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After examination of the recovering wetlands (both in the mitigation areas and elsewhere), there is a very consistent, virtually 1:1, relationship between the presence of the clay seam close to the surface and wetland vegetation. Where the clay seam forms the surface the wetland development is consistently the richest and exhibits extremely high cover, excellent species diversity, and high productivity. The clay seam forms a seepage barrier to the ground and surface water, thereby keeping the ground consistently moist. The clay seam is apparently an important growth medium for the wetland species in this area. It is well known that sand does not generally produce a very good growth medium for wetland plants, unless they are completely submerged most of the time. Clays tend to be better, especially for sedges, rushes, cattails, and a number of other common wetland species. At this point, it appears that the mining of the sand overlying this clay seam actually created a condition more favorable to wetland vegetation than was present before the mining. Before the mining it was several feet to the clay seam and the streambed had very little growth because the moisture was spread out over a large depth, the sand was too porous and would not allow the establishment of anoxic conditions, and the water table probably fluctuated drastically during the growing season. Remove the sand and more favorable moisture conditions are created as well as a more favorable growth medium exposed to the surface. The dark side to this observation is that eventually these wetlands will probably be buried again in sand and will slowly decline to a point where Coal Creek will return to mostly a dry, sandy prairie streambed. On the bright side of that, though, this vegetation is very well developed now and it will take either a series of huge thunderstorms in fairly rapid succession, or it will take a very long time for burial to occur. However, if the grazing pressure from these areas can be removed then it is likely these wetlands will develop into even richer, more self- sustaining units and burial with sediment will become even more difficult. Improvement of the adjacent rangeland by reduced grazing would also help to prolong the life of the developing wetlands. Soil loss by primarily sheet and some gully erosion could slowly settle into the wetlands and bury the important clay seam and thereby reduce the wetland growth. Photographs and Maps Included in this report are maps and photographs that provide a thorough record of what was found in the course of this study. These are divided into two sections. The first series of photographs focus on the wetland mitigation sites themselves. These, once again, were taken in 2002 at the peak of the drought. A second series of photographs taken almost one year later show these sites in 2003 after the drought had largely ended. It is interesting that the surrounding hills were brown in 2002 and largely green in 2003, yet the wetlands in the mitigation sites changed very little. This seems to indicate that, at the least, the 100 year Coal Creek Wetlands and Wetland Mitigation DA Permit 198811488 August 2003 Page 7 of 23