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<br />Lavvr;a.ce S&H Letter <br />Page :>. <br />the NPDES permit. Such S&H discharges shall not impair or degrade Western <br />Mutual's future TMDL's that may result from future NPDES regulations. 1 <br />cannot evaluate the impacts from S&H's de-watering discharges since there is <br />insufficient detail in the application for me to base a technical opwon. <br />2. The proposed mining plan does not provide any detailed information with respect to <br />monthly free water surface evaporation and resulting river depletions. Western Mutual <br />owns numerous senior and junior water rights up-stream and doHn-stream of the S&H <br />mine which tray be injured by such depletions. By S&H's own admission, no water rights <br />are owned by the mine corporation. Western Mutual should require the DMG to add a <br />condition to the permit which otily allows for tnining after S&H obtains ownership of an <br />augmentation source. S&H has made statements that an Substitute Supply Plan (SSP) <br />will be approved by the State Engineer shortly. This SSP includes a short term effluent <br />lease from the City of Longmont. This supply is not guaranteed and thus should not be <br />allowed by the DMG or the State Engineer. S&H should be requved to file for a <br />permanent plan for augmentation in Division I Water Court. Western Mutual should insist <br />that a Water Court approved augmentation plan be provided prior to the commencement <br />ofany mining operation and the exposure ofalluvial ground water. This is the standard <br />that Western Mutual and all other water users must comply. I noted that DMG did not <br />include a bond requirement for S&H to ensure that if evaporative depletions are not <br />augmented by S&H, then S&H must fill in all azeas of exposed water surface. This is a <br />standard requtrement placed on other gravel operators. <br />S&H identified irrigation returns that have historically been received by the South Platte <br />River in this location via a small ditch. However, S&H does not state how such returns be <br />re-routed to the river as a result of its proposed mining. <br />4. DMG raised the issue of flood control and offsite impacts related to flooding. S&H states <br />that Pickett Engineering has been retained to review this issue. I cannot provide any <br />technical comments with regazds to the proposed flood control measures that will be <br />proposed by Pickett Engineering until I review the report. However, S&H proposes to <br />armor the east bank of the South Platte River if mining occurs within 150 feet of the river <br />bank. S&H does not present any detail as to the nature of material, easement acquisition. <br />[n addition, such armoring will require a U.S. Army Corps permit and also may require <br />Federal Emergency Management Agency (FEMA) backwater analysis to ensure the <br />adjoining land owners do not experience increased innundation due to flooding. <br />5. The proposed mining plan does not provide detail regarding air and noise quality and <br />mitigation. These should be a condition put in the DMG and County permits. <br />LEAFENGINEERING <br />Hydrology ~ Hydraulics ~ WaterResources ~ Water Quality <br />[::LLeafl'lre:lem MutualLLawrence Weuern Mutual Injury Lcltcr.Mpl <br />