1997-06-05_REVISION - M1981302 - Laserfiche WebLink

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Memo to File M-81-302 -7- June 5 . 1997 ISSUE #2 Floodplain Implications The Land Berm Quotes pertinent to the City of Boulder' s concerns in this regard, from the letter dated 4/22/97 : . . .the City of Boulder requests that the DMG require Western Mobile to submit additional detailed information about the land berm and relevant impacts on the surrounding community prior to any final determinations concerning the proposed reclamation plan amendment for the Deepe Farm Pit . The City of Boulder understands that the Flatiron Companies, Western Mobile, and the University of Colorado propose to include the subject land berm in site reclamation for the Deepe Farm Pit as a flood protection barrier against the adverse flooding impacts the gravel mine has created for lands downstream of this mining site. Neither has Western Mobile provided a detailed technical evaluation of the land berm in the context of final reclamation for the mining site. This includes the absence of any analysis regarding changes in floodplain conditions in the area due to mining activity, the heightened flooding risks for surrounding neighborhoods, and other site reclamation alternatives that Western Mobile considered which would not require a flood protection barrier. The perimeter levee proposal for the Deepe Farm Pit has been withdrawn from consideration under the pending amendment application, and is now the subject of a technical revision to the Deepe Farm Pit permit . As part of the review process for the technical revision application, the Division has requested additional information from the operator on the floodplain impacts of the proposed levee compared to the floodplain impacts based on the previously approved reclamation topography. The Division will use the requested additional information to make a determination as to whether or not the proposed levee will result in damage to adjoining property, and as to whether or not the proposed levee serves to effectively minimize disturbances to the prevailing hydrologic balance of the affected land and of the surrounding aro4a. Based on a preliminary review of the available flood hazard studies for the reach of South Boulder Creek in the vicinity of the Deepe Farm Pit, it appears that the developed areas north and northwest of the pit would incur a greatly increased flood hazard if the levee is removed than exists with the levee in place.