1. U.S. Department of the Interior U.S. Geological Survey Idaho District Office (208)387-1323 ahrea@usgs.gov Estimating Hydropower Potential Using EDNA Stage 1B Data: Arkansas-White-Red River Basin Pilot Study Alan Rea

2. Overview Project Goal: Estimate Hydropower potential on each stream reach and total Hydropower potential in U.S. (Cooperator: INEEL/U.S. Department of Energy) Data Needed: Drainage Area, Avg. Ann. Precip, Temp, Mean Ann. Flow, Elevation (head) change on each reach Pilot Study Area: Arkansas-White-Red River Basin (Hydrologic Region 11)

3. Basic Approach Compute catchment characteristics Extract node elevations for synthetic streams Append catchments, synthetic streams for Ark, White, Red Rivers For each catchment, trace upstream network, select polygons, aggregate basin characteristics Compute flow, power potential estimates on synthetic streams

4. Stream Reach Flow Estimation EDNA catchments were overlaid with climate data from the Oregon State University PRISM Dataset  Mean annual precipitation  Mean annual temperature Stream flow regression equation from: Vogel, Wilson, and Daly (1999), “Regional Regression Models of Annual Streamflow for the United States”: Journal of Irrigation and Drainage Engineering, May/June 1999, p. 148-157

5. Stream Reach Flow Estimation (Cont.) Stream Flow Regression Equation Arkansas White Red Region Q 11 = e -18.627 A 0.96494 P 3.8152 T -1.9665 where Q is the mean flow for a site in Region 11 (A-W-R), in cubic meters per second A is drainage area, in square kilometers P is mean annual precipitation, in mm/yr T is mean annual temperature, in degrees Fahrenheit times 10

6. Basic Approach (one gory detail) Node elevations: Two Approaches  Node elev from Filled DEM  Min elev (orig DEM) within 3-cell buffer of nodes (Grid FOCALMIN function)

7. Results Processed, computed estimates for 78,993 catchments Flow and drainage areas compared for 283 stream gages. D.A.’s mostly differ by < 5% Hydropower estimate: 5.5 million KW Fill vs. Focalmin-based power estimates differ by < 1 % for Arkansas, White, < 3% for Red

8. Caveats: Flow equation valid range: 25 – 44,000 sq. mi. EDNA Stage 1B errors  Synthetic stream network errors  Mismatches between EDNA tiles  Noncontributing areas connected  Flow reductions in High Plains

12. Conclusions We can do some very useful analyses with EDNA Stage 1B data You have to be careful with the results Many errors cancel out or self-correct as you go downstream