Agenda packet — Rancho Mirage City Council, November 6, 2025 (part 6 of 8)

California Fish and Wildlife Code, Section 3503.5
Under the California Fish and Wildlife Code, Section 3503.5, it is unlawful to take, possess, or destroy any birds in the order Falconiformes (hawks, eagles, and falcons) or Strigiformes (owls).

Take would include the disturbance of an active nest resulting in the abandonment or loss of young.

Migratory Bird Treaty Act
The federal Migratory Bird Treaty Act (MBTA) prohibits the taking, hunting, killing, selling, purchasing, etc. of migratory birds, parts of migratory birds, or their eggs and nests. As used in the MBTA, the term "take" is defined as "to pursue, hunt, shoot, capture, collect, kill, or attempt to pursue, hunt, shoot, capture, collect, or kill, unless the context otherwise requires." Most bird species native to North America are covered by this act.

Sensitive Natural Communities
The California Office of Planning and Research and the Office of Permit Assistance (1986) define project effects that substantially diminish habitat for fish, wildlife, or plants, or that disrupt or divide the physical arrangement of an established community as significant impacts under CEQA. 1175

This definition applies to certain natural communities because of their scarcity and ecological values and because the remaining occurrences are vulnerable to elimination. For this study, the term "sensitive natural community" includes those communities that, if eliminated or substantially degraded, would sustain a significant adverse impact as defined under CEQA. Sensitive natural communities are important ecologically because their degradation and destruction could threaten populations of dependent plant and wildlife species and significantly reduce the regional distribution and viability of the community. If the number and extent of sensitive natural communities continue to diminish, the status of rare, threatened, or endangered species could become more precarious, and populations of common species (i.e., not special status species) could become less viable. Loss of sensitive natural communities also can eliminate or reduce important ecosystem functions, such as water filtration by wetlands and bank stabilization by riparian woodlands for example.

Protected Plants
The California Desert Native Plant Act was passed in 1981 to protect non -listed California desert native plants from unlawful harvesting on both public and privately -owned lands. Harvest, transport, sale, or possession of specific native desert plants is prohibited unless a person has a valid permit. The following plants are under the protection of the California Desert Native Plants Act:
• Dalea spinosa (smoketree)
• All species of the genus Prosopis (mesquites)
• A11 species of the family Agavaceae (century plants, nolinas, yuccas) • All species of Cactus
• Creosote Rings, ten feet in diameter or greater
• All Joshua Trees
The project would be required to comply with the County of San Bernardino Desert Native Plant Protection Ordinance. The removal of any trees listed under Section 88.01.060 would be required to comply with Section 88.01.050, which requires the project applicant to apply for a Tree or Plant Removal Permit prior to removal from the project site.
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APPENDIX C

CULTURAL RESOURCE ASSESSMENT
16 LOT SUBDIVISION PROJECT

ON PETERSON ROAD
Assessor's Parcel Nos. 689-090-003, 689-130-004, -005, -013, -014, -and 017 and 689-140-022 City of Rancho Mirage, Riverside County, California
For Submittal to:

Development Services Department, Planning Division
City of Rancho Mirage
69-825 Highway 111
Rancho Mirage, CA 92270
Prepared for:

Horti Caesaris, LLC
9401 Wilshire Blvd, 9th Floor
Beverly Hills, CA 90212
Prepared by:

CRM TECH
1016 East Cooley Drive, Suite A/B
Colton, CA 92324
Bai "Tom" Tang, Principal Investigator
Michael Hogan, Principal Investigator
March 25, 2024
CRM TECH Contract No. 4085
1177

Cultural Resource Assessment

CRM TECH
Title:

Authors:

Consulting Firm:

Date:

For Submittal to:

Prepared for:

Project Size:

USGS
Quadrangle:

Keywords:

Cultural Resource Assessment: 16 Lot Subdivision Project on Peterson Road; Assessor's Parcel Nos. 689-090-003, 689-130- 004, -005, -013, -014, and -017, and 689-140-022, City of Rancho Mirage, Riverside County, California
Frank Raslich, Archaeologist/Report Writer
Michael Hogan, Principal Investigator

CRM TECH
1016 East Cooley Drive, Suite A/B
Colton, CA 92324
(909) 824-6400
March 25, 2024
Development Services Department, Planning Division
City of Rancho Mirage
69-825 Highway 111
Rancho Mirage, CA 92270
(760) 328-2266
Konstantinos Patis
Horti Caesaris, LLC
9401 Wilshire Blvd, 9th Floor
Beverly Hills, CA 90212
+30-21-08128242
Approximately 19.8 acres
Cathedral City, Calif., 7.5' quadrangle (Section 2, T5S R5E, San Bernardino Baseline and Meridian)
Coachella Valley, western Colorado Desert; Phase I cultural resource assessment; no "historical resources" under CEQA 1178

Cultural Resource Assessment

CRM TECH

EXECUTIVE SUMMARY
Between December 2023 and March 2024, at the request of Horti Caesaris, LLC, CRM TECH performed a cultural resources survey on approximately 19.8 acres of undeveloped land in the City of Rancho Mirage, Riverside County, California. The subject property of the study consists of Assessor's Parcel Nos. 689-090-003, 689-130- 004, -005, -013, -014, and -017 and 689-140-022, located on both the east and west sides of Peterson Road, north of Mirage Cove Drive, and south of the Whitewater River, in the northwest quarter of Section 2, Township 5 South, Range 5 East, San Bernardino Baseline and Meridian.

The study is part of the environmental review process for a proposed 16 -lot subdivision project. The City of Rancho Mirage, as the lead agency for the project, required the study in compliance with the California Environmental Quality Act (CEQA). The purpose of the study is to provide the City with the necessary information and analysis to determine whether the project would cause substantial adverse changes to any "historical resources," as defined by CEQA, that may exist in or around the project area.

To identify such resources, CRM TECH conducted a historical/archaeological resources records search, initiated a Native American Sacred Lands File search, contacted pertinent Native American representatives, pursued historical background research, and carried out an intensive -level field survey. Throughout the various avenues of research, this study did not encounter any "historical resources" within or adjacent to the project area. Therefore, CRM TECH recommends to the City of Rancho Mirage a finding of No Impact regarding "historical resources." No further cultural resources investigation is recommended for the project unless development plans undergo such changes as to include areas not covered by this study.

However, if buried cultural materials are encountered during any earth -moving operations associated with the project, all work in that area should be halted or diverted until a qualified archaeologist can evaluate the nature and significance of the finds. 1179

Cultural Resource Assessment

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TABLE OF CONTENTS

EXECUTIVE SUMMARY
INTRODUCTION 1
SETTING 4
Current Natural Setting 4
Cultural Setting 5
Prehistoric Context 5
Ethnohistoric Context 5
Historic Context 7
RESEARCH METHODS 8
Records Search 8
Native American Participation 8
Historical Background Research 8
Field Survey 8
RESULTS AND FINDINGS 9
Records Search 9
Native American Participation 9
Historical Background Research 9
Field Survey 12
DISCUSSION 12
CONCLUSIONS AND RECOMMENDATIONS 13
REFERENCES 14
APPENDIX 1: Personnel Qualifications 16
APPENDIX 2: Native American Scoping Responses 20

LIST OF FIGURES
Figure 1. The project vicinity 1
Figure 2. The project area and vicinity on the USGS quadrangle 2 Figure 3. A recent satellite image showing the project area 3 Figure 4. Overview of the current natural setting of the project area 4 Figure 5. Previous cultural resources studies in the vicinity of the project area 10 Figure 6. The project area and vicinity in 1855-1856 11 Figure 7. The project area and vicinity in 1901 11
Figure 8. The project area and vicinity in 1941 11
Figure 9. The project area and vicinity in 1956-1958 11 1 1 0

Cultural Resource Assessment

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AN JACIN'TO

INTRODUCTION
Between December 2023 and March 2024, at the request of Horti Caesaris, LLC, CRM TECH performed a cultural resources survey on approximately 19.8 acres of undeveloped land in the City of Rancho Mirage, Riverside County, California (Figure 1). The subject property of the study consists of Assessor's Parcel Nos. 689-090-003, 689-130-004, -005, -013, -014, -017 and 689-140- 022, located on both the east and west sides of Peterson Road, north of Mirage Cove Drive, and south of the Whitewater River, in the northwest quarter of Section 2, Township 5 South, Range 5 East, San Bernardino Baseline and Meridian (Figures 2, 3).

The study is part of the environmental review process for a proposed 16 -lot subdivision project. The City of Rancho Mirage, as the lead agency for the project, required the study in compliance with the California Environmental Quality Act (CEQA; PRC §21000, et seq.). The purpose of the study is to provide the City with the necessary information and analysis to determine whether the project would cause substantial adverse changes to any "historical resources," as defined by CEQA, that may exist in or around the project area.

To identify such resources, CRM TECH conducted a historical/archaeological resources records search, initiated a Native American Sacred Lands File search, contacted pertinent Native American representatives, pursued historical background research, and carried out an intensive -level field survey. The following report is a complete account of the methods, results, and final conclusion of the study. Personnel who participated in the study are named in the appropriate sections below, and their qualifications are provided in Appendix 1.
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Figure 1. The project vicinity. (Based on the USGS Santa Ana, Calif., quadrangle [USGS 1979]) Ranbq' UGL
16 Lot Subdivision — Rancho Mirage
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Figure 2. The project area and vicinity. (Based on the USGS Cathedral City, Calif., 7.5' quadrangle [USGS 19811) 16 Lot Subdivision — Rancho Mirage
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Whitewater River
Project
area
Figure 3. A recent satellite image showing the project area. (Based on Google Earth imagery) 16 Lot Subdivision — Rancho Mirage
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SETTING

CURRENT NATURAL SETTING
The City of Rancho Mirage is located in the heart of the Coachella Valley, a northwest -southeast trending desert valley that constitutes the western end of the Colorado Desert. Dictated by this geographic setting, the climate and environment of the region are typical of the southern California desert country, marked by extremes in temperature and aridity. Temperatures in the region reach over 120 degrees Fahrenheit in summer, and dip to freezing in winter. Average annual precipitation is less than five inches, and the average annual evaporation rate exceeds three feet.

The project location is in the City of Rancho Mirage, in a rapidly urbanizing area near Highway 111.

The property is surrounded by residential neighborhoods of relatively recent vintages to the west, the Whitewater River on the north and east, and residential developments to the south. The terrain in the project area is generally level, with elevations ranging approximately from 313 to 330 feet above mean sea level. The surface soil is composed of light olive gray fine sand.

The project location is within what would be the California Creosote Bush Scrub plant community; however, the ground surface in the project area has been cleared of native vegetation in the past and existing vegetation include introduced and ruderal species such as landscaping plants and low-lying grasses (Figure 4).

Figure 4. Overview of the current natural setting of the project area. (January 19, 2024; view to the east) 16 Lot Subdivision — Rancho Mirage
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CULTURAL SETTING
Prehistoric Context
Numerous investigations on the history of cultural development in southern California have led researchers to propose a number of cultural chronologies for the desert regions. A specific cultural sequence for the Colorado Desert was offered by Schaefer (1994) on the basis of the many archaeological studies conducted in the area. The earliest time period identified is the Paleoindian (ca. 8,000 to 10,000-12,000 years ago), when "small, mobile bands" of hunters and gatherers, who relied on a variety of small and large game animals as well as wild plants for subsistence, roamed the region (Schaefer 1994:63). These small groups settled "on mesas and terraces overlooking larger washes" (Schaefer 1994:64). The artifact assemblage of that period typically consists of very simple stone tools, "cleared circles, rock rings, [and] some geoglyph types" (Schaefer 1994:64).

The Early Archaic Period follows and dates to ca. 8,000 to 4,000 years ago. It appears that a decrease in population density occurred at this time and that the indigenous groups of the area relied more on foraging than hunting. Very few archaeological remains have been identified to this time period. The ensuing Late Archaic Period (ca. 4,000 to 1,500 years ago) is characterized by continued low population densities and groups of "flexible" sizes that settled near available seasonal food resources and relied on "opportunistic" hunting of game animals. Stone grinding implements for food processing were prominent during this time period.

The most recent period in Schaefer's scheme, the Late Prehistoric, dates from ca. 1,500 years ago to the time of the Spanish missions and saw the continuation of the seasonal settlement pattern.

Peoples of the Late Prehistoric Period were associated with the Patayan cultural pattern and relied more heavily on the availability of seasonal "wild plants and animal resources" (Schaefer 1994:66).

It was during this period that ceramics and the bow and arrow were introduced into the region.

The shores of Holocene Lake Cahuilla, during times of its presence, attracted much settlement and resource procurement activities. In times of the lake's desiccation and absence, according to Schaefer (1994:66), the Native people moved away from its receding shores towards rivers, streams, and mountains. Numerous archaeological sites dating to the last high stand of Holocene Lake Cahuilla, roughly between 1600 and 1700 A.D., have been identified along its former shoreline.

Testing and mitigative excavations at these sites have recovered brown and buff ware ceramics, a variety of stone grinding tools and projectile point types, ornaments, and cremation remains.

Ethnohistoric Context
The Coachella Valley is a historical center of Native American settlement, where U.S. surveyors noted large numbers of Indian villages and rancherias, occupied by the Cahuilla people, in the mid - 19th century. The origin of the name "Cahuilla" is unclear, but may originate from their own word kawiya, meaning master or boss (Bean 1978). The Takic-speaking Cahuilla are generally divided by anthropologists into three groups, according to their geographic setting: the Pass Cahuilla of the San Gorgonio Pass -Palm Springs area, the Mountain Cahuilla of the San Jacinto and Santa Rosa Mountains and the Cahuilla Valley, and the Desert Cahuilla of the eastern Coachella Valley. The 16 Lot Subdivision — Rancho Mirage
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basic written sources on Cahuilla culture and history include Kroeber (1925), Strong (1929), and Bean (1978), based on information provided by such Cahuilla informants as Juan Siva, Francisco Patencio, Katherine Siva Saubel, and Mariano Saubel. The following ethnohistoric discussion is based primarily on these sources.

The Cahuilla did not have a single name that referred to an all-inclusive tribal affiliation. Instead, membership was in terms of lineages or clans. Each lineage or clan belonged to one of two main divisions of the people, known as moieties. Their moieties were named for the Wildcat, or Tuktum, and Coyote, or Istam. Members of clans in one moiety had to marry into clans from the other moiety. Individual clans had villages, or central places, and territories they called their own, for purposes of hunting game, and gathering raw materials for food, medicine, ritual, or tool use. They interacted with other clans through trade, intermarriage, and ceremonies.

Cahuilla subsistence was defined by the surrounding landscape and primarily based on the hunting and gathering of wild and cultivated foods, exploiting nearly all of the resources available in a highly developed seasonal mobility system. They were adapted to the arid conditions of the desert floor, the lacustral cycles of Holocene Lake Cahuilla, and the environments of the nearby mountains.

When the lake was full, or nearly full, the Cahuilla would take advantage of the resources presented by the body of fresh water, building elaborate stone fish traps. Once the lake had desiccated, they relied on the available terrestrial resources. The cooler temperatures and resources available at higher elevations in the nearby mountains were also taken advantage of.

The Cahuilla diet included seeds, roots, wild fruits and berries, acorns, wild onions, pifion nuts, and mesquite and screw beans. Medicinal plants such as creosote, California sagebrush, yerba buena and elderberry were typically cultivated near villages (Bean and Saubel 1972). Common game animals included deer, antelope, big horn sheep, rabbits, wood rats and, when Holocene Lake Cahuilla was present, fish and waterfowl. The Cahuilla hunted with throwing sticks, clubs, nets, traps, and snares, as well as bows and arrow (Bean 1978; CSRI 2002). Common tools included manos and metates, mortars and pestles, hammerstones, fire drills, awls, arrow -straighteners, and stone knives and scrapers. These lithic tools were made from locally sourced material as well as materials procured through trade or travel. They also used wood, horn, and bone spoons and stirrers; baskets for winnowing, leaching, grinding, transporting, parching, storing, and cooking; and pottery vessels for carrying water, storage, cooking, and serving food and drink (Bean 1978; CSRI 2002).

As the landscape defined their subsistence practices, the tending and cultivation practices of the Cahuilla helped shape the landscape. Biological studies have recently found evidence that the fan palms found in the Coachella Valley and throughout the southeastern California desert (Washingtonia filifera) may not be relics from a paleo-tropical environment, but instead a relatively recent addition brought to the area and cultivated by native populations (Anderson 2005). The planting of palms by the Cahuilla is well -documented, as is their enhancement of palm stands through the practice of controlled burning (Anderson 2005; Bean and Saubel 1972). Burning palm stands would increase fruit yield dramatically by eliminating pests such as the palm borer beetle, date scales, and spider mites (Bean and Saubel 1972). It also prevented out -of -control wildfires by eliminating dead undergrowth before it accumulated to dangerous levels. The Cahuilla also burned stands of chia to produce higher yields, and deergrass to yield straighter, more abundant stalks for basketry (Bean and Saubel 1972; Anderson 2005).
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Population data prior to European contact is almost impossible to obtain, but estimates range from 3,600 to as high as 10,000 persons covering a territory of over 2,400 square miles. During the 19th century, the Cahuilla population was decimated as a result of European diseases, most notably smallpox, for which the Native peoples had no immunity. Today, Native Americans of Pass or Desert Cahuilla heritage are mostly affiliated with one or more of the Indian reservations in and near the Coachella Valley, including Agua Caliente, Morongo, Cabazon, Torres Martinez, and Augustine.

There has been a resurgence of traditional ceremonies in recent years, and the language, songs, and stories are now being taught to the youngest generations.

Historic Context
In 1823-1825, Jose Romero, Jose Maria Estudillo, and Romualdo Pacheco became the first noted European explorers to travel through the Coachella Valley when they led a series of expeditions in search of a route to Yuma (Johnston 1987:92-95). Due to its harsh environment, few non -Indians ventured into the desert valley during the Mexican and early American periods, except those who traveled along the established trails. The most important of these trails was the Cocomaricopa Trail, an ancient Indian trading route that was "discovered" in 1862 by William David Bradshaw and known after that as the Bradshaw Trail (Gunther 1984:71; Ross 1992:25). In much of the Coachella Valley, this historic wagon road traversed a similar course to that of present-day State Route 111.

During the 1860s -1870s, the Bradshaw Trail served as the main thoroughfare between coastal southern California and the Colorado River, until the completion of the Southern Pacific Railroad in 1876-1877 brought an end to its heyday (Johnston 1987:185).

Non -Indian settlement in the Coachella Valley began in the 1870s with the establishment of railroad stations along the Southern Pacific Railroad and spread further in the 1880s after public land was opened for claims under the Homestead Act, the Desert Land Act, and other federal land laws (Laflin 1998:35-36; Robinson 1948:169-171). Farming became the dominant economic activity in the valley thanks to the development of underground water sources, often in the form of artesian wells. Around the turn of the century, the date palm was introduced into the Coachella Valley, and by the late 1910s dates were the main agricultural crop and the tree an iconic image celebrating the region as the "Arabia of America" (Shields Date Gardens 1957). Then, starting in the 1920s, a new industry featuring equestrian camps, resorts, hotels, and eventually country clubs began to spread throughout the Coachella Valley, transforming it into southern California's premier winter retreat.

In the Rancho Mirage area, the first notable settlement activities occurred in the 1910s -1920s, when several date ranches were established in the present-day city boundary (Love and Tang 1996:7). In 1924, R.P. "Bert" Davie and E.E. McIntyre subdivided the Rancho Rio del Sol Estates around today's Clancy Lane, creating a small community nicknamed "Little Santa Monica" (Love and Tang 1996:8). Ten years later, Louis Blankenhorn and Laurence Macomber began a new subdivision at the mouth of Magnesia Spring Canyon, and for the first time bestowed the name Rancho Mirage on the community (Love and Tang 1996:8). After the end of WWII, Rancho Mirage embarked on a period of rapid growth. With the development of the Thunderbird Country Club and the Tamarisk Country Club in 1951-1952, Rancho Mirage set the trend in the post -WWII boom among the five cove communities along Highway 111 (Love and Tang 1996:8-9). This trend has continued into the present and has given rise to the City of Rancho Mirage's popular reputation as the "country club city.
,,
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RESEARCH METHODS

RECORDS SEARCH
On January 9, 2024, CRM TECH archaeologist Nina Gallardo completed the historical/ archaeological resources records search for this study at the Eastern Information Center (EIC) of the California Historical Resources Information System. Located on the campus of the University of California, Riverside, the EIC is the official cultural resource records repository for the County of Riverside. The purpose of the records search was to compile a complete inventory of previously identified cultural resources and existing cultural resources reports within a one -mile radius of the project location. Previously identified cultural resources include properties designated as California Historical Landmarks, Points of Historical Interest, or Riverside County Historic Landmarks, as well as those listed in the National Register of Historic Places, the California Register of Historical Resources, or the California Historical Resources Inventory.

NATIVE AMERICAN PARTICIPATION
On December 21, 2023, CRM TECH submitted a written request to the State of California Native American Heritage Commission (NAHC) for a records search in the commission's Sacred Lands File. In the meantime, CRM TECH also contacted the nearby Agua Caliente Band of Cahuilla Indians (ACBCI) for additional information on potential Native American cultural resources in the project vicinity and to arrange for tribal participation in the upcoming archaeological field survey.

The responses from the NAHC and the ACBCI are summarized below and attached to this report in Appendix 2.

HISTORICAL BACKGROUND RESEARCH
Historical background research for this study was conducted by CRM TECH Archaeologist Frank Raslich. In addition to published literature in local and regional history, sources consulted during the research included U.S. General Land Office (GLO) land survey plat maps dated 1856, United States Geological Survey (USGS) topographic maps dated 1904-1988, and aerial/satellite photographs taken in 1959-2023. The historical maps are available at the websites of the U.S.

Bureau of Land Management and the USGS, and the aerial/satellite photographs are available at the website of Nationwide Environmental Title Research (NETR) Online and through the Google Earth software.

FIELD SURVEY
On January 19, 2024, CRM TECH archaeologists Michael D. Richards and Malika Mobley carried out the field survey of the project area with the assistance of ACBCI Cultural Resources Analyst Claritsa Duarte from the Tribal Historic Preservation Office. The survey was conducted at an intensive level by walking a series of parallel north -south transects at 15 -meter (approximately 50 - foot) intervals. In this way, the entire project area was systematically and carefully examined for any evidence of human activities dating to the prehistoric or historic period (i.e., 50 years or older).

Ground visibility was fair (-50 percent) in areas where there were low-lying grasses but excellent (-90 percent) where there was little to no vegetation.
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RESULTS AND FINDINGS

RECORDS SEARCH
According to EIC records, the project area had been surveyed for cultural resources once prior to this study (RI -08506 in Figure 5; Sander 2010). No cultural resources have been recorded on or adjacent to the property, however. Within the one -mile scope of the records search, EIC records identified a total of 30 previous studies completed on various tracts of land and linear features between 1979 and 2016 (Figure 5).

As a result of these and other similar studies in the vicinity, one historic -period site and one prehistoric -period site were previously recorded within the scope of the records search but outside the current project area. The historic -period site (33-005513) was recorded as the Peterson Ranch, a single wood frame house ca. 1930s (Wagner 1982). The prehistoric -period site (33-000628/CA- RIV-628T) consists of a trail segment and several stone cairns (Banks 1979; Parr and Arkush 1988; Bissell 2000). These previously recorded cultural resources were found more than a quarter mile from the project location. As such, none of them requires further consideration during this study.

NATIVE AMERICAN PARTICIPATION
In response to CRM TECH's inquiry, the NAHC reported in a letter dated January 18, 2024, that the Sacred Lands File identified no Native American cultural resources in the project vicinity but recommended contacting local Native American groups for further information. For that purpose, the NAHC provided a list of potential contacts in the region. The NAHC's reply is attached to this report in Appendix 2 for reference by the City of Rancho Mirage in future government -to - government consultations, if necessary.

As mentioned above, the ACBCI, which is the nearest tribe to the project location, participated in the archaeological field survey for this study on January 19, 2024. In a letter dated December 26, 2023, Xitlaly Madrigal, Cultural Resources Analyst with the ACBCI Tribal Historic Preservation Office, identified the project location as a part of the tribe's Traditional Use Area. Therefore, the ACBCI requested copies of all cultural resources documentation generated for this project for review by the Tribal Historic Preservation Office as well as the presence of an ACBCI Cultural Resource Monitor (see App. 2).

HISTORICAL BACKGROUND RESEARCH
Historical sources consulted for this study indicate that the entire project area was unsettled and undeveloped until the mid -20th century (Figures 6-9). Between the 1850s and the 1930s, no human - made features of any kind were noted within or adjacent to the project area despite its location near the Southern Pacific Railroad (built in the 1870s), U.S. Highway 60/70/99 (built prior to the 1920s), and two other major transportation arteries located approximately two miles to the north (Figures 6- 8). By the 1940s, Rio del Sol Road, the forerunner of present-day Bob Hope Drive, had been completed near the project vicinity along with several date gardens and ranches and a structure was present in the southern part of the project area (Figure 9). 16 Lot Subdivision — Rancho Mirage
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Scope of
records
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Figure 5. Previous cultural resources studies in the vicinity of the project area, listed by EIC file number. Locations of known historical/archaeological resources are not shown as a protective measure. 16 Lot Subdivision — Rancho Mirage
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Project
area
0 2000 4000 feet
Figure 6. The project area and vicinity in 1855-1856.
(Source: GLO 1856a,b)
Figure 7. The project area and vicinity in 1901. (Source:

USGS 1904)
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Figure 8. The project area and vicinity in 1941. (Source:

USGS 1941a, b)
Figure 9. The project area and vicinity in 1956-1958.
(Source: USGS 1958)

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By 1957, roads and housing appeared around and within the project area (Figure 9; NETR Online 1972). To the south of the project location, Gerald Ford Drive was first laid out between 1979 and 1984 and subsequently became a paved road by 1996, which ushered in a period of rapid urban growth in the surrounding area (NETR Online 1977-1996). The residential neighborhoods to the north and the south of the project location and the commercial properties to the west were all developed since then (NETR Online 1996-2020; Google Earth 1996-2023). The project area was not involved in any of these nearby developments. The structures in the southern part of the project area appears to have been removed after 2005 but before 2009 (NETR Online 1996-2020; Google Earth 1996-2023). The rest of the study area, however, has remained undeveloped and largely unused to the present time (NETR Online 1996-2020; Google Earth 1996-2023).

FIELD SURVEY
The field survey of the project area produced completely negative results for any potential "historical resources," and no buildings, structures, objects, sites, features, or artifacts more than 50 years of age were encountered within the project boundaries. The entirety of the project area has been disturbed in the past, with all native vegetation being removed. Previous modern development and demolition have impacted the ground surface. Modern debris is comprised of milled lumber fragments, PVC pipe, chain fencing, broken glass bottle fragments, a few steel cans, and paper and building material refuse. No evidence of the structures previously located in the southern portion of the project area were observed. There are residential developments, a paved road, fencing along the Whitewater drainage, and utility poles, adjacent to the project area, but all of these items are modern in origin and, therefore, none of them are of any historical/archaeological interest.

DISCUSSION
The purpose of this study is to identify any cultural resources within the project area and to assist the City of Rancho Mirage in determining whether such resources meet the official definition of "historical resources," as provided in the California Public Resources Code, in particular CEQA.

According to PRC §5020.1(j), "`historical resource' includes, but is not limited to, any object, building, site, area, place, record, or manuscript which is historically or archaeologically significant, or is significant in the architectural, engineering, scientific, economic, agricultural, educational, social, political, military, or cultural annals of California." More specifically, CEQA guidelines state that the term "historical resources" applies to any such resources listed in or determined to be eligible for listing in the California Register of Historical Resources, included in a local register of historical resources, or determined to be historically significant by the lead agency (Title 14 CCR §15064.5(a)(1)-(3)). Regarding the proper criteria for the evaluation of historical significance, CEQA guidelines mandate that "generally a resource shall be considered by the lead agency to be `historically significant' if the resource meets the criteria for listing on the California Register of Historical Resources" (Title 14 CCR §15064.5(a)(3)). A resource may be listed in the California Register if it meets any of the following criteria:
(1) Is associated with events that have made a significant contribution to the broad patterns of California's history and cultural heritage.
(2) Is associated with the lives of persons important in our past. 16 Lot Subdivision — Rancho Mirage
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(3) Embodies the distinctive characteristics of a type, period, region, or method of construction, or represents the work of an important creative individual, or possesses high artistic values. (4) Has yielded, or may be likely to yield, information important in prehistory or history. (PRC §5024.1(c))
In summary of the research results presented above, no potential "historical resources" were previously recorded within or adjacent to the project area, and none was found during the present survey. In addition, Native American input during this study identified no properties of traditional cultural value in the project vicinity. Based on these findings, and considering the criteria listed above, the present report concludes that no historical resources exist within or adjacent to the project area. Therefore, CRM TECH recommends to the City of Rancho Mirage a finding of No Impact regarding "historical resources."

CONCLUSIONS AND RECOMMENDATIONS
CEQA establishes that a project that may cause a substantial adverse change in the significance of a "historical resource" is a project that may have a significant effect on the environment (PRC §21084.1). "Substantial adverse change," according to PRC §5020.1(q), "means demolition, destruction, relocation, or alteration such that the significance of a historical resource would be impaired." As stated above, no "historical resources," as defined by CEQA, were encountered throughout the course of this study. Therefore, CRM TECH presents the following recommendations to the City of Rancho Mirage:
• The proposed project will not cause a substantial adverse change to any known "historical resources."
• No further cultural resources investigation is necessary for the project unless development plans undergo such changes as to include areas not covered by this study. • If buried cultural materials are discovered during any earth -moving operations associated with the project, all work in that area should be halted or diverted until a qualified archaeologist can evaluate the nature and significance of the finds.
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REFERENCES
Anderson, M. Kat
2005 Tending the Wild: Native American Knowledge and the Management of California's Natural Resources. University of California Press, Berkeley.

Banks, Thomas
1979 Site Record for Site 33-000628 (CA-RIV-628T). On File, Eastern Information Center, University of California, Riverside.

Bean, Lowell John
1978 Cahuilla. In Robert F. Heizer (ed.): Handbook of North American Indians, Vol. 8:

California; pp. 575-587. Smithsonian Institution, Washington, D.C.

Bean, Lowell John, and Katherine Siva Saubel
1972 Temalpakh: Cahuilla Indian Knowledge and Usage of Plants. Malki Museum Press, Banning, California.

Bissell, Ron M.
2000 Site Record (Update) for Site 33-000628 (CA-RIV-628T). On File, Eastern Information Center, University of California, Riverside.

CSRI (Cultural Systems Research, Inc.)
2002 The Native Americans of Joshua Tree National Park: An Ethnographic Overview and Assessment Study. Http:// www.cr.nps.gov/history/online_books/j otr/history6.htm.

GLO (General Land Office, U.S. Department of the Interior) 1856a Plat map: Township No. IV South Range No. V East, San Bernardino Meridian; surveyed in 1855-1856.
1856b Plat map: Township No. V South Range No. V East, San Bernardino Meridian; surveyed in 1855-1856.

Google Earth
1996-2023 Aerial/satellite photographs of the project vicinity; taken in 1996, 2002, 2004-2006, 2009, 2011-2013, 2015-2019, and 2021-2023. Available through the Google Earth software.

Gunther, Jane Davies
1984 Riverside County, California, Place Names: Their Origins and Their Stories. J.D.

Gunther, Riverside.

Johnston, Francis J.
1987 The Bradshaw Trail; revised edition. Historical Commission Press, Riverside.

Kroeber, Alfred L.
1925 Handbook of the Indians of California. Bureau of American Ethnology Bulletin 78.

Government Printing Office, Washington, D.C.

Laflin, Patricia
1998 Coachella Valley California: A Pictorial History. The Donning Company, Virginia Beach, Virginia.

Love, Bruce, and Bai "Tom" Tang
1996 Cultural Resources Report: Rancho Mirage General Plan, City of Rancho Mirage, Riverside County, California. On File, Eastern Information Center, University of California, Riverside.
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NETR (Nationwide Environmental Title Research) Online
1959-2020 Aerial/satellite photographs of the project vicinity; taken in 1959, 1972, 1977, 1979, 1984, 1996, 2002, 2005, 2009, 2010, 2012, 2014, 2016, 2018, and 2020. http://www.historicaerials.com .

Parr, R.E and B.S. Arkush
1988 Site Record Update for Site 33-000628 (CA-RIV-628T). On File, Eastern Information Center, University of California, Riverside.

Robinson, W.W.
1948 Land in California. University of California Press, Berkeley.

Ross, Delmer G.
1992 Gold Road to La Paz: An Interpretive Guide to the Bradshaw Trail. Tales of the Mojave Road Publishing Company, Essex, California.

Sander, Jay K.
2010 A Phase I Cultural Resources Inventory for APN 689-090-003, 689-130-004, 689-130- 005,689-130-013, 689-130-014, 689-130-017, 689-130-018, and 689-140-022 Comprising Approximately 20 Acres Rancho Mirage, Riverside County, California. On file at Eastern Information Center.

Schaefer, Jerry
1994 The Challenge of Archaeological Research in the Colorado Desert: Recent Approaches and Discoveries. Journal of California and Great Basin Anthropology 16(1):60-80.

Shields Date Gardens
1957 Coachella Valley Desert Trails and the Romance and Sex Life of the Date. Shields Date Gardens, Indio.

Strong, William Duncan
1929 Aboriginal Society in Southern California. University of California Publications in American Archaeology and Ethnology, Vol. 26.

USGS (United States Geological Survey, U.S. Depailment of the Interior) 1904 Map: Indio, Calif. (30', 1:125,000); surveyed in 1901. 1941a Map: Edom, Calif. (15', 1:62,500); aerial photographs taken in 1941. 1941b Map: Toro Peak, Calif. (15', 1:62,500); aerial photographs taken in 1941. 1958 Map: Cathedral City, Calif. (7.5', 1:24,000); aerial photographs in 1956. 1979 Map: Santa Ana, Calif. (1:250,000); 1959 edition revised. 1981 Map: Cathedral City, Calif. (7.5', 1:24,000); 1958 edition photorevised in 1978. 1988 Map: Rancho Mirage, Calif. (7.5', 1:24,000); 1957 edition photorevised in 1984.

Wagner, Jim
1982 Site Record for Site 33-005513. On File, Eastern Information Center, University of California, Riverside.
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Education
2016-
2010
2005
2019
2014
APPENDIX 1:

PERSONNEL QUALIFICATIONS
FRANK J. RASLICH, M.A.

Project Archaeologist/Report Writer
Ph.D. candidate, Michigan State University, East Lansing.

M.A., Anthropology, Michigan State University, East Lansing.

B.A., Anthropology, University of Michigan, Flint.

Grant and Research Proposal Writing for Archaeologists; Society for American Archaeology online seminar.

Bruker Industries Tracer S1800 pXRF Training; presented by Dr. Bruce Kaiser, Bruker Scientific.

Professional Experience
2022-
2022
2014-2022
2008-2021
2019
2016-2018
2017-2018
2009-2017
2008-2014
2010-2013
2009-2011
Publications
Project Archaeologist/Report Writer, CRM TECH, Colton, California.

Archaeological Monitor, Agua Caliente Band of Cahuilla Indians, Palm Springs, California.

Board of Directors, Ziibiwing Center of Anishinabe Culture and Lifeways, Saginaw Chippewa Indian Tribe of Michigan.

Archaeological Consultant, Saginaw Chippewa Indian Tribe of Michigan.

Archaeologist, Sault Tribe of Chippewa Indians and Little Traverse Bay Band of Odawa Indians.

Adjunct Lecturer, Michigan State University, East Lansing.

Adjunct Lecturer, University of Michigan, Flint.

Teaching Assistant, Michigan State University, East Lansing.

Research Assistant, Intellectual Property Issues in Cultural Heritage, Simon Fraser University, British Columbia, Canada.

Research Assistant, Michigan State University, East Lansing.

Archaeologist/Crew Chief, Saginaw Chippewa Indian Tribe of Michigan. 2017 Preliminary Results of a Handheld X -Ray Fluorescence (pXRF) Analysis on a Marble Head Sarcophagus Sculpture from the Collection of the Kresge Art Center, Michigan State University. Submitted to Jon M. Frey, Department of Art, Art History, and Design, Michigan State University, East Lansing.
2013 Geochemical Analysis of the Dickenson Group of the Upper Peninsula, Michigan: A study of an Accreted Terrane of the Superior Province. Geological Society of America Abstracts with Programs 45:4(53)
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MICHAEL HOGAN, PH.D., RPA*
Principal Investigator/Archaeologist
Education
1991 Ph.D., Anthropology, University of California, Riverside. 1981 B.S., Anthropology, University of California, Riverside; with honors. 2021 "An Introduction to Geoarchaeology: How Understanding Basic Soils, Sediments, and Landforms can make you a Better Archaeologist." SAA Online Seminar. 2002 "Section 106 —National Historic Preservation Act: Federal Law at the Local Level," UCLA Extension Course #888.
2002 "Recognizing Historic Artifacts," workshop presented by Richard Norwood, Historical Archaeologist.
2002 "Wending Your Way through the Regulatory Maze," symposium presented by the Association of Environmental Professionals.
1992 "Southern California Ceramics Workshop," presented by Jerry Schaefer. 1992 "Historic Artifact Workshop," presented by Anne Duffield -Stoll.

Registrations
*Registered Professional Archaeologist 41781498
Professional Experience
2002- Principal Investigator, CRM TECH, Riverside/Colton, California. 1999-2002 Field Director/Project Archaeologist/Project Paleontologist, CRM TECH. 1996-1998 Project Director and Ethnographer, Statistical Research, Inc., Redlands. 1992-1998 Assistant Research Anthropologist, University of California, Riverside 1992-1995 Project Director, Archaeological Research Unit, U.C. Riverside. 1991-1992 Crew Chief, Archaeological Research Unit, U.C. Riverside. 1984-1998 Project Director, Field Director, Crew Chief, and Archaeological Technician for various southern California cultural resources management firms.

Research Interests
Cultural Resource Management, Southern Californian Archaeology, Settlement and Exchange Patterns, Specialization and Stratification, Culture Change, Native American Culture, Cultural Diversity.

Cultural Resources Management Reports
Principal investigator for, author or co-author of, and contributor to numerous cultural resources management study reports since 1986.

Memberships
Society for American Archaeology; Society for California Archaeology; Pacific Coast Archaeological Society; Coachella Valley Archaeological Society. 16 Lot Subdivision — Rancho Mirage
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MICHAEL D. RICHARDS, M.A., RPA
Project Archaeologist
Education
2002 M.A., Anthropology, California State University, Northridge (CSUN). 1986 B.A., Anthropology: University of California, Los Angeles (UCLA). 1982 A.A., Los Angeles Valley College, Los Angeles, California. 2015 Section 106 workshop.
2000 CSUN "Olmec" field excavation and lab analysis; La Venta, Mexico. 1999 Rock art recording, UCLA Extension; Little Lake, California. 1998 Rock art symposium, UCLA Extension.

Professional Experience
2018- Project Archaeologist/Paleontologist, CRM TECH, Colton, Calif. 2016-2018 Co -Principal Investigator/Archaeologist, LSA Associates Inc. 2012-2016 Co -Principal Investigator/Archaeologist, ICF International (Jones & Stokes). 2010-2012 Co -Principal Investigator/Archaeologist, various CRM firms (on call). 2007-2010 Principal Investigator/Field Director/Crew Chief, ASM Affiliates, Inc. 2004-2007 Project Manager/Co-Principal Investigator, ArchaeoPaleo Resource Management, Inc. 2003-2004 Staff Archaeologist/Crew Chief, SRI, Inc.
2000-2003 Project Archaeologist/Field Director, Ancient Enterprises (Clewlow, Jr.). 1999-2000 Staff Archaeologist/Lab Crew Chief, CSC/Edwards Air Force Base.

Research Interests
Pottery and rock art analysis; prehistory the American southwest; Mesoamerica; Japan.

Cultural Resources Management Reports
Author and co-author of, contributor to, and principal investigator for numerous cultural resources management study reports since 1999.

Memberships
Society for American Archaeology; Society for California Archaeology; Archaeological Institute of America; Conejo Open Space Trails Advisory Committee; Conejo Valley Historical Society. 16 Lot Subdivision — Rancho Mirage
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NINA GALLARDO, B.A.

Project Archaeologist/Native American Liaison
Education
2004 B.A., Anthropology/Law and Society, University of California, Riverside.

Professional Experience
2004- Project Archaeologist, CRM TECH, Riverside/Colton, California.

Cultural Resources Management Reports
Co-author of and contributor to numerous cultural resources management reports since 2004. 16 Lot Subdivision — Rancho Mirage
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APPENDIX 2

NATIVE AMERICAN SCOPING RESPONSES
16 Lot Subdivision — Rancho Mirage
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SACRED LANDS FILE & NATIVE AMERICAN CONTACTS LIST REQUEST

NATIVE AMERICAN HERITAGE COMMISSION
1550 Harbor Boulevard, Suite 100
West Sacramento, CA 95691
(916)373-3710
(916)373-5471 (Fax)
[email protected]
Project: Proposed 16 -Lot Subdivision Project; APNs 689-090-003, 689-130-004, -005, -013, -014, - 017, and 689-140-022 (CRM TECH No. 4085)
County: Riverside
USGS Quadrangle Name: Cathedral City and Rancho Mirage, Calif.

Township 5 South Range 5 East SB BM; Section(s) 2
Company/Firm/Agency: CRM TECH
Contact Person: Nina Gallardo
Street Address: 1016 E. Cooley Drive, Suite AB
City: Colton, CA Zip: 92324
Phone: (909) 824-6400 Fax: (909) 824-6405
Email: [email protected]
Project Description: The primary component of the project is to subdivide the property into a 16 -lot residential development on approximately 20 acres, is located on both the east and west side of Peterson Road, north of Mirage Cove Drive and south of the Whitewater River, in the City of Rancho Mirage, Riverside County, California
December 21, 2023
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STATE OF CALIFORNIA Gavin Newsom Governor

NATIVE AMERICAN HERITAGE COMMISSION
January 18, 2024
Nina Gallardo

CRM TECH
Via Email to: ngal'lardofl?crmtech_us
Re: Proposed 16 -Lot Subdivision Project, Riverside County Dear Ms. Gallardo:

A record search of the Native American Heritage Commission (NAHCI Sacred Lands File (SLF wcl5 completed for the information you have submitted for the above referenced project. The results were negative. However, the absence of specific site information in the SLF does not indicate the absence of cultural resources in any project area. Other sources of cultural resources should also be contacted for information regarding known and recorded sites.

Attached is a list of Native American tribes who may also have knowledge of cultural resources in the project area_ This list should provide a starting place in locating areas of potential adverse impact within the proposed project area_ I suggest you contact all of those indicated; if they cannot supply information, they might recommend others with specific knowledge. By contacting' all those listed, your organization will be better able to respond to claims of failure to consult with the appropriate tribe. It a response has not been received within two weeks of notification, the Commission requests that you follow-up with a telephone call or email to ensure that the project information has been received.

If you receive notification of change of addresses and phone numbers from tribes, please notify me. With your assistance, we can assure that our lists contain current information.

If you have any questions or need additional information, please contact me at my email address: Andrew.Greeniunohc.ca.aov.

Sincerely,
aYtditeGGr
Andrew Green
Cultural Resources Anatyst
Attachment

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Cultural Resource Assessment
Native American Heritage Commission
Native American Contact List
Riverside County
1/18/2024
Tribe Name Fed (F) Contact Person Contact Address Phone # Fax # Email Address Cultural Non -Fed Affiliation
(N)
Counties
Agua Caliente Band of
F
Lacy Padilla, THPO
5401 Dinah Shore Drive
(760) 333-
(760) 699-
[email protected]
Cahuilla
Imperial,Riverside,San
Cahuilla Indians
Operations Manager
Palm Springs, CA, 92264
5222
6919
Bernardino,San Diego
Augustine Band of Cahuilla
F
Tribal Operations,
84-001 Avenue 54
(760) 398-
Cahuilla
Imperial,Riverside,San
Indians
Coachella, CA, 92236
4722
Bernardino,San Diego
Cabazon Band of Mission
F
Doug Welmas,
84-245 Indio Springs
(760) 342-
(760) 347-
[email protected]
Cahuilla
Imperial,Riverside,San
Indians
Chairperson
Parkway
2593
7880
Bernardino,San Diego
Indio, CA, 92203
Cahuilla Band of Indians
F
BobbyRay Esaprza,
52701 CA Highway 371
(951) 763-
[email protected]
Cahuilla
Imperial,Riverside,San
Cultural Director
Anza, CA, 92539
5549
Bernardino,San Diego
Cahuilla Band of Indians
F
Anthony Madrigal, Tribal
52701 CA Highway 371
(951) 763-
[email protected]
Cahuilla
Imperial,Riverside,San
Historic Preservation
Anza, CA, 92539
5549
Bernardino,San Diego
Officer
Cahuilla Band of Indians
F
Daniel Salgado,
52701 CA Highway 371
(951) 972-
(951) 763-
[email protected]
Cahuilla
Imperial,Riverside,San
Chairperson
Anza, CA, 92539
2568
2808
Bernardino,San Diego
Los Coyotes Band of Cahuilla
and Cupeno Indians
F
Ray Chapparosa,
Chairperson
P.O. Box 189
Warner Springs, CA,
92086-0189
(760) 782-
0711
(760) 782-
0712
Cahuilla
Imperial,Riverside,San
Bernardino,San Diego
Morongo Band of Mission
F
Robert Martin,
12700 Pumarra Road
(951) 755-
(951) 755-
[email protected]
Cahuilla
Imperial,Los
Indians
Chairperson
Banning, CA, 92220
5110
5177
Serrano
Angeles,Riverside,San
Bernardino,San Diego
Morongo Band of Mission
F
Ann Brierty, THPO
12700 Pumarra Road
(951) 755-
(951) 572-
[email protected]
Cahuilla
Imperial,Los
Indians
Banning, CA, 92220
5259
6004
Serrano
Angeles,Riverside,San
Bernardino,San Diego
Quechan Tribe of the Fort
F
Manfred Scott, Acting
P.O. Box 1899
(928) 210-
[email protected]
Quechan
Imperial,Kern,Los
Yuma Reservation
Chairman - Kw'ts'an
Yuma, AZ, 85366
8739
Angeles,Riverside,San
Cultural Committee
Bernardino,San Diego
Quechan Tribe of the Fort
F
Jordan Joaquin, President,
P.O.Box 1899
(760) 919-
[email protected]
Quechan
Imperial,Kern,Los
Yuma Reservation
Quechan Tribal Council
Yuma, AZ, 85366
3600
Angeles,Riverside,San
Bernardino,San Diego
Quechan Tribe of the Fort
F
Jill McCormick, Historic
P.O. Box 1899
(928) 261-
[email protected]
Quechan
Imperial,Kern,Los
Yuma Reservation
Preservation Officer
Yuma, AZ, 85366
0254
Angeles,Riverside,San
Bernardino,San Diego
Ramona Band of Cahuilla
F
John Gomez,
P. O. Box 391670
(951) 763-
(951) 763-
[email protected]
Cahuilla
Imperial,Riverside,San
Environmental Coordinator
Anza, CA, 92539
4105
4325
Bernardino,San Diego

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1 rah
Ramona Band of Cahuilla
F
Joseph Hamilton,
Chairperson
P.O. Box 391670
Anza, CA, 92539
(951) 763-
4105
(951) 763-
4325
[email protected]
Cahuilla
Imperial,Riverside,San
Bernardino,San Diego
Santa Rosa Band of Cahuilla
Indians
F
Lovina Redner, Tribal
Chair
P.O. Box 391820
Anza, CA, 92539
(951) 659-
2700
(951) 659-
2228
[email protected]
Cahuilla
Imperial,Los
Angeles,Orange,Riverside,San
Bernardino,San Diego
Soboba Band of Luiseno
Indians
F
Joseph Ontiveros, Tribal
Historic Preservation
Officer
P.O. Box 487
San Jacinto, CA, 92581
(951) 663-
5279
(951) 654-
4198
[email protected]
Cahuilla
Luiseno
Imperial,Los
Angeles,Orange,Riverside,San
Bernardino,San Diego
Soboba Band of Luiseno
Indians
F
Jessica Valdez, Cultural
Resource Specialist
P.O. Box 487
San Jacinto, CA, 92581
(951) 663-
6261
(951) 654-
4198
[email protected]
Cahuilla
Luiseno
Imperial,Los
Angeles,Orange,Riverside,San
Bernardino,San Diego
Torres -Martinez Desert
Cahuilla Indians
F
Mary Belardo, Cultural
Committee Vice Chair
P.O. Box 1160
Thermal, CA, 92274
(760) 397-
0300
[email protected]
Cahuilla
Imperial,Riverside,San
Bernardino,San Diego
Torres -Martinez Desert
Cahuilla Indians
F
Gary Resvaloso, TM MLD
P.O. Box 1160
Thermal, CA, 92274
(760) 777-
0365
[email protected]
Cahuilla
Imperial,Riverside,San
Bernardino,San Diego
Torres -Martinez Desert
Cahuilla Indians
F
Abraham Becerra, Cultural
Coordinator
P.O. Box 1160
Thermal, CA, 92274
(760) 397-
0300
[email protected]
Cahuilla
Imperial,Riverside,San
Bernardino,San Diego
Torres -Martinez Desert
Cahuilla Indians
F
Thomas Tortez,
Chairperson
P.O. Box 1160
Thermal, CA, 92274
(760) 397-
0300
(760) 397-
8146
[email protected]
Cahuilla
Imperial,Riverside,San
Bernardino,San Diego
Torres -Martinez Desert
Cahuilla Indians
F
Alesia Reed, Cultural
Committee Chairwoman
P.O. Box 1160
Thermal, CA, 92274
(760) 397-
0300
[email protected]
Cahuilla
Imperial,Riverside,San
Bernardino,San Diego
This list is current only as of the date of this document. Distribution of this list does not relieve any person of statutory responsibility as defined in Section 7050.5 of the Health and Safety Code, Section 5097.94 of the Public Resource Section 5097.98 of the Public Resources Code.

This list is only applicable for contacting local Native Americans with regard to cultural resources assessment for the proposed Proposed 16 -Lot Subdivision Project, Riverside County.

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1204

FROM: [email protected]
SENT: THURSDAY, DECEMBER 21, 2023 10:22 AM
To: 'THPO CONSULTING'
CC: MADRIGAL, XITLALY (TRBL)
SUBJECT: CULTURAL STUDY AND PARTICIPATION IN FIELD SURVEY FOR THE PROPOSED 16 -LOT SUBDIVISION PROJECT, IN THE CITY OF RANCHO MIRAGE (CRM TECH No. 4085) ATTAcui IENTs:4085 NAHC REQUEST.DOCx; 4085 PA MAP.JPG
HELLO,

I'M WRITING TO INFORM YOU THAT CRM TECH WILL BE CONDUCTING A CULTURAL RESOURCES STUDY FOR THE PROPOSED 16 -LOT SUBDIVISION PROJECT (APNs 689-090-003, 689-130-004, -005, -013, -014, -017, AND 689-140-022), IN THE CITY OF RANCHO MIRAGE, RIVERSIDE COUNTY, CALIFORNIA (CRM TECH No. 4085).

SPECIFICALLY, I AM CONTACTING YOU TO SEE IF THE TRIBE WOULD LIKE TO PARTICIPATE IN THE FIELD SURVEY OF THE PROPERTY. WE WILL CONTACT YOU AGAIN WHEN WE BEGIN TO SET UP A SPECIFIC TIME AND DATE FOR THE FIELDWORK ONCE WE HAVE COMPLETED THE RECORD SEARCH AT THE EIC.

WE ARE ALSO ASKING FOR ANY INFORMATION REGARDING ANY TRIBAL CULTURAL RESOURCES WITHIN OR NEAR THE PROPOSED PROJECT LOCATION. I'M ALSO ATTACHING THE PROPOSED PROJECT AREA MAP, AND PROJECT INFORMATION. WE WOULD ALSO APPRECIATE ANY INFORMATION THAT THE TRIBE MAY PROVIDE THAT CRM TECH CAN INCLUDE IN OUR REPORT. PLEASE FEEL FREE TO EMAIL BACK WITH ANY QUESTIONS,

COMMENTS AND/ OR INFORMATION REGARDING THE PROPOSED PROJECT, AND POSSIBLE AVAILABILITY FOR THE FIELD SURVEY.

THANK YOU FOR YOUR TIME AND INPUT ON THIS PROJECT.

NINA GALLARDO
(909) 824-6400 (PHONE)
(909) 824-6405 (FAx)

CRM TECH
1016 E. COOLEY DRIVE, STE. A/B
COLTON, CA 92324
FROM: MADRIGAL, XITLALY (TRBL)
SENT: WEDNESDAY, JANUARY 17, 2024 11:30 AM
To: '[email protected]'
CC: PADILLA, LACY (TRBL); DUARTE, CLARITSA (TRBL)
SUBJECT: RE: PROFESSIONAL OFFICE AND ART GALLERY
SOUNDS GOOD, CLARITSA WILL MEET MICHAEL OUT AT 7 AM AND IS AVAILABLE FOR BOTH SURVEYS.

THANK YOU,

XITLALY MADRIGAL

CULTURAL RESOURCES ANALYST
[email protected]
C: (760) 423-3485 I D: (760) 883-6829
5401 DINAH SHORE DRIVE, PALM SPRINGS, CA 92264
1205

Page 25 of 27 ends

AGUA C LIEr1TE BAND OF CAHLUILL.A INDIANN'c
I I'irEJ.LL E'�.IE1t1F 1r= HIV= =f t-V'Vwi ll Vll
December 26, 2023
[VIA EMAIL TO:ngallardo@,crintech.us]

CHNI TECH
Ms. Nina Gallardo
1016 E. Cooley Drive, Suite AlB
Colton, CA92324
R 16 -Lot. Subdivision in Rancho 1Vlirage
Dear Ms. Nina Gall ardo,
s
03-008-2023-009
The Agua Caliente Band of Cahuilla Indians (ACB CI) appreciates your efforts to include the Tribal Historic Preservation Office (TI-EPO) in the 16 -Lot Subdivision project. The project area is not located within the boundaries of the ACBCI Reservation. However, it is within the Tribe's Traditional Use Area. For this reason, the ACB CI THPO requests the following:
*A cultural resources inventory of the project area by a qualified archaeologist prior to any development activities in this area.
*A copy of the records search with associated survey reports and site records from the inform ati on center.
*Copies of any cultural resource documentation (report and site records) generated in connection with this project.
*The presence of an approved Agua Caliente Native American Cultural. Resource Monitor(s) during any ground disturbing activities (including archaeological testing and surveys). Should buried cultural deposits be encountered, the Monitor may request that destructive construction halt and the Monitor shall notify a Qualified Archaeologist (Secretary of the Interior's Standards and Guidelines) to investigate and, if necessary, prepare a mitigation plan for submission to the State Historic Preservation Officer and the Agua Caliente Tribal Historic Preservation Office.

Again, the Agua Caliente appreciates your interest in our cultural heritage. If you have questions or re quire additional information, please call me at (760) 423-3485. You may also email me at ACB CI- _'[email protected].

Cordially,
1206

Page 26 of 27 ends

AGUA CALIENTE BAND OF CAHUILLA INDIANS
SRtEAL Misr:19IG PRESFRVokT€OW
Xitlaly Madn gal
Cultural Resources Analyst
Tribal Historic Preservation Office

AQUA CALIENTE BAND

OF CAHUILLA INDIANS
•
540 tliNdhll SlIfi tI IIV4, Pe4.M SFIiINos, GA 9,2104
71A r•t + wi oy .y+O MYII{� ! P ofo,iovlFlrh Had WW W,h+a cl h r l -1L141 t hlsN 1207

Page 27 of 27 ends

APPENDIX D

PRELIMINARY HYDROLOGY STUDY
for
TENTATIVE TRACT MAP 38971

RANCHO MIRAGE, CALIFORNIA
Prepared for:

Horti Caesaris LLC
9401 Wilshire Blvd., 12th Floor
Beverly Hills, CA 90212-2928
Prepared by:

FOMO TOR

ENGINEERING
225 S. Civic Drive, Suite 1-5
Palm Springs, California 92262
Phone (760)323-1842
Fax (760)323-1742
July 9, 2024
1208

Table of Contents
I. Report
II. Reference Material
a. Vicinity Map
b. Flood Insurance Rate Map ( U.S. Department of Homeland Security Federal Emergency Management Act Map Service Center)
c. Hydrologic Soils Group Maps (From US Department of Agriculture Soil Conservation Service)
d. Point Precipitation Frequency (National Oceanic and Atmospheric Administration's Precipitation Frequency Data Server)
e. City of Rancho Mirage Retention Basin Standard Detail 310. f. Impervious Cover for Developed Areas — Plate D-5.6 (RCFC&WCD Hydrology Manual).
g. Runoff Index— Plate D-5.5-Pg 1 (RCFC&WCD Hydrology Manual). h. Pervious Area Loss Rate — Plate E-6.2 (RCFC&WCD Hydrology Manual).
i. SUH Shortcut Method Basin and Runoff Calculation Spreadsheet VI. Exhibit
i. Preliminary Hydrology Exhibit
1209

FOMOTOR ENGINEERING Preliminary Hydrology Study
Tentative Tract Map 38971

PRELIMINARY HYDROLOGY STUDY
FOR TENTATIVE TRACT MAP 38971

PROJECT SITE LOCATION
The 20.05 -acre 16 lot proposed Tentative Tract Map site is located on Peterson Road, west of Mirage Cove Drive, in the City of Rancho Mirage, County of Riverside, California. The proposed development site lies in Section 2, T5S, R5E, and SBBM, with APNs: 689-090-003, 689-130-004, -005, -013, -014, -017, -018 and 689-140-022.

PROJECT SITE DESCRIPTION
The project site is presently vacant. Existing elevations vary from 264 down to 257 with a slight slope. The site is entirely composed of Hydrologic Soil Type "A". A Tentative Tract Map is proposed on this site. The project site area is in shaded Zone X, which is described as: "2% Annual Chance Flood Hazard, Areas of 1% annual chance flood with average depth less than one foot or with drainage areas of less than one square mile". (See Riverside County Flood Insurance Rate Map numbers 06065C1589G and 06065C1595G, Effective August 28, 2008, in Reference Materials).

PURPOSE
Each proposed lot within the project site was separately analyzed for proposed condition basin capacity using Synthetic Unit Hydrograph Shortcut Method for the 1, 3, 6, and 24 -hour duration 100 -year storm event to determine the worst -case contributing runoff volume. This computed runoff volume was used to size a proposed retention basin for each lot as per City of Rancho Mirage Standard Detail 310 for Retention Basins. The runoff from each proposed onsite area would be directed via swale system to the proposed retention basin. Adjacent half street frontage was added to the runoff area of each lot.

METHODOLOGY
The materials included with this study are presented to satisfy the criteria set forth in the Riverside County Flood Control & Water Conservation District (RCFC & WCD) Hydrology Manual. The onsite/offsite post - developed condition design runoff volume was determined using the worst of the 1, 3, 6, and 24 -hour duration storm for the 100 -year event. Peak discharges of the 100 -year storm event will be determined with the Rational Formula. Synthetic Unit Hydrograph (SUH) calculations were performed in accordance with RCFC & WCD criteria. The Hydrologic Soil Group area was determined with the Natural Resources Conservation Service's National Cooperative Soil Survey (See Reference Material). Point precipitation frequency data was obtained with the National Oceanic and Atmospheric Administration's (NOAA) Precipitation Frequency Data Server from Atlas 14 (See Reference Material.). The NOAA point precipitation data of the 100 -year event will be plotted on a log -log plot to obtain the slope of intensity duration curve which will be used in the Rational Method analysis. Any necessary storm drains will be modeled with the computer modeling software, Hydraflow Storm Sewers Extensions for AutoCAD Civi13D 2024, by Autodesk, Inc. Any necessary storm drain inlets will be sized as per AutoCAD Hydraflow Express Extension, Version 12.

Page 1210 ends

July 9, 2024

FOMOTOR ENGINEERING
Preliminary Hydrology Study
Tentative Tract Map 38971

RESULT OF SYNTHETIC UNIT HYDROGRAPH ANALYSIS
Summary of results of the Synthetic Unit Hydrograph (SUH) analysis are as follows:

Please refer to the attached Hydrology Plan, and SUH Calculation Spreadsheets in the Reference Materials Proposed Onsite and Offsite Area Runoff to Basins

BASIN ID

CONTRIBUTING

AREA (ACRES)
(STREET

OFFSITE

FRONTAGE

0.09AC)
STORM

FREQUENCY
(YEAR)

DURATION
(HOUR)
PEAK
RUNOFF

STORAGE

VOLUME VS

INFILTRATION
(CU -FT) -POST
DEV
BASIN

CAPACITY
(CU -FT)
BASIN
DEPTH
(FT)
PEAK
BASIN
WATER
DEPTH
(FT)
LOT 1

1.09(1.00+0.09)
100
1 7,307
8,996
4 3.25
LOT 2

1.16(1.07+0.09)
100
1 7,777
8,239
4 3.78
LOT 3

1.18(1.09+0.09)
100
1 7,911
8,239
4 3.84
LOT 4

1.18(1.09+0.09)
100
1 7,911
8,239
4 3.84
LOT 5

1.18(1.09+0.09)
100
1 7,911
8,239
4 3.84
LOT 6

1.25(1.16+0.09)
100
1 8,380
8,471
4 3.96
LOT 7

1.25(1.16+0.09)
100
1 8,380
8,471
4 3.96
LOT 8

1.07(0.98+0.09)
100
1 7,173
8,239
4 3.48
LOT 9

1.07(0.98+0.09)
100
1 7,173
8,239
4 3.48
LOT 10

1.23(1.14+0.09)
100
1 8,246
8,331
5 4.95
LOT 11

1.45(1.36+0.09)
100
1 9,721
9,830
5 4.94
LOT 12

1.64(1.55+0.09)
100
1 10,995
11,159
5 4.93
LOT 13

1.12(1.03+0.09)
100
1 7,508
8,239
4 3.65
LOT 14

1.12(1.03+0.09)
100
1 7,508
8,239
4 3.65
LOT 15

1.12(1.03+0.09)
100
1 7,508
8,239
4 3.65
LOT 16

1.11(1.02+0.09)
100
1 7,441
8,239
4 3.61

DISCUSSION
Basin infiltration was not used to size the retention basins. A percolation test will be performed in the future. The 1 -hour storm was determined to be the worst case of the 1, 3, 6, and 24 -hour duration 100 -year storm events for the Synthetic Unit Hydrograph analysis. In general, each lot will have an independent retention basin sized to contain the 100 -year 1 -hour runoff from each respective lot as well as the adjacent half -street frontage. Each basin will be four to five feet deep with 3 to 1 side slopes and receive runoff from swale flow (See SUH Shortcut Calculations and Preliminary Hydrology Plan in the Reference Materials).

The impermeable area used for calculations was based on a 1 -acre residential lot from Plate D-5.6 of the RCFC&WCD Hydrology Manual and the adjacent half -street frontage was added. The Runoff Index was selected from Plate D-5.5 (1 of 2) of the RCFC&WCD Hydrology Manual.

Page 21 ends

July 9, 2024

REFERENCE MATERIAL
1212

Google Maps Peterson Rd & Mirage Cove Dr
s Cafe
fast • 5S
Victoria's, Attic Antiques
Desert Specialty Grou
Mirage C° -e ra
t7
Lincoln Downs St
Tanforan
o
C5
Tropical Park St
a
o o`
✓ a cc
m c
?C u
E _
o z
To
Mirage Cove Dr Mirage Cove Dr
nsignments
-rage
a. •55
6 . Las Casuelas Nuevas
Springs
the area
Exterior Illu ns'
Outdacr Furn re
Outclecr furniture or
Via Florencto
9,Vista'Cove at
Rancho Mirage
Ridgeline Way.
iso Desert Cove Ave
iI5
Public Storage
Santa Rosa Villa
9 Jnnrpr,
Carla Ln • t ;or,gle
48 Rancho Mirage RV
•4
& Mobile Village
Morningside
Community Association
9 \The Club at Momingslde
Map data ©2024 Google 200 ft

National Flood Hazard Layer FIRMette
FEMA
Legend

SEE FIS REPORT FOR DETAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT

SPECIAL FLOOD

HAZARD AREAS
Without Base Flood Elevation (BFE)
Zone A, V. A99
With BFE or Depth Zone AE. Ao. AH. VE, AR
Regulatory Floodway

OTHER AREAS OF

FLOOD HAZARD

OTHER AREAS

GENERAL

STRUCTURES
OTHER

FEATURES

MAP PANELS
9 0.2% Annual Chance Flood Hazard, Areas
of 1% annual chance flood with average
depth less than one foot or with drainage
areas of less than one square mile zone x
% Future Conditions 1% Annual
Chance Flood Hazard ZoneX
Area with Reduced Flood Risk due to
Levee. See Notes. zone x
Area with Flood Risk due to Levee zone o
NO SCREEN Area of Minimal Flood Hazard zonex
Effective LOMRs
Area of Undetermined Flood Hazard Zone D
- — - - Channel, Culvert, or Storm Sewer
Willi Levee, Dike, or Floodwall
O 20.2 Cross Sections with 1% Annual Chance
17S Water Surface Elevation
o - - - Coastal Transect
+ au Base Flood Elevation Line (BFE)
Limit of Study
Jurisdiction Boundary
Coastal Transect Baseline
- - Profile Baseline
Hydrographic Feature
Digital Data Available
No Digital Data Available
Unmapped
The pin displayed on the map is an approximate
point selected by the user and does not represent
an authoritative property location.

This map complies with FEMA's standards for the use of
digital flood maps if it is not void as described below.

The basemap shown complies with FEMA's basemap
accuracy standards
The flood hazard information is derived directly from the authoritative NFHL web services provided by FEMA. This map was exported on 6/11/2024 at 4:17 PM and does not
reflect changes or amendments subsequent to this date and time. The NFHL and effective information may change or
become superseded by new data over time.

This map image is void if the one or more of the following map elements do not appear: basemap imagery, flood zone labels, legend, scale bar, map creation date, community identifiers, FIRM panel number, and FIRM effective date. Map images for unmapped and unmodernized areas cannot be used for
regulatory purposes.

Basemap Imagery Source: USGS National Map 2023

33° 45 57" N
S
v
0 Hydrologic Soil Group —Riverside County, Coachella Valley Area, California (North Area)
Map Scale: 1:2,470 if printed on A portrait (8.5" x 11") sheet, 35 70
140
552100
Meters
210
Feet
0 100 200 403 600
Map projection: Web Mercator Comer coordinates: WGS84 Edge tics: UTM Zone 11N WGS84 552160
552160
USDA Natural Resources
Conservation Service National Cho erati4e5il Survey
1/4/2024

Page 1 of 4 ends

Hydrologic Soil Group —Riverside County, Coachella Valley Area, California (North Area)

MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Rating Polygons
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Soil Rating Lines
0 -• A
A/D
•�_� C/D
D
r Not rated or not available
Soil Rating Points
▪ A
O
■
•
A/D
B
B/D
o C/D
� D
▪ Not rated or not available
Water Features
Streams and Canals
Transportation
▪ } - Rails
ti Interstate Highways
US Routes
Major Roads
Local Roads
Background
Aerial Photography
The soil surveys that comprise your AOI were mapped at
1:24,000.

Warning: Soil Map may not be valid at this scale.

Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale.

Please rely on the bar scale on each map sheet for map
measurements.

Source of Map: Natural Resources Conservation Service
Web Soil Survey URL:

Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required.

This product is generated from the USDA-NRCS certified data as of the version date(s) listed below.

Soil Survey Area: Riverside County, Coachella Valley Area, California
Survey Area Data: Version 15, Aug 30, 2023
Soil map units are labeled (as space allows) for map scales 1:50,000 or larger.

Date(s) aerial images were photographed: Mar 15, 2022 —May 28, 2022
The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident.

USDA Natural Resources
Conservation Service
b il u
Nationall2ati4e6il Survey
1 /4/2024

Page 2 of 4 ends

Hydrologic Soil Group —Riverside County, Coachella Valley Area, California North Area
Hydrologic Soil Group
Map unit symbol
Map unit name
Rating
Acres in AOI
Percent of AOI
CpA
Coachella fine sand, 0
to 2 percent slopes
A

13.0 100.0%
Totals for Area of Interest

13.0 100.0%
Description
Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation, are thoroughly wet, and receive precipitation from long -duration storms.

The soils in the United States are assigned to four groups (A, B, C, and D) and three dual classes (A/D, B/D, and C/D). The groups are defined as follows:

Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission.

Group B. Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture.

These soils have a moderate rate of water transmission.

Group C. Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission.

Group D. Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These consist chiefly of clays that have a high shrink -swell potential, soils that have a high water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission.

If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is for drained areas and the second is for undrained areas. Only the soils that in their natural condition are in group D are assigned to dual classes.

Rating Options
Aggregation Method: Dominant Condition
Component Percent Cutoff. None Specified
USDA Natural Resources Web Soil Survey
Conservation Service National Cooperative Soil Survey
1/4/2024

Page 3 of 4 ends

1217

33° 46' 0" N
33° 45 53" N
N
551810
551870
Hydrologic Soil Group —Riverside County, Coachella Valley Area, California (South Area)
551930
551990
551870 551900 551930 551960 551990 552020 552050 552080 Map Scale: 1:1,660 if printed on A landscape (11" x 8.5") sheet. 0 20 40
Feet
0 50 100 200 300
Map projection: Web Mercator Comer coordinates: WGS84 Edge tics: UTM Zone 11N WGS84 80 Meters
120
552110
552110
33° 46' 0" N
33° 45 53" N
USDA Natural Resources
Conservation Service
b il u
Nationall2ati4e8il Survey
1/4/2024

Page 1 of 4 ends

Hydrologic Soil Group —Riverside County, Coachella Valley Area, California (South Area)

Warning: Soil Map may not be valid at this scale.

Please rely on the bar scale on each map sheet for map
measurements.

Source of Map: Natural Resources Conservation Service
Web Soil Survey URL:

This product is generated from the USDA-NRCS certified data as of the version date(s) listed below.

Soil Survey Area: Riverside County, Coachella Valley Area, California
Survey Area Data: Version 15, Aug 30, 2023
Soil map units are labeled (as space allows) for map scales 1:50,000 or larger.

USDA Natural Resources
Conservation Service
b d u
National C6o ati4e9bil Survey
1/4/2024

Page 2 of 4 ends

Hydrologic Soil Group —Riverside County, Coachella Valley Area, California South Area
Hydrologic Soil Group
Map unit symbol
Map unit name
Rating
Acres in AOI
Percent of AOI
CpA
Coachella fine sand, 0
to 2 percent slopes
A

7.1 100.0%
Totals for Area of Interest

7.1 100.0%
Description
Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation, are thoroughly wet, and receive precipitation from long -duration storms.

The soils in the United States are assigned to four groups (A, B, C, and D) and three dual classes (A/D, B/D, and C/D). The groups are defined as follows:

These soils have a moderate rate of water transmission.

Rating Options
Aggregation Method: Dominant Condition
Component Percent Cutoff. None Specified
USDA Natural Resources Web Soil Survey
Conservation Service National Cooperative Soil Survey
1/4/2024

Page 3 of 4 ends

1220

NOAA Atlas 14, Volume 6, Version 2
Location name: Rancho Mirage, California, USA*
Latitude: 33.767°, Longitude: -116.4389°
Elevation: 260 ft**
* source: ESRI Maps
** source: USGS

POINT PRECIPITATION FREQUENCY ESTIMATES
Sanja Perica, Sarah Dietz, Sarah Heim, Lillian Hiner, Kazungu Maitaria, Deborah Martin, Sandra Pavlovic, Ishani Roy, Carl Trypaluk, Dale Unruh, Fenglin Yen, Michael Yekta, Tan Zhao, Geoffrey Bonnin, Daniel Brewer, Li-Chuan Chen, Tye Parzybok, John Yarchoan NOAA, National Weather Service, Silver Spring, Maryland PF tabular I PF graphical I Maps & aerials
PF tabular
PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches)1 Duration
5 -min
10 -min
15 -min
30 -min
60 -min
2 -hr
3 -hr
6 -hr
12 -hr
24 -hr
2 -day
3 -day
4 -day
7 -day
10 -day
20 -day
30 -day
45 -day
60 -day
Average recurrence interval (years)
1 2

0.072
(0.060-0.087)

0.117
(0.097-0.142)

0.103
(0.086-0.124)

0.168
(0.140-0.203)

0.124
(0.104-0.150)

0.203
(0.169-0.246)

0.202
(0.169-0.245)

0.330
(0.275-0.400)

0.279
(0.233-0.338)

0.455
(0.379-0.552)

0.374
(0.312-0.453)

0.611
(0.509-0.741)

0.443
(0.369-0.536)

0.721
(0.601-0.875)

0.593
(0.494-0.718)

0.953
(0.794-1.16)

0.733
(0.611-0.888)

1.16 (0.969-1.41)

0.867
(0.768-1.00)

1.36 (1.20-1.57)

0.996
(0.882-1.15)

1.54 (1.36-1.78)

1.06 (0.937-1.22)

1.63 (1.44-1.88)

1.09 (0.966-1.26)

1.67 (1.48-1.93)

1.19 (1.05-1.37)

1.82 (1.61-2.10)

1.26 (1.11-1.45)

1.93 (1.70-2.22)

1.38 (1.22-1.60)
2,14
(1.89-2.47)

1.55 (1.37-1.79)

2.42 (2.14-2.79)

1.70 (1.51-1.97)

2.69 (2.38-3.10)

1.83 (1.62-2.11)

2.91 (2.58-3.36)
5 0.190
(0.157-0.231)

0.272
(0.226-0.330)

0.329
(0.273-0.400)

0.535
(0.444-0.650)

0.738
(0.613-0.898)

0.969
(0.805-1.18)

1.13 (0.940-1.38)

1.47 (1.22-1.79)

1.77 (1.47-2.15)

2.06 (1.81-2.38)

2.32 (2.04-2.68)

2.44 (2.15-2.83)

2.51 (2.21-2.90)

2.73 (2.40-3.16)

2.89 (2.55-3.34)

3.23 (2.85-3.74)

3.68 (3.24-4.26)

4.12 (3.64-4.77)

4.50 (3.97-5.22)
10 0.260
(0.214-0.319)

0.373
(0.307-0.458)

0.451
(0.372-0.553)

0.734
(0.605-0.900)

1.01 (0.835-1.24)

1.30 (1.07-1.60)

1.50 (1.24-1.84)

1.93 (1.59-2.36)

2.30 (1.90-2.82)

2.66 (2.33-3.10)

2.99 (2.62-3.49)

3.16 (2.76-3.68)

3.24 (2.84-3.78)

3.52 (3.08-4.11)

3.74 (3.27-4.36)

4.20 (3.67-4.90)

4.80 (4.20-5.61)

5.41 (4.73-6.32)

5.94 (5.20-6.93)
25 0.378
(0.301-0.479)

0.541
(0.431-0.687)

0.655
(0.521-0.831)

1.06 (0.848-1.35)

1.47 (1.17-1.87)

1.82 (1.45-2.31)

2.07 (1.65-2.62)

2.60 (2.07-3.30)

3.08 (2.45-3.91)

3.54 (3.00-4.26)

3.98 (3.37-4.80)

4.21 (3.57-5.07)

4.33 (3.67-5.22)

4.71 (3.99-5.67)

5.00 (4.24-6.02)

5.65 (4.78-6.80)

6.49 (5.50-7.82)

7.36 (6.24-8.86)

8.12 (6.88-9.77)
50 0.488
(0.380-0.632)

0.699
(0.544-0.906)
100
200
500
1000

0.620
(0.471-0.824)

0.800
(0.590-1.09)

1.27 (0.901-1.82)

1.81 1.24-2.68)

0.888
(0.675-1.18)

1.15 (0.846-1.57)

1.83 (1.29-2.61)

2.60 (1.78-3.84)

0.845
(0.658-1.10)

1.07 (0.816-1.43)

1.39 (1.02-1.90)

2.21 (1.56-3.15)

3.14 2.15-4.65)

1.38 (1.07-1.78)

1.90 (1.48-2.46)

2.28 (1.77-2.95)

1.75 (1.33-2.32)

2.26 (1.66-3.09)

3.59 (2.54-5.13)

5.12 (3.49-7.56)

2.41 (1.83-3.21)

3.12 (2.30-4.26)

4.96 (3.51-7.08)

7.06 4.83-10.4)

2.80 (2.13-3.72)

3.40 (2.51-4.66)

5.01 (3.55-7.15)

7.14 (4.87-10.6)

2.56 (1.99-3.31)

3.10 (2.36-4.12)

3.72 (2.75-5.09)

5.06 (3.58-7.22)

7.21 4.92-10.7)

3.17 (2.47-4.11)

3.72 (2.90-4.83)

4.27 (3.54-5.24)

3.79 (2.88-5.04)

4.48 (3.31-6.14)

5.51 (3.90-7.86)

7.28 (4.97-10.8)

4.42 (3.36-5.88)

5.19 (3.83-7.10)

6.31 (4.46-9.00)

7.35 5.02-10.9)

5.05 (4.10-6.36)

5.91 (4.66-7.64)

7.16 (5.43-9.63)

8.20 (6.02-11.4)

4.80 (3.99-5.90)

5.69 (4.62-7.16)

6.67 (5.26-8.62)

8.09 (6.14-10.9)

9.28 6.81-12.9)

5.09 (4.23-6.26)

5.24 (4.35-6.44)

5.70 (4.73-7.00)

6.05 (4.91-7.62)

7.11 (5.62-9.20)

8.67 (6.58-11.7)

9.99 (7.33-13.9)

6.24 (5.06-7.85)

7.34 (5.80-9.49)

8.97 (6.80-12.1)

10.4 7.59-14.4)

6.78 (5.50-8.54)

7.98 (6.30-10.3)

9.76 (7.40-13.1)

11.3 (8.25-15.7)

6.06 (5.03-7.44)

7.21 (5.84-9.07)

8.48 (6.70-11.0)

10.4 (7.86-14.0)

12.0 8.77-16.6)

6.86 (5.70-8.44)

7.92 (6.57-9.73)

9.02 (7.48-11.1)

8.20 (6.65-10.3)

9.68 (7.64-12.5)

11.9 (9.00-16.0)

13.7 (10.1-19.1)
9A8
(7.69-11.9)

11.2 (8.86-14.5)

13.8 (10.5-18.6)

16.0 (11.7-22.3)

10.8 (8.79-13.6)

12.9 (10.2-16.7)

15.9 (12.1-21.4)

18.5 (13.6-25.8)

9.98 (8.28-12.3)

12.0 (9.76-15.1)

14.3 (11.3-18.5)

17.8 (13.5-24.0)

20.8 15.2-28.9)
1 Precipitation frequency (PF) estimates in this table are based on frequency analysis of partial duration series (PDS).

Numbers in parenthesis are PF estimates at lower and upper bounds of the 90% confidence interval. The probability that precipitation frequency estimates (for a given duration and average recurrence interval) will be greater than the upper bound (or less than the lower bound) is 5%. Estimates at upper bounds are not checked against probable maximum precipitation (PMP) estimates and may be higher than currently valid PMP values.

Please refer to NOAA Atlas 14 document for more information.

PDS-based depth -duration -frequency (DDF) curves
Latitude: 33.7670°, Longitude: -116.4389°
20 — 15
0 :1
4 10
0 E
t
kki
- t
Duration
• f F, rD ri
• ro
"Cl -CI Z7 -CI
A p
2 5 i0 25 50 100 200 500 1000
NOM Atlas 14, Volume 6„ Version 2
Average recurrence interval years)
Created (GMT( Turn May 7 22:42:13 2024
Back to Top
Maps & aerials
Small scale terrain
Cathedral City.
3km
rl
2mi
�Ftancho
NI [rage
Average recurrence
interval
(years),
— 1
2 — 5
— 10
— 25
50 — 100
— 200
500
— 1000
Duration
5-mNt
10 -min
I5 -min
30 -min
80 -min
2 -hr
3-11[
6 -hr
12 -hr
24-4 r
2 -day
3 -day
4 -day
7 -day
10 -day
20 -day
30 -day
46 -day
60 -day
Laiie2a2e2in

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Palmdale
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DS Angeles Riverside rf G6, •
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•
santa• Ane Palm Deseri •Indio
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Oceanside •
100km
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n Diego
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•
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ma
•
Large scale map
ancaster
.;Palmdale Victcrvi[le
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Los Angeles
0 r. Riveraicle
ft Anaheim {; the€Irat
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e w•Jn€lio
—Santa Arta ',alM Desert
"' Murrieta
Oceanside
100km
60mi
Large scale aerial
legit Yuma
L.

H
Back to Top
US Department of Commerce
National Oceanic and Atmospheric Administration
National Weather Service
National Water Center
1325 East West Highway
Silver Spring, MD 20910
Questions?: HDSC.Questions(&noaa.gov
Disclaimer
1223

CITY OF RANCH MIRAGE
15' MIN.

AT ACCESS SIDE
Co ▪ z
co
U m
Q
W
F !Li)
L▪ )
J Cj
Q
10 O

SLOPE TO DRAIN
2:1*
MAX.

L2
Li
s
LABEL TOP BANK ELEV. (ALL CORNERS) SLOPE TO DRAIN
100 YR. SURFACE ELEV @ 2% TYP. BUILDING
MAX. DEPTH FS=1.

DESIGN CRITERIA
1' MIN. "FREEBOARD"

FROM BUILDING PAD
MAX. PERCOLATION RATE = 1 "/HR.

MAX. DEPTH AT PEAK STORAGE = 5'
FACTOR OF SAFETY F.S. = 1.0 MINIMUM
ONE FOOT MINIMUM "FREEBOARD" BELOW LOWEST BUILDING PAD TO MAXIMUM WATER LEVEL THE BASIN SHALL BE DESIGNED TO RETAIN THE RUNOFF FROM THE WORST CASE OF THE 1 HR., ,3 HR. 6 HR., OR 24 HR. DURATION, 100 YEAR FREQUENCY STORM.

SEE SHT. 2 OF 2 FOR MINIMUM PLAN REQUIREMENTS
* SLOPES STEEPER THAN 5:1 WILL REQUIRE EROSION CONTROL APPROVED BY THE CITY ENGINEER. (TYPICAL EROSION CONTROL CONSISTS OF CONTINUOUS GROUND COVER LIKE GRASS, OR WASHED ROCK WITH A DIAMETER OF 1" OR LARGER, PLACED TO A DEPTH OF 3" OVER WEED BARRIER CLOTH.)

CITY OF RANCHO MIRAGE

REVISIONS
* 7/5/2012

RETENTION BASIN
�✓` `.►1 7 /A2// -L-
APPROVED : Y: CITY ENGINEER DATE
i _

STANDARD
DETAIL
31 0
SHT. 1 OF 2
A

CITY OF RANCH MIRAGE
AT A MINIMUM. PLANS SHALL INCLUDE THE FOLLOWING INFORMATION:

1. BOUNDARY (LOT LINES) INCLUDING BEARING AND DISTANCES

2. SLOPE SYMBOLS, OR FINISH CONTOURS, WITH SLOPE RATIOS OR PERCENTAGES * 3. ELEVATION LABELS FOR: BOTTOM, WATER SURFACE AT VOL. MAX. FOR 100YR. STORM, AND TOP (HYDROLOGY CALCULATIONS SHALL BE SUBMITTED VERIFYING BASIN AREA, DEPTH, AND VOLUME.)

4. DIMENSIONS (LENGTH, WIDTH AND DEPTH) OR SCALED DRAWING.

5. FINISHED SURFACE ELEVATIONS FOR IDENTIFYING THE FLOW PATHS

6. RIP -RAP OR APPROPRIATE EROSION CONTROL IF SLOPES EXCEED 20% (5:1)

7. ANY STRUCTURES, PIPES, HEADWALLS, RIP -RAP, DRYWELLS, ETC. SHOWN WITH

REFERENCE TO STREET PLANS, STORM DRAIN PLANS, OR GRADING PLANS (A DRYWELL IS RECOMMENDED FOR LARGER RETENTION BASINS AS A WAY OF INTERCEPTING "NUISANCE WATER' THAT MIGHT CAUSE A CONSTANT SWAMPY AREA TO DEVELOP IN THE RETENTION BASIN. FLOWS TO CVWD CHANNELS OR TO LAKES TYPICALLY REQUIRE A DRYWELL TO INTERCEPT STREET RUNOFF. MAINTENANCE IS EASIEST IF THE DRYWELL IS NEAR THE STREET SO VACUUM TRUCKS CAN ACCESS THEM.

SEE STANDARD DRAWINGS 306 AND 311.)

CITY OF RANCHO MIRAGE

REVISIONS
* 7/5/2012

RETENTION BASIN NOTES
7/airt_
AP OVED BY: C ITY ENGINEER DATE

STANDARD
DETAIL
31 0
SHT. 2 OF 2
1225

ACTUAL IMPERVIOUS COVER
Land Use (1)
Range -Percent
Recommended Value
For Average
Conditions-Percent(2;
Natural or Agriculture
Single Family Residential: (3)
40,000 S. F. (1 Acre) Lots
20,000 S. F. (1 Acre) Lots
7,200 - 10,000 S. F. Lots
Multiple Family Residential:

Condominiums
Apartments
Mobile Home Park
Commercial, Downtown
Business or Industrial
0 - 10
10 - 25
30 - 45
45 - 55
45 - 70
65 - 90
60 - 85
80 -100
0 20
40 50
65 80
75 90
Notes:

1. Land use should be based on ultimate development of the watershed.

Long range master plans for the County and incorporated cities should be reviewed to insure reasonable land use assumptions.

2. Recommended values are based on average conditions which may not apply to a particular study area. The percentage impervious may vary greatly even on comparable sized lots due to differences in dwelling size, improvements, etc. Landscape practices should also be considered as it is common in some areas to use ornamental grav- els underlain by impervious plastic materials in place of lawns and shrubs. A field investigation of a study area should always be made, and a review of aerial photos, where available may assist in estimat- ing the percentage of impervious cover in developed areas.

3. For typical horse ranch subdivisions increase impervious area 5 per- cent over the values recommended in the table above.

RCFC & WCD
HYDROLOGY 1M/MA NUAL

IMPERVIOUS COVER
FOR

DEVELOPED AREAS
1226
PLATE D-5.6

RUNOFF INDEX NUMBERS OF HYDROLOGIC SOIL -COVER COMPLEXES FOR PERVIOUS AREAS -AMC II Cover Type (3)
Quality of
Cover (2)
Soil Group
A
B
C
D

NATURAL COVERS -
Poor
78 53
86 70
91 80
93 85
Barren
(Rockland, eroded and graded land)
Chaparrel, Broadleaf
(Manzonita, ceanothus and scrub oak)
Fair
40 63
75 81
Good
31 57
71 78
Chaparrel, Narrowleaf
Poor
71 82
88 91
(Chamise and redshank)
Fair
55 72
81 86
Grass, Annual or Perennial
Poor
67 78
86 89
Fair
50 69
79 84
Good
38 61
74 80
Meadows or Cienegas
Poor
63 77
85 88
(Areas with seasonally high water table,
Fair
51 70
80 84
principal vegetation is sod forming grass)
Good
30 58
72 78
Open Brush
Poor
62 76
84 88
(Soft wood shrubs - buckwheat, sage, etc.)
Fair
46 66
77 83
Good
41 63
75 81
Woodland
Poor
45 66
77 83
(Coniferous or broadleaf trees predominate.

Fair
36 60
73 79
Canopy density is at least 50 percent)
Good
28 55
70 77
Woodland, Grass
Poor
57 73
82 86
(Coniferous or broadleaf trees with canopy
Fair
44 65
77 82
density from 20 to 50 percent)
Good
33 58
72 79

URBAN COVERS -
Good
Poor
32 58
56 74
69 83
75 87
Residential or Commercial Landscaping
(Lawn, shrubs, etc.)
Turf
(Irrigated and mowed grass)
Fair
44 65
77 82
Good
33 58
72 79

AGRICULTURAL COVERS -
76 85
90 92
Fallow
(Land plowed but not tilled or seeded)

R C F C & W C D
�J'

HYDROLOGY MANUAL

RUNOFF INDEX NUMBERS
FOR

PERVIOUS AREA
1227
PLATE D-5.5 (I of 2)

-o
r
rn
m
m
c
4 -n
z y
13 x m
zi'-lg1__'.10
m
c
(n
ln
o
z
m
..n
O
20 1.0
.9
.8
.7
NOTES:

I. R.I. Number -Infiltration relationships are derived from rainfall - runoff relationships in Bibliography item No.36.
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228

1 of 6

HYDROLOGY CALCULATIONS -
Using the RCFC&V\CD Short Cut Unit Hydrograph Method
Area Designations Prea 1 VERSION 2
Area=1.00ac+0.09actyp street frontage=1.09ac
57/2024 LOT 1
DrainageArea(ac.) 1.0900 JOB NUM3ER 22106
Unit tine (rrinutes) 5 5 5 15
100 Year Storm Duration (hrs) 1 3 6 24
Total Predpitaticn (Plates D -4.4,E-5.2, 5.4, 5.6)(in.) 2.41 3.10 3.79 5.05 from NQAA interactive website Soils Gaup A
MAC index II Runoff Nurrber (plate E-6.1) 32
Rate E-6.2 Pervious Area Lass Rate (Fp)(in(Ir) 0.74 (AMC II) Percentage of Inpervious Cover (A)(%) (plate E-6.3) 26.6 20% per the RCFC Hydrology Manual 1AC LOT -PLATE D 5.6 AND 0.09AC TYPICAL STREET FRONTAGE V\kighted Average res Rate (F=Fp(1-.9A))(in./hr.) 0.56 (used for 1, 3, and 6 hour storm the 24 hour storm uses variable maximum loss rate per plate E-1.1 (3 of 6)) Low Loss Rate Percent (%) 90
Retention Basin Peroolation Rate (in/hr) 0.01 (also used for drywall pennlation rate) Percolation is taken incrementally.

Basin volume is calculated using the"truncated pyramid" formula, a more conservative estimate than "averaged end areas" sometir used program updated 4-14-22 LC
(DrywelI can be "zeroed out" by reducing numbers to less than .001, but should not entered as zeros or program chokes.) DrywelI storage indudes 40%of the 1' wide rock bed surrounding the drywall: formula (upperrPftr(diam/2)A2+(lower)*Pft)*((diam/2r2+0.41(diam/2+(grav+0.4166))"2-(diam/2+0.4166)A2)) The drywall wall thickness is assumed at 5" (0.4166) and the gravel bed width is variable "gray" Drywell iS zeroed out by reducing to 0.001 since there is none.

Drywell design factors Upper sec. (ft.)= 0.001 Lower sec. (ft.)= 0.001 Ring diam. (ft.) = 0.001 Drywell lower max. (cf)= 0.00 Upper max.(cf)= 0.00 Gavel bed width around drywalI= 0.001
Drywall total(cf)= 0.00
Ret. Basin design (area, depth) Top = 3702 s.f. Bot. = 1062 s.f. Max. Depth (d)= 4 Max. storage= 8995.74 (d/3)*(bottomi-topF(bottorrfltoprO.50) Formulas vol(h/3)*(bottom+top+(bottom*top)A0.50) area400ttor +(h/d)*(top-bottom) h=(vol*3)/(bottom+top+(bottom*top)A0.5) (values must be non -zero or error occurs) Outside input from: N/A 3.25
1 Hour Storm in 5 minute increments Drywall Drywall Drywall Drywall Overflow Basin Basin Basin Tirre Pattern Storm I nos Rate Value Effective Flow Flaw Outside Retention Pedal Storage Storage To Retention Period Storage Storage Overflow Overflow % Rain (ir✓hr Max. Mn. Ran (in/hr Rate (cfs) Vd. (cf) Input (cf) Area (sf) Pam. (d; Vd. (cf) Depth (ft) Basin (cf) Area (sf) Pero. (cf) Vd. (d) Depth (ft Vd. (d) Rate (cfs) 0:05 3.7 1.0700 0.5628 N/A 0.5072 0.5575 167.24 0.00 a00 0.00 0.00 0.00 167.24 106200 0.07 167.16 0.07 0.00 0.00 0:10 4.8 1.38PO 0.5678 N/A 0.8253 0.9071 272.13 0.00 0.00 0.00 0.00 0.00 272.13 1111.06 0.08 439.21 0.20 0.00 0.00 0:15 5.1 14749 0.5628 N/A 0.9121 1.0024 300.73 0.00 a00 0.00 0.00 0.00 300.73 1190.90 0.08 739.86 0.33 0.00 0.00 0:20 4.9 1.4171 0.5678 N/A 0.8542 0.9389 281.66 0.00 0.00 0.00 0.00 0.00 281.66 1279.13 0.09 1021.44 0.45 0.00 0.00 0:25 6.6 1.9087 0.5628 N/A 1.3459 1.4792 443.77 0.00 a00 0.00 0.00 0.00 443.77 1361.76 0.09 1465.11 0.65 0.00 0.00 0:30 7.3 21112 0.5678 N/A 1.5483 1.7017 510.52 0.00 0.00 0.00 0.00 0.00 510.52 1491.97 0.10 1975.53 0.88 0.00 0.00 0:35 8.4 2.4293 0.5628 N/A 1.8664 20514 615.41 0.00 a00 0.00 0.00 0.00 615.41 1641.76 0.11 2590.82 1.15 0.00 0.00 0:40 9 2.6028 0.5628 N/A 2.0400 2.2421 672.62 0.00 0.00 0.00 0.00 0.00 67262 182233 0.13 3263.32 1.45 0.00 0.00 0:45 12.3 3.5572 0.5628 N/A 2.9943 3.2910 987.30 0.00 0.00 0.00 0.00 0.00 98730 2019.69 0.14 4250.48 1.89 0.00 0.00 0:50 17.6 5.0899 0.5628 N/A 4.5271 4.9756 1492.69 0.00 0.00 0.00 0.00 0.00 149269 2309.40 0.16 5743.01 255 0.00 0.00 0:55 16.1 4.6561 0.5628 N/A 4.0933 4.4989 1349.66 0.00 0.00 0.00 0.00 0.00 1349.66 2747.41 0.19 7092.48 a15 0.00 0.00 1:00 4.2 1.2146 0.5628 N/A 0.6518 0.7164 214.91 0.00 0.00 0.00 0.00 0.00 214.91 3143.44 0.22 7307.17 3.25 0.00 0.00 MAX DEPTH 0 0.0000 0.5628 0.00 0.0000 0.0000 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3206.45 0.22 7306.95 3.25 0.00 0.00 0 0.0000 0.5628 0.00 0.0000 0.0000 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3206.39 0.22 7306.73 3.25 0.00 0.00 1:15 0 0.0000 0.5628 0.00 0.0000 0.0000 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3206.32 0.22 7306.50 3.25 0.00 0.00 Total volume (cf) 7308.64 Total Overflow(cf) 0.00
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1 of6

HYDROLOGY CALCULATIONS -
Using the RCFC&V\CD Short Cut Unit Hydrograph Method
Area Designations Area 1 VERSION 2
Area=1.07ac+0.09ac typ street frontage=1.16ac
57/2024 LOT 2
Drainage Area (ac.) 1.1600 JOB NUM3ER22106
Unit tine (rrinutes) 5 5 5 15
100 Year Storm Duration (hrs) 1 3 6 24
Total Precipitation (Plates D -4.4,E-5.2, 5.4, 5.6)(in.) 2.41 3.10 179 5.05 from NOAA interactive website Sals Croup A
MAC index II Runoff Nurrber (plate E-6.1) 32
Rate E-6.2 Pervious Area Lass Rate (Fp)(ir✓Ir) 0.74 (AMC II) Percentage of InperWous Cover (A)(%) (plate E-6.3) 26.6 20% per the RCFC Hydrology Manuel 1AC LOT -PLATE D 5.6 AND 0.09AC TYPICAL STREET FRONTAGE V'ikighted Average toss Rate (F=Fp(1-.9A))(in./hr.) 0.56 (used for 1, 3, and 6 hour storm the 24 hour storm uses variable maximum Ices rate per plate E-1.1 (3 of 6)) Low Loss Rate Percent (%) 90
Retention Basin Peroolation Rate (in/hr) 0.01 (also used for drywell percdation rate) Percolation is taken incrementally.

Basin volume is calculated using the"truncated pyramid" formula, a more conservative estimate than "averaged end areas" sometiute used program updated 4-14-22 LC
(DrywelI can be "zeroed out" by reducing numbers to less than .001, but should not entered as zeros or program chokes.) DrywelI storage indudes 40%of the 1' wide rock bed surrounding the drywall: formula (upperrPftr(diam/2)A2+(lower)*R0*((diam/2)A2+0.41(diam/2+(grav+0.4166))"2-(diam/2+0.4166)A2)) The drywall wall thickness is assumed at 5" (0.4166) and the gravel bed width is variable "gray" Drywell is zeroed out by reducing to 0.001 since there is none.

Drywell design factors Upper sec. (ft.)= 0.001 Lower sec. (ft.)= 0.001 Ring diam. (ft.) = 0.001 Drywell lower max. (cf)= 0.00 Upper max.(cf)= 0.00 Craver bed width around drywell= 0.001
DrywalI total (cf )= 0.00
Ret. Basin design (area, depth) Top = 3234 s.f. Bot. = 1078 s.f. Max. Depth (d)= 4 Max. storage= 8238.87 (dr3)*(bottom+top+(bottorrilop)'0.50) Formulas vol(h/3)*(bottom+top+(bottomotop)A0.50) are =bottom+(h/d)*(top-bottom) h=(vol"3)/(bottom+top+(bottomlop)A0.5) (values must be non -zero or error occurs) Outside input from: N/A 125
1 Hour Storm in 5 minute increments Drywall Drywall Drywall Drywall Overflow Basin Basin Basin Tine Pattern Storm I res Rate Value Effective Aces Row Outside Retention Period Storage Storage To Retention Period Storage Storage Overflow Overflow % Rain (inihr Max. Mn. Ran (in/hr Rate (cfs) Vd. (cf) Input (cf) Area (sf) Parc. (cf, Vd. (cf) Depth (ft) Basin (cf) Area (sf) Pert. (cf) Vol. (cf) Depth (ft Vol. (cf) Rate (cfs) 0:05 17 1.0700 0.5628 N/A 0.5072 0.5933 177.98 0.00 0.00 0.00 0.00 0.00 177.98 1078.00 0.07 177.90 0.09 0.00 0.00 0:10 4.8 1.18P0 0.5628 N/A 0.8253 0.9653 289.60 0.00 0.00 0.00 0.00 0.00 289.60 1124.55 0.08 467.43 0.23 0.00 0.00 0:15 5.1 1.4749 0.5628 N/A 0.9121 1.0668 320.05 0.00 0.00 0.00 0.00 0.00 320.05 1200.32 0.08 787.39 0.38 0.00 0.00 0:20 4.9 1.4171 0.5628 N/A 0.8542 0.9992 299.75 0.00 0.00 0.00 0.00 0.00 299.75 1284.05 0.09 1087.05 0.53 0.00 0.00 0:25 6.6 1.9087 0.5628 N/A 1.3459 1.5742 472.27 0.00 0.00 0.00 0.00 0.00 472.27 1362.47 0.09 1559.23 0.76 0.00 0.00 0:30 7.3 21112 0.5628 N/A 1.5483 1.8110 543.30 0.00 0.00 0.00 0.00 0.00 543.30 1486.03 0.10 2102.43 1.02 0.00 0.00 0:35 54 2.4293 0.5628 N/A 1.8664 2.1831 654.93 0.00 0.00 0.00 0.00 0.00 654.93 1628.18 0.11 2757.25 1.34 0.00 0.00 0:40 9 2.6028 0.5628 N/A 2.0400 2.3861 715.82 0.00 0.00 0.00 0.00 0.00 71182 1799.53 (112 3472.94 1.69 0.00 0.00 0:45 12.3 15572 0.5628 N/A 2.9943 15024 1050.71 0.00 0.00 0.00 0.00 0.00 1050.71 1986.82 0.14 4523.51 2.20 0.00 (100 0:50 17.6 10899 0.5628 N/A 4.5271 5.2952 1588.55 0.00 0.00 0.00 0.00 0.00 1588.55 2261.74 (116 6111.90 2.97 0.00 0.00 0:55 16.1 4.6561 0.5628 N/A 4.0933 4.7878 1436.33 0.00 0.00 0.00 0.00 0.00 1436.33 2677.40 0.19 7548.05 166 0.00 0.00 1:00 4.2 1.2146 0.5628 N/A 0.6518 0.7624 228.72 0.00 0.00 0.00 0.00 0.00 228.72 3053.22 (121 7776.55 3.78 0.00 0.00 MAX DEPTH 0 0.0000 0.5628 0.00 0.0000 0.0000 0.00 0.00 0.00 0.00 0.00 0.00 0.00 311102 0.22 7776.33 178 0.00 0.00 0 0.0000 0.5628 0.00 0.0000 0.0000 0.00 0.00 0.00 0.00 0.00 0.00 0.03 311296 (122 7776.12 3.78 0.00 0.00 1:15 0 0.0000 0.5628 0.00 0.0000 0.0000 0.00 0.00 0.00 0.00 0.00 0.00 0.00 311290 0.22 7775.90 178 0.00 0.00 Total volume (of) 7778.00 Total Overflow (of) 0.00
1235

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24 1 -bur Storm in 15 minute increments Drywall Drywall Drywall Drywell Overflow Basin Basin Basin Time Pattern Storm Loss Rate Value Effective Row Row Outside Retention Penod Storage Storage To Retention Period Storage Storage Overflow Overflow % Rain (irVhr Mex. Mn. Rain (inrhr Rate (cfs) Vd. (cf) Input (ci) Area (sf) Pero. (cf Vol. (ci) Depth (ft) Basin (cf) Area (sf) Perc. (d) Vd. (cf) Depth (ft Vol. (cf) Rate (cfs) 0:15 02 0.04
0:30 (13 0.06
0:45 0.3 0.06
1:00 (14 0.08
1:15 0.3 0.06
1:30 (13 0.06
1:45 0.3 0.06
200 (14 0.08
215 0.4 0.08
230 0.4 0.08
2:45 (15 0.10
a00 0.5 0.10
3:15 (15 0.10
3:30 0.5 0.10
3:45 (15 0.10
4:00 0.6 (112
4:15 (16 0.12
4:30 0.7 0.14
4:45 (17 0.14
5:00 (18 0.16
5:15 0.6 0.12
5:30 0.7 (114
5:45 (18 0.16
6:00 0.8 (116
6:15 (19 0.18
6:30 (19 0.18
6:45 1 0.20
7:00 1 0.20
7:15 1 0.20
7:30 1.1 0.22
7:45 1.2 0.24
8:00 13 026
8:15 1.5 0.30
8:30 1.5 0.30
8:45 1.6 0.32
9:00 1.7 0.34
9:15 1.9 0.38
9:30 2 0.40
9:45 2.1 0.42
10:00 2.2 0.44
10:15 1.5 0.30
10:30 1.5 0.30
10:45 2 0.40
11:00 2 (140
11:15 1.9 0.38
11:30 1.9 (138
11:45 1.7 0.34
12:00 1.8 0.36
12:15 2.5 0.51
12:30 2.6 0.53
12:45 2.8 0.57

0.99 0.04 (10040 (10047 4.25 0.0) 0.00 0.00 0.00 (100 4.25 1078.00 (122 4.03 (1(X) 0.00 0.00

0.98 0.05 (10061 (10071 6.38 0.00 0.00 0.00 0.00 0.03 6.38 1079.05 022 1(118 (100 0.00 (100

0.97 0.05 0.0061 0.0071 6.38 0.00 0.00 0.00 0.00 (100 6.38 1080.66 (123 16.34 0.01 0.00 0.00

0.95 0.07 0.0081 0.0095 8.51 0.00 (100 0.00 0.00 0.00 8.51 108228 023 24.52 0.01 0.00 (100

0.94 0.05 0.0061 (10071 6.38 0.00 0.00 0.00 0.00 (100 6.38 1084.44 0.23 30.77 0.01 0.00 0.00

0.93 0.05 0.0061 0.0071 6.38 0.00 0.00 0.00 0.00 0.03 6.38 1086.05 023 36.92 (102 0.00 (100

0.92 0.05 0.0061 0.0071 6.38 0.00 0.00 0.00 0.00 (100 6.38 1087.66 (123 43.08 0.02 0.00 0.00

0.91 0.07 0.0081 0.0395 8.51 0.00 0.00 0.00 0.00 0.03 8.51 1089.27 023 51.36 (102 0.00 (100

0.90 (107 0.0081 0.0095 8.51 0.00 0.00 0.00 0.00 (100 8.51 1091.44 (123 59.63 0.03 (100 (100

0.89 0.07 0.0081 0.0095 8.51 0.00 0.00 0.00 0.00 0.00 8.51 1093.61 (123 67.91 (103 0.00 (100

0.:: 0.09 (10101 0.0118 10.63 0.00 0.00 (100 0.00 (100 10.63 1095.77 (123 78.32 (104 (100 0.00

0.87 0.09 0.0101 0.0118 10.63 0.00 0.00 0.00 0.00 0.00 1(163 1098.49 (123 88.72 (104 (100 (100

0.85 0.09 (10101 (10118 10.63 0.00 0.00 0.00 0.00 0.00 10.63 1101.22 (123 99.12 (105 (100 0.00

0.84 0.09 0.0101 0.0118 10.63 0.00 0.00 0.00 0.00 0.00 1(163 1103.94 (123 109.52 (105 (100 0.00

0.83 0.09 (10101 0.0118 10.63 0.00 0.00 (100 0.00 0.00 10.63 1106.66 (123 119.93 (106 (100 0.00

0.82 0.11 0.0121 0.0142 12.76 0.00 0.00 0.00 0.00 0.03 1276 1109.38 (123 132.45 (106 0.0) 0.00

0.81 0.11 (10121 0.0142 12.76 0.00 0.00 (100 0.00 0.00 12.76 1112.66 (123 144.98 (107 (100 0.00

0.80 0.13 0.0141 (10165 14.89 0.00 0.00 0.00 0.00 0.00 14.89 1115.94 (123 159.63 (108 (100 0.00

0.79 0.13 (10141 0.0165 14.89 0.00 0.00 0.00 0.00 0.00 14.89 1119.77 (123 174.29 (108 (100 0.00

0.78 0.15 0.0162 (10189 17.01 0.00 0.00 0.00 0.00 0.00 17.01 1123.61 (123 191.06 (109 (100 0.00

0.77 (111 (10121 0.0142 12.76 0.00 0.00 0.00 0.00 0.00 12.76 1128.00 (123 203.59 (110 0.00 0.00

0.76 0.13 0.0141 0.0165 14.89 0.00 0.00 0.00 0.00 0.03 14.89 1131.28 (124 218.24 (111 (100 0.00

0.75 (115 (10162 0.0189 17.01 0.00 0.00 (100 0.00 (100 17.01 1135.11 (124 235.01 (111 0.00 0.00

0.74 0.15 0.0162 0.0189 17.01 0.00 0.00 0.00 0.00 0.03 17.01 1139.50 (124 251.79 (112 (100 0.00

0.73 0.16 0.0182 0.0213 19.14 0.00 0.00 (100 0.00 0.00 19.14 1143.89 (124 270.69 (113 0.00 0.00

0.72 0.16 (10182 (10213 19.14 0.0) (100 0.00 0.00 (100 19.14 1148.83 0.24 289.58 0.14 0.00 0.00

0.71 (118 0.0202 (10236 21.26 0.00 0.00 0.00 0.00 0.00 21.26 1153.78 (124 310.61 (115 0.00 0.00

0.70 0.18 (10202 (10236 21.26 0.00 (100 0.00 0.00 0.00 21.26 1159.28 0.24 331.63 (116 0.00 0.00

0.69 (118 0.0202 (10236 21.26 0.00 0.00 0.00 0.00 0.00 21.26 1164.78 (124 352.65 (117 0.00 0.00

0.68 0.20 (10222 (10260 23.39 0.00 (100 0.00 0.0) 0.00 23.39 1170.28 (124 375.80 (118 0.00 0.00

0.67 0.22 (10242 (10284 25.52 0.00 0.00 0.00 0.00 0.00 25.52 1176.34 (125 401.07 (119 0.00 0.00

0.66 0.24 0.0263 (10307 27.64 0.0) (100 0.00 0.0) 0.00 27.64 118296 (125 428.47 (121 0.00 0.00

0.66 0.27 0.0303 0.0354 31.90 0.00 0.00 0.00 0.00 0.00 31.90 1190.12 (125 460.12 (122 0.00 0.00

0.65 0.27 0.0303 (10354 31.90 0.00 (100 0.00 0.0) 0.00 31.9) 1198.41 (125 491.77 (124 (100 0.00

0.64 0.29 0.0323 0.0378 34.02 0.00 0.00 0.00 0.00 0.00 34.02 1236.69 (125 525.54 (126 0.00 0.00

0.63 0.31 0.(134,3 (10402 36.15 0.00 0.00 0.00 0.0) 0.00 36.15 1215.53 0.25 561.43 027 (100 0.00

0.62 0.35 0.0384 (10449 40.40 0.00 0.00 0.00 0.00 0.00 40.40 1224.92 0.26 601.58 (129 0.00 0.00

0.61 0.36 (10404 (10473 42.53 0.00 (100 0.00 0.0) 0.00 42.53 1235.43 0.26 643.85 (131 0.00 0.00

0.60 0.38 0.0424 (10496 44.66 0.00 0.0) 0.00 0.00 0.00 44.66 1246.49 (126 688.25 (133 0.00 (100

0.59 0.40 (10444 (10520 46.78 0.00 (100 0.00 0.0) 0.00 46.78 1258.11 (126 734.77 036 (100 0.00 (158 0.27 0.0303 0.0354 31.90 0.00 0.00 0.00 0.00 0.00 31.90 1270.28 (126 766.40 (137 (100 0.00

0.58 0.27 (10303 0.0354 31.90 0.00 (100 0.00 0.00 0.00 31.90 1278.56 0.27 798.03 (139 (100 0.00 (157 0.36 0.0404 0.0473 42.53 0.00 0.00 0.00 0.00 0.00 4253 1286.83 (127 840.29 (141 (100 0.00

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0.53 0.33 (10364 0.0425 38.28 0.00 (100 0.00 (1(X) 0.00 38.28 1339.34 0.28 1036.68 0.50 (100 0.00 (152 0.45 0.0505 (10591 53.16 0.00 0.00 0.00 0.00 0.00 53.16 1349.28 0.28 1089.56 0.53 (100 0.00

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1 of 6

HYDROLOGY CALCULATIONS -
Using the RCFC&V\CD Short Cut Unit Hydrograph Method
Area Designations Prea 1 VERSION 2
Area=1.09ac+0.09ac typ street frontage=1.18ac
57/2024 LOT 3
DrainageArea(ac.) 1.1800 JOB NUM3ER22106
Unit tine Minutes) 5 5 5 15
100 Year Storm Duration (hrs) 1 3 6 24
Total Predpitaticn (Plates D -4.4,E-5.2, 5.4, 5.6)(in.) 2.41 3.10 a79 5.05 from NOAA interactive website Soils Group A
MAC index II Runoff Nurrber (plate E-6.1) 32
Rate E-6.2 Pervious Area Lass Rate (Fp)(in(Ir) 0.74 (AMC II) Percentage of Inpervious Cover (A)(%) (plate E-6.3) 26.6 20% per the RCFC Hydrology Manual 1AC LOT -PLATE D 5.6 AND 0.0 1C TYPICAL STREET FRONTAGE V\kighted Average r1Ss Rate (F=Fp(1-.9A))(in./hr.) 0.56 (used for 1, 3, and 6 hour storm the 24 hour storm uses variable maximum loss rate per plate E-1.1 (3 of 6)) Low Loss Rate Percent (%) 90
Retention Basin Peroolation Rate (in/hr) 0.01 (also used for drywall percdation rate) Percolation is taken incrementally.

Basin volume is calculated using the"truncated pyramid" formula, a more conservative estimate than "averaged end areas" sometiute used program updated 4-14-22 LC
(DrywelI can be "zeroed out" by reducing numbers to less than .001, but should not entered as zeros or program chokes.) DrywelI storage indudes 40%of the 1' wide rock bed surrounding the drywall: formula (upperrPftr(diam/2)A2+(lower)*Pft)*((diam/2r2+0.41(diam/2+(grav+0.4166))"2-(diam/2+0.4166)A2)) The drywall wall thickness is assumed at 5" (0.4166) and the gravel bed width is variable "gray" Drywell is zeroed out by reducing to 0.001 since there is none.

Drywell design factors Upper sec. (ft.)= 0.001 Lower sec. (ft.)= 0.001 Ring diam. (ft.) = 0.001 Drywell lower max. (cf)= 0.00 Upper max.(cf)= 0.00 Craver bed width around drywalI= 0.001
Drywall total(cf)= 0.00
Ret. Basin design (area, depth) Top = 3234 s.f. Bot. = 1078 s.f. Max. Depth (d)= 4 Max. storage= 8238.87 (d/3)*(bottomi-topF(bottorriloprO.50) Formulas vol(h/3)*(bottom+top+(bottom*top)A0.50) areaApottor +(h/d)*(top-bottom) h=(vol*3)/(bottom+top+(bottom*top)A0.5) (values must be non -zero or error occurs) Outside input from: N/A 3.25
1 Hour Storm in 5 minute increments Drywall Drywall Drywall Drywall Overflow Basin Basin Basin Tirre Pattem Storm I nos Rate Value Effective Flow Flaw Outside Retention Pedal Storage Storage To Retention Period Storage Storage Overflow Overflow % Rain (ir✓hr Max. Mn. Ran (in/hr Rate (cfs) Vd. (cf) Input (cf) Area (sf) Pam. (cf, Vd. (cf) Depth (ft) Basin (cf) Area (sf) Pero. (cf) Vd. (d) Depth (ft Vol. (d) Rate (cfs) 0:05 3.7 1.0700 0.5628 N/A 0.5072 0.61115 181.04 0.00 a00 0.00 0.00 0.00 181.04 1078.00 0.07 180.97 0.09 0.00 0.00 0:10 4.8 1.18P0 0.5678 N/A 0.8253 0.9820 294.60 0.00 0.00 0.00 0.00 0.00 294.60 1125.36 0.08 475.49 0.23 0.00 0.00 0:15 5.1 1.4749 0.5628 NIA 0.9121 1.(1452 325.57 0.00 a00 0.00 0.00 0.00 325.57 1202.43 0.08 800.97 0.39 0.00 0.00 0:20 4.9 1.4171 0.5678 N/A 0.8542 1.0164 304.92 0.00 0.00 0.00 0.00 0.00 304.92 1287.60 0.09 1106.80 0.54 0.00 0.00 0:25 6.6 1.9087 0.5628 NIA 1.3459 1.6014 480.41 0.00 a00 0.00 0.00 0.00 480.41 1367.37 0.09 1586.11 0.77 0.00 0.00 0:30 7.3 21112 0.5678 N/A 1.5483 1.8422 552.67 0.00 0.00 0.00 0.00 0.00 55267 1493.06 0.10 2138.68 1.04 0.00 0.00 0:35 8.4 2.4293 0.5628 N/A 1.8664 2.2207 666.22 0.00 a00 0.00 0.00 0.00 666.22 1637.66 0.11 2804.79 1.36 0.00 0.00 0:40 9 2.6028 0.5628 N/A 2.0400 2.4272 728.16 0.00 0.00 0.00 0.00 0.00 728.16 1811.98 0.13 3532.83 1.72 0.00 0.00 0:45 12.3 3.5572 0.5628 N/A 2.9943 a5627 1068.82 0.00 0.00 0.00 0.00 0.00 1063.82 200249 0.14 4601.51 2.23 0.00 0.00 0:50 17.6 5.0899 0.5628 N/A 4.5271 5.3865 1615.94 0.00 0.00 0.00 0.00 0.00 1615.94 2282.15 0.16 6217.29 3.02 0.00 0.00 0:55 16.1 4.6561 0.5628 N/A 4.0933 4.8703 1461.09 0.00 0.00 0.00 0.00 0.00 1461.09 2704.98 0.19 7678.20 a73 0.00 0.00 1:00 4.2 1.2146 0.5628 N/A 0.6518 0.7755 232.66 0.00 0.00 0.00 0.00 0.00 232 66 3087.28 0.21 7910.64 3.84 0.00 0.00 MAX DEPTH 0 0.0000 0.5628 0.00 0.0000 0.0000 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3148.11 0.22 7910.43 3.84 0.00 0.00 0 0.0000 0.5628 0.00 0.0000 0.0000 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3148.05 0.22 7910.21 3.84 0.00 0.00 1:15 0 0.0000 0.5628 0.00 0.0000 0.0000 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3147.99 0.22 7909.99 3.84 0.00 0.00 Total volume (cf) 7912.11 Total Overflow(cf) 0.00
1241

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1 of 6

HYDROLOGY CALCULATIONS -
Using the RCFC&V\CD Short Cut Unit Hydrograph Method
Area Designations Prea 1 VERSION 2
Area=1.09ac+0.09ac typ street frontage=1.18ac
57/2024 LOT4
DrainageArea(ac.) 1.1800 JOB NUM3ER22106
Unit tine Minutes) 5 5 5 15
100 Year Storm Duration (hrs) 1 3 6 24
Total Predpitaticn (Plates D -4.4,E-5.2, 5.4, 5.6)(in.) 2.41 3.10 a79 5.05 from NOAA interactive website Soils Group A
MAC index II Runoff Nurrber (plate E-6.1) 32
Rate E-6.2 Pervious Area Lass Rate (Fp)(in(Ir) 0.74 (AMC II) Percentage of Inpervious Cover (A)(%) (plate E-6.3) 26.6 20% per the RCFC Hydrology Manual 1AC LOT -PLATE D 5.6 AND 0.0 1C TYPICAL STREET FRONTAGE V\kighted Average r1Ss Rate (F=Fp(1-.9A))(in./hr.) 0.56 (used for 1, 3, and 6 hour storm the 24 hour storm uses variable maximum loss rate per plate E-1.1 (3 of 6)) Low Loss Rate Percent (%) 90
Retention Basin Peroolation Rate (in/hr) 0.01 (also used for drywall percdation rate) Percolation is taken incrementally.

Basin volume is calculated using the"truncated pyramid" formula, a more conservative estimate than "averaged end areas" sometiute used program updated 4-14-22 LC
(DrywelI can be "zeroed out" by reducing numbers to less than .001, but should not entered as zeros or program chokes.) DrywelI storage indudes 40%of the 1' wide rock bed surrounding the drywall: formula (upperrPftr(diam/2)A2+(lower)*Pft)*((diam/2r2+0.41(diam/2+(grav+0.4166))"2-(diam/2+0.4166)A2)) The drywall wall thickness is assumed at 5" (0.4166) and the gravel bed width is variable "gray" Drywell is zeroed out by reducing to 0.001 since there is none.

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1 of 6

HYDROLOGY CALCULATIONS -
Using the RCFC&V\CD Short Cut Unit Hydrograph Method
Area Designations Prea 1 VERSION 2
Area=1.09ac+0.09ac typ street frontage=1.18ac
57/2024 LOT 5
DrainageArea(ac.) 1.1800 JOB NUM3ER22106
Unit tine Minutes) 5 5 5 15
100 Year Storm Duration (hrs) 1 3 6 24
Total Predpitaticn (Plates D -4.4,E-5.2, 5.4, 5.6)(in.) 2.41 3.10 a79 5.05 from NOAA interactive website Soils Group A
MAC index II Runoff Nurrber (plate E-6.1) 32
Rate E-6.2 Pervious Area Lass Rate (Fp)(in(Ir) 0.74 (AMC II) Percentage of Inpervious Cover (A)(%) (plate E-6.3) 26.6 20% per the RCFC Hydrology Manual 1AC LOT -PLATE D 5.6 AND 0.0 1C TYPICAL STREET FRONTAGE V\kighted Average r1Ss Rate (F=Fp(1-.9A))(in./hr.) 0.56 (used for 1, 3, and 6 hour storm the 24 hour storm uses variable maximum loss rate per plate E-1.1 (3 of 6)) Low Loss Rate Percent (%) 90
Retention Basin Peroolation Rate (in/hr) 0.01 (also used for drywall percdation rate) Percolation is taken incrementally.

Basin volume is calculated using the"truncated pyramid" formula, a more conservative estimate than "averaged end areas" sometiute used program updated 4-14-22 LC
(DrywelI can be "zeroed out" by reducing numbers to less than .001, but should not entered as zeros or program chokes.) DrywelI storage indudes 40%of the 1' wide rock bed surrounding the drywall: formula (upperrPftr(diam/2)A2+(lower)*Pft)*((diam/2r2+0.41(diam/2+(grav+0.4166))"2-(diam/2+0.4166)A2)) The drywall wall thickness is assumed at 5" (0.4166) and the gravel bed width is variable "gray" Drywell is zeroed out by reducing to 0.001 since there is none.

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1 of6

HYDROLOGY CALCULATIONS -
Using the RCFC&V\CD Short Cut Unit Hydrograph Method
Area Designations Area 1 VERSION 2
Area=1.16ac+0.09ac typ street frontage=1.25ar
57/2024 LOT 6
DrainageArea (ac.) 1.2500 JOB NUM3ER22106
Unit tine (rrinutes) 5 5 5 15
100 Year Storm Duration (hrs) 1 3 6 24
Total Precipitation (Plates D -4.4,E-5.2, 5.4, 5.6)(in.) 2.41 3.10 179 5.05 from NOAA interactive website Sals Coup A
MAC index II Runoff Nurrber (plate E-6.1) 32
Rate E-6.2 Pervious Area Lass Rate (Fp)(ir✓Ir) 0.74 (AMC II) Percentage of Inpervious Cover (A)(%) (plate E-6.3) 26.6 20% per the RCFC Hydrology Manual 1AC LOT -PLATE D 5.6 AND 0.09AC TYPICAL STREET FRONTAGE V'ikighted Average toss Rate (F=Fp(1-.9A))(in./hr.) 0.56 (used for 1, 3, and 6 hour storm the 24 hour storm uses variable maximum Ices rate per plate E-1.1 (3 of 6)) Low Loss Rate Percent (%) 90
Retention Basin Peroolation Rate (in/hr) 0.01 (also used for drywall percdation rate) Percolation is taken incrementally.

Basin volume is calculated using the"truncated pyramid" formula, a more conservative estimate than "averaged end areas" sometiute used program updated 4-14-22 LC
(Drywall can be "zeroed out" by reducing numbers to less than .001, but should not entered as zeros or program chokes.) Drywall storage indudes 40%of the 1' wide rock bed surrounding the drywall: formula (upperrPftr(diam/2)A2+(lower)*Pft)*((diam/2r2+0.41(diam/2+(grav+0.4166))"2-(diam/2+0.4166)A2)) The drywall wall thickness is assumed at 5" (0.4166) and the gravel bed width is variable "gray" Drywell is zeroed out by reducing to 0.001 since there is none.

Drywall design factors Upper sec. (ft.)= 0.001 Lower sec. (ft.)= 0.001 Ring diam. (ft.) = 0.001 Drywall lower max. (cf)= 0.00 Upper max.(cf)= 0.00 Gravel bed width around drywall= 0.001
DrywalI total(cf)= 0.00
Ret. Basin design (area, depth) Top = 3304 s.f. Bot. = 1123 s.f. Max. Depth (d)= 4 Max. storage= 8470.98 (d/3)*(bottorm-topF(bottorriloprO.50) Formulas vol(h/3)*(bottom+top+(bottomotop)A0.50) are =bottom+(h/d)*(top-bottom) h=(vol"3)/(bottom+top+(bottomlop)A0.5) (values must be non -zero or error occurs) Outside input from: N/A 125
1 Hour Storm in 5 minute increments Drywall Drywal Drywell Drywall Overflow Basin Basin Basin Tina Pattern Storm I nss Rate Value Effective Rcw Ray Outside Retention Period Storage Storage To Retention Period Storage Storage Overflow Overflow % Rain (inihr Max. Mn. Ran (in/hr Rate (cfs) Vd. (cf) Input (cf) Area (sf) Pero. (cf, Vd. (cf) Depth (ft) Basin (cf) Area (sf) Pero. (cf) Vol. (cf) Depth (ft Vol. (d) Rate (cfs) 0:05 17 1.0700 0.5628 N/A 0.5072 0.6393 191.78 0.00 0.00 0.00 0.00 0.00 191.78 1123.00 0.08 191.71 0.09 0.00 0.00 0:10 4.8 1.18P0 0.5628 N/A 0.8253 1.0402 312.07 0.00 0.00 0.00 0.00 0.00 312.07 1172.36 0.08 503.70 0.24 0.00 0.00 0:15 51 1.4749 0.5628 N/A 0.9121 1.1496 344.88 0.00 0.00 0.00 0.00 0.00 344.88 1252.69 0.09 848.49 0.40 0.00 0.00 0:20 4.9 1.4171 0.5628 N/A 0.8542 1.0767 323.01 0.00 0.00 0.00 0.00 0.00 323.01 1341.46 0.09 1171.40 0.55 0.00 0.00 0:25 6.6 1.9087 0.5628 N/A 1.3459 1.6964 508.91 0.00 0.00 0.00 0.00 0.00 508.91 1424.60 0.10 1680.21 0.79 0.00 0.00 0:30 7.3 21112 0.5628 N/A 1.5483 1.9515 585.46 0.00 0.00 0.00 0.00 0.00 585.46 1555.60 0.11 2265.56 1.07 0.00 0.00 0:35 54 2.4293 0.5628 N/A 1.8664 2.3525 705.75 0.00 0.00 0.00 0.00 0.00 705.75 1706.31 0.12 2971.19 1.40 0.00 0.00 0:40 9 2.6028 0.5628 N/A 2.0400 2.5712 771.36 0.00 0.00 0.00 0.00 0.00 771.36 1887.98 0.13 3742.42 1.77 0.00 0.00 0:45 12.3 15572 0.5628 N/A 2.9943 17741 1132.23 0.00 0.00 0.00 0.00 0.00 1132.23 2086.55 0.14 4874.50 2.30 0.00 0.00 0:50 17.6 5.0899 0.5628 N/A 4.5271 5.7060 1711.80 0.00 0.00 0.00 0.00 0.00 1711.80 2378.02 0.17 6586.13 3.11 0.00 0.00 0:55 16.1 4.6561 0.5628 N/A 4.0933 5.1592 1547.77 0.00 0.00 0.00 0.00 0.00 1547.77 281171 0.20 8133.71 184 0.00 0.00 1:00 4.2 1.2146 0.5628 N/A 0.6518 0.8215 246.46 0.00 0.00 0.00 0.00 0.00 246.46 3217.16 0.22 8379.95 3.96 0.00 0.00 MAX DEPTH 0 0.0000 0.5628 0.00 0.0000 0.0000 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3280.56 0.23 8379.72 196 0.00 0.00 0 0.0000 0.5628 0.00 0.0000 0.0000 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3280.50 0.23 8379.49 3.96 0.00 0.00 1:15 0 0.0000 0.5628 0.00 0.0000 0.0000 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3280.44 0.23 8379.26 196 0.00 0.00 Total volume (of) 8381.47 Total Overflow (of) 0.00
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5of6
24 1 -bur Storm in 15 minute increments Drywall Dryweil Drywall Drywell Overflow Basin Basin Basin Time Pattern Storm Loss Rate Value Effective Row Row Outside Retention Paned Storage Storage To Retention Period Storage Storage Overflow Overflow % Rain (irVhr Mex. Mn. Rain (irtrhr Rate (cfs) Vd. (cf) Irput (cf) Area (sf) Pero. (of Vol. (cf) Depth (ft) Basin (cf) Area (sf) Perc. (c) Vd. (d) Depth (ft Vol. (cf) Rate (cfs) 0:15 02 0.04
0:30 (13 0.06
0:45 0.3 0.06
1:03 (14 0.08
1:15 0.3 0.06
1:30 (13 0.06
1:45 0.3 0.06
200 (14 0.08
215 0.4 0.08
230 (14 0.08
2:45 (15 0.10
300 0.5 0.10
3:15 (15 0.10
3:30 0.5 0.10
3:45 (15 0.10
4:00 0.6 (112
4:15 (16 0.12
4:30 0.7 0.14
4:45 (17 0.14
5:00 (18 0.16
5:15 (16 0.12
5:30 0.7 (114
5:45 (18 0.16
6:00 0.8 (116
6:15 (19 0.18
6:30 (19 0.18
6:45 1 0.20
7:00 1 0.20
7:15 1 0.20
7:30 1.1 0.22
7:45 1.2 0.24
8:00 13 026
8:15 1.5 0.30
8:30 1.5 0.30
8:45 1.6 0.32
9:00 1.7 0.34
9:15 1.9 0.38
9:30 2 0.40
9:45 2.1 0.42
10:00 2.2 0.44
10:15 1.5 0.30
10:30 1.5 0.30
10:45 2 0.40
11:00 2 0.40
11:15 1.9 0.38
11:30 1.9 (138
11:45 1.7 0.34
12:00 1.8 0.36
12:15 2.5 0.51
12:30 2.6 0.53
12:45 2.8 0.57

0.99 0.04 (10040 (10051 4.58 (100 0.00 0.00 0.00 0.00 4.58 1123.00 0.23 4.35 0.00 0.00 0.00

0.98 0.05 0.0061 (10376 6.87 0.00 0.00 0.00 0.00 0.00 6.87 1124.12 0.23 10.99 0.01 0.00 (100

0.97 0.05 0.0061 0.0076 6.87 (100 (100 0.00 0.00 (100 6.87 1125.83 0.23 17.63 0.01 0.00 0.00

0.95 0.07 0.0081 (10102 9.17 0.00 (100 0.00 0.00 0.00 9.17 1127.54 0.23 26.56 0.01 0.00 (100

0.94 0.05 0.0061 0.0076 6.87 (100 (100 0.00 0.00 0.00 6.87 1129.84 (124 33.20 (102 0.00 0.00

0.93 0.05 0.0061 (10376 6.87 0.00 0.00 0.00 0.00 0.03 6.87 1131.55 (124 39.84 (102 (100 (100

0.92 0.05 0.0061 (10076 6.87 (100 0.00 0.00 0.00 0.00 6.87 1133.26 (124 46.48 (102 0.00 0.00

0.91 0.07 0.0081 (10102 9.17 0.00 (1(X) 0.00 0.00 0.03 9.17 1134.97 (124 55.40 (103 (100 (100

0.90 (107 0.0081 (10102 9.17 0.00 0.00 0.00 0.00 (100 9.17 1137.26 (124 64.33 0.03 (100 (100

0.89 0.07 0.0081 (10102 9.17 0.00 0.00 0.00 0.00 0.03 9.17 1139.56 (124 73.26 0.03 0.00 (100

0. 0.09 0.0101 (10127 11.46 0.00 0.00 0.00 0.00 0.00 11.46 1141.86 (124 84.48 (104 (100 (1(X)

0.87 0.09 (10101 0.0127 11.46 0.00 0.00 0.00 0.00 0.00 11.46 1144.75 0.24 95.70 (105 (100 (100

0.85 0.09 0.0101 (10127 11.46 0.00 0.00 0.00 0.00 0.00 11.46 1147.64 (124 106.92 (105 (100 (1(X)

0.84 0.09 (10101 0.0127 11.46 0.00 0.00 0.00 0.00 0.00 11.46 1150.53 (124 118.14 0.06 0.00 0.00

0.83 0.09 0.0101 (10127 11.46 0.00 0.00 0.00 0.00 0.00 11.46 1153.42 (124 129.35 (106 (100 0.00

0.82 0.11 (10121 0.0153 1375 0.00 0.00 0.00 0.03 0.03 1375 1156.30 0.24 142.86 (107 0.00 0.00

0.81 0.11 (10121 (10153 13.75 0.00 0.00 0.00 0.03 (100 13.75 1159.78 (124 156.37 (107 (100 0.00

0.80 0.13 (10141 0.0178 16.04 0.00 0.00 0.00 0.00 0.03 16.04 1163.26 0.24 172.16 (108 (10) 0.00

0.79 0.13 (10141 (10178 16.04 0.00 0.00 (100 0.03 (100 16.04 1167.33 (124 187.96 (109 0.00 0.00

0.78 0.15 (10162 0.0204 18.33 0.00 0.00 0.00 0.03 0.03 18.33 1171.39 (124 206.05 (110 (10) 0.00

0.77 (111 (10121 (10153 1375 0.00 0.00 0.00 0.00 (100 1375 1176.05 (125 219.55 (110 (100 0.00

0.76 0.13 (10141 (10178 16.04 0.00 0.00 0.00 0.00 0.00 16.04 1179.53 (125 235.35 (111 0.00 0.00

0.75 (115 (10162 (10204 1833 0.00 0.00 0.00 0.00 0.00 1833 1183.59 (125 253.43 (112 (100 0.00

0.74 0.15 (10162 0.0204 1833 0.00 0.00 0.00 0.00 0.00 18.33 11'x:.25 (125 271.52 (113 0.00 0.00

0.73 0.16 0.0182 (10229 20.62 0.00 0.00 0.00 0.00 0.00 20.62 1192.91 (125 291.89 (114 (100 0.00

0.72 0.16 (10182 (10229 20.62 0.0) 0.00 0.00 0.00 0.00 20.62 1198.15 0.25 312.26 (115 0.00 0.00

0.71 (118 0.0202 (10255 22.91 0.00 0.00 0.00 0.00 0.00 2291 1203.40 (125 334.93 (116 (1(X) 0.00

0.70 0.18 (10202 (10255 22.91 0.0) 0.00 0.00 0.00 0.00 2291 1209.23 0.25 357.59 (117 (1(X) 0.00

0.69 (118 0.02)2 (10255 22.91 0.00 0.00 0.00 0.00 0.00 2291 1215.07 (125 380.25 (118 (1(X) 0.00

0.68 0.20 0.0222 0.0280 25.21 0.00 0.00 0.00 0.00 0.00 25.21 1220.90 0.25 405.20 (119 0.00 0.00

0.67 0.22 (10242 0.0306 27.50 0.00 0.00 0.00 0.00 0.00 27.50 1227.33 (126 432.44 (12) (1(X) 0.00

0.66 0.24 0.0263 (10331 29.79 0.0) 0.00 0.00 0.00 0.00 29.79 1234.34 0.26 461.98 0.22 0.00 0.00

0.66 0.27 0.0303 0.0382 34.37 0.00 0.00 0.00 0.00 0.00 34.37 1241.94 (126 496.09 (123 0.00 0.00

0.65 0.27 0.0303 0.0382 34.37 0.00 0.00 0.00 0.00 0.00 34.37 1250.73 0.26 530.20 (125 0.00 0.00

0.64 0.29 0.0323 (10407 36.66 0.00 (100 0.00 0.00 0.00 36.66 1259.51 (126 566.60 (127 0.0) 0.00

0.63 0.31 0.(134,3 (10433 38.95 0.00 0.00 0.00 0.00 0.00 38.95 1268.88 0.26 605.29 0.29 0.00 0.00

0.62 0.35 0.0384 (10484 43.54 0.00 0.00 0.00 0.00 0.00 43.54 1278.84 (127 648.56 (131 0.00 0.00

0.61 0.36 (10404 (10509 45.83 0.00 0.00 0.00 0.00 0.00 45.83 1289.98 0.27 694.12 0.33 0.00 0.00

0.60 0.38 0.0424 (10535 48.12 0.00 0.00 0.00 0.00 0.00 48.12 1301.71 (127 741.97 (135 (1(X) (100

0.59 0.40 (10444 0.0560 50.41 0.00 0.00 0.00 0.00 0.00 50.41 1314.03 (127 792.11 0.37 0.00 0.00

0.58 0.27 0.0303 (10382 34.37 (100 0.00 0.00 0.00 0.00 34.37 1326.94 (128 826.20 (139 0.00 0.00

0.58 0.27 0.0303 (10382 34.37 0.00 (100 0.00 0.00 0.00 34.37 1335.72 (128 860.30 (141 (200 0.00 (157 0.36 0.0404 0.0509 45.83 0.00 0.00 0.00 0.00 (100 45.83 1344.50 (128 905.84 (143 0.00 0.00

0.56 0.36 (10404 0.0509 45.83 0.00 0.00 0.00 0.00 0.00 45.83 1356.23 (128 951.39 (145 0.00 0.00 (155 0.35 0.0384 0.0484 43.54 0.00 (1(X) (100 0.00 0.00 43.54 1367.95 (128 994.64 (147 0.00 0.00

0.54 0.35 0.0384 0.0484 43.54 0.00 0.00 0.00 0.00 0.00 43.54 1379.09 (129 1037.89 0.49 (200 0.00 (153 0.31 0.0343 0.0433 38.95 (100 (1(X) 0.00 0.00 (100 38.95 1390.22 (129 1076.56 0.51 (100 0.00

0.53 0.33 0.0364 0.0458 41.25 0.00 0.00 0.00 (1(X) 0.00 41.25 1400.18 (129 1117.51 0.53 (200 0.00 (152 0.45 0.0505 0.0637 57.29 0.00 0.00 0.00 0.00 0.00 57.29 1410.72 0.29 1174.50 0.55 0.00 0.00

0.51 0.47 (10525 0.0662 59.58 0.00 0.00 0.00 0.00 0.00 59.58 1425.40 0.30 1233.78 0.58 (100 0.00

0.50 NYA 0.0622 (10784 70.59 0.00 0.00 0.00 0.00 0.00 70.59 1440.66 0.30 1304.08 0.62 0.00 0.00 1263

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1 of6

HYDROLOGY CALCULATIONS -
Using the RCFC&V\CD Short Cut Unit Hydrograph Method
Area Designations Area 1 VERSION 2
Area=1.16ac+0.09ac typ street frontage=1.25ar
57/2024 LOT 7
DrainageArea (ac.) 1.2500 JOB NUM3ER22106
Unit tine (rrinutes) 5 5 5 15
100 Year Storm Duration (hrs) 1 3 6 24
Total Precipitation (Plates D -4.4,E-5.2, 5.4, 5.6)(in.) 2.41 3.10 179 5.05 frcm NOAA interactive website Sals Coup A
MAC index II Runoff Nurrber (plate E-6.1) 32
Rate E-6.2 Pervious Area Lass Rate (Fp)(ir✓Ir) 0.74 (AMC II) Percentage of Inpervious Cover (A)(%) (plate E-6.3) 26.6 20% per the RCFC Hydrology Manual 1AC LOT -PLATE D 5.6 AND 0.09AC TYPICAL STREET FRONTAGE V'ikighted Average r1Ss Rate (F=Fp(1-.9A))(in./hr.) 0.56 (used for 1, 3, and 6 hour storm the 24 hour storm uses variable maximum Ices rate per plate E-1.1 (3 of 6)) Low Loss Rate Percent (%) 90
Retention Basin Peroolation Rate (in/hr) 0.01 (also used for drywall percdation rate) Percolation is taken incrementally.

Drywall design factors Upper sec. (ft.)= 0.001 Lower sec. (ft.)= 0.001 Ring diam. (ft.) = 0.001 Drywall lower max. (cf)= 0.00 Upper max.(cf)= 0.00 Gravel bed width around drywall= 0.001
DrywalI total(cf)= 0.00
Ret. Basin design (area, depth) Top = 3304 s.f. Bot. = 1123 s.f. Max. Depth (d)= 4 Max. storage= 8470.98 (d/3)*(bottomi-topF(bottorriloprO.50) Formulas vol(h/3)*(bottom+top+(bottomotop)A0.50) are =bottom+(h/d)*(top-bottom) h=(vol"3)/(bottom+top+(bottomlop)A0.5) (values must be non -zero or error occurs) Outside input from: N/A 125
1 Hour Storm in 5 minute increments Drywall Drywal Drywell Drywall Overflow Basin Basin Basin Tina Pattern Storm I nss Rate Value Effective Rcw Ray Outside Retention Period Storage Storage To Retention Period Storage Storage Overflow Overflow % Rain (inihr Max. Mn. Ran (in/hr Rate (cfs) Vd. (cf) Input (cf) Area (sf) Pero. (cf, Vd. (cf) Depth (ft) Basin (cf) Area (sf) Pero. (cf) Vol. (cf) Depth (ft Vol. (d) Rate (cfs) 0:05 17 1.0700 0.5628 N/A 0.5072 0.6393 191.78 0.00 0.00 0.00 0.00 0.00 191.78 1123.00 0.08 191.71 0.09 0.00 0.00 0:10 4.8 1.18P0 0.5628 N/A 0.8253 1.0402 312.07 0.00 0.00 0.00 0.00 0.00 312.07 1172.36 0.08 503.70 0.24 0.00 0.00 0:15 51 1.4749 0.5628 N/A 0.9121 1.1496 344.88 0.00 0.00 0.00 0.00 0.00 344.88 1252.69 0.09 848.49 0.40 0.00 0.00 0:20 4.9 1.4171 0.5628 N/A 0.8542 1.0767 323.01 0.00 0.00 0.00 0.00 0.00 323.01 1341.46 0.09 1171.40 0.55 0.00 0.00 0:25 6.6 1.9087 0.5628 N/A 1.3459 1.6964 508.91 0.00 0.00 0.00 0.00 0.00 508.91 1424.60 0.10 1680.21 0.79 0.00 0.00 0:30 7.3 21112 0.5628 N/A 1.5483 1.9515 585.46 0.00 0.00 0.00 0.00 0.00 585.46 1555.60 0.11 2265.56 1.07 0.00 0.00 0:35 54 2.4293 0.5628 N/A 1.8664 2.3525 705.75 0.00 0.00 0.00 0.00 0.00 705.75 1706.31 0.12 2971.19 1.40 0.00 0.00 0:40 9 2.6028 0.5628 N/A 2.0400 2.5712 771.36 0.00 0.00 0.00 0.00 0.00 771.36 1887.98 0.13 3742.42 1.77 0.00 0.00 0:45 12.3 15572 0.5628 N/A 2.9943 17741 1132.23 0.00 0.00 0.00 0.00 0.00 1132.23 2086.55 0.14 4874.50 2.30 0.00 0.00 0:50 17.6 5.0899 0.5628 N/A 4.5271 5.7060 1711.80 0.00 0.00 0.00 0.00 0.00 1711.80 2378.02 0.17 6586.13 3.11 0.00 0.00 0:55 16.1 4.6561 0.5628 N/A 4.0933 5.1592 1547.77 0.00 0.00 0.00 0.00 0.00 1547.77 281171 0.20 8133.71 184 0.00 0.00 1:00 4.2 1.2146 0.5628 N/A 0.6518 0.8215 246.46 0.00 0.00 0.00 0.00 0.00 246.46 3217.16 0.22 8379.95 3.96 0.00 0.00 MAX DEPTH 0 0.0000 0.5628 0.00 0.0000 0.0000 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3280.56 0.23 8379.72 196 0.00 0.00 0 0.0000 0.5628 0.00 0.0000 0.0000 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3280.50 0.23 8379.49 3.96 0.00 0.00 1:15 0 0.0000 0.5628 0.00 0.0000 0.0000 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3280.44 0.23 8379.26 196 0.00 0.00 Total volume (of) 8381.47 Total Overflow (of) 0.00
1265

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