Global Hydrologic Data Development presented by Kwabena Asante acknowledgements Dr David R. Maidment Dr Francisco Olivera Dr Jay Famiglietti Center for Research in Water Resources The University of Texas at Austin

GIS Hydro ‘99: Digital Atlas Digital Atlas of the World Water Balance The Digital Atlas contains 24 grids 6 coverages of processed terrain data for continental scale hydrologic modeling including

Data Structure

Preprocessing Data 30” DEMs from EROS Data Center, USGS Lower datum Mean Sea Level New Reference Datum Lower datum 1 km Project

Basic Map Projections

Projection Parameters Lambert Azimuthal Equal Area Projection Cell size: 1000 m Projection Centers as defined by the USGS: Continent Longitude Latitude Africa 20o 0’ 0” 5o 0’ 0” Asia 100o 0’ 0” 45o 0’ 0” Australia 135o 0’ 0” -15o 0’ 0” Europe 55o 0’ 0” North America -100o 0’ 0” South America -60o 0’ 0”

Projected View North America Europe Asia South America Africa Australia

Europe - Asia Divide Considerations: Drainage Basins No. of Grid Cells Europe = 28 million Asia = 48 million Caspian Sea Drainage Basin Area = 5.4 million km2

Pits and Inland Catchments Assign NODATA Cells Inland Catchments Other Pits Fill Identify inland catchments and fill all other pits

27 Major Inland Catchments

Processed Terrain Grid

Flow Direction Grids 1 2 4 8 16 32 64 128

Flow Length Grids

Flow Accumulation Grids

Defining Basin Outlets: 3o Ocean Boxes

1500 Major Drainage Basins

USGS Hydro1k Delineation Watersheds from USGS delineation Drainage Basins from this delineation

GIS Hydro ‘99: Digital Atlas Digital Atlas of the World Water Balance Processed terrain data Major Drainage Basins Processed Terrain Grids Flow Direction Grids Flow Length Grids Flow Accumulation Grids Documentation of the data development Links to previous versions of the atlas containing global hydrologic data including Precipitation Temperature Radiation Soil Water Holding Capacity

Conclusions Derived hydrologic modeling parameters from the finest terrain data available Delineated Drainage Basins for sections of coastal-line using these data

I’m done