1. Monitoring for Flood and Water Supply Forecasting
Robert K. Hartman
RKH Consulting Services
Former Hydrologist in Charge (retired)
NOAA/NWS California-Nevada River Forecast Center (CNRFC)

2. Mission of NWS Hydrologic Services Program
Provide river and flood forecasts and warnings for the protection of lives and property

3. Mission of NWS Hydrologic Services Program
Provide basic hydrologic forecast information for the nation’s environmental and economic well being

4. NWS River Forecast Centers

5. CNRFC Customers RFC WFOs Public Warnings
Water and Flood Management Agencies, Utilities

6. Available CNRFC Forecasts
Short Range … … … … Medium Range… … … … … Long Range
0-5 days days > 14 days
Driven by weather forecasts
& scheduled reservoir releases
Driven by climatology
Driven by a combo of weather forecasts & climatology

7. Deterministic Streamflow Prediction
Daily RFC Operations
Data Ingest
Data QC + Processing
Model Updating
HAS Unit
Operations
Forecast
Mean Areal
Time Series
Precipitation
Temperature
Freezing Level
CHPS
Hydrologic
Models
Current Conditions
Soil Moisture
Snow water
Reservoir Levels
Streamflow

8. River Guidance ~300 flood, non-flood, and reservoir locations
Updated w/each model run
2x / day winter weekdays
1x / day summer weekdays and weekends
4x / day during flood events (

9. Ensemble Streamflow Prediction
HAS Unit
Forecasts
Daily RFC Operations
Data Ingest
Data QC
Model Updating
Current Conditions
Soil Moisture
Snowpack
Reservoir Levels
Streamflow
Historical
Time Series
All Years of
Record
Numerical
Weather
Model
Mean Areal
Precipitation
Temperature
CHPS
Hydrologic
Models
Time
Flexible
Period of Interest
Thanks to Steve Shumate, CBRFC.
Met
Ensemble
Preprocessor

10. CNRFC Ensemble Forecasts
Updated daily
~230 locations
365 day duration
10 standard graphics
Build your own interface
Includes 14 days of weather forecasts

11. Surface Data Collection
California
Cooperative
Snow Survey
AWIPS
text products
NRCS
(SNOTEL)
State & Local
Resource
Management
Agencies
ASOS
CNRFC
Database
California
Data
Exchange
Center
Bureau of
Reclamation
11 WFOs
(ALERT)
ALERT
Reception
GOES
DCPs
Corps of
Engineers

12. Required Surface Observations
Precipitation
Air Temperature
River Gage Height
Reservoir Elevation
Reservoir Releases
Snow Water Equivalent
Wind Speed
Wind Direction
Surface Pressure

13. Precipitation Observations

14. Issues with Precipitation
Coverage in many watersheds is marginal or inadequate
Significant effort to quality control data, especially as we move to hourly duration
Problems with measurement of solid precipitation
Problems with inconsistent wind shielding
Unknown problems with site maintenance
Need a true multisensor process that dynamically integrates radar, satellite, rain gauge, model, climatology, and other surface data

15. Surface Air Temperature Observations

16. Issues with Temperature
Fewer and less severe than precipitation
Coverage in some watersheds is marginal or inadequate
Quality control is required, but can be largely automated
Inversions and unusual lapse conditions make assessment and spatial distribution difficult
Historical archives are mostly max/min, yet application is 6- hourly or hourly. Calibration issue.

17. River / Reservoir Gage Height

18. Issues with River/Reservoir Data
Observations are not necessarily available where you need them
Good calibrations require good historical records
Gauging and maintenance are expensive and agencies are not adequately funded
Quality control requires and understanding of what flow is expected, which requires some sort of model
Conversion of stage to flow
Requires up-to-date rating curve
Problematic at some locations
Scour and deposition during a flood event
Not all diversions are measured

19. Snow Water Equivalent Manual snow courses Automated sensors SNOTEL
CA Cooperative Snow Survey Program

20. Issues with Snow Data
Snow courses are excellent quality, but only read monthly
Snow pillows provide near-realtime information, but have their own issues
Mid-winter failures can’t be repaired
Bridging and creep
Limited resolution and pressure measurements make high frequency (sub-daily) assessment difficult

21. Current Delta Forecasting
5 locations
Sacramento
Rio Vista
Mallard Island
Antioch
Venice Island
Turning points only
Highs and lows
Stage
Two days into future
Issued daily+
No ability to handle breaches

22. Summary
Monitoring for flood and water supply forecasting is accomplished by a community of federal, state, and local agencies and the private sector
Observations and streamflow forecasts are critical to Delta management by multiple agencies
The California Data Exchange Center (CDEC) within DWR serves a key roll in making data available to everyone
Data collection efforts and funding should be prioritized and supported

23. Thank You