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1/7/2016 <br />State.co.us Executive Branch Mail - Re: Sediment <br />STATE, OF Hernandez - DNR Alysha <alysha-hernandez@state-co-us> <br />� �OL,O R�'AI O ' <br />Re: Sediment <br />1 message <br />Zuber - DNR, Rob <rob.zuber@state.co.us> Thu, Jan 7, 2016 at 7:31 AM <br />To: "W D Corley, Jr." <ajjc@att.net>, Al Weaver <alweaverefci@gmail.com>, Alysha Hernandez - DNR <br /><alysha.hernandez@state.co.us>, Jim Stark - DNR <Jim.Stark@state.co.us> <br />Alysha, please file this Southfield correspondence with Dr. Corley in Laserfiche and name it "Sediment loading <br />into Pond 5." <br />Dr. Corley - It is my professional opinion that the RUSLE model is not at all accurate in predicting the quantity <br />of sediment that leaves a given area. It is a useful tool for comparing sediment loading from one area to <br />another area. <br />As for the erosion in the roadside ditch, the Division anticipates that this will be a point of discussion between <br />EFCI and yourself. Please advise if I am incorrect about this point. <br />Regards, <br />Rob <br />Rob b ...; P.E. <br />Coal RegulatoryProgram <br />r <br />Departrnent of Nal.ural 1iesources <br />303.866.3567, extension 8113 1 F 303.832.8106 <br />1313 Sherman Street, Room 215, Denver, CO 80203 <br />rob.zuber@state.co.us I http:Urnining.state.co.us <br />On Wed, Jan 6, 2016 at 8:02 PM, W D Corley, Jr. <ajjc@att.net> wrote: <br />Rob, <br />For a more objective way to determine the amount of sediment leaving the Southfield portal disturbed area, <br />have repeated a topo survey of Pond 5. Then I compared the current sediment levels in this pond with a topo <br />survey performed in 2011. The additional sediment in the pond in 4.4 years is 200 cu. yds. or 300 tons using <br />the conversion of 3000 Ib. per cu. yd. I believe that the sediment in the pond was dozed to the south end in <br />2011 and possibly cleared away from the inlet culverts a second time since 2011. It should be noted that the <br />sediment now is higher than the flow line of the south culvert. Comparing the amount of sediment deposited <br />in Pond 5 averaging 68 ton per year since 2011 to the RUSLE model prediction in the bond release application <br />of 0.313 ton per acre per year or 44.2 ton per year for 141.27 combined portal reclaimed acres, there is <br />measurably, by a factor of about 50%, more sediment leaving the disturbed area than the model <br />prediction. The likely source for this excess sediment is probably from the north side of the road cut for the <br />RDA haul road. There are very large walls of both alluvium and shale that show extensive erosion. These <br />walls have slopes of over 150% grades. The storm water runoff leaves in the north side road ditch and reports <br />to Pond 5 through the south inlet culvert. <br />Doug Corley <br />https://mail.googl e.com/m ai I/u/0/?ui=2&i k=e29129fcb5&view=pt&search= i nbox&th=1521 c8O38e01f3a5&si m l=1521 c8O38e01 f3a5 1/2 <br />