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years to fully develop the herbaceous component of the wetlands. Once that herbaceous component develops it appears to have a high capability of maintaining itself. Where sand encroachment occurs, either by migration of sand downstream or deposition from the side, the wetland tends to decline in vigor. But it also appears that where these rich herbaceous wetlands are large, the perimeter vegetation effectively filters out much of the sand and thereby protects the rest of the wetland. Eventually, it is assumed, all of these wetlands will be overcome by sand, but the more wetland that is present as a result of sand removal the longer these wetlands will be able to sustain themselves. Thus the filtering action of these dense herbaceous wetlands reduces sediment discharge downstream. It also appears that these wetlands serve another valuable function. They tend to store large amounts of water and keep it in the ground. That is these wetlands may actually improve the stability of the water table in the surrounding alluvium. In the "natural" condition where several feet of sand rests on top of the clay layer, runoff probably flows through the sand quite readily and thereby leaves the area quickly before it can sink into the ground. With the sand removed though, dense vegetation growing in the underlying clay slows the water flow and allows more of it to sink into the ground. On the downside, though, removal of the sand also lowers the water table somewhat and thereby causes moisture stress in existing riparian forest. One aspect that also becomes evident when the recovered wetlands outside the enclosures and inside the enclosures are compared is the abundance of woody vegetation inside the enclosures. Cottonwood and willow are both found outside the enclosures, but their development is often stopped by the cattle eating the young plants. Many of these plants clearly show evidence of having been browsed and some are mere remnants of plants that once had their crowns almost completely removed. In contrast, in the mitigation enclosures woody vegetation readily develops and achieves a size that does not allow distinguishing between natural regrowth and planted whips of both willow and cottonwood. Of course, as expected, only a few of these woody plants survive to a point where they can produce flowers and begin to reproduce, but that is an entirely normal development pattern in all vegetation -only the best adapted survive. The point is though, without protection from grazing impacts it is unlikely that riparian forest will develop in any abundance. The mitigation sites clearly show this. Perhaps the greatest value in the mitigation sites is not in the development of wetlands in mined areas but in demonstrating the ability of riparian forest vegetation to develop when grazing is removed. It seems quite clear that the enclosures demonstrate that unless grazing is removed from the riparian areas there is little hope that riparian forest replacement will occur, irrespective of whether the sand is mined or not. The mitigation sites clearly show that the primary factor in replacement of riparian forest is protection from grazing. Mining undoubtedly has some Coal Creek Wetlands and Wetland Mitigation DA Permit 198811488 August 2003 Page 14 of 23