Sandy,
Regarding your inquiry about the summer low flows and diversion return flows in Cascade Creek I can offer this basic information:

The summer low flows are already so low that my predecessor agencies (Departments of Fisheries and Wildlife) recommended that no new diversions from Cascade Creek be allowed.  Fish presence, including spawning, has been well documented by both biologists and residents.  Reducing the summer flows will reduce the available fish habitat and cause undo stress to what may be San Juan County's only salmon bearing stream.

Return flow from the diversion ditch has been observed to be a significant contributor to the flow in Cascade Creek downstream of the two diversion dams in Moran State Park.  On June 7, 2005 I estimated about 4 cfs coming out of the Mountain Lake Dam and observed just a bare trickle of water over the Rosario Utilities Dam.  On that same day, with the Rosario Utilities diversion ditch running freely, I measured 1.25 cfs above the waterfall near Buck Bay.  The evidence is strong enough to warrant further study and to be very cautious when making changes that might reduce or eliminate flows when they are most needed by fish.

Steve Boessow, Water Rights Biologist
Department of Fish & Wildlife
Habitat Program
(360) 902-2410 voice
(360) 902-2946 FAX
boesssnb@dfw.wa.gov