Laserfiche WebLink
iii <br />To: Larry Ohler gg <br />From: Berhan Keffelew o1 <br /> <br />Subject: Hydro Review, M-1999-005 <br />Date: March 13, 2001 <br /> <br />MEMORANDUM <br />As you requested, I have evaluated the operators proposal to pump water from the pit area <br />so mining can take place. You wanted to know, if there would be impacts to the shallow <br />ground water wells in close proximity to the pit . In particular, you wanted to know possible <br />impacts to two shallow wells located North of the area where pumping will take place. These <br />wells one at 43 feet deep with static water elevation at 19 feet and the other at 39 feet deep <br />and static water at 13 feet deep yield between 900 to 1000 g.p.m. Both of these wells are <br />with in the 25 year 24 hour flood plain of the Arkansas river. The operator is proposing to <br />install a 3000gpm pump that is regulated by a ground water level detection sensor. The pump <br />only operates, when the water level rises above the sensor. On March 8, 2001, the site was <br />inspected with the operator present. Operator has obtained a discharge permit from CDPS, <br />and was pumping and discharging to the Arkansas River from the lined pond that was <br />constructed for the process, at the time of the inspection. During the inspection, static water <br />near or at the surface was noted in portions of the permit area from the floods of two years <br />ago. According to the operator, because of the clay formation, located approximately 4 to 8 <br />feet below the surface in the permit area, the flood waters of two years ago, did not percolate <br />to allow economical mining, hence the need to pump the water . In order to create a cone of <br />depression to affect wells in the are, the rate of pumping has to exceed the rate of recharge. <br />The water being pumped from the pit area is going back to the river. During the permitting <br />process, the Division had evaluated possible impacts to wells in the area from the operation. <br />Even during dry years, there was a negligible fluctuations to the static water levels in the area. <br />At that time, the Division evaluated all the permitted wells in the area and concluded the <br />impacts to wells to be negligible. That opinion is still valid for this review. <br />cc: James Stevens <br />^ <br />