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Dec-04-O1 02:23P <br />.r ~.a <br />..r~lo.~ <br />December 4, 2001 <br />Lidstone and Associates. Inc. <br />P_02 <br />Irxgixeering Can/c~(ry ~ Wrrteslfetrarrrce Contirr/rarrar <br />Jeffrey W. Schwarz <br />Massey, Semenoff; Schwan 8t Bailey <br />Hudson's Ray Centre <br />1600 Stotrl Street <br />Suite 1700 <br />Denver, CO 80202 <br />Rc: DMG Request for Additional Information Mobile Yremix Concrete, loc., Howe Pit (Permit <br />M-7&052) <br />Dear Mr. Schwarz: <br />At your request, 1 have reviewed the State of Colonldu, Divisinnl of Mines and Geology letter of <br />November 21, 2001. Brian Wood and 1 met with Tom Schreiner, Allen Sorensrnt, and Carl Mount rnt <br />Friday, November 30, 2001 artd presenled the requested modeling results. During this meeting we <br />discussed the major issues associated with our forensic analysis of the May 5, 2001 bank failure and <br />presenled our professional opinion that the bank failure and resultant downsh•earn damage was nut related <br />to existing location of the Bull Seep. <br />With this letter and enclosures, Lidstone and Associates, Tne. (LA) responds to the State of Colorado <br />Division of Mines and Geoluty (DMG) letter of November 21, 2001 (Schreiner to Hickman). '!'ern <br />Scllreirlcr's original letter outliltcd six points. I am addressing Points 2, 3 and possibly 4. <br />Paint 2 <br />It is my untlerstandirlg that the original flood control ICVCe was constnteted as a WPA levee sometime in <br />tltc lato 193Us or 1940x. Following the construction of the Brantrtcr Diversion Strucrure, tht fanners <br />adjacent to the area shed the Branttter Diversion Ditch Company, alleging that the Diversion caused flood <br />damage to their prnpcrry. Some of the Flood scars from a 1949 event Can be seal on the torte 21, 1950 <br />photo (see Figun; 2.1). 1 nssume that the 1949 flooding and the fanners' concerns led to additional <br />conslrtrction and/or extension oCthe WPA flood control levee in a ttortltward direction. <br />i have previously submitted the 1950 aerial photograph in a digital manner to Allen Sorensrnl. A review <br />of the Jllne 1950 aerial photograph suggests the pn:scnce of n ditch/swalc along the inboard side of the <br />levee. My assumption is that the individuals who constructed the levee, borrowed "fill" n]aterial from tlfe <br />inboard side of tltc Icvice. The photo doesn't suggest any other nearby burrow areas. This phuW indicates <br />that the levee extension was under construction as of the daft of This photo (6/21/1950). One can sec <br />what appears to be a tlow line and setlimentatiolt near the tlownstream terminus of this structure. This <br />same area is now referred to as the "intersection of the Butt Seep Drain and Bull Seep Slough". <br />This feature is also documented in the pre-disturbance mapping of the area as shown in Mobile Premix <br />Concrerc Permit (M-78-052). Please reference tltc Drainage Plan Map (Sheets 1 and 2). Thcsc sheets are <br />X023 Aumm+rion W.y, awlding L•'. Fort Colliro. Colorado BOS23-]44A 713 L. Kspecvell. Kivvcon, Wywnmg 82301-]662 <br />(970)22]4703 TM: (97U1223g706 r.mail: walerCatlidSr6ne.~rom (3071 8363271 fax: (707) X36.3261 o-mail: rivenon r(Alidsrone.cum <br />