Table 1

Summary of Stressors and impacts for salmon and steelhead in Dry Creek

Life Stage Function

adult migration

spawning

incubation and emergence

Juvenile rearing

juvenile migration

Functional requirement

Stressors

Negative impact

sufficient flow

depressed groundwater, lack of flow from effluent sources, change in PCWA flows

inability to reach spawning area

decrease in usable riffle area

drying of redds, insufficient transfer of nutrients and waste, unhealthy temperature

unhealthy temp, increased predation

no migration barriers

diversion dams, utility crossings, bridge sills, excessive sediment, unscreened diversions

inability to reach spawning area, increased poaching at barriers

prespawning mortality

increased predation at barriers, stranding

Channel Complexity:

instream-cobble, boulders, undercut banks, pools riparian-large woody debris, streamside vegetation, good channel morphology

sedimentation from in channel and upland erosion, flood control maintenance, homeowner maintenance, grazing, poor stormwater management

lack of optimal velocity through a range of flows, lack of resting pools

lack of clean spawning gravel

poor percolation for nutrients and waste, inability to emerge from gravel, scouring of redds

increased predation, less than optimal food supply from instream and terestrial sources, less than optimal velocity for growth

appropriate temperature

inadequate vegetation, lack of substrate complexity, inadequate flow, impoundments, effluent

mortality

decreased vigor, size and increased mortalilty

good water quality

poor stormwater management, homeowner maintenance, industrial discharge

poor development, increased mortality