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<br />.:l ':. <br /> <br />-2- <br /> <br />e. The last boat chute below the Union Avenue weir is eroding (NW 3). <br /> <br />f. The bank along the right side of last boat chute below the Union Avenue <br />weir is eroding (NW 13). <br /> <br />g. The erosion control structure at STA 381 +20, which failed in 1994, has <br />still not been repaired (NW 3). <br /> <br />h. The rip rap on the right bank between STA 385+00 and STA 388+00 is <br />eroding (NW 3). <br /> <br />i. The 52" culvert at STA 388+50 is plugged. <br /> <br />j. The second 24" culvert below the rock drop structure at ST A 397 +00 is <br />plugged. <br /> <br />k. The third and fourth 24" culverts below the rock drop structure at STA <br />397 +00 need to have willows cleaned from around the outlets and aprons. <br /> <br />k. The Brown Ditch weir should be checked for sedimentation. It may be <br />necessary to dredge the storage pool to return it to its original storage capacity <br />of 4.7 acre feet (NW 18). <br /> <br />The removal of trees, willows, and other vegetation does not require authorization <br />from my office under Section 404 of the Clean Water Act. For other activities, such as <br />sediment removal and bank stabilization, I have included the Nationwide Permit number at <br />the end of each sentence that could be used to authorize such work under Section 404. For <br />Nationwide Permit number 18, however, there are two cubic yardage limitations (below 10 <br />and between 10 and 25 cubic yards) that require different permitting procedures. In order <br />for my office to authorize work under this permit, we would need to know the cubic yardage <br />of sediment to be removed. <br /> <br />The Nationwide Permits that were issued on December 13, 1996, include a new <br />permit, Nationwide Permit number 31, Maintenance of Existing Flood Control Structures <br />(copy of fact sheet enclosed). This permit would allow the Corps of Engineers to authorize <br />maintenance of the entire project under one permit. However, in order for this permit to be <br />used a maintenance baseline needs to be established, which would be the as-built condition of <br />the project. It is my recommendation that the Colorado Water Conservation Board, working ) <br />with the Urban Drainage and Flood Control District, submit an application to my office <br />requesting establishment of a maintenance baseline and authorization to maintain the project <br />at the baseline level. <br />