Land Surface Zoning Approach Based on Three-Component Risk Criteria for Groundwater Quality Protection

Protecting the quality of groundwater is a necessity that requires significant restrictions on land use. Because such restrictions are of complex socio-economic consequences, they should be carefully adjusted to the spatially varied protection needs. This paper describes the development of a series of maps designed to facilitate groundwater protection decisions according to land surface zoning. The zoning was based on attributes descriptive of the basic elements of risk (hazard, exposure and consequences) to groundwater quality in Kuwait to provide basis for adjusting the protective regulations to the needs. Standardized maps of the major categories of potentially hazardous activities were prepared using ArcGIS. A country scale map combining and ranking all the hazardous activities was prepared using the USEPA's hazard ranking system (HRS). The intrinsic vulnerability of the groundwater was mapped using the DRASTIC model. The relative value of the groundwater was mapped according to the three-component criteria of current and future dependence on groundwater, as well as interaction with environmental resources, which were adapted from USEPA criteria for prioritizing the protection/remediation funds. Agricultural activities and oil-related industries were ranked the most hazardous activities in Kuwait. The patterns of the intrinsic vulnerability seemed to be dictated by the depth to the groundwater and the material of the unsaturated zone. Decision making tools were produced by combining the above maps as follows: (1) vulnerability and hazard maps to produce the risk map, (2) risk and value maps to produce the value weighted risk map, and (3) vulnerability and value maps to produce release consequences map. The produced maps should serve the purposes of identifying all potential monitoring targets, prioritizing of funds allocation for monitoring or other corrective actions, and adjusting the land use restrictions to the needs as well as allocating future potentially hazardous land use, respectively. Benefits of including the groundwater value in the criteria for protecting the resource were illustrated by comparing the decisions that would be logically made based on schemes with and without groundwater value as part of the criteria.