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<br />' to decrease approximately 0.2 feet during mid-winter, ice-covered conditions. <br /> Overall productivity of the winter ecosystem appeared to be maintained by <br /> natural flaws which provided diverse low velocity habitats (embayments, <br />' backwaters, pools, and runs). During winter 2, this diversity appeared to be <br /> best maintained in the 200-300 cfs flaw range in mid-winter during ice cover. <br /> Flaws below this range would result in less than optimum depth in preferred <br /> embayment habitat while higher flows flood and eliminate these habitats. <br /> Alterations in flaw during winter due to water project impacts must be <br /> analyzed with respect to the portion of the winter in which they may o=ur. <br />' Effects will be different due to current ice conditions, air t?mppxatureI <br />precipitation, and discharge. Reductions below natural baseflow at initial <br /> ice formation should be avoided. At this time actual discharge is already <br /> decreasing because water is being tied up in ice formation. Maintaining <br />' natural flaws during the initial freeze period in late November or early <br /> December would insure that ice cover forms over the maximum amount of usable <br /> winger habitat. A key flaw consideration during mid-winter is maintaining the <br /> natural conditions of steady discharge with little fluctuation. Flaws <br />' normally do not flue more than 140 cfs above or below the annual mean <br /> during the period from mid-December through February. It is important to <br /> avoid unnatural discharge fluctuations that could remove natural ice cover. <br />' The ice-out period, which usually occurs in March, can be the most critical <br /> part of winter. During this time, water surface elevations and effective <br /> depth decrease even though discharge is maintained. Therefore, any reductions <br /> in flaw should be avoided until ice is completely out. <br /> <br />1 <br /> <br />t <br />t <br />1 <br /> <br /> <br /> <br />