Laserfiche WebLink
• Minor channel erosion was still evident along a segment of PM-6 above Stock Pond T-32, <br />upstream of the riprapped section (see Photo 3978/GPS Feature #13). Stabilization was <br />recommended, and it was noted that the segment had been marked on the 2008 Rill and Gully <br />Survey Repair Map. In the inspection report dated 10/21/08, the Division noted that this <br />location will be a maintenance issue to be monitored during future inspections. <br />Noxious and problem weeds continue to be present at relatively low levels, with high density <br />patches in some locations (a number of patches were noted during the SL-3 inspection, and <br />several were marked on the GPS map). Weeds that have historically been of concern and <br />continue to be the focus of control efforts at Seneca II include Canada thistle, houndstongue, <br />whitetop, and Dalmation toadflax. Stock pond and sediment pond sites with some additional <br />moisture and disturbance from stock concentrations, as well as locations subject to repeat <br />disturbance for channel or gully repair are where patches of these species are most common, <br />though scattered patches are found even in well vegetated upland parcels. The operator's weed <br />management program appears to have been successful in reducing the densities of these <br />species and minimizing expansion of populations, but continued monitoring and treatment on <br />an annual basis will continue to be necessary. In recent years, annual brome (cheatgrass) <br />appears to have increased in abundance on some reclaimed sites at Seneca 11, and the <br />2007/2008 fall and spring appears to have been very conducive to cheatgrass germination and <br />growth throughout the low to mid elevations zones of northwest Colorado. One patch of high <br />density cheatgrass (approximately 5 acres in extent) was delineated on the GPS map, on the <br />ridge northwest of Stock Pond T-32, between Channel PM-4 and PM-6 (GPS #22/Photo <br />3979). A number of other such patches of similar extent or larger (up to approximately 10 or <br />15 acres) were observed in other locations in the same general area, and various other sites <br />within the bond release request area. Varying densities of perennial species are present in the <br />cheatgrass patches observed. The Division recommends that the operator amend the approved <br />weed control plan to address more aggressive treatment measures for annual brome in areas of <br />significant infestation. The Division considers this issue to be a maintenance item, which will <br />be monitored in the field and reviewed during the upcoming 2009 midterm review. <br />• Rill erosion was not observed along South Road B, although a gully segment with apparent <br />potential for headcut extension was noted immediately adjacent to the road in one location. <br />This was the lower end of the "healed gully" in Photo 3972/GPS #33. On follow-up <br />inspection of 10/16/08 it was noted that the short gully segment had not been repaired, and <br />that maintenance such as riprap installation or rock check installation would appear to be <br />warranted to prevent possible headcutting. The Division considers this item to be a <br />maintenance concern to be checked during future inspection. <br />Surface and Ground Water Pollution Assessment <br />No evident water quality problems were noted during the SL-3 inspection, nor were any such <br />problems noted during the SL-1 inspection or subsequent inspections, with respect to the SL-3 bond