Chad Larson - WDOE Daniel Marshalonis - EPA Region 10 Flow pulses and fine sediments degrade stream macroinvertebrate communities in King County, Washington, USA Chad Larson - WDOE Daniel Marshalonis - EPA Region 10

Freshwater systems under threat Vörösmarty et al. (2010) Nature Freshwater systems comprise only a fraction of the total water found on the planet, yet supply nearly two-thirds of the water used in the world

Biodiversity matters Hooper et al. (2005) Ecological Monographs

Causal Analysis/Diagnosis Decision Information System (CADDIS)

Soossette Big Soos Little Soos Covington Jenkins King County, near Covington, WA 26 sites in this region with data

King County, near Covington, WA 09SOO1106 09SOO1144 09SOO1209 09SOO1283 09JEN1318 09JEN1357 09JEN1358 King County, near Covington, WA 7 sites with Category 5 listings for biological impairment based on B-IBI

Evaluation of biological response variable (B-IBI) (12) (150) (64) 25 30 35 40 R N I B-IBI (10-50) Evaluation of biological response variable (B-IBI) Soos – not impaired reference Soos –impaired (10) (11) (9) (7) 10 15 20 25 30 35 A B C D E F G B-IBI (10-50) Figure 3. Average B-IBI scores for R sites versus N and I sites from the Soos basin (a). Average B-IBI scores for the seven I sites from the Soos basin (b). Sample sizes shown in parentheses. Soo1106 Soo1144 Soo1209 Soo1283 Jen1318 Jen1357 Jen1358

Evaluation of stream habitat

Evaluation of habitat at impaired sites in Soos Basin Jen1318 Jen1357 Jen1358

Comparison of sites in Soos Basin to other regional datasets

Flow metrics in the Soos Basin -4 -2 2 -1 1 3 4 PCA axis 1 (61.7%) PCA axis 2 (14.5%) WY mean Q TQmean R.B. Index HPC HPD HPR LPC LPD Flow Reversals -4 -2 2 10 15 20 PCA axis 1 scores High pulse count (HPC) r = 0.95 Supplementary Figure 1. Principal component analysis of hydrological flow metrics with percent of variance explained by each axis in parentheses (a). Definitions of the various flow metrics are in DeGasperi et al. 2009. Scatterplot of high pulse count (HPC) versus PCA axis 1 scores (b). Red circles indicate I sites from the Soos basin.

Linking biological response with high pulse count (HPC) Relative importance of variables in multiple regression 5 10 15 20 25 30 35 High Pulse Count B-IBI (10-50) R 2 = 0.587 p 0.00013 -5 5 HPC given other variables B-IBI (10-50) given other variables HPC IC Area Method LMG 20 40 60 80 Method Last Method First % of R 2 Method Pratt R2 = 70.49 %, metrics are normalized to sum 100% -0.10 -0.05 0.00 0.05 0.10 -4 -2 2 4 6 Impervious Cover % given other variables B-IBI (10-50) given other variables -500 500 1000 1500 2000 -6 -4 -2 2 4 6 Area given other variables B-IBI (10-50) given other variables HPC IC Area 0.267 -0.014 0.106 0.297 -0.009 0.019 -0.019 Residuals = 0.354 Figure 4. Average B-IBI scores versus average HPC for each modeled region in the Soos Creek basin (a). Red circles indicate I sites from the Soos basin. Added variable plots for B-IBI versus HPC, given other variables (percent impervious cover and area) in a multiple regression model (b), B-IBI versus percent impervious cover, given HPC and area in the model (c), and B-IBI versus area, given HPC and percent impervious cover in the model (d). Summary statistics for simple linear and multiple regression in the text.

Linking biological response with elevated fine sediment (12) (150) (64) 50 100 150 R N I Fine Sediment Biotic Index (10) (11) (9) (7) 20 40 60 A B C D E F G Fine Sediment Biotic Index Soo1106 Soo1144 Soo1209 Soo1283 Jen1318 Jen1357 Jen1358 (12) (150) (64) 10 20 30 40 50 R N I % fines (inferred) (10) (11) (9) (7) 25 50 75 100 A B C D E F G % fines (inferred) Figure 5. Average FSBI scores for R sites versus N and I sites from the Soos basin (a). Average FSBI scores for the seven I sites from the Soos basin (b). Average inferred percent fines for R sites versus N and I sites from the Soos basin (c). Average inferred percent fines for the seven I sites from the Soos basin (d). Sample sizes shown in parentheses.

Evaluating organic pollution & low DO & elevated metals (12) (150) (64) 3.0 3.5 4.0 4.5 5.0 R N I Hilsenhoff Biotic Index (10) (11) (9) (7) 3 4 5 6 A B C D E F G Hilsenhoff Biotic Index Soo1106 Soo1144 Soo1209 Soo1283 Jen1318 Jen1357 Jen1358 (12) (150) (64) 1.0 1.5 2.0 2.5 R N I Metals Tolerance Index (10) (11) (9) (7) 0.0 0.5 1.0 1.5 2.0 A B C D E F G Metals Tolerance Index Figure 6. Average HBI scores for R sites versus N and I sites from the Soos basin (a). Average HBI scores for the seven I sites from the Soos basin (b). Average MTI scores for R sites versus N and I sites from the Soos basin (c). Average MTI scores for the seven I sites from the Soos basin (d). Sample sizes shown in parentheses.

Evaluating temperature (12) (150) (64) 5 10 15 20 R N I Cold Stenotherm Richness (10) (11) (9) (7) 0.0 2.5 5.0 7.5 10.0 12.5 A B C D E F G Cold Stenotherm Richness Soo1106 Soo1144 Soo1209 Soo1283 Jen1318 Jen1357 Jen1358 (12) (150) (64) 12.0 12.5 13.0 13.5 14.0 R N I Temperature °C (inferred) (10) (11) (9) (7) 10 12 14 A B C D E F G Temperature °C (inferred) Figure 7. Average inferred water temperature for R sites versus N and I sites from the Soos basin (a). Average inferred water temperature for the seven I sites from the Soos basin (b). Sample sizes shown in parentheses.

Summary Used existing data to conduct a stressor identification employing CADDIS Use of biological, chemical, and physical habitat metrics provided a holistic evaluation Eliminated several potential stressors as the most likely cause of biological impairment Biological impairment linked with flashy flow (HPC), elevated fine sediment and habitat Template for conducting other stressor identifications in WA