Twentynine Palms City Council
July 22, 2025

10 Figure 5. Previous cultural resources studies in the vicinity of the project area, listed by SCCIC file number. Locations of historical/archaeological sites are not shown as a protective measure. . ,, ,}',?, -:./
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11 HISTORICAL RESEARCH
Based on the historical sources consulted for this study, the project area appears to be relatively low in sensitivity for cultural resources from the historic period. Historical maps and aerial/satellite photographs suggest that the project area remained unsettled and undeveloped throughout the historic period (Figs. 6; 7; NETR Online 1970). By the 1950s, Twentynine Palms Highway had been built adjacent to the northern project boundary, and several sparsely populated residential tracts had appeared in the surrounding area, including one immediately to the west of the project location (Fig. 7). None of these nearby developments, however, appeared to have had an impact on land use within the project area itself.

In 1970, a web of unpaved dirt roads was noted in the northeastern portion of the project area, the first human-made features to appear within the project boundaries (NETR Online 1970; Fig. 3).

Despite the presence of the roads, no further development had occurred on the property by that time, nor has any taken place since then (NETR Online 1970-202; Google Earth 1994-2023). To this day, the entire project area retains much of its altered natural landscape (Google Earth 2023).

Figure 6. The project area and vicinity in 1855-1913.
(Source: GLO 1856; 1914)
Figure 7. The project area and vicinity in 1937-1952.
(Source: USGS 1955)

FIELD SURVEY
During the field survey, 19 previously undocumented cultural resources were recorded within the project boundaries and designated temporarily as 4064-1H through 4064-19, pending assignment of permanent identification numbers in the California Historical Resources Inventory. Outside but adjacent to the northern project boundary, Twentynine Palms Highway was previously recorded as a 0 . Project
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12 part of Site 36-010525, as noted above. As a working component of the modern transportation infrastructure, the highway today does not demonstrate any distinctively historical character as its current appearance reflects the results of continuous upgrading and maintenance since the historic era (Fig. 8). As the proposed project has no potential to alter the condition of the highway substantially, Site 36-010525 requires no further consideration during this study.

Scattered widely across the property, the 19 newly identified cultural resources within the project boundaries include prehistoric (i.e., Native American) milling features and lithic artifacts as well as historic-period refuse items, and they were recorded as 5 archaeological sites and 14 isolates (i.e., localities with fewer than three artifacts). These resources are discussed further below, and additional information is provided in the standard record forms attached to this report in Appendix 3. • Site 4064-1H: Historic-period refuse scatter with five sanitary cans, three flat-top beverage cans, three corrugated sanitary cans, one bimetal can, and can fragments (Fig. 9). • Site 4064-2H: Historic-period refuse scatter with colorless mason jar finish, body fragment of colorless square glass bottle, Dr. Pepper ACL body fragments bearing the clock logo, fragments of amber glass, a stubby bottle finish and body fragment, amber bottle body neck, and base fragments with a keystone 1961 maker’s mark, amber beer bottle base with a circle-B maker’s mark and a date of 1964, a stippled amber body fragment, and a green 7-Up body fragment (Fig. 10).
• Isolate 4064-3H: Crushed circular water can with handle, crushed, rusted, and decomposing within berm along dirt road/drainage (Fig.11).
• Isolate 4064-4H: Colorless bottle base with a 1954 date mark and “Wholesome (World Famous) Beverages” and textured cross lines (Fig. 12).
• Isolate 4065-5: Smokey quartz unifacially worked tool with chipping (5 chips) along worked edge. Tool measures 4.5x2.2x1.5 cm (Fig. 13).
• Isolate 4064-6: Quartzite secondary flake with a tannish grey cortex (approximately 15% remaining), measuring 8.6x8.2x2.8 cm (Fig. 14).
• Site 4064-7: Quartzite interior flake (0% cortex) with a clear platform and bulb of percussion present. Distal end has significant quartz inclusions, 3.5x3.5x0.7 cm. Quartzite conglomerate (granite) milling slick, partially buried and immobile, measuring 44x20 cm with an exposed height of 10 cm. The utilized working surface is approximately 27x8 cm. Crystals on the working surface are crushed with the ridges rounded. Creosote and yucca are in the immediate vicinity of the slick (Fig. 15).
• Site 4064-8H: Two colorless bottle fragments, “No Deposit” on shoulder fragment, scalloping, 1974 date mark and a circle-B maker’s mark, colorless bottle fragment with crescents on ridge of base, “No Deposit” on shoulder fragment and an Owens-Illinois maker’s mark. 3 amber OwensIllinois Budweiser bottles, highly fragmented, 2 amber Budweiser bottles, highly fragmented, 1 amber Budweiser bottle, highly fragmented, 4 amber Budweiser bottles, highly fragmented, 2 amber highly fragmented Budweiser bottles. All Budweiser bottles bear the date mark for 1974.

Rectangular can of “Sucrets” (maybe as late as 1980s?) measuring 3-3/4”x2-1/2”x5/8” (Fig. 16). • Isolate 4064-9H: 1948 1-quart liquor bottle with rusted cap: “Federal law forbids sale or re-use of this bottle” (Fig. 17).
• Isolate 4064-10: Quartzite interior flake with 2 smaller flake scars indicating microflaking after initial flake removal. No cortex remaining, desert patina on ventral face. Measures 6.4x5.8x1.6 cm (Fig. 18).

13 Figure 8. Site 36-010525, State Route 62 (Twentynine Palms Highway) along the northern edge of the project area.

Figure 9. Site 4064-1H, mid-20th century can scatter.

14 Figure 10. Site 4064-2H, mid-20th century refuse scatter.

Figure 11. Isolate 4064-3H, crushed mid-20th century water can.

15 Figure 12. Isolate 4064-4H, 1954 bottle fragments.

Figure 13. Isolate 4064-5, quartz cutting tool.

16 Figure 14. Isolate 4064-6, quartzite flake.

Figure 15. Site 4064-7, metate with lithic flake.

17 Figure 16. Site 4064-8H, refuse scatter with 1970s bottle fragments.

Figure 17. Isolate 4064-9H, 1948 liquor bottle.

18 Figure 18. Isolate 4064-10, quartzite flake.
• Isolate 4064-11: Quartzite flake tool, “scraper.” No cortex remains and step fractures are readily apparent. Proximal end displays unifacial chipping along lateral edge. Measures 6.5x5.0x1.6 cm (Fig. 19).
• Isolate 4064-12H: Colorless screw top bottle, L in circle maker’s mark, 1977 date code but appears much older (Fig. 20).
• Isolate 4064-13H: Hole-in-top can. This isolate consists of a solder dot can with a center solder seal and soldered seams, opened on the bottom with a single church key opening, early 20th century (Fig. 21).
• Isolate 4064-14H: Hole-in-top can. This isolate consists of a solder dot can with a center solder seal and soldered seams, opened on the bottom with a single church key opening (Fig. 22). • Isolate 4064-15H: Hole-in-top can. This isolate consists of a solder dot can with a center solder seal and soldered seams, opened on the top with a single church key opening (Fig. 23). • Isolate 4065-16: Milky quartz flake, measures 2.9x1.7x0.8 cm with a clear bulb of percussion and battering apparent on platform (Fig. 24).
• Isolate 4064-17: Quartzite interior flake, 5 flake scars on dorsal face and battering on proximal end, measuring 2.6x2.2x0.6 cm (Fig. 25).
• Site 4064-18: Quartzite milling feature measuring 35.5x21.8 cm, extending 5 cm out of the ground, and bearing an exceptionally worn slick with heavy polish. The working surface measures approximately 19.0x13.5 cm. The rock is buried and immobile (Fig. 26). • Isolate 4064-19: Quartzite secondary flake retaining 15% cortex with large quartz inclusions.

Platform and bulb of percussion are evident with the stone bearing grey and white banding, measuring 2.4x3.2x0.5 cm (Fig. 27).

19 Figure 19. Isolate 4064-11, quartzite scraper or cutting tool.

Figure 20. Isolate 4064-12H, glass bottle, date unknown. Figure 21. Isolate 4064-13H, solder drop can, early 20th century.

20 Figure 22. Isolate 4064-14H, solder drop can, early 20th century.

Figure 23. Isolate 4064-15H, solder drop can, early 20th century.

Figure 24. Isolate 4064-16, milky quartz flake.

21 Figure 25. Isolate 4064-17, quartzite flake.

Figure 26. Site 4064-18, prehistoric milling feature.

22 Figure 27. Isolate 4064-19, quartzite flake.

MANAGEMENT CONSIDERATIONS

APPLICABLE STATUTORY/REGULATORY FRAMEWORK
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 defined by PRC §5020.1(q), “‘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 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:

23 (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. (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)).

CONCLUSION AND RECOMMENDATIONS
In summary of the research results presented in this report, a total of 19 cultural resources, including 5 archaeological sites and 14 isolates, were discovered and recorded within the project area during this study and designated temporarily as 4064-1H through 4064-19. Among these are 2 prehistoric sites, 3 historic-period sites, 7 prehistoric isolates, and 7 historic-period isolates. According to guidelines set forth by the California Office of Historic Preservation, isolates with fewer than three artifacts, by definition, do not qualify as archaeological sites due to the lack of contextual integrity.

As such, the 14 isolates found in the project area are not considered potential “historical resources” and require no further consideration in the CEQA compliance process.

All three historic-period sites in the project area, 4064-1H, 4064-2H, and 4064-8H, consist of mid20th century refuse scatters, the most common type of cultural remains from the historic era to be found in the southern California desert region. Such minor refuse deposits from the late historic period and of unclear historical background generally lack any identifiable association, let alone a close association, with significant persons or events in history. Without an exceptional quantity or quality of artifacts, they hold little promise for any new or important archaeological data. Therefore, Sites 4064-1H, 4064-2H, and 4064-8H do not appear eligible for listing in the California Register of Historical Resources, based on the criteria listed above, and do not meet the definition of “historical resources” under CEQA provisions.

The two prehistoric sites in the project area, 4064-7 and 4064-18, consist of milling features, one of them with an associated lithic flake. Isolated milling features with shallow slicks like those recorded at Sites 4064-7 and 4064-18 are also a common occurrence in southern California. They are interpreted as food-processing sites resulting from occasional use by Native people on resourcegathering excursions and do not represent the sites of long-term habitation. Because the presence or absence of additional cultural materials in buried deposits in the vicinity of the milling features cannot be ascertained on the basis of the surface survey alone, the data potential of these two sites— and thereby their eligibility for listing in the California Register—cannot be determined without further archaeological investigation, including subsurface testing. However, according to the current project plans, each of these sites lies several hundred feet from the nearest development activities proposed on the property (see location map in App. 3). As a result, the project is not anticipated to impact the current condition of Sites 4064-7 and 4064-18.

In order to ensure the proper protection of Sites 4064-7 and 4064-18 and prevent inadvertent damages, CRM TECH recommends that both of these sites be placed in clearly demarcated Environmentally Sensitive Areas during project construction. In addition to the presence of Sites

24 4064-7 and 4064-18, the number and multiplicity of isolated Native American flaked-stone artifacts recorded during this study also serve to underscore the overall sensitivity of the project location for buried cultural remains from the prehistoric era. For the timely identification and, if necessary, protection of such remains during construction, CRM TECH further recommends that an archaeological monitoring program be designed and implemented during earth-moving operations associated with the project. The monitoring program should be coordinated with the Twentynine Palms Band of Mission Indians and the Morongo Band of Mission Indians, who may wish to participate. Under these conditions, the proposed project may be cleared to proceed in compliance with CEQA provisions on cultural resources.

REFERENCES
Bean, Lowell John, and Charles R. Smith
1978 Serrano. In Robert F. Heizer (ed.): Handbook of North American Indians, Vol. 8:

California; pp. 570-574. Smithsonian Institution, Washington, D.C.

Beck, Warren A., and Ynez D. Haase
1974 Historical Atlas of California. University of Oklahoma Press, Norman, Oklahoma.

DesertUSA
n.d. Twentynine Palms, California: History. http://www.desertusa.com/Cities/ca/ 29palms.html.

Gallegos, Dennis, John Cook, Emma Lou Davis, Gary Lowe, Frank Norris, and Jay Thesken 1980 Cultural Resources Inventory of the Central Mojave and Colorado Desert Regions, California. U.S. Bureau of Land Management, California Desert District, Riverside.

GLO (General Land Office, U.S. Department of the Interior) 1856 Plat Map: Township No. 1 North Range No. 8 East, SBBM; surveyed in 1855-1856. 1914 Plat Map: Township No. 1 South Range No. 8 East, SBBM; surveyed in 1855-1913.

Google Earth
1994-2023 Aerial photographs of the project vicinity; taken in 1994, 1996, 2002, 2005-2007, 2009, 2011-2013, 2015-2019, 2021, 2022, and 2023. Available through the Google Earth software.

Hall, M.C.
2000 Archaeological Survey of 2472 Acres in Adjacent Portions of Lava, Lead Mountain, and Cleghorn Pass Training Areas, Marine Corps Air Ground Combat Center, Twentynine Palms, California (Volume I). Report prepared by the Archaeological Research Unit, University of California, Riverside, for the United States Marine Corps Natural Resources and Environmental Affairs Division.

Kelly, Isabel T., and Catherine S. Fowler
1986 Southern Paiute. In Warren L. D’Azevedo (ed.): Handbook of North American Indians, Vol. 11: Great Basin; pp. 368-397. Smithsonian Institution, Washington, D.C.

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

Washington, D.C.

Laird, Carobeth
1976 The Chemehuevis. Malki Museum Press, Banning, California.

25 NETR (Nationwide Environmental Title Research) Online 1970-2020 Aerial photographs of the project vicinity; taken in 1970, 1983, 1994, 1996, 2002, 2005, 2009, 2010, 2012, 2014, 2016, 2018, and 2020. http://www.historicaerials.com.

NPS (National Park Service, U.S. Department of the Interior) n.d. Joshua Tree National Park, California: Oasis of Mara. https://www.nps.gov/jotr/learn/ historyculture/mara.htm.

Purcell, D.E.
2000 California Historical Resources Inventory record forms, Site 36-010525 (CA-SBR10525H). On file, South Central Coastal Information Center, California State University, Fullerton.

Strong, William Duncan
1929 Aboriginal Society in Southern California. University of California Publications in American Archaeology and Ethnology 26. Reprinted by Malki Museum Press, Banning, California, 1972.

USGS (United States Geological Survey, U.S. Department of the Interior) 1955 Map: Twentynine Palms, Calif. (15', 1:62,500); aerial photographs taken in 1937 and 1952.
1969a Map: Needles, California; Arizona (120’x60’, 1:250,000); 1956 edition revised. 1969b Map: San Bernardino, Calif. (120’x60’, 1:250,000); 1958 edition revised. 1994a Map: Indian Cove, Calif. (7.5’, 1:24,000); photoinspected in 1994. 1994b Map: Sunfair, Calif. (7.5’, 1:24,000); photoinspected in 1994.

Warren, Claude N.
1984 The Desert Region. In Michael J. Moratto (ed.): California Archaeology; pp. 339-430.

Academic Press, Orlando, Florida.

Warren, Claude N., and Robert H. Crabtree
1986 Prehistory of the Southwestern Area. In Warren L. D’Azevedo (ed.): Handbook of North American Indians, Vol. 11: Great Basin; pp. 183-193. Smithsonian Institution, Washington, D.C.

Warren, Elizabeth von Till, Robert H. Crabtree, Claude N. Warren, Martha Knack, and Richard McCarty
1981 A Cultural Resources Overview of the Colorado Desert Planning Units. U.S. Bureau of Land Management, California Desert District, Riverside.

26 APPENDIX 1:

PERSONNEL QUALIFICATIONS

PRINCIPAL INVESTIGATOR/HISTORIAN
Bai “Tom” Tang, M.A.

Education
1988-1993 Graduate Program in Public History/Historic Preservation, University of California, Riverside.
1987 M.A., American History, Yale University, New Haven, Connecticut. 1982 B.A., History, Northwestern University, Xi’an, China. 2000 “Introduction to Section 106 Review,” presented by the Advisory Council on Historic Preservation and the University of Nevada, Reno.
1994 “Assessing the Significance of Historic Archaeological Sites,” presented by the Historic Preservation Program, University of Nevada, Reno.

Professional Experience
2002- Principal Investigator, CRM TECH, Riverside/Colton, California. 1993-2002 Project Historian/Architectural Historian, CRM TECH, Riverside, California. 1993-1997 Project Historian, Greenwood and Associates, Pacific Palisades, California. 1991-1993 Project Historian, Archaeological Research Unit, University of California, Riverside. 1990 Intern Researcher, California State Office of Historic Preservation, Sacramento. 1990-1992 Teaching Assistant, History of Modern World, University of California, Riverside. 1988-1993 Research Assistant, American Social History, University of California, Riverside. 1985-1988 Research Assistant, Modern Chinese History, Yale University. 1985-1986 Teaching Assistant, Modern Chinese History, Yale University. 1982-1985 Lecturer, History, Xi’an Foreign Languages Institute, Xi’an, China.

Cultural Resources Management Reports
Preliminary Analyses and Recommendations Regarding California’s Cultural Resources Inventory System (with Special Reference to Condition 14 of NPS 1990 Program Review Report). California State Office of Historic Preservation working paper, Sacramento, September 1990.

Numerous cultural resources management reports with the Archaeological Research Unit, Greenwood and Associates, and CRM TECH, since October 1991.

27 PRINCIPAL INVESTIGATOR/ARCHAEOLOGIST
Michael Hogan, Ph.D., RPA (Registered Professional Archaeologist) Education
1991 Ph.D., Anthropology, University of California, Riverside. 1981 B.S., Anthropology, University of California, Riverside; with honors. 1980-1981 Education Abroad Program, Lima, Peru.
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.

Professional Experience
2002- Principal Investigator, CRM TECH, Riverside/Colton, California. 1999-2002 Project Archaeologist/Field Director, CRM TECH, Riverside, California. 1996-1998 Project Director and Ethnographer, Statistical Research, Inc., Redlands, California. 1992-1998 Assistant Research Anthropologist, University of California, Riverside. 1992-1995 Project Director, Archaeological Research Unit, U.C. Riverside. 1993-1994 Adjunct Professor, Riverside Community College, Mt. San Jacinto College, U.C.

Riverside, Chapman University, and San Bernardino Valley College. 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.

28 PROJECT ARCHAEOLOGIST/REPORT WRITER
Frank J. Raslich, M.A.

Education
2016- Ph.D. candidate, Michigan State University, East Lansing. 2010 M.A., Anthropology, Michigan State University, East Lansing. 2005 B.A., Anthropology, University of Michigan, Flint. 2019 Grant and Research Proposal Writing for Archaeologists; Society for American Archaeology online seminar.
2014 Bruker Industries Tracer S1800 pXRF Training; presented by Dr. Bruce Kaiser, Bruker Scientific.

Professional Experience
2022- Project Archaeologist/Report Writer, CRM TECH, Colton, California. 2022 Archaeological Monitor, Agua Caliente Band of Cahuilla Indians, Palm Springs, California.
2014-2022 Board of Directors, Ziibiwing Center of Anishinabe Culture and Lifeways, Saginaw Chippewa Indian Tribe of Michigan.
2008-2021 Archaeological Consultant, Saginaw Chippewa Indian Tribe of Michigan. 2019 Archaeologist, Sault Tribe of Chippewa Indians and Little Traverse Bay Band of Odawa Indians.
2016-2018 Adjunct Lecturer, Michigan State University, East Lansing. 2017-2018 Adjunct Lecturer, University of Michigan, Flint. 2009-2017 Teaching Assistant, Michigan State University, East Lansing. 2008-2014 Research Assistant, Intellectual Property Issues in Cultural Heritage, Simon Fraser University, British Columbia, Canada.
2010-2013 Research Assistant, Michigan State University, East Lansing. 2009-2011 Archaeologist/Crew Chief, Saginaw Chippewa Indian Tribe of Michigan.

Publications
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).

29 PROJECT ARCHAEOLOGIST/FIELD DIRECTOR
Daniel Ballester, M.S., RPA (Registered Professional Archaeologist) Education
2013 M.S., Geographic Information System (GIS), University of Redlands, California. 1998 B.A., Anthropology, California State University, San Bernardino. 1997 Archaeological Field School, University of Las Vegas and University of California, Riverside.
1994 University of Puerto Rico, Rio Piedras, Puerto Rico.

Professional Experience
2002- Field Director/GIS Specialist, CRM TECH, Riverside/Colton, California. 2011-2012 GIS Specialist for Caltrans District 8 Project, Garcia and Associates, San Anselmo, California.
2009-2010 Field Crew Chief, Garcia and Associates, San Anselmo, California. 2009-2010 Field Crew, ECorp, Redlands.
1999-2002 Project Archaeologist, CRM TECH, Riverside, California. 1998-1999 Field Crew, K.E.A. Environmental, San Diego, California. 1998 Field Crew, A.S.M. Affiliates, Encinitas, California. 1998 Field Crew, Archaeological Research Unit, University of California, Riverside.

PROJECT ARCHAEOLOGIST
Hunter C. O’Donnell, B.A.

Education
2016- M.A. Program, Applied Archaeology, California State University, San Bernardino. 2015 B.A. (cum laude), Anthropology, California State University, San Bernardino. 2012 A.A., Social and Behavioral Sciences, Mt. San Antonio College, Walnut, California. 2011 A.A., Natural Sciences and Mathematics, Mt. San Antonio College, Walnut, California.

Professional Experience
2022- Field Crew Chief, CRM TECH, Colton, California.
2017- Project Archaeologist, CRM TECH, Colton, California. 2016-2018 Graduate Research Assistant, Applied Archaeology, California State University, San Bernardino.
2016-2017 Cultural Intern, Cultural Department, Pechanga Band of Luiseño Indians, Temecula, California.
2015 Archaeological Intern, U.S. Bureau of Land Management, Barstow, California. 2015 Peer Research Consultant: African Archaeology, California State University, San Bernardino.

30 PROJECT ARCHAEOLOGIST
Michael D. Richards, M.A., RPA (Registered Professional 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.

Memberships
Society for American Archaeology; Society for California Archaeology; Archaeological Institute of America; Conejo Open Space Trails Advisory Committee; Conejo Valley Historical Society.

PROJECT ARCHAEOLOGIST/NATIVE AMERICAN LIAISON
Nina Gallardo, B.A.

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.

31 APPENDIX 2

NATIVE AMERICAN SACRED LANDS FILE

SEARCH RESULTS

32 P.ICAfv.-<;,
ff ~-~~i z • .
°' 0->'I) •

CHAIRPERSON
Reginald Pagaling
Chumash

VICE-CHAJRPERSON
Bully McQulllen
Yo kayo Porno, Yuki,
Nomlaki

SECRETARY
Sara Dutschke
Miwok

P ARLIAMENTARIAJN
Wayne Nelson
LuiseFio

CO/WAISSIONER
Isaac Bojorquez
Ohlone-Costanoan

COIWAISSIONER
Stanley Rodriguez
Kumeyaay

COIWAISSIONER
Laurena Bolden
Serrano

COIWAISSIONER
Reid Milanovich
Cahuilla

COIWAISSIONER
Vacant

EXECUTIVE SECRETARY
Raymond C.

Hitchcock
Miwok, Nisenan

NAHC HEADQUARTERS
1550 Harbor Boulevard
Suite 100
West Sacramento,
Ca!fomia 95691
(916) 3 73-371 0
[email protected]
NAHC.ca.gov
STATE OF CAUFORNIA Gavin Newsom Governor

NATIVE AMERICAN HERITAGE COMMISSION
November 21, 2023
Nina Gallardo

CRM TECH
Via Email to: [email protected]
Re: Proposed 29 Palms Yonder Hospitality - Glamping Resort on Assessor's Parcel Number 0614- 121-15 (CRM TECH No. 4064), San Bernardino County
Dear Ms. Gallardo:

A record search of the Native American Heritage Commission (NAHC) Sacred Lands File (SLF) was 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 localing 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. If 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: [email protected].

Sincerely,
Cameron Vela
Cultural Resources Analyst
Attachment

33 Native American Heritage Commission
Native American Contact List
San Bernardino County
11/21/2023
Tribe Name Fed (F)
Non-Fed (N)
Contact Person Contact Address Phone # Fax # Email Address Cultural Affiliation
Counties
Agua Caliente Band of
Cahuilla Indians
F Patricia Garcia, Director of
Historic Preservation
5401 Dinah Shore Drive
Palm Springs, CA, 92264
(760) 699-
6907
(760) 699-
6919
[email protected] Cahuilla Imperial,Riverside,San Bernardino,San Diego
Augustine Band of Cahuilla
Mission Indians
F Amanda Vance,
Chairperson
84-001 Avenue 54
Coachella, CA, 92236
(760) 398-
4722
(760) 369-
7161
[email protected] Cahuilla Imperial,Riverside,San Bernardino,San Diego
Cabazon Band of Mission
Indians
F Doug Welmas, Chairperson 84-245 Indio Springs
Parkway
Indio, CA, 92203
(760) 342-
2593
(760) 347-
7880
[email protected] Cahuilla Imperial,Riverside,San Bernardino,San Diego
Cahuilla Band of Indians F BobbyRay Esaprza, Cultural
Director
52701 CA Highway 371
Anza, CA, 92539
(951) 763-
5549
[email protected] Cahuilla Imperial,Riverside,San Bernardino,San Diego
Cahuilla Band of Indians F Anthony Madrigal, Tribal
Historic Preservation Officer
52701 CA Highway 371
Anza, CA, 92539
(951) 763-
5549
[email protected] Cahuilla Imperial,Riverside,San Bernardino,San Diego
Cahuilla Band of Indians F Daniel Salgado, Chairperson 52701 CA Highway 371 Anza, CA, 92539
(951) 972-
2568
(951) 763-
2808
[email protected] Cahuilla Imperial,Riverside,San Bernardino,San Diego
Los Coyotes Band of
Cahuilla and Cupeño 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
Indians
F Robert Martin, Chairperson 12700 Pumarra Road
Banning, CA, 92220
(951) 755-
5110
(951) 755-
5177
[email protected] Cahuilla
Serrano
Imperial,Los Angeles,Riverside,San
Bernardino,San Diego
Morongo Band of Mission
Indians
F Ann Brierty, THPO 12700 Pumarra Road
Banning, CA, 92220
(951) 755-
5259
(951) 572-
6004
[email protected] Cahuilla
Serrano
Imperial,Los Angeles,Riverside,San
Bernardino,San Diego
Quechan Tribe of the Fort
Yuma Reservation
F Jill McCormick, Historic
Preservation Officer
P.O. Box 1899
Yuma, AZ, 85366
(928) 261-
0254
[email protected] Quechan Imperial,Kern,Los Angeles,Riverside,San Bernardino,San Diego
Quechan Tribe of the Fort
Yuma Reservation
F Jordan Joaquin, President,
Quechan Tribal Council
P.O.Box 1899
Yuma, AZ, 85366
(760) 919-
3600
[email protected] Quechan Imperial,Kern,Los Angeles,Riverside,San Bernardino,San Diego
Quechan Tribe of the Fort
Yuma Reservation
F Manfred Scott, Acting
Chairman - Kw'ts'an Cultural
Committee
P.O. Box 1899
Yuma, AZ, 85366
(928) 210-
8739
[email protected] Quechan Imperial,Kern,Los Angeles,Riverside,San Bernardino,San Diego
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
Ramona Band of Cahuilla F John Gomez, Environmental
Coordinator
P. O. Box 391670
Anza, CA, 92539
(951) 763-
4105
(951) 763-
4325
[email protected] Cahuilla Imperial,Riverside,San Bernardino,San Diego
San Manuel Band of Mission
Indians
F Alexandra McCleary,
Cultural Lands Manager
26569 Community Center
Drive
Highland, CA, 92346
(909) 633-
0054
alexandra.mccleary@sanmanuelnsn.govSerrano Kern,Los Angeles,Riverside,San Bernardino
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
Serrano Nation of Mission
Indians
N Mark Cochrane, CoChairpersonP. O. Box 343
Patton, CA, 92369
(909) 578-
2598
[email protected] Serrano Los Angeles,Riverside,San Bernardino Serrano Nation of Mission
Indians
N Wayne Walker, CoChairpersonP. O. Box 343
Patton, CA, 92369
(253) 370-
0167
[email protected] Serrano Los Angeles,Riverside,San Bernardino 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 Alesia Reed, Cultural
Committee Chairwoman
P.O. Box 1160
Thermal, CA, 92274
(760) 397-
0300
[email protected] Cahuilla Imperial,Riverside,San Bernardino,San Diego
+
+
+
+- +
+- +

34 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 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 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
Twenty-Nine Palms Band of
Mission Indians
F Nicolas Garza, Cultural
Resources Specialist
46-200 Harrison Place
Coachella, CA, 92236
(760) 863-
2486
[email protected] Chemehuevi Imperial,Inyo,Riverside,San Bernardino Twenty-Nine Palms Band of
Mission Indians
F Sarah O'Brien, Tribal
Archivist
46-200 Harrison Place
Coachella, CA, 92236
(760) 863-
2460
[email protected] Chemehuevi Imperial,Inyo,Riverside,San Bernardino Twenty-Nine Palms Band of
Mission Indians
F Christopher Nicosia, Cultural
Resources Manager/THPO
Manager
46-200 Harrison Place
Coachella, CA, 92236
(760) 863-
3972
christopher.nicosia@29palmsbominsn.govChemehuevi Imperial,Inyo,Riverside,San Bernardino 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 29 Palms Yonder Hospitality - Glamping Resort on Assessor’s Parcel Number 0614-121-15 (CRM TECH No. 4064), San Bernardino County.

Record: PROJ2023-005608
Report Type: List
of Tribes
Counties: San
Bernardino
NAHC Group: All
+- +
+- +

35 APPENDIX 3

CULTURAL RESOURCES RECORDED IN THE PROJECT AREA
(Confidential)
Available upon request to Qualified Professionals

City of Twentynine Palms
Ofland Hotel Initial Study
E
APPENDIX E: Geotechnical Report
Available on the City of Twentynine Palms Website:
www.ci.twentynine-palms.ca.us

GEOTECHNICAL INVESTIGATION

PROPOSED LUXURY OUTDOOR RESORT
TVvENTir,JINE PALlv1S HIGHWAY
TWTNTYNINE PAUvIS, CALIFORNIA
-Prepared ByS lad den Engineering
45090 Golf Center Suite F
Indio, California 92201
(760) 863-0713

Sladden Engineering
45090 Golf Center Parkway, Suite F, Indio, California 92201 (760) 863-0713 Fax (760) 863-0847 6782 Stanton Avenue, Suite C, Buena Park, CA 90621 (714) 523-0952 Fax (714) 523-1369 450 Egan Avenue, Beaumont, CA 92223 (951) 845-7743 Fax (951) 845-8863 www.sladdenengineering.com
December 18, 2023
29 Palms Hotel, LLC
4605 Post Oak Place Drive, Suite 280
Houston, Texas 77027
Subject:

Project:

Geotechnical Investigation
Proposed Luxury Outdoor Resort
APN 0614-121-15
Twentynine Palms Highway
Twentynine Palms, California
Project No. 544-23355
23-12-620
Sladden Engineering is pleased to present the results of the geotechnical investigation performed for the luxury outdoor resort proposed for the subject site (APN 0614-121-15) located on the south side of Twentynine Palms Highway (SR 62) between Shoshone Valley Road and Lear A venue in the City of Twentynine Palms, California. Our services were completed in accordance with our revised proposal for geotechnical engineering services dated October 25, 2023, and your authorization to proceed with the work. The purpose of our investigation was to explore the subsurface conditions at the site to provide recommendations for foundation design and the design of the various site improvements. Evaluation of environmental issues and hazardous wastes was not included within the scope of services provided.

The opinions, recommendations and design criteria presented in this report are based on our field exploration program, laboratory testing and engineering analyses. Based on the results of our investigation, it is our professional opinion that the proposed project should be feasible from a geotechnical perspective provided that the recommendations presented in this report are implemented in design and carried out through construction.

We appreciate the opportunity to provide service to you on this project. If you have any questions regarding this report, please contact the undersigned.

SER/me
Copies: PDF/Addres
Sladden Engineering
www.SladdenEngineering.com

GEOTECHNICAL INVESTIGATION

PROPOSED LUXURY OUTDOOR RESORT
APN 0614-121--15
TWENTYNINE PAUv1S HIGHWAY

TWENTYNINE PALMS, CALIFORNIA

TABLE OF CONTENTS
INTRODUCTION ................................................................................................................................... 1 PROJECT DESCRIPTION ...................................................................................................................... 1 GEOLCtGIC SE~fTI~JG ········~·-·················••oc••o•c••·········'············•--•-•·-··········••c"••a••···••c••····················•·o•······•- 3 SUBSURFACE CQI,JDIT'IONS ............... , ..... , ..................................... , .... "••••a••·••s••························•·•····•·-• 3 SEISMICITY AND FAULTING ..................................................................................................... ,. ...... 4 SITE-SPECIFIC GROUND MOTION Pl•,RAMETERS ............................... ., ....................................... 5 GEOLOGIC Hft__.,_ZARiDS ........................... , ........................ , .... , ..... ,. ..... , ......... , .................... o, •• , •. , •• s••···"••· 5 CONCLUSIONS ......... , .............................. , ..... , ........................................... "'·········································· 7 EARTHVvORK AND GRADING, .................. , .................. , .................................... ····'"···················· 7 Site Clearing ...... , ................. ., ........... , ............................................................................................ , .. 7 Preparation of Building Areas ........................................................................................................ 8 Compaction ....................................................................................................................................... 8 Shrinkage and Subsidence .............................................................................................................. 8 CONVENTIONAL SHALLOW SPREAD FOOTINGS ................................ , ..................................... 9 SLl\BS-Or-,J-GRADE ...... ,. ................................................................. , ...................................................... 9 PRELHviINARY PA VE1V1ENT DESIGN ............................ , ................................................................. 10 RETAINil',JG WALLS ......... ,. ................................ "'······· .... ,. ................................................................... 10 CORROSION SERIES ............................................................................................................................. 11 UTILITY TRENCH BA.CKFILL ............................................................................................................. 11 EXTERIOR CONCRETE FLATWORK ................................................................................................. 11 DRfa..II\TAGE .......................................... , ......................................................................... , ........................ 12 LIIvHTATIOJ\JS ............................. , ...... ., ................................................................................................... 12 ADDITIONAL SERVICES ..................................................................................................................... 12 REFERENCES ...................... , ........................................... , ...................................................................... 13 FIGURESAPPENDIX A

APPENDIXB
Site Location Map
Regional Geologic Map
Exploration Location Plan
Fault Zone Map
Flood Insurance Rate Map (FIRM)
Field Exploration
Laboratory Testing
Siadden Engineering
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APPEI',rrnx eTABLE OF CONTENTS (Continued)
Historical Earthquakes
Seismic Design Map and Report
Site-Specific Ground tviotion Parameters
Sladden Engineering
www.SladdenEngineering.com

Decen1ber 18r 2023 1

INTRODUCTION
Froject t,I o. 544-23355
23-12-620
This report ptesehts the results of the geotechnicai inve-stigation performed by Sladden Engineering (Sladden) for the luxury outdoor resort proposed for the subject site (APN 0614-121-15) located on the south side of Twentynine Palms Highway (SR 62) betvveen Shoshone Valley Road and Lear A venue in the City of Twentynine Falms, California. The site is located at approximately 34J 343 degrees north latitude and 116.1482 degrees west longitude. The approximate location of t½.e site is indicated on the Site Location Map (Figure 1 ).
()ur investigation v1as conducted to evaluate the engineering properties of the subsurface materials, to evaluate their in-situ characteristics, and to provide engineering recommendations a:nd design criteria for site preparatior,, foundation design and the design of various site improvements. This study also ir1cludes a revievv of published and unpublished geot2chnical and geological hterah.ire regarding seisrnicii:y at and neat the subject site.

PROJECT DESCRIPTION
Based o:n the provided Site Plan (BW, 2023), it is our understanding that the project v,.rill consist of constructing an outdoor resort consisting of approximately 130 detached cabins, e1npioyee housing, two (2) lodges, a swimrning pool, amenity spaces, and an outdoor native garden area. Concrete flatvvork, lartdscape areas, a,,d various associated site improvements are also anticipated. The nevv resort will be serviced by an on-site sewage disposal system consisting of septic ta,-.k(s), seepage pits and an advanced treatment package plant. For our analyses, we expect that the proposed structures v.rill consist of relatively lightweight wood-frame or light gauge steel frame structures supported on conventional shallow spread footings and concrete slab-on-grade.

Grading plans and finished floor elevations were not available at the time of this report. Sladden expects that grading VIill consist of minor cuts and fills to attain the design pad elevations. This does not include the recommended over-excavation and re-compaction of the surface soil ·withn.1. the building areas. Upon completion of the project plans, Sladden should be retained to confirm that the recommendations presented within this report are incorporated into the design and construction of the proposed project.

Structural foundation loads were not available at t.¾e time of this report. Based on our experience with relahvely lightweight wood-frame or light gauge steel frame structures, we expect that isolated colu:mn loads will be less than 20 kips and continuous wall loads wm be less than 2.0 kips per linear foot. H these assumed loads vary signifi.ca.,tly from the actual loads 1 we should be consulted to verify the applicability of the recommendations provided.

Stadden Engineering
ivww.SladdenEngineeringcom

December 18., 2023 ,.,
L
SCOPE OF SER.VICES
Project No . .544_-23355
23-12-620
The purpose of our investigation was to detennine specific engineering c.haracteristics of the surface and near-surface soil to develop foundation design criteria and recommendations for site preparation.

Specifically, our site characterization consisted of the following tasks:
§ Site reconnaissance to assess the existing surface conditions on and adjacent to the site. • Exca11ating eighteen (18) exploratory bores/percolation tesi: holes to depths between approximately 5 and 50 feet below the existing ground surface (bgs) to characterize the near-surface soil conditions.

Representative samples of the soil were classified in the field and retained for laboratory testing 3-i,d engineeri.'1g analyses.
" Performing laboratory testing on selected samples to evaluate their engineering characteristics. " Reviewing geologic literature and disorssing geologic hazards. " Perfonning engineering analyses to develop recommendations for foundation design and site preparation.
<> The preparation of this report summarizing our work at the site.

SITE CONDITIONS
The sites are formally identified by the County of San Bernardino as ,Ji,,PN 0614-121-15 and occupies approximately 15153 acres. At the time of our investigation, the majoriry of the property was vacant and occupied by scattered low-growth native vegetation. The northeastern portion of the property was occupied by discontinuous curb and gutter concrete sections constn1cted durir,g a previously proposed project. T'NO (2) water tanks are mapped adjacent to the southeastern property comer and a well site is mapped adjacent to the northeast properry cmT,eL The subject properry is near the elevation of Lhe adjacent properties and roadways and is generally bounded by an u,7-developed parcel to the south, Lear Avenue (if projected) to the west, Twentynine Palms Highway (SR 62) to the north and Shoshone Valley Drive to the immediate east.

Based on our review of the Sunfair 7.5-J\,finute Quadrangle Maps (USGS, 2018), the site is situated at elevations ranging from approximately 2,600 to 2,500 feet above mean sea level (MSL). Surface gradients on the site descend to the north at inclinations of ten horizontal to one vertical (lOH:lV) and less.

No natural ponding of water or surface seeps were observed at or near the site during our investigation conducted on December 6 and December 7, 2023. Site drai.nage appears to be conh·olled via sheet flow and surface infilh·ation. No significant drainage courses were identified on the site during our field investigation.

Sladden Engineering
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Decerrj_ber 18,, 2023 3
(;EOLOGIC SETTII\TG
Pioject f,Jo. 544--2335.5
23-12-620
T'ne site 1s located within the Transverse Ranges Geomorphic province. The Transverse Ranges are characterized by roughly east-west trending, convergent (north-south compressional) defonnational structural features. The convergent deformational features of the Transverse Ranges are a result ofnorthsouth cn1stal shortir•g due to plate tectonics, local folding and uplifting of the mountains, and lowering of the intervening valleys, along with propagation of thntst faults {including blind thrusts) and infilling of the valley basins with sediments. The Transverse Ranges are considered to be one of the most r3-pidly rising orogenic regions on Earth.

The site has been mapped by Dibblee (1968) to be immediately underlain by alluvium (Qa). The regional geologic setting for the site vicinity is presented or; the Regional Geologic J<.;Iap (Figure 2).

SUBSURFACE CONDITIONS
The subsurface conditions at the site were investigated by excavafu,g eighteen (18) exploratory boreholes/percolation test holes to depths behveen approximately 5 and 50 feet bgs The approximate exploratory locations are Hlustrated 011 the Exploration Location Plan (Figure 3). The boreholes were advanced usir,g a truck-mounted drill rig (Mobile B-61) equipped with 8-inch outside diameter hollow stem augers. A representative of Sladden was on-site to log the materials encountered and retrieve samples for laboratory testing and engineeri.i,g analyses.

During our field investigation, native alluvium consisting of interbedded silty sand (SM) and sand (SWSM) were encountered to the maximum explored depth of 50 feet bgs. Generally, the alluvial materials appeared light brown to strong brown, dry, loose to dense, and fine- to coarse-grained.

The final logs represent our interpretation of the contents of the field logs, and the results of the laboratory observations and tests of the field samples. The final logs are included in Appendix A of this report. The stratification lines represent the approximate boundaries between soil types although the transitions rnay be gradual.

Groundwater was not encountered during our field investigation to the maximum explored depth of 50 feet bgs. Information regarding the approximate depth to groundwater provided by the California Department of Vvater Resources online database indicates that the depth to groundwater is in excess of 150 feet below the existing ground surface in the vici11ity of the site. The following table provides a summary of the recorded groundwater depths i..n the project vicinity.

STATE WELL
01N08E33J001S
01N08E34M001S
01N08E34N001S
01N08E30J001S
01N08E30N001S
01N08E36H002S i
TABLE1

GROUNDWATER DEPTHS

LAT/LONG DISTANCE (KM)

34.1253/-116.1469 1.00

34.1252/-116.1413 1.19

34.1227/-116.1388 1.55

34.1416/-116.1793 2.99

34.1352/-116.1927 4.11

34.1281/-116.0939 5.05

DATE DEPTH(FT)
03/28/2008 417.94
09/20/2007 303.77
04/26/2006 242.69
02/07/2023 155.62
02/17/1994 307.67
08/31/1993 217.08
Sladden Engineering
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Decer.ctber 18, 2023 4 Project No. 544-23355
23-12-620
SEISMICHYANDFAULT!NG
The southv<7estern United States is a tectonically active and struchirally complex regionr dominated by northwest-trendh,g dextral faults. TI1e faults of i:he region are often part of complex fault systems, composed of numerous subparallel faufts which spfay or step from main fault traces. Strong seismic shaking could be produced by any of these faults during the design life oi the proposed project.

We consider the most significant geologic hazard to the project to be the potential for moderate to strong seismic shaking that is likely to occur during the design lifo of the project. The proposed project is located in the highly seismic Southern California region withi._11 the influence of several fault systems. A Holocene-active active fault is defined by the State of Caiifomia as a fault that has exhibited surface displacement within the Holocene time (about the last 11,700 years). A pre-Holocene fault is defined by the State as a fault whose recency of past rnovement is older than 11,700 years.

A5 previously stated, the site has been subjected to sb:ong seismic shaking related to active faults faat traverse through the region. Smne of the more significant seismic events near the subject site within recent times include: M6.0 North Pa!m Springs (1986), M6.1 Joshua Tree (1992), IvI7.3 Landers (1992}, J\,16.2 Big Bear (1992), M?.1 Hector Mine (1999) and 7.1 Ridgecrest (2019).

A search of historical earthquakes between 1932 and 2023 has been perfonned using the iH.JSS Comprehensive Earthquake Catalog (USGS, 2023a) for earthquakes within a 20-kilometer search radius of the site. The list of historical earthquakes is included within Appendix C.

Table 2 lists the closest knmvn potentially active faults that ,vere generated in part using the Quaternary Fault and Fold Database of the United States (USGS, 2023b ), as modified using the fault parameters from The Revised 2002 California Probabilistic Seismic Hazard Maps (Cao et al, 2003), and the Southern Earthquake Data Center (SCEDC, 2023). This table does not identify the probability of reactivation or the on-site effects from earthquakes occurring on any of the other faults h, the region.

TABLE2

CLOSEST KNOWN ACTIVE FAULTS
Fault Name
Pinto Mountain
Calico - Hidalgo
Camp Rock - Emerson - Copper Mountain
Mesquite Lake
Pisgah - Bullion
Johnson Valley Fault
Eureka Peak
B1..unt Mountain
San Andreas Coachella
Distance Maximum
(Km)

0.8 3.1

3.9 11.1

12.8 25.2

21.1 24.0

34.2 Event

7.3 7 ,.,
.J

7.0 '7 ".l f .,J

7.3 7~
, . .:i

6.4 6.5

7.5 Sladden. Engineering
www.SladdenEngineering.com

December 18, 2023 5

SITE SPEOFIC GROUND MOTION PARAMETERS
Project No. 544-23355
23-12-620
Sladden has reviewed the 2022 California Building Code (CBC) and ASCE7-16 and developed sitespecific grouncCmotion parameters for the subject site. The project site=specific groi.ma.-moffon parameters are summarized in the following table and included within Appendix D. The project Structural Engineer should verify that all design parameters provided are applicable for the subject project.

TABLE3

GROUND MOTION PARAMETERS
Latitude / Longitude 34.1343/-116.1482
Risk Category II
Site Class D
Code Reference Documents ASCE 7-16; Chapter 11 & 21
Description Type Map Based Site-Specific
MCER Ground Motion (0.2 second period) Ss 1.861 ---
MCER Ground Motion (1.0 second period) S1 0.697 ---
Site-Modified Spectral Acceleration Value SMS 1.861 2.150 Site-Modified Spectral Acceleration Value SM1 Null 1.815 Numeric Seismic Design Value at 0.2 second SA Sos 1.241 1.433 Numeric Seismic Design Value at 1.0 second SA Sm Null 1.210 Site Amplification Factor at 0.2 second Fa 1 1
Site Amplification Factor at 1.0 second Fv Null 2.5
Site Peak Ground Acceleration PGAM 0.903 0.837

GEOLOGIC HAZARDS
The subject site is located in an active seismic zone (Figure 4) and will likely experience strong seismic shaking during the design life of the proposed project. In general, the intensity of ground shaking will depend on several factors including: the distance to the earthquake focus, the earthquake magnitude, the response characteristics of the underlying materials, and the quality and type of construction. Geologic hazards and their relationship to the site are discussed below.

L Surface Rupture. Surface rupture is expected to occur along preexisting, known active fault traces. However, surface rupture could potentially splay or step from known active faults or rupture along unidentified traces. Based on our review of Dibblee (1968), Jennings (1994), and CDMG (1988), known faults are not mapped on or projecting towards the site.

The subject parcel is not located in a State of California delineated fault zone (Figure 4). In addition, no signs of active surface faulting were observed during our review of non-stereo digitized photographs of the site and site vicinity (Google Earth, 2023). Finally, no signs of active surface fault rupture or secondary seismic effects (lateral spreading, lurching etc.) were identified during our field investigation. Therefore, it is our opinion that risks associated with primary surface ground rupture should be considered "low".

Sladden Engineering
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December 18, 2023 6 Project No. 544-23355
23-12-620
II. Ground Shaking. The site has been subjected to past ground shaking by faults that traverse through the region. Strong seismic shaking from nearby active faults is expected to produce strong seismic shaking during the design life of the proposed project. The sitemodified peak ground acceleration is estimated to be oJ~37g.

III. Liquefaction. Liquefaction is the process in which loose, saturated granular soil loses strength as a result of cyclic loading. The strength loss is a result of a decrease in granular sand volume and a positive increase in pore pressures. Generally, liquefaction can occur if all of the following conditions apply; liquefaction susceptible soil, groundwater within a depth of 50 feet or less, and strong seismic shaking.

Based on the depth to groundwater in the project vicinity, and the relatively dense nature of the alluvial materials underlying the site, risks associated with liquefaction are considered "negligible".

IV. Tsunamis and Seiches. Because the site is situated at an inland location and is not immediately adjacent to any impounded bodies of water, risk associated with tsunamis and seiches is considered "negligible".

V. Slope Failure, Land Sliding, Rock Falls. No signs of slope instability in the form of landslides, rock falls, earthflows or slumps were observed at or near the subject site. The site is located on relatively level ground and not immediately adjacent to any hillsides.

Based on our field observations of the site vicinity, risks associated with slope instability should be considered "negligible".

VI. Expansive Soil. Generally, the surface soil consists of sand (SM/SW). Based on the results of our laboratory testing (EI=0), the materials underlying the site are considered to have a "negligible" expansion potential.

VII. Static Settlement. Static settlement resulting from the anticipated foundation loads should be tolerable provided that the recommendations included in this report are considered in foundation design and construction. The ultimate static settlement is expected to be less than 1 inch when using the recommended allowable bearing pressures. As a practical matter, differential static settlement between footings can be assumed as one-half of the total settlement.

VIII. Subsidence. Land subsidence can occur in valleys where aquifer systems have been subjected to extensive groundwater pumping, such that groundwater pumping exceeds groundwater recharge. Generally, pore water reduction can result in a rearrangement of skeletal grains and could result in elastic (recoverable) or inelastic (unrecoverable) deformation of an aquifer system.

Locally, no fissures or other surficial evidence of subsidence were observed at or near the subject site. The potential for subsidence-related settlement is considered "negligible".

Sladden Engineering
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December 18, 2023 7 Project No. 544-23355
23-12-620
IX. Debris Flows. Debris flows are viscous flows consisting of poorly sorted mixtures of sediment and water and are generally initiated on slopes steeper than approximately six horizontal to one vertical (6H:1V) (Boggs, 2001). Based on the gently sloping nature of the s~t':c1!1:cl_tll~_compo~~f:i_e>11 e>f the surface soil, we judge that the risks associated with debris flows should be considered "negligible".

X. Flooding and Erosion. No signs of flooding or erosion were observed during our field investigation. The project site is located within a "Zone X" flood designation (Figure 5) Risks associated with flooding and erosion should be evaluated and mitigated by the project design Civil Engineer.

CONCLUSIONS
Based on the results of our investigation, it is our professional opinion that the project should be feasible from a geotechnical perspective provided that the recommendations provided in this report are incorporated into design and carried out through construction. The main geotechnical concern is the presence of loose and potentially compressible near-surface soil throughout the subject site.

We recommend that remedial grading within the proposed building areas include over-excavation and re-compaction of all loose native soil encountered during grading. Specific recommendations for site preparation are presented in the Earthwork and Grading section of this report.

Caving did occur to varying degrees within each of our exploratory bores and the surface soil may be susceptible to caving within deeper excavations. All excavations should be constructed in accordance with the normal CalOSHA excavation criteria. On the basis of our observations of the materials encountered, we anticipate that the subsoil will conform to that described by CalOSHA as Type C. Soil conditions should be verified in the field by a "Competent person" employed by the Contractor.

The following recommendations present more detailed design criteria that have been developed on the basis of our field and laboratory investigation.

EARTHWORK AND GRADING
All earthwork including excavation, backfill and preparation of the primary foundation and/or slab bearing soil should be performed in accordance with the geotechnical recommendations presented in this report and portions of the local regulatory requirements, as applicable. All earthwork should be performed under the observation and testing of a qualified soil engineer. The following geotechnical engineering recommendations for the proposed project are based on observations from the field investigation program, laboratory testing and geotechnical engineering analyses. a. Site Clearing: Areas to be graded should be cleared of any existing vegetation, root systems, underground utilities and debris. All areas scheduled to receive fill should be cleared of old fills and any irreducible matter. The unsuitable materials should be removed off site. Voids left by obstructions should be properly backfilled in accordance with the compaction recommendations of this report.

Sladden Engineering
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December 18, 2023 8 Project No. 544-23355
23-12-620
b. Preparation of Building Areas: To provide firm and uniform foundation bearing conditions, we recommend over-excavation and re-compaction throughout the proposed new building areas. All artificial fill soil and low-density near-surface native soil should be removed to a depth of approximately 3 feet below existing grade or 2 feet below the bottom of the footings, whichever is deeper. Rem~di;lgrading sho;ldextin.d laterally a minimum of five feet beyond the building perimeter. The native soil exposed by over-excavation should be scarified, moisture conditioned to near optimum moisture content, and compacted to at least 90 percent relative compaction prior to fill placement. The previously removed soil may then be replaced as engineered fill as recommended below.
c. Compaction: Soil to be used as engineered fill should be free of organic material, debris, and other deleterious substances, and should not contain irreducible matter greater than three inches in maximum dimension. All fill materials should be placed in thin lifts, not exceeding six inches in a loose condition. If import fill is required, the material should be of a low to non-expansive nature and should meet the following criteria:

Plastic Index
Liquid Limit
Less than 12
Less than35
Percent Soil Passing #200 Sieve
Maximum Aggregate Size
Between 15% and 35%
3 inches
The subgrade soil and all fill material should be compacted with acceptable compaction equipment to at least 90 percent relative compaction. The exposed subgrade soil should be observed by a representative of Sladden Engineering prior to fill placement. Compaction testing should be performed on all lifts in order to ensure proper placement of the fill materials. Table 4 provides a summary of the excavation and compaction recommendations.

TABLE4

SUMMARY OF RECOMMENDATIONS
*Remedial Grading Over-excavation and re-compaction within the building envelope and extending laterally 5 feet beyond the building limits and to a minimum depth of 3 feet below existing
grade or 2 feet below the bottom of the footings, whichever is deeper.

Native / Import Engineered Fill Place in thin lifts not exceeding 6 inches in a loose condition, compact to a minimum of 90 percent relative compaction
within 2 percent of the optimum moisture content.
* Actual depth may vary and should be determined by a representative of Sladden Engineering in the field during construction.
d. Shrinkage and Subsidence: Volumetric shrinkage of the material that is excavated and replaced as controlled compacted fill should be anticipated. We expect that this shrinkage should be between 10 and 20 percent. Subsidence of the surfaces that are scarified and compacted is expected to be between 1 tenth and 2 tenths of a foot. This will vary depending upon the type of equipment used, the moisture content of the soil at the time of grading and the actual degree of compaction attained.

Sladden Engineering
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December 18, 2023 9

CONVENTIONAL SHALLOW SPREAD FOOTINGS
Project No. 544-23355
23-12-620
Conventiona_!shallow spread footings are expected to provide adequate support for the proposed structures. All footings sh~nild be founded upon properly compacted en.gineeredfillsoifand. should have a minimum embedment depth of 12 inches measured from the lowest adjacent finished grade.

Continuous and isolated pad footings should have minimum widths of 12 inches and 24 inches, respectively. Continuous and isolated pad footings supported upon properly compacted engineered fill soil may be designed using allowable bearing pressures of 1800 and 2000 pounds per square foot (psf), respectively. Allowable increases of 200 psf for each additional 1 foot of width and 250 psf for each additional 6 inches of depth may be used if desired. The maximum allowable bearing pressure should be 3,000 psf. The allowable bearing pressures apply to combined dead and sustained live loads. The allowable bearing pressures may be increased by one-third when considering transient live loads, including seismic and wind forces.

Based on the recommended allowable bearing pressures, the total static settlement of the conventional shallow spread footings is anticipated to be less than one-inch provided that foundation area preparation conforms to the recommendations included in this report. Static differential settlement is anticipated to be approximately one-half of the total static settlement for similarly loaded footings spaced up to approximately 50 feet apart.

Lateral load resistance for the shallow spread footings will be developed by passive pressure against the sides of the footings below grade and by friction acting at the base of the footings. An allowable passive pressure of 250 psf per foot of depth may be used for design purposes. An allowable coefficient of friction

0.45 may be used for dead and sustained live loads to compute the frictional resistance of the footing placed directly on compacted fill. Under seismic and wind loading conditions, the passive pressure and frictional resistance may be increased by one-third.

All footing excavations should be observed by a representative of the project geotechnical consultant to verify adequate embedment depths prior to placement of forms, steel reinforcement or concrete. The excavations should be trimmed neat, level and square. All loose, disturbed, sloughed or moisturesoftened soils and/or any construction debris should be removed prior to concrete placement. Excavated soil generated from footing and/or utility trenches should not be stockpiled within the building envelope or in areas of exterior concrete flatwork. All footings should be reinforced in accordance with the project Structural Engineer's recommendations.

SLABS-ON-GRADE
To provide uniform and adequate support, concrete slabs-on-grade should be placed on properly compacted engineered fill soil as outlined in the previous sections of this report. The slab subgrade should remain near optimum moisture content and should not be permitted to dry prior to concrete placement. Slab subgrades should be firm and unyielding. Disturbed soil should be removed and replaced with engineered fill soil compacted to a minimum of 90 percent relative compaction.

Sladden Engineering
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December 18, 2023 10 Project No. 544-23355
23-12-620
Slab thickness and reinforcement should be determined by the Structural Engineer. We recommend a minimum slab thickness of 4.0 inches and minimum reinforcement of #3 bars at 24 inches on center in both directions. All slab reinforcement should be supported on concrete cp.airs to ensure that reinforcem~11t ~ P!c:l_~~? c1t ~li:J.b 11:1}<:l-height. Final floor slab design and reinforcement should be determined by the Structural Engineer.

Slabs with moisture sensitive surfaces should be underlain with a moisture vapor retarder consisting of a polyvinyl chloride membrane such as 10-mil visqueen, or equivalent. All laps within the membrane should be sealed and at least 2 inches of clean sand should be placed over the membrane to promote uniform curing of the concrete. To reduce the potential for punctures, the membrane should be placed on a pad surface that has been graded smooth without any sharp protrusions. If a smooth surface can not be achieved by grading, consideration should be given to placing a thin leveling course of sand across the pad surface prior to placement of the membrane.

PRELIMINARY PAVEMENT DESIGN
Asphalt concrete pavements should be designed in accordance with Caltrans Highway Design Manual based on R-Value and Traffic Index. An R-Value of 50 was assumed to develop the following preliminary pavement design sections. For Pavement design, a Traffic Index (TI) of 5.5 was used for the on-site pavement limited to automobile traffic and 6.5 was used when considering heavy duty pavement. We assumed Asphalt Concrete (AC) over Class II Aggregate Base (AB). The preliminary flexible pavement design is as follows:

ON-SITE ASPHALT PAVEMENT SECTION LA YER THICKNESS
Pavement Material Recommended Thickness
TI = 5.5 (Light Duty) TI = 6.5 (Heavy Duty)
Asphalt Concrete Surface Course 3.0 inches 3.0 inches
Class II Aggregate Base Course 4.0inches 6.0inches
Compacted Subgrade Soil 12.0 inches 12.0 inches
Asphalt concrete should conform with the Standard Specifications for Public Works Construction ("Greenbook") or CalTrans. Class II aggregate base should conform to Greenbook or Caltrans Standard Specifications. The aggregate base material should be compacted to at least 95 percent of the maximum dry density as determined by ASTM Method D 1557.

RETAINING WALLS
Minor retaining walls may be required to accomplish the proposed construction. Cantilever retaining walls may be designed using "active" pressures. Active pressures may be estimated using an equivalent fluid weight of 35 pcf for gently sloping (less than 3H:1V) native backfill soil acting in a triangular pressure distribution with drained backfill conditions. For steeper slopes, an active equivalent fluid pressure of 55 pcf should be used. "At Rest" pressures should be utilized for restrained walls. At rest pressures may be estimated using an equivalent fluid weight of 55 pcf for native backfill soil with level drained backfill conditions. At rest pressures should be increased to 75 pcf for sloped backfill conditions.

Sladden Engineering
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Decnnber 18, 2023 11 Project 1\1 o. 544-23355
23-12-620
11\le recon11L1ertd that a bacl<:: drain system be provided be.hirui all retair1ing v,;1al1s or t:hat tl1e vvalls be designed for full hydrostatic pressures. The back drains should consist of a heavy walled, four inch diameter, perfor.:lted pipe sloped to drai.'l. to outlets by gravity, and of dean, free-drair1ing, three-quarter to one and one-half inch crushed rock or graveL The crushed rock or gravel shou.id extend to {vithm one foot of the surface. The upper one foot should be backfilled vrith compacted, fii,e-grained soil to exclude surface water. A Mirafi 140N (or equivalent) filter cloth should be placed between the on-site native rnaterfal and the drain rnck
VVe recommend that the gro11nd surface behind retaining walls be sloped to drain. Under ;10 circumstances sho1.1ld the surface v1ater be diverted~ iT1to back drains. VV11.ere n1igration of n1-oisture through walls would be detTimental, the vvalfr; should be waterproofed.

CORROSION SERIES
The soluble sulfate concentrations of the surface soil were determined to be 40 parts per million (ppm).

The native soil falls withi,, the "negligible - SO" sulfate exposure category. The use of Type V cement and special sulfate resistant concrete mixes should not be necessary.

The pH levels of the surface soil was determined to be 7.3 and 8.0. Based on soluble chloride concentration testing (30 ppm) the soil falls withi..n the "negligible - CO" chloride exposure category. The minimum resistivity of the surface soil was found to be 7,000 and ,t600 ohm-cm, which suggests the site soil is considered to have a "low" corrosion potential with respect to ferrous metal installations. A corrosion expert should be consulted regarding appropriate corrosion protection measures for corrosionsensitive installations.

UTILITY TRENCH BACKFILL
All utility trenc..h. backfill should be compacted to a minimum of 90 percent relative compaction. Trench backfill materials should be placed in lifts no greater than six inches in a loose condition, moisture conditioned (or air-dried) as necessary to achieve near optimum moistuTe content, and mechanically compacted in place to a minimum of 90 percent relative compaction. A representative of the project soil engineer should test the backfill to verify adequate compaction.

EXTERIOR CONCRETE FLATWORK
To minimize cracking of concrete flatwork, the sub grade soil below concrete flan.vork areas should first be compacted to a minimlLrn of 90 percent relative compaction. A representative of the project geotechnical consulta.nt should observe and verify the density and moisture content of the soil prior to concrete placement
Sladden E11gi.neering
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December 18, 2023 12

DRAINAGE
Project No. 544-23355
23-12-620
All final grades should be provided with positive gradients away from foundations to provide rapid removal of surface water runofTto an adequate discharge point. No water should be allowed to be pond on or immediately adjacent to foundation elements. To reduce water infiltration into the subgrade soil, surface water should be directed away from building foundations to an adequate discharge point.

Subgrade drainage should be evaluated upon completion of the precise grading plans and in the field during grading.

LIMITATIONS
The findings and recommendations presented in this report are based upon an interpolation of the soil conditions between the exploratory locations and extrapolation of these conditions throughout the proposed building areas. Should conditions encountered during grading appear different than those indicated in this report, this office should be notified.

The use of this report by other parties or for other projects is not authorized. The recommendations of this report are contingent upon monitoring of the grading operation by a representative of Sladden Engineering. All recommendations are considered to be tentative pending our review of the grading operation and additional testing, if indicated. If others are employed to perform any soil testing, this office should be notified prior to such testing in order to coordinate any required site visits by our representative and to assure indemnification of Sladden Engineering.

We recommend that a pre-job conference be held on the site prior to the initiation of site grading. The purpose of this meeting will be to assure a complete understanding of the recommendations presented in this report as they apply to the actual grading performed.

ADDITIONAL SERVICES
Once completed, final project plans and specifications should be reviewed by use prior to construction to confirm that the full intent of the recommendations presented herein have been applied to design and construction. Following the review of plans and specifications, observation should be performed by the Soil Engineer during construction to document that foundation elements are founded on/or extend into the properly compacted soil, and that suitable backfill soil is placed upon competent materials and properly compacted at the recommended moisture content.

Tests and observations should be performed during grading by the Soil Engineer or his representative in order to verify that the grading is being performed in accordance with the project specifications. Field density testing shall be performed in accordance with acceptable ASTM test methods. The minimum acceptable degree of compaction should be 90 percent for engineered fill soil and 95 percent for Class II aggregate base as obtained by ASTM Test Method D1557. Where testing indicates insufficient density, additional compactive effort shall be applied until retesting indicates satisfactory compaction.

Sladden Engineering
www.SladdenEngineering.com

December 18, 2023 13

REFERENCES
Project No. 544-23355
23-12-620
Boggs, S. Jr., 2001, "Principles of Sedimentology and Stratigraphy", Prentice Hall, third edition Boundary Works (BW), 2023 Yonder - 29 Palms, Site Plan, A0.01.

Building Seismic Safety Council (BSSC), 2014, Earthquake Scenario Event Set webpage; available at:
https://usgs.maps.arcgis.com/apps/webappviewer/index.html?id=14d2f75c7c4f4619936dac0d14el e468
California Building Code (CBC), 2022, California Building Standards Commission.

California Department of Conservation (CDOC), 2023, Earthquake Zones of Required Investigation; available at: https://maps.conservation.ca.gov/cgs/EOZApp/app/ California Department of Water Resources (CDWR), 2023, Historical Data by Well-Map Interface, available at: https://wdl.water.ca.gov/waterdatalibrary/ California Division of Mines and Geology (CDMG), 1988, State of California Special Studies Zones, Sunfair Quadrangle.

Cao T., Bryant, W.A., Rowshandel B., Branum D., Wills C.J., 2003, "The Revised 2002 California Probabilistic Seismic Hazard Maps".

Dibblee, T.W., 1968, Geologic Map of the Twentynine Palms Quadrangle, San Bernardino and Riverside Counties, California; Map 1-561.

FEMA, 2008, National Flood Insurance Program, Flood Insurance Rate Map, Panel 8175 of 9400, Map No. 06071C8175H, Map Revised August 28, 2008.

GoogleEarth.com, 2023, Vertical Aerial Photograph for the Twentynine Palms area, California, Undated, Variable Scale.

Jennings, Charles W. (Compiler), 1994, Fault Activity Map of California and Adjacent Areas, California Division of Mines and Geology, Geologic Data Map No. 6
Southern California Earthquake Data Center (SCEDC), 2023, Significant Earthquakes and Faults; available at: https://scedc.caltech.edu/
Structural Engineer Association (SEA), 2023, Seismic Design Maps; available at:
https://seismicmaps.org/
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December 18, 2023 14 Project No. 544-23355
23-12-620

REFERENCES
(Continued)
United States Geological Survey (USGS), 2018, Sunfair 7.5 Minute Quadrangle Map, 1:24000.

United States Geological Survey (USGS), 2023a, Earthquake Catalog Search; available at:
https://earthquake. usgs. gov/ earthquakes/ search/
United States Geological Survey (USGS), 2023b, Quaternary Fault and Fold Database; available at:
https:// geohazards. usgs.gov /hazards/interactive/
United States Geological Survey (USGS), 2023c, Risk-Targeted Ground Motion Calculator; available at:
https://earthquake.usgs.gov / designmaps/rtgm/
United States Geological Survey (USGS), 2023d, Unified Hazard Tool; available at:
https://earthquake.usgs.gov/hazards/interactive/
Sladden Engineering
www.SladdenEngineering.com Page 1013 of 1452

FIGURES

SITE LOCATION MAP

REGIONAL GEOLOGIC MAP

EXPLORATION LOCATION PLAN

FAULT ZONE MAP

FLOOD INSURANCE RATE MAP (FIRM)
Sladden Engineering
www.SladdenEngineering.com Page 1014 of 1452
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SITE LOCATION MAP
544-23355
23-12-620
Date: December 18, 2023
FIGURE
1

SEDIMENTARY DEPOSITS
Q~
Sud'icial sediments
Qs, u:indl>lown sand
Qa, alhtuiu,n
Qc, cla-.,
l Qdf j
Dissected alluvial fan graYel
Older surficial sediments
Qoa, ofdcr a.Uutiium
Qog, older gra,•d and sar,,d
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REGIONAL GEOLOGIC MAP
544-23355
ortNumber: 23-12-620
Sladden Engineering Date: December 18, 2023
L
FIGURE
2

Sladden Engineering

EXPLORATION LOCATION PLAN FIGURE
3 Date: December 18, 2023
Project Number: 544-23355
Report Number: 23-12-2023
LEGEND 
 Stormwater Percolation Test Location
 BH-11 (SP-2)
SW-7
Borehole Location (Seepage Pit Percolation Test Location)  SW-4
 SW-5
 SW-6
 SW-7
 SW-3
 SW-2
 SW-1
BH -10
 BH-1 (SP-1)  BH-2 (SP-2)
BH -11
BH -3
BH -4
BH -5
BH -6
BH -7
BH -8
BH -9
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M.AJII IEXPLANA"TtON
Jllobntially Active Feul'tll
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Faults considered to have beer> ac1ive during Holocene rime and to have a 1elat,vely high potential for surface rupture. solid line where accurate1y locatea, long dash where approx,metely located, short dast> where inferred. dotted where concHled: query (?) 1nd,cates add•tional uncertainty. Evidence of h1stor1c offset indicated by year of earthquake-associated event or C for displacement caused by cre~or QQssible c~ hese are del1neate-d as stra1ght-hne segments that connect encirc,eel turning po,n:s so as to def ne ;,pecial studies zor>e segmerns.

Seaward projection of zone boundary.

FAULT ZONE MAP
Pro·ect Number: 544-23355
23-12-620
Sladden Engineering Date: December 18, 2023
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LEGEND

SPEOAL FLOOD HAZARD AREAS SUBJECT TO INUNDATION
BY THE I% ANNUAL CHANCE FLOOD
The J% annual flOod (.100-year Rood}, also knOwn as the base fbod, IS tne flood thllt has a 1% ~nee. of being eql.litled or exoeeded in any QIYel1 ','eil'. The Spe:;ial Flood Hazard Aleo Is the area subject t:o floocfing D'f tne 1 % annual chance flood. Areas or Spajal Rooo Hazard Include zones A, AE., AH, PD, AA, A99. v. ano YE. Tl'le ease FIOod Bevabal is the water-st.uface efl!vabon d tne 1-0'.¼\o annual chance rlcod.

ZONE A
ZONEAE
Z"ONE-AK

ZONE AO

ZONE AR
ZONEA99
ZONEV
No Base Fbod Eie¥a\ioos determined.
~ FlOOCI ElevabOnS oetenrunecl.
-•-----on: lo T!ei!r{UwalJ/ •- or-"°""lllg)~.,.,.,.,.-
E'JevatlOOS oe1,1mJ11e<1.

Flood depth, de l to 3 feet(usually shm flow on siop;ng tem,;nJ; aven,ge dePUts dl;lermlne1. For areas of atuvlal fan floo(llng, 'P-looties: also deta'mined.

Special Rood Ka.lard Area formeri)' pnxecteo from the 1% annual chatlce nooct by a flood conuof system I.hat Wei$ 5Ubsiecf.Jer1\ly decertlf~. Zane AR 1nd,cat.es that the former flood corvol system I.\ betf9 restofed to prOV!de:
pr-oti'!dion from ~ 1 % annual chance or ~r flood.

P.,.,. 10 be o,otected from l % •mwl d1<1nte flood by • """"'°' "- protectJon .system under' constrl.d.ion; no Base Flood Elevitions dele"mlne:I.

Coastal flood zone with velocity hazard (wave actiOO); oo Base Flood Elevations ~lned.

Coastal nocx, ~ wrth vdoocy hau•d (WiM! actJoo);
Elelatons de!em1lned.

FLOODWAY AREAS IN ZONE AE
The tlood...-ay 1s the channl!I of a stream pus any ad~t fkxxlpl.ain areas that must ~ kA!!pt free ot encroachmEnt so I.hat the 1 tro annual Char'ICe flood can be earned vnlhoul substanbat iotreases " t1ood negt,ts.

ZONEX
ZONEX
ZONED

OTHER FLOOD AREAS
AreM cl 0.2% annt..ial ~ fbod; breBS d 1% annual chanc:e: flood vrith average depths or less than 1 root or with drainage area.s less than l square rrtJe; and areas proC:ecte:d t,v l"-'ees from l % annual chance flood.

OTHER AREAS
Areas detem11oed to be outside the 0.2% aMual diance nxx:lplam.

Areas 1n whtCh nooc, hazardS are u.ndetermme:J, but possible. ~ COAST AL BARRIER RESOURCESYSTEM (CBRS) AREAS
c:;§::) OTHERWISE PROTECTED AREAS (OPAS)
CBRS M-eM Md OPM are non'M\ly k.Xllled wlt.htn or ad:jbeel'\to Special Flood Hazard Are!ls.. 31 29
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Palms
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FLOOD INSURANCE RATE MAP (FIRM)
Pro·ect Number: 544-23355
23-12-620
Sladden Engineering Date: December 18, 2023
•· lO
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22 FIGURE
5

APPENDIX A

FIELD EXPLORATION
Sladden Engineering
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APPENDIX A

FIELD EXPLORATION
For our field investigation eighteen (18) exploratory bores/percolation test holes were excavated onsite.

Continuous logs of the materials encountered were made by a representative of Sladden Engineering.

Materials encountered in the test pits and test holes were classified in accordance with the Unified Soil Classification System.

Representative undisturbed samples were obtained within our borings by driving a thin-walled steel penetration sampler (California split spoon sampler) or a Standard Penetration Test (SPT) sampler with a 140 pound automatic-trip hammer dropping approximately 30 inches (ASTM D1586). The number of blows required to drive the samplers 18 inches was recorded in 6-inch increments and blowcounts are indicated on the boring logs.

The California samplers are 3.0 inches in diameter, carrying brass sample rings having inner diameters of

2.5 inches. The standard penetration samplers are 2.0 inches in diameter with an inner diameter of 1.5 inches. Undisturbed samples were removed from the sampler and placed in moisture sealed containers in order to preserve the natural soil moisture content. Bulk samples were obtained from the excavation spoils and samples were then transported to our laboratory for further observations and testing.

Sladden Engineering
www.SladdenEngineering.com

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Completion Notes:

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Equipment: Mobile B-61 Date Drilled: 12/6/2023
Elevation: 2505 Ft. MSL Boring No: BH-1 (SP-1)
Description
Silty Sand (SM); strong brown, dry, medium dense, fine- to coarsegrained (Qa).

Sand (SW-SM); light brown, dry, medium dense, fine- to coarse-grained (Qa).

Silty Sand (SM); light brown, dry, medium dense, fine- to coarsegrained (Qa).

Sand (SW-SM); strong brown, dry, dense, fine- to coarse-grained (Qa).

Sand (SW-SM); strong brown, dry, dense, fine- to coarse-grained (Qa).

Silty Sand (SM); strong brown, dry, fine- to coarse-grained (Qa).

PROPOSED OUTDOOR RESORT
TWENTYNINE PALMS HIGHWAY; APN 0614-121-15
Project No: 544-23355
1-~--------------------1 Page Report No: 23-12-620 1

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.§ .,. .... p.. :::s
0 s .8 "' -t u "' "' :::s -·<A· .. i,:-. "' -·,E ---~-s-··- ;::
0 ~ "' p.. ~ ~ 5 :::s X i:c 1:0 ><l ~ ~ 0
4 5 9 3.9 0.7
20 24 27 5.2 0.9 111.9
11 13 17 7.9 1.4
19 25 34 4.7 0.8 109 .5
Completion Notes:

Terminated at -50 Feet bgs.

Backfilled to 40 Feet for Percolation Testing
No Bedrock/Groundwater/Seepage Encountered.
2 4
6 8
12 14
16 18
20 22
26 28
30 32
34 36
38 40
42 44
46 48
50 BORELOG
Equipment: Mobile B-61 Date Drilled: 12/6/2023
Elevation: 2505 Ft. MSL Boring No: BH-2 (SP-2)
Description
Silty Sand (SM); light brown, dry, fine- to coarse-grained (Qa).

Sand (SW); light brown, dry, medium dense, fine- to coarse-grained (Qa).

Sand (SW-SM); light brown, dry, dense, fine- to coarse-grained (Qa).

Sand (SW-SM); light brown, dry, medium dense, fine- to coarse-grained (Qa).

Sand (SW-SM); light brown, dry, dense, fine- to coarse-grained (Qa).

Silty Sand (SM); light brown, dry, fine- to coarse-grained (Qa).

PROPOSED OUTDOOR RESORT
TWENTYNINE PALMS HIGHWAY; APN 0614-121-15
Project No: 544-23355
>-~--------------------< Page 2
Report No: 23-12-620

Sladden
~ Engineering
X
QJ
"Cl 0
~ ~ E 0
N QJ 4..;
Os ~ "" .... u ;::i 8 .s .2 Os 0 :!l .b QJ u "" "' "' P-, - ff) ~ ~ ----·s ·u: ;: 8 ~ "' Os ~ ~
"' ..9 ;::i X QJ
ff) P'.l P'.l µJ ?? ?? Q
10 15 16 1.4 1.1
[I 7 12 14 6.3 1.1
15 17 23 3.2 0.5
tI 9 12 12 4.5 1.0
Completion Notes:

BORELOG
Equipment: Mobile B-61 I Date Drilled: 12/6/2023
>-.
bJ)
..9
0 Elevation: 2,610 Ft. MSL I Boring No:
a! ;3 Description
C, u ..C- ;.a_
p., ~
0 c'.5
} ) Silty Sand (SM); light brown, dry, fine- to coarse-grained (Qa). .... -::: ::
- 2 - :: ::)
::: >:: .... - >: ::,,
:: \ - 4 - .. : r .... :: ::'
BH-3
.... 6 -
- Sand (SP); light brown, dry, medium dense, fine- to coarse-grained (Qa). -
.... 8 -
- -
-10
.... -
- 12-
Sand (SW-SM); light brown, dry, medium dense, fine- to coarse-grained (Qa).
.... -
,.... 14-
,.... 16-
t- 18 -
.... -
- 20-
I- -
Sand (SW); light brown, dry, medium dense, fine- to coarse-grained (Qa).

Sand (SW); light brown, dry, medium dense, fine- to coarse-grained - 22-+'-.:....:....:...:.µ(Q-==-<a)_. ----------------------1 t- -
1- 24-
1- 26-
t- 28-
.... -
.... -
.... 32-
.... - .... 34-
- 36-
- 38-
- -
- 40-
.... 42-
.... 44-
>- 46-
>- 48-
.... -
- 50-
Terminated at -21.5 Feet bgs.

No Bedrock Encountered.

No Groundwater or Seepage Encountered.

PROPOSED OUTDOOR RESORT
TWENTYNINE PALMS HIGHWAY; APN 0614-121-15
.... P_r_oj_e_ct_N_o_: __ 544_-_23_3_5_5 ________ ---,II Pagel Report No: 23-12-620 3

~ BORELOG
Equipment: Mobile B-61 I Date Drilled: 12/6/2023
Stadden Engineering Elevation: 2,595 Ft. MSL I Boring No: BH-4 >,
X bO QJ
"Cl 0 .§ "' ~ ..s 0 't' ,£l § N QJ 'ti "" Description p. .:: I-< p. QJ ;:l 0 s 0 "' .B .f e-:, u ~ u "' "lil ;:l ·S :.E [f) .:: i - - --0--- -- _ -- ___ 1i __ ;;:- -- ------ro-- ------tr.I ----- P-,---~-- s ~ p. --x- .:: p. "' - "' ..9 ;:l X QJ QJ I-<
[f) i:c i:c µJ * * 0 0 l?
I- _1i \ Silty Sand (SM); light brown, dry, fine- to coarse-grained (Qa). :: :=;:

I- 2 - :: :: ! :: I- - :: I- 4 -
tc 7 10 10 5.4 1.0 -
I- 6 - Sand (SW-SM); light brown, dry, medium dense, fine- to coarse-grained I- - (Qa).
- 8 -
I- - - 10- 14 19 23 4.4 0.7 Sand (SW); light brown, dry, medium dense, fine- to coarse-grained I- - I- 12- (Qa). - - 1- 14-
tc I19 25 26 22.5 2.5 - 16- Silty Sand (SM); light brown, dry, very dense, fine- to coarse-grained I- - (Qa).
- 18-
,... - 1- 20
19 31 36 7.1 1.1 121.6 Sand (SW-SM); light brown, dry, very dense, fine - to coarse-grained - - ,... 22 (Qa).
- - ,-. 24- Terminated at -21.5 Feet bgs.

No Bedrock Encountered. I- - - 26- No Groundwater or Seepage Encountered.

I- - - 28-
,... - 1- 30-
- -
1- 32-
- - I- 34-
I- - - 36-
I- - - 38-
I- - 1- 40-
- - I- 42-
I- - ,... 44-
I- - - 46-
I- - -48-
,... - 1- 50-
Completion Notes: PROPOSED OUTDOOR RESORT
TWENTYNINE PALMS HIGHWAY; APN 0614-121-15
Project No: 544-23355
: Page I 4 Report No: 23-12-620

Cg) BORELOG
Equipment: Mobile B-61 I Date Drilled: 12/6/2023
Siadden Engineering Elevation: 2,565 Ft. MSL I Boring No: BH-5 ~
>< bJ)
a., ..s "Cl 0 0 "' ~ .5 0
1S ~ 2 N a., ~
I), ~ 'It >-, u a., Description ;:i 8 .s "' .2 I), a., ....l 0 § e::, a., .;,; u "' "' ;:i "' P.. (j) ' ~ ' .8 ·o-- ..C-- ..c - - ~ .-'I "' :2 :2 "' Ps I), 8 I), ~ "' 0 s a., a., >-, "' ;:i:i >< "" ~ Cl Cl CJ) p::, µ;J 0 l'.) ~ - Silty Sand (SM); light brown, dry, fine- to coarse-grained (Qa).

I- 2 -
~ -
~ 4 -
I13 16 18 6.3 0.9 117.3 ~ 6 - Sand (SW-SM); light brown, dry, medium dense, fine- to coarse-grained I- - (Qa).

I- 8 -
~ -
I- 10 I 9 12 13 12.4 1.3
••••
Silty Sand (SM); light brown, dry, medium dense, fine- to coarse- ~ - ~ 12 vrained (Qa).

I- - ,_ 14- Terminated at -11.5 Feet bgs.

No Bedrock Encountered. I- -
'- 16- No Groundwater or Seepage Encountered.
~ -
1- 18-
~ -
1- 20-
I- -
~ 22-
I- - ~ 24-
I- -
'- 26 -
~ -
1- 28 -
~ -
30-
I- - ,_ 32-
I- -
~ 34-
I- - '- 36-
~ -
1- 38-
~ -
1- 40-
I- -
~ 42-
I- -
~ 44-
I- -
'- 46-
~ -
1- 48 -
~ -
1- 50-
Completion Notes: PROPOSED OUTDOOR RESORT
TWENTYNINE PALMS HIGHWAY; APN 0614-121-15
Project No: 544-23355 l Page [ 5 Report No: 23-12-620

~ BORELOG
Equipment: Mobile B-61 I Date Drilled: 12/6/2023
Sladden Engineering Elevation: 2,540 Ft. MSL I Boring No: BH-6 >- >< bO
"Cl "'0 ,§
§ ,[ .E 0
't N :§ "' 'ti i:: "" .... Description s -~ "' .B p.. "' ...J 0 --~---
!::, --¾-- -----~--1-- u "' ;l ---r;.FJ--- --l',- "' --cl:i ------·s- + --.c;-. p.. ~ ::!l "' ~ ~ ~ .... s 0 p.. ~ ~ "' Ee ;l >< [f) p,:i ~ ?ft. ?ft. p p 0
- - Sand (SW-SM); strong brown, dry, fine- to coarse-grained (Qa). - 2 - :::: 2 0 -:-: - - }: - 4 - ·.· -:-:
tc - 9 10 11 12.7 1.4 - 6 - Ii
Silty Sand (SM); light brown, dry, medium dense, fine- to coarse- - - grained (Qa).
- 8 -
-- -10-
14 17 10 13.6 1.7 118.7 : Silty Sand (SM); light brown, dry, medium dense, fine- to coarse- -- -12 12:rained (Qa).
- - -14- Terminated at -11.5 Feet bgs.

No Bedrock Encountered.
-- - 16- No Groundwater or Seepage Encountered.
-- - 18-
-- -20-
- -
-22-
- -
-24-
-- - 26-
t- - - 28-
t- - t- 30-
- - ,... 32-
- -
,... 34-
- -
- 36-
,... - ,... 38-
,... - ,... 40-
- - - 42- ,... - - 44-
-- - 46-
-- - 48-
-- - 50-
Completion Notes: PROPOSED OUTDOOR RESORT
TWENTYNINE PALMS HIGHWAY; APN 0614-121-15
Project No: 544-23355 l Page I 6 Report No: 23-12-620

(§) BORE LOG
Equipment: Mobile B-61 I Date Drilled: 12/6/2023
Sladden Engineering Elevation: 2,595ft. MSL I Boring No: BH-7 :>-. X bO OJ 0 '1J 0 0 ZJ JI, E 0 ~ ,:;:;-- N OJ ::§ ~ p., "' u <l) Description ;:j ~ ;..; p., <l) ....i 0 E 0 U) .8 .f I:::!, u <l) u "' .in ;:j U) p... V) ~ :E ---~ ~-- :S ;;: .,.. "' ~-- •• - .:,. E 0 ~ p., p., "' "' 55 X OJ <l) V) i:o µ:J cf x 0 0 0 CJ
- - Sand (SW-SM); strong brown, dry, fine- to coarse-grained (Qa).

I- 2
- -
..... 4 -
I I- - 3 3 4 13.l 1.6 - 6 - Silty Sand (SM); strong brown, dry, loose, fine- to coarse-grained (Qa).

I- -
I- 8 -
- -
I- 10 -
13 24 25 No Recovery.
- -
1- 12
I- -
- 14-
Terminated at~ 11.5 Feet bgs.

No Bedrock Encountered. I- -
- 16 No Groundwater or Seepage Encountered.
- - - 18-
- - 1- 20-
--
- 22-
I- -
- 24-
I- -
1- 26-
- -
1- 28-
- - 1- 30 -
- -
- 32-
- -
- 34-
- -
- 36-
- -
- 38-
- -
- 40-
- - - 42-
- -
- 44-
- -
- 46-
- -
- 48-
- - ,- 50-
Completion Notes: PROPOSED OUTDOOR RESORT
TWENTYNINE PALMS HIGHWAY; APN 0614-121-15
Project No: 544-23355 I Page I 7 Report No: 23-12-620

~ BORELOG
Equipment: Mobile B-61 I Date Drilled: 12/7/2023
Sladden Engineering Elevation: 2,580 Ft. MSL I Boring No: BH-8 >,
X bO llJ
'"O 0 ,§ "' "E. .s 0 ~ ::§ § N
,.. llJ 'ti i:: ... P.. llJ Description llJ ...:I 0 s .Sl "' ~ >. ~ u --$--- U- "' "' ;:j ---err----,:::---- --___ ;a_ -:s- - ----"-a--- ~~- -~--~ -,----- p.. ---- ~ "' "' p.. s ~ p.. ~ ~ i:: P.. "' "' ..Q ;:j X QJ QJ ... IXl IXl >1l #- "" r.f) 0 Cl Cl c., t- - Sand (SW-SM); strong brown, dry, fine- to coarse-grained (Qa). - 2 -
t- - t- 4 -
- - 12 14 17 8.2 1.0 115.1 t- 6 - Sand (SW-SM); light brown, dry, medium dense, fine- to coarse-grained t- - (Qa).
t- 8 -
t- -
tc - 10 8 12 19 4.9 0.8 Sand (SW); light brown, dry, dense, fine- to coarse-grained (Qa). t- - t- 12- - - t- 14-
t12 27 30 10.1 0.8 112.3 t- 16- Sand (SW-SM); light brown, dry, dense, fine- to coarse-grained (Qa). t- - - 18-
\ I- -
tc 1- 20-
11 15 16 5.7 0.9 Sand (SW-SM); light brown, dry, dense, fine- to coarse-grained (Qa). t- - 1- 22 - - t- 24- Terminated at -21.5 Feet bgs.

No Bedrock Encountered. I- - t- 26- No Groundwater or Seepage Encountered.

I- - -28-
t- - t- 30-
t- - t- 32-
- - t- 34-
t- - t- 36-
t- - - 38-
- - t- 40-
- -
- 42-
- -
- 44-
- - - 46-
- - - 48-
- -
- 50-
Completion Notes: PROPOSED OUTDOOR RESORT
TWENTYNINE PALMS HIGHWAY; APN 0614-121-15
Project No: 544-23355 I Page I 8 Report No: 23-12-620

Sla.dden Engineering
><
(l)
"d 0 VJ (l) .s 0
7:: 0. N (l)
h "<c
;:i '" s .s VJ 0 .2 (l) u ~-- VJ ;:i -~--- 0. h .8 0
s ;!: '3 ro ~ 21 ..9 Ps ro >< C/l P'.l P'.l µ.) ?f- ?foc 3 6 10 18.7 1.8

BORE LOG
Equipment: Mobile B-61 I Date Drilled: 12/7/2023
Elevation: 2,565 Ft. MSL j Boring No: BH-9
Description
::: >>: Sand (SW-SM); strong brown, dry, fine- to coarse-grained (Qa). I--:-:::::: I:.·.· - 2 -I / ,_ + ... - 4 - ·-·::_. - 1.· ,:.·
I
< Silty Sand (SM); strong brown, dry, medium dense, fine- to coarse- - 6 - '::
: \ grained (Qa).
,_ 8 -1 , ••• ::' - -1,> -10+"-"-'"+--------------------------1 15 19 28 8.4 1.1 114.7 ,_ _ Sand (SW-SM); light brown, dry, dense, fine- to coarse-grained (Qa). [I 12 15 17 6.6 1.1
20 32 37 6.6 1.1 118.1
Completion Notes:
-12-
1- 14 -
1- 16 - Sand (SW-SM); light brown, dry, dense, fine- to coarse-grained (Qa). - 18-
I- -
- 20-
I- - Sand (SW-SM); light brown, dry, dense, fine- to coarse-grained (Qa). -22-+-'__;_:_-'-'-1-----------------------------l
1- 24-
1- 26-
- 28-
I- -
- 30
- -
- 32-
- 34-
- 36-
- - - 38-
- - - 40-
- - 1- 42-
,_ 44-
1- 46-
,_ -
- 50-
Terminated at -21.5 Feet bgs.

No Bedrock Encountered.

No Groundwater or Seepage Encountered.

PROPOSED OUTDOOR RESORT
TWENTYNINE PALMS HIGHWAY; APN 0614-121-15
~P_r--'oj_ec_t_N_o_: __ 5_44_-_2_33_5_5 __________ -'-'-tlj Pagel Report No: 23-12-620 9

Sladden
~ Engineering
>< OJ
'"O 0
~ ~ Ei 0
N p.. OJ 't:l "" i:,: .... p..
0 s .s "' B ~ ~ u "' "' ;; ·S U) i:,: .s ..... ·~ p.. .. ~ ---«:I-- s .;:,(_ ..
p.. ·~::s -::E·
"' .9 "3 >< OJ
U) P'.l P'.l ~ # # Cl
5 6 8 3.3 0.8
7 8 10 3.7 0.8
17 20 25 6.0 1.0 115.0
17 17 17 10.5 1.4
Completion Notes:
>.
bO
.9
0 ~ 3 OJ
OJ
c::, u
:E . .-:5~ ·-··.P.. p.. "' OJ .... Cl Cl
2 4
6 8
10 12
14 16
18 20
22 24
26 28
30 32
34 36
38 40
42 44
46 48
50 BORELOG
Equipment: Mobile B-61 Date Drilled: 12/7/2023
Elevation: 2,535 Ft. MSL Boring No: BH-10
Description
Sand (SW-SM); strong brown, dry, fine- to coarse-grained (Qa).

Sand (SW); light brown, dry, loose, fine- to coarse-grained (Qa).

Sand (SW); light brown, dry, medium dense, fine- to coarse-grained (Qa).

Sand (SW-SM); light brown, dry, medium dense, fine- to coarse-grained (Qa).

Sand (SW-SM); light brown, dry, dense, fine- to coarse-grained (Qa).

Terminated at -21.5 Feet bgs.

No Bedrock Encountered.

No Groundwater or Seepage Encountered.

PROPOSED OUTDOOR RESORT
TWENTYNINE PALMS HlGHWAY; APN 0614-121-15
Project No: 544--23355
t--R~--N---2-3--12---62-0-----------1 Page 10 eport o:

(§) BORELOG
Equipment: Mobile B-61 I Date Drilled: 12/7/2023
Siadden Engineerh1g Elevation: 2,555 Ft. MSL I Boring No: BH-11 >. >< bO
"' 0 "CJ 0 0 '" "' Ji 0 :;:-- ,8 -;;: N "' ~ P. i:: "" H u "' ;:i Description ;::i s .8 P.. 0 .s Vl "' ;;:. I:::, u ~ u ... "' '" ;::i Vl t/l i:: :E- - - - i:: .. •o---- .-;; P.. £ ;:: 1 "' ~ ::;s Vl P.. s P.. i:: P.. "' "' ..s >< "' "' H t/l r:o r:o µJ ?f?- ?f?- Cl Cl CJ
'- - Sand (SW-SM); strong brown, dry, fine- to coarse-grained (Qa). '- 2 -
L- -
'- 4 -
[I L- - 9 10 11 9.3 0.3 '- 6 - Sand (SW-SM); light brown, dry, medium dense, fine- to coarse-grained L-
(Qa).
- 8 -
- - Terminated at -6.5 Feet bgs.
- 10- No Bedrock Encountered.
- - No Groundwater or Seepage Encountered.
- 12-
- -
- 14-
- -
- 16-
- -
- 18-
L... -
'""20-
L... -
L- 22-
L- -
'- 24-
L- -
'- 26 -
'- -
'- 28 -
L- -
'"" 30
L- -
'""32-
L- -
L- 34-
L- -
- 36-
'- -
1- 38-
L- -
'""40-
I- - '""42-
I- - L- 44-
L- -
1- 46-
L- -
1- 48-
L- -
'"" 50 -
Completion Notes: PROPOSED OUTDOOR RESORT
TWENTYNINE PALMS HIGHWAY; APN 0614-121-15
Project No: 544-23355
~ Page] 11 Report No: 23-12-620

(§) BORELOG
Equipment: Mobile B-61 I Date Drilled: 12/6/2023
Siadden IEngineer-ing Elevation: 2,580 Ft. MSL I Boring No: SW-1 >-. >< bl)
0)
-0 "3 0 U) 0) E 0 £ -::: "' ~ ~ Os h "" 0) u 0) j Description ;; s ii 0.. (lJ 0 .s U) .f c :E (lJ u "' U) ;; U)
Os Cf) h
~ -·o- £ :s: ~ "' ~ U) 0.. s 0 0.. h 0.. "' "' ii:i ;; >< (lJ (lJ ,.., Cf) P'.l w cJ2. cJ2. a a l'.) <-:- - -
- 2 -
Silty Sand (SM); light brown, dry, fine- to coarse-grained (Qa). - - - 4 -
-
- 6 -
- - Terminated at -5.0 Feet bgs.
1-- 8 - No Bedrock Encountered.
- - No Groundwater or Seepage Encountered.
f-- 10-
1-- -
- 12-
1-- -
1-- 14-
- -
1-- 16-
- -
1-- 18-
1-- -
- 20-
1-- -
- 22-
t- -
>- 24-
- -
>- 26-
- -
t- 28-
>- -
- 30-
- - - 32-
- -
- 34-
- -
- 36-
- -
- 38-
- -
- 40-
- -
-42-
- - 1-- 44-
- -
1-- 46-
- -
1-- 48-
1-- -
- 50-
Completion Notes: PROPOSED OUTDOOR RESORT
TWENTYNINE PALMS HIGHWAY; APN 0614-121-15
Project No: 544-23355 I Page I 12 Report No: 23-12-620

(§) BORELOG
Equipment: Mobile B-61 I Date Drilled: 12/7/2023
Sladden Engineering Elevation: 2,570Ft. MSL I Boring No: SW-2 ~
X bJ)
CJ
"1} .s 0 0 V) CJ ,E 0 :§ N ~ ~ 1:: P.. r:: Set 2:: u CJ Description :, s .2 Os CJ ..J 0 .s V) >, f:::, u 2- -- u "' V) :, V)
ell r:: -;E .s ·s ."!:: --- Os ii ~ '5 "' ::;2 ::;2 V) Os s Os r:: Os "' "' 0 X CJ CJ Cf) Eo ll'.:l ~ cf. c'.3 * Cl Cl
>- -
- 2
,... Silty Sand (SM); light brown, dry, fine- to coarse-grained (Qa). >- 4
- I
>- 6 -
- - Terminated at -5.0 Feet bgs.
>- 8 - No Bedrock Encountered.
>- - No Groundwater or Seepage Encountered.
- 10-
>- -
- 12-
- -
>- 14 -
- -
>- 16 -
.... -
- 18-
,_ -
- 20-
,_ -
,- 22-
- -
,- 24-
- -
,- 26-
I- -
- 28-
I- -
30-
- -
- 32-
- -
.... 34-
- -
- 36-
.... -
- 38-
- -
- 40-
>- - >- 42-
- -
>- 44-
- -
>- 46-
.... -
- 48-
>- - - 50-
Completion Notes: PROPOSED OUTDOOR RESORT
TWENTYNINE PALMS HIGHWAY; APN 0614-121-15
Project No: 544-23355 I Page I 13 Report No: 23-12-620

(§) BORELOG
Equipment: Mobile B-61 I Date Drilled: 12/7/2023
Sladden Engineering Elevation: 2,605Ft. MSL I Boring No: SW-3 X
(1)
~
"Cl 0 .§ U) ,t ..s 0 ~ :§ § N (1) .. 'tJ (1) Description .§ .... 0.. (1) ,...:i 0 s U) .8 >, f:::!, :E ..!:l u "' U) ;; V) -~ -i- .E ~~----- - $-- -~- ~--- ;§- - 1-- -0- - - -i:,:, -~--- s 0.. ~ ~ i:: 0.. "' "' ,Q ;; X (1) (1) .... V) i:o i:o ~ * * 0 0 c.? --
- 2 -
- -
- 4 -
.... - Silty Sand (SM); light brown, dry, fine- to coarse-grained (Qa) . - 6 -
.... -
- 8 -
,- -
.... 10
- -
,- 12- Terminated at -10.0 Feet bgs.

No Bedrock Encountered.
- -
,- 14- No Groundwater or Seepage Encountered.

I- -
- 16-
,- - I- 18-
,- - 1- 20-
- - ,- 22-
I- -
,- 24-
I- -
- 26-
,- - ,- 28-
,- - ,- 30-
- - ,- 32-
.... - ,- 34-
I- -
- 36-
,- - '""38-
,- - ,- 40-
- - ,- 42-
.... - ,- 44-
I- -
-46-
,- - ,- 48-
,- - 1- 50-
Completion Notes: PROPOSED OUTDOOR RESORT
TWENTYNINE PALMS HIGHWAY; APN 0614-121-15
Project No: 544-23355
: Page I 14 Report No: 23-12-620

~ BORELOG
Equipment: Mobile B-61 I Date Drilled: 12/7/2023
Stadden Engineering Elevation: 2,530 Ft. MSL I Boring No: SW-4 >,
>< bO 0) ..Q "Cl 0 0
"' ,[ .5 0
~ ~ :§ N 0) 'tJ i:: .,. Description ;; .... p.. 0) ...:i 0 s -~ "' .8 -.f- ~ u --~ u -- - ----· "" ;; --•S- --- ··{;(}·- -_-;a.__ i::-- - ·:!§l ---£- ------- p.. ~ "' "' p.. s 0 ~ p.. ::;;: ::;;: ~ p.. "' "' i:ii ;; >< 0) .... er, ea ~ cf. cf. Cl Cl l? t- -
- 2 -
t- - Silty Sand (SM); light brown, dry, fine- to coarse-grained (Qa). t- 4 -
-
t- 6 -
- - Terminated at -5.0 Feet bgs.
t- 8 - No Bedrock Encountered.
t- - No Groundwater or Seepage Encountered.
- 10-
t- - t- 12-
t- - t- 14-
- - t- 16-
t- - - 18-
I- - -20-
I- -
t- 22-
t- - t- 24-
- - t- 26-
I- - t- 28-
t- -
- 30-
t- -
t- 32-
I- - t- 34-
- - 1- 36-
t- - - 38-
t- - - 40-
I- - t- 42-
- -
t- 44-
- - t- 46-
t- - -48-
t- - - 50-
Completion Notes: PROPOSED OUTDOOR RESORT
TWENfYNINE PALMS HIGHWAY; APN 0614-121-15
Project No: 544-23355
: Page I 15 Report No: 23-12-620

(§) BORE LOG
Equipment: Mobile B-61 I Date Drilled: 12/7/2023
Sladden Engineeiring Elevation: 2,570 Ft. MSL I Boring No: SW-5 ~
>< bD Q.) ..9 "O 0 0
~ ~ E 0 '.µ' N Q.) :§ ~
P-., ""' u Q.) Description ;:l h H P-., Q.) ....J 0 E 0 "' .2 ~ c:, u OJ u "' ·r;; ;; P.. r.n h h .~-- • '5 <E ~ "' ~ 0 "' P-., E ::'=: P-., ;:;: h P-., "' "' 0 ;:l >< Q.) Q.) r.n r.o i:o 1-Il "c2- "c2- Q Q c'.5
- -
- 2 -
Silty Sand (SM); light brown, dry, fine- to coarse-grained (Qa). - - - 4 -
-
- 6 -
- - Terminated at -5.0 Feet bgs.
- 8 - No Bedrock Encountered.
- - No Groundwater or Seepage Encountered.
f-- 10-
- -
f-- 12-
f-- -
- 14-
f-- -
- 16-
- - f-- 18-
- -
1- 20-
-
1- 22-
I-
- 24
I- -
- 26-
,- - 1- 28-
- -
- 30-
- -
- 32-
- -
- 34-
- -
- 36-
- -
- 38-
- - - 40-
c""" -
- 42-
f-- -
-44-
I- -
f-- 46-
- -
1- 48-
- -
,- 50-
Completion Notes: PROPOSED OUTDOOR RESORT
TWENTYNINE PALMS HIGHWAY; APN 0614-121-15
Project No: 544-23355 l Page I 16 Report No: 23-12-620

(§) BORE LOG
Equipment: Mobile B-61 I Date Drilled: 12/7/2023
Siadden IEngineeiring Elevation: 2,545 Ft. MSL I Boring No: SW-6 >.,
>< bO <l) ..9 "O 0 0 "' .!\I J:i 0 ~ ,£i ~ N (I) ~
P-; i:: "" H u (I) ;J Description ::, Ei 0 "' .B P-; <l/ 0 .f f::.. u ~-- u "' ·,:; ::, .~ -- ' :E P-; lf} i:: .s 0 --- i:S ;s ~ "' :::s :::s "' P-; Ei P-; i:: P-; "' "' ..9 ::, >< <l) <l/ H lf} P'.l P'.l >-'l ?ft. x p p C) 0
- -
,-.. 2 -
,-.. - Silty Sand (SM); light brown, dry, fine- to coarse-grained (Qa). - 4 -
,-..
- 6 -
- Terminated at -5.0 Feet bgs.
- 8 - No Bedrock Encountered.
- - No Groundwater or Seepage Encountered.
,-.. 10-
,-.. -
- 12-
f- -
- 14-
,-.. - 1- 16-
- -
f- 18-
- -
- 20-
f- -
- 22-
,-.. -
- 24-
- -
,-.. 26-
- -
,-.. 28-
- -
30-
- -
- 32-
- -
- 34-
- -
- 36-
- -
- 38-
- - - 40-
- -
- 42-
- -
- 44-
- -
- 46-
- - - 48-
- -
- 50-
Completion Notes: PROPOSED OUTDOOR RESORT
TWENTYNINE PALMS HIGHWAY; APN 0614-121-15
Project No: 544-23355 I Page I 17 Report No: 23-12-620

~ BORE LOG
Equipment: Mobile B-61 I Date Drilled: 12/7/2023
Sladden Engineering Elevation: 2,525 Ft. MSL I Boring No: SW-7 >, X bO ,.,
"tl 0 ~ i "E. .E 0 Z' :§ N ,., 'ti
.§ "' .... 0.. ,., Description 8 .8 ,., ,_J 0 ~1 ¾- ~~--- u - ---Qr--1- --·-·t;·· --~-----t'G--- ----§- -- ___ -----UJ ___ -- . :z--~---- -- ------- ----- P-. Cl) ·s ·&1 ,5 ~ =!I ~ 0.. 8 ~ ~ 0.. "' "' ..s ;:I ,., .... Cl) ~ ~ ~ cf2. ?fl. p p C) _._
t-- - •.
1- 2 -1·.
- -1:-:-
t-- 4 -
::
:::: Silty Sand (SM); light brown, dry, fine- to coarse-grained (Qa). t-- 6 - ::::
t-- - ::: - 8 -< t-- -
t-- 10 > t-- - t-- 12- Terminated at - 10.0 Feet bgs.

No Bedrock Encountered.
- - t-- 14- No Groundwater or Seepage Encountered.
t-- - - 16-
t-- - - 18-
I- - I- 20-
- -
t-- 22-
- - 1- 24-
I- - - 26-
I- - - 28-
I- - t-- 30-
- -
t-- 32-
- -
t-- 34-
t-- - - 36-
t-- - - 38-
t-- - t-- 40-
- - t-- 42-
- -
t-- 44-
t-- - -46-
t-- - - 48-
t-- - t-- 50-
Completion Notes: PROPOSED OUTDOOR RESORT
TWEN1YN1NE PALMS HIGHWAY; APN0614-121-15
Project No: 544-23355
: Page I 18 Report No: 23-12-620

APPENDIXB

LABORATORY TESTING
Sladden Engineering
www.SladdenEngineering.com Page 1040 of 1452

APPENDIXB

LABORATORY TESTING
Representative bulk soil samples were obtained-in the field and returned to our laboratory-for additional observations and testing. Laboratory testing was generally performed in two phases. The first phase consisted of testing in order to determine the compaction of the existing natural soil and the general engineering classifications of the soils underlying the site. This testing was performed in order to estimate the engineering characteristics of the soil and to serve as a basis for selecting samples for the second phase of testing. The second phase consisted of soil mechanics testing. This testing including consolidation, shear strength and expansion testing was performed in order to provide a means of developing specific design recommendations based on the mechanical properties of the soil.

CLASSIFICATION AND COMP ACTION TESTING
Maximum Density-Optimum Moisture Determinations: Representative soil types were selected for maximum density determinations. This testing was performed in accordance with the ASTM Standard D1557, Test Method A. Graphic representations of the results of this testing are presented in this appendix. The maximum densities are compared to the field densities of the soil in order to determine the existing relative compaction to the soil.

Classification Testing: Soil samples were selected for classification testing. This testing consists of mechanical grain size analyses. This provides information for developing classifications for the soil in accordance with the Unified Soil Classification System which is presented in the preceding appendix.

This classification system categorizes the soil into groups having similar engineering characteristics. The results of this testing is very useful in detecting variations in the soil and in selecting samples for further testing.

SOIL MECHANIC'S TESTING
Expansion Testing: Two (2) bulk samples were selected for Expansion testing. Expansion testing was performed in accordance with the UBC Standard 18-2. This testing consists of remolding 4-inch diameter by 1-inch thick test specimens to a moisture content and dry density corresponding to approximately 50 percent saturation. The samples are subjected to a surcharge of 144 pounds per square foot and allowed to reach equilibrium. At that point the specimens are inundated with distilled water. The linear expansion is then measured until complete.

Direct Shear Testing: Two (2) bulk samples were selected for Direct Shear testing. This test measures the shear strength of the soil under various normal pressures and is used to develop parameters for foundation design and lateral design. Tests were performed using a recompacted test specimen that was saturated prior to tests. Tests were performed using a strain controlled test apparatus with normal pressures ranging from 800 to 2300 pounds per square foot.

Corrosion Series Testing: The soluble sulfate concentrations of the surface soil were determined in accordance with California Test Method Number (CA) 417. The pH and Minimum Resistivity were determined in accordance with CA 643. The soluble chloride concentrations were determined in accordance with CA 422.

Sladden Engineering
www.SladdenEngineering.com Page 1041 of 1452
~ Sladden Engineering
450 Egan Avenue, Beaumont CA 92223 (951) 845-7743 Fax (951) 845-8863 Project Number:

Project Name:

Lab ID Number:

Sample Location:

Description:

Maximum Density:

Optimum Moisture:

Maximum Density/Optimum Moisture
ASTM D698/Dl557
544-23355
Twentynine Palms Highway
LN6-23487
BH-1 Bulk 1 @ 0-5'
Red Brown Clayey Sand (SC)
133 pcf
7%
Corrected for Oversize (ASTM D4718)
Sieve Size % Retained
145
140
135
130
...
c- 125 i=..
,e:
...
~
5 ~ 120
t-
~
115
3/4"
3/8"
#4
\ '- '
\ " '-
\ " "
\ \ "
" " "
' - ~
I
,
' .I'
-i
l
!
'
:
i
l
" " " " " "
...
-

5.5 " " <----- Zero Air Voids Lines,
" " \. \. sg ==2.65, 2.70, 2.75
" "
'\. " '-
'- " " " ' ' ' \. I\. '- '\. ' '\.
" '\.
' '\. '\.
• '\. '- " ' '\. \.
'\. ' '\.
'\. '\.
'\. '' '\. '
'\.
"- '-' "\
'- "- "-
' ' ' 1, ' ' "-
December 18, 2023
ASTMD-1557 A
Rammer Type: Machine
'-, ....... '
110
105
100
0 :
' !
!
j
!
'
5 15
Moisture Content, %
Beaumont • Indio • Buena Park
....... " ' ,, ' '-
' "'' ' " ....... ' .......
' l's. "
' ' ' 1," " '- ' ...... "' 1"'-
20 25

~ Sladden Engineering
450 Egan Avenue, Beaumont CA 92223 (951) 845-7743 Fax (951) 845-8863 Project Number:

Project Name:

Lab ID Number:

Sample Location:

Description:

Maximum Density:

Optimum Moisture:

Maximum Density/Optimum Moisture
ASTM D698/Dl557
544-23355
Twentynine Palms Highway
LN6-23487
BH-6 Bulk 2 @ 0-5'
Light Brown Sand w/Silt (SW-SM)
131 pcf
8%
Corrected for Oversize (ASTM D4718)
Sieve Size % Retained
145
140
135
130
...

C,I 125 =-
i
~
5 A 120
t'
A
115
3/4"
3/8"
#4
! '\ '\ ' \ \ '\
! '\ '\
l '\ '\
! '\ '\
! '\
! \
\
~
,r
!
' ;
l
!
!
" '\
"\
\
'\
'\
'\
~

5.4 " '\
'\ <----- Zero Air Voids Lines, '\
'\ '\. sg =2.65, 2.70, 2.75
\ '\
'\ '\. '
"\ "\
'\. ...... ' ' ' '\. I'\. ... '\. ' '\.
' '\. '\. ~ '\. '\.
'" '\. I\."\
"\ '\. '\.

I\. ' '\.
'\. '\.
"\ '\.
'\. '\. '
'\. '\.
'\. ' '\ ' '\. '\.
'\. '\..
" '\. '" '\.. '\..

December 18, 2023
ASTMD-1557 A
Rammer Type: Machine
! " '\. '
110
105
100
0 !
l
l
!
!
!
5 15
Moisture Content, %
Beaumont • Indio • Buena Park
,, "\. " '\.. '" '\.. '\..
" '\.. '\.. ' '\.
' '
'
20 I'\.
'" " ' ' ' ' ,, ' " "- ·""
25

~ Sladden Engineering
450 Egan Avenue, Beaumont, CA 92223 (951) 845-7743 Fax (951) 845-8863 Expansion Index
ASTMD 4829
Job Number: 544-23355
Job Name: Twentynine Palms Highway
Lab ID Number: LN6-23487
Sample ID: BH-1 Bulk 1@ 0-5'
Soil Description: Red Brown Clayey Sand (SC)
Wt of Soil + Ring: 605.5
Weight of Ring: 194.7
Wt of Wet Soil: 410.8
Percent Moisture: 6.5%
Sample Height, in 0.95
Wet Density, pcf: 131.5
Dry Denstiy, pcf: 123.4
I% Saturation: 48.1
Expansion Rack # 2
Date/Time
Initial Reading
Final Reading
Expansion Index
(Final - Initial) x 1000
12/12/2023 I

0.0000

0.0000
10:40 AM
0 Beaumont • Indio • Buena Park
December 18, 2023

~ Sladden Engineering
450 Egan Avenue, Beaumont, CA 92223 (951) 845-7743 Fax (951) 845-8863 ~pausion lnde-xASTM D 4829
Job Number: 544-23355
Job Name: Twentynine Palms Highway
Lab ID Number: LN6-23487
Sample ID: BH-6 Bulk 2@ 0-5'
Soil Description: Light Brown Sand w/Silt (SW-SM)
Wt of Soil + Ring: 592.9
Weight of Ring: 188.5
Wt of Wet Soil: 404.4
Percent Moisture: 7.3%
Sample Height, in 0.95
Wet Density, pcf: 129.4
Dry Denstiy, pcf: 120.6
I 0/o Saturation: 49.6
Expansion Rack # 2
Date/Time 12/14/2023 I 2:20PM
Initial Reading 0.0000
Final Reading 0.0000
Expansion Index 0
(Final - Initial) x 1000
Beaumont • Indio • Buena Park
December 18, 2023

Sladde E ,. "' g1neer1ng
450 Egan Avenue, Beaumont, CA 92223 (951) 845-7743 Fax ) 845-8863 Direct Shear ASTM D 3080-04
(modified for unconsolidated condition)
Job Number:

Job Name
Lab ID No.

Sample ID
544-23355
Twentynine Palms Highway
LN6-23487
BH-1 Bulk 1 @ 0-5'
Classification Red Brown Clayey Sand (SC)
Sample Type Remolded @ 90% of Maximum Density
Test Results 1 2
Moisture Content, % 11.9 11.9
Saturation, % 77.4 77.4
Normal Stress, kps 0.739 1.479
Peak Stress, kps 0.807 1.417
3 11.9

77.4 2.958

2.616
~ Peak Stress -Linear (Peak Stress) I

6.0 December 18, 2023
Initial Dry Density: 119.2 pcf
Initial Mosture Content: 7.4 %
Peak Friction Angle (0): 36°
Cohesion (c): 350 psf
4 Average

11.9 11.9

77.4 77.4

5.916

4.556
l---+---+------+-,----+-------j-+-----+----+-----+-----+-f----+--+----t--+~-+--~1----------~--+-f----+--+---l

5.0 j4.0
r/;'
"" f 3.0 ,,..,
00 ...
...
~ J 2.0
lf)

1.0 0.0
0 l 2 3 4 5 6
No:rmal Stress, kps
Beaumont • Indio e Buena Park

~ Sladden Engineering
450 Egan Avenue, Beaumont, CA 92223 (951) 845-7743 Fax (951) 845-8863 Direct Shear ASTM D 3080-04
(modified for unconsolidated condition)
Job Number:

Job Name
LabID No.

Sample ID
544-23355
Twentynine Palms Highway
LN6-23487
BH-6 Bulk 2 @ 0-5'
Classification Light Brown Sand w/Silt (SW-SM)
Sample Type Remolded@ 90% of Maximum Density
Test Results 1 2
Moisture Content, % 12.6 12.6
Saturation,% 77.9 77.9
Normal Stress, kps 0.739 1.479
Peak Stress, kps 0.937 1.744
3 12.6

77.9 2.958

3.074
• Peak Stress -Linear (Peak Stress) I
December 18, 2023
Initial Dry Density: 117.3 pcf
Initial Mosture Content: 8.4 %
Peak Friction Angle (0): 39°
Cohesion ( c ): 490 psf
4 Average

12.6 12.6

77.9 77.9

5.916

5.188

6.0 ,---,..---,-----,---,----,.-,---,----,.--,.---,---,----,.----,,---,---....--.---,---,---,----,-,----,----.----.

5.0 0.0 _......._ ___ __.._ _ __._..___.____......____..___._ ..__..____..__ _______________ ,-----....__ ___ ..... 0 1 2 3 4 5 6
Normal Stress, kps
Beaumont • Indio • Buena Park

~ Sladden Engineering
450 Egan Avenue, Beaumont, CA 92223 (951) 845-77 43 Fax (951) 845-8863 Gradation
ASTM Cl 17 & Cl36
Project Number: 544-23355 December 18, 2023
Project Name:

Lab ID Number:

Sample ID:
bl}
.s
00 00
P-. "'
~
100.0

90.0 80.0

70.0 60.0

50.0 40.0

30.0 20.0

10.0 0.0
100.000
Twentynine Palms Highway
LN6-23487
BH-1 Bulk 1@ 0-5' Soil Classification: SC
Sieve
Size, in
2"
1 1/2"
l"
3/4"
1/2"
3/8"
#4
#8
#16
#30
#50
#100
#200
. .

10.000
~
\
\.
'
Sieve
Size, mm

50.8 38.1

25.4 19.1

12.7 9.53

4.75 2.36

1.18 0.60

0.30 0.15

0.075
I\
\
\.
'"\
~
I\.
r\.
',
'" ..........
~

1.000 0.100
Sieve Size, mm
Percent
Passing
100.0
100.0

99.8 99.7

99.4 98.8

94.4 80.0

59.8 41.8

28.3 19.9

14.6 Beaumont • Indio • Buena Park

0.010 0.001
+

---------1
I
~ Sladden Engineering
450 Egan Avenue, Beaumont, CA 92223 (951) 845-7743 Fax (951) 845-8863 Gradation
ASTM Cl 17 & C136
Project Number: 544-23355 December 18, 2023
Project Name:

Lab ID Number:

Sample ID:
-~ "' gj
~
~
100.0

90.0 80.0

70.0 60.0

50.0 40.0

30.0 20.0

10.0 0.0
100.000
.

Twentynine Palms Highway
LN6-23487
BH-6 Bulk 2 @ 0-5' Soil Classification: SW-SM
Sieve
Size, in
2"
1 1/2"
l"
3/4"
1/2"
3/8"
#4
#8
#16
#30
#50
#100
#200
~
T
T ~
i,...

10.000
'\
\
' \
~
Sieve
Size, mm

50.8 38.1

25.4 19.1

12.7 9.53

4.75 2.36

1.18 0.60

0.30 0.15

0.075
\
\
\.
~
~
' '
1'-"'
"~
"r--,.. ......

1.000 0.100
Sieve Size, mm
Percent
Passing
100.0
100.0
100.0

99.8 99.4

98.9 94.5

72.8 50.6

34.5 23.0

15.6 10.9
Beaumont • Indio • Buena Park

0.010 0.001
f

--------.,
'
~ Sladden Engineering
450 Egan Avenue, Beaumont, CA 92223 (951) 845-7743 Fax (951) 845-8863 Gradation
ASTM Cl 17 & Cl36
Project Number: 544-23355 December 18, 2023
Project Name:

Lab ID Number:

Sample ID:
100
90 80
70 60
bl)
.s
rn
rn 50
ti:!
Po.
t?. 40
30 20
10 0
100.000
Twentynine Palms Highway
LN6-23487
BH-1 S-3 @ 10' Soil Classification: SM
Sieve Sieve
Size, in Size, mm
l" 25.4
3/4" 19.1
1/2" 12.7
3/8" 9.53
#4 4.75
#8 2.36
#16 1.18
#30 0.60
#50 0.30
#100 0.15
#200 0.074
. .
. . "" [\
I\.
" I\
\
~
r..

I\
'\
' .
\
'I\
~
" ~

10.000 1.000 0.100
Sieve Size, mm
Beaumont • Indio • Buena Park
Percent
Passing
100.0
100.0
100.0
100.0

97.4 84.6

67.8 52.4

36.7 22.4

12.6 0.010 0.001

~ Sladden Engineering
450 Egan Avenue, Beaumont, CA 92223 (951) 845-7743 Fax (951) 845-8863 Gradation
ASTM Cl 17 & Cl36
Project Number: 544-23355 December 18, 2023
Project Name:

Lab ID Number:

Sample ID:
00 C:
·;;;
r/l
~
~
~
100
90 80
70 60
50 40
30 20
10 0
100.000
Twentynine Palms Highway
LN6-23487
BH-3 R-1 @5' Soil Classification: SP
Sieve
Size, in
l"
3/4"
1/2"
3/8"
#4
#8
#16
#30
#50
#100
#200
~ ~
~ ~ ,...

10.000
Sieve
Size, mm

25.4 19.1

12.7 9.53

4.75 2.36

1.18 0.60

0.30 0.15

0.074
" f\.
"'I
I
\
\
\
\
►
\
[\
'\
' ~
le

1.000 0.100
Sieve Size, mm
Beaumont • Indio • Buena Park
Percent
Passing
100.0
100.0
100.0
100.0

99.7 89.5

62.4 36.9

17.7 6.6

1.4 0.010 0.001

~ Sladden Engineering
450 Egan Avenue, Beaumont, CA 92223 (951) 845-7743 Fax (951) 845-8863 Gradation
ASTM Cll7 & C136
......, ______ -1
I
Project Number: 544-23355 December 18, 2023
Project Name:

Lab ID Number:

Sample ID:
bl)
.s
rJl
rJl
ro
p..
~
100
90 80
70 60
50 40
30 20
IO
0 100.000
Twentynine Palms Highway
LN6-23487
BH-4 S-3@ 15' Soil Classification: SM
Sieve
Size, in
l"
3/4"
1/2"
3/8"
#4
#8
#16
#30
#50
#100
#200
~ ~
. - "'t--i..

10.000
Sieve
Size, mm

25.4 19.1

12.7 9.53

4.75 2.36

1.18 0.60

0.30 0.15

0.074
I\
\
I". r-..
'\
~ ~~
~t
f\
\~
'\
\.
'-
"~ ~

1.000 0.100
Sieve Size, mm
Beaumont • Indio • Buena Park
Percent
Passing
100.0
100.0
100.0

99.2 95.8

81.0 67.3

56.2 45.7

33.9 22.5

0.010 0.001

--------~ I
~ Sladden Engineering
450 Egan Avenue, Beaumont, CA 92223 (951) 845-7743 Fax (951) 845-8863 Gradation
ASTM Cl 17 & Cl36
Project Number: 544-23355 December 18, 2023
Project Name:

Lab ID Number:

Sample ID:

OJ)
i::
·;;.;
ell
ce
~
~
100
90 80
70 60
50 40
30 20
10 0
100.000
Twentynine Palms Highway
LN6-23487
BH-8 S-4@20 Soil Classification: SW-SM
Sieve Sieve
Size, in Size, mm
l" 25.4
3/4" 19.1
1/2" 12.7
3/8" 9.53
#4 4.75
#8 2.36
#16 1.18
#30 0.60
#50 0.30
#100 0.15
#200 0.074
-- - . . ,-...
'
I\
\
' \
\
\
\
\
I\
~
' " ' I\.
)~
', ........ ~

10.000 1.000 0.100
Sieve Size, mm
Beaumont • Indio • Buena Park
Percent
Passing
100.0
100.0
100.0
100.0

96.1 74.4

49.7 31.0

17.9 9.8

5.7 0.010 0.001

~ Sladden Engineering
450 Egan Avenue, Beaumont, CA 92223 (951) 845-7743 Fax (951) 845-8863 Gradation
ASTM Cl 17 & Cl36
Project Number: 544-23355 December 18, 2023
Project Name:

Lab ID Number:

Sample ID:
100
90 80
70 60
bl)
.s
Vl
Vl 50 c<:S
P-s
~ 40
30 20
10 0
100.000
Twentynine Palms Highway
LN6-23487
BH-9 R-2@ 10' Soil Classification: SW-SM
Sieve
Size, in
l"
3/4"
1/2"
3/8"
#4
#8
#16
#30
#50
#100
#200
~ ~
T T

10.000
Sieve
Size, mm

25.4 19.1

12.7 9.53

4.75 2.36

1.18 0.60

0.30 0.15

0.074
~
[\
'
\
' \
\
\
'
I\
~
\
\
'\ ~
"- ,..____
'

1.000 0.100
Sieve Size, mm
Beaumont • Indio • Buena Park
Percent
Passing
100.0
100.0
100.0
100.0

97.8 78.2

53.7 35.2

21.3 12.9

8.4 0.010 0.001
+

~ Sladden Engineering
450 Egan Avenue, Beaumont, CA 92223 (951) 845-7743 Fax (951) 845-8863 Gradation
ASTM Cl 17 & C136
Project Number: 544-23355 December 18, 2023
Project Name:

Lab ID Number:

Sample ID:
on
i:::
";;j
Vl
{,:I
P.
~
100
90 80
70 60
50 40
30 20
10 0
100.000
Twentynine Palms Highway
LN6-23487
BH-10 S-2@ 10' Soil Classification: SW
Sieve
Size, in
l"
3/4"
1/2"
3/8"
#4
#8
#16
#30
#50
#100
#200
~ ~
- - 't-,,

10.000
Sieve
Size, mm

25.4 19.1

12.7 9.53

4.75 2.36

1.18 0.60

0.30 0.15

0.074
r\
i\
'
\
~
\
\
\
..
'
\
\
\
"I-..._
"r--....

I'll

1.000 0.100
Sieve Size, mm
Beaumont • Indio • Buena Park
Percent
Passing
100.0
100.0
100.0

99.4 94.5

72.2 46.2

25.3 12.4

6.5 3.7

0.010 0.001

~ Sladden Engineering
6782 Stanton Ave., Suite C, Buena Park, CA 90621 (714) 523-0952 Fax (714) 523-1369 45090 Golf Center Pkwy, Suite F, Indio, CA 92201 (760) 863-0713 Fax (760) 863-0847 450 Egan Avenue, Beaumont, CA 92223 (951) 845-7743 Fax (951) 845-8863 Date: December 18, 2023
Account No.: 544-23355
Customer: 29 Palms Hotel, LLC
Location: APN 0614-121-15, Twentynine Palms Highway, Twentynine Palms Area Analytical Report
Corrosion Series
pH Soluble Sulfates Soluble Chloride Min. Resistivity
perCA643 per CA 417 perCA422 perCA643
ppm ppm ohm-cm
BH-1@ 0-5' 8.0 40 30 4,600
BH-6@0-5' 7.3 40 30 7,000
C Rpt 544-23355121823

APPENDIXC

HISTORICAL EARTHQUAKES
Sladden Engineering
www.SladdenEngineering.com

HISTORICAL EARTHQUAKES 1932 TO PRESENT
MAGNITUDE > 3.0 (20 KILOMETER SEARCH RADIUS)
UNITED STATES GEOLOGICAL SURVEY (2023)

DATE/TIME LATITUDE LONGITUDE MAGNITUDE PLACE ID
2019-07-22T16:26:56.070Z 33.99667 -116.045 4.2 16km S of Twentynine Palms, CA ci38624623 20t4=1tn-i-ntr.1G-:M;-34Dr··- 34:0331:--7 --tt&.31:&8333- ---------3-3- llkm-S-0f-.losl'Hla--Tree, CA -W-7-2-18432-- 2012-07-08T10:50:03.130Z 33.96133 -116.1321667 3.27 20km SSW ofTwentynine Palms, CA cilll33514 2002-09-15T21:15:50.920Z 34.05433 -116.3201667 3.31 9km S of Joshua Tree, CA ci13813192 1999-10-17T10:37:39.420Z 34.31 -116.124 3.27 20km NNW of Twentynine Palms, CA ci3323954 1999-10-17T00:36:17.540Z 34.294 -116.058 3.41 17km N ofTwentynine Palms, CA ci9109752 1996-07-28T09:46:13.590Z 33.98933 -116.2761667 3.36 16km SSE of Joshua Tree, CA ci3271840 1995-04-09T23:0l:08.490Z 34.04 -116.322 3.29 11km S of Joshua Tree, California ci3209441 1994-08-07T23:43:32.880Z 33.992 -116.274 3.6 16km SSE of Joshua Tree, California ci3179575 1994-08-07T15:10:25.960Z 33.992 -116.274 3.95 16km SSE of Joshua Tree, California ci3179522 1993-08-21 T01:46:38.400Z 34.029 -116.321 5 12km S of Joshua Tree, California ci3118441 1993-06-26T12:48:02.460Z 34.076 -116.348 3.62 7km SSW of Joshua Tree, California ci3111385 1993-06-19T07:20:26.400Z 34.078 -116.349 3.24 7km SSW of Joshua Tree, California ci3110524 1992-06-28T13:50:16.340Z 34.084 -116.3566667 4.22 7km SW of Joshua Tree, CA ci2056998 1992-06-28T12:02:58.610Z 34.15117 -116.3546667 4.5 4km WNW of Joshua Tree, California ci12178459 1992-06-28T12:0l:16.190Z 34.12 -116.323 5.7 2km SSW of Joshua Tree, California ci3043630 1992-06-26T14:16:31.060Z 34.039 -116.316 3.34 11km S of Joshua Tree, California ci2056787 1992-06-18T08:06: 13.040Z 34.052 -116.329 3.01 9km S of Joshua Tree, California ci2056062 1992-06-11 T02:41:00.940Z 34.178 -116.352 3.32 6km NW of Joshua Tree, California ci2055360 1992-06-11T00:24:19.180Z 34.174 -116.35 4.34 6km NW of Joshua Tree, California ci2055346 1992-06-04T05:22:22.280Z 33.983 -116.262 3.01 18km SSE of Joshua Tree, California ci2054570 1992-05-18T20:39:41.440Z 34.041 -116.292 3.02 11km S of Joshua Tree, California ci2052769 1992-05-12T02:59:21.840Z 33.979 -116.258 3.36 18km SSE of Joshua Tree, California ci2051868 1992-05-12T02:32:52.540Z 33.985 -116.258 3.9 17km SSE of Joshua Tree, California ci3024923 1992-05-12T02:31:11.010Z 33.981 -116.26 4.38 18km SSE of Joshua Tree, California ci2051863 1992-05-08T15:10:59.060Z 34.043 -116.329 3.03 10km S of Joshua Tree, California ci2051341 1992-05-07T02:34:54.120Z 34.028 -116.309 3.42 12km S of Joshua Tree, California ci2051110 1992-05-06T01:40:21.380Z 34.032 -116.314 3.25 11km S of Joshua Tree, California ci2050929 1992-05-04T07:24:14.090Z 34.062 -116.319 3.18 8km S of Joshua Tree, California ci2050583 1992-05-02T13:41:59.370Z 33.995 -116.28 3.23 16km S of Joshua Tree, California ci2050248 1992-05-02T13:29:54.SOOZ 33.995 -116.283 3.1 16km S of Joshua Tree, California ci2050247 1992-05-02T12:46:53.290Z 33.99433 -116.277 4.1 16km SSE of Joshua Tree, California ci12178263 1992-05-02T07:04:32.810Z 33.998 -116.093 3.01 16km S of Twentynine Palms, California ci2050194 1992-05-01T06:03:27.420Z 34.035 -116.321 3.41 11km S of Joshua Tree, California ci2049987 1992-04-30T22:43:04.420Z 34.034 -116.318 3.02 11km S of Joshua Tree, California ci2049922 1992-04-30T01:50:43.460Z 34.021 -116.093 3.96 13km S of Twentynine Palms, California ci2049720 1992-04-29T18:32:40.560Z 33.985 -116.263 3.07 17km SSE of Joshua Tree, California ci2049642 1992-04-28Tll:32:14.360Z 34.034 -116.298 3.17 11km S of Joshua Tree, California ci2049292 1992-04-27T08:13:35.570Z 34.073 -116.326 3.29 7km S of Joshua Tree, California ci3019752 1992-04-26T18:04:18.900Z 34.051 -116.339 3.41 10km SSW of Joshua Tree, California ci2048839 1992-04-26T17:21:38.010Z 34.049 -116.335 4.42 10km SSW of Joshua Tree, California ci2048832 1992-04-25Tll:56:05.170Z 34.03533 -116.3068333 3.01 11km S of Joshua Tree, CA ci3101040 1992-04-25T08:31:02.930Z 34.04033 -116.3146667 3 10km S of Joshua Tree, California cil2177711 1992-04-25T04:40:52.650Z 34.05017 -116.2996667 3.15 10km S of Joshua Tree, CA ci2048385 1992-04-24T16:0l:05.560Z 34.122 -116.27 3.16 4km ESE of Joshua Tree, California ci2048228 1992-04-24T06:19:12.010Z 34.027 -116.316 3.07 12km S of Joshua Tree, California ci3097588 1992-04-24T01:15:51.220Z 34.047 -116.335 3.11 10km SSW of Joshua Tree, California ci2048033 1992-04-24T01:03:29.930Z 34.02 -116.295 3.2 12 km S of Joshua Tree, California usp00056a2 1992-04-23T19:33:40.000Z 34.137 -116.338 3.4 2 km W of Joshua Tree, California usp000569b 1992-04-23T18:06:40.720Z 33.98467 -116.2505 3.72 18km SSE of Joshua Tree, CA ci3017773 1992-04-23T14:53:44.230Z 33.985 -116.225 3.48 18km SSE of Joshua Tree, California ci3122328 1992-04-23T14:53:09.840Z 33.978 -116.235 3.45 19km SSE of Joshua Tree, California ci3122327 1qq?-04-?~T14 •4q•?.2.080Z 33.983 -116.229 3.3 19km SSE of Joshua Tree, California ci3131024 ~ Project No. 544-23355 Sladden Engineering
1 Report No. 23-12-620 Page 1058 of 1452
HISTORICAL EARTHQUAKES 1932 TO PRESENT
MAGNITUDE > 3.0 (20 KILOMETER SEARCH RADIUS)
UNITED STATES GEOLOGICAL SURVEY (2023)

DATE/TIME LATITUDE LONGITUDE MAGNITUDE PLACE ID
1992-04-23Tll:12:06.790Z 33.983 -116.229 3.56 19km SSE of Joshua Tree, California ci3120428 19-92-04-2-3T10:56:28.930Z 33.986 -116.225 3.15 1_8km_SSE ofJoshua Tree,_California ci3120196 1992-04-23T10:18:08.020Z 33.987 -116.228 3.23 18km SSE of Joshua Tree, California ci2047793 1992-04-23T09:58:09.540Z 34.033 -116.323 3.78 11km S of Joshua Tree, California ci3120177 1992-04-23T08:47:20.370Z 34.042 -116.332 3.64 10km S of Joshua Tree, California ci3119895 1992-04-23T08:47:04.220Z 34.033 -116.31 3.37 11km S of Joshua Tree, California ci3119894 1992-04-23T07:40:24.090Z 34.034 -116.234 3.07 13km SSE of Joshua Tree, California ci2047744 1992-04-23T06:36:28.840Z 34.05083 -116.3358333 3.56 10km SSW of Joshua Tree, CA ci3017753 1992-04-23T06:12:31.030Z 34.034 -116.311 3 11km S of Joshua Tree, CA ci3017430 1992-04-23T06:11:55.340Z 34.028 -116.321 3.58 12km S of Joshua Tree, California ci2047731 1992-04-23T05:58:07.900Z 33.977 -116.233 3.5 19km SSE of Joshua Tree, California ci2047728 1992-04-23T05:22:18.550Z 34.062 -116.325 3.83 8km S of Joshua Tree, California ci2047722 1990-04-22T01:10:36.410Z 34.034 -116.024 3.13 12km SSE of Twentynine Palms, CA ci1057566 1989-01-05T21:32:13.850Z 34.264 -116.004 3.11 15km NNE of Twentynine Palms, CA ci1017186 1988-02-29Tl5:25:06.900Z 34.032 -116.246 3.25 13km SSE of Joshua Tree, CA ci135912 1986-02-17T02:12:33.480Z 34.116 -116.03 3.94 5km ESE of Twentynine Palms, CA ci116008 1985-06-03T02:05:30.480Z 34 -116.098 3.21 16km S of Twentynine Palms, CA ci67587 1984-07-27Tl9:42:07.760Z 34.262 -116.15 3.5 16km NNW of Twentynine Palms, CA ci46108 1981-10-13T20:14:03.000Z 34.03167 -116.1346667 3.48 13km SSW ofTwentynine Palms, CA ci525470 1978-10-20T08:38:29.020Z 34.22117 -116.1823333 3.16 14km NW of Twentynine Palms, CA ci3343077 1973-05-08T12:41:25.810Z 34.23 -116.3108333 3.38 11km N of Joshua Tree, CA ci3319914 1973-05-03Tl0 :09 :46.850Z 34.23833 -116.1303333 3.54 12km NNW ofTwentynine Palms, CA ci3319904 1973-02-09T07:41:03.590Z 34.29783 -116.1226667 3.28 18km NNW ofTwentynine Palms, CA ci3320312 1972-12-19T22:32:21.830Z 33.95917 -116.1073333 3.53 20km S of Twentynine Palms, CA ci3320595 1972-01-28Tl 7:00:21.830Z 34.29333 -116.138 3.78 18km NNW of Twentynine Palms, CA ci3321554 1970-08-14T07:39:56.960Z 34.037 -115.9903333 3.37 14km SE ofTwentynine Palms, CA ci3323819 1970-04-02T09:29:54.200Z 34.13067 -116.1236667 3.37 5km W of Twentynine Palms, CA ci3324267 1969-06-11 T14:03:53.660Z 34.2215 -116.2851667 3.56 10km NNE of Joshua Tree, CA ci3327320 1969-02-05T06:01:46.580Z 33.98917 -116.2458333 3.24 17km SSE of Joshua Tree, CA ci3327816 1968-03-28T21:21:33.000Z 34.04617 -116.0803333 4.13 10km S of Twentynine Palms, CA ci3329115 1967-04-03T13:57:27.480Z 34.17033 -116.2071667 3.12 10km ENE of Joshua Tree, CA ci3329738 1964-07-22T23:40:29.090Z 34.15483 -116.1778333 3.37 10km W of Twentynine Palms, CA ci3330878 1963-12-20T10:27:58.460Z 34.17633 -116.1935 3.52 12km WNW of Twentynine Palms, CA ci3331069 1963-08-30Tll:21:04.270Z 34.14867 -116.2108333 3.03 10km E of Joshua Tree, CA ci3331207 1963-08-22T04:33:56.190Z 34.14483 -116.192 4.15 11km W of Twentynine Palms, CA ci3331259 1963-08-03T15:15:49.740Z 34.13333 -116.1605 3.15 8km W of Twentynine Palms, CA ci3331247 1963-07-30T22:45:57.410Z 34.15433 -116.1826667 3.45 10km W of Twentynine Palms, CA ci3331243 1963-07-30T17:47:42.750Z 34.14533 -116.1858333 3.15 10km W of Twentynine Palms, CA ci3331241 1963-07-30T17:28:26.030Z 34.13667 -116.1258333 3.07 5km W of Twentynine Palms, CA ci3331262 1963-07-30T10:25:24.890Z 34.16883 -116.1631667 3.17 9km WNW of Twentynine Palms, CA ci3331239 1963-07-30T06:34:56.850Z 34.16133 -116.189 4.64 11km WNW of Twentynine Palms, CA ci3331237 1963-07-24T11:41:52.960Z 34.17883 -116.1595 3.14 9km WNW of Twentynine Palms, CA ci3331305 1963-07-19T15:54:56.680Z 34.15567 -116.2053333 3.77 10km ENE of Joshua Tree, CA ci3331300 1963-07-19T08:33:54.030Z 34.16933 -116.1921667 3.25 12km WNW of Twentynine Palms, CA ci3331299 1963-07-18T19:37:44.980Z 34.165 -116.1376667 3.99 7km WNW of Twentynine Palms, CA ci3331297 1963-07-18T10 :40 :31.430Z 34.17617 -116.13 3.48 7km NW of Twentynine Palms, CA ci3331295 1963-07-17T23:11:07.100Z 34.149 -116.1876667 3.61 11km W of Twentynine Palms, CA ci3331291 1963-07-17T23:05:42. 750Z 34.15767 -116.067 3.49 2km NNE of Twentynine Palms, CA ci3331290 1963-07-17T20:44:34.660Z 34.12433 -116.15 3.07 7km WSW of Twentynine Palms, CA ci3331289 1963-07-05T08:27:11.980Z 34.188 -116.1868333 3.22 12km WNW of Twentynine Palms, CA ci3331275 1961-11-18T04:04:54.470Z 34.00233 -116.2176667 3.54 17km SSE of Joshua Tree, CA ci3344606 1959-10-04T05:06:14.870Z 34.1045 -116.1363333 3.02 7km WSW of Twentynine Palms, CA ci3297223 1 qc;q_nR-nl:ff07·1 R·09.830Z 34.20917 -116.1328333 3.04 10km NW of Twentynine Palms, CA ci3297165 ~ Project No. 544-23355 Slad<len Engineering
2 Report No. 23-12-620 Page 1059 of 1452

DATE/TIME
1958-03-01 T09:07:31.470Z
-195-7--1-2--1-2--l0&0Ml~98QZ
1956-09-26Tll:36:26.560Z
1956-09-20T06:23:51.180Z
1956-09-17T00:58:00.430Z
1956-09-17T00:03:36.310Z
1955-05-30T19 :15 :32. 780Z
1954-08-29T22:SO:OS.680Z
1949-05-06T02:48:37.6SOZ
1948-12-27Tll:19:06.830Z
1948-12-06T02:Sl:23.820Z
1948-02-28Tl 7 :24:44.620Z
1947-08-12T21:05:17.740Z
1947-07-24T18:30:20.140Z
1947-05-11 T05:06:20.940Z
194 7-05-06T08 :45 :Sl.200Z
1946-07-03T00:16:45.230Z
1946-os-12T04:42: 12.20oz
1946-05-12T02:46:S0.010Z
1945-03-29T04:04:20.680Z
1945-03-20T21:SS:08.220Z
1944-07-26T09:11:53.020Z
1942-12-04T21:25:09.510Z
1942-01-21 TOS:25:01.130Z
1941-12-23Tll:16:10.2302
1940-06-23T07 :07 :08.4102
1940-06-19T03:09:Sl.3102
1940-06-18T06:14:32. 7102
1940-06-14T21:58:Sl.1902
1940-06-01T06:54:28.0902
1940-06-01 TOS:56:46.3602
1940-06-0lTOS:27:01.9202
1940-05-22T14:10:08.5802
1940-0S-22T06:03:56.7602
1940-0S-19Tl9:39:43.0802
1940-05-19T02:26:03.1202
1940-05-18T07:21:34.4 702
1940-05-18T06:04:31. 7902
1940-0S-18TOS:S 1:21.9402
1940-05-18TOS:03:59.6602
1939-09-10Tl7:45:58.1902
1938-02-1ST07:56:15.1102
1938-02-1ST07 :45:38.1302
1938-02-08T07:39:25.1202
1934-06-26T01:22:43.3902
Stadden Engineering
~
HISTORICAL EARTHQUAKES 1932 TO PRESENT
MAGNITUDE> 3.0 (20 KILOMETER SEARCH RADIUS)
UNITED STATES GEOLOGICAL SURVEY (2023)

LATITUDE LONGITUDE MAGNITUDE PLACE

34.30133 -116.1868333 3.19 21km NNW of Twentynine Palms, CA ~.243S3----=1-l6-1935--- ... __ 4..34-_ _ _lfikm~.W.o.f_Twentynine Palms. CA

33.98717 -116.0793333 3.03 17km S ofTwentynine Palms, CA

33.964 -116.1776667 3.17 22km SSW of Twentynine Palms, CA

33.97883 -116.209 3.58 20km SSE of Joshua Tree, CA

33.96583 -116.2106667 3.6 21km SSE of Joshua Tree, CA

34.21817 -116.2063333 3.56 14km NE of Joshua Tree, CA

34.1315 -116.1015 3.16 3km WSW of Twentynine Palms, CA

34.0105 -115.9983333 3.01 16km SSE of Twentynine Palms, CA

34.0595 -116.1935 3.85 14km SE of Joshua Tree, CA

34.10467 -116.3553333 3.14 5km SW of Joshua Tree, CA

34.0705 -116.2091667 3.44 12km SE of Joshua Tree, CA

34.026 -116.3173333 3.22 12km S of Joshua Tree, CA

33.98583 -116.2681667 3.41 17km SSE of Joshua Tree, CA

34.30633 -116.1921667 4.66 22km NNW of Twentynine Palms, CA

34.28383 -116.2665 3.11 17km NNE of Joshua Tree, CA

34.217 -116.303 3.36 9km N of Joshua Tree, CA

33.99967 -116.1203333 3.08 16km SSW of Twentynine Palms, CA

34.01083 -116.1608333 3.17 16km SSW of Twentynine Palms, CA

34.151 -116.233 4.14 8km ENE of Joshua Tree, CA

34.23817 -116.1415 4.87 13km NNW of Twentynine Palms, CA

33.99517 -116.2725 3.6 16km SSE of Joshua Tree, CA

34.245 -116.285 3.1 12km NNE of Joshua Tree, CA

34.10083 -116.2601667 3.53 6km SE of Joshua Tree, CA

34.00183 -116.0833333 3.12 15km S of Twentynine Palms, CA

34.08817 -116.1713333 3.7 11km WSW of Twentynine Palms, CA

33.999 -116.244 3.21 16km SSE of Joshua Tree, CA

34.09633 -116.2073333 3.89 11km ESE of Joshua Tree, CA

34.08983 -116.3405 3.78 6km SSW of Joshua Tree, CA

34.15233 -116.216 4.37 9km ENE of Joshua Tree, CA

34.1395 -116.2311667 3.95 8km E of Joshua Tree, CA

34.1055 -116.2716667 4.56 5km SE of Joshua Tree, CA

34.10367 -116.3601667 3.92 6km SW of Joshua Tree, CA

34.03517 -116.3281667 3.26 11km S of Joshua Tree, CA

34.0875 -116.307 4.25 5km S of Joshua Tree, CA

34.05183 -116.2788333 4.32 10km SSE of Joshua Tree, CA

34.02583 -116.3145 4.96 12km S of Joshua Tree, CA

34.042 -116.2618333 4.52 11km SSE of Joshua Tree, CA

34.037 -116.3065 5.2 11km S of Joshua Tree, CA

34.089 -116.2818333 5.31 6km SSE of Joshua Tree, CA

34.04383 -116.2945 3.3 10km S of Joshua Tree, CA

34.13867 -116.1981667 3.42 11km E of Joshua Tree, CA

34.21633 -116.1655 4.27 12km NW of Twentynine Palms, CA

34.15967 -116.1143333 4.05 4km WNW of Twentynine Palms, CA

34.038 -116.068 3.09 11km S of Twentynine Palms, CA
3 ID
ci3296518
ci3296325
ci3295491
ci3295470
ci3295465
ci3295464
ci3297820
ci3298431
ci3355979
ci3356437
ci3356911
ci3357809
ci3358105
ci3358688
ci3358488
ci3358467
ci3359664
ci3360099
ci3360098
ci3360905
ci3360727
ci3366601
ci3366170
ci3365874
ci3365837
ci3365378
ci3365373
ci3365372
ci3365367
ci3365323
ci3365322
ci3365321
ci3365310
ci3365307
ci3365298
ci3365276
ci3365272
ci3365271
ci3365270
ci3365269
ci3365097
ci3364544
ci3364543
ci3364538
ci3362263
Project No. 544-23355
Report No. 23-12-620 Page 1060 of 1452

APPENDIXD

SEISMIC DESIGN MAP AND REPORT

SITE-SPECIFIC GROUND MOTION PARAMETERS
Sladden Engineering
www.SladdenEngineering.com

U.S. Seismic Design Maps https://www.seismicmaps.org/
1 of 3
USGS web services were down for some period of time and as a result this tool wasn't operational, resulting in timeout error.

USGS web services are now operational so this tool should work as expected.

OSHPD
APN 0614-121-15
Latitude, Longitude: 34.1343, -116.1482
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Date
Design Code Reference Document
Risk Category
Site Class
Type Value
Ss 1.861
s, 0.697
SMs 1.861
SM1 null -See Section 11 .4.8
Sos 1.241
So1 null -See Section 11.4.8
Type Value
SDC null -See Section 11 .4.8
Fa
Fv null -See Section 11 .4.8
PGA 0.821
FPGA 1.1
PGAM 0.903
TL 8
SsRT 1.861
SsUH 2.085
SsD 2.275
S1RT 0.697
S1UH 0.785
Description
12/18/2023, 8:44:19 N-/I.

ASCE7-16
D- Stiff Soil
MCER ground motion. (for 0.2 second period)
Description
MCER ground motion. (for 1 .Os period)
Site-modified spectral acceleration value
Site-modified spectral acceleration value
Numeric seismic design value at 0.2 second SA
Numeric seismic design value at 1.0 second SA
Seismic design category
Site amplification factor at 0.2 second
Site amplification factor at 1.0 second
MCEG peak ground acceleration
Site amplification factor at PGA
Site modified peak ground acceleration
Long-period transition period in seconds
Probabilistic risk-targeted ground motion. (0.2 second) Factored uniform-hazard (2% probability of exceedance in 50 years) spectral acceleration Factored deterministic acceleration value. (0.2 second) Probabilistic risk-targeted ground motion. (1.0 second) Factored uniform-hazard (2% probability of exceedance in 50 years) spectral acceleration. ~
en
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Map data ©2023
12/18/2023, 8:44 AM

U.S. Seismic Design Maps
Type Value
S1D 0.837
PGAd 0.945
PGAuH 0.821
CRs 0.892
----CR+- . -0.688-
Cv 1.472
2of3
Description
Factored deterministic acceleration value. (1 .0 second) Factored deterministic acceleration value. (Peak Ground Acceleration) Uniform-hazard (2% probability of exceedance in 50 years) Peak Ground Acceleration Mapped value of the risk coefficient at short periods
Mapped.llalue_oltbe.risk.coeflicJenLat_aperiod of 1 s
Vertical coefficient
https://www.seismicmaps.org/
12/18/2023, 8:44 AM

U.S. Seismic Design Maps https://www.seismicmaps.org/
3 of3

DISCLAIMER
While the information presented on this website is believed to be correct, SEAOC /OSHPD_ and its sponsors and contributors assume no responsibility or liability for its accuracy. The material presented in this web application should not be used or relied upon for any specific application without competent examination and verification of its accuracy, suitability and applicability by engineers or other licensed professionals. SEAOC / OSHPD do not intend that the use of this information replace the sound judgment of such competent professionals, having experience and knowledge 1n the fie@ of practice, nor to substitute tor the standard of care required of such professionals in interpreting and applying the results of the seismic data provided by this website. Users of the information from this website assume all liability arising from such use. Use of the output of this website does not imply approval by the governing building code bodies responsible for building code approval and interpretation for the building site described by latitude/longitude location in the search results of this website. 12/18/2023, 8:44 AM

Stadden
~ Engineering
PROBABILISTIC SPECTRA1
2% in 50 year Exceedence
Max Directional Probabilistic Project No: 544-23355
Period UGHM RTGM
Scale Factor' MCE

0.010 0.837 0.787 1.19 0.937

0.100 1.369 1.320 1.19 1.571

0.200 1.814 1.759 1.20 2.111

0.300 2.089 1.958 1.22 2.389

0.500 2.089 1.901 1.23 2.338

0.750 1.747 1.575 1.24 1.953

1.000 1.496 1.329

2.000 0.825 0.732

3.000 0.541 0.479

1.24 1.24

1.25 1.648

0.908

0.599
1 Data Sources:
https://earthguake.usgs.gov/hazards/interactive/
https :ljearthguake. usgs.gov / design ma ps/rtgm/

4.000 0.374 0.331 1.25 0.414

5.000 0.277 0.243 1.26 0.306 2 Shahi-Baker RotD100/RotD50 Factors {2014) Probabilistic PGA: 0.837
Is Probabilistic Sa(max)<l.2F,? NO
·1 1 t·· jl. I __ 11 J.llllJ)II IJT1l11II I ..• 11
r f:.·-4 + l- i 11>R?rAr1L,5r11i. ~~~RI H H -- - t. 1--uGHM 1 1 • 1 • . ~i, sctr~ .. ~ESf ~N~E jA qc1
ELERA110N s . Lf 1 __ RTHM
,so I il'b · ,1·. 1 • _, - '· t-1 1 1 • • - Ii' • !\. ~ 1 i . ] ~. -. . -· • -• j . 1 I

2.00 ,;, 1 • .-~ l~l . I_ • ~ ' •. •• ··j ,_ :II • 1· I - I • • • i _ I . . . ... "- ' I ,_ • + - - - ,_ - " - . -· I •.•. !·. . I~ 'r 1 ~ I r'I• j 1 - - • •• - •• ~ 1 1 , 1 s rl · • I( ""'-"-~ I 1 i i t I
'i 1.50 I . l'. .... ~. . .I I I.. . . I • I Tl' .ii - • I i'i._,.... ~~ • I - l . • .. e • 1 1 .
1 . · ~~~ " 1 + 1 . . . 1 - <t I I r-...j...., I ... I... .1 -·· r • r r , - :-..!,,.._ ""'-r-...:. 1 1 , 1 I I I ,

1.00 I j J -. j ·1·. IJ .. ,. l""r,..~i"' I .. -1· .. . . - I I • 1 . r. - 1 . ~ i 11 ·1· + - -1 I 1: •• -· 17';:,~. -.. -- t t j : - j l 11 ] 1 l - ' . I 1 I 1 · J l ~~ · + - 1 1 1 u.· 1--1
a.so I I I t . ·- . 171• I J l J . . . • I • .. . , I 1 l i -1- l1 1- - j I u 1 I i Ii 1 d )j : j j ! 7 0.00

3.oo 7 I
--Probabilistic MCER

0.000 1.000 2.000 3.000 Period (seconds) 4.000 5.000
I
! _J

Sladden Engineering
~
Period

0.010

0.020

0.030

0.050

0.075

0.100

0.150

0.200

0.250

0.300

0.400

0.500

0.750

1.000

1.500

2.000

3.000

4.000

5.000

3.50 DETERMINISTIC SPECTRUM
Largest Ampl~udes of Ground Motions Considering All Sources Calculated using Weighted Mean of Attenuation Equations' Controlling Source: Pinto Mountain
Is Probabilistic SaIm,, I<1.2Fa? NO
Deterministic PSa Max Directional Scale
Median + l.o for 5%
Factor2 Deterministic MCE
Damping

0.997 1.19 1.187

1.006 1.19 1.197

1.017 1.19 1.211

1.059 1.19 1.260

1.243 1.19 1.480

1.456 1.19 1.732

1.752 1.20 2.103

1.964 1.20 2.357

2.161 1.21 2.615

2.278 1.22 2.779

2.369 1.23 2.914

2.335 1.23 2.872

1.974 1.24 2.448

1.696 1.24 2.103

1.223 1.24 1.517

0.925 1.24 1.147

0.627 1.25 0.784

0.421 1.25 0.527

0.304 1.26 0.383
Section 21.2.2
Scaling Factor
Applied

1.187

1.197

1.211

1.260

1.480

1.732

2.103

2.357

2.615

2.779

2.914

2.872

2.448

2.103

1.517

1.147

0.784

0.527

0.383
Project No: 544-23355
Is Determinstic Sa1max1<1.5*Fa? NO
Section 21.2.2 Scaling Factor: N/A
Deterministic PGA: 0.997
Is Deterministic PGA >=FPG.*0,5? YES
1 NGAWest 2 GMPE worksheet and
Uniform California Earthquake Rupture
Forecast, Version 3 (UCERF3) - Time
Dependent Model
2 Shahi-Baker Rot0100/Rot050 Factors
(2014)
: , 1 I + J + I ) 11 I j iq~e~M,~1srr1c McE~ 1 1 j ~-J : 1 rr 1 1 ,oo tf-H I l ! I 1 WllRA~!RESPCllN~I Af~LERA-hP~s! ii fl lint· ... 1 1·· .. ·•·j· .... 1 I l · .. .. .. ... . . I_ • •• , I •••• i 1 - 1 , ! 11 __ , t. ··_ I· • 1 __ •. l ···j J_j·· ,i l
_...,.. Deterministic
MCER
2_50 1 1 1 1 1 i 1 1 r . I l • •
11 .. -_ j I· ~ \ . j J •. + ·j 1__ -I• . .. 1 - I • ••• I •• i ' T ' I _ /IJJ_-I - 1\··+J 1 .•.•.... jl _j··
.!! 2.00 H_ 1 , ___ r_ +_ .. 1_ , r- + · 1 •••• 1 1 , 1 c: !j I'\ 11 • 1 l j . I Lj_._ t ___ '· I I ·\. LL l j ' t •• l ·j.--. . • • ·.··t . • J_ • I B I l__i_l ' j I I 1', I . - . l • i • 11 ~ 1.50 Ii , _W , r · , ',; • l 1 • ·_. 1, • •• • • • I . +I .... J I " I I I .·_·1• · __ itr_J_·._1_• ._
1__ j Kr--. •• j I I 1 '
1 I .' l . I . "i-- I l • 1.00 i I • 1 . t i 1 -_1_ •. I I ~ '"' 1 I j I 1 I ' ! -1 J ! ... j.. .. I 11_ I . . ·1 I I I I I t_ !. I t f j : - : ' ··-· • --- -~ r I J_ 1 jj· r_ ._. ,_ 1 ...
' .. l ·_,_ . . . . ! ...:_ i ·•· • • 1

0.50 j .I.. . I ·_1 I ' !_! _ I j .. _--f i I _I ... ~; t t I - 1 1· j j 1 .I ~- I I t I . j l1 ! . ... I -1 •• : 17""t-+-4-• l i 1 : .. •I' - i . -•-r _! . . • , : t I J •-. i .. I l_ , . ·_ J_ i r j· I l t l • .-i-.-_'_ :
'· 1 1 . J i .. - - · - - I . .! . 1 1 • + • 1 - -

0.00 I ! 1 , ' j I I I I . -I -I I ' T i !1·
. . . I ' I I I I ,_11 I 1 • 1 1 I 111 I .
1 l ! • •• ~II··. I j I
' '
I I

0.000 1.000 2.000 3.000 4.000 5.000
Period (seconds)

~
Period Probabilistic
MCE

0.010 0.937

0.100 1.571

0.200 2.111

0.300 2.389

0.500 2.338

0.750 1.953

1.000 1.648

2.000 0.908

3.000 0.599

4.000 0.414

5.000 0.306
SDS:

SDl:

SMS:

SMl:

Site Specific PGAm:

SITE SPECIFIC SPECTRA
Deterministic Site-Specific

MCE MCE

1.187 0.937

1.732 1.571

2.357 2.111

2.779 2.389

2.872 2.338

2.448 1.953

2.103 1.648

1.147 0.908

0.784 0.599

0.527 0.414

0.383 0.306
ASCE 7-16: Section 21.4
Site Specific
Calculated I Design
Value

1.433

1.210

2.150

1.815

0.837
Value

1.433

1.210

2.150

1.815

0.837
Site Class: D measured
Seismic Design Category - Short* D
Seismic Design Category - ls* D
* Risk Categories I, II, or Ill
Stadden Engineering
Design Response
Spectrum (Sa)
ASCE 7 SECTION 21.3 80% Genlral
Period General Spectrum Response Spectrum

0.624 0.005 0.516 0.413

1.047 0.010 0.536 0.429

1.407 0.020 0.576 0.461

1.593 0.030 0.616 0.492

1.559 0.050 0.695 0.556

1.302 0.060 0.735 0.588

1.099 0.075 0.794 0.636

0.605

0.399

0.090 0.854 0.683

0.100 0.894 0.715 J

0.276 0.110 0.934 0.747

0.204 0.120 0.973 0.77~

0.136 1.037 0.83

0.150 1.093 0.87

0.160 1.132 0.906

0.170 1.172 0.938

0.180 1.212 0.96~

0.200 1.241 0.99

0.250 1.241 0.99

0.300 1.241 0.993

0.400 1.241 0.993

0.500 1.241

0.99~ 0.600 1.241 0.99

0.640 1.241 0.99

0.750 1.241 0.99

0.850 1.241 0.993

0.900 1.241 0.99;

0.930 1.241 0.99

1.000 1.162 0.92

1.500 0.774 0.620

2.000 0.581 0.465

3.000 0.387 0.31j

4.000 0.290 0.23

5.000 0.232 0.186
Project No: 544-23355
J

3.50 rfn .... f 1· l $JE1-~ ~E~~,~J14dd~1Mi'_~ 1
•• ~ j.; '. --4- • - - - f . + - - - - t -t-- . - . - - I . r 1 . . I . . . . l . . . .. -~ I
' I

3.00 I I ' . . I
UJI j • +fjj , > , , , ,_, 4 , L J - -· ~ - I-~
1~ ,.
:: .. ili[N +...-• -+ -
+.· +
r-+--+-
-+ ➔--, +-·+ + ·+ -1- .j. --1

2.50 HH H+H l ~HHJHHI !~H • -I ! i 11 1--+--+ -+-!- -1--+ -+ !--·-+-I + -+ + - t + .j. I· + l -1---

2.00 I
§
C
0 ~
~
t
ii
'-'
~ 1.50
• 1fil - f t.f f If 111 j
t ITTTKm ~-. •. I . .j lj l _.j· I 11 ~1-J·· i --J•• ·j t j !-j. j· j·j·. ·.j j •t~ I ] j . t ·1 t t . I J j . - I I ~r;rr1 - --- L [

0.50 fr--r-rt1-H-ttt-tt-t-H----t-t-=T"'k~~++-~~~11:L_LJ_JJ ,-l j_-__,_ -~---: ----- ... : -t. J l • ff __ ffi. ~I 1 ~I ~~~~m1 0.00 I • - •• - - - - - -- I j- . ... -- . - . ! !° • t ~ I-: -r- - [ f I

0.000 1.000 2.000 3.000 4.000 5.000
Period (seconds)
- Probabilistic MCE
- Deterministic MCE
- •- Site-Specific MCE I
Design Response Spectrum
~ ASCE 7 Section 21.3 General Spectrum
..,._80% General Response Spectrum

City of Twentynine Palms
Ofland Hotel Initial Study
F
APPENDIX F: Preliminary Drainage Report
Available on the City of Twentynine Palms Website:
www.ci.twentynine-palms.ca.us

PRELIMINARY DRAINAGE STUDY
FOR
Proposed Ofland Twentynine Palms
APN 0614-121-15
City of Twentynine Palms, California
County of San Bernardino
Job No. 227523-0000210.00
February 22, 2024
Prepared by:
42-829 Cook Street, Suite 104
Palm Desert, California 92211
Phone 760.341.3101
Fax 760.341.5999
Prepared for:

Ofland Hotels
4605 Post Oak Place Drive, Ste. 280
Houston, Texas 77027
PREPARED UNDER THE SUPERVISION OF:

NV5, INC.
_________________________________________ _____________________ BRIAN WIESE, P.E. DATE
NV 5

Preliminary Offsite Drainage Study for Ofland Twentynine Palms APN 0614-121-15

Job No.227523-0000210.00

TABLE OF CONTENTS
I. INTRODUCTION
A. Purpose of Study ..........................................................................................................4 B. Scope ............................................................................................................................4 II. SITE AREA
A. Area Characteristics .....................................................................................................4 B. Soils Group...................................................................................................................4 C. Land Use ......................................................................................................................5 D. Flood Insurance Rate Maps (FIRM)............................................................................5 E. Rainfall Intensity ..........................................................................................................5 F. Antecedent Moisture Condition (AMC).......................................................................5 III. HYDROLOGIC METHODOLOGY
A. Unit Hydrograph Method.............................................................................................6 B. Rational Method...........................................................................................................6 C. Storm Frequency ..........................................................................................................6 IV. HYDROLOGIC RESULTS
A. Offsite Basin ................................................................................................................7 B. Pre and Post Onsite Development................................................................................7 V. SUMMARY
A. Recommendations........................................................................................................9 B. Conclusions..................................................................................................................9 C. References....................................................................................................................9 NIVIS

Preliminary Offsite Drainage Study for Ofland Twentynine Palms APN 0614-121-15

Job No.227523-0000210.00

APPENDICES
Appendix I
Figures

1. Vicinity Map

2. Flood Insurance Rate Map (FIRM)

3. Hydrologic Soils Map

4. Point Precipitation Frequency Estimates – NOAA Atlas 14, Volume 6, Version 2 TWENTYNINE PALMS
Station ID: 04-9099

5. Figure ADD-1 Antecedent Moisture Condition (AMC)
Appendix II
Calculations
• Infiltration Rate For Pervious Areas Versus SCS Curve Numbers • CivilD Rational Method – Existing Offsite Time of Concentration • CivilD Unit Hydrograph Method – Existing Offsite
• SCS Incremental Runoff Volume Estimation
• Hydraulic Calculation (Manning’s) – Diversion 1
• Hydraulic Calculation (Manning’s) – Diversion 2
Appendix III
Maps
• Offsite Hydrology Map
NIVIS

Preliminary Offsite Drainage Study for Ofland Twentynine Palms APN 0614-121-15

Job No.227523-0000210.00
I. INTRODUCTION
A. Purpose of Study
This study shall provide the offsite hydrologic analyzes in accordance with the San Bernardino County drainage requirements. The proposed project consists of a 152.7 acre parcel on which a destination resort consisting of 130 hard cabins, 2 swimming pools, 2 clubhouses, employee housing, outdoor theater screen, as well as other possible amenities, are proposed.

Hydrologic and hydraulic calculations were performed using methodologies defined in the San Bernardino County Flood Control District Hydrology Manual (August 1986) and County of San Bernardino Hydrology Manual Addendum for Arid Regions (April 2010), as required by the City of Twentynine Palms.

B. Scope
This study involves the hydrologic analyses of approximately 472 acres of upstream offsite watershed that will impact the existing project site.

Runoff values for the 100-year, 24 hour storm frequency have been determined for the offsite drainage tributary using the Rational Method. The runoff values will be used to determine how best to situate and protect the proposed structures from that storm and allow the drainage to continue through the site and exit the property in its natural historic pattern. Structures will need to be located on pads elevated above the ground surface and anticipated storm flows.

II. SITE AREA
A. Area Characteristics
This site is currently bounded by Twentynine Palms Highway on the north, Sullivan Road on the south, Shoshone Valley Road on the east and, and Lear Avenue on the west.

The property is undeveloped, desert terrain with scattered native plants sloping from the south towards the north with approximate slopes of 5%. The offsite drainage area to the south is similarly undeveloped, desert terrain with scattered native plans. This area slopes towards the project site from south to north with approximate slopes of 5%.

B. Soils Group
Per San Bernardino County Hydrology Manual, Addendum for Arid Regions (April 2010), soil grouping information was found from the NRCS Web Soil Survey (copy of analysis enclosed in Appendix I). It was determined that approximately 53% of the offsite watershed is within a Soil Type “A”. The small rocky hills at the southern end of the offsite watershed are within Soil Type “D” and make up 12% of the area. The NIVIS

Preliminary Offsite Drainage Study for Ofland Twentynine Palms APN 0614-121-15

Job No.227523-0000210.00
final 35%, covering the offsite area directly south of the project site, did not have data available in the Web Soil Survey so a Soil Type “B” was assumed based on Plate C-3 of the San Bernardino County Flood Hydrology Manual.

C. Land Use
The existing Land Use Zoning classification for this site is RS-E (Single Family Residential Estate, 2.5 acre minimum) but is proposed to change to CT (Tourist Commercial) with this project.

D. Flood Insurance Rate Maps (FIRM)
The site is located in Zone X of the Federal Emergency Management Agency (FEMA) Flood Insurance Rate Maps (FIRM), San Bernardino County, California and incorporated areas panel 8175 of 9400 with map number 06071C8175H dated September 2, 2016. A Zone X is defined as areas determined to be outside of the 0.2% annual chance of flood or a 1% annual chance of flood with average depths of less than 1’ or with drainage areas less than one square mile. The FIRM for this project is located in Appendix I.

E. Rainfall Intensity
The rainfall data used in the study are per NOAA Atlas 14, Volume 6, Version 2 as recommended by the San Bernardino County Hydrology Manual, Addendum for Arid Regions (April 2010). Data from the Twentynine Palms Station ID: 04-9099 is included in Appendix I.

F. Antecedent Moisture Condition (AMC)
Per San Bernardino County Hydrology Manual, Addendum for Arid Regions (April 2010), this project lies within the area mapped as AMC1 on Figure ADD-1 as included in Appendix I.

III. HYDROLOGIC METHODOLOGY
`
Description of Hydrologic Modeling Software
The CivilDesign Hydrology-Hydraulics software, Rational Hydrology program package was used to perform the hydrologic calculations.

The CivilDesign Program is a computer-aided design program where the user develops a node-link model of the watershed. The intensity-duration-frequency relationships are applied to each of the drainage areas in the model to get the peak flow rates at each point of interest.

The model follows the San Bernardino Hydrology Design methodology.

NIVIS

Preliminary Offsite Drainage Study for Ofland Twentynine Palms APN 0614-121-15

Job No.227523-0000210.00
A. Rational Method
The materials included with this study are presented to satisfy the requirements set forth in the San Bernardino County Flood Control District (SBCFCD) Hydrology Manual.

Existing offsite watershed was evaluated and runoff values were generated by the Rational Method. The Rational Method was also used to calculate the peak Q’s for the 100-year storm and the times of concentration for both the pre-development conditions and post development conditions for the project on-site.

C. Storm Frequency
Per San Bernardino County criteria, the 100-year, 1-, 6-, 24- hour storm frequency was used to calculate peak flows using the Rational Method Analysis. The hydrologic frequency obtained from the Point Precipitation Frequency Estimates NOAA Atlas 14 are 2.03”(1 hour storm), 2.72” (6 hour storm) and 3.66” (24 hour storm), respectively.

IV. HYDROLOGIC RESULTS
A. Offsite Basin
The 100-year, 24-hour peak discharge values at the most downstream point for the offsite basin has been determined to be 487 cfs (cubic feet per second). Runoff from the offsite basin of approximately 472 acres (see offsite hydrology map in Appendix III) impacts the project site along the southerly boundary of the property. These values are provided in a detailed analysis provided in Appendix II of this report.

The offsite runoff value for the project is provided in Table 1 below.

TABLE 1

EXISTING OFFSITE PEAK FLOW RATES
Unit Hydrograph
Basin (Offsite)
Area (acres) 100-year (cfs) 24 hour
Peak Flow
OFFSITE-EX 472 487
NIVIS N0LTE V~ICALP'IV■

Preliminary Offsite Drainage Study for Ofland Twentynine Palms APN 0614-121-15

Job No.227523-0000210.00
V. SUMMARY
A. Recommendations
The following recommendations have been provided to facilitate safety, both public and private, for the proposed development.

1. Proposed finished floor elevations for the development shall be determined by the Final Drainage Study. Finished floors elevations for the proposed buildingsshould be located at a minimum of 1’ above the highest ground elevation beneath the building footprint.

2. A Final Drainage Study shall address any modification or changes for the offsite and onsite drainage conditions. This Preliminary Drainage Study only addresses the existing offsite watershed basins.

3. Proposed retention basin design will be determined during final design based upon the final drainage study. Proposed retention basins should be sized to retain, at a minimum, the incremental increase in storm water runoff volume.

4. Runoff should follow existing drainage patterns when leaving the site.

B. Conclusions
Development of this project can be accomplished in a manner that will maintain historical downstream flow patterns. The development should not adversely impact surrounding or downstream properties and the effects of post-development incremental increase flows shall be mitigated and designed in the Final Drainage Study for the onsite development.

C. References

1. CivilDesign Engineering Software, Rational Method Hydrology System Model, © 1989-2001, Version 6.4.

2. County of San Bernardino, Hydrology Manual, ©August 1986.

3. SB County Hydrology Manual, Addendum for Arid Regions (April, 2010)

4. USGS Indian Cove Quadrangle, 1995
NIVIS

Preliminary Offsite Drainage Study for Ofland Twentynine Palms APN 0614-121-15
Job No.227523-0000210.00

APPENDIX I
Figures
• Vicinity Map
• Flood Insurance Rate Map (FIRM)
• Hydrologic Soils Map
• Point Precipitation frequency estimates – NOAA Atlas 14, Volume 6, Version 2 Twentynine
Palms Station ID: 04-9099
NIVIS

VICINITY MAP
SITE
DATE:2/22/2024 PA TH:Y: \227523-0000210.00\CADD\EXHIBIT\DRAINAGE XHIBITS PAGE SEllJP:VICINITY MAP.DWG DRAWING NAME:VICINITY MAP.DWG TW[N ryN/N PALM HWY (SR-62)
Cl t----t----t--;ar''!--~"",--,1
0:::
:z:

AL TA LOMA OR

NOT TO SCALE

NIVIS VICINITY MAP

BEYOND ENGINEERING
73-185 IIQIWAY 111, SUlE A
760.341.3101 1D. 760.341.5999 FAX
PM.II IJEliERT, CA 92260
WWW.NW.(:(11 PREPARED FOR: CITY OF TWENTYNINE PAMS DA TE SUBMITTED: FEB 2024

SHEET NUMBER
OF 1 SHEETS

JOB NUMBER
227523-0000210 Page 1079 of 1452
National Flood Hazard Layer FIRMette
0 250 500 1,000 1,500 2,000
Feet
Ü

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

SPECIAL FL OOD

HAZARD AREAS
Without Base Flood Ele vation (BFE)
Zone A, V, A99
With BFE or Depth Zone AE, AO, AH, VE, AR
Regulatory Floodway

0.2% Annual Chance Flood Haz
of 1% annual c hance flood with average
depth less than one f oot or with drainage
areas of less than one square m
Zone X
Future Conditions 1% Annual
Chance Flood Hazard Zone X
Area with R educed Flood Risk due t o
Levee. See Notes.Zone X
Area with Flood Risk due t o LeveeZone D
NO SCREEN Area of Minimal Flood Hazard Zone X
Area of Unde termined Flood Hazard Zone D
Channel, Culv ert, or Storm Sewer
Levee, Dike, or Floodw all
Cross Sections with 1% Annual C

17.5Water Surface Elevation
Coastal Transect
Coastal Transect Baseline
Profile Baseline
Hydrographic Feature
Base Flood Ele vation Line (BFE)
Effective LOMRs
Limit of Study
Jurisdiction Boundar y
Digital Data A vailable
No Digital Data A vailable
Unmapped
This map complies with FEMA's standards f or the use of digital flood maps if it is no t void as described belo w.

The basemap sho wn complies with FEMA's basemap
accuracy standards
The flood hazard inf ormation is deriv ed directly fr om the authoritativ e NFHL web services provided by FEMA. This map was exported on 1/19/2024 at 9:44 AM and does no t
reflect changes or amendments subsequent t o this date and time. The NFHL and ef fective information ma y change or become super seded by new data over time.

This map image is v oid if the one or more of the f ollowing map elements do no t appear: basemap imager y, flood zone labels, legend, scale bar , map creation dat e, community identif iers, FIRM panel number , and FIRM ef fective date. Map images f or unmapped and unmodernized areas canno t be used for
regulatory purposes.

Legend

OTHER AREAS OF

FLOOD HAZARD

OTHER AREAS

GENERAL

STRUCTURES
OTHER

FEATURES

MAP PANELS
8 B 20.2
The pin displa yed on the map is an appr oximate
point select ed by the user and does no t represent
an authoritativ e property location.
1:6,000
116°9'8"W 34°8'12"N
116°8'31"W 34°7'42"N
Basemap Imager y Source: USGS N ational Map 2023
c:::::::::J
1111111

Hydrologic Soil Group—Joshua Tree National Park, California; and Mojave Desert Area, West Central Part, ...

Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
2/9/2024

34° 7' 49'' N
116° 9' 37'' W
34° 7' 49'' N
116° 7' 53'' W
34° 5' 55'' N
116° 9' 37'' W
34° 5' 55'' N
N
116° 7' 53'' W
Map projection: Web Mercator Corner coordinates: WGS84
0 500 1000 2000 3000
Feet
0 250 500 1000 1500
Meters
Map Scale: 1:17,200 if printed on A portrait (8.5" x 11") sheet. ~
~
USDA
= Page 1081 of 1452

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
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Soil Rating Points
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Background
Aerial Photography
The soil surveys that comprise your AOI were mapped at
1:24,000.

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: Joshua Tree National Park, California Survey Area Data: Version 13, Aug 30, 2023
Soil Survey Area: Mojave Desert Area, West Central Part, California
Survey Area Data: Version 16, Aug 30, 2023
Your area of interest (AOI) includes more than one soil survey area. These survey areas may have been mapped at different scales, with a different land use in mind, at different times, or at different levels of detail. This may result in map unit symbols, soil properties, and interpretations that do not completely agree across soil survey area boundaries.

Soil map units are labeled (as space allows) for map scales 1:50,000 or larger.

Date(s) aerial images were photographed: Feb 27, 2021—May 27, 2021
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.

Hydrologic Soil Group—Joshua Tree National Park, California; and Mojave Desert Area, West Central Part, California Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
2/9/2024

USDA
=
□
D
D
D
D
D
D
D
D
.....,.
.....,.
□
■
■
□
□
,,..._,
t-+-t
~
~
,..,,.
~
•

Hydrologic Soil Group
Map unit symbol Map unit name Rating Acres in AOI Percent of AOI 3325 Ironped-Rock outcropHexie complex, 30 to
60 percent slopes
D 59.6 12.4%
3680 Morongo loamy sand, 2
to 8 percent slopes,
dry
A 253.9 52.8%
Subtotals for Soil Survey Area 313.5 65.2%
Totals for Area of Interest 481.1 100.0%
Map unit symbol Map unit name Rating Acres in AOI Percent of AOI NOTCOM No Digital Data
Available
167.5 34.8%
Subtotals for Soil Survey Area 167.5 34.8%
Totals for Area of Interest 481.1 100.0%
Hydrologic Soil Group—Joshua Tree National Park, California; and Mojave Desert Area, West Central Part, California
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
2/9/2024

B -Assumed from SBCo
Hydrology Manual Map
USDA
=

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
Tie-break Rule: Higher
Hydrologic Soil Group—Joshua Tree National Park, California; and Mojave Desert Area, West Central Part, California
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
2/9/2024
~ Page 4 of 4

Precip1tat10n Frequency Uata Server Page 1 ot 4
NOAA Atlas 14, Volume 6, Version 2

TWENTYNINE PALMS
Station ID: 04-9099
Location name: Twentynine Palms, California,
USA*
Latitude: 34.1281°, Longitude: -116.0369°
Elevation:

Elevation (station metadata): 1975 tt••
• source ESRI Maps
•• source USGS

POINT PRECIPITATION FREQUENCY ESTIMATES
Sanja Perica, Sarah Dietz, Sarah Heim, Lillian Hiner, Kazungu Maitana, Deborah Martin, Sandra Pavlovic, lshani Roy, Carl Trypaluk, Dale Unruh, Fenglin Yan, Michael Yakla, 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 Average recurrence interval (years)
1 2 I 5 I 10 25 50 100 I 200 I 500 I 1000
5-min 0.157 0.221 0.308 0.383 0.490 0.577 0.669 0.769 0.911 1.03 (0.130-0 192) (0.182-0..270) (0.254,0.37 7 0.313-0.473) (0.388-0.625' (0.44 7.{) 752) [O 506,0.693 (0 566-1,06) 0.644-1.30) (0.702-1 52) 10-min 0.226 0.316 0.441 0.549 0.702 0.827 0,959 1.10 1.31 1.47 0 187-0.275 0 261-0.386 0.364-0.541 0.448-0.678 O.S56-0,696 (0 641-1 08\ (0.726-1 28\ 0.811-1,511 uo,923-1.87 (1.01-218) B 0.273 0.382 0.534 0.663 0.849 1.00 1.16 1.33 1.58 1.78 tro.22s-o.333l 0.3'I6,0.~67] l!0.44o,o.ss4' 0,542-0.019 (0 672-1 OBJ {0. 77 5. 1 30) (0,878-1 55] 0981-183) (1.12-2 28) [1 22-2.64) 130-min I 0.393 0.650 0.788 0.955 1.22 1.44 1.87 1.92 2.27 2.56 (0,325-0.479) 0.455-0.673) (0.633-0.M 1 (0,760-1 18) (0.967-1.56) (112,1.88'] (1.26-2,23) (1.41-2.63) (1.61 3.25) (1 75 3,79) ! so-min 1 0.476 0.688 0.932 1.16 1.48 1.76 2.03 2.33 2.76 3.11 (0.384-0.582) 0.552-0.816) (0,768-11<1) (0.947-1.43) (1 17,189) (1.35-2 28) ( 1.53-2.70) (1 71-3, 19) (1 95-3,94) (2.12-4.60) B 0.551 o.1s2 1.03 1.2a I 1.63 II 1.93 I 2.24 2.58 3.07 3.48 110.456-0.672' 0.622-0.919J (0.853-1.27) (1,05-1,58) : (129-209! :: p.~9-2 51) : (1.69-2,99) (1,90-3.Sd) I (2 17-4.39) 12,30-5. 151 I
B 0,589 o.803 I 1.10 II 1.36 II 1.74 II 2.os II 2.38 I 2.75 0 488-0,719 0.66_3-0.981 : (0.906-t.35! :: p, 11-1.66) :: ! 1.38-2.22! :: ( l.59,2.67) :: ( I 80,3. 18) : I 12.02,3.Tll I 12.t/4~68} 11 12.:a~s\91 I E 0.668 0.918 1.27 1.57 2.00 I 2.35 II 2.12 I 3.13 3.71 4.19 1 '0.553-0.015) (0.759-112) ( 1,04-1 ,55) (1 28-1 93) 11 58-2 SSJ : p 82-3,06) :: (2 06-3,64/ : I 12,30-4.30) I (2..62-5 31 l (2,86-6 20) 12-hr 0.733 1.04 1.46 1.81 2.30 2.68 3.09 3.51 4.11 4.58

0.607-0.895) (0.861-1.27) (1.20-1,79) (1.48-2 23) (1.82-2 93) (2.00-3.50) (2.34-4.12) (2.59-4,82) ~
(2.90-587)~ (3.13-678)
24-hr 0.828 1.22 1.74 2.16 2.74 3.20 3.86 4.14
I0.733-0.953 (1.06-1 41) (1.53-2.01) (1.89-2.52) (2.33-3,30) (2.68-3.93) (2 97-4 60) (3.27-5.35) ) 2-day 0.963 1.44 I 2.09 II 2.62 I 3.37 3.96 4.57 5.22 2 (0,853-1 111 11.28-·l.661 : !1 04.2.411 . : I2.3 -J.oe1 : 12.86-4.06\ (3.29-4.87) (3.71,5, 75) I l<\.12-6.74.J ll E 1.01 1.52 2.21 2.80
I (3.~~\11 I

4.29 4.99 5.74 6.79 7.64
(0 891-116) (1,34-1.75) (1.95-2.56) (2 45-3,26) (3.57-5 27) (4.0S·G.28) (4.53-7 42) (5.15-9.13) (5.60-10.6) 4-day 1.05 1.59 2.33 2.95 3.85 4.57 5.34 6.16 7.32 8.27 (0 932-1 21) (1.41-183) (2.05--269) (2 59.3 44) (3 26-4.63) (3.80,5.62) (4.33,6, 71) (4 86-7.96) (5.55,9,85) (6,00-)1.5 7-day 1.11 1.88 2.46 3.12 4.08 4.86 5.69 6.58 7.86
(0 984-1,20) (1 48-1.93) (2.17-2.84) (2. 74-3.64) (3.46-4.92) (4.04-5 97) (4,62-7.16) (5 20-8.50) (5.96-10 6) ( 10-day 1.12 1.70 2.49 3.17 4.15 4.95 5.80 6.71 8.02 9.10 /0 996-1.30\ 11.50-1,961 (2.20-2.8B l (2,78-3 70) 13.52--5.00) (4.1I-B,08) (4, 70-7.29) (5.30-8.67) (6.08-10 0) (6 67-12.7) i 20-day I 1.22
I 11.:/2
1 161 11 12.4\~I.211 I

3.55 4.87 I s.sa II 6.55 I 7.61 9.11 10.4
/1,08-1 41) (3.11-4.14) {3,96--5.62) : {4,64--8.86) :: \5.32-8.24) : (6.00,9.83) {6 9I-I2.Jl (7 59-14 4l 30-day 1.33 2.06 3.08 3.95 5.21 6.23 7.33 8.51 10.2 11.6 (1 18-1 53) (1.82-2,37) (2.71-3.56) (3 46-4.601 (4.42-6.27) (5. 1 8-7 .68) (5.94-9.21) (6.72-110) (7.73-13,7) (8.49-16.1 l ~ 1.47 2.32 3.48 4.48 5.93 7.10 8.35 9.69 11.6 13.2
(1 31-1 70) (2 ,05-2.67) (3.0J..403) (3 93.5 23) (502-7 13) (5 90-8.72) (6 77-10,5) (765-125) (8,80-15 6) (9,66-18.3) 60-day 1.64 2.60 3.93 5.07
I (5 ;/8°011 I

8.03 9.44 10.9 13.1 14.9
/1.46-1.89) (2,30-3,00) (3.47-4.64) (4.44-5.91) (6.67-9,86} (7 65-11,9} (8 64-14,2) (9 94-17 6) (10 9-20,7) 'Precipilation frequency (PF) eslimates in this table are based on frequency analysis of partial duralion 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%. Estimales at upper bounds are not checked againsl probable maximum precipilation (PMP) estimates and may be higher than currently valid PMP values Please refer to NOAA Alias 14 document for more information Back to Top
https://hdsc. nws.noaa.gov/hdsc/pfds/pfds _printpage.html ?st=ca&sta=04-9099&data=depth... 12/3/2019 Page 1085 of 1452 Preliminary Offsite Drainage Study for Ofland Twentynine Palms APN 0614-121-15
Job No.227523-0000210.00

APPENDIX II
• CivilD Rational Method – Existing Offsite
NIVIS

San Bernardino County Rational Hydrology Program
(Hydrology Manual Date - August 1986)
CIVILCADD/CIVILDESIGN Engineering Software, (c) 1989-2014 Version 9.0 Rational Hydrology Study Date: 02/14/24
------------------------------------------------------------------------ Program License Serial Number 6360
------------------------------------------------------------------------ ********* Hydrology Study Control Information ********** ------------------------------------------------------------------------ Rational hydrology study storm event year is 100.0
Computed rainfall intensity:

Storm year = 100.00 1 hour rainfall = 2.030 (In.)
Slope used for rainfall intensity curve b = 0.7000
Soil antecedent moisture condition (AMC) = 1
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 1.000 to Point/Station 2.000 **** INITIAL AREA EVALUATION ****
______________________________________________________________________ UNDEVELOPED (average cover) subarea
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
SCS curve number for soil(AMC 2) = 50.00
Adjusted SCS curve number for AMC 1 = 31.00
Pervious ratio(Ap) = 1.0000 Max loss rate(Fm)= 0.983(In/Hr) Initial subarea data:

Initial area flow distance = 1000.000(Ft.)
Top (of initial area) elevation = 2950.000(Ft.)
Bottom (of initial area) elevation = 2925.000(Ft.)
Difference in elevation = 25.000(Ft.)
Slope = 0.02500 s(%)= 2.50
TC = k(0.706)*[(length^3)/(elevation change)]^0.2
Initial area time of concentration = 23.400 min.

Rainfall intensity = 3.924(In/Hr) for a 100.0 year storm Effective runoff coefficient used for area (Q=KCIA) is C = 0.675 Subarea runoff = 26.469(CFS)
Total initial stream area = 10.000(Ac.)
Pervious area fraction = 1.000
Initial area Fm value = 0.983(In/Hr)

  
     
 

  
  
  
  

 
   

   
   


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Depth of flow = 0.926(Ft.), Average velocity = 5.113(Ft/s) End of computations, Total Study Area = 469.10 (Ac.)
The following figures may
be used for a unit hydrograph study of the same area.

Note: These figures do not consider reduced effective area effects caused by confluences in the rational equation.

Area averaged pervious area fraction(Ap) = 1.000
Area averaged SCS curve number = 61.4

Preliminary Offsite Drainage Study for Ofland Twentynine Palms APN 0614-121-15
Job No.227523-0000210.00

APPENDIX III
• Offsite Hydrology Map
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JOB NUMBER
227523-0000210
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42-629 COOK STREET, SUITE 104
PALM DESERT, CA 92211
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OFFSITE HYDROLOGY MAP
APN'S: 0614-121-15
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City of Twentynine Palms
Ofland Hotel Initial Study
G
APPENDIX G: Noise Study
Available on the City of Twentynine Palms Website:
www.ci.twentynine-palms.ca.us

Yonder 29 Palms

NOISE IMPACT ANALYSIS

CITY OF TWENTYNINE PALMS
PREPARED BY:

William Maddux
[email protected]
(619) 788-1971
JANUARY 11, 2024
15631-03 Noise Study.docx

Yonder 29 Palms Noise Impact Analysis
15631-03 Noise Study.docx
i

TABLEOF CONTENTS
TABLE OF CONTENTS ............................................................................................................................. I APPENDICES......................................................................................................................................... II LIST OF EXHIBITS .................................................................................................................................. II LIST OF TABLES.................................................................................................................................... III LIST OF ABBREVIATED TERMS .............................................................................................................. IV EXECUTIVE SUMMARY.......................................................................................................................... 1 1 INTRODUCTION........................................................................................................................... 3

1.1 Site Location.................................................................................................................................. 3

1.2 Project Description........................................................................................................................ 3 2 Fundamentals................................................................................................................................ 7

2.1 Range of Noise .............................................................................................................................. 7

2.2 Noise Descriptors.......................................................................................................................... 8

2.3 Sound Propagation........................................................................................................................ 8

2.4 Noise Control ..............................................................................................................................10

2.5 Noise Barrier Attenuation ...........................................................................................................10

2.6 Land Use Compatibility With Noise .............................................................................................10

2.7 Community Response to Noise ...................................................................................................10

2.8 Vibration .....................................................................................................................................11 3 REGULATORY SETTING................................................................................................................13

3.1 State of California Noise Requirements.......................................................................................13

3.2 City of Twentynine Palms General Plan.......................................................................................13

3.4 Construction Noise Standards. ....................................................................................................16

3.5 Construction Vibration Standards...............................................................................................17 4 SIGNIFICANCE CRITERIA..............................................................................................................19

4.1 CEQA Guidelines Not Further Analyzed.......................................................................................19

4.2 Noise-Sensitive Receivers............................................................................................................19

4.3 Significance Criteria Summary.....................................................................................................20 5 EXISTING NOISE LEVEL MEASUREMENTS.....................................................................................23

5.1 Measurement Procedure and Criteria.........................................................................................23

5.2 Noise Measurement Locations....................................................................................................23

5.3 Noise Measurement Results .......................................................................................................25 6 METHODS AND PROCEDURES. ....................................................................................................27

6.1 FHWA Traffic Noise Prediction Model.........................................................................................27 7 ON-SITE TRAFFIC NOISE IMPACTS ...............................................................................................29

7.1 On-Site Exterior Noise Analysis....................................................................................................29

7.2 On-Site Interior Noise Analysis....................................................................................................29 8 OFF-SITE TRAFFIC NOISE ANALYSIS..............................................................................................31 9 SENSITIVE RECEIVER LOCATIONS................................................................................................. 33

Yonder 29 Palms Noise Impact Analysis
15631-03 Noise Study.docx
ii
10 OPERATIONAL NOISE IMPACTS ...................................................................................................35

10.1 Operational Noise Sources..........................................................................................................35

10.2 Reference Noise Levels................................................................................................................35

10.4 Project Operational Noise Levels................................................................................................. 39

10.5 Project Operational Noise Level Compliance...............................................................................40

10.6 Project Operational Noise Level Increases ..................................................................................41 11 CONSTRUCTION IMPACTS...........................................................................................................43

11.1 Construction Noise Levels...........................................................................................................43

11.2 Typical Construction Reference Noise Levels ..............................................................................43

11.3 Construction Noise Analysis........................................................................................................45

11.4 Construction Noise Level Compliance .........................................................................................46

11.5 Construction Vibration Impacts...................................................................................................46 12 REFERENCES ...............................................................................................................................49 13 CERTIFICATION...........................................................................................................................51

APPENDICES
APPENDIX 3.1: CITY OF TWENTYNINE PALMS DEVELOPMENT CODE APPENDIX 5.1: STUDY AREA PHOTOS
APPENDIX 5.2: NOISE LEVEL MEASUREMENT WORKSHEETS
APPENDIX 7.1: ON-SITE TRAFFIC NOISE MODELING
APPENDIX 10.1: SAMPLE AIR CONDITIONER MANUFACTURERS SPECIFICATION SHEETS APPENDIX 10.2: CADNAA OPERATIONAL NOISE MODEL INPUTS
APPENDIX 11.1: CADNAA CONSTRUCTION NOISE LEVEL CALCULATIONS

LIST OF EXHIBITS
EXHIBIT 1-A: LOCATION MAP............................................................................................................... 4 EXHIBIT 1-B: SITE PLAN........................................................................................................................ 5 EXHIBIT 2-A: TYPICAL NOISE LEVELS..................................................................................................... 7 EXHIBIT 2-B: NOISE LEVEL INCREASE PERCEPTION...............................................................................11 EXHIBIT 2-C: TYPICAL LEVELS OF GROUND-BORNE VIBRATION ............................................................12 EXHIBIT 3-A: CITY OF TWENTYNINE PALMS NOISE/LAND USE COMPATIBILITY MATRIX........................15 EXHIBIT 5-A: NOISE MEASUREMENT LOCATIONS.................................................................................24 EXHIBIT 9-A: SENSITIVE RECEIVER LOCATIONS.....................................................................................34 EXHIBIT 10-A: OPERATIONAL NOISE SOURCE LOCATIONS.....................................................................36 EXHIBIT 11-A: CONSTRUCTION NOISE ACTIVITY...................................................................................44

Yonder 29 Palms Noise Impact Analysis
15631-03 Noise Study.docx
iii

LIST OF TABLES
TABLE ES-1: SUMMARY OF CEQA SIGNIFICANCE FINDINGS .................................................................. 1 TABLE 3-1: NOISE LEVEL STANDARDS ................................................................................................. 16 TABLE 4-1: SIGNIFICANCE CRITERIA SUMMARY .................................................................................. 21 TABLE 5-1: 24-HOUR AMBIENT NOISE LEVEL MEASUREMENTS .......................................................... 25 TABLE 6-1: ON-SITE ROADWAY PARAMETERS ................................................................................... 27 TABLE 6-2: TIME OF DAY VEHICLE SPLITS ........................................................................................... 28 TABLE 6-3: DISTRIBUTION OF TRAFFIC FLOW BY VEHICLE TYPE (VEHICLE MIX) ................................... 28 TABLE 10-1: REFERENCE NOISE LEVEL MEASUREMENTS .................................................................... 37 TABLE 10-2: DAYTIME PROJECT OPERATIONAL NOISE LEVELS ............................................................. 40 TABLE 10-3: NIGHTTIME PROJECT OPERATIONAL NOISE LEVELS ......................................................... 40 TABLE 10-4: DAILY PROJECT OPERATIONAL NOISE LEVELS .................................................................. 40 TABLE 10-5: OPERATIONAL NOISE LEVEL COMPLIANCE ...................................................................... 41 TABLE 10-5: DAYTIME PROJECT OPERATIONAL NOISE LEVEL INCREASES ............................................ 42 TABLE 10-6: NIGHTTIME OPERATIONAL NOISE LEVEL INCREASES ....................................................... 42 TABLE 11-1: CONSTRUCTION REFERENCE NOISE LEVELS .................................................................... 45 TABLE 11-2: CONSTRUCTION EQUIPMENT NOISE LEVEL SUMMARY ................................................... 46 TABLE 11-3: CONSTRUCTION NOISE LEVEL COMPLIANCE ................................................................... 46 TABLE 11-4: VIBRATION SOURCE LEVELS FOR CONSTRUCTION EQUIPMENT ...................................... 47 TABLE 11-5: PROJECT CONSTRUCTION VIBRATION LEVELS ................................................................. 48

Yonder 29 Palms Noise Impact Analysis
15631-03 Noise Study.docx
iv

LIST OF ABBREVIATED TERMS
(1) Reference
ADT Average Daily Traffic
ANSI American National Standards Institute
Calveno California Vehicle Noise
CEQA California Environmental Quality Act
CNEL Community Noise Equivalent Level
dBA A-weighted decibels
EPA Environmental Protection Agency
FHWA Federal Highway Administration
FTA Federal Transit Administration
INCE Institute of Noise Control Engineering
Leq Equivalent continuous (average) sound level
Lmax Maximum level measured over the time interval
Lmin Minimum level measured over the time interval
mph Miles per hour
OPR Office of Planning and Research
PPV Peak particle velocity
Project Yonder 29 Palms
REMEL Reference Energy Mean Emission Level
RMS Root-mean-square
VdB Vibration Decibels

Yonder 29 Palms Noise Impact Analysis
15631-03 Noise Study.docx
1 EXECUTIVE SUMMARY
Urban Crossroads, Inc. has prepared this noise study to determine the potential noise impacts and the necessary noise mitigation measures, if any, for Yonder 29 Palms development (“Project”). The proposed Project consist of resort operating 24 hours a day with food and beverage services. The Project is anticipated to have up to 130-rooms. This study has been prepared to satisfy applicable City of Twentynine Palms standards and thresholds of significance based on guidance provided by Appendix G of the California Environmental Quality Act (CEQA) Guidelines. (1)
The results of this Yonder 29 Palms Noise Impact Analysis are summarized below based on the significance criteria in Section 4 of this report. Table ES-1 shows the findings of significance for each potential noise and/or vibration impact under CEQA before and after any required mitigation measures.

TABLE ES-1: SUMMARY OF CEQA SIGNIFICANCE FINDINGS
Analysis Report
Section
Significance Findings
Unmitigated Mitigated
On-Site Traffic Noise 7 Less Than Significant -
Off-Site Traffic Noise 8 Less Than Significant -
Operational Noise 10 Less Than Significant -
Construction Noise
11 Less Than Significant -
Construction Vibration Less Than Significant -

Yonder 29 Palms Noise Impact Analysis
15631-03 Noise Study.docx
2 This page intentionally left blank

Yonder 29 Palms Noise Impact Analysis
15631-03 Noise Study.docx
3 1 INTRODUCTION
This noise analysis has been completed to determine the noise impacts associated with the development of Yonder 29 Palms (“Project”). This noise study briefly describes the proposed Project, provides information regarding noise fundamentals, outlines the local regulatory setting, provides the study methods and procedures for performing noise analysis, evaluates potential noise impacts from the project, and identifies mitigation measures to reduce impacts, as necessary.

1.1 SITE LOCATION
The Yonder 29 Palms Project is located on the southeast corner of Twentynine Palms Highway and Lear Avenue in the City of Twentynine Palms, as shown on Exhibit 1-A. The Project is located immediately south of Highway 62.

1.2 PROJECT DESCRIPTION
A preliminary site plan for the proposed Project is shown on Exhibit 1-B. The Project is proposed to consist of the development of a 150-acre glamping resort with a total of 130 units. Each room will be roughly 28 feet in length by 12 feet in width with a covered patio of equal dimensions.

Additional amenities include food & beverage space, and a main lodge that could host special events. The main lodge will be 3,500 square feet that will operate as a retail space and resort lobby. Adjacent to the main lodge will be a separate feet food and beverage space of approximately 2,000 square feet. The main lodge area includes a fenced-in swimming pool and hot tub area. A 2,000 square foot secondary lodge with gathering areas and an outdoor patio surrounding a fenced-in pool will be located in the southeastern quadrant of the site. The Main Lodge, Food and Beverage Space, and Secondary Lodge will be open from 6:00 a.m. to 10:00 p.m.

The engineering, maintenance equipment, and laundry facilities for operations will be located in the back-of-house area comprised of three buildings totaling 6,000 square feet in the southern western quadrant of the site. Employee housing structures will be provided within four structures, approximately 12,000 square feet. An outdoor movie Screen is planned near the main lodge. This screen will be approximately 16 feet tall with a seating area and would play familyfriendly movies. The Project site is shown on Exhibit 1-A.

The on-site Project-related noise sources are expected to include air conditioning units, outdoor activities, music, an outdoor movie screen, trash enclosure activity, and parking lot activity.

According to the project applicant, soft ambient background music will be played in the main and secondary lodge areas throughout the day from 6:00 a.m. to 10:00 p.m. on small satellite speakers. The outdoor movie screen will play family-friendly entertainment with the start and end times dependent on sunset. The audio for the outdoor movie area is broadcasted by personal FM radios or mobile apps. No central loudspeakers will be used on-site. This noise analysis is intended to describe noise level impacts associated with the expected typical operational activities at the Project site.

Yonder 29 Palms Noise Impact Analysis
15631-03 Noise Study.docx
4 EXHIBIT 1-A: LOCATION MAP
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Yonder 29 Palms Noise Impact Analysis
15631-03 Noise Study.docx
5 EXHIBIT 1-B: SITE PLAN
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Yonder 29 Palms Noise Impact Analysis
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Yonder 29 Palms Noise Impact Analysis
15631-03 Noise Study.docx
7 2 FUNDAMENTALS
Noise is simply defined as "unwanted sound." Sound becomes unwanted when it interferes with normal activities, when it causes actual physical harm or when it has adverse effects on health.

Noise is measured on a logarithmic scale of sound pressure level known as a decibel (dB). Aweighted decibels (dBA) approximate the subjective response of the human ear to broad frequency noise source by discriminating against very low and very high frequencies of the audible spectrum. They are adjusted to reflect only those frequencies which are audible to the human ear. Exhibit 2-A presents a summary of the typical noise levels and their subjective loudness and effects that are described in more detail below.

EXHIBIT 2-A: TYPICAL NOISE LEVELS

2.1 RANGE OF NOISE
Since the range of intensities that the human ear can detect is so large, the scale frequently used to measure intensity is a scale based on multiples of 10, the logarithmic scale. The scale for measuring intensity is the decibel scale. Each interval of 10 decibels indicates a sound energy ten times greater than before, which is perceived by the human ear as being roughly twice as loud. (2) The most common sounds vary between 40 dBA (very quiet) to 100 dBA (very loud). Normal conversation at three feet is roughly at 60 dBA, while loud jet engine noises equate to 110 dBA at approximately 100 feet, which can cause serious discomfort. (3) Another important aspect of noise is the duration of the sound and the way it is described and distributed in time.

COMMON OUTDOOR COMMON INDOOR A· WEIGHTED
ACTIVITIES ACTIVITIES SOUND LEVEL dBA
THRESHOLD OF PAIN 140
NEAR JET ENGINE 130
120
JET FLY-OVER AT 300m (1000 ft) ROCK BAND 110
LOUD AUTO HORN 100
GAS LAWN MOWER AT 1m (3 ft) 90
\flRYNotsY
DIESEL TRUCK AT 15m (50 ft), FOOD BLENDER AT 1m (3 ft) 80 at BO km/hr (50 mph) NOISY URBAN AREA, DAYTIME VACUUM CLEANER AT 3m (10 ft) 70 SPEECH

LOUD INTERFERENCE
HEAVY TRAFFIC AT 90m (300ft) NORMAL SPEECH AT 1m (3 ft) 60 QUIET URBAN DAYTIME LARGE BUSINESS OFFICE so

MODERATE SLEEP
QUIET URBAN NIGHmME THEATER, LARGE CONFERENCE 40 DISTURBANCE

ROOM (BACKGROUND)
QUIET SUBURBAN NIGHTTIME LIBRARY 30

BEDROOM AT NIGHT, CONCERT FAINT
QUIET RURAL NIGHmME liALL (BACKGROUND) 20

NO EFFECT
BROADCAST/RECORDING 10 STUDIO

VERY FAINT
LOWEST THRESHOLD OF HUMAN LOWEST THRESHOLD OF HUMAN 0

HEARING HEARING

Yonder 29 Palms Noise Impact Analysis
15631-03 Noise Study.docx
8 2.2 NOISE DESCRIPTORS
Environmental noise descriptors are generally based on averages, rather than instantaneous, noise levels. The most used figure is the equivalent level (Leq). Equivalent sound levels are not measured directly but are calculated from sound pressure levels typically measured in Aweighted decibels (dBA). The equivalent sound level (Leq) represents a steady state sound level containing the same total energy as a time varying signal over a given sample period (typically one hour) and is commonly used to describe the “average” noise levels within the environment.

To describe the time-varying character of environmental noise, the statistical or percentile noise descriptors L50, L25, L8 and L2, are commonly used. The percentile noise descriptors are the noise levels equaled or exceeded during 50 percent, 25 percent, 8 percent and 2 percent of a stated time. Sound levels associated with the L2 and L8 typically describe transient or short-term events, while levels associated with the L50 describe the steady state (or median) noise conditions. The relies on the percentile noise levels to describe the stationary source noise level limits. While the L50 describes the noise levels occurring 50 percent of the time, the Leq accounts for the total energy (average) observed for the entire hour.

Peak hour or average noise levels, while useful, do not completely describe a given noise environment. Noise levels lower than peak hour may be disturbing if they occur during times when quiet is most desirable, namely evening and nighttime (sleeping) hours. To account for this, the Community Noise Equivalent Level (CNEL), representing a composite 24-hour noise level is utilized. The CNEL is the weighted average of the intensity of a sound, with corrections for time of day, and averaged over 24 hours. The time-of-day corrections require the addition of 5 decibels to dBA Leq sound levels in the evening from 7:00 p.m. to 10:00 p.m., and the addition of 10 decibels to dBA Leq sound levels at night between 10:00 p.m. and 7:00 a.m. These additions are made to account for the noise sensitive time periods during the evening and night hours when sound appears louder. CNEL does not represent the actual sound level heard at any time, but rather represents the total sound exposure. The City of Twentynine Palms relies on the 24- hour CNEL level to assess land use compatibility with transportation related noise sources.

2.3 SOUND PROPAGATION
When sound propagates over a distance, it changes in level and frequency content. The way noise reduces with distance depends on the following factors.

2.3.1 GEOMETRIC SPREADING
Sound from a localized source (i.e., a stationary point source) propagates uniformly outward in a spherical pattern. The sound level attenuates (or decreases) at a rate of 6 dB for each doubling of distance from a point source. Highways consist of several localized noise sources on a defined path and hence can be treated as a line source, which approximates the effect of several point sources. Noise from a line source propagates outward in a cylindrical pattern, often referred to as cylindrical spreading. Sound levels attenuate at a rate of 3 dB for each doubling of distance from a line source. (2)

Yonder 29 Palms Noise Impact Analysis
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9 2.3.2 GROUND ABSORPTION
The propagation path of noise from a highway to a receiver is usually very close to the ground.

Noise attenuation from ground absorption and reflective wave canceling adds to the attenuation associated with geometric spreading. Traditionally, the excess attenuation has also been expressed in terms of attenuation per doubling of distance. This approximation is usually sufficiently accurate for distances of less than 200 ft. For acoustically hard sites (i.e., sites with a reflective surface between the source and the receiver, such as a parking lot or body of water), no excess ground attenuation is assumed. For acoustically absorptive or soft sites (i.e., those sites with an absorptive ground surface between the source and the receiver such as soft dirt, grass, or scattered bushes and trees), an excess ground attenuation value of 1.5 dB per doubling of distance is normally assumed. When added to the cylindrical spreading, the excess ground attenuation results in an overall drop-off rate of 4.5 dB per doubling of distance from a line source. (4)

2.3.3 ATMOSPHERIC EFFECTS
Receivers located downwind from a source can be exposed to increased noise levels relative to calm conditions, whereas locations upwind can have lowered noise levels. Sound levels can be increased at large distances (e.g., more than 500 feet) due to atmospheric temperature inversion (i.e., increasing temperature with elevation). Other factors such as air temperature, humidity, and turbulence can also have significant effects. (2)

2.3.4 SHIELDING
A large object or barrier in the path between a noise source and a receiver can substantially attenuate noise levels at the receiver. The amount of attenuation provided by shielding depends on the size of the object and the frequency content of the noise source. Shielding by trees and other such vegetation typically only has an “out of sight, out of mind” effect. That is, the perception of noise impact tends to decrease when vegetation blocks the line-of-sight to nearest residents. However, for vegetation to provide a substantial, or even noticeable, noise reduction, the vegetation area must be at least 15 feet in height, 100 feet wide and dense enough to completely obstruct the line-of sight between the source and the receiver. This size of vegetation may provide up to 5 dBA of noise reduction. The Federal Highway Administration (FHWA) does not consider the planting of vegetation to be a noise abatement measure. (4)

2.3.5 REFLECTION
Field studies conducted by the FHWA have shown that the reflection from barriers and buildings does not substantially increase noise levels. (4) If all the noise striking a structure was reflected back to a given receiving point, the increase would be theoretically limited to 3 dBA. Further, not all the acoustical energy is reflected back to same point. Some of the energy would go over the structure, some is reflected to points other than the given receiving point, some is scattered by ground coverings (e.g., grass and other plants), and some is blocked by intervening structures and/or obstacles (e.g., the noise source itself). Additionally, some of the reflected energy is lost due to the longer path that the noise must travel. FHWA measurements made to quantify

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10 reflective increases in traffic noise have not shown an increase of greater than 1-2 dBA; an increase that is not perceptible to the average human ear.

2.4 NOISE CONTROL
Noise control is the process of obtaining an acceptable noise environment for an observation point or receiver by controlling the noise source, transmission path, receiver, or all three. This concept is known as the source-path-receiver concept. In general, noise control measures can be applied to these three elements.

2.5 NOISE BARRIER ATTENUATION
Effective noise barriers can reduce noise levels by up to 10 to 15 dBA, cutting the loudness of traffic noise in half. A noise barrier is most effective when placed close to the noise source or receiver. Noise barriers, however, do have limitations. For a noise barrier to work, it must be high enough and long enough to block the path of the noise source. (4)

2.6 LAND USE COMPATIBILITY WITH NOISE
Some land uses are more tolerant of noise than others. For example, schools, hospitals, churches, and residences are more sensitive to noise intrusion than are commercial or industrial developments and related activities. As ambient noise levels affect the perceived amenity or livability of a development, so too can the mismanagement of noise impacts impair the economic health and growth potential of a community by reducing the area’s desirability as a place to live, shop and work. For this reason, land use compatibility with the noise environment is an important consideration in the planning and design process. The FHWA encourages State and Local government to regulate land development in such a way that noise-sensitive land uses are either prohibited from being located adjacent to a highway, or that the developments are planned, designed, and constructed in such a way that noise impacts are minimized. (5)

2.7 COMMUNITY RESPONSE TO NOISE
Community responses to noise may range from registering a complaint by telephone or letter, to initiating court action, depending upon everyone’s susceptibility to noise and personal attitudes about noise. Several factors are related to the level of community annoyance including:
 Fear associated with noise producing activities;
 Socio-economic status and educational level;
 Perception that those affected are being unfairly treated;  Attitudes regarding the usefulness of the noise-producing activity;  Belief that the noise source can be controlled.

Approximately ten percent of the population has a very low tolerance for noise and will object to any noise not of their making. Consequently, even in the quietest environment, some complaints will occur. Twenty-five percent of the population will not complain even in very severe noise environments. Thus, a variety of reactions can be expected from people exposed to any given noise environment. (6) Surveys have shown that about ten percent of the people exposed to

Yonder 29 Palms Noise Impact Analysis
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11 traffic noise of 60 dBA will report being highly annoyed with the noise, and each increase of one dBA is associated with approximately two percent more people being highly annoyed. When traffic noise exceeds 60 dBA or aircraft noise exceeds 55 dBA, people may begin to complain. (6) Despite this variability in behavior on an individual level, the population can be expected to exhibit the following responses to changes in noise levels as shown on Exhibit 2-B. A change of 3 dBA are considered barely perceptible, and changes of 5 dBA are considered readily perceptible. (4)
EXHIBIT 2-B: NOISE LEVEL INCREASE PERCEPTION

2.8 VIBRATION
As defined in the Federal Transit Administration (FTA) Transit Noise and Vibration Impact Assessment Manual (7) and the California Department of Transportation (Caltrans) Transportation and Construction Vibration Guidance Manual (8), vibration is the periodic oscillation of a medium or object. The rumbling sound caused by the vibration of room surfaces is called structure-borne noise. Sources of ground-borne vibrations include natural phenomena (e.g., earthquakes, volcanic eruptions, sea waves, landslides) or human-generated sources (e.g., explosions, machinery, traffic, trains, construction equipment). Vibration sources may be continuous, such as factory machinery, or transient, such as explosions or train pass-byes. As is the case with airborne sound, ground-borne vibrations may be described by amplitude and frequency. Groundborne vibration is primarily a concern inside structures, and is almost never a problem outside of structures (7). Additionally, ground-borne vibration generated by man-made activities typically attenuates rapidly with distance from the source of the vibration. Sensitive receivers for vibration include older stone, adobe, and masonry structures, places where people reside (especially residents, the elderly, and sick), and vibration-sensitive equipment and/or activities.

There are several different methods that are used to quantify vibrations. The peak particle velocity (PPV) in inches per second (in/sec) is the most common and is defined as the maximum instantaneous peak of the vibration signal. The PPV is the was developed primarily to describe vibration impacts to buildings and is not always the most suitable for evaluating human response to vibration because it takes some time for the human body to respond to vibration signals.

Instead, the human body responds to average vibration amplitude often described as the root mean square (RMS) amplitude in in/sec. The RMS amplitude is defined as the average of the squared amplitude of the signal and may be more appropriate for describing the effect of 0 1 2 3 4 5 6 7 8 9 10
Just Perceptible
Barely Perceptible
Readily Perceptible
Twice as Loud
Noise Level Increase (dBA)

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12 vibration on the human body. However, the RMS amplitude and PPV are related mathematically, and the RMS amplitude can be calculated from the PPV. The RMS amplitude is approximately 70% of the PPV (8).

While not universally accepted, vibration decibel notation (VdB) is used by the FTA in their guidance manual to describe vibration levels and provide a background of common vibration levels (9). As stated in the FTA guidance manual, the background vibration-velocity level in residential areas is generally 50 VdB. Ground-borne vibration is normally perceptible to humans at approximately 65 VdB. For most people, a vibration-velocity level of 75 VdB is the approximate dividing line between barely perceptible and distinctly perceptible levels. Typical outdoor sources of perceptible ground-borne vibration are construction equipment, steel-wheeled trains, and traffic on rough roads. If a roadway is smooth, the ground-borne vibration is rarely perceptible. The range of interest is from approximately 50 VdB, which is the typical background vibration-velocity level, to 100 VdB, which is the general threshold where minor damage can occur in fragile buildings. Exhibit 2-C illustrates common vibration sources and the human and structural response to ground-borne vibration.

EXHIBIT 2-C: TYPICAL LEVELS OF GROUND-BORNE VIBRATION
Source: Federal Transit Administration (FTA) Transit Noise and Vibration Impact Assessment Manual.

Human/Structural Response
Threshold, minor cosmetic damage
fragile buildings
Difficulty with tasks such as
reading a VDT screen
Residential annoyance, infrequent -
events (e.g. commuter rail)
Residential annoyance, frequent -
events (e.g. rapid transit)
Limit for vibration sensitive
equipment. Approx. threshold for
human perception of vibration
Velocity
Level*
50 Typical Sources
(50 ft from source)
Blasting from construction projects
Bulldozers and other heavy tracked
construction equipment
Commuter rail, upper range
Rapid transit, upper range
Commuter rail, typical
Bus or truck over bump
Rapid transit, typical
Bus or truck, typlcal
Typtcal background vibration
• RMS Vibration Velocity Level in VdB relative to 10-6 inches/second

Yonder 29 Palms Noise Impact Analysis
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13 3 REGULATORY SETTING
To limit population exposure to physically and/or psychologically damaging as well as intrusive noise levels, the federal government, the State of California, various county governments, and most municipalities in the state have established standards and ordinances to control noise. In most areas, automobile and truck traffic is the major source of environmental noise. Traffic activity generally produces an average sound level that remains constant with time. Air and rail traffic, and commercial and industrial activities are also major sources of noise in some areas.

Federal, state, and local agencies regulate different aspects of environmental noise. Federal and state agencies generally set noise standards for mobile sources such as aircraft and motor vehicles, while regulation of stationary sources is left to local agencies.

3.1 STATE OF CALIFORNIA NOISE REQUIREMENTS
The State of California regulates freeway noise, sets standards for sound transmission, provides occupational noise control criteria, identifies noise standards, and provides guidance for local land use compatibility. State law requires that each county and city adopt a General Plan that includes a Countywide Plan which is to be prepared per guidelines adopted by the Governor’s Office of Planning and Research (OPR). (10) The purpose of the Countywide Plan is to limit the exposure of the community to excessive noise levels. In addition, the California Environmental Quality Act (CEQA) requires that all known environmental effects of a project be analyzed, including environmental noise impacts.

3.2 CITY OF TWENTYNINE PALMS GENERAL PLAN
The General Plan is a tool for managing noise by planning for and maintaining compatibility between sensitive land uses and noise sources. (11) The Noise Element of the General Plan includes the following goal and implementation policies: (12) Goal NS-1: Noise levels will be addressed prior to the City taking actions on land use proposals and potential conflicts will be avoided or mitigated so that noise levels will not exceed acceptable levels.

Implementation Policies
NS-1.1: Noise generation impacts will be considered prior to any land use designation change and/or any land use intensification and uses will be located in a manner that minimizes noise impacts. Prior to approval of projects, which may result in significant noise pollution, the City will require noise analysis to ensure that noise levels do not exceed acceptable levels as defined by the City’s Development Code.

The City will require special design standards for proposed projects with the potential to exceed the noise level requirements. In cases where special design standards are required, the City will require mitigation plans to be certified by a registered acoustician.

NS-1.2: The City will limit the establishment of land uses in the Twentynine Palms Airport flight pattern that would result in noise conflicts.

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14 NS-1.3: Develop a buyer and renter notification program for the persons within the City limits locating under the Sundance Military Operations Area (MOA) airspace. This area experiences occasional high levels of aircraft activity and is bounded roughly by the Marine Base to the north, Indian Trail on the south, Canyon Road on the west and past the limits of the City to the east. The notification program should simply inform persons and businesses moving into that area that they will be exposed to occasional high levels of aircraft activity.

NS-1.4: Require all exterior noise sources (construction operations, air compressors, pumps, fans and leaf blowers) to use available noise suppression devices and techniques to bring exterior noise down to acceptable levels, as defined by the City’s Development Code, that are compatible with adjacent land uses.

NS-1.5: Develop a buyer and renter notification program for the persons within the City limits that are determined to be affected by other noise generating uses on the Marine Base. The program shall include measurements of these occasional noise occurrences from other noise generating uses to determine the area impacted.

The notification program should simply inform persons and businesses moving into that area that they will be exposed to occasional high levels of noise.

3.3.1 LAND USE COMPATIBILITY
The noise criteria identified in the City of Twentynine Palms Noise Element (Table 4) are guidelines to evaluate the land use compatibility of transportation-related noise. The compatibility criteria, shown on Exhibit 3-A, provides the City with a planning tool to gauge the compatibility of land uses relative to existing and future exterior noise levels.

The Land Use and Noise Compatibility Matrix describes categories of compatibility and not specific noise standards. The transient lodging land uses of the Project are considered clearly compatible with unmitigated exterior noise levels of less than 65 dBA CNEL and normally compatible with unmitigated exterior noise levels approaching 70 dBA CNEL, new construction or development should be undertaken only after detailed analysis of the noise reduction requirements are made and needed noise insulation features in the design are determined.

Conventional construction, with closed windows and fresh air supply systems or air conditioning, will normally suffice. For normally incompatible exterior noise levels, exceeding 80 dBA CNEL, new construction or development should be discouraged. If new construction or development does proceed, a detailed analysis of the noise reduction requirements are made and needed noise insulation features must be included in the design.

3.3 CITY OF TWENTYNINE PALMS DEVELOPMENT CODE
While the City of Twentynine Palms Noise Element provides guidelines and criteria to assess transportation noise on sensitive land uses, the County Code, Title 19 Development Code, Article 4 Site Development Regulations, Chapter 19.80 Noise Control contains the general noise regulation, noise level limits for various land uses from all noise sources, interior noise level limits, prohibitions, and vibration standards. (13)

Yonder 29 Palms Noise Impact Analysis
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15 EXHIBIT 3-A: CITY OF TWENTYNINE PALMS NOISE/LAND USE COMPATIBILITY MATRIX Source: City of Twentynine Palms General Plan, Noise Element, Exhibit NS-9.

3.3.2 OPERATIONAL NOISE STANDARDS
To analyze noise impacts originating from a designated fixed location or private property such as the Yonder 29 Palms Project, stationary-source (operational) noise such as the expected air conditioning units, outdoor activities, music, an outdoor movie screen, trash enclosure activity, and parking lot activity are typically evaluated against standards established under a jurisdiction’s Municipal Code. The City of Twentynine Palms County Code, Title 19 Development Code, Section

19.80.070(a) establishes the noise level standards for noise sources. Since the Project’s land use will potentially impact adjacent noise-sensitive uses in the Project study area, this noise study '1fl UuC Ill r,
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Yonder 29 Palms Noise Impact Analysis
15631-03 Noise Study.docx
16 relies on the more conservative residential noise level standards to describe potential operational noise impacts.

For residential properties, the exterior noise level shall not exceed 65 dBA CNEL. (13) Further, Section 19.80.070(c) indicates that if the existing ambient noise level already exceeds any of the exterior noise level limit categories, then the standard shall be adjusted by 5 dBA to reflect the ambient conditions. The City of Twentynine Palms noise level standards are shown on Table 3-1 and included in Appendix 3.1.

TABLE 3-1: NOISE LEVEL STANDARDS
Affected Land Use (Receiving Noise)
Noise Level
Interior CNEL Exterior CNEL
Residential Districts (RL, RS, RM, R-HD, OSR) 45 dBA 65dBA Residential within Mixed Use
30 dBA Outdoor
to Indoor Noise
Reduction
-
Office Commercial District (CO)and Public District (P) 45 dBA - Other Commercial Districts (CN, CG, CT, CS) 45 dBA -
Community Industrial (IC) 70 dBA -
Open Space - 65 dBA
Military (M)
As determined
by Base
Command
-
City of Twentynine Palms Muncipal Code Chapter 19.80.070(A)

3.4 CONSTRUCTION NOISE STANDARDS
Section 19.80.100 of the City of Twentynine Palms Development Code, provided in Appendix 3.1, indicates that construction activity is considered exempt from the noise level standards between the hours of 7:00 a.m. to 7:00 p.m. except on Sundays and Federal holidays. (13) However, neither the City of Twentynine Palms General Plan or Municipal Code establish numeric maximum acceptable construction source noise levels at potentially affected receivers, which would allow for a quantified determination of what CEQA constitutes a substantial temporary or periodic noise increase. Therefore, a numerical construction threshold based on Federal Transit Administration (FTA) Transit Noise and Vibration Impact Assessment Manual is used for analysis of daytime construction impacts, as discussed below.

According to the FTA, local noise ordinances are typically not very useful in evaluating construction noise. They usually relate to nuisance and hours of allowed activity, and sometimes specify limits in terms of maximum levels, but are generally not practical for assessing the impact of a construction project. Project construction noise criteria should account for the existing noise environment, the absolute noise levels during construction activities, the duration of the construction, and the adjacent land use. Due to the lack of standardized construction noise thresholds, the FTA provides guidelines that can be considered reasonable criteria for

Yonder 29 Palms Noise Impact Analysis
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17 construction noise assessment. The FTA considers a daytime exterior construction noise level of 80 dBA Leq as a threshold for noise sensitive residential land use, a noise level of 85 dBA Leq for commercial locations, and 90 dBA Leq for industrial locations. (7)

3.5 CONSTRUCTION VIBRATION STANDARDS
Construction activity can result in varying degrees of ground-borne vibration, depending on the equipment and methods used, distance to the affected structures and soil type. Construction vibration is generally associated with pile driving and rock blasting. Other construction equipment such as air compressors, light trucks, hydraulic loaders, etc., generates little or no ground vibration. (7)
The City of Twentynine Palms Development Code, Chapter 19.80.100(a) states that vibration shall be no greater than or equal to two-tenths inches per second measured at or beyond the lot line. (13) Therefore, to determine if the vibration levels due to the operation and construction of the Project, the peak particle velocity (PPV) vibration level standard of 0.2 inches per second is used.

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19 4 SIGNIFICANCE CRITERIA
The following significance criteria are based on currently adopted guidance provided by Appendix G of the California Environmental Quality Act (CEQA) Guidelines. (10) For the purposes of this report, impacts would be potentially significant if the Project results in or causes:

A. Generation of a substantial temporary or permanent increase in ambient noise levels in the vicinity of the project in excess of standards established in the local general plan or noise ordinance, or applicable standards of other agencies?
B. Generation of excessive ground-borne vibration or ground-borne noise levels? C. For a project located within the vicinity of a private airstrip or an airport land use plan or, where such a plan has not been adopted, within two miles of a public airport or public use airport, would the project expose people residing or working in the project area to excessive noise levels? While the City of Twentynine Palms General Plan Guidelines provide direction on noise compatibility and establish noise standards by land use type that are sufficient to assess the significance of noise impacts, they do not define the levels at which increases are considered substantial for use under Guideline A. CEQA Appendix G Guideline C applies to nearby public and private airports, if any, and the Project’s land use compatibility.

4.1 CEQAGUIDELINES NOT FURTHER ANALYZED
The Project site is not located within two miles of a public airport or within an airport land use plan. The closest airport is Twentynine Palms Airport located approximately 10.8 miles east of the Project site. As such, the Project site would not be exposed to excessive noise levels from airport operations, and therefore, impacts are considered less than significant, and no further noise analysis is conducted in relation to CEQA Appendix G Guideline C.

4.2 NOISE-SENSITIVE RECEIVERS
Noise level increases resulting from the Project are evaluated based on the Appendix G CEQA Guidelines described above at the closest sensitive receiver locations. Under CEQA, consideration must be given to the magnitude of the increase, the existing ambient noise levels, and the location of noise-sensitive receivers to determine if a noise increase represents a significant adverse environmental impact. This approach recognizes that there is no single noise increase that renders the noise impact significant. (14) Unfortunately, there is no completely satisfactory way to measure the subjective effects of noise or of the corresponding human reactions of annoyance and dissatisfaction. This is primarily because of the wide variation in individual thresholds of annoyance and differing individual experiences with noise. Thus, an important way of determining a person’s subjective reaction to a new noise is the comparison of it to the existing environment to which one has adapted—the so-called ambient environment. In general, the more a new noise exceeds the previously existing ambient noise level, the less acceptable the new noise will typically be judged. The Federal Interagency Committee on Noise (FICON) (15) developed guidance to be used for the assessment

Yonder 29 Palms Noise Impact Analysis
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20 of project-generated increases in noise levels that consider the ambient noise level. The FICON recommendations are based on studies that relate aircraft noise levels to the percentage of persons highly annoyed by aircraft noise. Although the FICON recommendations were specifically developed to assess aircraft noise impacts, these recommendations are often used in environmental noise impact assessments involving the use of cumulative noise exposure metrics, such as the average-daily noise level (CNEL) and equivalent continuous noise level (Leq).

As previously stated, the approach used in this noise study recognizes that there is no single noise increase that renders the noise impact significant, based on a 2008 California Court of Appeal ruling on Gray v. County of Madera. (14) For example, if the ambient noise environment is quiet (<60 dBA) and the new noise source greatly increases the noise levels, an impact may occur if the noise criteria may be exceeded. Therefore, for this analysis, FICON identifies a readily perceptible 5 dBA or greater project-related noise level increase is considered a significant impact when the noise criteria for a given land use is exceeded. Per the FICON, in areas where the without project noise levels range from 60 to 65 dBA, a 3 dBA barely perceptible noise level increase appears to be appropriate for most people. When the without project noise levels already exceed 65 dBA, any increase in community noise louder than 1.5 dBA or greater is considered a significant impact if the noise criteria for a given land use is exceeded, since it likely contributes to an existing noise exposure exceedance.

The FICON guidance provides an established source of criteria to assess the impacts of substantial temporary or permanent increase in ambient noise levels. Based on the FICON criteria, the amount to which a given noise level increase is considered acceptable is reduced when the without Project noise levels are already shown to exceed certain land-use specific exterior noise level criteria. The specific levels are based on typical responses to noise level increases of 5 dBA or readily perceptible, 3 dBA or barely perceptible, and 1.5 dBA depending on the underlying without Project noise levels for noise-sensitive uses. These levels of increases and their perceived acceptance are consistent with guidance provided by both the Federal Highway Administration (4 p. 9) and Caltrans (16 p. 2_48).

4.3 SIGNIFICANCE CRITERIA SUMMARY
Noise impacts shall be considered significant if any of the following occur as a direct result of the proposed Project. Table 4-1 shows the significance criteria summary matrix.

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21 TABLE 4-1: SIGNIFICANCE CRITERIA SUMMARY
Analysis Land Use Condition(s) Significance Criteria
Daytime Nighttime
On-Site NoiseSensitive1 Noise Level Threshold See Exhibit 3-A Off-Site NoiseSensitive1
if ambient is < 60 dBA CNEL ≥ 5 dBA CNEL Project increase if ambient is 60 - 65 dBA CNEL ≥ 3 dBA CNEL Project increase if ambient is > 65 dBA CNEL ≥ 1.5 dBA CNEL Project increase Operational
Residential Exterior Noise Level Limit2
65 dBA CNEL
NoiseSensitive1
if ambient is < 60 dBA Leq ≥ 5 dBA Leq Project increase if ambient is 60 - 65 dBA Leq ≥ 3 dBA Leq Project increase if ambient is > 65 dBA Leq ≥ 1.5 dBA Leq Project increase Construction
All Permitted between 7:00 a.m. to 7:00 p.m.; except Sundays and Federal holidays.3
Residential
Noise Level Threshold4
80 dBA Leq n/a
Commercial 85 dBA Leq n/a
Industrial 90 dBA Leq n/a
All Vibration Level Threshold5 0.2 PPV in/sec n/a 1
FICON, 1992.
2 City of Twentynine Palms Development Code, Chapter 19.80.070 (Appendix 3.1) 3 City of Twentynine Palms Development Code, Chapter 19.80.090 (Appendix 3.1). 4 Federal Transit Administration, Transit Noise and Vibration Impact Assessment Manual. 5 City of Twentynine Palms Development Code, Chapter 19.80.100 (Appendix 3.1). "Daytime" = 7:00 a.m. to 10:00 p.m.; "Nighttime" = 10:00 p.m. to 7:00 a.m. "n/a" = construction activities are not planned during the nighttime hours; "PPV" = peak particle velocity.

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23 5 EXISTING NOISE LEVEL MEASUREMENTS
To assess the existing noise level environment, 24-hour noise level measurements were taken at four locations in the Project study area. The receiver locations were selected to describe and document the existing noise environment within the Project study area. Exhibit 5-A provides the boundaries of the Project study area and the noise level measurement locations. To fully describe the existing noise conditions, noise level measurements were collected by Urban Crossroads, Inc. on Friday, December 1, 2023. Appendix 5.1 includes study area photos.

5.1 MEASUREMENT PROCEDURE AND CRITERIA
To describe the existing noise environment, the hourly noise levels were measured during typical weekday conditions over a 24-hour period. By collecting individual hourly noise level measurements, it is possible to describe the daytime and nighttime hourly noise levels and calculate the 24-hour CNEL. The long-term noise readings were recorded using Piccolo Type 2 integrating sound level meter and dataloggers. The Piccolo sound level meters were calibrated using a Larson-Davis calibrator, Model CAL 150. All noise meters were programmed in "slow" mode to record noise levels in "A" weighted form. The sound level meters and microphones were equipped with a windscreen during all measurements. All noise level measurement equipment satisfies the American National Standards Institute (ANSI) standard specifications for sound level meters ANSI S1.4-2014/IEC 61672-1:2013. (17)

5.2 NOISE MEASUREMENT LOCATIONS
The long-term noise level measurements were positioned as close to the nearest sensitive receiver locations as possible to assess the existing ambient hourly noise levels surrounding the Project site. Both Caltrans and the FTA recognize that it is not reasonable to collect noise level measurements that can fully represent every part of a private yard, patio, deck, or balcony normally used for human activity when estimating impacts for new development projects. This is demonstrated in the Caltrans general site location guidelines which indicate that, sites must be free of noise contamination by sources other than sources of interest. Avoid sites located near sources such as barking dogs, lawnmowers, pool pumps, and air conditioners unless it is the express intent of the analyst to measure these sources. (2) Further, FTA guidance states, that it is not necessary nor recommended that existing noise exposure be determined by measuring at every noise-sensitive location in the project area. Rather, the recommended approach is to characterize the noise environment for clusters of sites based on measurements or estimates at representative locations in the community. (7)
Based on recommendations of Caltrans and the FTA, it is not necessary to collect measurements at each individual building or residence, because each receiver measurement represents a group of buildings that share acoustical equivalence. (7) In other words, the area represented by the receiver shares similar shielding, terrain, and geometric relationship to the reference noise source. Receivers represent a location of noise sensitive areas and are used to estimate the future noise level impacts.

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24 EXHIBIT 5-A: NOISE MEASUREMENT LOCATIONS
LEGEND:
[=] Site Boundary £ Measurement Locations

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25 Collecting reference ambient noise level measurements at the nearby sensitive receiver locations allows for a comparison of the before and after Project noise levels and is necessary to assess potential noise impacts due to the Project’s contribution to the ambient noise levels.

5.3 NOISE MEASUREMENT RESULTS
The noise measurements presented below focus on the average or equivalent sound levels (Leq).

The equivalent sound level (Leq) represents a steady state sound level containing the same total energy as a time varying signal over a given sample period. Table 5-1 identifies the hourly daytime (7:00 a.m. to 10:00 p.m.) and nighttime (10:00 p.m. to 7:00 a.m.) noise levels at each noise level measurement location.

TABLE 5-1: 24-HOUR AMBIENT NOISE LEVEL MEASUREMENTS
Location1 Description
Energy Average
Noise Level
(dBA Leq)
2 Daytime Nighttime
L1 Located west of the site near the residence at 69262 Cottonwood Drive 48.0 45.7
L2 Located northwest of the site near the residence at
6461 Monte Vista Ave. 63.3 60.5
L3 Located southeast of the site near the residence at
69711 Shoshone Valley Road 51.3 41.8
L4 Located northeast of the site near the residence at
6202 Twentynine Palms Highway 60.0 59.9
1 See Exhibit 5-A for the noise level measurement locations. 2 Energy (logarithmic) average levels. The long-term 24-hour measurement worksheets are included in Appendix 5.2. "Daytime" = 7:00 a.m. to 7:00 p.m.; "Nighttime" = 10:00 p.m. to 7:00 a.m.

Table 5-1 provides the (energy average) noise levels used to describe the daytime and nighttime ambient conditions. These daytime and nighttime energy average noise levels represent the average of all hourly noise levels observed during these time periods expressed as a single number. Appendix 5.2 provides summary worksheets of the noise levels for each hour as well as the minimum, maximum, L1, L2, L5, L8, L25, L50, L90, L95, and L99 percentile noise levels observed during the daytime and nighttime periods.

The background ambient noise levels in the Project study area are dominated by the transportation-related noise associated with surface streets in addition to background industrial land use activities. This includes the auto and heavy truck activities on study area roadway segments near the noise level measurement locations.

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27 6 METHODS AND PROCEDURES
The following section outlines the methods and procedures used to model and analyze the future traffic noise environment.

6.1 FHWA TRAFFIC NOISE PREDICTION MODEL
The estimated roadway noise impacts from vehicular traffic were calculated using a computer program that replicates the Federal Highway Administration (FHWA) Traffic Noise Prediction Model- FHWA-RD-77-108. (18) The FHWA Model arrives at a predicted noise level through a series of adjustments to the Reference Energy Mean Emission Level (REMEL). In California the national REMELs are substituted with the California Vehicle Noise (Calveno) Emission Levels. (19) Adjustments are then made to the REMEL to account for: the roadway classification (e.g., collector, secondary, major or arterial), the roadway active width (i.e., the distance between the center of the outermost travel lanes on each side of the roadway), the total average daily traffic (ADT), the travel speed, the percentages of automobiles, medium trucks, and heavy trucks in the traffic volume, the roadway grade, the angle of view (e.g., whether the roadway view is blocked), the site conditions ("hard" or "soft" relates to the absorption of the ground, pavement, or landscaping), and the percentage of total ADT which flows each hour throughout a 24-hour period.

ON-SITE TRAFFIC NOISE PREDICTION MODEL INPUTS
The on-site roadway parameters including the average daily traffic (ADT) volumes used for this study are presented on Table 6-1. To describe the future traffic conditions on I-15, existing traffic volumes were collected from the Annual Average Daily Truck Traffic (AADT) on the California Highway System, prepared by the Caltrans Traffic Data Branch, and an assumed growth rate of 10-percent was used to estimate future conditions. (20) The traffic volumes shown on Table 6-1 reflect future long-range traffic conditions needed to assess the future on-site traffic noise environment and to identify the appropriate noise mitigation measures, if any, that address the worst-case future conditions. Soft site conditions were used to analyze the traffic noise impacts within the Project study area which account for the sound propagation loss over natural surfaces such as normal earth and ground vegetation. Research conducted by Caltrans has shown that the use of soft site conditions is appropriate for the application of the FHWA traffic noise prediction model used in this noise study. (21)
TABLE 6-1: ON-SITE ROADWAY PARAMETERS
Roadway
Segment Lanes Classification1
Roadway
Capacity
Volume1
Speed
Limit
(mph)2
Site
Conditions
SR-62 4 State Route 25,300 55 Soft 1
Source: Caltrans, 2022 traffic counts at Joshua Tree Park Blvd. and SR-62, 2 percent annual growth for 20 years applied. 2 Posted speed limits.

I I I I I

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28 Table 6-2 presents the time-of-day vehicle splits by vehicle type, and Table 6-3 presents the total traffic flow distributions (vehicle mixes) used for this analysis. The vehicle mix provides the hourly distribution percentages of automobile, medium trucks, and heavy trucks for input into the FHWA Model based on roadway types. To predict the future noise environment at each building within the Project site, coordinate information was collected to identify the noise transmission path between the noise source and receiver. The coordinate information is based on the Project site plan showing the plotting of the Project building in relationship to SR-62.

TABLE 6-2: TIME OF DAY VEHICLE SPLITS
Time Period Vehicle Type
Autos Medium Trucks Heavy Trucks
Daytime (7:00 a.m. - 7:00 p.m.) 77.5% 84.8% 86.5%
Evening (7:00 p.m. - 10:00 p.m.) 12.9% 4.9% 2.7%
Nighttime (10:00 p.m. - 7:00 a.m.) 9.6% 10.3% 10.8%
Total: 100.0% 100.0% 100.0%
Source: Typical Southern California vehicle mix.

TABLE 6-3: DISTRIBUTION OF TRAFFIC FLOW BY VEHICLE TYPE (VEHICLE MIX) Roadway
Classification
Total % Traffic Flow1
Total
Autos Medium Trucks Heavy Trucks
SR-62 94.10% 3.72% 2.19% 100.00% 1
Source: Caltrans 2022 Truck Traffic Counts.

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29 7 ON-SITE TRAFFIC NOISE IMPACTS
An on-site exterior noise impact analysis has been completed to determine the traffic-related noise levels and to identify potential necessary abatement measures for the proposed Yonder 29 Palms Project. It is expected that the primary source of noise impacts to the Project site will be traffic-related noise from SR-62.

7.1 ON-SITE EXTERIOR NOISE ANALYSIS
Using the FHWA noise prediction model and the parameters outlined in Tables 6-1 to 6-3, the expected future exterior noise levels for the Project commercial uses were calculated. The onsite traffic noise level impacts indicate that the Project building façade nearest to SR-62 is anticipated to experience an unmitigated exterior noise level of 59.9 dBA CNEL.

The results of the on-site traffic noise analysis indicate that the future exterior traffic noise levels at the commercial use of the Project will satisfy the 65 dBA CNEL exterior noise level standard of the City of Twentynine Palms General Plan Noise Element. Therefore, no exterior noise mitigation measures are required. The on-site transportation noise analysis calculations are provided in Appendix 7.1.

7.2 ON-SITE INTERIOR NOISE ANALYSIS
To ensure that the interior noise levels comply with the City of Twentynine Palms interior noise level standards, future noise levels were calculated at the first and second-floor building facades.

7.2.1 NOISE REDUCTION METHODOLOGY
The interior noise level is the difference between the predicted exterior noise level at the building facade and the noise reduction of the structure. Typical building construction will provide a Noise Reduction (NR) of approximately 12 dBA with "windows open" and a minimum 25 dBA noise reduction with "windows closed." However, sound leaks, cracks and openings within the window assembly can greatly diminish its effectiveness in reducing noise. Several methods are used to improve interior noise reduction, including: (1) weather-stripped solid core exterior doors; (2) upgraded dual glazed windows; (3) mechanical ventilation/air conditioning; and (4) exterior wall/roof assembles free of cut outs or openings.

7.2.2 INTERIOR NOISE LEVEL ASSESSMENT
To provide the necessary interior noise level reduction, a noise level greater than 57 CNEL at a building façade indicate that the Project building will require a windows-closed condition and a means of mechanical ventilation (e.g. air conditioning). Since the nearest building façade would be exposed to noise levels of 59.9 CNEL, the Project is providing air conditioning on all units, offices, and meeting spaces. To satisfy the 45 dBA CNEL interior noise level standard for interior uses, standard windows with minimum STC ratings of 27 for all windows will suffice. The interior noise analysis shows that with mechanical ventilation the Project will satisfy the interior noise level standards.

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31 8 OFF-SITE TRAFFIC NOISE ANALYSIS
The expected Project is anticipated to generate a maximum of 849 external vehicle trip-ends per day with 53 external AM peak vehicle hour trips and 58 external PM peak hour vehicle trips, which would represent an incremental increase to the existing average daily traffic volume on SR-62 of 25,300. While the Project would more than double traffic volumes on Lear Avenue north of Cactus Drive, the increase would not be perceivable due to the dominant traffic noise generated in this area by Twentynine Palms Highway. Therefore, the Project is not expected to generate perceptible noise level increase (i.e., 3 dBA) at nearby sensitive land uses adjacent to study area roadways. Due to the low traffic volumes generated by the Project, the off-site traffic noise levels generated by the Project are considered less than significant and no further analysis is required.

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33 9 SENSITIVE RECEIVER LOCATIONS
To assess the potential for long-term operational and short-term construction noise impacts, the following sensitive receiver locations, as shown on Exhibit 9-A, were identified as representative locations for analysis. Sensitive receivers are generally defined as locations where people reside or where the presence of unwanted sound could otherwise adversely affect the use of the land.

Noise-sensitive land uses are generally considered to include schools, hospitals, single-family dwellings, mobile home parks, churches, libraries, and recreation areas. Moderately noisesensitive land uses typically include multi-family dwellings, hotels, motels, dormitories, outpatient clinics, cemeteries, golf courses, country clubs, athletic/tennis clubs, and equestrian clubs. Land uses that are considered relatively insensitive to noise include business, commercial, and professional developments. Land uses that are typically not affected by noise include:
industrial, manufacturing, utilities, agriculture, undeveloped land, parking lots, warehousing, liquid and solid waste facilities, salvage yards, and transit terminals.

To describe the potential off-site Project noise levels, five receiver locations in the vicinity of the Project site were identified. All distances are measured from the Project site boundary to the outdoor living areas (e.g., private backyards), Project boundary line, or at the building façade, whichever is closer to the Project site. The selection of receiver locations is based on FHWA guidelines and is consistent with additional guidance provided by Caltrans and the FTA, as previously described in Section 5.2. Other sensitive land uses in the Project study area that are located at greater distances than those identified in this noise study will experience lower noise levels than those presented in this report due to the additional attenuation from distance and the shielding of intervening structures. Distance is measured in a straight line from the project boundary to each receiver location.

R1: Location R1 represents existing noise sensitive rural residence located at 69262 Cottonwood Drive, approximately 14 feet to the west of the Project site. A 24-hour noise measurement was taken near this location, L1, to describe the existing ambient noise environment.

R2: Location R2 represents existing noise sensitive rural residence located at 6461 Monte Vista Ave., approximately 152 feet to the northeast of the Project site. A 24-hour noise measurement was taken near this location, L2, to describe the existing ambient noise environment.

R3: Location R3 represents the existing noise sensitive rural residence located at 6202 Twentynine Palms Highway, approximately 418 feet to the west of the Project site. A 24- hour noise measurement was taken near this location, L4, to describe the existing ambient noise environment.

R4: Location R4 rural residence located at 69711 Shoshone Valley Road, approximately 112 feet to the south of the Project site. A 24-hour noise measurement was taken near this location, L3, to describe the existing ambient noise environment.

R5: Location R5 rural residence located at 69721 Shoshone Valley Road, approximately 395 feet to the south of the Project site. A 24-hour noise measurement was taken near this location, L3, to describe the existing ambient noise environment.

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34 EXHIBIT 9-A: SENSITIVE RECEIVER LOCATIONS
LEGEND:
[=] Site Boundary ~ Receiver Locations -• Distance from receiver to Project site boundary (in feet)

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35 10 OPERATIONAL NOISE IMPACTS
This section analyzes the potential stationary-source operational noise impacts at the nearest receiver locations, identified in Section 9, resulting from the operation of the Yonder 29 Palms Project. Exhibit 10-A identifies the representative receiver locations and noise source locations used to assess the hourly average Leq operational noise levels consistent with the City of Twentynine Palms noise standards. Appendix 10.1 includes the detailed calculations for the Project operational noise levels presented in this section.

10.1 OPERATIONAL NOISE SOURCES
This operational noise analysis is intended to describe noise level impacts associated with the expected typical daytime and nighttime activities at the Project site. To present the potential worst-case noise conditions, this analysis assumes the Project would be operational 24 hours per day, seven days per week. The on-site Project-related noise sources are expected to include: the air conditioning units, outdoor activities, music, an outdoor movie screen, trash enclosure activity, and parking lot activity.

10.2 REFERENCE NOISE LEVELS
To estimate the Project operational noise impacts, reference noise levels were taken from manufacturers specifications or measurements were collected from similar types of activities to represent the noise levels expected with the development of the proposed Project. This section provides a detailed description of the reference noise level measurements shown on Table 10-1 used to estimate the Project operational noise impacts. It is important to note that the following projected noise levels assume the worst-case noise environment with the air conditioning units, outdoor activities, music, an outdoor movie screen, trash enclosure activity, and parking lot activity all operating at the same time. These sources of noise activity will likely vary throughout the day.

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36 EXHIBIT 10-A: OPERATIONAL NOISE SOURCE LOCATIONS
LEGEND:
[] Site Boundary □ Air Conditioning Unit • Outdoor Activity Area ♦ Trash Enclosure Activit~ Parking Lot Vehicle Movements ,6. Music * Movie Speakers

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37 TABLE 10-1: REFERENCE NOISE LEVEL MEASUREMENTS
Noise Source
Noise
Source
Height
(Feet)
Min./Hour2 Reference
Noise Level
(dBA Leq)
@ 50 Feet
Sound
Power
Level
(dBA) Day Night 3
Air Conditioning Unit1 3' 45' 30' 43.4 75.0
Outdoor Activity 5' 60' 0' 59.9 91.5
Movies Theater Activity 5' 60' 60' 64.5 96.1
Ambient Music 5' 60' 0' 61.3 92.9
Trash Enclosure Activity1 5' 10' 10' 56.8 88.4
Parking Lot Vehicle Movement 0' 60' 60' 55.5 87.2
1 As collected by Urban Crossroads, Inc.
2 Anticipated duration (minutes within the hour) of noise activity during typical hourly conditions expected at the Project site. "Daytime" = 7:00 a.m. - 10:00 p.m.; "Nighttime" = 10:00 p.m. - 7:00 a.m. 3 Sound power level represents the total amount of acoustical energy (noise level) produced by a sound source independent of distance or surroundings. Sound power levels calculated using the CadnaA noise model at the reference distance to the noise source. Numbers may vary due to size differences between point and area noise sources.

10.2.1 MEASUREMENT PROCEDURES
Some of the reference noise level measurements presented in this section were collected using a Larson Davis LxT Type 1 precisions sound level meter (serial number 01146). The LxT sound level meter was calibrated using a Larson-Davis calibrator, Model CAL 200, was programmed in "slow" mode to record noise levels in "A" weighted form and was located at approximately five feet above the ground elevation for each measurement. The sound level meters and microphones were equipped with a windscreen during all measurements. All noise level measurement equipment satisfies the American National Standards Institute (ANSI) standard specifications for sound level meters ANSI S1.4-2014/IEC 61672-1:2013. (22)

10.2.2 AIR CONDITIONING UNITS
To assess the noise levels created by the air conditioning units, reference noise levels were taken from equipment specifications for a 1- to 3-ton residential ductless mini split outdoor condensing units (Carrier 38MARB). Manufacturers data sheets are included in Appendix 10.1. Each unit was modeled as operating 45 minutes per hour during the daytime and 30 minutes during the nighttime. For this noise analysis, the air conditioning units are expected to be ground mounted adjacent to the proposed buildings. The center of the air conditioning units are anticipated to be located 3 feet above ground level. At a uniform reference distance of 50 feet, each unit would generate a reference noise level of 44.4 dBA (75 dBA Lw).

10.2.3 OUTDOOR ACTIVITY
To assess the noise levels created by the outdoor activities, a reference noise level of 59.9 dBA Leq at 50 feet (91.5 dBA Lw) has been developed to describe dining and drinking activities on outdoor patio areas, with background music playing, people talking, etc. collected by Urban

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38 Crossroads, Inc. are used to describe the outdoor activity expected at the site. The outdoor activity noise levels include kids playing, running, and parents talking and other people in the background on cellular phones. Noise associated with outdoor activities is expected to occur for the entire hour (60 minutes) during daytime hours (7:0 a.m. – 10:00 p.m.).

10.2.4 MOVIE THEATER ACTIVITY
The outdoor movie screen beginning and ending times are dependent on sunset and thus may occur during nighttime hours, i.e., after 10:00 p.m., during the summer months. The audio for the outdoor movie area will be broadcasted by personal radios or similar mobile devices. A reference noise level of 67.8 dBA Leq at 3 feet (75 dBA Lw) for each device is used to model up to 130 individual devices for a combined reference noise level of 64.5 Leq at 50 feet. The movies theater is modeled as operating the full hour during daytime and nighttime activities.

10.2.5 AMBIENT MUSIC
Soft background music will be played in the main and secondary lodge areas throughout the day from 6 AM to 10 PM. Based on the ambient noise level in the Project area the Project site experience daytime ambient noise levels ranging from 48 to 51.3 dBA Leq. Therefore, a reference noise level of 92.9 dBA Lw operating the full hour, which is equivalent to 61.3 dBA Leq at 50 feet, is used to model on-site ambient music. This noise level would be readily noticeable within the lodge areas above ambient noise levels.

10.2.6 TRASH ENCLOSURE ACTIVITY
To describe the noise levels associated with a trash enclosure activity, Urban Crossroads collected a reference noise level measurement at an existing trash enclosure containing two dumpster bins. The trash enclosure noise levels describe metal gates opening and closing, metal scraping against concrete floor sounds, dumpster movement on metal wheels, and trash dropping into the metal dumpster. The reference noise levels describe trash enclosure noise activities when trash is dropped into an empty metal dumpster, as would occur at the Project site. The measured reference noise level at the uniform 50-foot reference distance is 56.8 dBA Leq for the trash enclosure activity. The reference noise level describes the expected noise source activities associated with the trash enclosures for the Project’s proposed building. Typical trash enclosure activities are estimated to occur for 10 minutes per hour.

10.2.7 PARKING LOT VEHICLE MOVEMENTS
Parking activities are based on the number of parking spaces. The Project includes approximately 130 new spaces, which are assumed to have up to 2 movements per hour for a total of 260 events in an hour. Based on studies conducted in Europe and Australia, the average parking procedure, which included movement associated with either entering or exiting the parking area, parking the vehicles, and opening and closing doors resulted in a sound power level of approximately 63 dBA Lw per event (23) (24). Based on the number of parking spaces per lot grouping the total noise level for each parking area is 87.2 dBA Lw.

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39 10.3 CADNAANOISE PREDICTION MODEL
To fully describe the exterior operational noise levels from the Project, Urban Crossroads, Inc. developed a noise prediction model using the CadnaA (Computer Aided Noise Abatement) computer program. CadnaA can analyze multiple types of noise sources using the spatially accurate Project site plan, georeferenced Nearmap aerial imagery, topography, buildings, and barriers in its calculations to predict outdoor noise levels.

Using the ISO 9613-2 protocol, CadnaA will calculate the distance from each noise source to the noise receiver locations, using the ground absorption, distance, and barrier/building attenuation inputs to provide a summary of noise level at each receiver and the partial noise level contributions by noise source. Consistent with the ISO 9613-2 protocol, the CadnaA noise prediction model relies on the reference sound power level (Lw) to describe individual noise sources. While sound pressure levels (e.g. Leq) quantify in decibels the intensity of given sound sources at a reference distance, sound power levels (Lw) are connected to the sound source and are independent of distance. Sound pressure levels vary substantially with distance from the source and diminish because of intervening obstacles and barriers, air absorption, wind, and other factors. Sound power is the acoustical energy emitted by the sound source and is an absolute value that is not affected by the environment.

The operational noise level calculations provided in this noise study account for the distance attenuation provided due to geometric spreading, when sound from a localized stationary source (i.e., a point source) propagates uniformly outward in a spherical pattern. A default ground attenuation factor of 0.5 was used in the noise analysis to account for mixed ground representing a combination of hard and soft surfaces. Appendix 10.2 includes the detailed noise model inputs used to estimate the Project operational noise levels presented in this section.

10.4 PROJECT OPERATIONAL NOISE LEVELS
Using the reference noise levels to represent the proposed Project operations that include air conditioning units, outdoor activities, music, an outdoor movie screen, trash enclosure activity, and parking lot activity, Urban Crossroads, Inc. calculated the operational source noise levels that are expected to be generated at the Project site and the Project-related noise level increases that would be experienced at each of the sensitive receiver locations. Table 10-2 shows the Project daytime operational noise levels at the off-site receiver locations are conservatively expected to range from 33.4 to 38.5 dBA Leq. Table 10-3 shows the Project nighttime operational noise levels at the off-site receiver locations are conservatively expected to range from 25.8 to 32.5 dBA Leq.

Table 10-4 combines and weights the noise levels generated by the Project during the daytime and nighttime and presents the 24-hour CNEL. The noise levels at the off-site receiver locations are conservatively expected to range from 34.0 to 40.1 dBA CNEL.

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40 TABLE 10-2: DAYTIME PROJECT OPERATIONAL NOISE LEVELS Noise Source1 Daytime Noise Level (dBA Leq)
R1 R2 R3 R4 R5
Air Conditioning Unit1 23.0 19.1 18.7 19.8 17.8
Outdoor Activity 35.0 30.7 30.6 32.4 30.4
Movies Theater Activity 32.8 27.8 26.9 28.0 26.2
Ambient Music 32.0 27.0 26.4 29.7 27.6
Trash Enclosure Activity1 20.4 13.4 10.8 12.6 11.7
Parking Lot Vehicle Movement 18.8 11.7 9.0 9.6 8.4
Total (All Noise Sources) 38.5 33.8 33.4 35.3 33.4 1
See Exhibit 9-A for the noise source locations. CadnaA noise model calculations are included in Appendix 10.2.

TABLE 10-3: NIGHTTIME PROJECT OPERATIONAL NOISE LEVELS
Noise Source1 Nighttime Noise Level (dBA Leq)
R1 R2 R3 R4 R5
Air Conditioning Unit1 20.3 16.4 16.0 17.0 15.1
Outdoor Activity 0.0 0.0 0.0 0.0 0.0
Movies Theater Activity 31.8 26.9 26.0 27.0 25.2
Ambient Music 0.0 0.0 0.0 0.0 0.0
Trash Enclosure Activity1 19.4 12.5 9.8 11.7 10.8
Parking Lot Vehicle Movement 17.8 10.7 8.0 8.7 7.4
Total (All Noise Sources) 32.5 27.5 26.6 27.6 25.8 1
See Exhibit 9-A for the noise source locations. CadnaA noise model calculations are included in Appendix 10.2.

TABLE 10-4: DAILY PROJECT OPERATIONAL NOISE LEVELS
Noise Source1 Nighttime Noise Level (dBA CNEL)
R1 R2 R3 R4 R5
Air Conditioning Unit1 27.0 23.1 22.7 23.8 21.8
Outdoor Activity 32.0 27.7 27.6 29.4 27.4
Movies Theater Activity 38.2 33.3 32.4 33.4 31.6
Ambient Music 29.0 24.0 23.4 26.7 24.6
Trash Enclosure Activity1 25.9 18.9 16.2 18.1 17.2
Parking Lot Vehicle Movement 24.2 17.1 14.4 15.1 13.8
Total (All Noise Sources) 40.1 35.2 34.5 35.9 34.0 1
See Exhibit 9-A for the noise source locations. CadnaA noise model calculations are included in Appendix 10.2.

10.5 PROJECT OPERATIONAL NOISE LEVEL COMPLIANCE
To demonstrate compliance with local noise regulations, the Project-only operational noise levels are evaluated against exterior noise level thresholds based on the City of Twentynine Palms

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41 exterior noise level standards at nearest noise-sensitive receiver locations. Table 10-5 shows the operational noise levels associated with the Project will satisfy the City of Twentynine Palms exterior noise level standards at all nearby receiver locations. Therefore, the operational noise impacts are considered less than significant at the nearest noise-sensitive receiver locations.

TABLE 10-5: OPERATIONAL NOISE LEVEL COMPLIANCE
Receiver
Location1
Project Operational
Noise Levels
(dBA Leq)
2 Exterior Noise
Level Standards
(dBA Leq)
3 Noise Level
Standards
Exceeded?4
Daytime Nighttime Daytime Nighttime Daytime Nighttime
R1 35.3 20.3 55 45 No No
R2 31.0 16.5 55 45 No No
R3 30.9 16.1 55 45 No No
R4 32.6 17.1 55 45 No No
R5 30.6 15.2 55 45 No No 1
See Exhibit 9-A for the receiver locations.
2 Proposed Project operational noise levels as shown in Tables 10-2 and 10-3. 3 Exterior noise level standards are shown in Table 3-1. 4 Do the estimated Project operational noise source activities exceed the noise level standards? "Daytime" = 7:01 a.m. to 10:00 p.m.; "Nighttime" = 10:01 p.m. to 7:00 a.m.

10.6 PROJECT OPERATIONAL NOISE LEVEL INCREASES
To describe the Project operational noise level increases, the Project operational noise levels are combined with the existing ambient noise levels measurements for the nearest receiver locations potentially impacted by Project operational noise sources. Since the units used to measure noise, decibels (dB), are logarithmic units, the Project-operational and existing ambient noise levels cannot be combined using standard arithmetic equations. (2) Instead, they must be logarithmically added using the following base equation:

SPLTotal = 10log10[10SPL1/10 + 10SPL2/10 + … 10SPLn/10] Where “SPL1,” “SPL2,” etc. are equal to the sound pressure levels being combined, or in this case, the Project-operational and existing ambient noise levels. The difference between the combined Project and ambient noise levels describes the Project noise level increases to the existing ambient noise environment. As indicated on Table 10-6, the Project will generate daytime operational noise level increases ranging up to 0.2 dBA Leq at the nearest receiver locations.

Similarly as indicated on Table 10-7, the Project will generate nighttime operational noise level increases ranging up to 0.2 dBA Leq at the nearest receiver locations. Project-related operational noise level increases will satisfy the operational noise level increase significance criteria presented on Table 4-1. Therefore, the incremental Project operational noise level increase is considered less than significant at all receiver locations.