Addendum to Groundwater Extraction Well Number 93 and Appurtenances Initial Study and Mitigated Negative Declaration

Addendum to Groundwater Extraction Well Number 93 and Appurtenances Initial Study and Mitigated Negative Declaration

As part of its local ground water development program and support to its salt and nutrient mitigation plan, Eastern Municipal Water District (Eastern) intends to install up to seven ground water extraction wells in the Perris South, Perris North, and Lakeview/Hemet North Groundwater Management Zones, to generate additional potable water supplies, reduce brackish water migration and remove excess salts and nutrients from the basins. Well Number 93 would consist of 16 to 18-inch diameter well casing extending between 350 to 500-feet below ground surface. It is anticipated that the Well may produce in the order of 500 to 1,500 gallons per minute (gpm) of brackish water. The wellhead facilities may include a well pump foundation, pump, and motor; a building housing electrical and chemical facilities, blowoff pond, discharge pipeline and appurtences. The extraction well site perimeter would be secured by a chain link fence or a block wall as appropriate to the surrounding land use. Subsequent to the publication of the June 2011 IS/MND, the Well has been drilled. Preliminary results from the well development and testing efforts suggest that the well capacity is approximately 2,500 up to 3,000 gpm. Because the production rate is much greater than initially anticipated, an up to 10-acre blow-off pond is required to accommodate the pending two day constant rate well test at up to 3,000 gpm. The proposed pond will be located adjacent to the well site on agricultural land that is currently being cultivated. The property will be returned to the pre-existing condition after the water has percolated or evaporated.

Riverside