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<br />MEMORY TRANSMISSION REPORT <br />~J <br />PACE :001 <br />TIME :MAY-16-01 10:21 AM <br />TEL NUA8ER1: +13036663567 <br />NAME :Colorado Division of Minerals 3 Gealaay <br />FILE NUMBER 162 <br />DATE MAY-16 09:55AM <br />TO $3032963601 <br />DOCUMENT PAGES 006 <br />START TIME MAY-16 I0:17AM <br />END TIME MAY-16 10:21 AM <br />SENT PACES 006 <br />STATUS OK <br />FILE NUMBER :162 *** SUCCESSFUL TX NOTICE *** <br />STATE OF COLORADO <br />DIVISION OF MINQRALS ANO GE012lCV ._ _. -.. _ <br />pan.vm..., eI Nu...a R....,.r .. \` <br />111.1 al:arman 5,.. Reem i\ f C <br />~en..r, cviosao eo:m <br />May 17, 2001 <br />Rocky HoHaehneider <br />Plane Sand 8c GraVSI LLC <br />P.O. HOX 180 <br />Lirtleton, CO 60106 <br />PoaPIC Fax Note 7971 aa° / R~~e <br />ty F,v.. <br />m.sa ~. <br />RTia Rvarbaslc asd PIt 9topa wrmorlne propoad, ?aebslcst ReMafoa <br />to 58.8 Min¢ 9¢ctlos 112 Racfsmatlon Parmlt Apptieaeioo, Platte <br />Vatlay 9aad snd Gr+va1, p4v No. M-2000-138 <br />Dear Mr. HoTfschneider, <br />O f <br />M 1 Ns~RA L 5 <br />C E O L O G Y <br /> <br />i .a sG.: no-«e. <br />.r •. ae,.e <br />Plans Sand 8c Oravel LLC has provldetl a technical revision (TRj so further address coneern• wixh erosion <br />potmxial through the gravel pit mining sells during a Inrgv flood event. TM TR includen an illustration of <br />locations the[ the Applicant tans determined to b¢ • with the poteneial for exeessiw aroa[on. The TR <br />includes s Droposel sad dsaigas to aubila'- wrtain oEthe>e potentially s nsitive areas by artnorinS through the <br />placement of tiptop. Ths TR also Includes sons wtima[ea for the placement of riprnp and v dvserlptlon oT xhc <br />timing of tiptop inatW lotion relative so tine sequence o£ vxcnvnlloat lot the gravel piu_ Ths Division's review of the <br />TR is broken out into { w sections in this msmormdum v { ]Iowa: <br />The determination of locations Luc may be sut;ject to erosion during a large flood. <br />The spaeif cession and drawings that will gevsna the a tag and placement of tiptop. <br />a The estimated cost to purohaas and tike delivrry of tiptop that meev apeelflestion, and [o instill rhv riprep is <br />aevoMance with designs and drnwtags approved by the Division. <br />a The timetable for tiptop inatallmion, in particular the insullatien o£the raverbank riprsp. <br />As a r,tmindnr, the purpose of ehe flood eonaoLmltlgatlon plan Is w minimize the poteadnl for excvsalve aoouring <br />mad erosion of pit slopes and oT berms protecting trifled atrueturos such vs gas pipelines, and of offslte Impsea <br />dos m aedimenution or realigmams o£the existing raver chann¢I_ <br />R/prop Locvrlorrs <br />In order to prevent e.<eeaaivs s oaioa, atone that may by subj ass ro snout during s food should be armored. To <br />identify areas oT eeour, rho depth and velocity o£floodwamra should bs ¢stimated snd the gradation of rho coil and <br />subsoil (tend and gravel) mgy be examined along with vegetation eharaercristica to dstmratias if the aroalve power <br />of the flootl will out Iato the vegetation and soil. Plarsmmt of larger and heavier material (tiptop), that •--^aot be <br />Ii Red and m ed by floodwater, will prevrnr erosion mtd down coning in locntlona :dmtifl¢d to be prone to a _ <br />There an a number of published computntionsl methods available to determine rhv nixing and gradation of tiptop <br />regained to vrntor ngninct erosive flows of dill runt velocities. <br />Depth and velocity oT floodwater increassa erapoaentially in flood even of increneingly lower probsbll lty of <br />oecarrenoe. The ems-pmrent an nl thane !food (rhv ailed seat-year flood) R ulT! In s subsutadslly lower <br />flow, depth, and vvlociry than a one-paroent annual chwnce flood (rho 100-year return period avont). Designs for <br />armoring againcr erosion doting a 300-year flood would mort likely fail during o much largo, but longer rsNm <br />