Application of the FEWS Stream Flow (SF) Model to the Limpopo

Basin, Mozambique Final Report

Tanya Hoogerwerf

OVERVIEW

Mid-Semester: Obtained the FEWS SF Model and text files, but no user information.

Progress Report: Figured out what to do with .avx file and Hydro1k data.

Final Report: Determined linkage between the GIS and rainfall-runoff simulation model; and successful at using 60% of model’s capabilities

The FEWS Stream Flow Model Spatially-lumped continuous soil moisture

accounting model Inputs (all grids) include Hydro1K, NOAA

estimates of daily rainfall totals, USGS land use/land cover dataset, and FAO soils layer

Gulied A. Artan of the USGS provided this model and text files that result when the model is applied to the Limpopo basin in Mozambique

Exploring the Components of the FEWS SF Model in ArcView

Fewsflood.avx added to EXT32 ArcView folder Route.exe added to the BIN32 ArcView folder

Text files supplied are organized by level 5 Pfafstetter codes

These included basin.txt, evap.txt, parameter.txt, rain.txt and response.txt

Run route.exe

route.exe

Data Collection- Hydro1K

Hydro1K

Additional Datasets

Need Derived Soils Properties files!!

Data Preparation

The required grids for the FEWS SF Model are a DEM, CN grid, Soil Water Holding Capacity Grid, Hydraulic Conductivity Grid, Soil Depth Grid, Texture Grid, Precipitation Grid, Evaporation Grid and Velocity Coefficient Grid

No information on model units, used text files instead (recycling data)

Hydro1K Preparation (DEM)

Match Hydro1K Pfafstetter Level 5 Basins

Additional Grids

Text files imported into Excel Saved as a .dbf files In ArcView the fields were joined by Pfafstetter 5

digit codes New field created Shapefile converted to a grid

GRIDS

Running the FEWS SF Model

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Complete Terrain Analysis

User supplies DEM FEWS SF Model creates missing grids and

shapefiles (Downstream Grid, Hill Slope Grid, Hill Length Grid, Basins Grid, basply.shp, Outlets Grid, StrLinks, Streams, FlowLen, FlowAcc, and FlowDir

Final threshold chosen to be 3,000 cells

Generate Basin Characteristics File

INPUT: Basins Grid, Elevations (DEM), Flow Accumulation Grid, Hill Length Grid, Hill Slope Grid, CN Grid, Water Holding Capacity Grid, Soil Depth Grid, Hydraulic Conductivity Grid, Downstream Flow Length Grid, Stream Link Grid, Downstream Grid, and Max Impervious Grid

OUTPUT: basin.txt

Generate Basin Response File

INPUT: Velocity Coefficient Grid, Basins Grid, Flow Direction Grid, Stream Outlet Grid

OUTPUT: response.txt

Generate Rain/Evap Data Files

INPUT: Basin Grid, Rain Grid and Evaporation (as rain_19991 and evap_19991)

Can extract rain, evaporation or both OUTPUT: rain.txt and evap.txt

Perform Flow Routing

INPUT:

Utilizes route.exe and previously created txt files Errors!!!

Perform Flow Routing Continued

Compute Rain/Evap Statistics

INPUT:

Select statistic to be computed

Compute Rain/Evap Statistics Con’t

OUTPUT:

Compute Flow Statistics and Display Flow Percentile Map

INPUT: ?????

Errors!!!

Display Flooded Area Map

INPUT: Processed DEM, Stream Links Grid, Flow Accumulation Grid, flow depth (riverstage.txt), day

OUTPUT: Zone of Influence Grid and Flooded Area Grid

CONCLUSIONS Still a few small flaws in the model With a simple set of instructions,

could be easy to use Wide range of

applicability for

large basins Ready for a trip to

MOZAMBIQUE!

http://mozambique.gecp.virginia.edu/Floods/mozapic34.jpg

SPECIAL THANKS

Gulied A. Artan Jordan Furnans