ABSTRACT
From 1981 to 1985 BRGM has carried out a large-scale (375,000 km2) hydrogeological study of the north-western part of the Kingdom of Saudi Arabia. Based on data collected during field surveys and exploration drilling, a numerical groundwater model of the Saq aquifer and overlying aquifers was developed, providing guidelines for irrigation-development plans. Since then, major agricultural development has taken place and adverse drawdown affects several aquifers. In 2005–2006, two new models were developed to improve the geological and hydrogeological understanding of the area. Developing simulation models covering such a large surface area with a complex hydrogeological structure requires many technical difficulties to be overcome as well as large scale field- and remote-sensing data campaigns. Despite such difficulties, the 2006 mathematical groundwater model appears to be an effective tool for understanding groundwater flow patterns in the Saq and overlying aquifers.
