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• iii iiii iiiniu iii • <br />999 <br />,,,o.; gym,, Lidstone and Associates. Inc. <br />~.c~ava r< <br />Eru~ineerirrg Geo~ogrJ & water Xesou~ee Cansu~Iants <br />December 4, 2001 <br />^r n^4'~ <br />3`d._.i ~. _ . ~' <br />r~~ ~ "i <br />Jeffrey W. Schwarz <br />Massey, Semenoff, Schwarz & Bailey <br />Hudson's Bay Centre <br />1600 Stout Street <br />Suite 1700 <br />Denver, CO 80202 <br />]ieision of Yunetah a~:u Geology <br />Re: DMG Request for Additional Information Mobile Premix Concrete, Inc., Howe Pit (Permit <br />M-78-052) <br />Dear Mr. Schwarz: <br />At your request, 1 have reviewed the State of Colorado. Division of Mines and Geology letter of <br />November 21, 2001. Brian Wood and I met with Tom Schreiner, Allen Sorenson, and Carl Mount on <br />Friday, November 30. 2001 and presented 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 />presented our professional opinion that the bank failure and resultant downstream damage was not related <br />[o existing location of the Bull Seep. <br />With this letter and enclosures, Lidstone and Associates, [nc. (LA) responds to the State of Colorado <br />Division of Mines and Geology (DMG) letter of November 21, 2001 (Schreiner to Hickman). Tom <br />Schreiner's original letter outlined six points. I am addressing Points 2, 3 and possibly 4. <br />Point 2 <br />It is my understanding that the original flood control levee was constructed as a WPA levee sometime in <br />the late 1930s or 1940s. Following the construction of the Brantner Diversion Structure, the farmers <br />adjacent to the area sued [he Brantner Diversion Ditch Company, alleging that [he Diversion caused flood <br />damage to their property. Some of the Flood scars from a 1949 event can be seen on the June 21, 1950 <br />photo (see Figure 2.1). 1 assume that [he 1949 flooding and the farmers' concerns led [o additional <br />construction and/or extension of the WPA flood control levee in a northward direction. <br />I have previously submitted the 190 aerial photograph in a digital manner to Allen Sorenson. A review <br />of the June 1950 aerial photograph suggests the presence of a ditch/swale along the inboard side of the <br />levee. My assumption is that the individuals who constructed the levee, borrowed "fill" material from the <br />inboard side of [he levee. The photo doesn't suggest any other nearby borrow areas. This photo indicates <br />that the levee extension was under construction as of the date of this photo (6/2l/19~0). One can see <br />what appears to be a Flow line and sedimentation near the downstream terminus of this structure. This <br />same area is now referred to as the "intersection of the Bull 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 />Concrete Permit (M-78-0~2). Please reference the Drainage Plan Map (Sheets I and 2). These sheets are <br />4025 Automation Way, Bwlding E. Fort Collins, Coloredo 80525-3148 715 E. RaosevelC Riverton, Wyoming 82501-3662 <br />f970) 223705 fax: (970) 227-1706 c-mail: water(allidstone.com (307) 856-5271 fax: (307) 856-5281 a-mail: rivrnonna lidstone.com <br />