Laserfiche WebLink
:~ <br /> <br />Pao FLOOOc <br />~, o <br />~ ~ <br />Q p <br />? O <br />a r- <br />60 ~O <br />bean 1~\ay <br />Board of Directors <br />Executive Comminee: <br />Cathy Reynolds <br />Chairman <br />Cary of Denver o <br />Linda Morton ° <br />Charman Pro-Tem p <br />City of Lakewood '~ <br />Harald Kite > <br />Sacrelary ~ <br />Adams County ° <br />John Stone • <br />Treasurer ~ <br />Jeflersan County <br />'a <br />Donald Hamstra r <br />Member n <br />City of Brighton 3 <br />0 <br />Memoers: N <br />Bruce Alexander m <br />Cary of Denver N <br />Nadine Caldwell w <br />City of Aurora <br />N <br />Ruben A. Chnstensen , <br />Douglas County o <br />David A. Day a <br />Engmaer N <br />Joyce Foster R <br />City of Denver ~ <br />Sanoy Hume ° <br />Boulder County <br />John J. Nicnoll <br />Arapahoe County ~ <br />Deborah Ortega <br />City of Denver <br />Art Patton o <br />Engineer i <br />Mary Poe "~' <br />Town of Mornson = <br />Dennis Reynolos <br />City of ~nleton <br />Michael J. Romero <br />City of Lalayene <br />Mr. Rick Mergens <br />Vice PresidendGeneral Manager <br />Cooley Gravel Company <br />Post Office Buz 5485 <br />Denver, CO 80217 <br />Subject: Dahlia North Resources Pit <br />MLRB 112 Permit Application <br />City of Commerce City, County of Adams, Colorado <br />Dear Rick: <br />~II ~I~II~~I~I~~~II~ <br />RECEIVES <br />DEC p 719 <br />Division of Minerals & Geolo9Y <br />We have reviewed the subject application with respect to the South Platte River <br />Technical Review Guidelines for Gravel Mining Activities Within or Adjacent to 100- <br />year Floodplains. We have the following concerns: <br />1. Your consultant has measured the 100-foot minimum setback from a different <br />location than what the Urban Drainage and Flood Control District requires for <br />the "Master Plan with Riverbank and Pitside Protection" option to be used. <br />The consultant measured the distance from the edge of the existing low flow <br />channel, whereas the gravel mining review criteria requires that the distance be <br />measured from the edge of the proposed master plan channel alignment or from <br />the top edge of river channel, whichever is greater. These limits have much <br />less impact on your land than the original published master plan lines. <br />L. $COt1 Tucker, Executive Director <br />Recently the District and Cooley agreed to riverbank protection along the <br />revised master plan alignment as shown on the attached map. The 100-foot <br />setback should be measured from this proposed river bank protection (agreement <br />of October 27, 1994) and not from the existing channel bank as shown on <br />Exhibit C-2. The only other item that needs to be addressed is a spillway to <br />qualify for the 100-foot setback. <br />2. No reference is made to a side channel spillway. Typically if the riverside berm <br />is longer than 1,300 feet, two side channel spillways are required. However, <br />due to the channel and bank geometry adjacent to this project, only one side <br />channel spillway will be needed near the downstream end of the berm. See <br />Section 2.4.5 of the Gtavel Mining Guidelines to size spillway. We estimate a <br />spillway length of 480 feet based on a final water surface area of 132 acres. In <br />addition, the river side and pitside slopes of the spillway must be protected with <br />very large rock. The crest of the spillway should not exceed the 5-year flood <br /> <br />December 5, 1994 <br />~, <br />-u' <br />