1. 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

2. 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

3. Biodiversity matters
Hooper et al. (2005) Ecological Monographs

4. Causal Analysis/Diagnosis Decision Information System (CADDIS)

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

6. 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

8. 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

9. Evaluation of stream habitat

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

11. Comparison of sites in Soos Basin to other regional datasets

12. 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 Scatterplot of high pulse count (HPC) versus PCA axis 1 scores (b). Red circles indicate I sites from the Soos basin.

13. 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 -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 =
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.

14. 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.

15. 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.

16. 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.

18. 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