Assessment of potential risk groundwater pollution from agricultural non-point sources

An approach to assess potential risk of groundwater pollution due to agricu ltural practices is presented. The procedure consists in combining a valid point count system model (SINTACS) which evaluates intrinsic aquifer vulner ability, with a parametric approach (AHI indexes) to take into account the hazard level of farming activities. The SINTACS model is based on seven hyd rogeologic characteristics, identified as influencing contaminant transport through the vadose tone to the groundwater system. Sensitivity ratings are developed for each SINTACS parameter that reflect its relative importance to vulnerability. Non-point source agricultural hazard indexes (AHI) are ob tained from the combination of hazard factors (HF) representing all farming activities which cause or may cause an impact on groundwater, and control factors (CF) which adapt the hazard factor to the basic environmental chara cteristics of the site. A geographic information system (GIS) is used to ma nipulate and analyse spatially referenced information, as well as to combin e or overlay individual characteristic maps to create the final cumulative groundwater potential risk map. An example of the application of the proced ure to a case study and results obtained are illustrated.