Land and Water Resource Information Systems By David R. Maidment Center for Research in Water Resources University of Texas at Austin Presented at UN Food and Agriculture Organization, Rome, Italy December 1997

Information System Development Ideas Users Technology Innovation is driven by: users, ideas, technology

Land and Water Interaction Land Characterization (Land use, Soils, Climate, Terrain) Water Characterization (water yield, flooding, groundwater, pollution, sediment) Relationships between land type and water characteristics

Possible Land-Water Transform Coefficients Water Land

Land Use, Climate, Soils and Terrain are each classified into a set of categories For each existing land use-climate-soil-terrain class, use observed data or computer models with weather generators to determine the value of the corresponding transform coefficient Repeat this simulation for all classes to fill in the transform table on a consistent basis Prepare separate tables for world regions Development of Transform Coefficient Tables Water Land

Application of Transform Coefficients Go to a new region and get maps or GIS coverages of land use, soils, climate and terrain if possible, get observed data on climate, water flow and quality, and sediment measurements calculate water characteristics for existing conditions, compare with observed data, and apply an adjustment factor for local conditions if necessary project new conditions as a result of land use change or management plans and determine effects of these changes and plans on the water characteristics

GIS Automation lay a fine mesh of grid cells over the landscape use 10, million cells with cell size 10 m to 1 km depending on size of the region use global or regional data sets to classify each cell as a land use-climate-soil-terrain type apply the corresponding transform coefficients determine runoff, water quality, sediment load for each cell use weighted flow accumulation to get corresponding accumulated values for each downstream cell linklink apply dynamic models where needed (e.g. for flooding) to get additional detail using same GIS land base data