HOOD RIVER TRIBUTARIES DRAFT AREA WEIGHTED SUITABILITY Presented
HOOD RIVER TRIBUTARIES DRAFT AREA WEIGHTED SUITABILITY Presented by: Thomas Gast, Normandeau Associates Presented to: Hood River Water Planning Group Instream Flow Subcommittee June 17, 2013
AREA WEIGHTED SUITABILITY What is it? • AWS = WUA – weighted useable area • An index of suitable physical habitat availability • NOT an actual area • Presented as a relationship to flow • Calculated from each sample point (station) along study transects
AREA WEIGHTED SUITABILITY How is it calculated? • The index of suitability of each station component is multiplied together and weighted by the area it represents – Habitat Suitability Criteria (HSC) applied to: Depth Velocity Attribute • Cover • Substrate
AREA WEIGHTED SUITABILITY What does it mean? • AWS is determined from: – Depth suitability – Velocity suitability – Attribute (substrate/cover) suitability • Weighted by stream area represented AWS does not include • Temperature • Dissolved Oxygen • Suspended Sediment • Or anything else (flow availability!)
AREA WEIGHTED SUITABILITY How do you use it? • Use a historic flow time series record • Compare alternatives – How does each alternative alter habitat availability for each species/life-stage? • Limit frequency and extent of low values • Balance competing life-stages and use of water • Consider management strategies
HABITAT TIME SERIES ANALYSIS 1. A time period is selected which corresponds to a species’ life stage of interest. The time period here is July-December for Spawning Chinook Salmon. For this example, day 123 (October 31) is selected for the example. The flow corresponding to day 123 is 246 cfs on this hydrograph. 2. 3. The habitat index that corresponds to 246 cfs is found on the Chinook Salmon Spawing AWS curve at ~ 25000. H A B I T A T I N D E X
HABITAT TIME SERIES ANALYSIS 4. The Habitat Index of 25000 corresponding to day 123 is plotted to develop a Habitat Index Time Series. 5. To complete the Habitat Index Time Series, all the remaining days and corresponding habitat index are plotted.
HABITAT TIME SERIES ANALYSIS In the previous example, one streamflow time series was considered and in the Water Planning Study, a different streamflow time series will be generated for each of the 32 alternatives at each IFIM reach. To evaluate the Habitat Suitability for each of these alternatives the following steps will be completed: 1. 2. 3. The Habitat Time Series will be rearranged by probability of exceedance, similarly to a Flow Duration Curve, where Habitat Index values replace flow. The “Habitat Duration Curve” will then be generated for each of the 32 alternatives. The alternative with highest cumulative habitat index is more favorable to the species during the period selected.
EAST FORK HOOD RIVER Lower Site
EAST FORK HOOD RIVER Lower Site
EAST FORK HOOD RIVER Lower Site
EAST FORK HOOD RIVER Lower Site
EAST FORK HOOD RIVER Upper Site
EAST FORK HOOD RIVER Upper Site
EAST FORK HOOD RIVER Upper Site
EAST FORK HOOD RIVER Upper Site
WEST FORK HOOD RIVER
WEST FORK HOOD RIVER
WEST FORK HOOD RIVER
WEST FORK HOOD RIVER
WEST FORK HOOD RIVER
GREEN POINT CREEK
GREEN POINT CREEK
GREEN POINT CREEK
GREEN POINT CREEK
NEAL CREEK
NEAL CREEK
NEAL CREEK
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