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i~ City of Greeley 24 January 2002 Page 2 STAtiDARDS The SCate Engineer has two standards for reservoir lining design in terms of maximum ai(owabte groundwater inflow from the perimeter and the bottom of the reservoir. These standards are the Design Standard and the Performance standard. The Performance Standard allows for groundwater inEloty three times greater than the Design Standard. These standards ' These standards are used to detecmine the frequency of water budget accounting [hat will need to be implemented during the operation of the water storage reservoir as described in the following [able. After Com lesion of the Initial Liner Test Water Bud e[ Accounting If the Design Standard is mec, btonthly (as long as the liner continues to mac[ i ~ the Desi n Standard} If the Performance Standard is met. Weekly (as tang as the liner continues [o meet the Performance Standard} If the Performance Standard is not met. Every 48 hours. If the Performance Standard ~ is not met for nvo consecutive months, then corrective action sha!! be initiated. s 90-DAY ItiITIAL LIVER TEST The post canstruction testing consists of performing a 90-day Initial Liner Test (Section 3.1}. This test is used to determine the water balance to demonstrate the inflows (precipitation, groundwater} and outflows (discharge from pumping wells). The proposed methad of performing this test is presented below. The proposed liner test involves evacuating water from [he ponds and lowering water table just below the bottom of the pond using dewatering trenches and sumps installed in the bottom of [he ponds. From the seepage rate determined in this scenario, the seepage rate for the gravel pit when completely dewatering can be estimated using seepage calculations (attached}. This test wiif 6e pertormed in the fottawing manner. Fi~~ures 1 & 2 provide the conceptual plan and profile <tf the rest system. ~,.. yr are presented in the table below.