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<br />To: Larry Ohler <br />From: Berhan Keffelev~ <br />~~~ <br />" <br />Subject: llllll <br />~~~ <br />M-79-011 ~~~ <br />Date: December 15, 1999 <br />Re: M-97-01 I TR# I BERM DESIGN AND CAPACITY. <br />MEMORANDUM <br />As you requested, I have e~raluated the design submitted by the Barnhart Agency on behalf <br />of the operator. The designed earthen dam will be 6' by 9' crest width and 18' wide 3: I <br />side slopes on each side of the dam. Since this is a temporary dam, all the operator was <br />required was, to design a structure to retain the 10 year 24 hour event before it is <br />discharged .The dam was identified as a storm water management design, which is <br />regulated by CDOH & E, which only requires a 2 year event, the dam as will be <br />constructed as submitted in the TR will be more than adequate to Handle the flow. The 10 <br />hear 24 hour event for the area is 2.5 inches, a total watershed of 40 acres with a Curve <br />Number of 70 was used to calculate the maximum discharge. I contacted Mr. Buck <br />Bamahart the consultant and he assured me that a before ,during and after construction <br />pictures will be provided to the Division, to verify that the dam was constructed as <br />submitted in the TR .The main purpose of this dam is to limit the amount of sediment from <br />the disturbed area from reaching the natural drainage east of the pit floor, it should be <br />more than adequate to handle the flow. <br />NOTE: The MAP submitted with the TR was not to scale. There is also NO EFFLUENT <br />STANDARDS UNDER THE CLEAN WATER ACT FOR STORM WATER DISCHARGE. <br />CC: James Stevens <br />iii iiiiiiiiiiiuiii <br />^ <br />