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Irrigation Water BBID would remain as the irrigation water purveyor to the project site. Because BBID's water canals on the College Park site would be filled/removed in the course of project development,BBID and the project applicant are negotiating alternative methods through which BBID can deliver irrigation water on a long-term basis for use at Delta College and the community park. The ultimate methods for continued delivery of irrigation water to the project site would be outlined in a farm irrigation and drainage plan,which would be submitted with the tentative tract map for the proposed project(MacKay&Somps 2004a). r BBID maintains two irrigation canals, canal 120 and canal 155,that cross the project site in a northwest-to- southeast trending direction(see Figure 4.5-1).These irrigation canals supply the existing agricultural operations on the project site as well as agricultural operations downstream and to the southeast of the project site.Further descriptions of these canals are included in Section,4.2,"Land Use and Agriculture."As described above,BBID would need to construct new pipelines to convey irrigation water to Delta College and the community park. In addition,BBID would continue to provide service to the area southeast of the project site. Canal 155 would need to be constructed through the project site to serve the community college and the community park and be connected to the existing canal on the southeast side of Mountain House Parkway.The precise location for the infrastructure would be outlined in a farm irrigation and drainage plan that would be submitted with the tentative ` tract map for the proposed project.However, a preliminary location of the proposed BBID irrigation water line has been identified for the project site,as shown in Figure 4.5-1. Groundwater As discussed above,BBID maintains two irrigation canals that cross the project site which supply agricultural operations.These irrigation canals would be filled or removed through the course of development. Concern was raised about how removal of the two irrigation canals would affect existing groundwater levels in the project study area. As irrigation water flows through the two irrigation canals,a certain portion of water seeps into the ground thereby assisting with recharge of groundwater resources. As a result of this concern, a field reconnaissance of the irrigation canals was conducted by Wallace-Kuhl&Associates on February 5,2005 (Appendix n.During the reconnaissance,the irrigation canals were found to be predominantly dry with some standing water in small areas. The canals were observed to be unlined throughout their lengths and appeared to be well maintained and free of any significant vegetation. Depth to groundwater was measured by two piezometers located adjacent to the canals on April 7 and May 26, 2004. Specifically,piezometer P-2 is located adjacent to canal 155 and piezometer P-3 is located adjacent to canal 120.Piezometer P-2 measured the depth to groundwater at 32.6 feet below the surface on April 7,2004 and on May 26,2004 measured the depth to groundwater at 31.4 feet.Piezometer P-3 measured the depth to groundwater at 32.1 feet below the surface on April 7,2004 and on May 26, 2004 measured the depth to groundwater at 14.5 feet.These depths indicate a 1.2 foot rise and a 17.6 foot rise in groundwater elevation April 7th and May 26th. According to BBID(Flores 2005)the regional use of irrigation water has declined significantly over the past several years. Specifically,water deliveries south of Mountain House Creek for canal 120 dropped from 1,779.36 acre-feet in 2003 to 596.61 acre-feet in 2004.Along with this,deliveries to canal 155 dropped from 764.88 acre- feet in 2003 to 162.17 acre-feet in 2004. Consequently,impacts to groundwater recharge occurring as a result of restricting water to canals 120 and 155 have already occurred for the most part and are reflected in the current groundwater conditions of local wells including Grant Line Village wells. In addition,BBID would be supplying irrigation water to new residential and commercial customers in the project vicinity, including the community college campus. It is anticipated that decline in local groundwater recharge from canals 120 and 155 would be more than offset by recharge from residential and commercial landscape irrigation. College Park at Mountain House Specific Plan III Draft EIR EDAW San Joaquin County 4.5-3 Public Utilities