Table 2 Summary of Hypotheses

Table 2

Summary of Hypotheses

Life Stage Function

adult migration

spawning

incubation and emergence

Juvenile rearing

juvenile migration

Functional requirement

Stressors

Hypotheses

sufficient flow

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

1 Dry Creek watershed is dependant upon surface runoff to attract upstream migrating adults

2 Low flows result in unhealthy temperatures for all life stages.

6 Low flows cause superimposition of redds

Low flows 9 increase mortality and 10 decrease healthy development

17 Low flows increase mortality due to predation

no migration barriers

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

3 Partial barriers in combination with rainfall patterns and other sources of flow influence run timing and geographical distribution sending fish to less suitable habitat, and 4 partial barriers cause prespawning mortality due to poaching

Partial barriers: 18 delay spawning resulting in outmigration during times of unhealthy temperature, 19 provide opportunity for predators. 20 Unscreened diversions increase mortality

Channel Complexity:

Lack of channel complexity causes 11 lack of vigor and increased mortality due to poor percolation, 12 scouring of redds due to increased channel velocity

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

5 Lack of channel complexity causes prespawning mortality due to excess expenditure of energy

7 Lack of channel complexity leads fish to build redds in substrate impacted by sand and 8 to superimposition of redds.

Lack of channel complexity causes 21 increased predation due to lack of cover, 22 decreased food supply due to lack of benthic macroinvertebrate and terrestrial habitat, 23 unfavorable velocities resulting in excess energy expenditure and less that optimal growth.

appropriate temperature

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

13 Dry Creek and Secret Ravine support a non-natal population of juvenile salmon and steelhead. 14 Lack of riparian and channel complexity cause lack of vigor and mortality due to unhealthy temperature.

good water quality

poor stormwater management, homeowner maintenance, industrial discharge

15 Pollutants from urban sources are introduced into the stream and 16 cause poor development and increased mortality

Table 2
Summary of Hypotheses
		Life Stage Function
		adult migration	spawning	incubation and emergence	Juvenile rearing	juvenile migration
Functional requirement	Stressors	Hypotheses
sufficient flow	depressed groundwater, lack of flow from effluent sources, change in PCWA flows	1 Dry Creek watershed is dependant upon surface runoff to attract upstream migrating adults
		2 Low flows result in unhealthy temperatures for all life stages.
			6 Low flows cause superimposition of redds	Low flows 9 increase mortality and 10 decrease healthy development		17 Low flows increase mortality due to predation
no migration barriers	diversion dams, utility crossings, bridge sills, excessive sediment, unscreened diversions	3 Partial barriers in combination with rainfall patterns and other sources of flow influence run timing and geographical distribution sending fish to less suitable habitat, and 4 partial barriers cause prespawning mortality due to poaching				Partial barriers: 18 delay spawning resulting in outmigration during times of unhealthy temperature, 19 provide opportunity for predators. 20 Unscreened diversions increase mortality
Channel Complexity:				Lack of channel complexity causes 11 lack of vigor and increased mortality due to poor percolation, 12 scouring of redds due to increased channel velocity
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	5 Lack of channel complexity causes prespawning mortality due to excess expenditure of energy	7 Lack of channel complexity leads fish to build redds in substrate impacted by sand and 8 to superimposition of redds.		Lack of channel complexity causes 21 increased predation due to lack of cover, 22 decreased food supply due to lack of benthic macroinvertebrate and terrestrial habitat, 23 unfavorable velocities resulting in excess energy expenditure and less that optimal growth.
appropriate temperature	inadequate vegetation, lack of substrate complexity, inadequate flow, impoundments, effluent			13 Dry Creek and Secret Ravine support a non-natal population of juvenile salmon and steelhead. 14 Lack of riparian and channel complexity cause lack of vigor and mortality due to unhealthy temperature.
good water quality	poor stormwater management, homeowner maintenance, industrial discharge			15 Pollutants from urban sources are introduced into the stream and 16 cause poor development and increased mortality