Stevens Creek Steelhead Limiting Factors Analysis. Stillwater Sciences

Transcription

1 Stevens Creek Steelhead Limiting Factors Analysis Stillwater Sciences May 18, 2004

2 Project Goals! Identify and fill information gaps related to physical and biological factors controlling population dynamics of the focus species! Identify the impact of fine sediment on the focus species relative to other potential limiting factors

3 Analysis Approach life-history based conceptual models processbased conceptual models SYNTHESIZE DEVELOP CONDUCT ANALYZE REFINE DEVELOP existing information initial hypotheses of most likely key factors focused studies limiting factors conceptual models recommendations

4 Stevens Creek Dam built in 1935 Santa Clara Valley Water District website

5 Upstream of Stevens Creek Dam IMG_0285 IMG_0286

6 Downstream of Stevens Creek Dam IMG_0199 IMG_0215

7 Steelhead and Rainbow Trout Lifecycle Stevens Creek SPAWNING Resident UPSTREAM MIGRATION Trout INCUBATION Estuary ESTUARY and OCEAN REARING REARING & Ocean OUTMIGRATION (steelhead only)

8 Watershed with Perennial Reach

9 Urbanized Lower Reaches RM 4.0 Stevens Cr Blvd RM 3.5

10 Changes in Physical Habitat Identify changes in physical habitat to better understand the physical processes that control sediment dynamics in Stevens Creek. Approach: 1.Historical data and review of available information 2.Field reconnaissance

11 Comparison of Stevens Creek channel 1939 and 1999 Stevens Creek RM 4.0 Stevens Creek RM 7.5 Stevens Creek 1939 RM RM 7.0 RM 7.5 RM 4.0 Extent of riparian and floodplain zone from 1939 photograph (above) Extent of riparian and floodplain zone from 1939 photograph (above) 1999 RM RM 7.0

12 Geomorphic Reaches Based on: 1) Floodplain condition 2) Fluvial processes

13 Upper Reach (RM ) Mile ~ 0.3: Source of primarily fine sediment Mile ~ 0.3: Natural bar development, high floodplain function

14 Transitional Reach (RM ) Mile ~ 4.2: Incision greater, concrete structures more prevalent Mile ~ 3.3: Narrower and straighter

15 Middle Reach (RM ) Mile ~ 7.6: Pools shallower, less complex Mile ~ 7.3: Active channel versus historical floodplain Mile ~ 8.2 Incision feet

16 Factors Affecting Channel Equilibrium Slope and Flow Versus Size and Quantity of Sediment Supply Rosgen, 1996, from Lane, The importance of fluvial morphology in hydraulic engineering. Proceedings ASCE, 81(745):1-17.

17 Steelhead and Rainbow Trout Lifecycle Factors Affecting Upstream Migration Attraction flows Physical migration barriers Environmental migration barriers Migration corridor hazards Factors Affecting Estuary and Ocean Rearing Loss of estuarine rearing habitat Water quality and temperature Harvest Ocean conditions Predation Factors Affecting Outmigration Adequate flows for outmigration Water quality and temperature Predation Diversion hazards Estuary & UPSTREAM MIGRATION ESTUARY and OCEAN REARING Ocean Stevens SPAWNING OUTMIGRATION (steelhead only) Creek INCUBATION REARING Resident Trout Factors Affecting Spawning and Incubation Spawning gravel quantity and redd superimposition Spawning gravel quality Water quality and temperature Substrate mobility/scouring Redd dewatering Factors Affecting Juvenile Rearing Availability of summer rearing habitat Availability of overwintering habitat Stranding by low flows Displacement by high flows Predation Food availability Interspecific interactions between native species Competition with introduced species Water quality and temperature Steelhead and resident rainbow trout life cycle and potential limiting factors in the Stevens Creek watershed.

18 Focused Analyses Fish Passage Barriers Gravel Permeability Pool Filling Bed Mobility Overwintering Habitat Water Temperature

19 Population Modeling: (1) Use habitat variables to parameterize stock-production relationships Habitat area Embeddedness Permeability Carrying capacities Fry Adults Parr Fry Smolts Survival/fecundity, etc. Parr

20 Population Modeling: (2) Use stock-production relationships to generate population dynamics Habitat area Embeddedness Permeability Smolts Year Fry Spawners Adults Parr Fry Smolts Fry Smolts Parr Parr

21 Focused Analyses Fish Passage Barriers Gravel Permeability Pool Filling Bed Mobility Overwintering Habitat Water Temperature

22 Fish Passage Barriers Hypothesis: Barriers to upstream and downstream migration limit steelhead production in Stevens Creek. Methods: Review of existing information

23 Fish Barriers IMG_2595.JPG SCVWD HB2i SCVWD HB27 SCVWD HL3

24 Barrier Locations

25 Results Spawning Gravel Area Pool Area Barrier Location 70 Percent (%) Perrenial Reach Distance Downstream of Dam (mi) Cumulative percentage Figure 5-2. Cumulative of spawning percentage gravel of area spawning (ft²) and gravel pool area area (ft²) (ft²) and pool downstream area (ft²) of Stevens Creek downstream Dam (data of Stevens from FAHCE Creek Dam. 2000).

26 Results Fraction of smolt production Barrier Locations Fraction of maximum smolt production Fry Spawners Smolts 0.1 Parr Distance Downstream of Dam (mi) Expected smolt Figure production 5-3. Fraction in the of potential perennial smolt reach production of Stevens in the Creek, perennial based reach on of Stevens amount of available spawning, Creek, based rearing, on amount and overwintering of available spawning, habitat. rearing, and overwintering habitat

27 Spawning Gravel Hypothesis: Spawning gravel quality and quantity limit steelhead production in Stevens Creek. Methods: Field studies and review of existing information

28 Spawning Gravel Site C gravel patch and standpipe IMG_0241 IMG_0290 Site P view of habitat unit (RUN) and standpipe IMG_0270 Site K sample from gravel patch (D50=1.5 )

29 Results 100% 90% 80% McCuddin 1977 (chinook) Tagart 1976 (coho) Fitted model 90% confidence limits 95% confidence limits Survival-to-Emergence 70% 60% 50% 40% 30% 20% 10% Survival = Ln Permeability Adjusted R 2 = 0.85 p < % 100 1,000 10, ,000 Permeability (cm/hr) The egg survival-to-emergence index used to interpret the relative impact of measured permeability on steelhead production is based on the regression derived from data collected by Tagart (1976) for coho salmon and McCuddin (1977) for chinook salmon.

30 Results Area (ft²) Distance Downstream of Dam (mi) Habitat Area Figure (ft²) 5-5. of Habitat spawning Area (ft²) gravel, of spawning summed gravel, over summed 0.1 mi over increments 0.1 mi increments downstream of Stevens Creek downstream Dam of (data Stevens from Creek FAHCE Dam 2000). (data from FAHCE database)

31 Results 1 Fraction of maximum potential smolt production current survival Fry Spawners Parr Smolts Emergence survival value Figure 5-6. The expected results in terms of smolt production, given different levels of emergence survival values (max density = 1.0/m3).

32 Pool Filling Hypothesis: Reduction of juvenile rearing habitat due to pool filling by fine sediment on Stevens Creek is a significant problem given the observed embeddedness and distribution of fine sediments during field reconnaissance in December Methods: Modified V* assessment based on Hilton and Lisle (1993)

33 Results Pool #19 view looking upstream (mile~1.3) Pool #6 view looking upstream (mile~4.5)

34 Bed Mobility Hypothesis: Bed mobility is high in Stevens Creek, which might lead to frequent scour of redds and subsequent mortality of steelhead eggs and alevins. Methods: Field reconnaissance to provide a nonquantitative assessment of bed mobility in Stevens Creek

35 mile ~ 7.5 mile ~ 9.8 Results mile ~ 0.1

36 600 SF44 Daily Average Flow SF35 Daily Average Flow 500 Daily average Flow (cfs) Oct-74 1-Nov-74 1-Dec-74 1-Jan-75 1-Feb-75 1-Mar-75 1-Apr-75 1-May-75 1-Jun-75 1-Jul-75 1-Aug-75 1-Sep-75 Date Daily average flow at Stevens Creek gages SF44 (0.6 miles downstream of Stevens Creek Dam) and SF35 (downstream of Highway 237) for water year 1975 (average annual precipitation).

37 Winter Habitat Hypothesis: Winter habitat quality is limited due to high levels of substrate embeddedness and low abundance of coarse substrate. Methods: Field reconnaissance and use of existing habitat database to provide an assessment of winter habitat in Stevens Creek

38 Winter Habitat Abundance Boulder Area Cobble Area 200 Area (ft²) Distance Downstream of Dam (mi) Stevens Figure Creek cobble Area and in boulder pools with area cobble (sq. or ft.) boulder within substrate all pools, in Stevens summed Creek, over summed 0.1 mi increments over (data 0.1 mi from increments FAHCE (data 2000). from FAHCE 2000).

39 Winter habitat quality 1 Fraction of maximum potential smolt production Fry Spawners Parr Smolts Winter habitat quality (fish/ft²) Figure Expected smolt production as a function of overwintering habitat quality (i.e., fish density).

40 Water Temperature Hypothesis: Water temperatures limit growth and survival of juvenile steelhead in Stevens Creek. Methods: Review of existing information

41 1-Nov-00 1-Nov Water Temperature Water Temperature Daily Maximum Daily Average Daily Minimum 1-Jul-00 1-Aug-00 1-Sep-00 1-Oct-00 Day 1-Jul-00 1-Aug-00 1-Sep-00 1-Oct-00 1-Jun Daily Max Daily Avg Daily Min Mile 0.6 Mile Jun-00 Temperature ( F) Temperature ( F)

42 Water Temperature Steven F. Railsback and Kenneth A. Rose. 1999: Bioenergetics Modeling of Stream Trout Growth: Temperature and Food Consumption Effects. TAFS. 128 :

43 Results Frequency (number of fish) Figure Length f histogram requency Chart for Rainbow Trout at Two Different 2002) and Locations FAHCE Downstream (2000)). of Stevens Creek Dam: McClellan Road Crossing (9/22/1994), and 140 Length (mm) Length frequency histogram of O. mykiss in Stevens Creek (compiled from Leidy (1984;

44 Summary of Findings Barriers limit access to a substantial amount of habitat; effects s on smolt production depend on ability of fish to pass barriers (upstream and downstream) Gravel permeability is low but not likely limiting production Pool filling is low, indicating high sediment transport capacity relative to sediment supply Bed mobility (and therefore redd scour) is relatively low in upper reaches but increases downstream Overwintering habitat is likely the key limiting factor prior to outmigration Water temperature is elevated but not likely limiting production, as evidenced by size of age 0+ and 1+ steelhead