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u <br /> SIERRA <br /> SES STANDARD OPERATING PROCEDURE <br /> WELL DEVELOPMENT <br /> SES develops ground water monitoring wells not less than.48 hours after placement of the <br /> surface seal(grouting)to allow sufficient time for the cement grout to set The wells are developed <br /> to restore the natural hydraulic conductivity of the formation(s) to be monitored, and to remove <br /> all sand and as much fine-grained material as possible Well development consists of several <br /> cycles of surging (using a vented surge block) and over pumping of the well <br /> Prior to development, SES field personnel measure the depth to water and the total depth <br /> of the well The total depth measurement is compared to the well completion diagram shown on <br /> the field log and any discrepancies are noted <br /> SES begins development by carefully lowering a pre-cleaned stainless steel vented surge <br /> block into the well casing to a position approximately three feet below the top of the well screen <br /> or the air/water interface,whichever is deepest Surging begins with a slow upward stroke motion <br /> of the surge block at a stroke length not exceeding three feet The stroke rate and length is <br /> progressively increased as surging continues for 10 to 15 minutes to loosen sand and fine-grained <br /> material from the screened interval The surge block is then removed and placed in a clean 5- <br /> gallon bucket for future use <br /> During over pumping, the pump is run at the maximum flow rate to evacuate <br /> approximately two well casing volumes of ground water from the well Over pumping will remove <br /> any sediment accumulated in the bottom of the well and any fine-gramed material suspended in <br /> the water <br /> After a cycle of surging and over pumping has been completed SES field personnel record <br /> the time spent on each task, approximate discharge flow rate, and approximate volume of water <br /> evacuated SES field personnel measure the depth to water immediately after pumping and at <br /> various intervals, to approximate the recovery rate of the well <br /> Development shall continue until the turbidity of the water is less than 5 NTUs or when <br /> ten well volumes have been removed whichever occurs first <br />