BASIN 2000/LYONS CREEK WILDLIFE HABITAT AND TREATMENT WETLANDS DESIGN AND CONSTRUCTION

Wetlands may be created for a variety of purposes including mitigation for necessary wetland impacts, wastewater or storm water treatment, wildlife habitat restoration or enhancement, and/or public recreation. Wetlands can be defined as lands transitional between terrestrial and aquatic systems, where the water table is usually at or near the surface or the land is covered by shallow water. Wetlands provide a number of essential functions and values and are an important ecological component of many landscapes. Although many experts fail to distinguish between the functions and values of wetlands, functions of wetlands provide values usually in reference to human needs. These include food chain support, erosion control, fish and wildlife habitat, flood control, biomass production, low flow augmentation, water quality treatment and protection, aquifer recharge, etc (Kadlec and Knight, 1996).The Lake County Sanitation District (LACOSAN) is developing a program to recycle treated wastewater as part of the Clear Lake Basin 2000 Plan in Lake County, California. This plan includes three primary elements:A recycled water pipeline, approximately 21 miles long, and two pump stations to convey recycled water from the Northwest Wastewater Treatment Plant (NWTP) near the city of Lakeport to wetland sites between the NWTP and the Southeast Regional Wastewater Treatment Plant (SERWTP) near the city of Clearlake.Constructed wetlands to improve water quality, enhance wildlife habitat, offer evapotranspiration of excess water, and provide public benefits by creating settings for passive recreation and wildlife study.Dual recycling through utilization of the “zero-discharge” wetland system and disposal and energy generation for ultimate Geysers reuse for disposal and energy generationThe project elements will be located along the north and east shores of Clear Lake in Lake County, California. Construction will occur in the communities of Nice, Lucerne, Paradise Valley, Glenhaven and Clearlake Oaks. The recycled water pipeline starts at the NWTP and terminates at the SERWTP (See Figure 1 “General Site Location Mapy”). The pump stations are located at the NWTP and the Clearlake Oaks Wastewater Treatment Plant. The new flow control facility is located to the east of the existing NWTP reservoir on the northwest side of Clear Lake. The pump stations and pipeline will be operated to convey recycled water to satisfy water demands at the wetland sites along the pipeline route.Thirty-one potential wetland construction sites were analyzed in a wetland screening study, and each site was ranked according to potential wildlife value and opportunities for cost-effective design and construction. Fourteen of the top-ranked sites were evaluated as part of the preliminary design effort. Two additional sites were included because of their potential for becoming much higher value riparian systems. These 16 sites represent a total of 266 acres, including 110 acres of actual wetland area. A total of nearly 1,000 acres of wetlands could be constructed if all 31 potential sites were developed. A completely developed design product for an initial wetland site at the Lyons Creek site was developed during 1999-2000. The wetland was constructed during the summer of 2000.The focus of this paper will include results from a wetlands screening study, a preliminary design effort and the design and construction of an initial wetland known as the Lyons Creek wetland site.