1. 1 SacEFT: Bank swallow model Sacramento River Ecological Flows Tool Refinements Workshop Expanding & Communicating Ecological Considerations Used to Evaluate Water Management Alternatives October 7, 2008 Katherine Wieckowski

2. 2 The system context: multi-year resolution Multivariate – species, life history stages, units Need to integrate, aggregate and compare with a simple common palette There must be credible models under the hood Experts may need to drill down to years, days, locations

3. 3 The system context: annual resolution Rules for assigning colour breaks differ for daily and annual scales and are sometimes complicated WY1974 – wet year WY1977 – critically dry year

4. 4 The system context: daily resolution When present, daily color (R/Y/G) depends on distribution of historical daily results across all locations All examples show a Good and Poor year

5. 5 Habitat requirements Nesting habitat: Nests burrows built in steeply sloped banks in friable soils Immediately adjacent to still or running water Banks renewed every few years by erosive processes

6. 6 Bank swallow (BSW) indicators Two indicator models chosen through 2005 workshop Models share common structure but different parameters Models are habitat- based, not population- based*

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8. 8 Selected functional relationships

9. 9 BSW indicators BSW1 – Length of newly eroded banks with suitable soil texture (m) BSW2 – Indicator of bank sloughing (i.e., collapse) during nesting (Red/Yellow/Green hazard zones)

10. 10 BSW indicators: temporal context Generalized phenology of bank swallow life history stages for birds breed in the Sacramento Valley, California Stillwater Sciences (2007)

11. 11 Representative hydrograph from pre-Shasta period relative to bank swallow life history stages. Stillwater Sciences (2007)

12. 12 BSW indicators: spatial context KeswickRM 301 Red BluffRM 243 Colusa RM 143 light green – area captured by BSW1 (area most relevant for bank swallow biology) dark green – areas captured by BSW2

13. 13 BSW indicators: spatial context RM201 RM185 River segment 2

14. 14 BSW1– Length of newly eroded bank 1. L depends on meander migration rate (W) and area of floodplain reworked (A) 2. Meander migration model solves for W and A 3. L calculated annually for each modeled bend 4. Scoring of annual results is based on terciles of total length taken from historical run with no bank revetment 5. L is insensitive to flow

15. 15 BSW1 – Length of newly eroded bank 1. Calculate L for each bend (b): 3. Weighted useable L b for each segment (l): 2. Weight or each bend (b): 0 when (L < 13m) w b when (13m ≤ L ≤ 20m) 1 when (L ≥ 20m) 4. Calculate BSW1 for the river :

16. 16 BSW1- Length of newly eroded bank

17. 17 BSW1: Why insensitive to flow? Low inter-annual variability in W Scale mismatch between meander migration model and length scale used for weighting. Narrow range of variation in terciles generated from historical data L doesn’t account well for depth of bank erosion Stillwater Sciences (2007)

18. 18 BSW2 – Peak flow during nesting 1. Calculated daily by location (3 locations) using flow (Q) 2. Based on flow thresholds (20 kCFS and 50 kCFS) 3. Timing of flows effects impact 4. Scoring of daily and annual results is heuristic 5. Somewhat insensitive to flow

19. 19 BSW2 – Peak flow during nesting If 2 or more locations are good, BSW2 R is assigned good Lower ratings are assigned as poorer site performance is observed (e.g., if 2 or more locations are bad, BSW2 R is assigned bad) 1 when (Q < 20kCFS) BSW2=when (20kCFS ≤ Q ≤ 50kCFS) 0 when (Q ≥ 50kCFS) 1. Calculate BSW2 for each location: 2. Calculate annual BSW2 R for the river

20. 20 1974 – wet year1977 – critically dry year BSW2

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