The proposed groundwater production well field is located approximately one mile south of the Yuba River, within the Yuba Groundwater Basin. This groundwater basin is composed primarily of alluvial deposits, specifically the Laguna and Older Alluvium Formations, both of which are capable of delivering large quantities of groundwater to wells. To evaluate the potential impacts of the well field operation on surrounding groundwater levels, a finite-element groundwater flow model of the area was constructed. This model was calibrated to several aquifer tests performed in the vicinity of the Goldfields, and provides reliable estimates of groundwater impacts due to groundwater pumping from the aquifers in the area.

Simulations performed using this modeling tool suggest that peak groundwater declines that would result from operation of the well field would be less than three feet at a distance of one mile from the well field. A water level decline of three feet is well within the range of seasonal groundwater fluctuations that occur in the basin, and does not even approach the historic low groundwater levels that occurred in the basin in the early 1980s, prior to the expansion of surface water delivery capabilities for irrigation. Therefore, this change in groundwater levels is not expected to have any substantial effect on the productivity of wells in the area or pumping costs.

At distances significantly greater than one mile from the well field, such as at the town of Gold Village, changes in groundwater levels due to the proposed well field operations will likely be undetectable. Wells screened in the bedrock aquifer located in the foothills east of the proposed well field draw water from local bedrock fracture systems that are not related to the alluvial aquifer of the Yuba Groundwater Basin. Therefore, it is not expected that pumping from the alluvial aquifer will have any significant effect on wells screened the in bedrock.

Additionally, Alan B. Lilly of Bartkiewicz, Kronick & Shanahan, acting on behalf of the Yuba County Water Agency (YCWA), provided a letter to the SWRCB dated September 30, 2005 concluding that the “groundwater [supply in question] will be presumed to be percolating groundwater, for which no water-right permit is required.” This letter is attached to this technical memorandum as Attachment 4.

Yuba Highlands will construct its own water and wastewater plants on site. Wastewater will be used to water golf courses and parks and as a result of the re-use of waste water Yuba Highlands total water use at its build-out will be less than the water required to irrigate a 1,700 acre rice farm.