Western Water Supply

Kevin Werner, Andrew Murray, WR/SSDJay Breidenbach, WFO Boise

Cass Goodman, Steve Shumate, CBRFCAlan Takamoto, Scott Staggs, CNRFC

Don Laurine, NWRFCChad Kahler, WFO Tuscon

Outline

• Western Water Supply– History

• Project overview– Westwide map– Forecast evolution– Verification– Ensemble services

• Future enhancements– Climate variability and change– Short range ensembles services

Western Water Supply Forecasts

•Forecasts for spring runoff amounts from snow melt dominated basins in western US

•Routinely produced at 6 RFCs and coordinated with other agencies (NRCS and California DWR)

•NWS forecast program began in 1940s

•Primary forecast tools:– Ensemble Streamflow Prediction– Multivariate Linear Regression

Legacy Water Supply Forecast Product (Credit: NRCS / NOAA)

Project in a Nutshellwww.cbrfc.noaa.gov/westernwater

Map: Single map for all western WS forecasts from 6 RFCs

Forecast evolution: Plotting capability to show evolution of current year forecast and observed river flow

Verification: Forecast evaluation from past forecasts and forecast tools

Ensemble services: Interaction capability with ensemble streamflow predication

Data Access: Access data from database

Milestones• Milestones (past):

– April 2005: Working group formed, planning meeting held– January 2006: Initial website launched– September 2006: Included AB, WG, and MB RFCs in development– January 2007: Common database developed– March 2007: Launched outreach effort and included SHs– September 2007: Move software to NWRFC web farm

• Milestones (future):– December 2007:

• Launch verification 1.0 capabilities• Launch forecast evolution 2.0• Launch ensemble services 1.0

– January 2008: Integrate WGRFC data– 2008?: Integrate climate change capabilities

Map

www.cbrfc.noaa.gov/westernwater

• “One Stop Shop” for NWS water supply forecasts

• Flexible and consistent map presence across western USA

• Zoomable to basin scale

• Mouse over capability for forecast values

Forecast Evolution

Time evolution of forecast and observed streamflow

Plot options include:

-Observed monthly or seasonal streamflow

-Historical monthly or seasonal streamflow

-Forecast seasonal streamflow

-Accumulation options

Forecast Evolution

Version 2.0

coming December 2007

Additions include:

-ESP seasonal forecasts for easy comparison to official forecasts

-Multi-year plots

Ensemble ServicesDecember 2007

RFC Ensemble Forecasts

-Initially offered at NWS water supply points

-Display probability function for monthly volumes

-Tools included to query historical data and forecast ensemble members

-User customizable plots

Ensemble ServicesDecember 2007

Median Historical Runoff

& 1983 ensemble member

November – May Seasonal Runoff

Forecast VerificationDecember 2007

Data Visualization Error• MAE, RMSE, etc• Conditional on

Lead time, year

Skill• Skill relative to

Climatology• Conditional

Categorical•Traditional (NWS) verification including FAR and POD• Category definitions tied to climatology values (e.g. mean flow, terciles, etc.) or user definable

•Easy to understand• Meaningful• Accessible from forecasts• Dynamically generated plots from database

Plot credit: Chad Kahler

Data AccessDecember 2007

•Access to forecast and observed data from database

Future Directions

Climate Change Hydrologic Scenarios

Short Range Hydrologic Scenarios

Climate Variability and Hydrologic Response Relationships

Figure TS.5 (IPCC AR4, WG2). Illustrative map of future climate change impacts on freshwater which are a threat to the sustainable development of the affected regions.

Climate Change:Fresh Water Projections

Extend NWS Product Suite?

• Current product suite covers hours to seasons;• Should we consider climate change scenarios and

build multi-year products for run-off, temperature, precipitation?

• User requirements from power companies, BoR, etc for climate change scenarios

Climate Change run off scenarios?

Years

Climate Change Scenarios

Example: Lake Granby inflows on the Colorado River

Two temperature scenarios:

•Historical Temperatures

•+0.2 deg F increase per year based on historical temperatures

Climate Change Scenarios (Con’t)

Corresponding simulations of Lake Granby inflows:

•Warmed simulation has earlier runoffs late in the simulation

Climate Change Scenarios (con’t)

Hungry Horse Dam inflows on Flathead River

Simulations with 1% less precipitation per year

Climate Change Scenarios (con’t)

• Ultimately include climate change scenarios in the ensemble services application for easy comparison with other datasets.

Summary

• www.cbrfc.noaa.gov/westernwater

• New stuff coming in December

• We like feedback: kevin.werner@noaa.gov