Technology 2005: 2nd Joint Specialty Conference for Sustainable Management of Water Quality Systems for the 21st Century: Big Bear Area Regional Wastewater Agency (BBARWA) Water Purification Project
Abstract:The Big Bear Area Regional Wastewater Agency (BBARWA) along with its member agencies are working together to address the current and future problems arising from lack of sufficient water resources in the region by implementing a water purification project. The BBARWA service area is located in the Big Bear Valley, a resort community surrounded by the San Bernardino Mountains. The primary water supply in the area is groundwater although use of lake water for snowmaking is permitted at the area's two ski resorts. Because local water resources are limited, and the population and associated water demand continue to increase, the area faces a water supply availability and reliability problem. Other contributing factors to the problem are (1) downstream communities including the City of Redlands owning the water rights for the water in Big Bear Lake and (2) imported water from the State Water Project and/or the Colorado River Aqueduct is not available and connecting to this source would be cost prohibitive and would not increase water supply reliability during droughts. As a result, the Big Bear Valley relies almost entirely on the groundwater systems in the area, which are fed through localized rain and snowmelt, for water supply. These factors exacerbate the effects of periodic droughts by drawing down groundwater levels. For this reason, the area is in need of other water sources that will augment and provide a drought-proof, reliable, and locally-controlled water supply.
Purified water from the BBARWA's Regional Wastewater Treatment Plant (WWTP) has been identified as a potential supplemental water supply in the area. Currently, the average daily flow treated by the BBARWA WWTP is about two million gallons per day, which is discharged to a 480-acre disposal site in the Lucerne Valley where it is used to irrigate alfalfa. Although the WWTP effluent is being used productively, it is a water resource that could be reused within the Big Bear Valley. Currently, the BBARWA does utilize a small portion of the treatment plant effluent, approximately 11 acre-feet per year (afy), for irrigation, construction compaction and dust control, and wildlands fire fighting.
Demand for water in the Big Bear Valley periodically exceeds supply, particularly in dry years or during prolonged drought periods. Currently, the area is experiencing its sixth year of drought. The BBARWA, along with the Big Bear City Community Services District (BBCCSD), and City of Big Bear Lake, Department of Water and Power (DWP), are working collectively to address this drought as well as prepare for future droughts. One component of the plan is to dramatically boost the production of recycled water and reuse it within the Valley. The proposed water purification project will include upgrades to the WWTP, extension of the recycled water distribution system, and supply to urban irrigation user locations and artificial surface groundwater recharge sites. Implementation of the recharge project would provide the BBARWA with a beneficial use for recycled water within the water's basin of origin and utilize the existing natural storage capacity that has been depleted through groundwater extraction.
The proposed work will be divided into three phases: preliminary studies, design, and construction start-up. The preliminary studies are currently underway and consist of groundwater recharge pilot testing, environmental assessment, evaluating wastewater treatment plant process upgrades, and analyzing brine management alternatives. The design and construction phases will include the required infrastructure and the staged implementation of artificial groundwater recharge, with an initial diversion of 500 acre-feet per year (afy) followed by incremental increases of 500 afy up to a total of 2,000 afy. The design is scheduled to begin in 2005 with the project online by 2008.
For long range planning purposes and better coordination of BBARWA's reclamation efforts, a recycled water master plan was initiated that outlines the project's components, technological alternatives, and program costs. The master plan is scheduled to be completed in late 2004. The first step in the master plan was a preliminary market assessment to identify the optimal users of recycled water. The optimal recycled water users were determined based on a ranking system which used the annual demand of the user, constructability of a distribution pipeline, and the willingness of the user to receive recycled water as criteria. After identifying potential users and conducting a demand analysis, pipeline alternatives were identified, and a hydraulic model was developed for the recycled water system to evaluate system facility needs. The treatment system was also analyzed to determine the most reliable alternative treatment approaches. This information was used to develop a cost analysis for the distribution system and treatment alternatives. In addition, a preliminary Capital Improvement Plan was developed which includes phasing, water/wastewater cost sharing, and financial impacts of the project on recycled water users.
Another component of the preliminary work was to perform a geohydrologic study. The geohydrologic evaluation included preliminary reconnaissance and identification of multiple sites for further investigation, site access and environmental assessment, preliminary investigations and borehole drilling, investigation of regulatory requirements, and pilot testing of the groundwater recharge sites. The investigation process narrowed the list of candidates to two potential recharge sites, the Green Spot and the Van Dusen sites. Surface recharge pilot tests were used to assess percolation rates of recharge water, impacts of recharge on groundwater levels, and migration characteristics of the stored water. The preliminary artificial recharge rates measured from the pilot recharge test were approximately 3.1 ft/day for Green Spot and approximately 1.1 ft/day for Van Dusen.
The preliminary studies of the BBARWA project have identified that the BBARWA WWTP will require upgrades to produce water for reuse based on Title 22 requirements. Title 22 of the State Code identifies, provides, and outlines the treatment requirements for recycled water by use type. The BBARWA must obtain permits from the Santa Ana Region RWQCB and approval from the California Department of Health Services (CDHS) to use the recycled water for urban irrigation and groundwater recharge. Permitting and approval from these agencies will require a sub-scale pilot test program that demonstrates the effectiveness of the proposed advanced treatment system on the BBARWA effluent. The BBARWA plans to perform pilot testing in 2005. The proposed BBARWA WWTP upgrades include addition of advanced treatment processes which are comprised of microfiltration (MF) and reverse osmosis (RO) along with ultraviolet (UV) disinfection. The proposed upgrades to the BBARWA WWTP will exceed RWQCB and CDHS requirements for urban irrigation and groundwater recharge. In addition to WWTP upgrades, a brine handling facility will also be required for the treatment of brine generated at the MF/RO facility. This facility is necessary to reduce the volume of the brine/concentrate, thus reducing some of the hauling costs off the mountain.
The purpose of the BBARWA water purification project is to reuse, to the extent practicable, water within its basin of origin. The project will augment water supply in the region by increasing the long-term reliability and availability of groundwater in the region and provide a drought-proof, reliable, and locally-controlled water supply.
Document Type: Research Article
Publication date: January 1, 2005
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