# Presentation: 076263

## Western Water Supply

**Kevin Werner, Andrew Murray, WR/SSD**
- Jay Breidenbach, WFO Boise
- Cass Goodman, Steve Shumate, CBRFC
- Alan Takamoto, Scott Staggs, CNRFC
- Don Laurine, NWRFC
- Chad Kahler, WFO Tuscon

*RFC Verification Workshop, 08/14/2007*

## 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)

**Notes:**
The NWS started making water supply forecasts in the 1940s for the Colorado basin. Eventually these forecasts were expanded to cover most western snow melt dominated basins through cooperation with the NRCS. Seasonal streamflow forecasts tradionally derive nearly all of their skill from current snowpack conditions in the basin. In fact, the NRCS SNOTEL network was deployed beginning in the late 1970s explicitly to improve seasonal streamflow prediction. 

Bullets on left give background information on water supply forecasts.

The upper right figure is hyperlinked to “live” website (www.cbrfc.noaa.gov/westernwater).  - Suggest clicking on website and giving a brief synopsis of current forecasts for western US. Note that most areas are extremely dry this year – particularly most all of California and the Colorado Basin. The Washington Cascades and the upper Arkansas River Basin are the only areas with above normal forecasts this year.

## Project in a Nutshell 

**Goals:**
- A “one stop shop” for NWS water information at the seasonal timescale
- Consistent presentation of products between RFCs
- Harness collective innovation from multiple offices
**Users:**
- Existing Water Supply forecast users
- Strong support from USBR and state water resources agencies for examples
- Groups with cross basin interests (e.g. media, power companies)
- NWS internal uses
**Major Components:**
- Map: Single map for all western WS forecasts from 6 RFCs
- Forecast evolution: Plotting capbility to show evolution of current year forecast and observed river flow
- Verification: Forecast evaluation from past forecasts and forecast tools
- Ensemble services: Interaction capapility with ensemble streamflow predication

## Project in a Nutshell (con’t)

**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
**Milestones (future):**
- August 2007: Launch verification 1.0 capabilities
- September 2007: Move software to NWRFC web farm
- October 2007: Launch forecast evolution 2.0
- October 2007: 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

**Notes:**
Highlight collaborative relationship with NRCS and consistency with legacy products

## Forecast Evolution

- Evolution of current year forecast and observed streamflow
- Options to include:
- Normal streamflow volume
- Forecast window
- Forecast accumulation
- Etc
- Originally developed at NWRFC
- Version 2.0 contract development work proceeding
- Add ESP forecasts
- Add interactive features

## Forecast Verification

| 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
 |

-  Goal: Provide users of all types with forecast verification information
-  Easy to understand
-  Meaningful
-  Accessible from forecasts
-  Dynamically generated plots from database

- Plot credit: Chad Kahler

## Ensemble Services

- Goals:
- Intuitive user interface for current ensemble forecast
- Access to archived streamflow data for perspective
- Dynamic, flexible plots
- Access to underlying data and database
- Climate change scenarios

## Slide 10

## Climate Change

- Latest IPCC report confirms “temperatures averaged over all habitable continents ... will very likely rise at greater than the global average rate in the next 50 years and by an amount substantially in excess of natural variability.” (IPCC WR1, 2007)

- Source: IPCC, 2007

## Trends in 1 Apr SWE over the 1960–2002 (left) and 1950-1997 (right) periods of record directly from snow course observations  from Mote (2006) and Mote et al. (2005) respectively.

***Trends in 1 Apr SWE over the 1960–2002 (left) and 1950-1997 (right) periods of record directly from snow course observations  from Mote (2006) and Mote et al. (2005) respectively.***

## 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 based run off scenarios?

- Years

## Water Supply withClimate Change

- Many in water community are asking for it
- Idea: Provide scenario based water supply outlooks in the context of historical data and current season forecasts
- Include uncertainty
- Temperature, precipitation, and/or lead time based scenarios
- Ultimately link scenarios to atmospheric carbon based scenarios
- Leverage historical simulation capabilities in ESP

## Leveraging ESP for long range scenarios

- Multiple “historical simulation” runs:
- Use historical basin temperature and precipitation time series
- Build ensemble by repeatedly shifting year order by one
- Incorporate scenarios through additive (temperature) or multiplicative (precipitation) year-wise adjustments

## ENSEMBLE FORECAST SERVICES

**Forecast Point: Columbia River at the Dalles Dam**

| Archive | Current Forecast | Climate Change | Options |
| --- | --- | --- | --- |
| O Normal Runoff
O Model Normal
O Historical Year(s) | O Ensemble Streamflow Prediction O Ensemble members by forcing year(s)
O Ensemble members by ENSO | O Year (slider bar 2010-2050)
O Temperature (slider bar -5 F - +5 F)
O Carbon Scenario | O Accumulate over period
O Plot Type (box and whisker, bar, lines, etc.)
O Data
O Plot interval (set axes limits)
 |

## Summary

- Western Water Supply
- History
- Current capabilities
- Coming enhancements
- Verification
- Water Supply ensemble services
- Climate Change

## Thank you