2021-02-08_PERMIT FILE - M2021009 (10)

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3653760 STATE OF COLORADO aF Coto BOARD OF EXAMINERS OF WATER WELL CONSTRUCTION AND PUMP INSTALLATION CONTRACTORS i� 490 Division of Water Resources H-` o rr: 1313 Sherman Street,Room 818 Denver,CO 80203 Phone(303)866-3581 FAX(303)866-3589 RECEIVE 0 John W.Hickenlooper Governor http://www.water.state.co.us/boe APR ly p`d 6° 2012 Mike King 1 �t Executive Director,DNR March 13, 2012 vw �o-' Scott Cuthbertson,P.E. v�� Secretary James R. Ford Public Works Department P.O. Box 68 Black Hawk, CO 80422 RE: Request for Variance to Minimum Disinfection Standards (Rule 15) for a Gallery-Type Well, Permit No. 287498, SE '/4 of the NE '/ of Section 32, Township 3 North, Range 72 West, Sixth P.M., Clear Creek County. Request No: 2012-016A Mr. Ford, A request for a variance to the disinfection standards of the Water Well Construction Rules (2 CCR 402-10) was submitted on March 9, 2012 to the Division of Water Resources office in association with Water Well Permit Number 287498. The request has been reviewed by the Board of Examiners of Water Well Construction and Pump Installation Contractors. Specifically, the request asks for a variance to Rule 15, Minimum Disinfection Standards, for several reasons: • The well under this permit is an infiltration gallery well (Hidden Valley Water Treatment Plant Infiltration Gallery) constructed within the alluvium of Clear Creek and three feet below the streambed. It is technically a ground water diversion, but functions similarly to a surface water diversion for municipal water supply. • Water from the gallery well is pre-chlorinated as it enters the Hidden Valley Water Treatment Plant. • The water is again post-chlorinated for disinfection as it leaves the water treatment plant for distribution to the municipal system. • Surface water contamination by chlorine may occur if the standard in Rules 15.2 through and including 15.5 are implemented. Pursuant to Rule 18 and the authority granted by the Board, a variance to Rule 15 and to associated Rule 10.7 is approved. The rationale given above indicates disinfection of water will take place during water treatment plant operation preserving public health. The variance will also ensure that potential chlorine contamination of surface- and shallow ground-water will not occur. Please reference this variance by its Request Number in the space provided for disinfection information on the Well Construction and Test Report and Pump Installation and Test Report to be submitted for the well.