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2000 1800 1600 1400 -- ~ 1200 ~ ;3: 1000 0 ~ E t<l 800 ~ tl en 600 400 Natural Flow Hydrograph ___ Conventional Dynamic Instream Flow Water Right '.~~lM 200 0 -0 '" 0 '" 0 .q- 0-. <"'l 00 .q- 0-. <'"I --- .::::: r<'l - r<'l .::::: <"'l .::::: ~ .::::: ~ .::::: !:::! 0 23 ...... " --- :;p - 0 - C"'l N - - C"'l N <"l <"'l - - - - oor<'lOOC"'lr-Nr---oOV) ~::::~~~-..~~~__C:! .q- l~ '" ~ ~ r- r- 00 00 0-. 0-. FIGURE 3. Conventional Dynamic Instream Flow Water Right This proposal defined four flow values and each flow value defined the instream right depending on the actual streamflow. The first two flow values, a subsistence flow and a biological maintenance flow, were related to the low flows of winter and early spring and were based on the survival needs of fish and aquatic insects. The third flow value was the average annual flow. The fourth flow value was the flow with a return period of 1.5 years, which closely approximates the flow level needed to reach the top of the active channel. The third and fourth flow values were based on the needs of both riparian vegetation and aquatic species. The instream flow water right, according to the proposal, would protect a dynamic flow; as long as the actual flow was less than the biological maintenance flow, the subsistence flow must be met. The biological maintenance flow must be met as long as the actual flow was above the biological maintenance flow and less than the average flow. When the actual flow was between the average flow and the 1.5-year flow, a percentage of the streamflow would be claimed. When the actual flow was above the 1.5-year flow, the actual flow of the stream would be protected. This last component is an upside-down way of protecting instream flows, making this proposal a hybrid. This dynamic flow water right would still allow for some development of upstream water resources, yet would presumably protect the variable flows that the USFS and the CWCB agreed were associated with a wilderness area.3 3 Once submitted to the CWCB, this proposal met with stiff resistance and was never adopted, possibly because it resembled the claim for channel maintenance flows being asserted by the USFS as a federally reserved water right elsewhere in Colorado. Congress then side-stepped the issue of water right protection for such downstream wilderness areas in Colorado by not designating the Piedra and three other downstream areas as wilderness in the bill that was passed in 1993, and directing only that these three areas be managed to maintain their wilderness character for potential wilderness designation at a later time (Gillilan and Brown 1997: 294). The Nature Conservancy and the USFS have also since purchased and retired the one big, water development right upstream of the proposed wilderness area on the Piedra River. 6