Hi-Desert Water District

U.S. BUREAU OF RECLAMATION

Tom Dodson & Associates

JUNE 2009

(Omitted, with no comment)

(Omitted, with no comment)

The proposed project has five general objectives:

1. Construct a wastewater collection system to reduce the quantity of leachate from septic tank systems flowing into the Warren Valley Groundwater Basin (Basin) used for the District’s potable

water supply.

2. Treat wastewater to a level such that percolated effluent will not degrade groundwater quality. The enhancement of groundwater quality is proposed to be achieved by reducing the amount of nitrate rich leachate from septic tanks in the area percolating into the Basin groundwater aquifer.

3. (Omitted, with no comment)

4. Maximize the total water supply available to the District.

5. Minimize any adverse economic and environmental impacts to the community.

In addition to these general objectives, specific objectives for the Phase 1 treatment facilities are as

follows:

1. (Omitted, with no comment)

2. (Omitted, with no comment)

The installation of this wastewater system infrastructure is considered essential to the District in

order to continue meeting the public health and safety requirements for water supply within its

service area and to meet the water quality objectives of the Colorado River Basin Regional Water

Quality Control Board (Regional Board or RWQCB).

(Note: some parts of this have been deleted because there was no comment needed or germaine to

the elements discussed in this section/subsection)

As previously described this project consists of the construction and installation of the following

components. The District intends to initially sewer the central portion of the Town of Yucca Valley to

convey an annual average flow of 2 MGD of wastewater to the WRF currently discharged to septic

tanks. This initial project is referred to as Phase 1. In the future, if the Phase 1 facilities do not

adequately protect groundwater quality, or if the RWQCB requires more areas to be sewered, or if

additional capacity is needed, the collection, treatment and disposal facilities will be expanded to

collect an additional 1 MGD of sewage. The additional facilities are referred to as Phase 2 facilities.

Phase 3 facilities will be designed to collect an additional 1 MGD of wastewater flow for a total

system capacity of 4 MGD. Ultimate build-out in the District’s Yucca Valley service area could be as

high as 6 MGD, but due to the area’s slow rate of growth, this is not forecast to occur until the

distant future. If a wastewater collection system is required in the Yucca Mesa-portion of the

District’s service area in the future, the assumption has been made that a separate treatment

facility will be located within the Yucca Mesa area. The wastewater will be treated to meet Title 22

recycled water standards/requirements and will be delivered to recharge basins operated by the

District to percolate into the Warren Valley Groundwater Basin (Basin).

The proposed project is located within the Town of Yucca Valley in the County of San Bernardino.

The proposed interim wastewater treatment plant facilities will be located approximately 1,000 feet

south of State Route 62 (SR 62) (Twentynine Palms Highway), east of Indio Avenue, north of

Sunnyslope Drive, and west of La Contenta Road (see Figure 2-1).

Yucca Valley, San Bernardino County is located in the Morongo Basin portion of the Mojave Desert,

approximately 70 miles east of the City of San Bernardino (refer to Figure 1-1). Access to the region

is by SR 62 which extends west to Interstate 10 and east to the Colorado River and the Arizona

state line from Yucca Valley. The proposed trunk sewer pipeline alignments and wastewater

treatment plant facilities generally occur in alluvial deposits derived from the Little San Bernardino

Mountains to the south. The alluvial fan slopes to the north at a 1-2 percent gradient at a general

elevation of approximately 3,300 feet above sea level. (*!)The Pinto Mountain fault (considered

active) is located about one-quarter mile north of the proposed treatment plant site. No other

geologic hazards are known to occur in the project area. (*2)The only topographic feature within

the project site is an ephemeral desert wash area, vegetated with Joshua tree-creosote scrub,

intermixed with Mormon tea. All water supplies are extracted from the local Warren Valley

Groundwater Basin by Hi-Desert Water District, with supplemental water consisting of State Water

Project (SWP) water imported from the State Aqueduct in Hesperia by agreement with the Mojave

Water Agency (MWA). Water quality issues are managed by the Colorado River Basin Regional

Water Quality Control Board (Regional Board). Project area land uses consist of a mix of open

space, residential, commercial, and limited industrial uses. (*3)A Joshua tree-creosote bush scrub

plant community occurs in the general area, and desert tortoise are also known to inhabit the

general area. At the present time the plant site is open desert with typical human disturbance from

being located near existing residences. The climate in the project area is that of a subtropical

upland desert with annual precipitation less than 10 inches, averaging 6.44 inches. Temperatures

can vary from 0°F in winter to above 110°F in the summer. Mean summer temperature is 88°F and

in winter is 49°F. Air quality in the region is good, but during the summer transported pollutants

from the South Coast Air Basin (SoCAB) can cause ozone concentrations to violate federal and state

standards on rare occasions. The project area is located within the Mojave Desert Air Basin (MDAB

or Basin) and the Mojave Desert Air Quality Management District (MDAQMD) manages air quality for

this Basin. Access to the project site can be obtained from the main area roadway, SR 62

(Twentynine Palms Highway), which traverses east-west through the Town of Yucca Valley to the

north of the treatment plant site. The north-south cross streets are Indio Avenue on the west and

La Contenta Road on the east of the proposed WRF site. The project site can be accessed from La

Contenta off of SR 62, then west on Sunnyslope to the project site.

The proposed project is the construction and installation of a wastewater reclamation facility (Hi

Desert WRF) with an initial treatment capacity of 2 MGD and an build-out treatment capacity of 6

MGD. Phased development of the Hi Desert WRF envisions the initial facility size as capable of

processing up to 2 MGD of wastewater; a second phase, Phase 2, would expand the WRF to 3 MGD;

Phase 3 envisions a treatment capacity of 4 MGD; and the build-out WRF would have a treatment

capacity of up to 6 MGD.

The Phase 1 sewer collection system will focus on the urban development in close proximity to State

Highway 62 (Twentynine Palms Highway). The Phase 2 collection system would expand to the

majority of urban development within the existing District service area. Phase 3 would connect

much of the remaining existing residential and commercial development within the Town of Yucca

Valley to the WRF.

Infill development within the Town of Yucca Valley is forecast to create an ultimate demand for 6

MGD of treatment capacity. If approved by the community, the 2 MGD capacity WRF would be

installed in the near future, perhaps coming on line in 2012. Implementation of future phases would

be dependent upon the pace of connections dictated by the Regional Board and actual future

growth.

Omitted with no comments

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The No-Action alternative will result in wastewater treatment facilities not being installed as outlined

….

The No-Action alternative does not contribute to the protection and enhancement of the

District’s water quality as envisioned in both the Regional Water Management Plan (Mojave Water

Agency 2004) and the District’s Strategic Plan (2008). Nitrate contamination in the area would still

be produced and percolate into the local groundwater aquifer in conflict with the Regional Board’s

Basin Plan (2005).

The No-Action alternative would result in the fewest direct natural environmental effects of available

alternatives, because no physical changes to the environment within the area of potential impact

would result from construction activities. However, the result of emplementing this alternative is the

continued degradation of groundwater quality due to nitrates in the Warren Valley Groundwater

Basin and possibly in downstream aquifers. Therefore, this alternative is not considered a feasible or

reasonable alternative for consideration by the District.

The MWH PDR included a discussion of an alternative of installing individual treatment systems.

The text of this discussion, presented above, is repeated here for information. Nitrate removal from

wastewater requires some form of treatment and some form of managing the nitrate after it is

separated from wastewater or chemically modified during treatment. Most of the existing

residences and businesses currently manage their domestic wastewater with underground septic

tank and leach systems or seepage pits. It is from these individual systems that the nitrate is

entering the local groundwater aquifer. There are individual advanced underground wastewater

treatment systems that can be installed, but the effectiveness of such systems in removal of

sufficient nitrate and the process of imposing such systems is beyond the scope of this analysis. The

summary of treatment technologies screened in the PDR are provided in Table 2-2 (Table 3-1 of the

PDR). Tables 3-2 through 3-6 of the PDR (Appendix 1) contain a fatal flaw analysis of the systemwide

treatment alternatives and of specific technologies.

The MWH PDR contained the following conclusion for options related to onsite treatment

(Some parts of this sub-section have been omitted because they were not needed to address this

element)

… Only sites that are not directly upstream of domestic water wells and that have sufficient depth of

vadose zone (the area between the ground surface and the groundwater table) were deemed

adequate for siting the WRF. Due to the shallow vadose zone to the west, south and north portions

of the Warren Valley Basin, a site in the east-central portion of the Basin was deemed essential.

water table within which the moisture content is less than saturation (except in the capillary

fringe) and pressure is less than atmospheric. Soil pore space also typically contains air or

other gases. The capillary fringe is included in the vadose zone.

(re. http://www.teachmefinance.com/Scientific_Terms/Vadose_Zone.html

Therefore, based on the large acreage of undeveloped area, depth of vadose zone, and lack of wells

immediately downstream, the project site or another site in the immediate vicinity was determined

to be the only location in the Basin available to support the proposed WRF. Since the environmental

variables at the selected site represent those of the surrounding area, the project location was

judged to be representative of the available sites in the Basin. Thus, this alternative will not be

given further consideration.

Alternative Treatment Systems

Although the treatment system options would be installed at the same proposed WRF site, there are

minor variations in the amount of area and amount of energy required for each system. The

following comparative evaluation of the treatment system alternatives is abstracted from the PDR.

Minor editing has been included for clarity.

Matrix Comparison of Treatment Alternatives

Each of the four alternatives were compared against each other using weighted criteria. This

method involves three steps:

1. Establish a set of criteria and assign a weight to each criteria based on level of importance to the

District. The total of the criteria weights should be equal to 100%.

2. Score each of the alternatives on a scale of 1 – 10 for each criteria.

3. Multiple each score by the corresponding weights; those produce are then added together to give

a total weighted score for each alternative.

The list of criteria for the matrix evaluation of the treatment alternatives are listed in Table 2-9

along with the criteria weighting.

Low Initial Capital Cost 15%

Low O&M Cost 35%

Small Footprint 5%

High Treatment Reliability 15%

Simple O&M 10%

Flexibility for Future 20%

The results of a weighted matrix evaluation of the four alternatives are shown on Table 2-10.

Alternative 1 – Extended Aeration 6.85 98%

Alternative 2A – High Rate MBR 5.90 84%

Alternative 2B – Extended Aeration MBR 7.00 100%

Alternative 3 – Conventional Activated Sludge 5.35 76%

Risk Assessment of Treatment Alternatives

The comparison described above is based on the expected performance requirements, site

conditions, and other assumed factors. In reality, the project faces a number of risks that are not

directly addressed in the comparison. Table 2-11 lists a number of risks, and which alternatives

would be less than impacted by them.

1. Geotechnical Low Medium 2A- High Rate MBR

2B- Ex Aeration MBR

2. Material Cost Increases Medium Low 2A- High Rate MBR

2B- Ex Aeration MBR

3. Low Perc Rate/High Dilution Req Low High None

4. Energy Availability Medium Medium 1- Extended Aeration

5. Vendor Reliability Low High 1- Extended Aeration

6. Emerging Contaminants Medium High 1- Extended Aeration

2B- Ex Aeration MBR

7. Future Treatment Requirements Medium High 2A- High Rate MBR

2B- Ex Aeration MBR

1. Geotechnical Risks – A geotechnical investigation will need to be completed prior to the

construction of a treatment plant. These unknown condition may influent the placement of

the treatment facility on the site. Facilities with a large footprint have a higher risk that

unfavorable geotechnical conditions will impact either the cost of the facilities or even the

ability to built the facilities all together. The high rate and extended aeration MBR alternatives are

the preferred alternative when it comes to the risk associated with geotechnical issues due to the

small footprint of these treatment trains.

2. Material Cost Increases – Facilities with big structures require large quantities of concrete and

rebar for construction. The last decade has shown large relative increases in the cost of both

concrete and steel. Such increases could increase the final bid cost for the project. Therefore,

treatment trains with a small footprint and lower concrete requirement will reduce the risk

associated with material cost increases. These treatment trains would be the high rate and

extended aeration MBR alternatives.

3. Low Percolation Rate/High Dilution Required – One of the treatment processes is the percolation

ponds used to recharge the groundwater basin. The percolation rate of the soils in the area is

currently unknown as well as the amount of dilution water that would be required by the RWQCB.

These two factors govern the size of the recharge basins which may require more land than

previously thought. All treatment processes are subject to the risk of low percolation rates or a high

dilution requirements.

4. Energy Availability – Technologies with greater energy demand have an increased sensitivity to

increases in energy costs. The extended aeration alternative is least subject to this risk, due to the

low energy requirements in comparison with the other alternatives.

5. Vendor Reliability – Technologies with proprietary equipment are susceptible to difficulties with

the vendor which can have a direct impact on the project schedule and success. The extended

aeration alternative is least subject to this risk, since this is a conventional technology without a lot

of proprietary equipment.

6. Emerging Contaminants – Emerging contaminants including NDMA, personal care products and

pharmaceuticals (PCPP) and disinfection by-products, while not currently regulated by RWQCB,

could become regulated. Treatment processes with longer sludge ages provide a better level of

treatment of PCPP. The extended aeration and extended aeration MBR alternatives are the

preferred alternatives when it comes to the risk associated with emerging contaminants due to the

longer sludge age.

7. Future Treatment Requirements – Future regulations may require treatment of wastewater

effluent using reverse osmosis (RO) before recharging groundwater. If such a system is required it

will need to be preceded by micro-filtration. MBRs use micro-filtration, so MBR effluent could go

directly to RO without future treatment. The high rate and extended aeration MBR alternatives are

the preferred alternatives when it comes to the risk associated with future treatment requirements.

All of these treatment systems can meet the water quality objectives for the Hi-Desert WRF. Also,

they all require approximately the same amount of area and the degree of disturbance associated

with the other three alternative treatment systems. Based on the comparative evaluation in the

discussion above, the overall effects of the alternative systems are considered to be comparable.

Thus, none of the alternative treatment systems will be given further consideration in this

document.

Alternative Sewer Collection System Design

The Sewer Collection System Master Plan is provided in Appendix 2 of this document and

summarized in the project description above. The Master Plan assigns the collection system

pipelines to disturbed areas for over 95% of the 407,800 lineal feet of the system required to serve

the District’s proposed wastewater collection service area. Further, a review of all of the pipeline

alignments in the field indicates that no substantial biological or cultural resource occur within the

proposed alignments. Any other alternative system would, of necessity, have to be located outside

of existing disturbed rights-of-way. Therefore, no alternative pipeline alignments are will be given

further consideration in this document.

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Monitoring of air quality in the San Bernardino County portion of the MDAB is the responsibility of

the MDAQMD headquartered in Victorville. Because of the low population density within the

MDAQMD, limited monitoring resources are distributed over a relatively large geographic area. The

heaviest concentration of measurement is in the area of greatest development, the Mojave River

corridor. Air quality monitoring for ozone, the primary ingredient in regional photochemical smog,

nitrogen oxides, sulfur oxides, carbon monoxide, and respirable particulate matter (PM10) is

conducted at the Twentynine Palms monitoring station, which is closest station to the Yucca Valley

project area. Data for 2000-2002 for some parameters are shown on Table 3-2. No violations of the

federal one-hour ozone standard occurred at this station in this period, but days exceeding the

federal eight-hour standard were 4-13. The number of days exceeding the state standard for ozone

ranged from 3-16. No violations of federal standards for PM10 occurred in this period, but the State

PM10 standard of 50 ug/m3 was exceeded on 1-16 days.

As summarized above, ozone and particulates are seen to be occasional air quality concerns in the

Yucca Valley area. Exceedances of the more stringent state standard for Ozone and PM10 have

occurred periodically in the area. Although the magnitude of violations of ozone standards is much

less severe than in the SoCAB, the combination of the downwind location of Yucca Valley, and the

continued growth of upwind communities in Riverside and San Bernardino Counties as a pollution

source area for the project area, suggests that currently observed violations will continue until the

SoCAB meets ambient air quality standards. Violations of particulate standards in the project area

have been linked more to localized soil disturbance and windstorms than the organic particulate

matter from vehicle exhaust found in the more heavily populated areas of southern California.

Violations of particulate standards due to inorganic soil materials are thought to be less unhealthful

than those generated by combustion sources such as industry and motor vehicles. Clean air

attainment planning requirements, however, do not distinguish between organic and inorganic

pollutants. Because of the occasionally high levels of respirable particulate matter (PM10)

associated with strong wind events, substantial portions of the MDAB are designated as a federal

non-attainment airshed for PM10. While "imported" pollutants such as ozone and, to some extent,

particulate matter do on occasion exceed standards, locally generated pollutants such as carbon

monoxide (CO) or nitrogen oxides (NOx) are low within the Yucca Valley area because background

levels never exceed allowable levels and the sources of such emissions within the project area are

limited. The Mojave Desert area experiences very low baseline levels of primary (other than

photochemically reacted) automobile pollution such that the local airshed appears capable of

accommodating identified future growth with very nominal localized air quality concerns. Although

the dispersive capacity of the atmosphere in the desert is limited when cool air pools near the

surface at night during the cooler months, a much larger level of development, such as occurs in

Las Vegas or Phoenix (one plus million people), is needed to create violations of CO or NOx

standards. Comparison of the size of forecast population growth (population of 19,200 people in

Yucca Valley in 2000, with a conservatively high 3% annual growth rate, would increase to 25,804

by 2010) with the scope of development needed to create a significant air quality impact indicates

that this growth is not forecast to generate significant impacts from CO or NOx.

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The project area encompasses the sewer collection system and the Hi-Desert water reclamation

facility (WRF) site. There are no perennial or permanent water bodies, lakes or streams, within the

project area. There are several ephemeral or intermittent stream channels within the project area.

None of these eight-to-ten ephemeral channels in the project area are formally named on the

United States Geological Survey (USGS) Topographic maps of the project area.

The streams originate in the Little San Bernardino Mountains to the south and in the Sawtooth

Mountain ridge that bounds the project area to the north. The largest stream is locally referred to as

“Yucca Wash.” During major precipitation events it collects flows from the tributary “blue line”

stream channels shown on these USGS Topographic Maps (Yucca Valley North and South, and

Joshua Tree North and South, 7.5' Topographic Maps).

For most of the WRF site and most of the remaining project area, surface runoff occurs as sheet

flow that ultimately enters the alignment of the ephemeral channels. Note the term “blue line”

refers to a stream channel with a defined bed and bank as it is shown on a USGS Topographic Map.

Refer to Figure 2-1.

The proposed WRF site contains one surface water feature, a blueline, ephemeral desert wash,

which traverses the western portion of the site. This ephemeral stream originates in the Little San

Bernardino Mountains to the south. The wash flows southwest to northeast across the property and

exits the property where it flows beneath SR 62. From there, this dry desert wash extends to the

northeast until it has a confluence with Yucca Creek Wash and continues to flow east into the

Community of Joshua Tree.

From there Yucca Creek Wash then flows north to dry lakes, which are considered isolated waters of

the United States. The wash receives flows primarily from the upland areas south of the site that

extend to the front of the north facing slopes of the Little San Bernardino Mountains. According to

the biological assessment conducted by Frank Hovore & Associates in July 2004, the wash is

sparsely vegetated by Joshua tree-creosote scrub in the upland areas, desert willow within the wash

bottom, annual wildflower species in the open terraces along the bottom margins, and Mormon tea,

which dominates the overall drainage. For the remainder of the project area, the future sewer lines

will occasionally cross an ephemeral stream channel along its alignment. In most cases these

crossing will occur within existing paved and graded road rights-of-way. Based on the field survey of

the sewer line alignment, no wetlands or riparian habitats are located within the proposed project

area or along the pipeline alignments. Because these stream channels are isolated and ephemeral,

the preliminary finding is that they are not subject to U.S. Army Corps of Engineers (Corps) Clean

Water Act Section 404 jurisdiction, i.e., they are not waters of the United States. On the other hand

the channels appear to be waters of the State of California and are within the jurisdiction of the

California Department of Fish and Game (CDFG). A CDFG 1602 Streambed Alteration Agreement will

need to be obtained for any disturbances of the ephemeral stream channels within the project area.

Finally, it is also probable that the California Regional Water Quality Control Board, Colorado River

Basin (Regional Board) will assert jurisdiction under its Porter-Cologne responsibilities and require

waste discharge requirements for these disturbances.

According to the Town of Yucca Valley General Plan (1995) Exhibit V-3, the WRF project site is

located within a Zone A flood hazard area, which designates areas of 100-year flooding. As

presently envisioned, the WRF will be located to the east of the 100-year flow line, but based on

final engineering the WRF facilities may encroach within this area.

The water supplied to Yucca Valley is extracted from the Warren Valley Groundwater Basin and the

Ames Basin. The District is the principal water purveyor servicing the Yucca Valley area. The District

obtains all of its water supplies from 13 active wells that pump groundwater from the Warren Valley

Groundwater Basin. Fifteen of these wells are generally located along the Yucca Wash or Creek, with

two located on the Mesa to the north. Current estimated production is approximately 3,000 acrefeet

per year (acre-ft/yr). According to the District, it also has rights for up to 800 acreft/ yr from

the adjacent Ames Valley Basin. The District also receives imported water from the Mojave Water

Agency (MWA) and the State Water Project (SWP) to supplement local groundwater supplies. This

water is piped to the project area and recharged into the Warren Valley Basin through a series of

recharge basins in Town of Yucca Valley along Yucca Creek Wash.

According to a U.S. Geological Survey study, published in 1972 (USGS 1972), the Warren Valley

Groundwater Basin was reported to be small and not exceeding 200 acre-ft/yr of natural recharge.

Groundwater pumped from wells in the 1950s and 1960s was used chiefly for domestic uses. The

groundwater in storage in 1958 was computed to be 106,000 acre-ft. It was surmised that the

consumptive-use in the basin since 1958, i.e., until 1972, still yielded at least 96,000 acre-ft of

groundwater in storage. Since the late-1990s the District has been importing and recharging

groundwater in recharge basins constructed for this purpose. The imported water has been used to

offset and eliminate any continued cumulative contribution to overdraft of District operations.

According to the Regional Board’s Water Quality Control Plan (page 2-3), the groundwater resources

in the Warren Valley Groundwater Basin are considered suitable for municipal or domestic water

supply. The Warren Valley Groundwater Basin is part of the Joshua Tree Hydrologic Unit (708.00

Area Code) and is designated as the Warren “Hydrologic Area” (HA) (708.20 Area Code) on the

Colorado River Hydrologic Basin Planning Area Map. Table 2-5 identifies the beneficial uses of

groundwaters in this Basin to support municipal (MUN) and industrial (IND) beneficial uses.

Regarding water quality, the Warren Valley Groundwater Basin was considered to be historically low

in dissolved solids. Concentrations ranged from approximately 120 to 250 mg/L, and averaged

about 160 mg/l, according to data from a 1972 study (USGS 1972). Fluoride concentrations in that

time period ranged from 0.2 to 1.0 mg/L, and averaged 0.4 mg/L. No concentrations of ions in

excess of the limits recommended by the U.S. Public Health Service at that time were reported. A

more recent study (USGS 2002) focused on lithologic and water quality data for the years 1992-

1998. Two monitoring stations were developed in the Warren Groundwater Basin, YV-1 and YV-2.

Dissolved solids for station YV-1, depths of 230-570 feet below-ground surface, ranged from 158-

502 mg/L. Dissolved solids for station YV-2, depths of 300-570 feet below-ground surface, ranged

from 179-309 mg/L. Dissolved nitrogen (NO2 and NO3) levels, expressed as mg/L of N, ranged

from 2-30.3 mg/L for station YV-1 and from 1.09-11.2 mg/L for station YV-2. Concentrations of

nitrate above 10 mg/L are considered unhealthy for routine human consumption, and small babies

may be at risk with even lower concentrations.

February 2009 sample from 1N/6E-28NP1S (the Mental Physics well).

This nitrate plus nitrite concentration was analyzed to be 18.4 mg/L as N; The EPA MCL for nitrate is

10 mg/L. The pharmaceutical results were available only for Well 32G1 (WRF onsite piezometer)

because insufficient volume of water was available from well 28N1. As shown in Table 3-4, none of

the pharmaceuticals analyzed exceeded detection levels.

According to the Town of Yucca Valley General Plan Water Resources Element, there are several

sources for groundwater contamination within the area, including septic tank systems, underground

oil and gas storage tanks, and a District well, which has already been capped and filled.

The Water Quality Control Plan, or “Basin Plan,” for the Colorado River Basin Region (California

RWQCB 1994) describes the beneficial uses and water quality objectives for both surface and

groundwaters within its jurisdiction. As noted above, the proposed project is generally located in the

Morongo Basin, more specifically in the Joshua Tree Hydrologic Unit (HU) and the Warren [Basin].

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Onsite subsurface septic tank-leach systems are used throughout the Yucca Valley area, for

residential, commercial and industrial operations. There is no regional wastewater treatment facility.

However, due to the effects of these individual systems on nitrates and total dissolved solids levels

in groundwater resources, the District constructed a Nitrate Removal and Blending Plant, which

treats multiple groundwater wells. Operations began in 2002. Some larger commercial or residential

developments may utilize package wastewater treatment systems.

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(Note that parts of this were omitted, to focus on the element effected by the comment given.)

The proposed project is located within the Town of Yucca Valley in San Bernardino County. The

project area is subject to regional and local planning guidance and regulations. The only federal and

state land use policies or regulations that would potentially affect the project are those for specific

resources (such as for mineral and biological resources).

Otherwise, the project area is subject to county-wide and regional planning efforts in regional

growth management and environmental management, particularly for congestion management

(transportation) and solid waste management issues. The project area is also subject to regional

planning efforts, in which regional comprehensive plans for growth management,

mobility/transportation, and air quality management apply. The governing land use documents are

the San Bernardino County General Plan and the Town of Yucca Valley General Plan and associated

Zoning Ordinances and Development Codes. Applicable plans will be described in the following

section, in the context of consistency of the proposed project with these plans.

Consistency with State, Regional and Local Plans

There are currently no adopted Habitat Conservation Plans, Natural Community Conservation Plans,

or other approved local, regional, state habitat conservation plans associated with the proposed

project area. Therefore, no potential exists for conflicts with any such plans from implementing the

proposed project. There are no designated Wild and Scenic Rivers in the project area. The area is

not within a Coastal Zone Management Area.

Therefore, the federal and state plans associated with such designated areas do not apply to the

proposed project.

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This section of the document discusses ecological system and natural community issues of concern.

The focus of this section is on biological communities, not individual plants or animal species. This

section also includes information on wildlife corridors and habitat fragmentation. Wildlife corridors

are areas of habitat used by wildlife for seasonal or daily migration. Habitat fragmentation involves

the potential for dividing sensitive habitat (unique natural communities or natural communities of

concern) and thereby lessening its biological value. Habitat areas that have been designated as

critical habitat under the Federal Endangered Species Act are discussed in a following section which

addresses threatened and endangered species, and wetlands and other waters of the United States

and State of California are also discussed in a following section of this document. Wetlands and

other waters are protected under a number of laws and regulations. At the federal level, the Clean

Water Act (33 U.S.C. 1344) is the primary law regulating wetlands and waters. The Clean Water Act

(CAA) regulates the discharge of dredged or fill material into waters of United States, including

wetlands. Water of the United States include navigable waters, interstate waters, territorial seas

and other waters that may be used in interstate or foreign commerce. To classify wetlands for the

purposes of the CAA, a three-parameter approach is used that includes the presence of hydrophytic

(water-loving) vegetation, wetland hydrology, and hydric soils (soils subject to

saturation/inundation). All three parameters must be present, under normal circumstances, for an

area to be designated as a jurisdictional wetland under the CAA. Section 404 of the CAA establishes

a regulatory program that provides that no discharge of dredged or fill material can be permitted if

a practicable alternative exists that is less damaging to the aquatic environment or if the nation=s

waters would be significantly degraded. The Section 404 permit program is run by the U.S. Army

Corps of Engineers (Corps) with participation and some oversight by the federal Environmental

Protection Agency (EPA).

The Executive Order for the Protection of Wetlands (EO 11990) also regulates the activities of

federal agencies with regard to wetlands. Essentially, this EO states that a federal agency, such as

the FRA, cannot undertake or provide assistance for new construction located in wetlands unless the

head of the agency finds: (1) that there is no practicable alternative to construction and (2) the

proposed project includes all practicable measures to minimize harm. At the state level, wetlands

and waters are regulated primarily by the California Department of Fish and Game (CDFG) and the

Colorado River Regional Water Quality Control Board (Regional Board or RWQCB). Sections 1600-

1607 of the Fish and Game Code require any agency that proposes a project that will substantially

divert or obstruct the natural flow of or substantially change the bed or bank of a river, stream, or

lake to notify CDFG before beginning construction. If CDFG determines that the project may

substantially and adversely affect fish or wildlife resources, a Lake or Streambed Alteration

Agreement will be required. CDFG jurisdictional limits are usually defined by the tops of the stream

or lake banks, or the outer edge of riparian vegetation, whichever is wider. The Regional Boards

were established under the Porter-Cologne Water Quality Control Act to oversee water quality. This

is done through the issuance of water quality certifications in compliance with Section 401 of the

Clean Water Act when the area of potential effect is located in waters of the United States. When

only State waters are involved in the discharge of dredged or fill material, the Regional Board can

review and issue waste discharge requirements (WDR) under the Porter-Cologne Act to achieve the

same water quality protection objectives.

As part of the work for the General Plan, the Town of Yucca Valley and surrounding areas were

categorized and mapped for Biological Resources Values (Tierra Madre Consultants, 1994). The

proposed WRF project site is considered to be in a High Biological Resource Value area, due to the

fact that it is an undeveloped area vegetated by native scrub and woodland habitat. A blueline,

from the southeast corner of the property and receives flows from the Little San Bernardino

Mountains and alluvial upland areas to the south. The WRF site remains undeveloped at this time.

According to the General Plan (1995), surveys of vacant lands must be completed and project

proposals are reviewed and evaluated to assure minimal impacts to existing habitat and wildlife.

Most of the sewer collection system will be placed in existing paved or graded roadway alignments.

All of the sewer alignments shown on Figure 2-2 were surveyed by biologists and support staff of

Tom Dodson & Associates. Biology surveys of both the 80-acre proposed WRF site and the sewer

pipeline alignments are provided as Appendix 4 to this IS/EA. The following characterizes the

general plant community (ies) and wildlife habitat that occurs within the proposed WRF and sewer

pipeline project areas.

Flora

The project’s general area of potential impact is located within the predominant plant communities

of the Town, Joshua Tree Woodland and Creosote Bush Scrub. The Joshua Tree Woodland is a state

designated Community of Highest Inventory Priority. According to the Biological Assessment

completed for the General Plan (Tierra Madre Consultants ,1994) the Joshua Tree Woodland

species, and with numerous shrub species between 3-13 feet tall. These shrubs include: the Mojave

perennial grasses, and introduced plants from local landscaping activities. The Creosote Bush Scrub

community also occurs in the general area of the project and is similar to the Joshua Tree

Woodland, but it is dominated by the creosote bush with scattered Joshua Trees. It

is sometimes difficult to distinguish the two.

The Town of Yucca Valley requires developers to salvage native joshua trees and shrubs for

incorporation in project landscaping or to transplant trees to other sites. The Town has a Joshua

Tree Removal permit process. The District would be subject to these requirements. Additionally, San

Bernardino County Ordinance 3175 recommends that all creosote bush rings greater than 10 ft. in

diameter be preserved. Native plants such as cactus are to be salvaged. The proposed WRF site

contains several Joshua Trees, creosote bush, Mojave yucca, cheesebush, annual plant species, and

cacti. A site-specific biological assessment was conducted for this area and is provided as Appendix

4 to this document. The proposed pipeline routes are located primarily along previously disturbed

road rights-of-way. However, in certain areas both the sewer pipelines and pump stations cross

undisturbed areas, including ephemeral stream channels which are described in the surface water

hydrology discussions above (Section 3.2). A site-specific biological assessment was conducted for

the sewer line alignments and is provided as Appendix 4 to this document.

The biological assessments indicated that the plant community at the proposed WRF site is Creosote

Creosote Bush Scrub intermixed with Mormon tea. The wash bottom is inhabited by desert willow

which shows all plants identified at the wastewater treatment plant site. The same general list of

plant species were found along the pipeline alignments where these alignments crossed undisturbed

or disturbed natural communities. Refer to the species list in Appendix 4.

Fauna

Several sensitive and one listed (i.e., threatened or endangered) animal species occur within the

Town, as associated with the above plant communities. Those species included in the biological

survey for the General Plan (Tierra Madre Consultants, 1994) included: 42 species of reptiles –

desert spiny and fence lizards, snakes (gopher snake and several types of rattlesnake), and the

threatened desert tortoise and sensitive San Diego horned lizard; 235 species of birds – the

sensitive burrowing owl, loggerhead shrike and LeConte’s thrasher, as well as numerous raptor and

songbird species; 59 mammal species–several types of bats, desert cottontail, jackrabbit, ground

squirrels, kangaroo rats, coyote, raccoon, bobcat, mountain lion, and mule deer. A focused Desert

Tortoise Survey (following the survey protocol established by the USFWS) was conducted by Frank

Hovore & Associates in 2004 as part of the biological survey. No tortoises and no recent or

historical signs of tortoises (burrows, scat, carapaces) were observed on the project site or in its

state Species of Special Concern. Due to the use by off-road vehicles throughout the Town and

project area, these species are not expected to be present on the project site. In addition, there was

encountered in the project area, as well as nesting behavior observed in other bird species. The

State of California prohibits the take of active bird nests (California Fish and Game Code Sections

3503 and 3503.5). Other bird species observed within the project area (both sewer line alignments

Wildlife on the WRF site included species observed directly or by indicative sign (scat, tracks,

As a result of the desert tortoise protocol surveys of the WRF site and the sewer line alignments, no

desert tortoise were identified with project areas of potential effect. Refer to Appendix 4 for a

complete species list and discussions of other sensitive animal species.

Regulatory Setting

The key federal law related to these issues is the Historic Sites Act of 1935, which established a

national registry of natural landmarks and protects “outstanding examples of major geological

features.”

Hazards as they relate to public safety are also concerns for project design. Of primary importance

to the project area is that of seismic hazards. The anticipated Maximum Credible Earthquake (MCE)

and location of fault zones are important criteria that drive the design and retrofit of structures. The

state, county and local hazards overlays are used to assess the risks of proposed projects.

Affected Environment

Geologically, the project area and surrounding vicinity are at the boundary of the

Transverse Ranges and the Mojave Desert Geomorphic Provinces. The hills and mountains trend in

an eastwest direction, with the Pinto and Eagle Mountains to the east and the Santa Monica and

Santa Ynez Mountains to the west. The immediate valley in the Town of Yucca Valley is bounded by

the Little San Bernardino Mountains on the south and the Sawtooth Mountains to the north. The

valley floor contains Quaternary alluvial deposits and older superficial sediments, including sand and

gravel eroded from the adjacent highlands. Alluvial soils consist of unconsolidated sand and gravel

with minor amounts of clay and silt, estimated to be 100 feet or less in thickness. Older alluvium

consists of coarse-grained sediments, including cobbles, pebbles and coarse sand. This alluvium

extended to greater than 500-foot depth, particularly in the north and east (General Plan EIR 1995).

The existing fault that represents the greatest local threat in the project area is the Pinto Mountain

Fault, with an estimated maximum Richter magnitude earthquake event of 7.4 and peak ground

acceleration of 0.60 (g), with an estimated duration of strong ground shaking of 31 seconds. The

proposed WRF project is not located within a mapped fault rupture zone or Alquist-Priolo Special

Studies Zone (Seismic Safety Element of the General Plan, Exhibit V-1, 1995). The sewer pipeline

alignments will cross the Pinto Mountain Fault, which is located north of SR 62 and other inferred

faults.

Regional seismicity appears to be dominated by the San Andreas Fault (west of the Morongo Basin)

and the Johnson Valley Fault (the Landers Fault System approximately 3 miles north of Yucca

Valley). Both of these faults run north-south, or northwest-southeast, and pose no direct ground

rupture hazards within the project area. However, the 1992 Landers earthquake on the Johnson

Valley Fault caused “sympathetic ground ruptures” along the Pinto Mountain Fault (Leighton and

Associates, Inc. 1993). This earthquake damaged 40 percent of the District’s subsurface water

distribution lines and over $100 million of other property damage, according to the Seismic Safety

Element of the General Plan (1995). Liquefaction can occur when loose, unconsolidated and

saturated sandy soils are subjected to ground shaking during a seismic event. This causes the soils

to “liquefy.” This is not seen as a general hazard in the in the Yucca Valley area, due to the depth of

200 feet or more to the groundwater table. In addition, soils within the project area are coarse

alluvial soils, i.e., sandy. Expansive soils are not considered to be a concern in the Yucca Valley, as

these would contain significant amounts of clay. The project area is also located in a “low”

susceptibility zone for rockfalls and landslides (General Plan 1995).

(Omitted without comment)

The desert background consists of typical Joshua Tree woodland and creosote bush scrub alluvial

fan areas with varying levels of human disturbance depending on proximity to the Yucca Valley

urban corridor along SR 62. The proposed project site is located in the near vicinity of SR 62 within

an area developed with mixed residential, commercial, and industrial uses. The SR 62 and SR 247

are designated as “eligible” for official Scenic Highway designation. Additionally, the Town of Yucca

Valley has designated some local routes as Scenic Roadways (General Plan 1995, Exhibit III-13).

According to the General Plan, any projects in the above named scenic corridors need to minimize

impacts on scenic values. The proposed wastewater treatment plant design includes a 1,000-foot

setback or more from SR 62. Night lighting occurs throughout the project area. Individual

residences have exterior night lighting on the outskirts of the town and a combination of street

lights and individual residential lighting occurs within the urban area of the town, i.e., closest to SR

62. Scenic views exist to the north and south to surrounding mountain ranges or ridges, but the

project site itself has no significant or unique visual resources. Development in the surrounding area

creates a human-dominated as opposed to a natural landscape visual setting.

The proposed wastewater treatment plant site is currently vacant. There are individual residences to

the north. These include single-family homes. Generally, the project area can support more housing

development, but this may be limited by location within the Pinto Mountain Fault Zone (where no

new housing is encouraged).

The Town of Yucca Valley 2000 U.S. Census population was 17,200 persons. This was less than that

predicted in area planning at that time. The District’s Water Supply Plan of 1990 (John Egan and

Associates) predicted 26,066-30,428 residents by the year 2000 and 30,250-40,131 by the year

2010 for its service area (which included Yucca Water Company service area). These estimates

assumed a 5 percent annual growth prior to the year 2000, then 3 percent. For the purposes of

planning, household sizes of 2.4-2.5 persons per dwelling unit were used. The Town’s General Plan

studies for the Housing Element (1995) indicated that population growth actually started slowing

from 1990-1993 and the District Urban Water Management Plan estimates annual average growth

from 2005 through 2030 to be about 2.3 percent. The Town had 18,336 persons in 1994, and was

anticipated to have 20,000 by the year 2000. Household sizes were estimated to be similar to those

used by the District, or 2.49-2.5 persons per dwelling unit. The District’s 2005 population estimate

was 26,000 persons based on water services within its service area which is

larger than the Town of Yucca Valley. Other trends that were described in the 1990s were: that the

population would shift from older retirees to younger families with children, and that more multifamily

housing would be developed. Trends have changed, due in part to the loss of population

after the 1992 Landers earthquake, and the more recent increase in population due to military

activities at Twentynine Palms and other area facilities. Overall, however, the population has not

shown the substantial growth forecast envisioned in the 1990s. Buildout was given as 24,401 units

in the General Plan (1995), of which the majority would be single-family housing with zero to 10

dwelling units per acre. In 1995, 79 percent of all housing was of the single-family type. At that

time, there were 8,585 units. The District’s service area encompasses more than the Town of Yucca

Valley, which had 5,366 connections in 1990.

The community contains a mixture of retirees and a service economy geared to serve them. Many

retired residents live on fixed incomes and the majority of the community consists of low to

moderate income residents. The WRF project site is located adjacent to commercial uses at the

north end adjacent to SR 62. A few single family residences and one industrial facility are located in

the immediate vicinity of the project site. These surrounding uses are consistent with those found in

the whole community and no particular unique income or ethnic group is known to occur within the

The construction scenario for the project area has been summarized in the project description, but

some aspects are further discussed in the following text. The main activities related to construction,

that will be evaluated in the environmental consequences section of this report, include: site

clearing, grading, excavation and trenching, and installation of treatment facilities and equipment,

temporary lift station, pump stations, sewer pipelines and the operations building. All work will be

conducted within the identified footprint of the proposed facilities or within disturbed road rights-of

way. Temporary traffic management will be required as pipelines are installed within road rights-ofway.

Construction activities will temporarily affect local traffic in these road rights-of-way, but will

not affect traffic over the long term once the facilities are installed.

The project is located near existing developed areas and, thus, does not involve any need for

extension of any new energy resources. The wastewater reclamation facilities and pump stations will

require electricity to serve the proposed facilities, possible including night lighting and other support

equipment. Southern California Edison (SCE) provides the electricity to serve the proposed WRF and

related support facilities. There will be energy, primarily petroleum products and perhaps some

electricity, consumed by the construction activities. During operations electricity will be consumed,

and the project will have a back up diesel generator to provide power during an emergency loss of

electrical power.

(Omitted without comment)

(Omitted without comment)

(Omitted without comment)

(Omitted without comment)

Please refer to the discussion of biological resources, in Section 3.6.1. The site specific biological

surveys resulted in the finding that no state and federal listed species occur at the WRF site or along

any of the sewer pipeline alignments.

wastewater treatment plant site appears to be located immediately east of this wash. In addition,

the proposed site is located within the 100-year floodplain of this channel, which originates in the

the project area of potential impact. The pertinent Federal Emergency Management Agency (FEMA)

map of the project area is provided in Appendix 6.

(Omitted without comment)

(Omitted without comment)

(Omitted without comment)

(Omitted without comment)

(Omitted without comment)

(Omitted without comment)

(Omitted without comment)

(Omitted without comment)

(Omitted without comment)

(Omitted without comment)

(Omitted without comment)

(Omitted without comment)

(Omitted without comment)

All projects involving a federal action (funding, permit, or land) must comply with Executive Order

agencies to take the appropriate and necessary steps to identify and address disproportionately high

and adverse effects of federal projects on the health or environment of minority and low income

populations to the greatest extent practicable and permitted by law.

The project site is not located in a neighborhood that suffers from exposure to adverse human

health or environmental conditions. There are no major industrial activities or sites in the area. The

top employers generally are related to the school district, health care services and retail stores.

Yucca Valley is still mostly a community with a lower than normal average annual income, due in

part to retirees and part-time residents (seasonal).

(Omitted without comment)

The EPA’s Sole Source Aquifer (SSA) Program was established under Section 1424(e) of the Safe

Drinking Water Act (SDWA). Since 1977, it has been used by communities to help prevent

contamination of groundwater from federally-funded projects. The SSA program allow for EPA

environmental review of any project which is financially assisted by federal grants or federal loan

guarantees. Although nine sole source aquifers have been designated in California, the Warren

Valley Groundwater Basin is not listed among these aquifers as of January 29, 2009. Groundwater

is located several hundred feet beneath the project area of potential impact. The District obtains its

water supply entirely from the Warren Valley Groundwater Basin. Although this Basin is the

District’s sole source of water supply, the aquifer is not designated by the federal EPA as a “sole

source aquifer.”

The land use designations on the properties adjacent to the project area of potential impact consist

of a mix of commercial, industrial, and residential uses. Roads to be affected by the WRF project

component include SR 62, Avalon Avenue, and Indio Avenue. Public access exists to all of the

project area of potential impact, although graded dirt, unpaved, roads are common in the area. The

vast majority of the proposed sewage collection system will be installed in these roadways and

access is generally excellent to all of the proposed collection system pipelines. The project site for

the WRF is currently a large area of open space that is considered valuable. This site is along the

SR 62, which is designated as “eligible” for official Scenic Highway designation. The project is

considered compatible with surrounding uses.

On February 3, 1999, President Clinton signed Executive Order 13112 requiring federal agencies to

combat the introduction or spread of invasive species in the United States. The order defines

invasive species as any species, including its seeds, eggs, spores, or other biological material

capable of propagating that species, that is not native to that ecosystem whose introduction does or

is likely to cause economic or environmental harm or harm to human health. The California noxious

weed list can be used to define the invasive plants that must be considered as part of the analysis

for this project.

Much of the project area has been disturbed, and contains non-native plant and animal species.

The urbanizing portion of Yucca Valley abuts undeveloped desert habitat. Landscaping around

residences is the primary cause of introduced plants (in other locales it might be agricultural

practices). Residential “pets” such as dogs and cats are common. These are of concern, as they

prey on native birds and mammals. Invasive species occur throughout the project area, including

the WRF site. The biological survey contained in Appendix 4 lists the species found in the project

area that fall under this category.

The proposed project, the construction and installation of a wastewater treatment plant;

approximately 405,800 lineal feet of trunk sewer line of varying diameter (see Table 2-5); and three

pump stations are intended to provide the District’s service area with a wastewater treatment and

collection system that must be installed to protect and enhance groundwater quality.

Implementation of the proposed project will cause both temporary and permanent changes to the

physical environment during construction; however, the addition of the proposed wastewater

system infrastructure is essential to the District to continue meeting the public health and safety

requirements for water quality within its service area. Based upon the existing environmental

conditions outlined above in the “Affected Environment” discussion, this section of the Initial

Study/Environmental Assessment (IS/EA) evaluates the effects of the project on the physical and

human environment. The Environmental Consequences section is presented in the same order as

the issues are presented in the previous discussion. The following issues are evaluated by using the

questions posed for each issue in the standard California Environmental Quality Act (CEQA) Initial

Study Environmental Checklist Form, which is included after the text portion of this document.

(Omitted without comment)

(Omitted without comment)

(Omitted without comment)

(Omitted without comment)

(parts a and b were not part of this document and the preamble was Omitted without comment)

(Additional parts are Omitted without comment)

This measure is considered sufficient to reduce the project’s contributions to GHG emissions to the

maximum extent feasible. It will also assist with creation of a visual buffer between the WRF and

surrounding land uses.

(there were no parts a, b, and c. all else was Omitted without comment)

Use of construction equipment may result in some temporary and localized odors from use of diesel

fuels. In addition, the wastewater treatment facilities and pump stations to be constructed as part of

the proposed wastewater treatment plant and sewer system have the potential to generate odors.

However, as described on page 10 of this document, specific odor control systems will be installed

to control odors from each of the potential odor sources. These odor control systems are standard

systems that are used at all WRFs and they are effective, except during upsets or accidents.

Regardless, due to their distance from the existing residential development, potential offsite impacts

are forecast to be less than significant. There are typical concerns from residents that a wastewater

treatment facility causes significant

There are typical concerns from residents that a wastewater treatment facility causes significant

odor effects. This is most commonly based on the assumption that the plant is handling material

that has natural odors and that these odors will be propagated by the treatment plant operation.

This is an incorrect assumption for ongoing, routine plant operations. When operating properly, such

plants typically have an earthy/musty odor, but not a sick, anaerobic decomposition odor. During

upset conditions, a plant can generate such odors, but the key to odor control is to ensure that

plant operations are managed to eliminate or minimize such upset conditions. The following

mitigation measure shall be implemented to ensure such conditions are minimized and that the local

community is not exposed to adverse odor conditions for any substantial amount of time.

Thus, overall project construction and operation is not forecast to create any significant

objectionable odor impacts. With incorporation of the above odor control measures as part of the

project, the potential project odor impacts can be controlled to a less than significant impact.

Regarding air quality effects, the no project alternative would eliminate all construction and all

operating air pollutant emissions associated with the proposed project. Regarding conformity, the

proposed project can be implemented consistent with the MDAQMD air quality management plans

(AQMPs) and in conformity with the State Implementation Plan (SIP). Because the no project

alternative would not cause any direct emissions in the short-term it would also remain consistent

and in conformity with these plans. However, as nitrate concentrations increase in the future,

treatment of groundwater to remove nitrate would generate emissions from electricity consumption,

and if the Regional Board requires advanced individual treatment units for all existing septic tanks,

the ground disturbance within the community from construction activities would be comparable to

that of the proposed project. Such construction and electricity emissions could be implemented with

comparable mitigation measures to control emissions and remain consistent with the AQMPs and in

conformity with the SIP. Thus, no great benefit for air quality impacts would be achieved. The no

project alternative will not generate any direct emissions so it cannot contribute to existing air

quality violations. Indirectly, future treatment requirements for domestic water supply and

individual advanced treatment systems may indirectly generate emissions. Mitigation measures

comparable to those implemented for the preferred alternative would be sufficient to ensure the

emissions would not contribute substantially to an existing or projected air quality violation or a

cumulatively considerable volume of emissions. Under these assumptions the no project alternative

would also not adversely affect any sensitive receptors.

It is in the area of odors that the no project alternative can eliminate potential adverse effects. The

WRF can be routinely operated without generating noxious odors, but on rare occasions upset

conditions can generate such odors. The only way the no project alternative could generate odors

would again be indirectly, as a result of continuing to rely upon septic tanks. Such systems generate

the same type of anaerobic decomposition odors when they fail. Regardless, a higher potential for

adverse odor effects, although considered less than substantial, will occur at the proposed WRF.

(Note: some parts are omitted because they were not relevant to the discussion.)

The proposed project operations will discharge effluent from the wastewater treatment plant to the

District’s proposed recharge basins. Therefore, since the proposed project will not discharge

wastewater to surface waters, it has no potential to violate surface water quality standards or waste

discharge requirements.

Implementation of these measures will ensure that the proposed project construction activities and

treatment plant operations will be controlled to a sufficient level to prevent significant degradation

of water quality.

Note…no subpart a.

The proposed WRF will generate a higher quality of wastewater effluent, compared to the existing

situation, that will be returned to the groundwater aquifer in the Warren Valley Basin.

Approximately 80% of the effluent delivered to the WRF will be returned to the aquifer through the

percolation ponds (accounts for plant losses and evaporation from the pond). General estimates of

wastewater discharged from septic tank systems reaching the groundwater aquifer are about 50%,

as some of the septic tank effluent remains in the vadose zone and other portions are evaporated or

transpired into the atmosphere. Thus, the proposed project is not forecast to substantially deplete

groundwater supplies or interfere substantially with groundwater recharge. The project will enhance

such supplies and enhance recharge on the WRF property. No mitigation is required.

The existing drainage system for the project area of impact will effectively remain the same. The

proposed pipeline alignments will cross many stream channels, mostly within existing paved or

graded roadways. At some locations, including the stream channel (wash) located onsite, pipelines

will cross either natural or man-made washes. Based on a field review of the sewer pipeline

alignments, there is no wetland located within any of the channels, and it is anticipated that the

only regulatory permits required will be a 1602 Streambed Alteration Agreement from the California

Department of Fish and Game and waste discharge requirements from the Regional Board. Based

on field review of the washes, the surface flows will continue unaltered after the pipelines are placed

below the ground surface. Some minor modification of the channel that crosses the property may be

required, if the channel segment adjacent to the WRF requires hardening to protect the

WRF site from a 100-year flood hazard. It does not appear that channel modifications on the WRF

site will be required because there appears to be sufficient room to install the WRF without

encroachment on the channel, i.e. any flood protection can be installed within upland areas adjacent

to the channel. However, if channel modifications are required, they will consist of hardening the

channel wall adjacent to the WRF to ensure that it will not be eroded and expose the WRF facilities

to flood hazards.

Regarding potential for erosion and siltation, implementation of the SWPPP will control erosion and

sedimentation potential. Because the washes in Yucca Valley are isolated waters of the United

States, it will probably not require a Corps of Engineers Section 404 Permit or a Section 401

certification from the Regional Board because the surface runoff occurs in an isolated basin, which

has no connection to any waters of the United States. However, as noted above, the Regional Board

may require waste discharge requirements (WDR) for this project based on separate Porter-Cologne

requirements. To address any adverse effects of fill requirements or stream bed alterations within

this wash, the following mitigation measure will be implemented:

Implementation of this measure is adequate to reduce any adverse effects to the onsite wash to a

less than significant impact level.

As noted above, the wash on the project site will not be substantially altered and future runoff from

upstream of the site will continue to flow in this wash to the downstream channel. The sewer

pipelines will also cross channels. Where such pipeline crossings occur outside of paved roads, it

may be necessary to obtain regulatory permits from CDFG (1602 Streambed Alteration Agreement)

and the Regional Board (waste discharge requirements, WDR) as outlined under mitigation measure

4.2-4. Regarding runoff from within the WRF, it will be collected in a retention basin and discharged

to the headworks for treatment prior to discharge. Thus, the proposed project is forecast to increase

runoff from the existing site when the plant is installed, but the increased runoff is not forecast to

cause a substantial alteration of the existing drainage pattern because the increase runoff will be

retained and treated within the WRF itself. During construction the modified runoff will require

implementation of the mitigation measures (4.2-1 through 4.2-3) identified above to control

downstream water quality impacts. With implementation of these measures the potential for

significant adverse impacts will be controlled to a less than significant impact level.

This project will not increase the peak discharge of surface runoff to the existing drainage area or

provide a substantial additional source of polluted runoff. This finding is based on the fact that

runoff from within the treatment plant site will be collected and returned to the plant for treatment

before discharge. No mitigation is proposed.

With implementation of the SWPPP and WQMP, the identified BMPs as outlined above, the project

construction activities are not forecast to have any potential to substantially degrade surface water

quality. Over the long-term the data indicates that percolation of the treated effluent or reuse as

recycled water will not cause any substantial degradation within the Warren Valley Groundwater

Basin. The analysis provided in the U.S. Geological Survey technical report in Appendix 3 verifies

this finding is available upon request to the District. No mitigation is required beyond that already

identified for the SWPPP and WQMP. The U.S. Geological Survey modeled the potential for recharge

of the treated effluent into the onsite recharge ponds to assess future impacts to groundwater levels

and groundwater quality under future discharge scenarios. Appendix 3 contains more detailed

information regarding the model, model assumptions and the model runs. The assumptions included

the assumed future effluent flows, effluent water quality, percolation pond sizes and groundwaterlevel

threshold. The model conducted several 16-year simulations of the effects of the proposed

project on the upper/middle aquifers, the lower aquifer and the deep aquifer. Year 2008 pumping

and recharge patters were used in the model-calibration process.

The following model results were reported in the U.S. Geological Survey evaluation. The simulated

future water levels were determined to not reach the water level threshold of 100 feet below the

ground surface (bgs) after 16 years of recharge. Therefore, no new production wells are needed to

control water levels during the 16-year simulation period. However, the simulated rate of water

level rise indicates that the water-level threshold will be exceeded in the future if wastewater

recharge is continued and there is no pumpage from the East hydrogeologic unit. Therefore, wells

will need to be installed in the future to ensure the 100 foot bgs threshold is not exceeded. An

adaptive mitigation measure for this impact is presented below.

The modeling for water quality parameters concluded that the maximum simulated Total Organic

Carbon (TOC) concentration was about 9 mg/L in the upper/middle aquifer; 0.5 mg/L in the lower

aquifer. The maximum nitrate (NO3) concentration was about 35 mg/L in the upper/middle aquifer

and about 2 mg/L in the lower aquifer. The maximum simulated Total Dissolved Solid (TDS)

concentration was about 420 mg/L in layer 1 and about 300 mg/L in layer 2. The NO3 concentration

is approaching the maximum contaminant level (MCL, 45 mg/L for NO3), but it does not exceed the

MCL. The modeled TDS concentration does not exceed the secondary MCL for TDS, which is 500

mg/L. Based on the modeled data, the groundwater quality downstream of the WRF recharge

ponds will

be degraded relative to the existing concentrations, but it is not forecast to exceed public drinking

water standards. Because the public health will be protected by operation of the proposed WRF, the

project is not forecast to cause significant degradation of the existing groundwater quality in the

groundwater aquifer downstream of the WRF site. Adaptive mitigation to ensure that maximum

contaminant levels for public drinking water standards are not exceeded in the groundwater in the

future.

With implementation of these measures, the water quality of the groundwater aquifer affected by

the proposed project will not be degraded to a level of significant adverse impact.

The project does not propose new housing but a portion of the WRF project site is within a 100-year

flood hazard area. According to the Yucca Valley General Plan, the wastewater treatment plant site

and pipeline alignment are in a “A” zone, for 100-year flood hazard potential. Based on the current

site design, the treatment plant will be installed outside of or just on the eastern edge of the flood

hazard zone. To ensure no damage from 100-year flood hazards, the proposed treatment plant will

have to be protected from the 100-year flood hazard by elevating the facility above the 100-flood

level or by armoring the facility from exposure to such hazard. Mitigation is provided below to

accomplish this.

Implementation of this measure is adequate to reduce any adverse effects to the treatment facilities

from onsite flood hazards.

See the analysis provided in 4.2.g above.

Based on the analyses in the three sections preceding this one, the proposed project has no

potential to expose either people or structures to substantial loss or injury related to flooding,

including failure of a levee or dam. No such existing facilities occur within the upstream area of the

proposed project. No mitigation is proposed.

There are no water bodies or sources of inundation for the project area by seiche or tsunami. As

within any desert environment, storm runoff can incorporate a substantial amount of sediment and

a “flash flood” event can transport large volumes of sand and rocks, which is comparable to a

mudflow. The mitigation required under issue g. above must include a “bulking” factor as part of the

design to protect the treatment plant facilities from damage from such flows.

Regarding hydrology and water quality effects, the no project alternative would eliminate all

construction and all operating activities associated with the proposed project. However, the

rationale for installing the WRF is the nitrate contamination caused by historic disposal of

wastewater to subsurface septic tank leach systems. Thus, the no action alternative has a higher

potential to contribute to or cause violation of water quality standards and to continue degrading

water quality than the proposed project. This water quality standard violation is an adverse impact

that would be substantial and non-mitigable, including potentially substantial adverse public health

effects on the resident population of the District’s service area.

The no project alternative would eliminate the modifications at the project site that are exposed to

flood hazards. It is possible to mitigate these effects on the proposed WRF to a less than substantial

level, but the no project alternative would eliminate these impacts from both a direct and indirect

standpoint.

The no project alternative would also eliminate the exposure of structures to any flood hazards or

mudflows. Neither project alternative would be exposed to seiches or tsunamis.

The no project alternative would eliminate the modifications at the project site that could result in

erosion, sedimentation and other pollution. It is possible to mitigate these adverse effects on the

environment to a less than substantial level, but the no project alternative would eliminate these

impacts from both a direct and indirect standpoint at the project site and along the pipeline

alignments.

(Note that some parts of this sub-section have been omitted to focus on the part being questioned

or in need of other action.)

As described in the water quality discussion above, the proposed project will be subject to

wastewater discharge requirements from the Colorado River Basin Regional Board, which must be

met or the wastewater treatment facility cannot operate. As further discussed in Section 4.2 above,

the WRF has been specifically designed to meet the anticipated waste discharge requirements. All

effluent from the proposed wastewater treatment facilities will be discharged to the District’s

recharge basins and percolated into the local groundwater aquifer. The analysis of the water quality

impacts to the Warren Basin groundwater resources is also presented in Section 4.2 above and

determined to be a less than significant adverse impact. The non-point source discharges from the

project will be from construction activities and they will be managed under the mitigation measures

already identified in Section 4.2. Through implementation of the SWPPP and WQMP and use of

identified BMPs for this project, no violations of any water quality objectives or wastewater

treatment requirements is forecast to occur from implementing the proposed project. No additional

mitigation is proposed.

As described in Section 4.2, stormwater flows within Yucca Valley may be altered by installation of

the sewer pipelines or the proposed WRF. To address potential impacts to stormwater flows during

construction, this document requires mitigation through effective implementation of best

management practices during construction and operation. Once the pipelines are installed beneath

roadways or across channels, no change in stormwater flow is forecast to occur during operation as

a result of installing the sewer collection system. As described in Section 4.2, stormwater flow

generated within the proposed WRF project site would continue to be discharged to the existing

stormwater surface drainage system. No change in offsite downstream drainage facilities will be

required from implementing the proposed project. Temporary stormwater management measures

will be implemented during construction of the pipeline and wastewater treatment facilities. Longterm

modification of the onsite portion of the existing dry wash that crosses the property will be

required, including either rerouting the flows around the facilities or providing for continued flow of

bulked storm flows through the property. No potential exists to require new major public

stormwater facilities to be constructed or expanded downstream of the project site. No significant

impact is forecast to occur and no mitigation is required.

The no project alternative would continue to contribute to water quality degradation in the Warren

Valley Basin and to the potential exceedances of the nitrate standards in the future. The proposed

project would constitute a major step in eliminating this water quality degradation. Thus, the no

project alternative has a more substantial adverse effect on exceeding wastewater treatment

requirements than the proposed project.

The no project alternative would not include any direct construction of water or wastewater

facilities. As indicated above, the no project alternative indirectly has a potential to cause

construction of new water treatment facilities and perhaps to require the installation of a large

number of advanced individual treatment systems if the preferred alternative is not implemented.

Thus, the no project alternative may also mandate construction of such facilities that could cause

adverse environmental effects. Based on available mitigation, these no project facilities can

probably avoid significant effects, but this could only be determined on a case-by-case evaluation in

the future. Regarding capacity of wastewater treatment providers, the no project alternative has the

same effect as the proposed action because no existing wastewater treatment provider exists within

the District’s service area at this time. The no project alternative would eliminate any need to

construct stormwater drainage facilities at the WRF site. Although the proposed action would not

cause any substantial adverse effects related to stormwater management issues, the no project

alternative would have less impact because it will not require any modification to such facilities.

Regarding sufficient water supplies, the no project alternative would eliminate any direct demand

for local water supplies. However, over the long-term the implementation of the no project

alternative would continue the current path of degrading the Warren Valley Basin aquifer and this

would cause a substantial adverse impact to water supplies for existing and future uses. Therefore,

the no project alternative’s potential effects on water supplies is concluded to be substantial and

more adverse than the proposed action. Under the no project alternative, the wastewater effluent

solids are managed by individual subsurface septic tank/leach systems. Periodically, all septic tanks

must be pumped and the waste is delivered to a landfill for management. Similarly, the solids from

the WRF will be stabilized at the facility, and then disposed of to a landfill, to a composting facility,

or directly to end users. Because of the increased potential for recycling wastewater effluent solids

from the proposed action, it has a lower environmental effect on solids management than the no

project alternative.

(Omitted with no comment)

(Omitted with no comment, including sub elements)

(Omitted without comment, including all sub-elements, except those remaining with comment.)

There is currently no adopted Habitat Conservation Plan, Natural Community Conservation Plan, or

other approved local, regional, or state habitat conservation plan associated with the proposed

project site. Therefore, no mitigation measures need to be implemented and the project’s impacts

on such resources will be nonsignificant without mitigation.

The no project alternative would eliminate all potential to disturb listed or sensitive species, and

would also eliminate the permanent loss of up to 30-35 acres of low quality creosote bush scrub

habitat at the WRF site and the pump station locations. Approximately 10 acres of this habitat will

be disturbed as a result of installing the pipelines that will cross stream channels. The stream

channel disturbances and these impacts and requirement to obtain regulatory permits would also be

eliminated under this alternative. Over the long-term the indirect effects of requiring installation of

water treatment units to remove nitrate may cause the permanent loss of several acres of creosote

bush habitat. Mitigation available for the proposed action would be sufficient to control future

indirect adverse effects of the no project alternative to a less than substantial level, comparable to

the proposed project.

The no project alternative would also eliminate any interference with movement of wildlife, conflicts

with local policies protecting biological resources, or conflicts with adopted habitat management

plans. No such plans apply to the project area.

this subsection have already been questioned regarding the assumptions that lack science and are

assumed rather than tested.)

With implementation of the above measure, the proposed project will not subject humans to

potential substantial adverse geologic constraints/effects, including the risk of loss, injury, or death

involving rupture of a known earthquake fault or strong seismic ground shaking. Measures to meet

this seismic mitigation measure include enhanced foundation support; use of higher quality

materials and more steel in the structures; and other similar measures that ensure the proposed

WRF can function after a major seismic event. In addition, the proposed project is not located on

steep slopes and is also not subject to landslides. There is little potential for liquefaction to occur in

the project area, as depth to groundwater has been identified by the U. S. Geological Survey to be

over 100 feet below the ground surface.

The 1995 Town of Yucca Valley Comprehensive General Plan, Seismic Safety Element Exhibit V-1,

identifies two other local faults with identified Alquist-Priolo Special Studies Zones, the Eureka Peak

Fault located west of the project site and the Burnt Mountain Fault, located west of the Eureka Peak

Fault. Although these faults appear not to pose a rupture hazard for the WRF, the sewer collection

system will cross these faults, in addition to the Pinto Mountain Fault. Future pipelines crossing any

of these fault zones may experience damage from rupture associated with future seismic events on

these faults. Mitigation is provided to address the future management of such damage to sewer

pipelines crossing the three faults’ Special Studies Zones.

With implementation of the above measure, the potential degradation to the environment from fault

rupture damage to the sewer collection pipelines crossing the identified Special Studies Zones can

be controlled to a less than significant impact level.

The proposed action would construction and operation the WRF and a sewer collection system. By

eliminating these facilities, the no project alternative eliminates the potential to expose structures

and sewer pipeline to seismic or other geological hazards. This alternative also eliminates any direct

soil erosion or sedimentation effects. Indirectly, future water treatment facilities and individual

advanced subsurface systems will also disturb a substantial amount of land, which can also cause

erosion and sedimentation. Available mitigation can control such impacts to a less than substantial

level.

The no project alternative would have substantially greater impacts due to continued septic tank

failures within shallow soils and soils with subsurface hardpan layers which contribute to such

failures. The potential impacts from the no project alternative due to such soils is considered to be a

substantial adverse impact.

(Omitted without comment)

The sewer collection system pipeline installation will not change land uses, or cause any

aboveground visual impacts. The WRF site will change from open space with desert vegetation to

above ground wastewater treatment facilities and recharge basins. The above ground facilities

proposed would be located within an area that already contains interspersed developed lots, both

residential and industrial. The proposed WRF facilities will be approximately the same height as

surrounding structures and facilities, but will exhibit greater mass. In addition, the above ground

facility will become part of the existing suburban setting. These changes in the visual setting after

development of the WRF will be adverse, but the degree of change at the WRF site and surrounding

area is not considered to substantially adverse. No significant adverse impact to scenic vistas will

occur on an area-wide basis.

(Omitted without comment)

This project is the construction and installation of wastewater treatment facilities, which are

intended to improve the quality of regional groundwater supplies through the removal of septic

tanks. It is intended only to provide services for existing and planned development. There is a

limited potential for the provision of sewer service to encourage undeveloped parcels to develop

within the Town of Yucca Valley. However, without the proposed project, those parcels could be

developed anyway by installing advanced onsite wastewater septic systems where the proposed

system is designed to remove no less than 50 percent of the nitrogen released in the effluent

(Advanced Treatment, denitrifying systems). Costs for such systems are more expensive than the

cost of hooking up to the District’s WRF system, but they do provide an opportunity for development

that is feasible.

The type and density of development in the District’s service area is controlled by land use

designations established by the agencies having jurisdiction over such issues; in the project area

the Town of Yucca Valley controls land use. As such, this project is considered growth

accommodating, not growth-inducing, in that it will help provide sewer service to development that

is approved or allowed by the agencies having jurisdiction over land use issues. Since an

alternative means of treating sewage (individual advanced treatment, denitrifying systems) is

available that would allow for development of vacant parcels, the proposed sewer system does not

constitute or eliminate an unavoidable cap or constraint on future development.

The potential for growth inducement, discussed in detail in Chapter 6, related to infrastructure

improvements is based on the elimination of some development constraint in place at a given time.

As the discussion above and in Chapter 3 indicates, there are alternative ways to develop parcels of

land within the Town because of the advanced individual subsurface treatment systems, or for large

developments the installation of package treatment systems. Thus, the proposed wastewater

infrastructure collection system is not forecast to result in growth inducement or any growth beyond

that which could occur without the installation of this system. Implementation of the project has no

potential to cause or induce any substantial or significant population growth, directly or indirectly.

The project has no potential to impact any existing housing or cause the displacement of people.

No impact is identified and no mitigation is required. The proposed wastewater treatment facilities

have no potential to adversely impact any low income or ethnic communities, i.e., no environmental

justice impacts.

The no project alternative would have comparable effects on future growth and no known direct

effects on existing housing resources. In a strange turn of events if this alternative were selected, a

consequence could be a short-term moratorium on development, unless the Regional Board would

accept individual advanced wastewater treatment systems for new development or through retrofit

of existing development. Under this scenario the no project alternative could have a more adverse

effect on both the existing and future local population, and possibly housing if abandoned, than the

proposed action.

Construction impacts and related mitigation measures are described in various parts of Section 4 of

this document. Many of the construction impacts addressed in this document are subject to

mitigation and the proposed project can be implemented without any significant adverse short-term

environmental effects. Specifically, air emissions, biological resources, cultural resources, geology

and soil constraints, management of construction hazards, management of construction storm water

runoff, mineral resources, noise, and traffic effects have all been evaluation and determined to not

cause substantial negative environmental effects. Please refer to the discussion of these specific

issues in the pertinent sections of this document.

None of the direct construction impacts attributable to the proposed action would occur under the

no project alternative. If it is assumed that implementation of the no project alternative must result

in installation of individual advanced subsurface treatment systems and nitrate treatment facilities,

some more limited indirect construction impacts would occur under this alternative in the future. As

in the case of the proposed action, available mitigation measures are considered sufficient to reduce

potential no project alternative construction effects to a less than substantial level.

Overall, the project will consume energy during the construction period, with the use of petroleum

based fuels for equipment and vehicles. Electrical energy will be consumed for wastewater

treatment operations and pump stations into the long-term future. An estimated 2.9 million KWhr

of electricity will be required to operate each year, or about 8,000 KWhr per day. According to two

California Energy Commission documents, the “2008 Integrated Energy Policy Report Update” and

the “California Energy Demand 2008-2018 Staff Revised Forecast” adequate energy demand within

the Southern California Edison and Southern California Gas service areas is forecast to grow by

about 1.5% per year between 2008 and 2018. Adequate energy resources are available to serve

the region, based on the assumption that new electricity power generation systems will be installed

at an accelerated rate in accordance with the demand forecasts. Based on these reports, adequate

energy resources can be made available to support forecast growth within the project area, which is

located in both company’s service areas. Thus, adequate electricity resources are assumed to be

available from Southern California Edison to support operation of the WRF. The greenhouse gas

(GHG) emissions related to electricity consumption are presented and determined to be a less than

substantial adverse effect in Sub chapter 4.1. Thus, the proposed WRF use can be served through

existing energy resources, such that energy impacts should be minimal.

(Omitted because of no argument for the entire Alternative…starting at 4.17 comments are as

given)

(Omitted without comment)

The project site is located within a community that is generally below the economic level of other

communities in the County, due to having a high percentage of retirees and seasonal residents.

However, there are no industries or contaminated sites in or around the project area such that this

project would comprise a new hazard and additional hazard to a particular population. The proposed

project will temporarily impact those residents along the pipeline routes and in the vicinity of the

treatment plant, but it has no potential to adversely impact any low income or ethnic communities

in the long term. The project itself will be an improvement to area services that will benefit the

population.

Due to the type of infrastructure project envisioned by the proposed action, no environmental

justice issue have been raised by implementing proposed action. For the no project alternative no

direct environmental justice issues have been identified. However, if it is assumed that

implementation of the no project alternative may result in continued contamination of groundwater

within the District’s service area by nitrates and other constituents of the septic tank discharges,

then the whole community, including those seniors and low-income residents could be substantially

impacted by being forced to spend substantially more of their dollars for drinking water in the

future.

(Omitted without comment)

(Omitted without comment)

Colorado River Hydrologic Region California’s Groundwater

Warren Valley Groundwater Basin Bulletin

The Warren Valley Basin is located in the northwestern portion of the

Colorado Desert Hydrologic Study Area. This basin includes the waterbearing

sediments beneath the town of Yucca Valley and the surrounding

area. The northern boundary of the basin is the Pinto Mountain fault and the

southern boundary is the bedrock outcrop of the Little San Bernardino

Mountains. The Warren Valley Basin is bounded on the east by a bedrock

constriction called the “Yucca barrier” and on the west by a bedrock

constriction and a topographic divide between Warren Valley and Morongo

Valley. Precipitation in this basin ranges from 8 to 12 inches per year, with

an average rainfall across the basin of about 10 inches (USDA 1999).

The productive water-bearing materials in this basin consist of

unconsolidated to partly consolidated Miocene to Quaternary continental

deposits (Mendez and Christensen 1997). The continental deposits

regionally are interpreted to range up to 10,000 feet in thickness (Moyle

1984); however, wells in Warren Valley Basin reach as deep as 1,610 feet

without encountering bedrock. Geophysical studies suggest that the Warren

Valley Basin may exceed a depth of 2,000 feet (Whitt and Jonker 1998).

The main productive water-bearing deposits are unconfined interbedded

gravels, conglomerates, and silts deposited in alluvial fan systems (Schaefer

1978, BEE 1994). These deposits have an average of about 11 percent

specific yield (Lewis 1972) and well yields up to 4,000 gpm.

The Pinto Mountain fault zone juxtaposes alluvial valley fill material against

consolidated bedrock. Data to evaluate whether this fault is a barrier to water

at the boundary of the Warren Valley Basin is sparse, but the Pinto Mountain

fault is a barrier to groundwater flow toward the east at the Copper Mountain

Valley Basin - Joshua Tree Basin boundary (Mendez and Christensen 1997).

A north-trending basement high causes a sharp change in water level

between the towns of Yucca Valley and Joshua Tree, showing a drop of

about 400 feet to the east (“Yucca barrier” of Lewis 1972).

Natural recharge to the basin is mainly from direct percolation of

precipitation and percolation of ephemeral streamflow from Water Canyon in

the north and Covington Canyon in the south (BEE 1994; Mendez and

Christensen 1997; Whitt and Jonker 1998). Lewis (1972) suggests that

annual recharge may not exceed 200 af, but actual recharge amounts are

poorly constrained and quite variable from year to year. Some minor inflow

may come from groundwater moving through fractures in the adjacent

Colorado River Hydrologic Region California’s Groundwater

Warren Valley Groundwater Basin Bulletin 118

Last update 2/27/04

bedrock. Percolation of septic tank effluent also contributes to recharge of

groundwater. State Water Project water delivered via the Morongo Basin

Pipeline provides recharge through spreading grounds near the Yucca Valley

Airport (Hanson 1999).

Hydrographs of wells in the Warren Valley Basin show water levels in 1998

above the 1986 levels (Hanson 1999). Most hydrographs show a general

lowering of water levels from 1986 through about 1992 and then recovery of

water levels through 1998. The range in elevation of water levels is up to

220 feet since 1986 (Hanson 1999). Groundwater in the Warren Valley

Basin appears to flow northward from the Little San Bernardino Mountains

to the Pinto Mountain fault and then east toward Twentynine Palms (Lewis

1972; Mendez and Christensen 1997). Groundwater flows eastward across

the “Yucca barrier,” a subsurface structure associated with an eastward

lowering of groundwater water levels into the Joshua Tree Basin (Lewis

1972).

groundwater in storage in 1958 using a saturated thickness of 150 feet, a

specific yield of 11percent, and an area of 6,400 acres. Lewis (1972)

assumed that prior to 1948, groundwater levels were probably static. If so,

then this storage value would represent a steady-state basin under natural

conditions. According to Lewis’ maps, additional storage space is available

above the water levels of 1958. A total storage capacity of about 568,000 af

for the Warren Groundwater Basin can be estimated using an area of 17,200

acres, an average specific yield of 11 percent, and an average total thickness

of 300 feet.

groundwater in storage in 1958 using 150 feet saturated thickness, 11percent

specific yield, and 6,400 acres. The annual report of the Warren Valley

Basin Watermaster (Hanson 1999) does not determine available storage.

Not enough data exist to compile a detailed groundwater budget for this

basin. For the 1998-1999 water year, total extraction amounted to 2,201 af

which includes 312 af pumped by the Blue Skies Country Club mainly for

irrigation of a golf course (Hanson 1999). HDWD recharges State Water

Project water, which amounted to 2,237 af for water year 1998-1999 (Hanson

1999). An estimate of natural recharge rate for this area was determined to

be about 2.8 percent of precipitation by Whitt and Jonker (1998). Using the

area of the watersheds for the basin, the reported precipitation, and a 2.8

percent recharge rate, the natural recharge for water year 1998-1999 is

estimated to be about 330 af.

District (HDWD 2000) indicates that the average water has calcium-sodium

bicarbonate character. Total dissolved solids concentration ranges from 129

Colorado River Hydrologic Region California’s Groundwater

Warren Valley Groundwater Basin Bulletin 118

Last update 2/27/04

some wells in the Warren Valley Basin (BEE 1994).

Inorganics – Primary 18 1

Radiological 18 1

Nitrates 18 5

Pesticides 16 0

VOCs and SVOCs 16 0

Inorganics – Secondary 18 3

program from 1994 through 2000.

second detection above an MCL. This information is intended as an indicator of the

types of activities that cause contamination in a given basin. It represents the water

quality at the sample location. It does not indicate the water quality delivered to the

consumer. More detailed drinking water quality information can be obtained from the

local water purveyor and its annual Consumer Confidence Report.

Municipal/Irrigation Range: 10 - 4,000 Average: 350 (25

wells)

Domestic

Municipal/Irrigation

Hi Desert WD Groundwater

levels.

17 wells/monthly (Brown 2000).

Hi Desert WD Minerals, organic

and inorganic

chemicals.

11 wells/quarterly (Schwab

2000).

Hi Desert WD Coliform. 11 wells/weekly (Schwab 2000).

U.S. Geological

Survey

Quality 7

U.S. Geological

Survey

Groundwater

levels.

10

Colorado River Hydrologic Region California’s Groundwater

Warren Valley Groundwater Basin Bulletin 118

Last update 2/27/04

Groundwater management: The Hi Desert WD is the court appointed

watermaster for this adjudicated basin. The

Warren Valley Basin Management Plan was

adopted in 1991 (Hanson 1999).

Water agencies

Public Hi Desert WD, Mojave Water Agency.

Private

Akers, J.P. 1986. Geohydrology and Potential for Artificial Recharge in the Western Part of

the U.S. Marine Corps Base, Twentynine Palms, California, 1982-83. U.S. Geological

Survey Water-Resources Investigations Report 84-4119. 18 p.

Bader, J.S. 1963. Effect of Faulting in Alluvium on the Occurrence, Movement, and Quality

of Ground Water in the Twentynine Palms Area, California (abstract). Geological

Society of America Special Paper 73. 22 p.

________. 1966. Records of Water Level and Pumpage in Joshua Tree National Monument,

California. U.S. Geological Survey Open-File Report. 3 p.

Bookman-Edmonston Engineering Inc. (BEE). 1994. Regional Water Management Plan.

Mojave Water Agency, Apple Valley, California. 135 p.

Brown, J. 2000. Hi Desert Water District. Telephone conversation with R.R. Davis

(Department of Water Resources), August 22, 2000.

California Department of Water Resources (CDWR). 1960. Data on Water Wells and Springs

in the Yucca Valley-Twentynine Palms Area, San Bernardino and Riverside Counties,

California. Bulletin 91-2. 163 p.

________. 1984. Twentynine Palms Ground Water Study. Southern District Report. 109 p.

Downing, D.J. 1974. Records of Water Level and Pumpage for 1973 in Joshua Tree National

Monument, California. U.S. Geological Survey Open-File Report. 15 p.

________. 1977. Ground-Water Data for 1974-75 in Joshua Tree National Monument,

California. U.S. Geological Survey Open-File Report 77-80. 34 p.

________. 1978. Ground-Water Data for 1976-77 in Joshua Tree National Monument,

California. U.S. Geological Survey Open-File Report 78-854. 34 p.

Freckleton, J.R. 1982. Ground Water in the Twenty-Nine Palms Indian Reservation and

Vicinity, San Bernardino County, California. U.S. Geological Survey Water-Resources

Investigations Report 82-4060. 46 p.

Hanson, J.C. 1999. Annual Report of the Warren Valley Basin Watermaster for Water Year

1998-99. Yucca Valley, California: Hi Desert Water District.

Hi Desert Water District (HDWD). 1999. 1998 Annual Water Quality Report. April 1999.

Yucca Valley. 2 p.

Hi Desert Water District (HDWD). 2000. WaterNotes: Annual Water Quality Report. June

2000. Yucca Valley. 4 p.

Lewis, R.E. 1972. Ground-Water Resources of the Yucca Valley-Joshua Tree Area, San

Bernardino County, California. U.S. Geological Survey Open-File Report. 51 p.

Mendez, G.O. and A.H. Christensen. 1997. Regional Water Table (1996) and Water-Level

Changes in the Mojave River, the Morongo, and the Fort Irwin Ground-Water Basins,

San Bernardino County, California. U.S. Geological Survey Water-Resources

Investigations Report 97-4160. 34 p.

Miller, G.A. 1968. Test-Drilling and Pumping-Test Data, Joshua Tree National Monument,

California, 1968. U.S. Geological Survey Open-File Report. 13 p.

Colorado River Hydrologic Region California’s Groundwater

Warren Valley Groundwater Basin Bulletin 118

Last update 2/27/04

________. 1970. Records of Water Level and Pumpage for 1969 in Joshua Tree National

Monument, California. U.S. Geological Survey Open-File Report. 17 p.

________. 1971. Records of Water Level and Pumpage for 1970 in Joshua Tree National

Monument, California. U.S. Geological Survey Open-File Report. 16 p.

________. 1972. Records of Water Level and Pumpage for 1971 in Joshua Tree National

Monument, California. U.S. Geological Survey Open-File Report. 17 p.

________. 1973. Records of Water Level and Pumpage for 1972 in Joshua Tree National

Monument, California. U.S. Geological Survey Open-File Report. 17 p.

Moyle, W.R., Jr. 1974. Geohydrologic Map of Southern California. U.S. Geological Survey

Water-Resources Investigations Report 48-73.

________. 1984. Bouguer Gravity Anomaly Map of the Twentynine Palms Marine Corps

Base and Vicinity, California. U.S. Geological Survey Water-Resources Investigations

Report 84-4005.

Schaefer, D.H. 1978. Ground-Water Resources of the Marine Corps Base, Twentynine

Palms, San Bernardino County, California. U.S. Geological Survey Water-Resources

Investigations Report 77-37. 29 p.

Schwab, S. 2000. Hi Desert Water District. Telephone conversation with R.R. Davis

(Department of Water Resources), August 22, 2000.

Weir, J.E., Jr., and J.S. Bader. 1963. Ground Water and Related Geology of Joshua Tree

National Monument, California. U.S. Geological Survey Open-File Report. 123 p.

Whitt, A. and K. Jonker. 1998. Groundwater Survey of the Joshua Tree and Copper

Mountain Subbasins, Joshua Tree, California. Consultant’s report prepared by Western

Water Surveys for Joshua Basin Water District.

Changes made to the basin description will be noted here.