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GENERAL GUIDELINES FOR ~STITUTE WATER SUPPLY PLANS~QR SAND A.. Page 7 of 9 <br />STATE ENGINEER GUIDELINES FOR LINING CRITERIA FOR GRAVEL PITS <br />AUGUST 1999 <br />1.0 Des~n Standard <br />The intent of the reservoir lining design is to achieve ground water inflow (leakage rate) into <br />the reservoir that is not greater than 0.03 ft3/day/ft2 (1x 10-5 cm3/cm2/sec) multiplied by the <br />length of the perimeter wall in feet multiplied by the average vertical depth of the perimeter <br />wall as measured from the ground surface to the pit bottom along the toe of the pit side <br />slope, plus 0.0015 ft3/day/ft2 (5x 10-~ cm3/cm2/sec) multiplied by the area of the bottom of <br />the liner system or natural bedrock bounded by the perimeter wall. Appropriate <br />geotechnical evaluations and analyses should be performed to indicate that the Design <br />Standard could be achieved with the proposed design to a reasonable probability. It is <br />recommended that the applicant submit design and construction plans for review to the <br />State Engineer. <br />2.0 Construction Standards <br />The applicant must demonstrate that the constructed liner meets the requirements of the <br />design by performing appropriate quality control observations and tests. The applicant shall <br />provide written documentation of the work performed and results of quality control field and <br />laboratory tests. Tests performed shall meet or exceed the standards established by the <br />American Petroleum Institute (API) and/or the American Society of Testing and Materials <br />(ASTM) as applicable. <br />3_0 Performance Standards <br />The Performance Standard shall be three times the Design Standard as described above. <br />The Performance Standard shall be applied to an initial test of competency of the liner, as <br />well as to the ongoing operation of the reservoir. <br />3.1 Initial Liner Test <br />For mined pits: The unregulated ground water inflow to the reservoir will be tested by <br />evacuating the contents of the reservoir and observing the inflow of water over a period of <br />ninety days. The start of the test will be under essentially dry conditions. For unmined pits: <br />The unregulated ground water inflow to the reservoir will be evaluated by constructing a <br />dewatering sump at the lowest portion of the pit and then dewatering until asteady-state <br />condition is achieved. Once asteady-state condition exists, the amount of the unregulated <br />ground water inflow will be determined. This process will generally require the installation of <br />piezometers to be located on the inside and outside of the lined pit in the unmined area in <br />order to determine whether asteady-state condition has been achieved. <br />A water balance must be done to demonstrate that the balance of the inflows (e.g., <br />precipitation and ground water) and outflows (e.g., evaporation) equals the change in <br />http://www.waterstate.co.us/pits.htm 10/6/1999 <br />