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Revised: 07/26/90 <br />During the 1989 spring runoff season two rills (TR #5 Figure <br />2) formed in the northwest corner of the Bourg property along the <br />east side of the permanent road near the entrance gate (TR #5 <br />Figure 1). Walden Coal Company followed the approved rill and <br />gully plan (page F-12 (a) (revised May 20, 1986) of the Bourg Mine <br />permit) to mitigate the impacts of the erosion An assessment was <br />made of the situation, and appropriate remedial action was taken. <br />The rill and gully plan has since been revised to accommodate the <br />maintenance of a permanent gully (page F-12 (a) (revised July 26, <br />1990) of the Bourg Mine permit). <br />After assessing the drainage pattern of the area it was <br />determined that reshaping the rills into one permanent gully would <br />create the most stable drainage. Zt should be noted that the <br />gully above the culvert had formed naturally prior to Walden Coal <br />Company having any interest in the Bourg property (TR #5 Figure <br />3). Rip-rap was placed in the gully both above and below the <br />culvert in an attempt to ensure the stability of this drainage (TR <br />#5 Figure 4). The gully was also reseeded for additional <br />stability. <br />"Water erosion is one of the most common of geologic <br />phenomena. It accounts in large part for the leveling of our <br />mountains and the development of plains, plateaus, valleys, river <br />flats, and deltas. The vast deposits that now appear as <br />sedimentary rocks originated in this way. This is normal erosion. <br />• It operates slowly, yet inexorably. "Rule 4.14.6(2) was <br />developed in recognition of the fact that gully erosion is a <br />natural geomorphic process in Colorado. " Permanent gullies <br />are an integral part of the natural landscape in North Park. <br />Figure 5 (page I-7 of the Bourg Mine permit) is a map of the Mann <br />Draw watershed. This map delineates a multitude of small <br />drainages or gullies which are an integral part of the watershed. <br />TR #5 Figure 5 is an aerial photo of the Bourg property taken <br />prior to mining. It also shows significant natural rilling and <br />gullying across the property. <br />On July 9, 1990 a survey was conducted of several small <br />gullies in the Mann Draw watershed (TR #5 Figure 6). The purpose <br />of the study was to determine if gully formation is a natural <br />geomorphic process in the Mann Draw watershed as required by the <br />"Mined Land Reclamation Division's Policy on the Management of <br />Rills and Gullies." Walden Coal Company understands that a variety <br />of factors contribute to the formation of gullies. These include <br />but are not limited to: slope aspect and gradient, vegetative <br />community, soils, drainage area, precipitation patterns, and land <br />management practices. An attempt was made to survey gullies which <br />have as many of the same characteristics as the proposed permanent <br />gully as possible. <br />The gullies measured were all lgcated on north to northwest <br />slopes, on gradients of less than 20 in sagebrush vegetation <br />• communities, on the SCS Fluetsch-Tiagos soil series (See TR #5 <br />Table 1). The exact drainage area for each of the gullies was not <br />F-12(b) (1) "~ ~~~zQ~go <br />J 11 <br /> <br />