“Water-quality analyses indicate that septage from septic tanks is the primary source of the high-nitrate concentrations measured in the Warren groundwater basin.” - USGS; Water-Resources Investigations Report 03-4009; Evaluation of the Source and Transport of High Nitrate Concentrations in Ground Water, Warren Sub basin, California.
A growing concern
According to a United States Geological Survey studies, from the late 1940s through 1994, water levels in the Warren sub-basin declined as much as 300 feet due to groundwater extraction. In response, the Hi-Desert Water District instituted an artificial recharge program in 1995 to replenish the groundwater basin using imported California State Water Project water. The artificial recharge program resulted in water-level recovery of about 250 feet between 1995 and present; however, Nitrate (NO3) concentrations in some wells also increased from 10 mg/L to more than the U.S. EPA maximum contaminant level of 44 mg/L due to the accummulation of nitrates in the soils from years of septic system discharge. The USGS continues to study and monitor the basin, collecting data and updating a computerized groundwater model.
Over 10,000 households and businesses in Yucca Valley currently dispose of their wastewater using individual sewage disposal systems, or septic tanks. Studies by USGS have confirmed these septic tanks are the cause of high nitrate levels. Continued contamination by these septic systems could negatively impact Yucca Valley’s water supply. Recent USGS studies have indicated that nitrates from septic systems have already percolated to a depth of at least 150 feet in the older part of Yucca Valley.
Commitment to protecting the groundwater
To protect the water supply from potential contamination the District is working in conjunction with the California Regional Water Quality Control Board in the development and construction of the Wastewater Treatment and Water Reclamation Facility. In fact, the Regional Water Quality Control board has adopted Resolution R7-2007-0074 supporting the priority funding to the wastewater treatment and water reclamation project.
The project includes the construction of a centralized wastewater treatment and water reclamation facility and the associated collection pipelines from each property to the main facility.
Supplementing existing water supplies
Due to limited natural recharge, District officials have been seeking sources of supplemental water to replenish the groundwater basin to provide for the needs of the community, now and in the future.
Currently, the only groundwater replenishment sources for the District in the Warren Groundwater Basin are the following:
Recharge from natural rainfall. The natural yield of the groundwater basin does not meet current demands for water.
Imported State Water Project water. The District currently purchases water through the Mojave Water Agency from the State Water Project to recharge the groundwater in order to meet current demand.
Both sources of water are being threatened due to recent events including court-ordered restrictions on the amount of water delivered from the State Water Project to Southern California, a long-term drought, population growth, climate change and a below-average snowpack in the Sierra Nevada Mountains. Each of these occurrences impacts the amount of water available to recharge the groundwater basin.
The water reclamation component of the project will provide a supplemental water source. This highly treated water will assist in replenishing Yucca Valley’s groundwater aquifer, which is essential to meet future water demands in the region.
Water treatment technologies
The Project consists of a collection system, wastewater treatment plant and a water reclamation ponds. The objective is to treat the wastewater to a high quality that can be used recharge the groundwater basin. A number of technologies have been considered to treat the wastewater to produce high-quality water, including:
The District is confident in both water reclamation technologies, as they have proven to be very effective in other projects. The Conventional Extended Aeration option is a reliable, proven, cost-effective technology.
High Rate Membrane Bioreactor technology is also an effective process. It is modular, can accommodate plant upgrades, and is adaptable to Title 22 regulations.
Since the District will recharge the groundwater basin with treated water from the new water reclamation facility, all customers will benefit from the additional water supply and protection of existing water supplies.
The initial environmental review for this project identified potential impacts to aesthetics, air quality, geology and soils, hazardous materials and wastes, hydrology and water quality, land use and planning, noise, transportation and traffic, utilities and service systems. However, specific mitigation measures are being developed to avoid or significantly reduce the potential impacts of the project. These mitigation measures include changes in facility design and implementation of detailed traffic management plans.
The initial study found that the project will not significantly impact agricultural resources, biological resources, cultural resources, mineral resources, population and housing or public services and recreation.
On August 5, 2009 the Board of Directors adopted the Mitigated Negative Declaration and Mitigation, Monitoring and Reporting Program (MMRP). Click here for information on the environmental review process.
Project construction and timeline
The project will be constructed in multiple phases. The current priority, Phase 1, will include the downtown portion of Yucca Valley, which has been identified as the most critical portion of the project due to its proximity to the aquifers and District wells. Phase 1 will include commercial and high density residential customers. In Phase 1, the District will build the treatment and reclamation facility and collection system to treat up to 2 million gallons per day, serving almost 10,000 people.
Subsequent phases will include residential customers and will likely begin once the first phase is complete. The future capacity of the Wastewater Treatment and Water Reclamation Facility will ultimately treat up to 6 million gallons of water per day.
The District is considered a disadvantaged community with a median income lower than the State and National averages. It is critical that the District seek grants and other low cost financing to fund this project. The District is working on a finance plan that will outline the best alternatives to fund the project.
As the District seeks to minimize financial impacts on the community, it is investigating bonds, grants, low-interest loans and other financing methods. Potential funding sources include the Bureau of Reclamation, State of California Bond Funds, Community Development Block Grants, Redevelopment Agency Funds and State Revolving Funds. Costs not covered by grants will likely be financed over 30 years to lessen the immediate impact on the community and provide that future residents and businesses pay their fair share of the cost.
The District can finance the private property connection under the same terms as the assessment (30 years at 0-3% interest).
The District is committed to informing and working with the community. As part of this effort, the Board of Directors formed a citizens advisory group call the Public Advisory Committee. They serve as a community voice in the development and planning of the project. Also, a committee made of community members advised the District on selecting the 80 acre site that the District currently owns for the treatment facility.
The District also seeks to inform the entire community through regular bill inserts, press releases, workshops, project open houses, speaking engagements, the District website and community forums.
The public is encouraged to contact District staff directly for information.
The wastewater treatment plant property is 80 acres east of Home Depot on Highway 62 between La Contenta Road and Avalon Avenue. The wastewater treatment plant will be located on the far south-eastside of the property and will not be visible from the highway.
The preliminary map of the Phases has been adopted. It was designed to address the most critical section of the community, along the highway, nearest the wells. Click here for a copy of the Preliminary Phasing Map.
How to stay involved?
The public is invited to attend the Regular Board Meetings, which are held the first and third Wednesday of each month at 6:00 p.m. in the District board room.
The public is invited to attend the Public Advisory Committee meetings on the second Monday of each month at 5 p.m. in the District board room.
The District will also provide regular communication through bill inserts, newsletters, the website, via email, at open houses and public forums, etc.
If you would like additional information or have any questions, please contact the wastewater information line at (760) 861-8031 or email firstname.lastname@example.org.