Slide 1

Organization of the YRDSS

Principal driver is Bureau of Reclamation systems operation model, RiverWare.
Output from RiverWare used as input to linked models for other components, or exported directly to YRDSS.
YRDSS consists of multiple, linked Excel workbooks, automated by Visual Basic macros.

Decision Variables in the YRDSS

Habitat responses for selected target (fish) species.
Temperature changes during important biological time windows.
Water availability and proration rates.
Reservoir storage and passage for bull trout and smolts from selected reservoirs.
Overbank flows and potential flood damages.
Sediment transport.

Time series analysis

All decision variables quantified over a 22 year period of record: WY 1982 – WY 2003.
Results displayed for each year and summarized for period of record.
Some variables (e.g., proration rates) displayed monthly.

Information Flow for YRDSS Decision Variables

DSS OUTPUTS

Summary scores pages
Annual scores pages
Duration series plots
Flow and temperature duration curves
Flow and storage time series plots

Habitat Time Series

Floodplain reaches – Easton, Kittitas, Naches, Union Gap, and Wapato.
Target species – Spring Chinook, Fall Chinook, Coho, Steelhead, Rainbow Trout, Bull Trout.
Life Stages (variable by species) – Spawning and Incubation, Fry, Sub-yearling (winter and summer), Yearling, Adult.

Derivation of a Habitat Time Series

Derivation of a Habitat Versus Flow Functions

Special Case for Spawning and Incubation Habitat

Special Case for Spawning and Incubation Habitat

Derivation of Temperature Data

Stream Network Temperature Model (SNTEMP) Designed and Calibrated for Upper Yakima Basin by USGS Washington Water Science Center.
Daily Flows and Reservoir Releases Input from RiverWare for Baseline and Alternative Operations.
Scoring Based on Changes in Max/Min During the Hydroperiod Defined for Each Life Stage.

Overbank Flow and Floods

Overbank flows considered beneficial, but damaging floods detrimental.
Overbank flow defined as maximum daily flow with 1.67 year recurrence interval (Default).
Damaging flood defined as maximum daily flow with 25 year recurrence interval (Default).
Scoring based on frequency of either under baseline and alternative.

Deliveries and Exports

Total Water Supply Available (TWSA) and Proration Rates derived directly from RiverWare.
Scoring based on percentage differences in TWSA and Proration for baseline and alternative, monthly, from April through September.

Sediment Transport (under construction)

Four aspects considered:
- Redd Scour
- Fine Sediment Transport
- Armour Disruption and
- Geomorphic Processes.

Redd Scour – Scored as Frequency of Flows During Spawning/Incubation Window, Capable of Moving Redd Substrates.

Redd Scour – Scored as Frequency of Flows During Spawning/Incubation Window, Capable of Moving Redd Substrates.
Fine Sediment Transport – Scored as Difference in Total Mass Transport of Sand and Smaller Sized Sediment.
Armour Disruption – Scored as Frequency of Flows Capable of Mobilizing the Armour Layer.
Geomorphic Adjustment – Scored as Annual Sum of Geomorphic Work Done.