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The FEWS Flood Risk Monitoring Model From Rain to Rivers

The FEWS Flood Risk Monitoring Model From Rain to Rivers. Tanya Hoogerwerf Thursday, February 22, 2001. FEWS Model. Provides a continuous simulation of stream flow, on a daily time step, for nearly 3,000 basins on the African continent. Rainfall/runoff simulation model containing…

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The FEWS Flood Risk Monitoring Model From Rain to Rivers

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  1. The FEWS Flood Risk Monitoring ModelFrom Rain to Rivers Tanya Hoogerwerf Thursday, February 22, 2001

  2. FEWS Model • Provides a continuous simulation of stream flow, on a daily time step, for nearly 3,000 basins on the African continent. • Rainfall/runoff simulation model containing… • a soil water accounting module that produces surface and sub-surface runoff for each sub-basin • an upland headwater basins routing module • and a major river routing module.

  3. Runoff Producing Mechanisms • Surface runoff due to precipitation excess (including direct runoff from impermeable areas of the basin) • Rapid Subsurface Flow (interflow), and • Base Flow

  4. Soil Water Accounting Module (SAC-SMA) Revisited FEWS: Active Zone (2 layers) & Groundwater Zone (1 layer) Active Layer Baseflow

  5. Runoff Calculations • The HYDRO1K data provide basin boundaries and stream networks that form the spatial framework of the model. • The FAO soil map provides characterization of the hydraulic properties of the earth's surface that are required to compute the water balance within a basin. • The NOAA RFE provide the estimates of gross precipitation input to each basin.

  6. Total Channel Inflow (SAC-SMA) uT = Channel Inflow from SWC= Surface Runoff + Base Flow Runoff Surface Runoff = f(Precipitation, Soil Water Content, SR Gen.) Base Flow Runoff = f(BF Recession Rate, SWC, BF Lost to Aquifers) Water Balance Relationship for Each Reach: dSidt = Ui-1 + pi*uT – Ui S=Water Volume Pi = Fraction of Total Water Inflow Corresponding to Reach i Ui = Reach i Ui-1 = Upstream Inflow from Reach i-1

  7. Time of Concentration Grid • Slope, flow direction, and flow accumulation grids of the HYDRO1K • Manning equation for flow in an open channel • Units: 1/10 day

  8. Rainfall • NOAA has produced RFE images (Herman et al., 1997) on a dekadal (10-day) time step • Basin Excess Rainfall Maps (BERM) Produced

  9. Output Mozambique Flood Information Stream Flow Model Flood Risk Map Page (select Pfafstetter Basin)

  10. USGS/EROS Data Center http://edcsnw3.cr.usgs.gov/ip/gflood/ Riverside Technology Real-Time Prediction for Flood Warning and Management- Georgakakos 1995 Coupled Rainfall-Flow Forecasting Models- Georgakakos References

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