Document - Green River Recreation Instream Flow Study
AbstractWhitewater flow preferences were identified for four watercraft types on four reaches of the Green River. The flow preferences include minimum acceptable flows, optimum flows and high challenge flows for each watercraft and reach. The flow preferences vary by watercraft and whitewater reach. Overall, minimum acceptable flows ranged from 600 cfs in the Headworks reach for canoes to 1400 cfs for catarafts and rafts in the Upper Gorge. Optimum flows ranged from 900 cfs for kayaks in the Headworks reach to 3000 cfs for catarafts and rafts linking three reaches into a single outing; the Headworks through the Lower Gorge. Boaters using catarafts and rafts typically link more than one reach into a single outing. The whitewater challenges and aesthetics in the Upper Gorge were the primary attraction for most boaters on the Green even when multiple reaches were linked into a single outing. Minimum acceptable flow preferences for the Upper Gorge ranged from 1100 to 1400 cfs for all watercraft types. The optimum flows for the Upper Gorge ranged from 1400 to 3500 cfs. Enhancement of whitewater boating opportunities on the Green can be made through improved flow information, scheduled whitewater flows coordinated with annual project operations and short term shaping of outflows to target whitewater opportunities. These opportunities exist during the fall drawdown period, winter flood control operations and the spring refill period. Inclusion of short and long term forecasts will greatly improve flow predictability for the boating community. The flow information should include greater transparency regarding HHD management objectives both short and long term throughout the year as well as fisheries management objectives. The whitewater flow preferences identified in this study demonstrate substantial overlap with the seasonal flows recommended for anadromous fish. Whitewater flows, applied within the appropriate seasonal timeframe, appear quite compatible with the anadromous fishery.
Filename - Green River Recreation Instream Flow Study617.pdf
Size - 1.84MB
2 - Green River Gorge III-IV
Green River (WA)
AW works with partners to protect flows and the scenic landscape of the Green River Gorge.