2009-07-15_REPORT - M1988044 (2)

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that cottonwood would be stronger here, but that does not seem to be the case. It its also important to note that the large area east of the exclosure that was previously mined is showin;; a similar development pattern. With the removal of grazing both willow and cottonwood has shown strong expansion, even into areas where they were previously rare to nonexistent. The removal of grazing has greatly benefitted the reclamation of the south lowland area. The channel relocation area continues to show excellent development and without any heavy flows since the changes were made, it has had an opportunity to establish a great deal of stability. It, as well as the south lowland, could still be negatively affected by a heavy flow, but the impact will be much less significant now that the growth has developed at least a moderately robust density. Exclosure 2 seems to be the one that is showing the slowest development as its water supply is somewhat limited. But even here, gains are significant with both willow and cottonwood making excellent progress. Exclosure 4 continues to show excellent gains in the lines of cottonwood established along old stream banks, but there has been very little increase in the number of plants. In some places, small cottonwoods continue to arrive but seem only marginally able to compete with the dense herbaceous growth of wetland species surrounding them. The general stream channel in this area has developed a strong growth of cottonwood and willow. This is a major shift in composition from what it was before grazing was removed. At that time the area was dominated by beaten and damaged willows and grossly distorted cottonwoods that had been affected by browsing during the winter months. Now, the cottonwoods are growing rapidly and in some places dominate the willows, but in other places the willows have established an almost impenetrable wall of vegetation in the stream bed. Further to the south of the mining areas and in Section 36, significant increases in stream channel growth have occurred since the removal of grazing. Although far less dramatic than what has occurred to the north, it is not surprising that heavy flows on Coal Creek have become less and less common, even with very large storms. One of the important functions of woody as well as herbaceous growth along intermittent prairie streams such as Coal Creek is to control peak flows and reduce flood damage. At this point, it appears this function is being achieved to a fairly high level. That is not to say that huge, damaging floods could not occur, but with the attenuation of peak flows caused by good stream channel vegetation, it will take still larger storms to create a damaging flood. It is also more than likely that the removal of grazing has allowed uplands to recover to such a degree that runoff into the stream channel has been greatly reduced and that, in turn, affects the intensity of peak flows that cause damage to the stream corridor. As has been shown many times before, one of the best techniques for improving the condition of a stream channel is to improve the uplands that feed into the stream channel. The removal of grazing has allowed that improvement to occur and that is being reflected in the great improvements in the condition of the stream channel. Thus, by improving the upland growth the entire system, upland and lowland, is stabilized so the previous flooding is greatly reduced to the point where it takes a very large storm to generate a flood whereas floods were previously generated with fairly small storms. Ecologists and hydrologists have said that in all likelihood, the huge damaging floods seen in the 20`h century were rare events prior to the introduction of poorly managed grazing that threw the prairie systems out of balance and allowed frequent flooding and the choking of stream channels with sand that only increases the intensity of peak flows. At this time, it appears that this entire system on Coal Creek in this area is moving back toward that pre-grazing condition where floods are fairly rare events. Status report for 2009 due July 15, 2009 Page 6 of 10