 0.4
1186 2.4 3.1 0.021 |IO | | | | 0.3
1187 2.4 3.0 0.020 |IO | | | | 0.3
1188 2.3 2.8 0.019 |IO | | | | 0.3
1189 2.2 2.7 0.018 |O | | | | 0.3
1190 2.1 2.6 0.017 |O | | | | 0.3
1191 2.1 2.5 0.017 |O | | | | 0.3
1192 2.0 2.4 0.016 |O | | | | 0.3
1193 2.0 2.3 0.016 |O | | | | 0.3
1194 1.9 2.3 0.015 |O | | | | 0.3
1195 1.9 2.2 0.015 |O | | | | 0.2
1196 1.8 2.1 0.014 |O | | | | 0.2
1197 1.8 2.1 0.014 |O | | | | 0.2
1198 1.7 2.0 0.013 |O | | | | 0.2
1199 1.7 1.9 0.013 |O | | | | 0.2
1200 1.6 1.9 0.012 |O | | | | 0.2
1201 1.6 1.8 0.012 |O | | | | 0.2
1202 1.5 1.8 0.012 |O | | | | 0.2
1203 1.5 1.7 0.011 |O | | | | 0.2
1204 1.4 1.7 0.011 |O | | | | 0.2
1205 1.4 1.6 0.011 |O | | | | 0.2
1206 1.4 1.6 0.010 |O | | | | 0.2
1207 1.4 1.5 0.010 |O | | | | 0.2
1208 1.3 1.5 0.010 IO | | | | 0.2
1209 1.3 1.5 0.010 IO | | | | 0.2
1210 1.3 1.4 0.010 IO | | | | 0.2
1211 1.2 1.4 0.009 O | | | | 0.2
1212 1.2 1.3 0.009 O | | | | 0.1
1213 1.2 1.3 0.009 O | | | | 0.1
1214 1.1 1.3 0.009 O | | | | 0.1
1215 1.1 1.2 0.008 O | | | | 0.1
1216 1.1 1.2 0.008 O | | | | 0.1
1217 1.0 1.2 0.008 O | | | | 0.1
1218 1.0 1.1 0.008 O | | | | 0.1
1219 1.0 1.1 0.007 O | | | | 0.1
1220 1.0 1.1 0.007 O | | | | 0.1
1221 0.9 1.1 0.007 O | | | | 0.1
1222 0.9 1.0 0.007 O | | | | 0.1
1223 0.9 1.0 0.007 O | | | | 0.1
1224 0.9 1.0 0.007 O | | | | 0.1
1225 0.9 1.0 0.006 O | | | | 0.1
1226 0.8 0.9 0.006 O | | | | 0.1
1227 0.8 0.9 0.006 O | | | | 0.1
1228 0.8 0.9 0.006 O | | | | 0.1
1229 0.8 0.9 0.006 O | | | | 0.1
1230 0.7 0.8 0.006 O | | | | 0.1
1231 0.7 0.8 0.005 O | | | | 0.1
1232 0.7 0.8 0.005 O | | | | 0.1
1233 0.7 0.8 0.005 O | | | | 0.1
1234 0.7 0.8 0.005 O | | | | 0.1
1235 0.6 0.7 0.005 O | | | | 0.1
1236 0.6 0.7 0.005 O | | | | 0.1
1237 0.6 0.7 0.005 O | | | | 0.1
1238 0.6 0.7 0.004 O | | | | 0.1
1239 0.6 0.7 0.004 O | | | | 0.1
1240 0.5 0.6 0.004 O | | | | 0.1
1241 0.6 0.6 0.004 O | | | | 0.1
1242 0.5 0.6 0.004 O | | | | 0.1
1243 0.5 0.6 0.004 O | | | | 0.1
1244 0.5 0.6 0.004 O | | | | 0.1
1245 0.5 0.6 0.004 O | | | | 0.1
1246 0.5 0.5 0.004 O | | | | 0.1
Item #8. Page 1348
Meeting Date: 1/24/2023 / Packet Page #: 1413
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-81
1247 0.5 0.5 0.004 O | | | | 0.1
1248 0.5 0.5 0.004 O | | | | 0.1
1249 0.5 0.5 0.003 O | | | | 0.1
1250 0.5 0.5 0.003 O | | | | 0.1
1251 0.5 0.5 0.003 O | | | | 0.1
1252 0.5 0.5 0.003 O | | | | 0.1
1253 0.4 0.5 0.003 O | | | | 0.1
1254 0.4 0.5 0.003 O | | | | 0.1
1255 0.4 0.5 0.003 O | | | | 0.1
1256 0.4 0.4 0.003 O | | | | 0.0
1257 0.4 0.4 0.003 O | | | | 0.0
1258 0.4 0.4 0.003 O | | | | 0.0
1259 0.4 0.4 0.003 O | | | | 0.0
1260 0.4 0.4 0.003 O | | | | 0.0
1261 0.4 0.4 0.003 O | | | | 0.0
1262 0.4 0.4 0.003 O | | | | 0.0
1263 0.4 0.4 0.003 O | | | | 0.0
1264 0.4 0.4 0.003 O | | | | 0.0
1265 0.4 0.4 0.003 O | | | | 0.0
1266 0.4 0.4 0.003 O | | | | 0.0
1267 0.4 0.4 0.003 O | | | | 0.0
1268 0.4 0.4 0.003 O | | | | 0.0
1269 0.4 0.4 0.003 O | | | | 0.0
1270 0.4 0.4 0.003 O | | | | 0.0
1271 0.4 0.4 0.003 O | | | | 0.0
1272 0.4 0.4 0.003 O | | | | 0.0
1273 0.4 0.4 0.003 O | | | | 0.0
1274 0.4 0.4 0.003 O | | | | 0.0
1275 0.4 0.4 0.003 O | | | | 0.0
1276 0.4 0.4 0.003 O | | | | 0.0
1277 0.4 0.4 0.003 O | | | | 0.0
1278 0.4 0.4 0.003 O | | | | 0.0
1279 0.4 0.4 0.003 O | | | | 0.0
1280 0.4 0.4 0.003 O | | | | 0.0
1281 0.4 0.4 0.003 O | | | | 0.0
1282 0.4 0.4 0.003 O | | | | 0.0
1283 0.4 0.4 0.003 O | | | | 0.0
1284 0.4 0.4 0.003 O | | | | 0.0
1285 0.4 0.4 0.003 O | | | | 0.0
1286 0.4 0.4 0.003 O | | | | 0.0
1287 0.4 0.4 0.003 O | | | | 0.0
1288 0.4 0.4 0.003 O | | | | 0.0
1289 0.4 0.4 0.003 O | | | | 0.0
1290 0.4 0.4 0.003 O | | | | 0.0
1291 0.4 0.4 0.003 O | | | | 0.0
1292 0.4 0.4 0.003 O | | | | 0.0
1293 0.4 0.4 0.003 O | | | | 0.0
1294 0.4 0.4 0.003 O | | | | 0.0
1295 0.4 0.4 0.003 O | | | | 0.0
1296 0.4 0.4 0.003 O | | | | 0.0
1297 0.4 0.4 0.003 O | | | | 0.0
1298 0.3 0.4 0.003 O | | | | 0.0
1299 0.3 0.4 0.002 O | | | | 0.0
1300 0.4 0.4 0.002 O | | | | 0.0
1310 0.3 0.3 0.002 O | | | | 0.0
1320 0.3 0.3 0.002 O | | | | 0.0
1330 0.3 0.3 0.002 O | | | | 0.0
1340 0.3 0.3 0.002 O | | | | 0.0
1350 0.3 0.3 0.002 O | | | | 0.0
1360 0.3 0.3 0.002 O | | | | 0.0
1370 0.3 0.3 0.002 O | | | | 0.0
1380 0.3 0.3 0.002 O | | | | 0.0
1390 0.3 0.3 0.002 O | | | | 0.0
1400 0.3 0.3 0.002 O | | | | 0.0
1420 0.3 0.3 0.002 O | | | | 0.0
1440 0.3 0.3 0.002 O | | | | 0.0
1460 0.2 0.2 0.001 O | | | | 0.0
1500 0.2 0.2 0.001 O | | | | 0.0
Remaining water in basin = 0.00 (Ac.Ft)
Peak flow out of basin = 34.13(CFS)
Peak flow time = 1157 Min., time interval # = 43
Maximum depth in basin = 2.41(Ft.)
Item #8. Page 1349
Meeting Date: 1/24/2023 / Packet Page #: 1414
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-82
Detention Subarea B Clear Water Capital Flood
CIVILCADD/CIVILDESIGN Engineering Software, (c) 1997-2009 Version 6.5 -------------------------------------------------------------------- Study Date : 03/07/18 Input hydrograph file name : prpb.hyd Output hydrograph file name: b50.hin
Program computation of outflow v. depth
************************************************************ CALCULATED OUTFLOW DATA AT DEPTH = 1.00(Ft.)
************************************************************ Weir capacity using equation Q = CLH^Exp(Using Feet as units) Weir Length = 3.00(Ft.) C value = 3.00 Exp = 1.50
Weir flow: Depth = H = 1.00(Ft.) Flow = 9.00 (CFS)
Total outflow at this depth = 9.00(CFS)
************************************************************ CALCULATED OUTFLOW DATA AT DEPTH = 2.00(Ft.)
************************************************************ Weir capacity using equation Q = CLH^Exp(Using Feet as units) Weir Length = 3.00(Ft.) C value = 3.00 Exp = 1.50
Weir flow: Depth = H = 2.00(Ft.) Flow = 25.46 (CFS)
Total outflow at this depth = 25.46(CFS)
************************************************************ CALCULATED OUTFLOW DATA AT DEPTH = 3.00(Ft.)
************************************************************ Weir capacity using equation Q = CLH^Exp(Using Feet as units) Weir Length = 3.00(Ft.) C value = 3.00 Exp = 1.50
Weir flow: Depth = H = 3.00(Ft.) Flow = 46.77 (CFS)
Total outflow at this depth = 46.77(CFS)
************************************************************ CALCULATED OUTFLOW DATA AT DEPTH = 4.00(Ft.)
************************************************************ Weir capacity using equation Q = CLH^Exp(Using Feet as units) Weir Length = 3.00(Ft.) C value = 3.00 Exp = 1.50
Weir flow: Depth = H = 4.00(Ft.) Flow = 72.00 (CFS)
Total outflow at this depth = 72.00(CFS)
************************************************************ CALCULATED OUTFLOW DATA AT DEPTH = 5.00(Ft.)
************************************************************ Weir capacity using equation Q = CLH^Exp(Using Feet as units) Weir Length = 3.00(Ft.) C value = 3.00 Exp = 1.50
Weir flow: Depth = H = 5.00(Ft.) Flow = 100.62 (CFS)
Total outflow at this depth = 100.62(CFS)
-------------------------------------------------------------------- Hydrograph time unit varies
Initial depth in storage basin = 0.00(Ft.)
-------------------------------------------------------------------- -------------------------------------------------------------------- Initial basin depth = 0.00 (Ft.)
Initial basin storage = 0.00 (Ac.Ft)
Initial basin outflow = 0.00 (CFS)
--------------------------------------------------------------------- -------------------------------------------------------------------- Depth vs. Storage and Depth vs. Discharge data @ 1 Min. Intervals:

Item #8. Page 1350
Meeting Date: 1/24/2023 / Packet Page #: 1415
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-83
Basin Depth Storage Outflow (S-O*dt/2) (S+O*dt/2)
(Ft.) (Ac.Ft) (CFS) (Ac.Ft) (Ac.Ft)
---------------------------------------------------------------------

0.000 0.000 0.000 0.000 0.000

1.000 0.060 9.000 0.054 0.066

2.000 0.150 25.456 0.132 0.168

3.000 0.300 46.765 0.268 0.332

4.000 0.500 72.000 0.450 0.550

5.000 0.750 100.623 0.681 0.819
-------------------------------------------------------------------- Hydrograph Detention Basin Routing
Hydrograph at 5 3 A Storm Day: 4 Drainage Area = 14.00
Total flood hydrograph volume this storm day = 2.76 Ac. Ft. --------------------------------------------------------------------- Graph values: 'I'= unit inflow; 'O'=outflow at time shown --------------------------------------------------------------------- Time Inflow Outflow Storage Depth
(Min) (CFS) (CFS) (Ac.Ft) .0 13.1 26.2 39.3 52.4 (Ft.)
0 0.0 0.1 0.000 O | | | | 0.0
100 0.3 0.3 0.002 O | | | | 0.0
200 0.3 0.3 0.002 O | | | | 0.0
300 0.3 0.3 0.002 O | | | | 0.0
400 0.3 0.3 0.002 O | | | | 0.0
500 0.4 0.4 0.003 O | | | | 0.0
600 0.4 0.4 0.003 O | | | | 0.0
700 0.4 0.4 0.003 O | | | | 0.0
800 0.6 0.6 0.004 O | | | | 0.1
900 1.0 1.0 0.007 O | | | | 0.1
1000 1.7 1.7 0.011 |O | | | | 0.2
1050 2.7 2.6 0.017 |O | | | | 0.3
1100 4.3 4.2 0.028 | O | | | | 0.5
1110 5.8 5.2 0.035 | O | | | | 0.6
1120 7.1 6.5 0.044 | OI | | | | 0.7
1130 8.8 8.1 0.054 | OI | | | | 0.9
1131 9.0 8.3 0.055 | O | | | | 0.9
1132 9.3 8.5 0.056 | O | | | | 0.9
1133 9.6 8.7 0.058 | O | | | | 1.0
1134 10.0 8.9 0.059 | OI | | | | 1.0
1135 10.4 9.2 0.061 | OI | | | | 1.0
1136 10.8 9.6 0.063 | OI | | | | 1.0
1137 11.3 10.0 0.065 | O | | | | 1.1
1138 11.8 10.4 0.068 | OI| | | | 1.1
1139 12.2 10.8 0.070 | OI| | | | 1.1
1140 12.7 11.2 0.072 | OI| | | | 1.1
1141 13.4 11.7 0.075 | OI | | | 1.2
1142 14.0 12.2 0.078 | OI | | | 1.2
1143 14.7 12.8 0.081 | OI | | | 1.2
1144 15.4 13.4 0.084 | OI | | | 1.3
1145 16.5 14.1 0.088 | O I | | | 1.3
1146 17.6 14.9 0.092 | |OI | | | 1.4
1147 18.8 15.7 0.097 | |O I | | | 1.4
1148 20.1 16.7 0.102 | | O I | | | 1.5
1149 24.1 18.4 0.111 | | O I | | | 1.6
1150 28.8 20.7 0.124 | | O |I | | 1.7
1151 34.7 23.8 0.141 | | O | I | | 1.9
1152 42.0 27.4 0.164 | | O |I | 2.1
1153 50.1 31.4 0.192 | | | O | I | 2.3
1154 52.4 35.2 0.218 | | | O | I 2.5
1155 51.4 38.1 0.239 | | | O| I| 2.6
1156 46.7 39.6 0.250 | | | O I | 2.7
1157 39.5 39.6 0.249 | | | O | 2.7
1158 31.0 38.1 0.239 | | | I O| | 2.6
1159 24.9 35.7 0.222 | | I| O | | 2.5
1160 19.9 32.9 0.202 | | I | O | | 2.3
1161 16.3 29.9 0.182 | |I | O | | 2.2
1162 13.5 27.0 0.161 | I O | | 2.1
1163 11.6 24.0 0.142 | I| O | | | 1.9
1164 10.2 20.9 0.125 | I | O | | | 1.7
1165 9.1 18.2 0.111 | I | O | | | 1.6
1166 8.3 16.0 0.098 | I |O | | | 1.4
1167 7.7 14.2 0.088 | I O | | | 1.3
1168 7.1 12.6 0.080 | I O| | | | 1.2
1169 6.6 11.2 0.072 | I O | | | | 1.1
1170 6.2 10.1 0.066 | I O | | | | 1.1
Item #8. Page 1351
Meeting Date: 1/24/2023 / Packet Page #: 1416
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-84
1171 5.9 9.2 0.061 | I O | | | | 1.0
1172 5.6 8.5 0.056 | I O | | | | 0.9
1173 5.3 7.9 0.053 | IO | | | | 0.9
1174 5.1 7.4 0.049 | IO | | | | 0.8
1175 4.9 6.9 0.046 | I O | | | | 0.8
1176 4.6 6.5 0.043 | IO | | | | 0.7
1177 4.4 6.1 0.041 | IO | | | | 0.7
1178 4.3 5.7 0.038 | IO | | | | 0.6
1179 4.1 5.4 0.036 | IO | | | | 0.6
1180 3.9 5.2 0.034 | IO | | | | 0.6
1181 3.8 4.9 0.033 | O | | | | 0.5
1182 3.7 4.7 0.031 | O | | | | 0.5
1183 3.5 4.5 0.030 | O | | | | 0.5
1184 3.4 4.3 0.028 | O | | | | 0.5
1185 3.3 4.1 0.027 | O | | | | 0.5
1186 3.1 3.9 0.026 |IO | | | | 0.4
1187 3.1 3.7 0.025 |IO | | | | 0.4
1188 2.9 3.6 0.024 |IO | | | | 0.4
1189 2.9 3.5 0.023 |IO | | | | 0.4
1190 2.8 3.3 0.022 |IO | | | | 0.4
1191 2.7 3.2 0.021 |O | | | | 0.4
1192 2.6 3.1 0.021 |O | | | | 0.3
1193 2.5 3.0 0.020 |O | | | | 0.3
1194 2.5 2.9 0.019 |O | | | | 0.3
1195 2.4 2.8 0.019 |O | | | | 0.3
1196 2.4 2.7 0.018 |O | | | | 0.3
1197 2.3 2.6 0.018 |O | | | | 0.3
1198 2.2 2.6 0.017 |O | | | | 0.3
1199 2.2 2.5 0.017 |O | | | | 0.3
1200 2.2 2.4 0.016 |O | | | | 0.3
1201 2.1 2.4 0.016 |O | | | | 0.3
1202 2.0 2.3 0.015 |O | | | | 0.3
1203 2.0 2.2 0.015 |O | | | | 0.2
1204 1.9 2.2 0.015 |O | | | | 0.2
1205 1.9 2.1 0.014 |O | | | | 0.2
1206 1.9 2.1 0.014 |O | | | | 0.2
1207 1.8 2.0 0.014 |O | | | | 0.2
1208 1.8 2.0 0.013 |O | | | | 0.2
1209 1.8 2.0 0.013 |O | | | | 0.2
1210 1.7 1.9 0.013 |O | | | | 0.2
1211 1.7 1.9 0.012 |O | | | | 0.2
1212 1.7 1.8 0.012 |O | | | | 0.2
1213 1.6 1.8 0.012 IO | | | | 0.2
1214 1.6 1.8 0.012 IO | | | | 0.2
1215 1.6 1.7 0.012 IO | | | | 0.2
1216 1.5 1.7 0.011 IO | | | | 0.2
1217 1.5 1.6 0.011 IO | | | | 0.2
1218 1.4 1.6 0.011 O | | | | 0.2
1219 1.5 1.6 0.011 O | | | | 0.2
1220 1.4 1.5 0.010 O | | | | 0.2
1221 1.4 1.5 0.010 O | | | | 0.2
1222 1.4 1.5 0.010 O | | | | 0.2
1223 1.3 1.5 0.010 O | | | | 0.2
1224 1.3 1.4 0.010 O | | | | 0.2
1225 1.3 1.4 0.009 O | | | | 0.2
1226 1.3 1.4 0.009 O | | | | 0.2
1227 1.2 1.4 0.009 O | | | | 0.2
1228 1.2 1.3 0.009 O | | | | 0.1
1229 1.2 1.3 0.009 O | | | | 0.1
1230 1.2 1.3 0.009 O | | | | 0.1
1231 1.1 1.2 0.008 O | | | | 0.1
1232 1.1 1.2 0.008 O | | | | 0.1
1233 1.1 1.2 0.008 O | | | | 0.1
1234 1.0 1.2 0.008 O | | | | 0.1
1235 1.0 1.1 0.008 O | | | | 0.1
1236 1.0 1.1 0.007 O | | | | 0.1
1237 1.0 1.1 0.007 O | | | | 0.1
1238 0.9 1.1 0.007 O | | | | 0.1
1239 1.0 1.0 0.007 O | | | | 0.1
1240 0.9 1.0 0.007 O | | | | 0.1
1241 1.0 1.0 0.007 O | | | | 0.1
1242 0.9 1.0 0.007 O | | | | 0.1
1243 0.9 1.0 0.006 O | | | | 0.1
1244 0.9 1.0 0.006 O | | | | 0.1
1245 0.9 0.9 0.006 O | | | | 0.1
1246 0.8 0.9 0.006 O | | | | 0.1
Item #8. Page 1352
Meeting Date: 1/24/2023 / Packet Page #: 1417
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-85
1247 0.8 0.9 0.006 O | | | | 0.1
1248 0.8 0.9 0.006 O | | | | 0.1
1249 0.8 0.9 0.006 O | | | | 0.1
1250 0.8 0.9 0.006 O | | | | 0.1
1251 0.8 0.8 0.006 O | | | | 0.1
1252 0.8 0.8 0.006 O | | | | 0.1
1253 0.7 0.8 0.005 O | | | | 0.1
1254 0.7 0.8 0.005 O | | | | 0.1
1255 0.7 0.8 0.005 O | | | | 0.1
1256 0.7 0.8 0.005 O | | | | 0.1
1257 0.7 0.7 0.005 O | | | | 0.1
1258 0.7 0.7 0.005 O | | | | 0.1
1259 0.6 0.7 0.005 O | | | | 0.1
1260 0.6 0.7 0.005 O | | | | 0.1
1261 0.6 0.7 0.004 O | | | | 0.1
1262 0.6 0.7 0.004 O | | | | 0.1
1263 0.6 0.6 0.004 O | | | | 0.1
1264 0.6 0.6 0.004 O | | | | 0.1
1265 0.6 0.6 0.004 O | | | | 0.1
1266 0.6 0.6 0.004 O | | | | 0.1
1267 0.5 0.6 0.004 O | | | | 0.1
1268 0.5 0.6 0.004 O | | | | 0.1
1269 0.5 0.6 0.004 O | | | | 0.1
1270 0.5 0.6 0.004 O | | | | 0.1
1271 0.5 0.5 0.004 O | | | | 0.1
1272 0.5 0.5 0.004 O | | | | 0.1
1273 0.5 0.5 0.004 O | | | | 0.1
1274 0.5 0.5 0.003 O | | | | 0.1
1275 0.5 0.5 0.003 O | | | | 0.1
1276 0.5 0.5 0.003 O | | | | 0.1
1277 0.5 0.5 0.003 O | | | | 0.1
1278 0.5 0.5 0.003 O | | | | 0.1
1279 0.5 0.5 0.003 O | | | | 0.1
1280 0.4 0.5 0.003 O | | | | 0.1
1281 0.4 0.5 0.003 O | | | | 0.1
1282 0.4 0.5 0.003 O | | | | 0.1
1283 0.4 0.4 0.003 O | | | | 0.0
1284 0.4 0.4 0.003 O | | | | 0.0
1285 0.4 0.4 0.003 O | | | | 0.0
1286 0.4 0.4 0.003 O | | | | 0.0
1287 0.4 0.4 0.003 O | | | | 0.0
1288 0.4 0.4 0.003 O | | | | 0.0
1289 0.4 0.4 0.003 O | | | | 0.0
1290 0.4 0.4 0.003 O | | | | 0.0
1291 0.4 0.4 0.003 O | | | | 0.0
1292 0.4 0.4 0.003 O | | | | 0.0
1293 0.4 0.4 0.003 O | | | | 0.0
1294 0.4 0.4 0.003 O | | | | 0.0
1295 0.4 0.4 0.003 O | | | | 0.0
1296 0.4 0.4 0.003 O | | | | 0.0
1297 0.4 0.4 0.003 O | | | | 0.0
1298 0.4 0.4 0.003 O | | | | 0.0
1299 0.4 0.4 0.003 O | | | | 0.0
1300 0.4 0.4 0.003 O | | | | 0.0
1310 0.4 0.4 0.003 O | | | | 0.0
1320 0.4 0.4 0.003 O | | | | 0.0
1330 0.4 0.4 0.003 O | | | | 0.0
1340 0.4 0.4 0.003 O | | | | 0.0
1350 0.3 0.3 0.002 O | | | | 0.0
1360 0.3 0.3 0.002 O | | | | 0.0
1370 0.3 0.3 0.002 O | | | | 0.0
1380 0.3 0.3 0.002 O | | | | 0.0
1390 0.3 0.3 0.002 O | | | | 0.0
1400 0.3 0.3 0.002 O | | | | 0.0
1420 0.3 0.3 0.002 O | | | | 0.0
1440 0.3 0.3 0.002 O | | | | 0.0
1460 0.2 0.2 0.001 O | | | | 0.0
1500 0.2 0.2 0.001 O | | | | 0.0
Remaining water in basin = 0.00 (Ac.Ft)
Peak flow out of basin = 39.61(CFS)
Peak flow time = 1156 Min., time interval # = 42
Maximum depth in basin = 2.66(Ft.)
Item #8. Page 1353
Meeting Date: 1/24/2023 / Packet Page #: 1418
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-86
Detention Subarea B Burned Capital Flood
CIVILCADD/CIVILDESIGN Engineering Software, (c) 1997-2004 Version 6.4 -------------------------------------------------------------------- Study Date : 03/07/18 Input hydrograph file name : prpbbu.hyd Output hydrograph file name: b50.hin
Program computation of outflow v. depth
************************************************************ CALCULATED OUTFLOW DATA AT DEPTH = 1.00(Ft.)
************************************************************ Weir capacity using equation Q = CLH^Exp(Using Feet as units) Weir Length = 3.00(Ft.) C value = 3.00 Exp = 1.50
Weir flow: Depth = H = 1.00(Ft.) Flow = 9.00 (CFS)
Total outflow at this depth = 9.00(CFS)
************************************************************ CALCULATED OUTFLOW DATA AT DEPTH = 2.00(Ft.)
************************************************************ Weir capacity using equation Q = CLH^Exp(Using Feet as units) Weir Length = 3.00(Ft.) C value = 3.00 Exp = 1.50
Weir flow: Depth = H = 2.00(Ft.) Flow = 25.46 (CFS)
Total outflow at this depth = 25.46(CFS)
************************************************************ CALCULATED OUTFLOW DATA AT DEPTH = 3.00(Ft.)
************************************************************ Weir capacity using equation Q = CLH^Exp(Using Feet as units) Weir Length = 3.00(Ft.) C value = 3.00 Exp = 1.50
Weir flow: Depth = H = 3.00(Ft.) Flow = 46.77 (CFS)
Total outflow at this depth = 46.77(CFS)
************************************************************ CALCULATED OUTFLOW DATA AT DEPTH = 4.00(Ft.)
************************************************************ Weir capacity using equation Q = CLH^Exp(Using Feet as units) Weir Length = 3.00(Ft.) C value = 3.00 Exp = 1.50
Weir flow: Depth = H = 4.00(Ft.) Flow = 72.00 (CFS)
Total outflow at this depth = 72.00(CFS)
************************************************************ CALCULATED OUTFLOW DATA AT DEPTH = 5.00(Ft.)
************************************************************ Weir capacity using equation Q = CLH^Exp(Using Feet as units) Weir Length = 3.00(Ft.) C value = 3.00 Exp = 1.50
Weir flow: Depth = H = 5.00(Ft.) Flow = 100.62 (CFS)
Total outflow at this depth = 100.62(CFS)
-------------------------------------------------------------------- Hydrograph time unit varies
Initial depth in storage basin = 0.00(Ft.)
-------------------------------------------------------------------- -------------------------------------------------------------------- Initial basin depth = 0.00 (Ft.)
Initial basin storage = 0.00 (Ac.Ft)
Initial basin outflow = 0.00 (CFS)
--------------------------------------------------------------------- Item #8. Page 1354
Meeting Date: 1/24/2023 / Packet Page #: 1419
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-87
-------------------------------------------------------------------- Depth vs. Storage and Depth vs. Discharge data @ 1 Min. Intervals:

Basin Depth Storage Outflow (S-O*dt/2) (S+O*dt/2)
(Ft.) (Ac.Ft) (CFS) (Ac.Ft) (Ac.Ft)
---------------------------------------------------------------------

0.000 0.000 0.000 0.000 0.000

1.000 0.060 9.000 0.054 0.066

2.000 0.150 25.456 0.132 0.168

3.000 0.300 46.765 0.268 0.332

4.000 0.500 72.000 0.450 0.550

5.000 0.750 100.623 0.681 0.819
-------------------------------------------------------------------- Hydrograph Detention Basin Routing
Hydrograph at 5 3 A Storm Day: 4 Drainage Area = 14.00
Total flood hydrograph volume this storm day = 3.93 Ac. Ft. --------------------------------------------------------------------- Graph values: 'I'= unit inflow; 'O'=outflow at time shown --------------------------------------------------------------------- Time Inflow Outflow Storage Depth
(Min) (CFS) (CFS) (Ac.Ft) .0 13.7 27.4 41.0 54.7 (Ft.)
0 0.0 0.0 0.000 O | | | | 0.0
100 0.7 0.7 0.004 O | | | | 0.1
200 0.7 0.7 0.005 O | | | | 0.1
300 0.7 0.7 0.005 O | | | | 0.1
400 0.8 0.8 0.005 O | | | | 0.1
500 0.8 0.8 0.005 O | | | | 0.1
600 0.9 0.9 0.006 O | | | | 0.1
700 1.0 1.0 0.007 O | | | | 0.1
800 1.2 1.2 0.008 O | | | | 0.1
900 1.7 1.7 0.011 O | | | | 0.2
1000 2.5 2.5 0.016 |O | | | | 0.3
1050 3.6 3.5 0.023 | O | | | | 0.4
1100 5.3 5.2 0.034 | O | | | | 0.6
1110 6.9 6.3 0.042 | OI | | | | 0.7
1120 8.4 7.8 0.052 | O | | | | 0.9
1130 10.2 9.5 0.063 | O | | | | 1.0
1131 10.4 9.7 0.064 | OI | | | | 1.0
1132 10.7 9.9 0.065 | OI | | | | 1.1
1133 11.0 10.2 0.066 | OI | | | | 1.1
1134 11.4 10.4 0.068 | O | | | | 1.1
1135 11.9 10.8 0.070 | O | | | | 1.1
1136 12.2 11.1 0.071 | OI| | | | 1.1
1137 12.8 11.5 0.074 | OI| | | | 1.2
1138 13.3 11.9 0.076 | OI| | | | 1.2
1139 13.8 12.3 0.078 | OI | | | 1.2
1140 14.3 12.8 0.081 | OI | | | 1.2
1141 15.0 13.3 0.083 | OI | | | 1.3
1142 15.6 13.8 0.086 | OI | | | 1.3
1143 16.3 14.3 0.089 | OI | | | 1.3
1144 17.1 15.0 0.093 | O I | | | 1.4
1145 18.3 15.7 0.097 | |OI | | | 1.4
1146 19.4 16.5 0.101 | |O I | | | 1.5
1147 20.6 17.4 0.106 | | O I | | | 1.5
1148 21.9 18.4 0.112 | | O I | | | 1.6
1149 26.1 20.2 0.121 | | O I| | | 1.7
1150 30.8 22.5 0.134 | | O | I | | 1.8
1151 36.9 25.7 0.152 | | O| I | | 2.0
1152 44.3 29.0 0.175 | | O |I | 2.2
1153 52.5 33.2 0.204 | | | O | I | 2.4
1154 54.7 37.0 0.231 | | | O | I 2.5
1155 53.6 40.0 0.252 | | | O| I| 2.7
1156 48.8 41.6 0.263 | | | O I | 2.8
1157 41.4 41.5 0.263 | | | O | 2.8
1158 32.7 40.0 0.252 | | | I O| | 2.7
1159 26.4 37.5 0.235 | | I| O | | 2.6
1160 21.4 34.7 0.215 | | I | O | | 2.4
1161 17.6 31.6 0.193 | | I | O | | 2.3
1162 14.8 28.6 0.172 | I O | | 2.1
1163 12.8 25.8 0.152 | I| O| | | 2.0
1164 11.4 22.7 0.135 | I | O | | | 1.8
1165 10.3 19.9 0.120 | I | O | | | 1.7
1166 9.5 17.6 0.107 | I | O | | | 1.5
1167 8.8 15.6 0.096 | I |O | | | 1.4
1168 8.2 14.0 0.087 | I O | | | 1.3
Item #8. Page 1355
Meeting Date: 1/24/2023 / Packet Page #: 1420
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-88
1169 7.7 12.6 0.079 | I O| | | | 1.2
1170 7.3 11.4 0.073 | I O | | | | 1.1
1171 7.0 10.4 0.068 | I O | | | | 1.1
1172 6.6 9.6 0.063 | I O | | | | 1.0
1173 6.3 8.9 0.059 | I O | | | | 1.0
1174 6.1 8.3 0.056 | IO | | | | 0.9
1175 5.9 7.9 0.053 | IO | | | | 0.9
1176 5.6 7.5 0.050 | IO | | | | 0.8
1177 5.4 7.1 0.047 | IO | | | | 0.8
1178 5.2 6.7 0.045 | O | | | | 0.7
1179 5.0 6.4 0.043 | IO | | | | 0.7
1180 4.9 6.1 0.041 | IO | | | | 0.7
1181 4.7 5.9 0.039 | IO | | | | 0.7
1182 4.6 5.6 0.037 | IO | | | | 0.6
1183 4.4 5.4 0.036 | IO | | | | 0.6
1184 4.3 5.2 0.035 | IO | | | | 0.6
1185 4.2 5.0 0.033 | O | | | | 0.6
1186 4.0 4.8 0.032 | O | | | | 0.5
1187 4.0 4.7 0.031 | O | | | | 0.5
1188 3.8 4.5 0.030 | O | | | | 0.5
1189 3.7 4.3 0.029 | O | | | | 0.5
1190 3.6 4.2 0.028 | O | | | | 0.5
1191 3.6 4.1 0.027 | O | | | | 0.5
1192 3.4 4.0 0.026 |IO | | | | 0.4
1193 3.4 3.9 0.026 |IO | | | | 0.4
1194 3.3 3.8 0.025 |IO | | | | 0.4
1195 3.3 3.7 0.024 |IO | | | | 0.4
1196 3.2 3.6 0.024 |IO | | | | 0.4
1197 3.1 3.5 0.023 |IO | | | | 0.4
1198 3.0 3.4 0.023 |O | | | | 0.4
1199 3.0 3.3 0.022 |O | | | | 0.4
1200 3.0 3.3 0.022 |O | | | | 0.4
1201 2.9 3.2 0.021 |O | | | | 0.4
1202 2.8 3.1 0.021 |O | | | | 0.3
1203 2.8 3.1 0.020 |O | | | | 0.3
1204 2.7 3.0 0.020 |O | | | | 0.3
1205 2.7 2.9 0.020 |O | | | | 0.3
1206 2.6 2.9 0.019 |O | | | | 0.3
1207 2.6 2.8 0.019 |O | | | | 0.3
1208 2.5 2.8 0.018 |O | | | | 0.3
1209 2.5 2.7 0.018 |O | | | | 0.3
1210 2.5 2.7 0.018 |O | | | | 0.3
1211 2.4 2.6 0.017 |O | | | | 0.3
1212 2.4 2.6 0.017 |O | | | | 0.3
1213 2.4 2.5 0.017 |O | | | | 0.3
1214 2.3 2.5 0.017 |O | | | | 0.3
1215 2.3 2.5 0.016 |O | | | | 0.3
1216 2.2 2.4 0.016 |O | | | | 0.3
1217 2.2 2.4 0.016 |O | | | | 0.3
1218 2.1 2.3 0.015 |O | | | | 0.3
1219 2.2 2.3 0.015 |O | | | | 0.3
1220 2.1 2.3 0.015 |O | | | | 0.3
1221 2.1 2.2 0.015 |O | | | | 0.2
1222 2.1 2.2 0.015 |O | | | | 0.2
1223 2.0 2.2 0.014 |O | | | | 0.2
1224 2.0 2.1 0.014 |O | | | | 0.2
1225 2.0 2.1 0.014 |O | | | | 0.2
1226 1.9 2.1 0.014 |O | | | | 0.2
1227 1.9 2.0 0.014 |O | | | | 0.2
1228 1.9 2.0 0.013 |O | | | | 0.2
1229 1.8 2.0 0.013 |O | | | | 0.2
1230 1.8 1.9 0.013 |O | | | | 0.2
1231 1.8 1.9 0.013 |O | | | | 0.2
1232 1.8 1.9 0.013 |O | | | | 0.2
1233 1.8 1.9 0.013 |O | | | | 0.2
1234 1.7 1.8 0.012 IO | | | | 0.2
1235 1.7 1.8 0.012 IO | | | | 0.2
1236 1.7 1.8 0.012 IO | | | | 0.2
1237 1.6 1.8 0.012 IO | | | | 0.2
1238 1.6 1.7 0.012 IO | | | | 0.2
1239 1.6 1.7 0.011 O | | | | 0.2
1240 1.6 1.7 0.011 O | | | | 0.2
1241 1.6 1.7 0.011 O | | | | 0.2
1242 1.5 1.6 0.011 O | | | | 0.2
1243 1.5 1.6 0.011 O | | | | 0.2
1244 1.5 1.6 0.011 O | | | | 0.2
Item #8. Page 1356
Meeting Date: 1/24/2023 / Packet Page #: 1421
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-89
1245 1.5 1.6 0.010 O | | | | 0.2
1246 1.4 1.5 0.010 O | | | | 0.2
1247 1.4 1.5 0.010 O | | | | 0.2
1248 1.5 1.5 0.010 O | | | | 0.2
1249 1.4 1.5 0.010 O | | | | 0.2
1250 1.4 1.5 0.010 O | | | | 0.2
1251 1.4 1.5 0.010 O | | | | 0.2
1252 1.4 1.4 0.010 O | | | | 0.2
1253 1.3 1.4 0.009 O | | | | 0.2
1254 1.3 1.4 0.009 O | | | | 0.2
1255 1.3 1.4 0.009 O | | | | 0.2
1256 1.3 1.4 0.009 O | | | | 0.2
1257 1.3 1.4 0.009 O | | | | 0.2
1258 1.2 1.3 0.009 O | | | | 0.1
1259 1.2 1.3 0.009 O | | | | 0.1
1260 1.2 1.3 0.009 O | | | | 0.1
1261 1.2 1.3 0.008 O | | | | 0.1
1262 1.2 1.3 0.008 O | | | | 0.1
1263 1.2 1.2 0.008 O | | | | 0.1
1264 1.1 1.2 0.008 O | | | | 0.1
1265 1.1 1.2 0.008 O | | | | 0.1
1266 1.1 1.2 0.008 O | | | | 0.1
1267 1.1 1.2 0.008 O | | | | 0.1
1268 1.1 1.2 0.008 O | | | | 0.1
1269 1.1 1.1 0.008 O | | | | 0.1
1270 1.1 1.1 0.008 O | | | | 0.1
1271 1.1 1.1 0.008 O | | | | 0.1
1272 1.1 1.1 0.007 O | | | | 0.1
1273 1.1 1.1 0.007 O | | | | 0.1
1274 1.1 1.1 0.007 O | | | | 0.1
1275 1.0 1.1 0.007 O | | | | 0.1
1276 1.0 1.1 0.007 O | | | | 0.1
1277 1.0 1.1 0.007 O | | | | 0.1
1278 1.0 1.1 0.007 O | | | | 0.1
1279 1.0 1.0 0.007 O | | | | 0.1
1280 1.0 1.0 0.007 O | | | | 0.1
1281 1.0 1.0 0.007 O | | | | 0.1
1282 1.0 1.0 0.007 O | | | | 0.1
1283 1.0 1.0 0.007 O | | | | 0.1
1284 1.0 1.0 0.007 O | | | | 0.1
1285 1.0 1.0 0.007 O | | | | 0.1
1286 1.0 1.0 0.007 O | | | | 0.1
1287 1.0 1.0 0.007 O | | | | 0.1
1288 1.0 1.0 0.007 O | | | | 0.1
1289 1.0 1.0 0.007 O | | | | 0.1
1290 1.0 1.0 0.007 O | | | | 0.1
1291 1.0 1.0 0.007 O | | | | 0.1
1292 1.0 1.0 0.007 O | | | | 0.1
1293 1.0 1.0 0.007 O | | | | 0.1
1294 0.9 1.0 0.007 O | | | | 0.1
1295 0.9 1.0 0.006 O | | | | 0.1
1296 0.9 1.0 0.006 O | | | | 0.1
1297 0.9 0.9 0.006 O | | | | 0.1
1298 0.9 0.9 0.006 O | | | | 0.1
1299 0.9 0.9 0.006 O | | | | 0.1
1300 0.9 0.9 0.006 O | | | | 0.1
1310 0.9 0.9 0.006 O | | | | 0.1
1320 0.9 0.9 0.006 O | | | | 0.1
1330 0.8 0.8 0.006 O | | | | 0.1
1340 0.8 0.8 0.005 O | | | | 0.1
1350 0.8 0.8 0.005 O | | | | 0.1
1360 0.8 0.8 0.005 O | | | | 0.1
1370 0.8 0.8 0.005 O | | | | 0.1
1380 0.7 0.7 0.005 O | | | | 0.1
1390 0.7 0.7 0.005 O | | | | 0.1
1400 0.7 0.7 0.005 O | | | | 0.1
1420 0.7 0.7 0.005 O | | | | 0.1
1440 0.7 0.7 0.005 O | | | | 0.1
1460 0.4 0.5 0.003 O | | | | 0.1
1500 0.4 0.3 0.002 O | | | | 0.0
Remaining water in basin = 0.00 (Ac.Ft)
Peak flow out of basin = 41.55(CFS)
Peak flow time = 1156 Min., time interval # = 42
Maximum depth in basin = 2.76(Ft.)
Item #8. Page 1357
Meeting Date: 1/24/2023 / Packet Page #: 1422
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-90
Detention Subareas C, F, & H Clear Water Urban Flood
CIVILCADD/CIVILDESIGN Engineering Software, (c) 1997-2009 Version 6.5 -------------------------------------------------------------------- Study Date : 08/01/18 Input hydrograph file name : prpc25.hyd Output hydrograph file name: c25.hin
Program computation of outflow v. depth
************************************************************ CALCULATED OUTFLOW DATA AT DEPTH = 1.00(Ft.)
************************************************************ Weir capacity using equation Q = CLH^Exp(Using Feet as units) Weir Length = 3.00(Ft.) C value = 3.00 Exp = 1.50
Weir flow: Depth = H = 1.00(Ft.) Flow = 9.00 (CFS)
Total outflow at this depth = 9.00(CFS)
************************************************************ CALCULATED OUTFLOW DATA AT DEPTH = 2.00(Ft.)
************************************************************ Weir capacity using equation Q = CLH^Exp(Using Feet as units) Weir Length = 3.00(Ft.) C value = 3.00 Exp = 1.50
Weir flow: Depth = H = 2.00(Ft.) Flow = 25.46 (CFS)
Weir capacity using equation Q = CLH^Exp(Using Feet as units) Weir Length = 10.00(Ft.) C value = 3.00 Exp = 1.50
Weir flow: Depth = H = 0.50(Ft.) Flow = 10.61 (CFS)
Total outflow at this depth = 36.06(CFS)
-------------------------------------------------------------------- Hydrograph time unit varies
Initial depth in storage basin = 0.00(Ft.)
-------------------------------------------------------------------- -------------------------------------------------------------------- Initial basin depth = 0.00 (Ft.)
Initial basin storage = 0.00 (Ac.Ft)
Initial basin outflow = 0.00 (CFS)
--------------------------------------------------------------------- -------------------------------------------------------------------- Depth vs. Storage and Depth vs. Discharge data @ 1 Min. Intervals:

Basin Depth Storage Outflow (S-O*dt/2) (S+O*dt/2)
(Ft.) (Ac.Ft) (CFS) (Ac.Ft) (Ac.Ft)
---------------------------------------------------------------------

0.000 0.000 0.000 0.000 0.000

1.000 0.080 9.000 0.074 0.086

2.000 0.190 36.062 0.165 0.215
-------------------------------------------------------------- Hydrograph Detention Basin Routing
Hydrograph at 5 3 A Storm Day: 4 Drainage Area = 9.00
Total flood hydrograph volume this storm day = 1.44 Ac. Ft. --------------------------------------------------------------------- Graph values: 'I'= unit inflow; 'O'=outflow at time shown --------------------------------------------------------------------- Time Inflow Outflow Storage Depth
(Min) (CFS) (CFS) (Ac.Ft) .0 8.7 17.4 26.2 34.9 (Ft.)
0 0.0 0.0 0.000 O | | | | 0.0
100 0.2 0.2 0.002 O | | | | 0.0
200 0.2 0.2 0.002 O | | | | 0.0
300 0.2 0.2 0.002 O | | | | 0.0
400 0.2 0.2 0.002 O | | | | 0.0
500 0.2 0.2 0.002 O | | | | 0.0
600 0.2 0.2 0.002 O | | | | 0.0
700 0.2 0.2 0.002 O | | | | 0.0
Item #8. Page 1358
Meeting Date: 1/24/2023 / Packet Page #: 1423
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-91
800 0.3 0.3 0.003 O | | | | 0.0
900 0.4 0.4 0.004 O | | | | 0.0
1000 0.8 0.8 0.007 O | | | | 0.1
1050 1.4 1.3 0.012 |O | | | | 0.1
1100 2.3 2.2 0.019 | O | | | | 0.2
1110 3.4 2.9 0.025 | OI | | | | 0.3
1120 3.9 3.6 0.032 | O | | | | 0.4
1130 5.0 4.4 0.039 | O | | | | 0.5
1131 5.1 4.5 0.040 | O | | | | 0.5
1132 5.3 4.6 0.041 | O | | | | 0.5
1133 5.6 4.8 0.042 | OI | | | | 0.5
1134 5.9 4.9 0.044 | OI | | | | 0.5
1135 6.2 5.1 0.045 | OI | | | | 0.6
1136 6.3 5.3 0.047 | OI | | | | 0.6
1137 6.7 5.5 0.049 | OI | | | | 0.6
1138 7.0 5.7 0.051 | OI | | | | 0.6
1139 7.2 5.9 0.053 | OI | | | | 0.7
1140 7.4 6.1 0.055 | OI | | | | 0.7
1141 8.1 6.4 0.057 | O I| | | | 0.7
1142 8.5 6.7 0.060 | OI| | | | 0.7
1143 8.8 7.0 0.062 | O I | | | 0.8
1144 9.2 7.3 0.065 | O I | | | 0.8
1145 10.3 7.8 0.069 | O|I | | | 0.9
1146 11.0 8.2 0.073 | O| I | | | 0.9
1147 11.7 8.7 0.078 | O| I | | | 1.0
1148 12.4 9.5 0.082 | O I | | | 1.0
1149 17.3 11.8 0.091 | | O I| | | 1.1
1150 21.7 14.6 0.103 | | O | I | | 1.2
1151 26.0 17.9 0.116 | | O I| | 1.3
1152 30.4 21.5 0.131 | | | O | I | 1.5
1153 34.9 25.4 0.147 | | | O| I 1.6
1154 30.5 26.9 0.153 | | | O I | 1.7
1155 25.3 26.4 0.151 | | | IO | 1.6
1156 19.8 24.5 0.143 | | | I O | | 1.6
1157 14.1 21.5 0.131 | | I | O | | 1.5
1158 8.5 17.7 0.115 | I| O | | 1.3
1159 6.8 14.6 0.103 | I | O | | | 1.2
1160 5.8 12.0 0.092 | I | O | | | 1.1
1161 5.2 10.0 0.084 | I |O | | | 1.0
1162 4.7 8.8 0.078 | I O | | | 1.0
1163 4.3 8.1 0.072 | I O| | | | 0.9
1164 4.0 7.5 0.067 | I O | | | | 0.8
1165 3.7 7.0 0.062 | I O | | | | 0.8
1166 3.4 6.5 0.057 | I O | | | | 0.7
1167 3.2 6.0 0.053 | I O | | | | 0.7
1168 3.0 5.6 0.049 | I O | | | | 0.6
1169 2.8 5.2 0.046 | I O | | | | 0.6
1170 2.7 4.8 0.043 | I O | | | | 0.5
1171 2.6 4.5 0.040 | I O | | | | 0.5
1172 2.4 4.2 0.037 | IO | | | | 0.5
1173 2.3 3.9 0.035 | IO | | | | 0.4
1174 2.2 3.7 0.033 | IO | | | | 0.4
1175 2.1 3.4 0.031 |I O | | | | 0.4
1176 2.0 3.2 0.029 |IO | | | | 0.4
1177 1.9 3.0 0.027 |IO | | | | 0.3
1178 1.9 2.9 0.026 |IO | | | | 0.3
1179 1.7 2.7 0.024 |IO | | | | 0.3
1180 1.6 2.6 0.023 |IO | | | | 0.3
1181 1.6 2.4 0.021 |IO | | | | 0.3
1182 1.6 2.3 0.020 |IO | | | | 0.3
1183 1.5 2.2 0.019 |IO | | | | 0.2
1184 1.4 2.1 0.018 |O | | | | 0.2
1185 1.4 2.0 0.018 |O | | | | 0.2
1186 1.3 1.9 0.017 |O | | | | 0.2
1187 1.3 1.8 0.016 |O | | | | 0.2
1188 1.3 1.7 0.015 |O | | | | 0.2
1189 1.3 1.7 0.015 |O | | | | 0.2
1190 1.2 1.6 0.014 |O | | | | 0.2
1191 1.2 1.5 0.014 |O | | | | 0.2
1192 1.1 1.5 0.013 |O | | | | 0.2
1193 1.1 1.4 0.013 |O | | | | 0.2
1194 1.1 1.4 0.012 |O | | | | 0.2
1195 1.1 1.3 0.012 |O | | | | 0.1
1196 1.1 1.3 0.012 |O | | | | 0.1
1197 1.0 1.3 0.011 IO | | | | 0.1
1198 0.9 1.2 0.011 IO | | | | 0.1
Item #8. Page 1359
Meeting Date: 1/24/2023 / Packet Page #: 1424
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-92
1199 0.9 1.2 0.010 IO | | | | 0.1
1200 0.9 1.1 0.010 IO | | | | 0.1
1201 0.9 1.1 0.010 IO | | | | 0.1
1202 0.9 1.1 0.009 O | | | | 0.1
1203 0.9 1.0 0.009 O | | | | 0.1
1204 0.8 1.0 0.009 O | | | | 0.1
1205 0.8 1.0 0.009 O | | | | 0.1
1206 0.8 1.0 0.008 O | | | | 0.1
1207 0.8 0.9 0.008 O | | | | 0.1
1208 0.7 0.9 0.008 O | | | | 0.1
1209 0.7 0.9 0.008 O | | | | 0.1
1210 0.7 0.8 0.008 O | | | | 0.1
1211 0.7 0.8 0.007 O | | | | 0.1
1212 0.7 0.8 0.007 O | | | | 0.1
1213 0.7 0.8 0.007 O | | | | 0.1
1214 0.6 0.8 0.007 O | | | | 0.1
1215 0.6 0.7 0.007 O | | | | 0.1
1216 0.6 0.7 0.006 O | | | | 0.1
1217 0.5 0.7 0.006 O | | | | 0.1
1218 0.5 0.7 0.006 O | | | | 0.1
1219 0.6 0.7 0.006 O | | | | 0.1
1220 0.5 0.6 0.006 O | | | | 0.1
1221 0.5 0.6 0.005 O | | | | 0.1
1222 0.5 0.6 0.005 O | | | | 0.1
1223 0.5 0.6 0.005 O | | | | 0.1
1224 0.5 0.6 0.005 O | | | | 0.1
1225 0.5 0.6 0.005 O | | | | 0.1
1226 0.5 0.6 0.005 O | | | | 0.1
1227 0.4 0.5 0.005 O | | | | 0.1
1228 0.4 0.5 0.005 O | | | | 0.1
1229 0.4 0.5 0.004 O | | | | 0.1
1230 0.4 0.5 0.004 O | | | | 0.1
1231 0.3 0.5 0.004 O | | | | 0.1
1232 0.4 0.4 0.004 O | | | | 0.0
1233 0.4 0.4 0.004 O | | | | 0.0
1234 0.3 0.4 0.004 O | | | | 0.0
1235 0.3 0.4 0.004 O | | | | 0.0
1236 0.3 0.4 0.003 O | | | | 0.0
1237 0.3 0.4 0.003 O | | | | 0.0
1238 0.3 0.4 0.003 O | | | | 0.0
1239 0.3 0.4 0.003 O | | | | 0.0
1240 0.3 0.3 0.003 O | | | | 0.0
1241 0.3 0.3 0.003 O | | | | 0.0
1242 0.3 0.3 0.003 O | | | | 0.0
1243 0.3 0.3 0.003 O | | | | 0.0
1244 0.3 0.3 0.003 O | | | | 0.0
1245 0.3 0.3 0.003 O | | | | 0.0
1246 0.3 0.3 0.003 O | | | | 0.0
1247 0.3 0.3 0.003 O | | | | 0.0
1248 0.3 0.3 0.003 O | | | | 0.0
1249 0.3 0.3 0.003 O | | | | 0.0
1250 0.3 0.3 0.003 O | | | | 0.0
1251 0.3 0.3 0.003 O | | | | 0.0
1252 0.3 0.3 0.003 O | | | | 0.0
1253 0.3 0.3 0.003 O | | | | 0.0
1254 0.3 0.3 0.003 O | | | | 0.0
1255 0.3 0.3 0.003 O | | | | 0.0
1256 0.3 0.3 0.003 O | | | | 0.0
1257 0.3 0.3 0.003 O | | | | 0.0
1258 0.3 0.3 0.003 O | | | | 0.0
1259 0.3 0.3 0.003 O | | | | 0.0
1260 0.3 0.3 0.003 O | | | | 0.0
1261 0.3 0.3 0.003 O | | | | 0.0
1262 0.3 0.3 0.003 O | | | | 0.0
1263 0.3 0.3 0.003 O | | | | 0.0
1264 0.3 0.3 0.003 O | | | | 0.0
1265 0.3 0.3 0.003 O | | | | 0.0
1266 0.3 0.3 0.003 O | | | | 0.0
1267 0.3 0.3 0.003 O | | | | 0.0
1268 0.3 0.3 0.003 O | | | | 0.0
1269 0.3 0.3 0.003 O | | | | 0.0
1270 0.3 0.3 0.003 O | | | | 0.0
1271 0.3 0.3 0.003 O | | | | 0.0
1272 0.2 0.3 0.003 O | | | | 0.0
1273 0.2 0.3 0.002 O | | | | 0.0
1274 0.3 0.3 0.002 O | | | | 0.0
Item #8. Page 1360
Meeting Date: 1/24/2023 / Packet Page #: 1425
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-93
1275 0.2 0.3 0.002 O | | | | 0.0
1276 0.2 0.3 0.002 O | | | | 0.0
1277 0.2 0.2 0.002 O | | | | 0.0
1278 0.2 0.2 0.002 O | | | | 0.0
1279 0.2 0.2 0.002 O | | | | 0.0
1280 0.2 0.2 0.002 O | | | | 0.0
1281 0.2 0.2 0.002 O | | | | 0.0
1282 0.2 0.2 0.002 O | | | | 0.0
1283 0.2 0.2 0.002 O | | | | 0.0
1284 0.2 0.2 0.002 O | | | | 0.0
1285 0.2 0.2 0.002 O | | | | 0.0
1286 0.2 0.2 0.002 O | | | | 0.0
1287 0.2 0.2 0.002 O | | | | 0.0
1288 0.2 0.2 0.002 O | | | | 0.0
1289 0.2 0.2 0.002 O | | | | 0.0
1290 0.2 0.2 0.002 O | | | | 0.0
1291 0.2 0.2 0.002 O | | | | 0.0
1292 0.2 0.2 0.002 O | | | | 0.0
1293 0.2 0.2 0.002 O | | | | 0.0
1294 0.2 0.2 0.002 O | | | | 0.0
1295 0.2 0.2 0.002 O | | | | 0.0
1296 0.2 0.2 0.002 O | | | | 0.0
1297 0.2 0.2 0.002 O | | | | 0.0
1298 0.2 0.2 0.002 O | | | | 0.0
1299 0.2 0.2 0.002 O | | | | 0.0
1300 0.2 0.2 0.002 O | | | | 0.0
1310 0.2 0.2 0.002 O | | | | 0.0
1320 0.2 0.2 0.002 O | | | | 0.0
1330 0.2 0.2 0.002 O | | | | 0.0
1340 0.2 0.2 0.002 O | | | | 0.0
1350 0.2 0.2 0.002 O | | | | 0.0
1360 0.2 0.2 0.002 O | | | | 0.0
1370 0.2 0.2 0.002 O | | | | 0.0
1380 0.2 0.2 0.002 O | | | | 0.0
1390 0.2 0.2 0.002 O | | | | 0.0
1400 0.2 0.2 0.002 O | | | | 0.0
1420 0.2 0.2 0.002 O | | | | 0.0
1440 0.2 0.2 0.002 O | | | | 0.0
1460 0.0 0.1 0.001 O | | | | 0.0
1500 0.0 0.0 0.000 O | | | | 0.0
Remaining water in basin = 0.00 (Ac.Ft)
Peak flow out of basin = 26.89(CFS)
Peak flow time = 1154 Min., time interval # = 40
Maximum depth in basin = 1.66(Ft.)
Item #8. Page 1361
Meeting Date: 1/24/2023 / Packet Page #: 1426
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-94
Detention Subareas C, F, & H Clear Water Capital Flood
CIVILCADD/CIVILDESIGN Engineering Software, (c) 1997-2009 Version 6.5 -------------------------------------------------------------------- Study Date : 08/01/18 Input hydrograph file name : prpc50.hyd Output hydrograph file name: c50.hin
Program computation of outflow v. depth
************************************************************ CALCULATED OUTFLOW DATA AT DEPTH = 1.00(Ft.)
************************************************************ Weir capacity using equation Q = CLH^Exp(Using Feet as units) Weir Length = 3.00(Ft.) C value = 3.00 Exp = 1.50
Weir flow: Depth = H = 1.00(Ft.) Flow = 9.00 (CFS)
Total outflow at this depth = 9.00(CFS)
************************************************************ CALCULATED OUTFLOW DATA AT DEPTH = 2.00(Ft.)
************************************************************ Weir capacity using equation Q = CLH^Exp(Using Feet as units) Weir Length = 3.00(Ft.) C value = 3.00 Exp = 1.50
Weir flow: Depth = H = 2.00(Ft.) Flow = 25.46 (CFS)
Weir capacity using equation Q = CLH^Exp(Using Feet as units) Weir Length = 10.00(Ft.) C value = 3.00 Exp = 1.50
Weir flow: Depth = H = 0.50(Ft.) Flow = 10.61 (CFS)
Total outflow at this depth = 36.06(CFS)
-------------------------------------------------------------------- Hydrograph time unit varies
Initial depth in storage basin = 0.00(Ft.)
-------------------------------------------------------------------- -------------------------------------------------------------------- Initial basin depth = 0.00 (Ft.)
Initial basin storage = 0.00 (Ac.Ft)
Initial basin outflow = 0.00 (CFS)
--------------------------------------------------------------------- -------------------------------------------------------------------- Depth vs. Storage and Depth vs. Discharge data @ 1 Min. Intervals:

Basin Depth Storage Outflow (S-O*dt/2) (S+O*dt/2)
(Ft.) (Ac.Ft) (CFS) (Ac.Ft) (Ac.Ft)
---------------------------------------------------------------------

0.000 0.000 0.000 0.000 0.000

1.000 0.080 9.000 0.074 0.086

2.000 0.190 36.062 0.165 0.215
-------------------------------------------------------------------- Hydrograph Detention Basin Routing
Hydrograph at 5 3 A Storm Day: 4 Drainage Area = 9.00
Total flood hydrograph volume this storm day = 1.76 Ac. Ft. --------------------------------------------------------------------- Graph values: 'I'= unit inflow; 'O'=outflow at time shown --------------------------------------------------------------------- Time Inflow Outflow Storage Depth
(Min) (CFS) (CFS) (Ac.Ft) .0 10.1 20.2 30.3 40.4 (Ft.)
0 0.0 0.0 0.000 O | | | | 0.0
100 0.2 0.2 0.002 O | | | | 0.0
200 0.2 0.2 0.002 O | | | | 0.0
300 0.2 0.2 0.002 O | | | | 0.0
400 0.2 0.2 0.002 O | | | | 0.0
Item #8. Page 1362
Meeting Date: 1/24/2023 / Packet Page #: 1427
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-95
500 0.2 0.2 0.002 O | | | | 0.0
600 0.2 0.2 0.002 O | | | | 0.0
700 0.3 0.3 0.003 O | | | | 0.0
800 0.4 0.4 0.004 O | | | | 0.0
900 0.7 0.7 0.006 O | | | | 0.1
1000 1.1 1.1 0.010 O | | | | 0.1
1050 1.8 1.7 0.015 |O | | | | 0.2
1100 2.9 2.8 0.025 | O | | | | 0.3
1110 4.1 3.5 0.031 | OI | | | | 0.4
1120 4.8 4.3 0.039 | O | | | | 0.5
1130 6.0 5.3 0.047 | O | | | | 0.6
1131 6.2 5.5 0.049 | O | | | | 0.6
1132 6.4 5.6 0.050 | OI | | | | 0.6
1133 6.7 5.8 0.051 | OI | | | | 0.6
1134 7.1 6.0 0.053 | OI | | | | 0.7
1135 7.5 6.2 0.055 | OI | | | | 0.7
1136 7.6 6.4 0.057 | OI | | | | 0.7
1137 8.1 6.6 0.059 | OI | | | | 0.7
1138 8.4 6.9 0.061 | OI | | | | 0.8
1139 8.6 7.1 0.063 | OI | | | | 0.8
1140 8.9 7.4 0.066 | O I| | | | 0.8
1141 9.6 7.7 0.068 | OI| | | | 0.9
1142 10.0 8.0 0.071 | OI| | | | 0.9
1143 10.5 8.4 0.075 | O I | | | 0.9
1144 11.0 8.8 0.078 | O I | | | 1.0
1145 12.2 9.5 0.082 | O|I | | | 1.0
1146 13.0 10.5 0.086 | O I | | | 1.1
1147 13.8 11.5 0.090 | |OI | | | 1.1
1148 14.6 12.4 0.094 | |O I | | | 1.1
1149 20.3 14.7 0.103 | | O I | | 1.2
1150 25.3 17.8 0.116 | | O | I | | 1.3
1151 30.2 21.4 0.130 | | O I| | 1.5
1152 35.3 25.4 0.147 | | | O | I | 1.6
1153 40.4 29.7 0.164 | | | O| I 1.8
1154 35.4 31.4 0.171 | | | O I | 1.8
1155 29.5 30.8 0.169 | | | IO | 1.8
1156 23.2 28.6 0.160 | | | I O | | 1.7
1157 16.6 25.1 0.146 | | I | O | | 1.6
1158 10.0 20.8 0.128 | I| O | | 1.4
1159 8.2 17.1 0.113 | I | O | | | 1.3
1160 7.0 14.2 0.101 | I | O | | | 1.2
1161 6.3 11.9 0.092 | I |O | | | 1.1
1162 5.6 10.1 0.084 | I O| | | | 1.0
1163 5.2 8.8 0.079 | I O | | | | 1.0
1164 4.8 8.3 0.073 | I O | | | | 0.9
1165 4.5 7.7 0.069 | I O | | | | 0.9
1166 4.1 7.2 0.064 | I O | | | | 0.8
1167 3.9 6.7 0.060 | I O | | | | 0.7
1168 3.7 6.3 0.056 | I O | | | | 0.7
1169 3.5 5.9 0.052 | I O | | | | 0.7
1170 3.3 5.5 0.049 | I O | | | | 0.6
1171 3.2 5.2 0.046 | I O | | | | 0.6
1172 3.0 4.9 0.043 | IO | | | | 0.5
1173 2.9 4.6 0.041 | IO | | | | 0.5
1174 2.8 4.3 0.038 | IO | | | | 0.5
1175 2.7 4.1 0.036 | IO | | | | 0.5
1176 2.5 3.9 0.034 |I O | | | | 0.4
1177 2.4 3.7 0.032 |IO | | | | 0.4
1178 2.4 3.5 0.031 |IO | | | | 0.4
1179 2.3 3.3 0.029 |IO | | | | 0.4
1180 2.2 3.1 0.028 |IO | | | | 0.3
1181 2.2 3.0 0.027 |IO | | | | 0.3
1182 2.1 2.9 0.026 |IO | | | | 0.3
1183 2.0 2.8 0.024 |IO | | | | 0.3
1184 1.9 2.6 0.023 |IO | | | | 0.3
1185 1.9 2.5 0.022 |O | | | | 0.3
1186 1.7 2.4 0.021 |O | | | | 0.3
1187 1.7 2.3 0.020 |O | | | | 0.3
1188 1.6 2.2 0.020 |O | | | | 0.2
1189 1.6 2.1 0.019 |O | | | | 0.2
1190 1.6 2.0 0.018 |O | | | | 0.2
1191 1.6 2.0 0.018 |O | | | | 0.2
1192 1.5 1.9 0.017 |O | | | | 0.2
1193 1.5 1.9 0.016 |O | | | | 0.2
1194 1.5 1.8 0.016 |O | | | | 0.2
1195 1.4 1.7 0.015 |O | | | | 0.2
Item #8. Page 1363
Meeting Date: 1/24/2023 / Packet Page #: 1428
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-96
1196 1.4 1.7 0.015 |O | | | | 0.2
1197 1.3 1.6 0.015 |O | | | | 0.2
1198 1.3 1.6 0.014 |O | | | | 0.2
1199 1.3 1.5 0.014 |O | | | | 0.2
1200 1.3 1.5 0.013 |O | | | | 0.2
1201 1.2 1.5 0.013 IO | | | | 0.2
1202 1.2 1.4 0.013 IO | | | | 0.2
1203 1.2 1.4 0.012 IO | | | | 0.2
1204 1.1 1.4 0.012 IO | | | | 0.2
1205 1.1 1.3 0.012 IO | | | | 0.1
1206 1.1 1.3 0.011 IO | | | | 0.1
1207 1.1 1.3 0.011 O | | | | 0.1
1208 1.0 1.2 0.011 O | | | | 0.1
1209 1.0 1.2 0.011 O | | | | 0.1
1210 1.0 1.2 0.010 O | | | | 0.1
1211 1.0 1.1 0.010 O | | | | 0.1
1212 1.0 1.1 0.010 O | | | | 0.1
1213 1.0 1.1 0.010 O | | | | 0.1
1214 0.9 1.1 0.010 O | | | | 0.1
1215 0.9 1.0 0.009 O | | | | 0.1
1216 0.9 1.0 0.009 O | | | | 0.1
1217 0.8 1.0 0.009 O | | | | 0.1
1218 0.8 1.0 0.009 O | | | | 0.1
1219 0.9 1.0 0.009 O | | | | 0.1
1220 0.8 0.9 0.008 O | | | | 0.1
1221 0.8 0.9 0.008 O | | | | 0.1
1222 0.8 0.9 0.008 O | | | | 0.1
1223 0.8 0.9 0.008 O | | | | 0.1
1224 0.7 0.9 0.008 O | | | | 0.1
1225 0.7 0.8 0.007 O | | | | 0.1
1226 0.7 0.8 0.007 O | | | | 0.1
1227 0.7 0.8 0.007 O | | | | 0.1
1228 0.7 0.8 0.007 O | | | | 0.1
1229 0.7 0.8 0.007 O | | | | 0.1
1230 0.7 0.8 0.007 O | | | | 0.1
1231 0.6 0.7 0.007 O | | | | 0.1
1232 0.7 0.7 0.007 O | | | | 0.1
1233 0.7 0.7 0.006 O | | | | 0.1
1234 0.6 0.7 0.006 O | | | | 0.1
1235 0.6 0.7 0.006 O | | | | 0.1
1236 0.6 0.7 0.006 O | | | | 0.1
1237 0.6 0.7 0.006 O | | | | 0.1
1238 0.5 0.6 0.006 O | | | | 0.1
1239 0.6 0.6 0.006 O | | | | 0.1
1240 0.5 0.6 0.005 O | | | | 0.1
1241 0.6 0.6 0.005 O | | | | 0.1
1242 0.5 0.6 0.005 O | | | | 0.1
1243 0.5 0.6 0.005 O | | | | 0.1
1244 0.5 0.6 0.005 O | | | | 0.1
1245 0.5 0.6 0.005 O | | | | 0.1
1246 0.4 0.5 0.005 O | | | | 0.1
1247 0.4 0.5 0.005 O | | | | 0.1
1248 0.5 0.5 0.005 O | | | | 0.1
1249 0.4 0.5 0.004 O | | | | 0.1
1250 0.4 0.5 0.004 O | | | | 0.1
1251 0.4 0.5 0.004 O | | | | 0.1
1252 0.4 0.5 0.004 O | | | | 0.1
1253 0.4 0.5 0.004 O | | | | 0.1
1254 0.4 0.4 0.004 O | | | | 0.0
1255 0.4 0.4 0.004 O | | | | 0.0
1256 0.4 0.4 0.004 O | | | | 0.0
1257 0.4 0.4 0.004 O | | | | 0.0
1258 0.4 0.4 0.004 O | | | | 0.0
1259 0.4 0.4 0.004 O | | | | 0.0
1260 0.4 0.4 0.004 O | | | | 0.0
1261 0.4 0.4 0.004 O | | | | 0.0
1262 0.4 0.4 0.004 O | | | | 0.0
1263 0.4 0.4 0.004 O | | | | 0.0
1264 0.3 0.4 0.004 O | | | | 0.0
1265 0.3 0.4 0.003 O | | | | 0.0
1266 0.3 0.4 0.003 O | | | | 0.0
1267 0.3 0.4 0.003 O | | | | 0.0
1268 0.3 0.4 0.003 O | | | | 0.0
1269 0.3 0.3 0.003 O | | | | 0.0
1270 0.3 0.3 0.003 O | | | | 0.0
1271 0.3 0.3 0.003 O | | | | 0.0
Item #8. Page 1364
Meeting Date: 1/24/2023 / Packet Page #: 1429
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-97
1272 0.3 0.3 0.003 O | | | | 0.0
1273 0.3 0.3 0.003 O | | | | 0.0
1274 0.3 0.3 0.003 O | | | | 0.0
1275 0.3 0.3 0.003 O | | | | 0.0
1276 0.3 0.3 0.003 O | | | | 0.0
1277 0.3 0.3 0.003 O | | | | 0.0
1278 0.3 0.3 0.003 O | | | | 0.0
1279 0.3 0.3 0.003 O | | | | 0.0
1280 0.3 0.3 0.003 O | | | | 0.0
1281 0.3 0.3 0.003 O | | | | 0.0
1282 0.3 0.3 0.003 O | | | | 0.0
1283 0.3 0.3 0.003 O | | | | 0.0
1284 0.3 0.3 0.003 O | | | | 0.0
1285 0.3 0.3 0.003 O | | | | 0.0
1286 0.3 0.3 0.003 O | | | | 0.0
1287 0.3 0.3 0.003 O | | | | 0.0
1288 0.3 0.3 0.003 O | | | | 0.0
1289 0.3 0.3 0.003 O | | | | 0.0
1290 0.3 0.3 0.003 O | | | | 0.0
1291 0.3 0.3 0.003 O | | | | 0.0
1292 0.3 0.3 0.003 O | | | | 0.0
1293 0.3 0.3 0.003 O | | | | 0.0
1294 0.3 0.3 0.003 O | | | | 0.0
1295 0.2 0.3 0.003 O | | | | 0.0
1296 0.2 0.3 0.002 O | | | | 0.0
1297 0.3 0.3 0.002 O | | | | 0.0
1298 0.2 0.3 0.002 O | | | | 0.0
1299 0.2 0.3 0.002 O | | | | 0.0
1300 0.3 0.3 0.002 O | | | | 0.0
1310 0.2 0.2 0.002 O | | | | 0.0
1320 0.2 0.2 0.002 O | | | | 0.0
1330 0.2 0.2 0.002 O | | | | 0.0
1340 0.2 0.2 0.002 O | | | | 0.0
1350 0.2 0.2 0.002 O | | | | 0.0
1360 0.2 0.2 0.002 O | | | | 0.0
1370 0.2 0.2 0.002 O | | | | 0.0
1380 0.2 0.2 0.002 O | | | | 0.0
1390 0.2 0.2 0.002 O | | | | 0.0
1400 0.2 0.2 0.002 O | | | | 0.0
1420 0.2 0.2 0.002 O | | | | 0.0
1440 0.2 0.2 0.002 O | | | | 0.0
1460 0.0 0.1 0.001 O | | | | 0.0
1500 0.0 0.0 0.000 O | | | | 0.0
Remaining water in basin = 0.00 (Ac.Ft)
Peak flow out of basin = 31.38(CFS)
Peak flow time = 1154 Min., time interval # = 40
Maximum depth in basin = 1.83(Ft.)
Item #8. Page 1365
Meeting Date: 1/24/2023 / Packet Page #: 1430
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-98
Detention Subareas C, F, & H Burned Capital Flood
CIVILCADD/CIVILDESIGN Engineering Software, (c) 1997-2009 Version 6.5 -------------------------------------------------------------------- Study Date : 08/02/18 Input hydrograph file name : prpcbu.hyd Output hydrograph file name: c50bu.hin
Program computation of outflow v. depth
************************************************************ CALCULATED OUTFLOW DATA AT DEPTH = 1.00(Ft.)
************************************************************ Weir capacity using equation Q = CLH^Exp(Using Feet as units) Weir Length = 3.00(Ft.) C value = 3.00 Exp = 1.50
Weir flow: Depth = H = 1.00(Ft.) Flow = 9.00 (CFS)
Total outflow at this depth = 9.00(CFS)
************************************************************ CALCULATED OUTFLOW DATA AT DEPTH = 2.00(Ft.)
************************************************************ Weir capacity using equation Q = CLH^Exp(Using Feet as units) Weir Length = 3.00(Ft.) C value = 3.00 Exp = 1.50
Weir flow: Depth = H = 2.00(Ft.) Flow = 25.46 (CFS)
Weir capacity using equation Q = CLH^Exp(Using Feet as units) Weir Length = 10.00(Ft.) C value = 3.00 Exp = 1.50
Weir flow: Depth = H = 0.50(Ft.) Flow = 10.61 (CFS)
Total outflow at this depth = 36.06(CFS)
-------------------------------------------------------------------- Hydrograph time unit varies
Initial depth in storage basin = 0.00(Ft.)
-------------------------------------------------------------------- -------------------------------------------------------------------- Initial basin depth = 0.00 (Ft.)
Initial basin storage = 0.00 (Ac.Ft)
Initial basin outflow = 0.00 (CFS)
--------------------------------------------------------------------- -------------------------------------------------------------------- Depth vs. Storage and Depth vs. Discharge data @ 1 Min. Intervals:

Basin Depth Storage Outflow (S-O*dt/2) (S+O*dt/2)
(Ft.) (Ac.Ft) (CFS) (Ac.Ft) (Ac.Ft)
---------------------------------------------------------------------

0.000 0.000 0.000 0.000 0.000

1.000 0.080 9.000 0.074 0.086

2.000 0.190 36.062 0.165 0.215
-------------------------------------------------------------------- Hydrograph Detention Basin Routing
Hydrograph at 5 3 A Storm Day: 4 Drainage Area = 9.00
Total flood hydrograph volume this storm day = 2.51 Ac. Ft. --------------------------------------------------------------------- Graph values: 'I'= unit inflow; 'O'=outflow at time shown --------------------------------------------------------------------- Time Inflow Outflow Storage Depth
(Min) (CFS) (CFS) (Ac.Ft) .0 10.4 20.9 31.3 41.8 (Ft.)
0 0.0 0.0 0.000 O | | | | 0.0
100 0.4 0.4 0.003 O | | | | 0.0
200 0.5 0.5 0.004 O | | | | 0.1
300 0.5 0.5 0.004 O | | | | 0.1
400 0.5 0.5 0.004 O | | | | 0.1
500 0.5 0.5 0.004 O | | | | 0.1
600 0.6 0.6 0.005 O | | | | 0.1
700 0.6 0.6 0.005 O | | | | 0.1
800 0.8 0.8 0.007 O | | | | 0.1
900 1.1 1.1 0.010 O | | | | 0.1
Item #8. Page 1366
Meeting Date: 1/24/2023 / Packet Page #: 1431
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-99
1000 1.6 1.6 0.014 |O | | | | 0.2
1050 2.4 2.3 0.020 |O | | | | 0.3
1100 3.5 3.4 0.030 | O | | | | 0.4
1110 4.9 4.2 0.037 | O | | | | 0.5
1120 5.6 5.1 0.046 | OI | | | | 0.6
1130 6.9 6.2 0.055 | OI | | | | 0.7
1131 7.1 6.3 0.056 | OI | | | | 0.7
1132 7.3 6.5 0.057 | OI | | | | 0.7
1133 7.7 6.6 0.059 | O | | | | 0.7
1134 8.1 6.8 0.061 | OI | | | | 0.8
1135 8.4 7.1 0.063 | OI | | | | 0.8
1136 8.5 7.3 0.065 | OI | | | | 0.8
1137 9.0 7.5 0.067 | OI | | | | 0.8
1138 9.3 7.8 0.069 | O I| | | | 0.9
1139 9.6 8.0 0.071 | OI| | | | 0.9
1140 9.9 8.3 0.074 | OI| | | | 0.9
1141 10.7 8.7 0.077 | O I | | | 1.0
1142 11.1 9.0 0.080 | O I | | | 1.0
1143 11.5 9.7 0.083 | OI | | | 1.0
1144 12.0 10.4 0.086 | O|I | | | 1.1
1145 13.3 11.2 0.089 | O I | | | 1.1
1146 14.1 12.1 0.092 | |OI | | | 1.1
1147 15.0 12.9 0.096 | |O I | | | 1.1
1148 15.8 13.8 0.099 | | O I | | | 1.2
1149 21.6 16.0 0.109 | | O I | | 1.3
1150 26.6 19.1 0.121 | | O | I | | 1.4
1151 31.6 22.7 0.136 | | |O I | 1.5
1152 36.7 26.8 0.152 | | | O | I | 1.7
1153 41.8 31.1 0.170 | | | O| I| 1.8
1154 36.8 32.8 0.177 | | | |O I | 1.9
1155 30.8 32.2 0.174 | | | IO | 1.9
1156 24.5 30.0 0.165 | | | I O | | 1.8
1157 17.8 26.4 0.151 | | I | O | | 1.6
1158 11.1 22.0 0.133 | I O | | 1.5
1159 9.1 18.3 0.118 | I | O | | | 1.3
1160 7.9 15.3 0.105 | I | O | | | 1.2
1161 7.2 12.9 0.096 | I |O | | | 1.1
1162 6.5 11.1 0.088 | I O | | | 1.1
1163 6.0 9.6 0.082 | I O| | | | 1.0
1164 5.6 8.7 0.078 | I O | | | | 1.0
1165 5.2 8.2 0.073 | I O | | | | 0.9
1166 4.9 7.7 0.069 | I O | | | | 0.9
1167 4.7 7.3 0.065 | I O | | | | 0.8
1168 4.4 6.9 0.061 | I O | | | | 0.8
1169 4.2 6.5 0.058 | IO | | | | 0.7
1170 4.0 6.1 0.055 | IO | | | | 0.7
1171 3.9 5.8 0.052 | I O | | | | 0.6
1172 3.7 5.5 0.049 | I O | | | | 0.6
1173 3.5 5.2 0.046 | IO | | | | 0.6
1174 3.4 5.0 0.044 | IO | | | | 0.6
1175 3.3 4.7 0.042 | IO | | | | 0.5
1176 3.2 4.5 0.040 | IO | | | | 0.5
1177 3.1 4.3 0.038 | IO | | | | 0.5
1178 3.1 4.1 0.037 | IO | | | | 0.5
1179 2.9 4.0 0.035 | IO | | | | 0.4
1180 2.8 3.8 0.034 | O | | | | 0.4
1181 2.8 3.6 0.032 | O | | | | 0.4
1182 2.7 3.5 0.031 | O | | | | 0.4
1183 2.6 3.4 0.030 |IO | | | | 0.4
1184 2.5 3.3 0.029 |IO | | | | 0.4
1185 2.5 3.1 0.028 |IO | | | | 0.3
1186 2.3 3.0 0.027 |IO | | | | 0.3
1187 2.3 2.9 0.026 |IO | | | | 0.3
1188 2.2 2.8 0.025 |IO | | | | 0.3
1189 2.2 2.7 0.024 |IO | | | | 0.3
1190 2.1 2.6 0.023 |IO | | | | 0.3
1191 2.1 2.6 0.023 |O | | | | 0.3
1192 2.0 2.5 0.022 |O | | | | 0.3
1193 2.0 2.4 0.021 |O | | | | 0.3
1194 2.0 2.4 0.021 |O | | | | 0.3
1195 1.9 2.3 0.020 |O | | | | 0.3
1196 1.9 2.2 0.020 |O | | | | 0.2
1197 1.9 2.2 0.019 |O | | | | 0.2
1198 1.8 2.1 0.019 |O | | | | 0.2
1199 1.8 2.1 0.018 |O | | | | 0.2
1200 1.8 2.0 0.018 |O | | | | 0.2
Item #8. Page 1367
Meeting Date: 1/24/2023 / Packet Page #: 1432
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-100
1201 1.7 2.0 0.018 |O | | | | 0.2
1202 1.7 1.9 0.017 |O | | | | 0.2
1203 1.7 1.9 0.017 |O | | | | 0.2
1204 1.6 1.9 0.017 |O | | | | 0.2
1205 1.6 1.8 0.016 |O | | | | 0.2
1206 1.6 1.8 0.016 |O | | | | 0.2
1207 1.6 1.8 0.016 |O | | | | 0.2
1208 1.5 1.7 0.015 |O | | | | 0.2
1209 1.5 1.7 0.015 |O | | | | 0.2
1210 1.5 1.7 0.015 |O | | | | 0.2
1211 1.4 1.6 0.014 |O | | | | 0.2
1212 1.4 1.6 0.014 |O | | | | 0.2
1213 1.4 1.6 0.014 |O | | | | 0.2
1214 1.4 1.5 0.014 |O | | | | 0.2
1215 1.4 1.5 0.014 |O | | | | 0.2
1216 1.4 1.5 0.013 |O | | | | 0.2
1217 1.3 1.5 0.013 IO | | | | 0.2
1218 1.3 1.5 0.013 IO | | | | 0.2
1219 1.4 1.4 0.013 |O | | | | 0.2
1220 1.3 1.4 0.013 IO | | | | 0.2
1221 1.3 1.4 0.012 IO | | | | 0.2
1222 1.3 1.4 0.012 IO | | | | 0.2
1223 1.3 1.4 0.012 IO | | | | 0.2
1224 1.2 1.4 0.012 IO | | | | 0.2
1225 1.2 1.3 0.012 IO | | | | 0.1
1226 1.2 1.3 0.012 IO | | | | 0.1
1227 1.1 1.3 0.011 O | | | | 0.1
1228 1.1 1.3 0.011 O | | | | 0.1
1229 1.1 1.2 0.011 O | | | | 0.1
1230 1.1 1.2 0.011 O | | | | 0.1
1231 1.0 1.2 0.011 O | | | | 0.1
1232 1.1 1.2 0.010 O | | | | 0.1
1233 1.1 1.2 0.010 O | | | | 0.1
1234 1.0 1.1 0.010 O | | | | 0.1
1235 1.0 1.1 0.010 O | | | | 0.1
1236 1.0 1.1 0.010 O | | | | 0.1
1237 1.0 1.1 0.010 O | | | | 0.1
1238 0.9 1.1 0.009 O | | | | 0.1
1239 1.0 1.1 0.009 O | | | | 0.1
1240 0.9 1.0 0.009 O | | | | 0.1
1241 1.0 1.0 0.009 O | | | | 0.1
1242 0.9 1.0 0.009 O | | | | 0.1
1243 0.9 1.0 0.009 O | | | | 0.1
1244 0.9 1.0 0.009 O | | | | 0.1
1245 0.9 1.0 0.009 O | | | | 0.1
1246 0.8 0.9 0.008 O | | | | 0.1
1247 0.8 0.9 0.008 O | | | | 0.1
1248 0.9 0.9 0.008 O | | | | 0.1
1249 0.8 0.9 0.008 O | | | | 0.1
1250 0.8 0.9 0.008 O | | | | 0.1
1251 0.8 0.9 0.008 O | | | | 0.1
1252 0.8 0.9 0.008 O | | | | 0.1
1253 0.8 0.9 0.008 O | | | | 0.1
1254 0.8 0.8 0.008 O | | | | 0.1
1255 0.8 0.8 0.007 O | | | | 0.1
1256 0.8 0.8 0.007 O | | | | 0.1
1257 0.8 0.8 0.007 O | | | | 0.1
1258 0.8 0.8 0.007 O | | | | 0.1
1259 0.8 0.8 0.007 O | | | | 0.1
1260 0.8 0.8 0.007 O | | | | 0.1
1261 0.8 0.8 0.007 O | | | | 0.1
1262 0.8 0.8 0.007 O | | | | 0.1
1263 0.8 0.8 0.007 O | | | | 0.1
1264 0.7 0.8 0.007 O | | | | 0.1
1265 0.7 0.8 0.007 O | | | | 0.1
1266 0.7 0.8 0.007 O | | | | 0.1
1267 0.7 0.8 0.007 O | | | | 0.1
1268 0.7 0.8 0.007 O | | | | 0.1
1269 0.7 0.7 0.007 O | | | | 0.1
1270 0.7 0.7 0.007 O | | | | 0.1
1271 0.7 0.7 0.007 O | | | | 0.1
1272 0.6 0.7 0.006 O | | | | 0.1
1273 0.6 0.7 0.006 O | | | | 0.1
1274 0.7 0.7 0.006 O | | | | 0.1
1275 0.6 0.7 0.006 O | | | | 0.1
1276 0.6 0.7 0.006 O | | | | 0.1
Item #8. Page 1368
Meeting Date: 1/24/2023 / Packet Page #: 1433
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-101
1277 0.6 0.7 0.006 O | | | | 0.1
1278 0.6 0.7 0.006 O | | | | 0.1
1279 0.6 0.6 0.006 O | | | | 0.1
1280 0.6 0.6 0.006 O | | | | 0.1
1281 0.6 0.6 0.006 O | | | | 0.1
1282 0.6 0.6 0.006 O | | | | 0.1
1283 0.6 0.6 0.006 O | | | | 0.1
1284 0.6 0.6 0.006 O | | | | 0.1
1285 0.6 0.6 0.005 O | | | | 0.1
1286 0.6 0.6 0.005 O | | | | 0.1
1287 0.6 0.6 0.005 O | | | | 0.1
1288 0.6 0.6 0.005 O | | | | 0.1
1289 0.6 0.6 0.005 O | | | | 0.1
1290 0.6 0.6 0.005 O | | | | 0.1
1291 0.6 0.6 0.005 O | | | | 0.1
1292 0.6 0.6 0.005 O | | | | 0.1
1293 0.6 0.6 0.005 O | | | | 0.1
1294 0.6 0.6 0.005 O | | | | 0.1
1295 0.6 0.6 0.005 O | | | | 0.1
1296 0.6 0.6 0.005 O | | | | 0.1
1297 0.6 0.6 0.005 O | | | | 0.1
1298 0.6 0.6 0.005 O | | | | 0.1
1299 0.6 0.6 0.005 O | | | | 0.1
1300 0.6 0.6 0.005 O | | | | 0.1
1310 0.6 0.6 0.005 O | | | | 0.1
1320 0.6 0.6 0.005 O | | | | 0.1
1330 0.5 0.5 0.005 O | | | | 0.1
1340 0.5 0.5 0.005 O | | | | 0.1
1350 0.5 0.5 0.004 O | | | | 0.1
1360 0.5 0.5 0.004 O | | | | 0.1
1370 0.5 0.5 0.004 O | | | | 0.1
1380 0.5 0.5 0.004 O | | | | 0.1
1390 0.5 0.5 0.004 O | | | | 0.1
1400 0.5 0.5 0.004 O | | | | 0.1
1420 0.4 0.4 0.004 O | | | | 0.0
1440 0.4 0.4 0.004 O | | | | 0.0
1460 0.0 0.1 0.001 O | | | | 0.0
1500 0.0 0.0 0.000 O | | | | 0.0
Remaining water in basin = 0.00 (Ac.Ft)
Peak flow out of basin = 32.77(CFS)
Peak flow time = 1154 Min., time interval # = 40
Maximum depth in basin = 1.88(Ft.)
Item #8. Page 1369
Meeting Date: 1/24/2023 / Packet Page #: 1434
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-102
Detention Subarea D Clear Water Urban Flood
CIVILCADD/CIVILDESIGN Engineering Software, (c) 1997-2009 Version 6.5 -------------------------------------------------------------------- Study Date : 08/02/18 Input hydrograph file name : prpd25.hyd Output hydrograph file name: d25.hin
Program computation of outflow v. depth
************************************************************ CALCULATED OUTFLOW DATA AT DEPTH = 1.00(Ft.)
************************************************************ Weir capacity using equation Q = CLH^Exp(Using Feet as units) Weir Length = 3.00(Ft.) C value = 3.00 Exp = 1.50
Weir flow: Depth = H = 1.00(Ft.) Flow = 9.00 (CFS)
Total outflow at this depth = 9.00(CFS)
************************************************************ CALCULATED OUTFLOW DATA AT DEPTH = 2.00(Ft.)
************************************************************ Weir capacity using equation Q = CLH^Exp(Using Feet as units) Weir Length = 3.00(Ft.) C value = 3.00 Exp = 1.50
Weir flow: Depth = H = 2.00(Ft.) Flow = 25.46 (CFS)
Weir capacity using equation Q = CLH^Exp(Using Feet as units) Weir Length = 10.00(Ft.) C value = 3.00 Exp = 1.50
Weir flow: Depth = H = 0.40(Ft.) Flow = 7.59 (CFS)
Total outflow at this depth = 33.05(CFS)
************************************************************ CALCULATED OUTFLOW DATA AT DEPTH = 3.00(Ft.)
************************************************************ Weir capacity using equation Q = CLH^Exp(Using Feet as units) Weir Length = 3.00(Ft.) C value = 3.00 Exp = 1.50
Weir flow: Depth = H = 3.00(Ft.) Flow = 46.77 (CFS)
Weir capacity using equation Q = CLH^Exp(Using Feet as units) Weir Length = 10.00(Ft.) C value = 3.00 Exp = 1.50
Weir flow: Depth = H = 1.40(Ft.) Flow = 49.70 (CFS)
Total outflow at this depth = 96.46(CFS)
-------------------------------------------------------------------- Hydrograph time unit varies
Initial depth in storage basin = 0.00(Ft.)
-------------------------------------------------------------------- -------------------------------------------------------------------- Initial basin depth = 0.00 (Ft.)
Initial basin storage = 0.00 (Ac.Ft)
Initial basin outflow = 0.00 (CFS)
--------------------------------------------------------------------- -------------------------------------------------------------------- Depth vs. Storage and Depth vs. Discharge data @ 1 Min. Intervals:

Basin Depth Storage Outflow (S-O*dt/2) (S+O*dt/2)
(Ft.) (Ac.Ft) (CFS) (Ac.Ft) (Ac.Ft)
---------------------------------------------------------------------

0.000 0.000 0.000 0.000 0.000

1.000 0.080 9.000 0.074 0.086

2.000 0.200 33.045 0.177 0.223

3.000 0.400 96.460 0.334 0.466
Item #8. Page 1370
Meeting Date: 1/24/2023 / Packet Page #: 1435
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-103
-------------------------------------------------------------------- Hydrograph Detention Basin Routing
Hydrograph at 5 3 A Storm Day: 4 Drainage Area = 18.00
Total flood hydrograph volume this storm day = 2.79 Ac. Ft. --------------------------------------------------------------------- Graph values: 'I'= unit inflow; 'O'=outflow at time shown --------------------------------------------------------------------- Time Inflow Outflow Storage Depth
(Min) (CFS) (CFS) (Ac.Ft) .0 15.6 31.1 46.7 62.2 (Ft.)
0 0.0 0.1 0.001 O | | | | 0.0
100 0.2 0.2 0.002 O | | | | 0.0
200 0.2 0.2 0.002 O | | | | 0.0
300 0.3 0.3 0.003 O | | | | 0.0
400 0.4 0.4 0.004 O | | | | 0.0
500 0.4 0.4 0.004 O | | | | 0.0
600 0.4 0.4 0.004 O | | | | 0.0
700 0.5 0.5 0.004 O | | | | 0.1
800 0.5 0.5 0.004 O | | | | 0.1
900 0.8 0.8 0.007 O | | | | 0.1
1000 1.6 1.6 0.014 O | | | | 0.2
1050 2.7 2.6 0.023 |O | | | | 0.3
1100 4.4 4.2 0.037 | O | | | | 0.5
1110 6.2 5.3 0.047 | OI | | | | 0.6
1120 7.7 6.8 0.061 | O | | | | 0.8
1130 9.5 8.5 0.075 | O | | | | 0.9
1131 9.8 8.7 0.077 | OI | | | | 1.0
1132 10.1 8.9 0.079 | OI | | | | 1.0
1133 10.5 9.2 0.081 | OI | | | | 1.0
1134 10.9 9.6 0.083 | OI | | | | 1.0
1135 11.5 10.1 0.085 | O | | | | 1.0
1136 11.9 10.5 0.087 | OI | | | | 1.1
1137 12.6 11.0 0.090 | OI | | | | 1.1
1138 13.1 11.5 0.093 | OI | | | | 1.1
1139 13.6 12.0 0.095 | O | | | | 1.1
1140 14.1 12.5 0.098 | OI| | | | 1.1
1141 15.0 13.1 0.101 | OI| | | | 1.2
1142 15.7 13.8 0.104 | OI | | | 1.2
1143 16.5 14.4 0.107 | OI | | | 1.2
1144 17.3 15.1 0.111 | OI | | | 1.3
1145 18.7 16.0 0.115 | OI | | | 1.3
1146 20.0 17.0 0.120 | O I | | | 1.3
1147 21.5 18.1 0.125 | |O I | | | 1.4
1148 23.0 19.3 0.131 | |O I | | | 1.4
1149 28.0 21.4 0.142 | | O I | | | 1.5
1150 34.6 24.6 0.158 | | O |I | | 1.6
1151 42.8 29.0 0.180 | | O | I | | 1.8
1152 51.9 35.3 0.207 | | | O | I | 2.0
1153 61.3 44.6 0.236 | | | O | I| 2.2
1154 62.2 50.9 0.256 | | | | O I 2.3
1155 57.5 53.3 0.264 | | | | O I | 2.3
1156 48.9 51.7 0.259 | | | |IO | 2.3
1157 38.9 47.1 0.244 | | | I O | 2.2
1158 28.6 40.5 0.223 | | I | O | | 2.1
1159 21.7 33.7 0.202 | | I |O | | 2.0
1160 16.8 29.4 0.182 | I O| | | 1.8
1161 13.8 25.6 0.163 | I| O | | | 1.7
1162 11.7 22.2 0.146 | I | O | | | 1.6
1163 10.4 19.4 0.132 | I |O | | | 1.4
1164 9.4 17.0 0.120 | I O | | | 1.3
1165 8.6 14.9 0.110 | I O| | | | 1.2
1166 7.8 13.2 0.101 | I O | | | | 1.2
1167 7.3 11.8 0.094 | I O | | | | 1.1
1168 6.8 10.6 0.088 | I O | | | | 1.1
1169 6.4 9.6 0.083 | IO | | | | 1.0
1170 6.0 8.8 0.078 | IO | | | | 1.0
1171 5.7 8.4 0.074 | I O | | | | 0.9
1172 5.4 7.9 0.071 | I O | | | | 0.9
1173 5.1 7.5 0.067 | IO | | | | 0.8
1174 4.9 7.2 0.064 | IO | | | | 0.8
1175 4.6 6.8 0.060 | IO | | | | 0.8
1176 4.4 6.4 0.057 | IO | | | | 0.7
1177 4.2 6.1 0.054 | IO | | | | 0.7
1178 4.1 5.8 0.052 | O | | | | 0.6
1179 3.8 5.5 0.049 |IO | | | | 0.6
Item #8. Page 1371
Meeting Date: 1/24/2023 / Packet Page #: 1436
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-104
1180 3.7 5.3 0.047 |IO | | | | 0.6
1181 3.6 5.0 0.045 |IO | | | | 0.6
1182 3.4 4.8 0.043 |IO | | | | 0.5
1183 3.3 4.6 0.041 |IO | | | | 0.5
1184 3.2 4.4 0.039 |IO | | | | 0.5
1185 3.1 4.2 0.037 |IO | | | | 0.5
1186 2.9 4.0 0.036 |IO | | | | 0.4
1187 2.9 3.9 0.034 |O | | | | 0.4
1188 2.7 3.7 0.033 |O | | | | 0.4
1189 2.7 3.5 0.032 |O | | | | 0.4
1190 2.6 3.4 0.030 |O | | | | 0.4
1191 2.5 3.3 0.029 |O | | | | 0.4
1192 2.4 3.2 0.028 |O | | | | 0.4
1193 2.4 3.0 0.027 |O | | | | 0.3
1194 2.3 2.9 0.026 |O | | | | 0.3
1195 2.3 2.8 0.025 |O | | | | 0.3
1196 2.2 2.8 0.024 |O | | | | 0.3
1197 2.2 2.7 0.024 |O | | | | 0.3
1198 2.1 2.6 0.023 |O | | | | 0.3
1199 2.0 2.5 0.022 |O | | | | 0.3
1200 2.0 2.4 0.022 |O | | | | 0.3
1201 1.9 2.4 0.021 IO | | | | 0.3
1202 1.9 2.3 0.020 IO | | | | 0.3
1203 1.8 2.2 0.020 IO | | | | 0.2
1204 1.7 2.1 0.019 IO | | | | 0.2
1205 1.7 2.1 0.019 IO | | | | 0.2
1206 1.7 2.0 0.018 IO | | | | 0.2
1207 1.7 2.0 0.018 IO | | | | 0.2
1208 1.6 1.9 0.017 O | | | | 0.2
1209 1.6 1.9 0.017 O | | | | 0.2
1210 1.5 1.8 0.016 O | | | | 0.2
1211 1.5 1.8 0.016 O | | | | 0.2
1212 1.5 1.7 0.015 O | | | | 0.2
1213 1.4 1.7 0.015 O | | | | 0.2
1214 1.4 1.6 0.015 O | | | | 0.2
1215 1.3 1.6 0.014 O | | | | 0.2
1216 1.3 1.6 0.014 O | | | | 0.2
1217 1.2 1.5 0.013 O | | | | 0.2
1218 1.2 1.5 0.013 O | | | | 0.2
1219 1.2 1.4 0.013 O | | | | 0.2
1220 1.2 1.4 0.012 O | | | | 0.2
1221 1.1 1.3 0.012 O | | | | 0.1
1222 1.1 1.3 0.012 O | | | | 0.1
1223 1.1 1.3 0.011 O | | | | 0.1
1224 1.1 1.3 0.011 O | | | | 0.1
1225 1.0 1.2 0.011 O | | | | 0.1
1226 1.0 1.2 0.011 O | | | | 0.1
1227 1.0 1.2 0.010 O | | | | 0.1
1228 0.9 1.1 0.010 O | | | | 0.1
1229 0.9 1.1 0.010 O | | | | 0.1
1230 0.9 1.1 0.009 O | | | | 0.1
1231 0.8 1.0 0.009 O | | | | 0.1
1232 0.9 1.0 0.009 O | | | | 0.1
1233 0.8 1.0 0.009 O | | | | 0.1
1234 0.8 1.0 0.008 O | | | | 0.1
1235 0.8 0.9 0.008 O | | | | 0.1
1236 0.8 0.9 0.008 O | | | | 0.1
1237 0.7 0.9 0.008 O | | | | 0.1
1238 0.7 0.9 0.008 O | | | | 0.1
1239 0.7 0.8 0.007 O | | | | 0.1
1240 0.7 0.8 0.007 O | | | | 0.1
1241 0.7 0.8 0.007 O | | | | 0.1
1242 0.6 0.8 0.007 O | | | | 0.1
1243 0.6 0.7 0.007 O | | | | 0.1
1244 0.6 0.7 0.006 O | | | | 0.1
1245 0.6 0.7 0.006 O | | | | 0.1
1246 0.6 0.7 0.006 O | | | | 0.1
1247 0.6 0.7 0.006 O | | | | 0.1
1248 0.6 0.7 0.006 O | | | | 0.1
1249 0.6 0.7 0.006 O | | | | 0.1
1250 0.6 0.6 0.006 O | | | | 0.1
1251 0.6 0.6 0.006 O | | | | 0.1
1252 0.5 0.6 0.006 O | | | | 0.1
1253 0.5 0.6 0.005 O | | | | 0.1
1254 0.5 0.6 0.005 O | | | | 0.1
1255 0.5 0.6 0.005 O | | | | 0.1
Item #8. Page 1372
Meeting Date: 1/24/2023 / Packet Page #: 1437
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-105
1256 0.5 0.6 0.005 O | | | | 0.1
1257 0.5 0.6 0.005 O | | | | 0.1
1258 0.5 0.5 0.005 O | | | | 0.1
1259 0.5 0.5 0.005 O | | | | 0.1
1260 0.5 0.5 0.005 O | | | | 0.1
1261 0.5 0.5 0.005 O | | | | 0.1
1262 0.5 0.5 0.005 O | | | | 0.1
1263 0.5 0.5 0.005 O | | | | 0.1
1264 0.5 0.5 0.005 O | | | | 0.1
1265 0.5 0.5 0.005 O | | | | 0.1
1266 0.5 0.5 0.005 O | | | | 0.1
1267 0.5 0.5 0.005 O | | | | 0.1
1268 0.5 0.5 0.005 O | | | | 0.1
1269 0.5 0.5 0.005 O | | | | 0.1
1270 0.5 0.5 0.005 O | | | | 0.1
1271 0.5 0.5 0.005 O | | | | 0.1
1272 0.5 0.5 0.004 O | | | | 0.1
1273 0.5 0.5 0.004 O | | | | 0.1
1274 0.5 0.5 0.004 O | | | | 0.1
1275 0.5 0.5 0.004 O | | | | 0.1
1276 0.5 0.5 0.004 O | | | | 0.1
1277 0.5 0.5 0.004 O | | | | 0.1
1278 0.5 0.5 0.004 O | | | | 0.1
1279 0.5 0.5 0.004 O | | | | 0.1
1280 0.5 0.5 0.004 O | | | | 0.1
1281 0.5 0.5 0.004 O | | | | 0.1
1282 0.5 0.5 0.004 O | | | | 0.1
1283 0.5 0.5 0.004 O | | | | 0.1
1284 0.5 0.5 0.004 O | | | | 0.1
1285 0.5 0.5 0.004 O | | | | 0.1
1286 0.5 0.5 0.004 O | | | | 0.1
1287 0.5 0.5 0.004 O | | | | 0.1
1288 0.5 0.5 0.004 O | | | | 0.1
1289 0.5 0.5 0.004 O | | | | 0.1
1290 0.5 0.5 0.004 O | | | | 0.1
1291 0.5 0.5 0.004 O | | | | 0.1
1292 0.5 0.5 0.004 O | | | | 0.1
1293 0.5 0.5 0.004 O | | | | 0.1
1294 0.5 0.5 0.004 O | | | | 0.1
1295 0.4 0.5 0.004 O | | | | 0.1
1296 0.4 0.5 0.004 O | | | | 0.1
1297 0.5 0.5 0.004 O | | | | 0.1
1298 0.4 0.5 0.004 O | | | | 0.1
1299 0.4 0.5 0.004 O | | | | 0.1
1300 0.4 0.4 0.004 O | | | | 0.0
1310 0.4 0.4 0.004 O | | | | 0.0
1320 0.4 0.4 0.004 O | | | | 0.0
1330 0.4 0.4 0.004 O | | | | 0.0
1340 0.4 0.4 0.004 O | | | | 0.0
1350 0.4 0.4 0.004 O | | | | 0.0
1360 0.4 0.4 0.004 O | | | | 0.0
1370 0.4 0.4 0.004 O | | | | 0.0
1380 0.4 0.4 0.004 O | | | | 0.0
1390 0.3 0.3 0.003 O | | | | 0.0
1400 0.3 0.3 0.003 O | | | | 0.0
1420 0.2 0.2 0.002 O | | | | 0.0
1440 0.2 0.2 0.002 O | | | | 0.0
1460 0.1 0.1 0.001 O | | | | 0.0
1500 0.1 0.1 0.001 O | | | | 0.0
Remaining water in basin = 0.00 (Ac.Ft)
Peak flow out of basin = 53.27(CFS)
Peak flow time = 1155 Min., time interval # = 41
Maximum depth in basin = 2.32(Ft.)
Item #8. Page 1373
Meeting Date: 1/24/2023 / Packet Page #: 1438
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-106
Detention Subarea D Clear Water Capital Flood
CIVILCADD/CIVILDESIGN Engineering Software, (c) 1997-2009 Version 6.5 -------------------------------------------------------------------- Study Date : 08/09/18 Input hydrograph file name : prpd50.hyd Output hydrograph file name: d50cl.hin
Program computation of outflow v. depth
************************************************************ CALCULATED OUTFLOW DATA AT DEPTH = 1.00(Ft.)
************************************************************ Weir capacity using equation Q = CLH^Exp(Using Feet as units) Weir Length = 3.00(Ft.) C value = 3.00 Exp = 1.50
Weir flow: Depth = H = 1.00(Ft.) Flow = 9.00 (CFS)
Total outflow at this depth = 9.00(CFS)
************************************************************ CALCULATED OUTFLOW DATA AT DEPTH = 2.00(Ft.)
************************************************************ Weir capacity using equation Q = CLH^Exp(Using Feet as units) Weir Length = 3.00(Ft.) C value = 3.00 Exp = 1.50
Weir flow: Depth = H = 2.00(Ft.) Flow = 25.46 (CFS)
Weir capacity using equation Q = CLH^Exp(Using Feet as units) Weir Length = 10.00(Ft.) C value = 3.00 Exp = 1.50
Weir flow: Depth = H = 0.40(Ft.) Flow = 7.59 (CFS)
Total outflow at this depth = 33.05(CFS)
************************************************************ CALCULATED OUTFLOW DATA AT DEPTH = 3.00(Ft.)
************************************************************ Weir capacity using equation Q = CLH^Exp(Using Feet as units) Weir Length = 3.00(Ft.) C value = 3.00 Exp = 1.50
Weir flow: Depth = H = 3.00(Ft.) Flow = 46.77 (CFS)
Weir capacity using equation Q = CLH^Exp(Using Feet as units) Weir Length = 10.00(Ft.) C value = 3.00 Exp = 1.50
Weir flow: Depth = H = 1.40(Ft.) Flow = 49.70 (CFS)
Total outflow at this depth = 96.46(CFS)
-------------------------------------------------------------------- Hydrograph time unit varies
Initial depth in storage basin = 0.00(Ft.)
-------------------------------------------------------------------- -------------------------------------------------------------------- Initial basin depth = 0.00 (Ft.)
Initial basin storage = 0.00 (Ac.Ft)
Initial basin outflow = 0.00 (CFS)
--------------------------------------------------------------------- -------------------------------------------------------------------- Depth vs. Storage and Depth vs. Discharge data @ 1 Min. Intervals:

Basin Depth Storage Outflow (S-O*dt/2) (S+O*dt/2)
(Ft.) (Ac.Ft) (CFS) (Ac.Ft) (Ac.Ft)
---------------------------------------------------------------------

0.000 0.000 0.000 0.000 0.000

1.000 0.080 9.000 0.074 0.086

2.000 0.200 33.045 0.177 0.223
Item #8. Page 1374
Meeting Date: 1/24/2023 / Packet Page #: 1439
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-107

3.000 0.400 96.460 0.334 0.466
-------------------------------------------------------------------- Hydrograph Detention Basin Routing
Hydrograph at 5 3 A Storm Day: 4 Drainage Area = 18.00
Total flood hydrograph volume this storm day = 3.53 Ac. Ft. --------------------------------------------------------------------- Graph values: 'I'= unit inflow; 'O'=outflow at time shown --------------------------------------------------------------------- Time Inflow Outflow Storage Depth
(Min) (CFS) (CFS) (Ac.Ft) .0 18.1 36.2 54.3 72.4 (Ft.)
0 0.0 0.1 0.001 O | | | | 0.0
100 0.3 0.3 0.003 O | | | | 0.0
200 0.4 0.4 0.004 O | | | | 0.0
300 0.4 0.4 0.004 O | | | | 0.0
400 0.4 0.4 0.004 O | | | | 0.0
500 0.5 0.5 0.004 O | | | | 0.1
600 0.5 0.5 0.004 O | | | | 0.1
700 0.5 0.5 0.004 O | | | | 0.1
800 0.8 0.8 0.007 O | | | | 0.1
900 1.3 1.3 0.011 O | | | | 0.1
1000 2.2 2.1 0.019 O | | | | 0.2
1050 3.5 3.3 0.030 |O | | | | 0.4
1100 5.6 5.4 0.048 | O | | | | 0.6
1110 7.7 6.7 0.059 | OI | | | | 0.7
1120 9.4 8.4 0.075 | OI | | | | 0.9
1130 11.6 10.8 0.089 | OI | | | | 1.1
1131 11.9 11.1 0.090 | OI | | | | 1.1
1132 12.2 11.4 0.092 | O | | | | 1.1
1133 12.7 11.7 0.093 | O | | | | 1.1
1134 13.3 12.1 0.095 | O | | | | 1.1
1135 13.9 12.5 0.098 | OI | | | | 1.1
1136 14.4 13.0 0.100 | OI | | | | 1.2
1137 15.2 13.5 0.103 | OI | | | | 1.2
1138 15.8 14.1 0.105 | O | | | | 1.2
1139 16.3 14.6 0.108 | OI| | | | 1.2
1140 16.9 15.2 0.111 | OI| | | | 1.3
1141 17.9 15.8 0.114 | OI| | | | 1.3
1142 18.8 16.5 0.118 | OI | | | 1.3
1143 19.7 17.3 0.121 | OI | | | 1.3
1144 20.7 18.1 0.126 | OI | | | 1.4
1145 22.2 19.1 0.131 | OI | | | 1.4
1146 23.8 20.3 0.136 | O I | | | 1.5
1147 25.5 21.5 0.143 | |O I | | | 1.5
1148 27.2 22.9 0.149 | | O I | | | 1.6
1149 33.2 25.4 0.162 | | O I | | | 1.7
1150 40.9 29.2 0.181 | | O | I | | 1.8
1151 50.5 35.0 0.206 | | O| I | | 2.0
1152 61.0 44.3 0.235 | | | O | I | 2.2
1153 71.7 54.1 0.266 | | | O| I| 2.3
1154 72.4 60.7 0.287 | | | | O I 2.4
1155 66.6 62.8 0.294 | | | | O I | 2.5
1156 56.6 60.6 0.287 | | | |IO | 2.4
1157 45.0 55.0 0.269 | | | I O | 2.3
1158 33.0 47.1 0.244 | | I | O | | 2.2
1159 25.1 39.2 0.219 | | I |O | | 2.1
1160 19.6 32.5 0.197 | I O | | | 2.0
1161 16.2 28.5 0.177 | I| O | | | 1.8
1162 13.9 25.0 0.160 | I | O | | | 1.7
1163 12.3 21.9 0.144 | I |O | | | 1.5
1164 11.2 19.3 0.131 | I O | | | 1.4
1165 10.2 17.1 0.120 | I O| | | | 1.3
1166 9.4 15.2 0.111 | I O | | | | 1.3
1167 8.8 13.7 0.103 | I O | | | | 1.2
1168 8.2 12.3 0.097 | I O | | | | 1.1
1169 7.8 11.2 0.091 | IO | | | | 1.1
1170 7.3 10.3 0.086 | IO | | | | 1.1
1171 7.0 9.5 0.082 | IO | | | | 1.0
1172 6.7 8.9 0.079 | IO | | | | 1.0
1173 6.3 8.5 0.076 | IO | | | | 0.9
1174 6.1 8.2 0.073 | IO | | | | 0.9
1175 5.8 7.8 0.070 | IO | | | | 0.9
1176 5.5 7.5 0.067 | IO | | | | 0.8
1177 5.3 7.2 0.064 | IO | | | | 0.8
1178 5.2 6.9 0.061 | IO | | | | 0.8
Item #8. Page 1375
Meeting Date: 1/24/2023 / Packet Page #: 1440
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-108
1179 4.9 6.6 0.059 | O | | | | 0.7
1180 4.7 6.3 0.056 | O | | | | 0.7
1181 4.6 6.1 0.054 | O | | | | 0.7
1182 4.4 5.8 0.052 |IO | | | | 0.6
1183 4.3 5.6 0.050 |IO | | | | 0.6
1184 4.1 5.4 0.048 |IO | | | | 0.6
1185 4.0 5.2 0.046 |IO | | | | 0.6
1186 3.8 5.0 0.044 |IO | | | | 0.6
1187 3.7 4.8 0.043 |IO | | | | 0.5
1188 3.6 4.6 0.041 |IO | | | | 0.5
1189 3.5 4.5 0.040 |O | | | | 0.5
1190 3.4 4.3 0.038 |O | | | | 0.5
1191 3.3 4.2 0.037 |O | | | | 0.5
1192 3.2 4.0 0.036 |O | | | | 0.4
1193 3.1 3.9 0.035 |O | | | | 0.4
1194 3.1 3.8 0.034 |O | | | | 0.4
1195 3.0 3.7 0.033 |O | | | | 0.4
1196 2.9 3.6 0.032 |O | | | | 0.4
1197 2.8 3.5 0.031 |O | | | | 0.4
1198 2.8 3.4 0.030 |O | | | | 0.4
1199 2.7 3.3 0.029 |O | | | | 0.4
1200 2.6 3.2 0.028 |O | | | | 0.4
1201 2.6 3.1 0.027 |O | | | | 0.3
1202 2.5 3.0 0.027 |O | | | | 0.3
1203 2.5 2.9 0.026 |O | | | | 0.3
1204 2.4 2.9 0.025 |O | | | | 0.3
1205 2.3 2.8 0.025 |O | | | | 0.3
1206 2.3 2.7 0.024 |O | | | | 0.3
1207 2.3 2.6 0.024 |O | | | | 0.3
1208 2.2 2.6 0.023 IO | | | | 0.3
1209 2.2 2.5 0.022 IO | | | | 0.3
1210 2.2 2.5 0.022 IO | | | | 0.3
1211 2.1 2.4 0.022 IO | | | | 0.3
1212 2.1 2.4 0.021 IO | | | | 0.3
1213 2.0 2.3 0.021 IO | | | | 0.3
1214 1.9 2.3 0.020 IO | | | | 0.3
1215 1.9 2.2 0.020 O | | | | 0.2
1216 1.9 2.2 0.019 O | | | | 0.2
1217 1.8 2.1 0.019 O | | | | 0.2
1218 1.8 2.1 0.018 O | | | | 0.2
1219 1.8 2.0 0.018 O | | | | 0.2
1220 1.7 2.0 0.018 O | | | | 0.2
1221 1.7 1.9 0.017 O | | | | 0.2
1222 1.7 1.9 0.017 O | | | | 0.2
1223 1.7 1.9 0.017 O | | | | 0.2
1224 1.6 1.8 0.016 O | | | | 0.2
1225 1.6 1.8 0.016 O | | | | 0.2
1226 1.6 1.8 0.016 O | | | | 0.2
1227 1.5 1.7 0.015 O | | | | 0.2
1228 1.5 1.7 0.015 O | | | | 0.2
1229 1.4 1.7 0.015 O | | | | 0.2
1230 1.4 1.6 0.014 O | | | | 0.2
1231 1.3 1.6 0.014 O | | | | 0.2
1232 1.4 1.5 0.014 O | | | | 0.2
1233 1.3 1.5 0.013 O | | | | 0.2
1234 1.3 1.5 0.013 O | | | | 0.2
1235 1.3 1.5 0.013 O | | | | 0.2
1236 1.3 1.4 0.013 O | | | | 0.2
1237 1.2 1.4 0.012 O | | | | 0.2
1238 1.2 1.4 0.012 O | | | | 0.2
1239 1.2 1.3 0.012 O | | | | 0.1
1240 1.1 1.3 0.012 O | | | | 0.1
1241 1.2 1.3 0.012 O | | | | 0.1
1242 1.1 1.3 0.011 O | | | | 0.1
1243 1.1 1.2 0.011 O | | | | 0.1
1244 1.1 1.2 0.011 O | | | | 0.1
1245 1.1 1.2 0.011 O | | | | 0.1
1246 1.0 1.2 0.010 O | | | | 0.1
1247 1.0 1.2 0.010 O | | | | 0.1
1248 1.0 1.1 0.010 O | | | | 0.1
1249 1.0 1.1 0.010 O | | | | 0.1
1250 1.0 1.1 0.010 O | | | | 0.1
1251 1.0 1.1 0.010 O | | | | 0.1
1252 0.9 1.1 0.009 O | | | | 0.1
1253 0.9 1.0 0.009 O | | | | 0.1
1254 0.9 1.0 0.009 O | | | | 0.1
Item #8. Page 1376
Meeting Date: 1/24/2023 / Packet Page #: 1441
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-109
1255 0.8 1.0 0.009 O | | | | 0.1
1256 0.8 1.0 0.009 O | | | | 0.1
1257 0.8 0.9 0.008 O | | | | 0.1
1258 0.8 0.9 0.008 O | | | | 0.1
1259 0.8 0.9 0.008 O | | | | 0.1
1260 0.8 0.9 0.008 O | | | | 0.1
1261 0.8 0.9 0.008 O | | | | 0.1
1262 0.8 0.9 0.008 O | | | | 0.1
1263 0.7 0.8 0.007 O | | | | 0.1
1264 0.7 0.8 0.007 O | | | | 0.1
1265 0.7 0.8 0.007 O | | | | 0.1
1266 0.7 0.8 0.007 O | | | | 0.1
1267 0.7 0.8 0.007 O | | | | 0.1
1268 0.6 0.7 0.007 O | | | | 0.1
1269 0.6 0.7 0.006 O | | | | 0.1
1270 0.6 0.7 0.006 O | | | | 0.1
1271 0.6 0.7 0.006 O | | | | 0.1
1272 0.6 0.7 0.006 O | | | | 0.1
1273 0.6 0.7 0.006 O | | | | 0.1
1274 0.6 0.7 0.006 O | | | | 0.1
1275 0.6 0.7 0.006 O | | | | 0.1
1276 0.6 0.6 0.006 O | | | | 0.1
1277 0.6 0.6 0.006 O | | | | 0.1
1278 0.6 0.6 0.006 O | | | | 0.1
1279 0.6 0.6 0.006 O | | | | 0.1
1280 0.6 0.6 0.006 O | | | | 0.1
1281 0.5 0.6 0.005 O | | | | 0.1
1282 0.5 0.6 0.005 O | | | | 0.1
1283 0.5 0.6 0.005 O | | | | 0.1
1284 0.5 0.6 0.005 O | | | | 0.1
1285 0.5 0.6 0.005 O | | | | 0.1
1286 0.5 0.5 0.005 O | | | | 0.1
1287 0.5 0.5 0.005 O | | | | 0.1
1288 0.5 0.5 0.005 O | | | | 0.1
1289 0.5 0.5 0.005 O | | | | 0.1
1290 0.5 0.5 0.005 O | | | | 0.1
1291 0.5 0.5 0.005 O | | | | 0.1
1292 0.5 0.5 0.005 O | | | | 0.1
1293 0.5 0.5 0.005 O | | | | 0.1
1294 0.5 0.5 0.005 O | | | | 0.1
1295 0.5 0.5 0.005 O | | | | 0.1
1296 0.5 0.5 0.005 O | | | | 0.1
1297 0.5 0.5 0.005 O | | | | 0.1
1298 0.5 0.5 0.005 O | | | | 0.1
1299 0.5 0.5 0.005 O | | | | 0.1
1300 0.5 0.5 0.004 O | | | | 0.1
1310 0.5 0.5 0.004 O | | | | 0.1
1320 0.5 0.5 0.004 O | | | | 0.1
1330 0.5 0.5 0.004 O | | | | 0.1
1340 0.4 0.4 0.004 O | | | | 0.0
1350 0.4 0.4 0.004 O | | | | 0.0
1360 0.4 0.4 0.004 O | | | | 0.0
1370 0.4 0.4 0.004 O | | | | 0.0
1380 0.4 0.4 0.004 O | | | | 0.0
1390 0.4 0.4 0.004 O | | | | 0.0
1400 0.4 0.4 0.004 O | | | | 0.0
1420 0.4 0.4 0.004 O | | | | 0.0
1440 0.4 0.4 0.004 O | | | | 0.0
1460 0.1 0.2 0.002 O | | | | 0.0
1500 0.1 0.1 0.001 O | | | | 0.0
Remaining water in basin = 0.00 (Ac.Ft)
Peak flow out of basin = 62.80(CFS)
Peak flow time = 1155 Min., time interval # = 41
Maximum depth in basin = 2.47(Ft.)
Item #8. Page 1377
Meeting Date: 1/24/2023 / Packet Page #: 1442
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-110
Detention Subarea D Burned Capital Flood
CIVILCADD/CIVILDESIGN Engineering Software, (c) 1997-2009 Version 6.5 -------------------------------------------------------------------- Study Date : 08/02/18 Input hydrograph file name : prpdbu.hyd Output hydrograph file name: d50.hin
Program computation of outflow v. depth
************************************************************ CALCULATED OUTFLOW DATA AT DEPTH = 1.00(Ft.)
************************************************************ Weir capacity using equation Q = CLH^Exp(Using Feet as units) Weir Length = 3.00(Ft.) C value = 3.00 Exp = 1.50
Weir flow: Depth = H = 1.00(Ft.) Flow = 9.00 (CFS)
Total outflow at this depth = 9.00(CFS)
************************************************************ CALCULATED OUTFLOW DATA AT DEPTH = 2.00(Ft.)
************************************************************ Weir capacity using equation Q = CLH^Exp(Using Feet as units) Weir Length = 3.00(Ft.) C value = 3.00 Exp = 1.50
Weir flow: Depth = H = 2.00(Ft.) Flow = 25.46 (CFS)
Weir capacity using equation Q = CLH^Exp(Using Feet as units) Weir Length = 10.00(Ft.) C value = 3.00 Exp = 1.50
Weir flow: Depth = H = 0.40(Ft.) Flow = 7.59 (CFS)
Total outflow at this depth = 33.05(CFS)
************************************************************ CALCULATED OUTFLOW DATA AT DEPTH = 3.00(Ft.)
************************************************************ Weir capacity using equation Q = CLH^Exp(Using Feet as units) Weir Length = 3.00(Ft.) C value = 3.00 Exp = 1.50
Weir flow: Depth = H = 3.00(Ft.) Flow = 46.77 (CFS)
Weir capacity using equation Q = CLH^Exp(Using Feet as units) Weir Length = 10.00(Ft.) C value = 3.00 Exp = 1.50
Weir flow: Depth = H = 1.40(Ft.) Flow = 49.70 (CFS)
Total outflow at this depth = 96.46(CFS)
-------------------------------------------------------------------- Hydrograph time unit varies
Initial depth in storage basin = 0.00(Ft.)
-------------------------------------------------------------------- -------------------------------------------------------------------- Initial basin depth = 0.00 (Ft.)
Initial basin storage = 0.00 (Ac.Ft)
Initial basin outflow = 0.00 (CFS)
--------------------------------------------------------------------- -------------------------------------------------------------------- Depth vs. Storage and Depth vs. Discharge data @ 1 Min. Intervals:

Basin Depth Storage Outflow (S-O*dt/2) (S+O*dt/2)
(Ft.) (Ac.Ft) (CFS) (Ac.Ft) (Ac.Ft)
---------------------------------------------------------------------

0.000 0.000 0.000 0.000 0.000

1.000 0.080 9.000 0.074 0.086

2.000 0.200 33.045 0.177 0.223

3.000 0.400 96.460 0.334 0.466
-------------------------------------------------------------------- Item #8. Page 1378
Meeting Date: 1/24/2023 / Packet Page #: 1443
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-111
Hydrograph Detention Basin Routing
Hydrograph at 5 3 A Storm Day: 4 Drainage Area = 18.00
Total flood hydrograph volume this storm day = 5.04 Ac. Ft. --------------------------------------------------------------------- Graph values: 'I'= unit inflow; 'O'=outflow at time shown --------------------------------------------------------------------- Time Inflow Outflow Storage Depth
(Min) (CFS) (CFS) (Ac.Ft) .0 18.8 37.6 56.5 75.3 (Ft.)
0 0.0 0.1 0.001 O | | | | 0.0
100 0.9 0.8 0.008 O | | | | 0.1
200 0.9 0.9 0.008 O | | | | 0.1
300 0.9 0.9 0.008 O | | | | 0.1
400 1.0 1.0 0.009 O | | | | 0.1
500 1.1 1.1 0.010 O | | | | 0.1
600 1.1 1.1 0.010 O | | | | 0.1
700 1.2 1.2 0.011 O | | | | 0.1
800 1.6 1.6 0.014 O | | | | 0.2
900 2.2 2.2 0.019 O | | | | 0.2
1000 3.2 3.1 0.028 |O | | | | 0.3
1050 4.7 4.5 0.040 |O | | | | 0.5
1100 6.9 6.6 0.059 | O | | | | 0.7
1110 9.2 8.1 0.072 | O | | | | 0.9
1120 11.0 10.3 0.087 | O | | | | 1.1
1130 13.3 12.6 0.098 | O | | | | 1.1
1131 13.7 12.9 0.099 | O | | | | 1.2
1132 14.0 13.1 0.101 | O | | | | 1.2
1133 14.5 13.5 0.102 | OI | | | | 1.2
1134 15.1 13.9 0.104 | OI | | | | 1.2
1135 15.8 14.3 0.107 | O | | | | 1.2
1136 16.3 14.8 0.109 | O | | | | 1.2
1137 17.1 15.4 0.112 | OI| | | | 1.3
1138 17.7 15.9 0.115 | OI| | | | 1.3
1139 18.3 16.5 0.117 | O| | | | 1.3
1140 18.9 17.1 0.120 | OI | | | 1.3
1141 20.0 17.8 0.124 | OI | | | 1.4
1142 20.9 18.5 0.128 | OI | | | 1.4
1143 21.8 19.3 0.132 | OI | | | 1.4
1144 22.8 20.2 0.136 | OI | | | 1.5
1145 24.5 21.2 0.141 | |OI | | | 1.5
1146 26.1 22.4 0.147 | |O I | | | 1.6
1147 27.9 23.7 0.154 | | OI | | | 1.6
1148 29.6 25.2 0.161 | | O I | | | 1.7
1149 35.7 27.7 0.173 | | O I| | | 1.8
1150 43.6 31.6 0.193 | | O | I | | 1.9
1151 53.4 38.7 0.218 | | O I | | 2.1
1152 63.9 47.7 0.246 | | | O | I | 2.2
1153 74.6 57.4 0.277 | | | O I| 2.4
1154 75.3 63.8 0.297 | | | | O I 2.5
1155 69.4 65.8 0.303 | | | | O I | 2.5
1156 59.2 63.4 0.296 | | | |IO | 2.5
1157 47.4 57.7 0.278 | | | I O | 2.4
1158 35.2 49.6 0.252 | | I | O | | 2.3
1159 27.0 41.5 0.227 | | I |O | | 2.1
1160 21.4 34.3 0.204 | |I O | | | 2.0
1161 18.0 29.9 0.185 | I| O | | | 1.9
1162 15.6 26.5 0.167 | I | O | | | 1.7
1163 14.0 23.4 0.152 | I |O | | | 1.6
1164 12.8 20.9 0.139 | I O | | | 1.5
1165 11.8 18.7 0.128 | I O| | | | 1.4
1166 11.0 16.8 0.119 | I O| | | | 1.3
1167 10.3 15.2 0.111 | I O | | | | 1.3
1168 9.7 13.9 0.104 | IO | | | | 1.2
1169 9.2 12.7 0.099 | I O | | | | 1.2
1170 8.7 11.8 0.094 | I O | | | | 1.1
1171 8.4 11.0 0.090 | IO | | | | 1.1
1172 8.0 10.2 0.086 | IO | | | | 1.1
1173 7.7 9.6 0.083 | IO | | | | 1.0
1174 7.4 9.1 0.080 | O | | | | 1.0
1175 7.1 8.8 0.078 | O | | | | 1.0
1176 6.8 8.5 0.075 | IO | | | | 0.9
1177 6.6 8.2 0.073 | IO | | | | 0.9
1178 6.4 8.0 0.071 | IO | | | | 0.9
1179 6.2 7.7 0.068 | IO | | | | 0.9
1180 6.0 7.5 0.066 | IO | | | | 0.8
Item #8. Page 1379
Meeting Date: 1/24/2023 / Packet Page #: 1444
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-112
1181 5.8 7.2 0.064 | IO | | | | 0.8
1182 5.6 7.0 0.062 | O | | | | 0.8
1183 5.5 6.8 0.060 | O | | | | 0.8
1184 5.3 6.6 0.058 | O | | | | 0.7
1185 5.2 6.4 0.057 | O | | | | 0.7
1186 5.0 6.2 0.055 | O | | | | 0.7
1187 4.9 6.0 0.053 | O | | | | 0.7
1188 4.7 5.8 0.052 |IO | | | | 0.6
1189 4.6 5.6 0.050 |IO | | | | 0.6
1190 4.5 5.5 0.049 |IO | | | | 0.6
1191 4.4 5.3 0.047 |IO | | | | 0.6
1192 4.3 5.2 0.046 |IO | | | | 0.6
1193 4.2 5.0 0.045 |IO | | | | 0.6
1194 4.1 4.9 0.044 |IO | | | | 0.5
1195 4.1 4.8 0.042 |IO | | | | 0.5
1196 4.0 4.7 0.041 |O | | | | 0.5
1197 3.9 4.6 0.041 |O | | | | 0.5
1198 3.8 4.4 0.040 |O | | | | 0.5
1199 3.7 4.3 0.039 |O | | | | 0.5
1200 3.7 4.2 0.038 |O | | | | 0.5
1201 3.6 4.2 0.037 |O | | | | 0.5
1202 3.5 4.1 0.036 |O | | | | 0.5
1203 3.5 4.0 0.035 |O | | | | 0.4
1204 3.4 3.9 0.035 |O | | | | 0.4
1205 3.3 3.8 0.034 |O | | | | 0.4
1206 3.3 3.7 0.033 |O | | | | 0.4
1207 3.3 3.7 0.033 |O | | | | 0.4
1208 3.2 3.6 0.032 |O | | | | 0.4
1209 3.1 3.5 0.031 |O | | | | 0.4
1210 3.1 3.5 0.031 |O | | | | 0.4
1211 3.0 3.4 0.030 |O | | | | 0.4
1212 3.0 3.3 0.030 |O | | | | 0.4
1213 3.0 3.3 0.029 |O | | | | 0.4
1214 2.9 3.2 0.029 |O | | | | 0.4
1215 2.8 3.2 0.028 |O | | | | 0.4
1216 2.8 3.1 0.028 |O | | | | 0.3
1217 2.7 3.1 0.027 |O | | | | 0.3
1218 2.7 3.0 0.027 |O | | | | 0.3
1219 2.7 3.0 0.026 |O | | | | 0.3
1220 2.6 2.9 0.026 |O | | | | 0.3
1221 2.6 2.9 0.025 |O | | | | 0.3
1222 2.6 2.8 0.025 |O | | | | 0.3
1223 2.6 2.8 0.025 |O | | | | 0.3
1224 2.5 2.8 0.024 |O | | | | 0.3
1225 2.5 2.7 0.024 |O | | | | 0.3
1226 2.4 2.7 0.024 |O | | | | 0.3
1227 2.4 2.6 0.023 |O | | | | 0.3
1228 2.3 2.6 0.023 IO | | | | 0.3
1229 2.3 2.5 0.023 IO | | | | 0.3
1230 2.3 2.5 0.022 IO | | | | 0.3
1231 2.2 2.5 0.022 IO | | | | 0.3
1232 2.2 2.4 0.022 IO | | | | 0.3
1233 2.2 2.4 0.021 IO | | | | 0.3
1234 2.1 2.4 0.021 O | | | | 0.3
1235 2.1 2.3 0.021 O | | | | 0.3
1236 2.1 2.3 0.020 O | | | | 0.3
1237 2.1 2.3 0.020 O | | | | 0.3
1238 2.0 2.2 0.020 O | | | | 0.2
1239 2.0 2.2 0.019 O | | | | 0.2
1240 2.0 2.2 0.019 O | | | | 0.2
1241 2.0 2.1 0.019 O | | | | 0.2
1242 1.9 2.1 0.019 O | | | | 0.2
1243 1.9 2.1 0.018 O | | | | 0.2
1244 1.9 2.0 0.018 O | | | | 0.2
1245 1.9 2.0 0.018 O | | | | 0.2
1246 1.8 2.0 0.018 O | | | | 0.2
1247 1.8 2.0 0.017 O | | | | 0.2
1248 1.8 1.9 0.017 O | | | | 0.2
1249 1.8 1.9 0.017 O | | | | 0.2
1250 1.8 1.9 0.017 O | | | | 0.2
1251 1.7 1.9 0.017 O | | | | 0.2
1252 1.7 1.9 0.016 O | | | | 0.2
1253 1.6 1.8 0.016 O | | | | 0.2
1254 1.6 1.8 0.016 O | | | | 0.2
1255 1.6 1.8 0.016 O | | | | 0.2
1256 1.6 1.7 0.015 O | | | | 0.2
Item #8. Page 1380
Meeting Date: 1/24/2023 / Packet Page #: 1445
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-113
1257 1.6 1.7 0.015 O | | | | 0.2
1258 1.5 1.7 0.015 O | | | | 0.2
1259 1.5 1.7 0.015 O | | | | 0.2
1260 1.5 1.6 0.015 O | | | | 0.2
1261 1.5 1.6 0.014 O | | | | 0.2
1262 1.5 1.6 0.014 O | | | | 0.2
1263 1.5 1.6 0.014 O | | | | 0.2
1264 1.5 1.6 0.014 O | | | | 0.2
1265 1.4 1.5 0.014 O | | | | 0.2
1266 1.4 1.5 0.014 O | | | | 0.2
1267 1.4 1.5 0.013 O | | | | 0.2
1268 1.4 1.5 0.013 O | | | | 0.2
1269 1.4 1.5 0.013 O | | | | 0.2
1270 1.4 1.5 0.013 O | | | | 0.2
1271 1.4 1.5 0.013 O | | | | 0.2
1272 1.3 1.4 0.013 O | | | | 0.2
1273 1.3 1.4 0.013 O | | | | 0.2
1274 1.3 1.4 0.012 O | | | | 0.2
1275 1.3 1.4 0.012 O | | | | 0.2
1276 1.3 1.4 0.012 O | | | | 0.2
1277 1.3 1.4 0.012 O | | | | 0.2
1278 1.3 1.4 0.012 O | | | | 0.2
1279 1.3 1.3 0.012 O | | | | 0.1
1280 1.3 1.3 0.012 O | | | | 0.1
1281 1.3 1.3 0.012 O | | | | 0.1
1282 1.3 1.3 0.012 O | | | | 0.1
1283 1.3 1.3 0.012 O | | | | 0.1
1284 1.2 1.3 0.012 O | | | | 0.1
1285 1.3 1.3 0.012 O | | | | 0.1
1286 1.2 1.3 0.011 O | | | | 0.1
1287 1.2 1.3 0.011 O | | | | 0.1
1288 1.2 1.3 0.011 O | | | | 0.1
1289 1.2 1.3 0.011 O | | | | 0.1
1290 1.2 1.2 0.011 O | | | | 0.1
1291 1.2 1.2 0.011 O | | | | 0.1
1292 1.2 1.2 0.011 O | | | | 0.1
1293 1.2 1.2 0.011 O | | | | 0.1
1294 1.2 1.2 0.011 O | | | | 0.1
1295 1.2 1.2 0.011 O | | | | 0.1
1296 1.2 1.2 0.011 O | | | | 0.1
1297 1.2 1.2 0.011 O | | | | 0.1
1298 1.2 1.2 0.011 O | | | | 0.1
1299 1.2 1.2 0.011 O | | | | 0.1
1300 1.2 1.2 0.011 O | | | | 0.1
1310 1.1 1.1 0.010 O | | | | 0.1
1320 1.1 1.1 0.010 O | | | | 0.1
1330 1.1 1.1 0.010 O | | | | 0.1
1340 1.0 1.0 0.009 O | | | | 0.1
1350 1.0 1.0 0.009 O | | | | 0.1
1360 1.0 1.0 0.009 O | | | | 0.1
1370 1.0 1.0 0.009 O | | | | 0.1
1380 1.0 1.0 0.009 O | | | | 0.1
1390 1.0 1.0 0.009 O | | | | 0.1
1400 0.9 0.9 0.008 O | | | | 0.1
1420 0.9 0.9 0.008 O | | | | 0.1
1440 0.9 0.9 0.008 O | | | | 0.1
1460 0.6 0.7 0.006 O | | | | 0.1
1500 0.6 0.5 0.005 O | | | | 0.1
Remaining water in basin = 0.00 (Ac.Ft)
Peak flow out of basin = 65.80(CFS)
Peak flow time = 1155 Min., time interval # = 41
Maximum depth in basin = 2.52(Ft.)
Item #8. Page 1381
Meeting Date: 1/24/2023 / Packet Page #: 1446
HYDROLOGY STUDY TENTATIVE TRACT 72413
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Proposed Condition Outflow Routing in LAR04
A schematic of the proposed condition outflow routing in shown below, and the LAR04 output is shown on the immediately following pages.

Figure C – 5. Proposed conditions outflow routing schematic for LAR04.

K L M
N
Outflow
hydrograph
from elevated inlet B
Parkway drain
Flow
Split
Connect to existing storm drain
Overland flow
(Grand Ave. valley gutter)
LEGEND
X1 Subarea
Routing (overland)
Routing (storm drain)
Concentration point
Flow split (diversion)
Parkway drain
Existing storm drain
Q
R
Overland flow
to Palm Drive
Project Property Line
Outflow hydrograph
from elevated inlet C +
hydrographs
from F and H
Outflow
hydrograph
from debris basin D
Outflow
hydrograph
from elevated inlet B
12F
Project Property Line
Outflow
hydrograph
from C +
hydrographs
from F and H
Outflow
hydrograph
from debris basin D
13F
8AC
11AE
1A
3AB
2B
7CD
4C
6D
5D
10E
9E
14AF

SCHEMATIC IN REPORT
AS ENTERED IN LAR04
CP1
CP3
CP2
CP4
CP7
CP6
CP5
CP8
Flow Split
Item #8. Page 1382
Meeting Date: 1/24/2023 / Packet Page #: 1447
HYDROLOGY STUDY TENTATIVE TRACT 72413
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Table C – 5. Proposed condition cumulative areas at LAR04 concentration points LAR04 Concentration Point Cumulative drainage subareas as shown in report 1A B1, B2, B3
2B K
3AB K, B1, B2, B3
4C C, F, H
5D M
6D L, M
7CD C, F, H, L, M
8AC K, B1, B2, B3, C, F, H, L, M
9E D1, D2, D3
10E N, D1, D2, D3
11AE K, B1, B2, B3, C, F, H, L, M, N, D1, D2, D3
12F Q
13F R, Q
14AF K, B1, B2, B3, C, F, H, L, M, N, D1, D2, D3, R, Q
Item #8. Page 1383
Meeting Date: 1/24/2023 / Packet Page #: 1448
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-116
Proposed Condition Outflow Clear Water 25-Year Storm (Urban Flood) Program Package Serial Number: 2223
08/02/18 FILE: pr25 INPUT DATA: English Units RAINFALL SOIL FILE: English (In) OUTPUT DATA: English Units PAGE 1 LOS ANGELES COUNTY FLOOD CONTROL DISTRICT PROG F0601M
Version 11.3, MODIFIED RATIONAL METHOD HYDROLOGY - STORM YEAR = 25 SOIL DATA FILE: C:\LAR04\sgr_soilx_71.dat Glendora STORM DAY 4

SUBAREA SUBAREA TOTAL TOTAL CONV CONV CONV CONV CONV CONTROL SOIL RAIN PCT LOCATION AREA(Ac) Q(CFS) AREA(Ac) Q(CFS) TYPE LNGTH(Ft) SLOPE SIZE(Ft) Z Q(CFS) NAME TC ZONE IMPV 5 1A 14.0 34.10 14.0 34.10 4 318. .13000 3.00 .00 0. 81 0 A42 .00 5 2B .7 2.71 .7 2.71 4 103. .23000 3.00 .00 0. 81 5 A42 .02 5 3AB .7 2.66 14.7 35.38 4 225. .18000 3.00 .00 0. 81 0 A42 .00 5 4C 9.0 26.90 9.0 26.90 4 145. .28000 3.00 .00 0. 81 0 A42 .00 5 5D .7 2.71 .7 2.71 4 185. .01000 1.50 .00 0. 81 5 A42 .02 5 6D .7 2.71 1.4 5.10 4 41. .01000 1.50 .00 0. 81 5 A42 .02 5 7CD 1.4 5.00 10.4 31.81 4 187. .11000 3.00 .00 0. 81 0 A42 .00 5 8AC 10.4 31.59 25.1 64.73 4 277. .11000 3.00 .00 0. 81 0 A42 .00 5 9E 18.0 53.30 18.0 53.30 4 191. .26000 3.00 .00 0. 81 0 A42 .00 5 10E .5 1.94 18.5 54.41 4 532. .14000 3.00 .00 0. 81 5 A42 .02 5 11AE 18.5 53.77 43.6 118.09 3 625. .10000 3.00 .00 0. 81 0 A42 .00 5 12F 5.5 19.20 5.5 19.20 3 679. .09000 .00 .00 0. 81 6 A42 .21 5 13F 4.0 12.43 9.5 29.41 0 0. .00000 .00 .00 0. 7 6 A42 .21 5 14AF 9.5 29.41 53.1 142.02 0 0. .00000 .00 .00 0. 81 0 A42 .00 Item #8. Page 1384
Meeting Date: 1/24/2023 / Packet Page #: 1449
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-117
Proposed Condition Outflow Clear Water 50-Year Storm (Capital Flood) Program Package Serial Number: 2223
08/09/18 FILE: pr50.i INPUT DATA: English Units RAINFALL SOIL FILE: English (In) OUTPUT DATA: English Units PAGE 1 LOS ANGELES COUNTY FLOOD CONTROL DISTRICT PROG F0601M
Version 11.3, MODIFIED RATIONAL METHOD HYDROLOGY - STORM YEAR = 50 SOIL DATA FILE: C:\LAR04\sgr_soilx_71.dat Glendora STORM DAY 4

SUBAREA SUBAREA TOTAL TOTAL CONV CONV CONV CONV CONV CONTROL SOIL RAIN PCT LOCATION AREA(Ac) Q(CFS) AREA(Ac) Q(CFS) TYPE LNGTH(Ft) SLOPE SIZE(Ft) Z Q(CFS) NAME TC ZONE IMPV 5 1A 14.0 39.60 14.0 39.60 4 318. .13000 3.00 .00 0. 81 0 A42 .00 5 2B .7 3.14 .7 3.14 4 103. .23000 3.00 .00 0. 81 5 A42 .02 5 3AB .7 3.07 14.7 41.10 4 225. .18000 3.00 .00 0. 81 0 A42 .00 5 4C 9.0 31.40 9.0 31.40 4 145. .28000 3.00 .00 0. 81 0 A42 .00 5 5D .7 3.14 .7 3.14 4 185. .01000 1.50 .00 0. 81 5 A42 .02 5 6D .7 3.14 1.4 5.93 4 41. .01000 1.50 .00 0. 81 5 A42 .02 5 7CD 1.4 5.80 10.4 37.11 4 187. .11000 3.00 .00 0. 81 0 A42 .00 5 8AC 10.4 36.81 25.1 75.40 4 277. .11000 3.00 .00 0. 81 0 A42 .00 5 9E 18.0 62.80 18.0 62.80 4 191. .26000 3.00 .00 0. 81 0 A42 .00 5 10E .5 2.24 18.5 64.30 4 532. .14000 3.00 .00 0. 81 5 A42 .02 5 11AE 18.5 63.32 43.6 138.27 3 625. .10000 3.00 .00 0. 81 0 A42 .00 5 12F 5.5 22.19 5.5 22.19 3 679. .09000 .00 .00 0. 81 6 A42 .21 5 13F 4.0 14.65 9.5 34.48 0 0. .00000 .00 .00 0. 7 6 A42 .21 5 14AF 9.5 34.48 53.1 166.95 0 0. .00000 .00 .00 0. 81 0 A42 .00 Item #8. Page 1385
Meeting Date: 1/24/2023 / Packet Page #: 1450
HYDROLOGY STUDY TENTATIVE TRACT 72413
C-118
Proposed Condition Outflow Burned 50-Year Storm (Capital Flood) Program Package Serial Number: 2223
08/02/18 FILE: bu50 INPUT DATA: English Units RAINFALL SOIL FILE: English (In) OUTPUT DATA: English Units PAGE 1 LOS ANGELES COUNTY FLOOD CONTROL DISTRICT PROG F0601M
Version 11.3, MODIFIED RATIONAL METHOD HYDROLOGY - STORM YEAR = 50 SOIL DATA FILE: C:\LAR04\sgr_soilx_71.dat Glendora STORM DAY 4

SUBAREA SUBAREA TOTAL TOTAL CONV CONV CONV CONV CONV CONTROL SOIL RAIN PCT LOCATION AREA(Ac) Q(CFS) AREA(Ac) Q(CFS) TYPE LNGTH(Ft) SLOPE SIZE(Ft) Z Q(CFS) NAME TC ZONE IMPV 5 1A 14.0 42.00 14.0 42.00 4 318. .13000 3.00 .00 0. 281 0 A42 .00 5 2B .7 3.25 .7 3.25 4 103. .23000 3.00 .00 0. 281 5 A42 .02 5 3AB .7 3.18 14.7 43.49 4 225. .18000 3.00 .00 0. 281 0 A42 .00 5 4C 9.0 32.80 9.0 32.80 4 145. .28000 3.00 .00 0. 281 0 A42 .00 5 5D .7 3.25 .7 3.25 4 185. .01000 1.50 .00 0. 281 5 A42 .02 5 6D .7 3.25 1.4 6.15 4 41. .01000 1.50 .00 0. 281 5 A42 .02 5 7CD 1.4 6.02 10.4 38.72 4 187. .11000 3.00 .00 0. 281 0 A42 .00 5 8AC 10.4 38.44 25.1 79.01 4 277. .11000 3.00 .00 0. 281 0 A42 .00 5 9E 18.0 65.40 18.0 65.40 4 191. .26000 3.00 .00 0. 281 0 A42 .00 5 10E .5 2.32 18.5 66.89 4 532. .14000 3.00 .00 0. 281 5 A42 .02 5 11AE 18.5 65.99 43.6 144.52 3 625. .10000 3.00 .00 0. 281 0 A42 .00 5 12F 5.5 22.88 5.5 22.88 3 679. .09000 .00 .00 0. 281 6 A42 .21 5 13F 4.0 15.59 9.5 36.14 0 0. .00000 .00 .00 0. 207 6 A42 .21 5 14AF 9.5 36.14 53.1 174.89 0 0. .00000 .00 .00 0. 281 0 A42 .00 Item #8. Page 1386
Meeting Date: 1/24/2023 / Packet Page #: 1451
HYDROLOGY STUDY TENTATIVE TRACT 72413
D-1
Appendix D. Hydraulic Calculations
Item #8. Page 1387
Meeting Date: 1/24/2023 / Packet Page #: 1452
HYDROLOGY STUDY TENTATIVE TRACT 72413
D-2
Onsite flows will be conveyed through the proposed subdivision and into Palm Drive near the location of historic outflows from the site. In order to prevent flooding in the lots, the proposed private drives have sufficient hydraulic carrying capacity to convey the 50-year clear water flow without overtopping the curb.

Although the project has not yet moved into the detailed design phase, a typical street cross-section has been developed (Figure D – 1). As shown in Table 25, the maximum flow within the proposed subdivision under the 50 year condition is 34.5 cfs. And although the design street cross-section is not expected to change, carrying capacity in the street will be most limited just north of the entrance to the proposed subdivision at Palm Drive, since the longitudinal slope of 7% in that area a minimum within the subdivision extents.

Figure D – 1. Typical private drive road cross-section
Analysis of the street hydraulic capacity can therefore proceed by means of uniform flow analysis (e.g.

Manning’s) assuming the typical cross-section given above and the mildest slope on the site of about 6%.

Assuming a Manning’s roughness coefficient of 0.018 (corresponding to aged asphalt or rough concrete), the depth of flow at 34.5 cfs is 0.34 feet (see calculations next page). Since this is below 6” (the height of the curb), the calculation indicates that the proposed streets have sufficient hydraulic capacity to convey the 50-year design storm.

The City of Glendora has approved this approach to conveying onsite drainage (Appendix B).

Item #8. Page 1388
Meeting Date: 1/24/2023 / Packet Page #: 1453
HYDROLOGY STUDY TENTATIVE TRACT 72413
D-3
Item #8. Page 1389
Meeting Date: 1/24/2023 / Packet Page #: 1454
HYDROLOGY STUDY TENTATIVE TRACT 72413
E-1
Appendix E. LACDPW Allowance for Construction of West Basin as an Elevated Inlet Item #8. Page 1390
Meeting Date: 1/24/2023 / Packet Page #: 1455
HYDROLOGY STUDY TENTATIVE TRACT 72413
E-2
Item #8. Page 1391
Meeting Date: 1/24/2023 / Packet Page #: 1456
HYDROLOGY STUDY TENTATIVE TRACT 72413
F-1
Appendix F. Maps
Item #8. Page 1392
Meeting Date: 1/24/2023 / Packet Page #: 1457
Item #8. Page 1393
Meeting Date: 1/24/2023 / Packet Page #: 1458
51197 4/4/2019
Item #8. Page 1394
Meeting Date: 1/24/2023 / Packet Page #: 1459
Item #8. Page 1395
Meeting Date: 1/24/2023 / Packet Page #: 1460
51197 4/4/2019
Item #8. Page 1396
Meeting Date: 1/24/2023 / Packet Page #: 1461
Item #8. Page 1397
Meeting Date: 1/24/2023 / Packet Page #: 1462
Appendix F
Noise Modeling Data
Item #8. Page 1398
Meeting Date: 1/24/2023 / Packet Page #: 1463
Item #8. Page 1399
Meeting Date: 1/24/2023 / Packet Page #: 1464
APPENDIX F-1
Noise Field Data
Item #8. Page 1400
Meeting Date: 1/24/2023 / Packet Page #: 1465
Item #8. Page 1401
Meeting Date: 1/24/2023 / Packet Page #: 1466
Item #8. Page 1402
Meeting Date: 1/24/2023 / Packet Page #: 1467
Item #8. Page 1403
Meeting Date: 1/24/2023 / Packet Page #: 1468
Item #8. Page 1404
Meeting Date: 1/24/2023 / Packet Page #: 1469
Item #8. Page 1405
Meeting Date: 1/24/2023 / Packet Page #: 1470
Item #8. Page 1406
Meeting Date: 1/24/2023 / Packet Page #: 1471
Item #8. Page 1407
Meeting Date: 1/24/2023 / Packet Page #: 1472
Item #8. Page 1408
Meeting Date: 1/24/2023 / Packet Page #: 1473
Item #8. Page 1409
Meeting Date: 1/24/2023 / Packet Page #: 1474
Item #8. Page 1410
Meeting Date: 1/24/2023 / Packet Page #: 1475
Item #8. Page 1411
Meeting Date: 1/24/2023 / Packet Page #: 1476
APPENDIX F-2
Construction Noise Modelling Data
Item #8. Page 1412
Meeting Date: 1/24/2023 / Packet Page #: 1477
Glendora Hills Construction Equipment List
PhaseName OffRoadEquipmentType OffRoadEquipmentUnitAmount Site Preparation Rubber Tired Dozers 3
Site Preparation Tractors/Loaders/Backhoes 4
Grading Excavators 2
Grading Graders 1
Grading Rubber Tired Dozers 1
Grading Scrapers 2
Grading Tractors/Loaders/Backhoes 2
Building Construction Cranes 1
Building Construction Forklifts 3
Building Construction Generator Sets 1
Building Construction Tractors/Loaders/Backhoes 3
Building Construction Welders 1
Paving Pavers 2
Paving Paving Equipment 2
Paving Rollers 2
Architectural Coating Air Compressors 1
Item #8. Page 1413
Meeting Date: 1/24/2023 / Packet Page #: 1478
Roadway Construction Noise Model (RCNM),Version 1.1
Report date: 8/20/2018
Case Description: Silent Ranch - Site Preparation
---- Receptor #1 ----
Baselines (dBA)
Description Land Use Daytime Evening Night
Closest Residence Residential 55 50 45
Equipment
Spec Actual Receptor Estimated
Impact Lmax Lmax Distance Shielding
Description Device Usage(%) (dBA) (dBA) (feet) (dBA)
Dozer No 40 81.7 20 0
Dozer No 40 81.7 20 0
Dozer No 40 81.7 20 0
Front End Loader No 40 79.1 20 0
Front End Loader No 40 79.1 20 0
Front End Loader No 40 79.1 20 0
Front End Loader No 40 79.1 20 0
Dump Truck No 40 76.5 20 0
Results
Calculated (dBA)
Equipment *Lmax Leq
Dozer 89.6 85.6
Dozer 89.6 85.6
Dozer 89.6 85.6
Front End Loader 87.1 83.1
Front End Loader 87.1 83.1
Front End Loader 87.1 83.1
Front End Loader 87.1 83.1
Dump Truck 84.4 80.4
Total 89.6 93.1
*Calculated Lmax is the Loudest value.

Item #8. Page 1414
Meeting Date: 1/24/2023 / Packet Page #: 1479
---- Receptor #2 ----
Baselines (dBA)
Description Land Use Daytime Evening Night
Accoustc Center - Closest Res. Residential 55 50 45
Equipment
Spec Actual Receptor Estimated
Impact Lmax Lmax Distance Shielding
Description Device Usage(%) (dBA) (dBA) (feet) (dBA)
Dozer No 40 81.7 65 0
Dozer No 40 81.7 65 0
Dozer No 40 81.7 65 0
Front End Loader No 40 79.1 65 0
Front End Loader No 40 79.1 65 0
Front End Loader No 40 79.1 65 0
Front End Loader No 40 79.1 65 0
Dump Truck No 40 76.5 65 0
Results
Calculated (dBA)
Equipment *Lmax Leq
Dozer 79.4 75.4
Dozer 79.4 75.4
Dozer 79.4 75.4
Front End Loader 76.8 72.9
Front End Loader 76.8 72.9
Front End Loader 76.8 72.9
Front End Loader 76.8 72.9
Dump Truck 74.2 70.2
Total 79.4 82.8
*Calculated Lmax is the Loudest value.

Item #8. Page 1415
Meeting Date: 1/24/2023 / Packet Page #: 1480
Roadway Construction Noise Model (RCNM),Version 1.1
Report date:

Case Description:
8/20/2018
Silent Ranch - Grading
---- Receptor #1 ----
Baselines (dBA)
Description Land Use Daytime Evening Night
Closest Residence Residential 55 50 45
Equipment
Spec Actual Receptor Estimated
Impact Lmax Lmax Distance Shielding
Description Device Usage(%) (dBA) (dBA) (feet) (dBA)
Excavator No 40 80.7 20 0
Excavator No 40 80.7 20 0
Grader No 40 85 20 0
Dozer No 40 81.7 20 0
Scraper No 40 83.6 20 0
Scraper No 40 83.6 20 0
Front End Loader No 40 79.1 20 0
Front End Loader No 40 79.1 20 0
Dump Truck No 40 76.5 20 0
Results
Calculated (dBA)
Equipment *Lmax Leq
Excavator 88.7 84.7
Excavator 88.7 84.7
Grader 93 89
Dozer 89.6 85.6
Scraper 91.5 87.6
Scraper 91.5 87.6
Front End Loader 87.1 83.1
Front End Loader 87.1 83.1
Dump Truck 84.4 80.4
Total 93 95.3
*Calculated Lmax is the Loudest value.

Item #8. Page 1416
Meeting Date: 1/24/2023 / Packet Page #: 1481
---- Receptor #2 ----
Baselines (dBA)
Description Land Use Daytime Evening Night
Accoustc Center - Closest Res. Residential 55 50 45
Equipment
Spec Actual Receptor Estimated
Impact Lmax Lmax Distance Shielding
Description Device Usage(%) (dBA) (dBA) (feet) (dBA)
Excavator No 40 80.7 65 0
Excavator No 40 80.7 65 0
Grader No 40 85 65 0
Dozer No 40 81.7 65 0
Scraper No 40 83.6 65 0
Scraper No 40 83.6 65 0
Front End Loader No 40 79.1 65 0
Front End Loader No 40 79.1 65 0
Dump Truck No 40 76.5 65 0
Results
Calculated (dBA)
Equipment *Lmax Leq
Excavator 78.4 74.5
Excavator 78.4 74.5
Grader 82.7 78.7
Dozer 79.4 75.4
Scraper 81.3 77.3
Scraper 81.3 77.3
Front End Loader 76.8 72.9
Front End Loader 76.8 72.9
Dump Truck 74.2 70.2
Total 82.7 85.1
*Calculated Lmax is the Loudest value.

Item #8. Page 1417
Meeting Date: 1/24/2023 / Packet Page #: 1482
Roadway Construction Noise Model (RCNM),Version 1.1
Report date: 8/20/2018
Case Description: Silent Ranch - Bld Construct
---- Receptor #1 ----
Baselines (dBA)
Description Land Use Daytime Evening Night
Closest Residence Residential 55 50 45
Equipment
Spec Actual Receptor Estimated
Impact Lmax Lmax Distance Shielding
Description Device Usage(%) (dBA) (dBA) (feet) (dBA)
Crane No 16 80.6 20 0
Man Lift No 20 74.7 20 0
Man Lift No 20 74.7 20 0
Man Lift No 20 74.7 20 0
Generator No 50 80.6 20 0
Backhoe No 40 77.6 20 0
Backhoe No 40 77.6 20 0
Backhoe No 40 77.6 20 0
Welder / Torch No 40 74 20 0
Results
Calculated (dBA)
Equipment *Lmax Leq
Crane 88.5 80.6
Man Lift 82.7 75.7
Man Lift 82.7 75.7
Man Lift 82.7 75.7
Generator 88.6 85.6
Backhoe 85.5 81.5
Backhoe 85.5 81.5
Backhoe 85.5 81.5
Welder / Torch 82 78
Total 88.6 90.3
*Calculated Lmax is the Loudest value.

Item #8. Page 1418
Meeting Date: 1/24/2023 / Packet Page #: 1483
---- Receptor #2 ----
Baselines (dBA)
Description Land Use Daytime Evening Night
Accoustc Center - Closest Res. Residential 55 50 45
Equipment
Spec Actual Receptor Estimated
Impact Lmax Lmax Distance Shielding
Description Device Usage(%) (dBA) (dBA) (feet) (dBA)
Crane No 16 80.6 65 0
Man Lift No 20 74.7 65 0
Man Lift No 20 74.7 65 0
Man Lift No 20 74.7 65 0
Generator No 50 80.6 65 0
Backhoe No 40 77.6 65 0
Backhoe No 40 77.6 65 0
Backhoe No 40 77.6 65 0
Welder / Torch No 40 74 65 0
Results
Calculated (dBA)
Equipment *Lmax Leq
Crane 78.3 70.3
Man Lift 72.4 65.4
Man Lift 72.4 65.4
Man Lift 72.4 65.4
Generator 78.4 75.3
Backhoe 75.3 71.3
Backhoe 75.3 71.3
Backhoe 75.3 71.3
Welder / Torch 71.7 67.7
Total 78.4 80.1
*Calculated Lmax is the Loudest value.

Item #8. Page 1419
Meeting Date: 1/24/2023 / Packet Page #: 1484
Roadway Construction Noise Model (RCNM),Version 1.1
Report date: 8/20/2018
Case Description: Silent Ranch - Paving
---- Receptor #1 ----
Baselines (dBA)
Description Land Use Daytime Evening Night
Closest Residence Residential 55 50 45
Equipment
Spec Actual Receptor Estimated
Impact Lmax Lmax Distance Shielding
Description Device Usage(%) (dBA) (dBA) (feet) (dBA)
Paver No 50 77.2 20 0
Paver No 50 77.2 20 0
Grader No 40 85 20 0
Grader No 40 85 20 0
Roller No 20 80 20 0
Roller No 20 80 20 0
Results
Calculated (dBA)
Equipment *Lmax Leq
Paver 88.5 80.6
Paver 82.7 75.7
Grader 82.7 75.7
Grader 82.7 75.7
Roller 88.6 85.6
Roller 85.5 81.5
Total 88.6 90.3
*Calculated Lmax is the Loudest value.

Item #8. Page 1420
Meeting Date: 1/24/2023 / Packet Page #: 1485
---- Receptor #2 ----
Baselines (dBA)
Description Land Use Daytime Evening Night
Accoustc Center - Closest Res. Residential 55 50 45
Equipment
Spec Actual Receptor Estimated
Impact Lmax Lmax Distance Shielding
Description Device Usage(%) (dBA) (dBA) (feet) (dBA)
Paver No 50 77.2 65 0
Paver No 50 77.2 65 0
Grader No 40 85 65 0
Grader No 40 85 65 0
Roller No 20 80 65 0
Roller No 20 80 65 0
Results
Calculated (dBA)
Equipment *Lmax Leq
Paver 74.9 71.9
Paver 74.9 71.9
Grader 82.7 78.7
Grader 82.7 78.7
Roller 77.7 70.7
Roller 77.7 70.7
Total 82.7 83.1
*Calculated Lmax is the Loudest value.

Item #8. Page 1421
Meeting Date: 1/24/2023 / Packet Page #: 1486
Appendix G
Utility Studies and Will Serve Letters
Item #8. Page 1422
Meeting Date: 1/24/2023 / Packet Page #: 1487
Item #8. Page 1423
Meeting Date: 1/24/2023 / Packet Page #: 1488

TECHNICAL MEMORANDUM
TO: Steve Patton, City of Glendora
Alan Chou, DreamLand Investments, LLC

FROM: Stetson Engineers Inc.

SUBJECT: Water System Improvements
New Development – Tract 72413
JOB NO.: 2716
DATE: October 17, 2019
The City of Glendora (City) and DreamLand Investments, LLC (DreamLand), have jointly requested that Stetson Engineers Inc. (Stetson) review and determine the water system improvements necessary for the City to serve DreamLand’s proposed new development in Tract 72413. This Technical Memorandum provides a summary of Stetson’s review and recommendations for Tract 72413. Stetson’s review does not include potential future water supplies for any nearby future developments.

Project Background
The Tract 72431 development will be located on approximately 12 acres of largely undeveloped land north of Palm Drive near Grand Avenue and will consist of 12 new lots for single-family homes and one existing home with an expected home area of up to 6,000 square feet each.

Figure 1 provides an overview of the proposed new development and the City’s existing storage reservoirs and hydro-pneumatic system for water supply. Figure 2 is a Preliminary Site Development Plan showing lot numbers and proposed grading for the new development. The pad elevations of the proposed lots in the new development range from 950 feet to 1090 feet above mean sea level (amsl).

Existing Water System
In the vicinity of the new development, the City has two existing pressure zones (Zone 5 and Zone 11) that serve the existing community.

Item #8. Page 1424
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2 Zone 5
The City’s existing Zone 5 covers approximately 87 acres north of Sierra Madre Avenue.

Zone 5 operates off of the Hook Canyon Tanks located at an elevation of 1,174.5 feet amsl with a high water elevation of 1196.5 feet amsl. The Hook Canyon Tanks have a total storage capacity of 660,000 gallons.

Zone 11
Zone 11 is located along the northern boundary of Zone 5 at the end of Silent Ranch Drive and covers approximately 3 acres of single family estate land use that require higher pressures than can be supplied by Zone 5. Zone 11 is served by a hydropneumatic system that is over 30 years old. Water from Zone 5 is pumped using two booster pumps (one duty pump and one standby pump) at the Silent Ranch Pump Station to the hydro-pneumatic tank to serve Zone 11. The hydro-pneumatic tank is located at an elevation of approximately 1,115 feet amsl. Each booster pump has a capacity of 180 gallons per minute (gpm) and the hydro-pneumatic tank is set to provide water system pressures between 65 and 90 pounds per square inch (psi).

Zone 11 serves the following five existing properties (see Figure 1):
 935 N. Silent Ranch Drive (existing home)
 940 N. Silent Ranch Drive (existing home)
 945 N. Silent Ranch Drive (empty lot)
 950 N. Silent Ranch Drive (existing home – Lot 1 of Tract 72431)  960 N. Silent Ranch Drive (existing home)
Water System Requirements
Three key components of water supply are quantity, pressure, and quality. In addition, the requirements for domestic water supply differ from requirements for fire flows. The water system requirements for domestic supply and fire flows are summarized below.

Domestic Supply
The City’s 2015 Urban Water Management Plan (UWMP) details the 2015 Interim Urban Water Use Target of 245 gallons per capita per day (GPCD). This is considered the average domestic water use which is multiplied by a factor of 1.76 to obtain the maximum day demand and the maximum day demand is multiplied by a factor of 1.41 to obtain the peak hour demand. Based on these factors and assuming on average that 4 people live in each home, the calculated peak hour demand for a home is estimated to be 100 gallons per hour (=245 x 4 x 1.76 x 1.41 / 24). In addition, the City’s goal is to supply homes with a minimum pressure of 50 psi at the street meter.

Fire Flows
With regards to fire flows, the 2016 California Building Code (CBC) requires a minimum fire flow residual pressure of 20 psi and fire flow rate of 2,000 gpm for 2 hours (assuming flammable construction materials, i.e. wood framed homes – CBC B.102 and Table B105.1(2)). In addition, since the new development is in a Very High Fire Hazard Severity Zone, an additional fire flow of 500 gpm is required (per LA County Code

20.16.060). Therefore, a total fire flow of 2,500 gpm is necessary. The fire flow requirements and required locations of fire hydrants should be verified with local fire authorities.

Water Quality
Water quality for the City’s water distribution system is monitored and maintained by the City. Good circulation and turnover of water in the system are key for maintaining good Item #8. Page 1425
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3 water quality throughout the distribution system. Areas of concern are typically found where there are “dead ends” that have low circulation and large storage tanks with little circulation or turnover. Distribution systems that promote good circulation are preferred.

Proposed Water Supply Configuration for New Development Water supply for the new development is largely dictated by the topography and elevations of each proposed new home. Zone 5 is able to provided static pressures at or above the City’s minimum house pressure (50 psi) for all the proposed new lots except lots 1, 2, and 3.

However, Zone 11 is able to provide over 50 psi to lots 1, 2, and 3. Table 1 provides a summary of the elevations of each proposed new home along with the estimated domestic static water pressures that could be provided from extensions of either Zone 5 or Zone 11. Static pressures are not shown for Zone 11 where Zone 5 is able to meet the minimum required static pressure (50 psi). Since domestic flow rates are relatively low and the new development is close to Zones 5 and 11, the pressure losses from pipe friction losses is considered to be negligible.

Table 1 – Estimated Static Water Pressures.

Lot #
Elev
(ft
amsl)
Zone 5
Minimum Static
Pressure
(psi)
Zone 11
Minimum Static
Pressure
(psi)
1 1,080 41.4 75.2
2 1,090 37.1 70.8
3 1,070 45.7 79.5
4 Private Street
5 1,040 58.7 **
6 1,020 67.4 **
7 1,050 54.4 **
8 1,050 54.4 **
9 1,030 63.1 **
10 1,010 71.7 **
11 990 80.4 **
12 980 84.7 **
13 960 93.4 **
14 950 97.7 **
** Static pressures are not shown for Zone 11 where
Zone 5 is able to meet the minimum required static
pressure (50 psi).

Depending on the configuration of existing Zone 11 piping (which should be confirmed during design), it is anticipated that a 1.5-inch diameter pipe will be necessary to convey the domestic water supply for Zone 11 to Lots 1, 2, and 3.

Fire flows and pressures for the new development need to be evaluated differently than domestic flows since pressure losses are significant during the high fire flow rates (2,500 gpm).

Zone 11 does not have the flow capacity to meet the required fire flows, however, Zone 5 has sufficient flow capacity and the Hook Canyon reservoirs have sufficient storage capacity to provide the volume of fire flow required (i.e. 300,000 gal = 2,500 gpm x 120 min). Using the City’s existing hydraulic model for the City’s water distribution system, Stetson ran several Item #8. Page 1426
Meeting Date: 1/24/2023 / Packet Page #: 1491
4 scenarios to determine if Zone 5 is able to provide the maximum day demand and minimum fire flow rate (2,500 gpm) at the minimum pressure (20 psi) through fire hydrants at the new development. Based on the hydraulic modeling, Stetson determined that a 10-inch diameter pipeline looped system feeding the new development from the existing 10-inch pipeline in Palm Drive and from the existing 12-inch pipeline adjacent to the existing hydro pneumatic tank would be able to provide maximum day demand and 2,500 gpm fire flow at 39 psi at the top of the culde-sac in the new development (elev. 1070). As shown in Table 1, the proposed 10-inch diameter pipeline will have sufficient pressure to also serve the domestic water demands of lots 5 through 14. The looped piping configuration also provides good circulation which promotes good water quality through the new development. Figure 3 shows a proposed alignment for this new 10-inch water main. The proposed alignment will require coordination between the City and DreamLand to provide easements for the new water supply piping for the new development.

The proposed 10-inch diameter pipeline will not provide the desired 50 psi for domestic water service to lots 1, 2, and 3. The existing hydro-pneumatic tank system can provide the desired pressure to lots 1, 2, and 3, however, the system is over 30 years old and should be replaced to provide reliable domestic water service to the existing homes and the proposed new homes on lots 2 and 3.

Alternatively, domestic water supply for lots 1, 2, and 3 could be served from a new gravity-fed system consisting of a storage tank constructed at an elevation of 1,210 feet along with booster pumps to convey flows from Zone 5 to the new storage tank. This gravity-fed system was not evaluated further due to the much higher cost of planning, design, and construction of a new tank and access road in the vicinity immediately north of the new development.

Estimated Costs for Water Supply for New Development
Based on the proposed water supply configuration discussed above, Stetson prepared an estimated cost for design and construction of the new pipelines and replacement of the existing hydro-pneumatic tank system (tank, pumps, foundation, electrical, controls, fencing, etc.) since it is over 30 years old and was originally designed and constructed by others. The estimated cost for design and construction of the Zone 5, new 10-inch pipeline is approximately $825,000.

The estimated cost for design and construction of the Zone 11, new hydro-pneumatic system and piping is approximately $191,000. The total estimated design and construction costs for providing water supply to Tract 72413 is approximately $1,016,000. Table 2 provides a breakdown of the estimated costs.

Conclusions and Recommendations
The following conclusions have been reached regarding the new development’s domestic and fire flow water supplies:

1. Adequate flow and pressure for domestic water supply for lots 5 through 14 can be supplied from Zone 5.

2. Adequate flow and pressure for domestic water supply for lots 1, 2, and 3 can be supplied from Zone 11.

3. Adequate flow and pressure for fire flows for all lots in Tract 72413 can be supplied from Zone 5 to new fire hydrants.

4. The estimated cost for design and construction to provide domestic and fire flow water supplies to Tract 72413 is approximately $1,016,000.

Item #8. Page 1427
Meeting Date: 1/24/2023 / Packet Page #: 1492
5 The following are Stetson’s recommendations for the new development’s domestic and fire flow water supplies:

1. Confirm new development’s fire flow requirements and locations of new fire hydrants with local fire authorities.

2. Design and construct a 10-inch diameter looped pipeline connected to Zone 5 as shown in Figure 3 to supply domestic water supply for lots 5 through 14 and fire flow for the new development’s fire hydrants.

3. Replace the Zone 11 hydro-pneumatic system (pumps, tank, and controls) to provide a reliable water delivery system for Zone 11 homes.

4. Design and construct piping (confirm 1.5 inch) from the Zone 11 hydro-pneumatic system to the new development’s lots 2 and 3.

Glendora Tract 72413 Water Supply - Tech Memo 101719
Item #8. Page 1428
Meeting Date: 1/24/2023 / Packet Page #: 1493
Item #8. Page 1429
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Item #8. Page 1434
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Item #8. Page 1435
Meeting Date: 1/24/2023 / Packet Page #: 1500
Table 2. Conceptual Level Cost Estimate 10/17/2019
Glendora Tract 72413 Water Supply
Item Description Units Quantity Unit Cost Total Cost

1.100 Zone 5 Pipeline

1.101 Mobilization LS 1 $ 25,000 $ 25,000

1.102 Furnish and Install 10‐inch DIP LF 2,000 $ 148 $ 296,000

1.103 Furnish and Install Fire Hydrant EA 2 $ 3,300 $ 6,600

1.104 Furnish and Install Service Laterals EA 10 $ 6,825 $ 68,300

1.105 Furnish and Install Air/Vac Valve EA 1 $ 2,599 $ 2,600

1.106 Tie‐in to Existing EA 2 $ 10,000 $ 20,000

1.107 Sawcut Asphalt LF 1,160 $ 2 $ 2,100

1.108 Demo Concrete Driveway SY 444 $ 16 $ 7,000

1.109 Disposal of Asphalt, Concrete, etc. CY 90 $ 13 $ 1,200

1.110 Restore Asphalt Driveway LF 580 $ 115 $ 66,700

1.111 Replace Concrete Driveway SF 4,000 $ 6 $ 24,600

1.112 Restore Landscaping SF 1,600 $ 5 $ 8,000

1.113 Subtotal Zone 5 Pipeline $ 528,000

1.114 Contingency 25% $ 132,000

1.115 Subtotal with Contingency $ 660,000

1.116 Admin and Permitting 5% $ 33,000

1.117 Design 10% $ 66,000

1.118 Construction Management 10% $ 66,000

1.119 Total Zone 5 Pipeline $ 825,000

1.200 Zone 11 Hydro‐Pneumatic System Replacement and Pipeline

1.201 Mobilization LS 1 $ 6,000 $ 6,000

1.202 Furnish and Install 1.5‐inch Galv. Steel (installed with 10" pipe)
LF 1,150 $ 25 $ 28,800

1.203 Furnish and Install Service Laterals EA 2 $ 6,825 $ 13,700

1.204 Furnish and Install 3000 gal Hydro‐Pneumatic Tank EA 1 $ 29,500 $ 29,500

1.205 Furnish and Install Booster Pumps (180 gpm) EA 2 $ 4,132 $ 8,300

1.206 Furnish and Install Concrete Foundation LS 1 $ 2,950 $ 3,000

1.207 Furnish and Install Electrical/Controls LS 1 $ 25,000 $ 25,000

1.208 Furnish and Install Site Piping, Valves, Appurtenances LS 1 $ 5,000 $ 5,000

1.209 Furnish and Install Fencing/Security LS 1 $ 3,000 $ 3,000

1.210 Subtotal Zone 11 Hydro‐Pneumatic System Replacement and Pipeline $ 122,000

1.211 Contingency 25% $ 31,000

1.212 Subtotal with Contingency $ 153,000

1.213 Admin and Permitting 5% $ 8,000

1.214 Design 10% $ 15,000

1.215 Construction Management 10% $ 15,000

1.216 Total Zone 11 Hydro‐Pneumatic System Replacement and Pipeline $ 191,000 GRAND TOTAL $ 1,016,000
Stetson Engineers, Inc. Page 1 of 1 Glendora Tract 72413 ‐ Cost Estimate 101719 Item #8. Page 1436
Meeting Date: 1/24/2023 / Packet Page #: 1501
 Page 1 of 2
Memo
To: CITY OF GLENDORA
Attn.: Thomas Lambertson
Date: 3/26/18 – updated 11-19-2019
Re: brief on sanitary sewer service for Tentative Tract Map No. 72413, City of Glendora, County of Los Angeles Tentative Tract No. 72413 proposes to create 13 single family residential lots at the northerly terminus of Grand Ave., City of Glendora, CA. This is a custom lot subdivision, hence there are no building plans available at this time. It is expected that the home plans will average 5 bedrooms and 4 baths.

The proposed development is located within the jurisdictional boundaries of LA Co. Sanitation District No. 22. The wastewater flow originating from 13 of the proposed lots will discharge into an existing local sewer line in Palm Drive for conveyance down Grand Ave. To the District’s Baseline Trunk Sewer. Lot No. 1 of this development has an existing home which is connected to the local sewer line in Silent Ranch Drive.

It should be noted that in 2015, a sewer capacity study was prepared for Tract No. 70622, which is located on the west side of Grand Ave., just south of Sierra Madre Ave., or about 800 ft. south of the proposed development. The line analyzed in that study is the same local line that the proposed subdivision is connecting to. Flow tests for that study were conducted at Grand Ave. And Richardson Lane. That study concluded the Post-Development Qpeak flow to be 0.48 cfs. The available capacity for that local line, at that point, is 1.93 cfs.

Based upon the above mentioned study, the local line in Grand Ave. is currently flowing at about 25% of peak flow capacity (half-full). A copy of said Study is available upon request.

The addition of 13 new homes will increase the flows within the existing system by 0.02 cfs to a total of 0.50cfs which is only 26% of the capacity of the pipe. Please refer to the attached calculations demonstrating this increase.

Submitted with this brief is a copy of the tentative tract map and a copy of the preliminary site development plan. The site plan depicts the future 8 in. Sewer main extension that will service the future 13 single family homes. This proposed line will connect to the existing 8-inch local line in Palm Drive.

Giron Engineers, Inc.

Item #8. Page 1437
Meeting Date: 1/24/2023 / Packet Page #: 1502
 Page 2 of 2
Flow Capacity Analysis:

References:

A. Approved Sewer Capacity Study for Tract No. 70622 (on file at City of Glendora, copy available upon request)
B. L.A. Co. DPW Table of Estimated Average Daily Sewage Flows for Various Occupancies (attached)
Note: per City & County requirements, the sewer pipe is considered at full capacity when it is flowing half full.
 Available sewer pipe capacity (ref. A): 1.93 cfs
 Existing current condition (ref. A): 0.48 cfs
 Estimated Additional flow from proposed development:
 Number of new homes = 13
 Estimated average daily sewage flow for 3 bedroom
or more dwelling unit (ref. B) = 300 gal/D.U.
 Peak flow multiplier (ref. B) = 2.5
 Total estimated additional sewer flow = 13 x 300 x 2.5 = 9750 gal/day = 0.02 cfs  QPEAK AFTER DEVELOPMENT = 0.48 + 0.02 = 0.50 CFS

0.50 cfs << 1.93 cfs
Peak flow will be 26% of full capacity 
Item #8. Page 1438
Meeting Date: 1/24/2023 / Packet Page #: 1503
Occupancy Abbreviation *Average daily flow
Apartment Buildings:

Bachelor or Single dwelling units Apt 150 gal/D.U.
1 bedroom dwelling units Apt 200 gal/D.U.
2 bedroom dwelling units Apt 250 gal/D.U.
3 bedroom or more dwelling units Apt 300 gal/D.U.

Auditoriums, churches, etc. Aud 5 gal/seat
Automobile parking P 25 gal/1000 sq ft gross floor area Bars, cocktails lounges, etc. Bar 20 gal/seat
Commercial Shops & Stores CS 100 gal/1000 sq ft gross floor area Hospitals (surgical) HS 500 gal/bed
Hospitals (convalescent) HC 85 gal/bed
Hotels H 150 gal/room
Medical Buildings MB 300 gal/1000 sq ft gross floor area Motels MB 150 gal/unit
Office Buildings Off 200 gal/1000 sq ft gross floor area Restaurants, cafeterias, etc. R 50 gal/seat
Schools:

Elementary or Jr. High S 10 gal/student
High Schools HS 15 gal/student
Universities or Colleges U 20 gal/student
College Dormitories CD 85 gal/student
Zone Coefficient (cfs/Acre)
Agriculture ---------------------------------- 0.001
Residential*:

R-1 -------------------------------------------- 0.004
R-2 -------------------------------------------- 0.008
R-3 -------------------------------------------- 0.012
R-4 -------------------------------------------- 0.016* Commercial:

C-1 through C-4 ---------------------------- 0.015*
Heavy Industrial:

M-1 through M-4 -------------------------- 0.021*
exceed the coefficients shown
* Use 0.001 (cfs/unit) for condominiums only
Estimated Average Daily Sewage Flows for Various Occupancies *Multiply the average daily flow by 2.5 to obtain the peak flow Zoning Coefficients
* Individual building, commercial or industrial plant capacities shall be the determining factor when they Item #8. Page 1439
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Item #8. Page 1440
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Item #8. Page 1441
Meeting Date: 1/24/2023 / Packet Page #: 1506
Appendix H
Intersection Safety Assessment
Item #8. Page 1442
Meeting Date: 1/24/2023 / Packet Page #: 1507
Item #8. Page 1443
Meeting Date: 1/24/2023 / Packet Page #: 1508

INTERSECTON SAFETY ASSESSMENT
Intersection of Grand Avenue and Palm Avenue
Tentative Tract No. 72413
Glendora, CA
PLN14-0014
PREPARED FOR:

Alison Sweet, PE
Director of Public Works/City Engineer
Department of Public Works

CITY OF GLENDORA
116 East Foothill Blvd.

Glendora, CA 91740
PREPARED BY:

STEVEN ITAGAKI, PE, TE, PTOE
City of Glendora Traffic Engineering Consultant
JMDiaz, Inc. (JMD)
18645 East Gale Avenue, Suite 212
City of Industry, CA 91748-1363
June 20, 2020
Item #8. Page 1444
Meeting Date: 1/24/2023 / Packet Page #: 1509
Grand Ave / Palm Dr Intersection Safety Assessment
Site Improvement Suggestions (see attached exhibit):
- Relocate existing stop sign and street name sign onto a new taller post. The bottom section of the stop sign is currently 5.5’ above sidewalk grade. The vertical clearance of all signs (per CA MUTCD) should be 7’ minimum.
- Repaint red curb on the west side of Grand Avenue where the street narrows to 18’ in width.
- Upgrade the existing street light on wood pole at the intersection to LED. - Relocate Speed Limit (25) sign onto the existing street light. Currently, the speed limit sign is obscured behind the street light pole. Remove sign post. - After reviewing the site plans from the developer, ensure sidewalk fronting the development are cleared from trees/debris. Include curb ramps on the north and south sides of the intersection.
- Add 50’ red curb on the south side of Palm Drive starting at the BCR. - Repaint Stop Legend and Stop Bar.

Sight Distance Assessment (see attached exhibits):
- Per Chapter 200 of the Highway Design Manual (HDM), the recommended stopping sight distance for 25 mph is 150 feet.
- The intersection approach sight distance for both northbound Grand Avenue and eastbound Palm Drive meet the sight distance requirements. - Eastbound Palm Drive onto southbound Grand Avenue has an existing tree partially obscuring the sight lines at the stop bar. However, as a vehicle creeps forward, sight distance is clear.

Accident History:
- There are a total of two collisions within this vicinity in the past five years. However, only one accident at the intersection.
- Thus, based on accidents, there are no safety issues requiring mitigation.

Item #8. Page 1445
Meeting Date: 1/24/2023 / Packet Page #: 1510
Palm Drive
INSTALL 50' OF NEW RED CURB
STRIPING NOTES:
1 2
3 REPAINT EXISTING RED CURB
REPAINT "STOP" LEGEND & LIMIT LINE
R RELOCATE EXISTING R1-1 & STREET NAME SIGN ADD CURB RAMPS FOLLOWING CITY STANDARDS 40'
40'
18'Grand Avenue
SIGNING NOTES:

S RELOCATE EXISTING R2-1(25) SIGN ONTO
C
STREET IMPROVEMENT NOTES:

ONTO NEW POST THAT WILL PROVIDE 7' VERTICAL

CLEARANCE TO BOTTOM OF SIGN

U UPGRADE STREET LIGHT TO LED
E EXISTING R28(S)(CA) SIGN

STREET LIGHT POLE
Item #8. Page 1446
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Appendix I
City VMT Calculator
Item #8. Page 1454
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Item #8. Page 1455
Meeting Date: 1/24/2023 / Packet Page #: 1520
CEQA Transportation Analysis Screening Tool for Development Projects Legend
User Input xxxx
Calculated Value xxxx
1 Project Information
Applicant Name
Project Name
Number Street (no street suffix, e.g. Ave., Blvd.)
Address 950
2 Project Description
Type Unit Existing Project Change
Emploment - Office Building 1000s Sq Feet - Library No
Employment - Hospital 1000s Sq Feet - School No
Employment - Medical/Dental Office 1000s Sq Feet - Park No Employment - Movie Theater 1000s Sq Feet - Community Center No Hotel Rooms - Other locally serving No
Industrial - Heavy 1000s Sq Feet -
Industrial - Light 1000s Sq Feet -
Industrial - Warehouse 1000s Sq Feet -
Retail - Store 1000s Sq Feet -
Retail - Restaurant 1000s Sq Feet -
Residential - Apartment Units -
Residential - Assisted Living Beds -
Residential - Single Family Units 1 12 11
Residential - Townhouse Units -
Number of Affordable Housing Units Units -
3 Checklist Screening
Screened to be Presumed as Less Than Significant? Yes Project Below Size Threshold 4 Threshold Estimate
If not screened, would the Proposed Project have VMT that is Less than the Thresholds of Significance? Threshold VMT Project Est.

Residential VMT No 19.3 23.7
Employment VMT - 24.5 -
If "No" for either, the following Potential Mitigation Measures could be implemented to reduce to less than significant 5 Mitigation Measures
Strategy Implementation Number VMT Reductions
On-Site Bikeshare Yes 10 Residential Employment
Unbundled Parking Costs Yes (1.4) -
Neighborhood Electric Vehicle
Infrastructure Yes 10
Provide Parking Cash-Out Program Yes
TDM Information >25 ksft non-residential
Yes
Preferential Parking >50 ksft non-residential Yes
Multimodal Site Improvements >100 ksft non-residential Yes Implement Transportation Demand
Management Program – Required
Implementation/Monitoring Yes
Implement Subsidized or Discounted
Transit Program Yes
Telecommuting and Alternative Work
Schedules Yes
Fair Share contribution to First/Last Mile
project or other intrastructure Yes Threshold VMT Project Est.

Residential 19.3 22.3
Presumed Less Than Significant CEQA Transportation Impact After Mitigation Yes Employment 24.5 - 5 This tool is to estimate the potential of a land use
development project, where the City of Glendora is the
CEQA lead agency
Install electrical charging equipment
Separates parking cost from property
costs
Implement bikeshare program
To support non-vehicle trips
Encouraging telecommuting and
alternative work schedules reduces the
Encourage transit use by providing
subsidy
Reduce drive-alone travel mode share and
encourage alternative modes of travel
Incentives for alternative transportation
950 Silent Ranch Drive

SILENT RANCH
Is this project a:

Purpose
Item #8. Page 1456
Meeting Date: 1/24/2023 / Packet Page #: 1521
Item #8. Page 1457
Meeting Date: 1/24/2023 / Packet Page #: 1522
Comment Letter F1
In Reply Refer to:

FWS-LA-22-0068834-CEQA
August 4, 2022
Sent Electronically
Mark Carnahan
City Planner
Community Development Department
City of Glendora
116 E. Foothill Boulevard
Glendora, California 91741
Subject: Comments on the Initial Study/Mitigated Negative Declaration for the Grand Estates Residential Subdivision Project, City of Glendora, Los Angeles County, California Dear Mark Carnahan:

The U.S. Fish and Wildlife Service (Service) has reviewed the Notice of Intent (NOI) to Adopt a Mitigated Negative Declaration for the Grand Estates Residential Subdivision Project in the City of Glendora (City), California. The comments provided in this letter are based on information provided in the NOI, the project’s Initial Study/Mitigated Negative Declaration (IS/MND; Dudek 2022a), the project’s Biological Resources Technical Report (BRTR; Dudek 2022b), and our knowledge of sensitive and declining species and habitats.

The primary concern and mandate of the Service is the protection of public fish and wildlife resources and their habitats. The Service has legal responsibility for the welfare of migratory birds, anadromous fish, and endangered animals and plants occurring in the United States. The Service is also responsible for administering the Federal Endangered Species Act of 1973 (Act), as amended (16 U.S.C. 1531 et seq.), including habitat conservation plans (HCP) developed under section 10(a)(l) of the Act.

PROJECT DESCRIPTION
The project is located on privately owned land at 950 North Silent Ranch Drive in the City of Glendora in the San Gabriel Mountain foothills. The project involves a proposed subdivision of a 27-acre hillside property for the development of a gated single-family residential community.

About 11 acres of the southern portion of the property would be subdivided into 14 lots, with one lot for an existing residential house, 12 lots expected to be developed in the future with custom homes, and one additional lot for two private streets that will have a single public street access from Palm Drive. The subdivision would include one 16-acre parcel at the northern section of the site to be held as open space with exception of the three existing flood control structures that are to be removed and reconstructed to provide protection from stormwater debris flows and F1-1
F1-2
F1-3
Item #8. Page 1458
Meeting Date: 1/24/2023 / Packet Page #: 1523

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Glendora City CouncilJanuary 24, 2023

Glendora City Council
January 24, 2023