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Infrastructure Services Wastewater Treatment Objective 1 "To ensure adequate wastewater treatment and the safe disposal of liquid waste." The response from Public Health Services states that they cannot support the proposed percolation ponds at this site, as public health and safety would be compromised. Hydroloov The site is adjacent to the San Joaquin River. The application materials state that groundwater is generally 15 to 16 feet deep over most of the site. However, groundwater levels are still comparatively low and will gradually rise as the area recovers from the recent six-year drought. Public Health Services has noted that in 1983 and 1986, there was sidewall and toe seepage along the levees in this immediate area and that groundwater has 'boiled up" on the site during extremely wet years. The Soil Conservation Service has identified the soil type on the site as Grangeville fine sandy loam. This type of soil may provide wetland functions and values and, in areas adjacent to levees, is subject to lateral seepage in wet years when the water table is high. Given the soil type and characteristics, high groundwater table, and proximity to the San Joaquin River, there is the potential for significant impacts to ground and surface water quality. Because of the high water table and soil type, the ponds may fail under wet conditions. There is also the potential for levee failure and subsequent flooding of the site, with impacts to surface water quality. During recent years, this has occurred to wastewater treatment facilities in Santa Rosa and Guerneville. The Environmental Health Division also noted that portions of this site were flooded during the 1980's. The City of Manteca also noted that one of the reasons Lathrop was included in the grant for the Manteca Phase I Wastewater Treatment Plant Expansion Project was that the plant in Lathrop did not work properly because the percolation ponds did not provide adequate disposal of the effluent. According to the City of Manteca, the water did not percolate as quickly as necessary because of high underground water levels caused by clay layers in the soil strata. The clay layers stopped the water from percolating and created a perched water table relatively close to the ground surface. Biological Resources The 62-acre site has been used in recent years for the production of oat hay, which provides foraging habitat for Swainson's hawks nesting nearby along the San Joaquin River. Development as proposed will eliminate approximately half of the site's foraging habitat. A biological assessment was prepared by the city's consultant, who recommends on-site mitigation - specifically,the creation of habitat on the remaining half of the site not developed with percolation ponds. The Department of Fish and Game has reviewed the biological assessment and suggested mitigation and has concurred that on-site mitigation may be acceptable, provided that it is consistent with the 1:1 ratio specified in the Department of Fish and Game's Draft Mitigation Guidelines for Swainson's Hawks. As a point of reference, the City of Lathrop, the applicants for the project, are currently subject to a court stipulated judgement regarding the Swainson's hawk as a result of a successful legal challenge to the city's recently adopted General Plan. This judgement stipulates that until the city adopts a Habitat Conservation Plan (HCP) or participates in a regional HCP, the city cannot annex additional areas. San Joaquin County SA-93-42/Crossroads Ventures Community Development Page 7