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TABLE 27 Sediment Balance of Reduced,Depleted, and Redistributed Peak Flows (100,000 acre-feet/year target depletion) ---------- Percent ------------- Mean Annual --------------------- Annual Sediment Load ---------------- , Million Tons -------------- Years Balance Remaining Flow, cfs Deerlodge Park Mathers Hole --------- Set to Zero -------------- ---------- 90% ------------- 2014 --------------------- 2.361 ------- 2.501 31 80% 2002 2.234 2.293 18 75% 2000 2.182 2.205 6 72% 1999 2.154 2.156 3 71% ---------- 1999 ------------- 2.145 --------------------- 2.141 --------------- 0 ---------------- Again, as the daily flow pattern changes such that the peaks are reduced, depleted and then redistributed to baseflow, the days in which the balance is set to zero declines. Only the high flow years of 1983-1986 are able to effectively reduce the balance as peaks are reduced further and further. Total transport at Mathers Hole is again greater than at Deerlodge Park, but as the flow distribution changes and is depleted, the balance is not set to zero as often and the loads at both locations approach being approximately equal. Sediment Balances of Reduced, Peaks (No Redistribution) When the peak flow months of April through June were reduced by various percentages but not redistributed to the power generation months of July- September and December-March, the peaks could be reduced the furthest from historic levels and still maintain a balance through the reach. This is because the baseflow months in general tend to accumulate sediment and the peaks move it out. Without increasing the baseflows, less peaks were required to maintain a balance. Tables 28 through 32 show the running balances for retaining 900, 80%, 70%, 65%, and 64% of the daily flow values, respectively. Mean annual discharges change in volume and in monthly distribution in this scenario also, since the reductions are essentially depletions. Table 33 summarizes the budgets shown in Tables 28 through 32.