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r~EC~iU~~ .~~~~ 0 5 ¢C~~ <br />LI~~CH <br />I-IYDROGEOLOGISTS ^ ENGINEERS ^ ENVIRONMENTAL SCIENTISTS <br />June 4, 2009 <br />City. of Elk River <br />Rebecca Haug, Environmental Administrator <br />13065 Orono Parkway <br />,.:• e..: rr~~n <br />EIk River, 1vliIIiiC~U~u. J~:i~+I <br />RE: Knife River Co. (Toth Property) Proposed Gravel Washing Operations <br />Dear Ms Haug: <br />On behalf of the City of Elk River, Liesch Associates, Inc. (Liesch) has reviewed the proposed <br />gravel washing operations for the Knife River operation located on the Ernest Toth property within <br />the Elk River Gravel Mining District. The proposed. gravel washing .operations. requires a <br />Minnesota Department of Natural Resources Water Apprapriations Permit for.which an application <br />has been submitted by the applicant. It is understood that washing operations will utilize water <br />from areas that have been excavated below the water table and that washing is expected to be <br />seasonal and intermittent depending on market demand. The pumping rate is estimated at 250 gpm <br />with an annual volume of up to one-million gallons. <br />Liesch recommends that the following tasks be considered with respect to the proposed gravel <br />washing operation: <br />• Identify and/or confirm the location of nearby groundwater wells (groundwater receptors) and <br />surface water receptors on and immediately surrounding the mining and gravel washing <br />operation and document their proximity to the washing operations on a map. <br />• Install a water table monitoring well or wells at the Site and generally between the washing <br />operation and the nearby groundwater receptor(s). Survey the monitoring well(s) for horizontal <br />and vertical control and identify their location on a Site map. <br />• Measure and record water elevations at the monitoring well(s) within approximately one-week <br />of 'initiating pumping of water from the dug pit for- washing, mid-way during washing and <br />within one-week upon cessation of washing operations. <br />• Conduct water quality • testing of samples collected' from .monitoring .:.well(s) for diesel range <br />organics (DRO), BETX, pH (field), temperature (field) acid specific conductance (field) prior to <br />and at the cessation of washing operations on an annual basis. <br />www.liesch.com <br />LIESCH ASSOCIATES, INC. ^ 13400 15TH AVENUE NORTH ^ MINNEAPOLIS, MN 55441 ^ 7631489-3100 ^ FAX: 763/489-3 I O I <br />