Methodology For A Cartographic ApproachFor The Assessment Of Agricultural Non PointSource Pollution Risk - Use Of Remote SensingAnd Geographical Information System

Abstract

In the framework of Eureka-ISMAP program (Integrated System and services for the Management of Agricultural Pollution), an Information and Decision-Support System (ISMAP/IDSS) is developed. Among other services, methodologies for mapping agricultural non point source pollution risk are investigated under the program. A methodology applicable when runoff is predominant is presented here. Remote sensing using SPOT or LANDS AT TM (Thematic Mapper) imagery is used to locate the pollutants through the identification of the crops where they are applied. Then, a specific methodology combining surface soil texture and land surface slope through a Geographical Information System (CIS) gives the map of the pollutant's propensity to leave the place where they were applied. Such a map illustrates the surface water vulnerability to pollution due to agriculture where runoff is predominant. Combination of the location of the pollutants and the map of surface water vulnerability to pollution due to agriculture, gives the map of non point pollution risk. A spatial analysis of the influence of vegetation slowing down or stopping the transfers of pollutants in the watershed can be performed in addition. This methodology is applied to the Grand Morin watershed, in the suburbs of Paris, France. This watershed of 1200 km^ is involved in drinkable water problems and has been studied for several years. LANDSAT TM imagery has been used to locate corn, main source of a common pesticide named Atrazine. This spatial mapping methodology for non point source pollution risk under ISMAP is designed to be reproducible in time and space in Europe.