AN INTEGRATED APPROACH FOR THE ASSESSMENT AND DEVELOPMENT OF RENEWABLE GROUNDWATER RESOURCES IN THE QUETTA VALLEY, PAKISTAN

Quetta valley (Lat: 29045'-30020', Long 66050'-67015') is part of Quetta Basin (Lat: 29045'-32020', Long 66050'-67015'), located in Balochistan, the largest province in West Pakistan. The climate in this province is typical of deserts elsewhere, low rainfall (~100 mm/yr) and extreme variations in temperatures. Water scarcity leads this research to address urgent need for assessment and development of groundwater resources. We adopt an interdisciplinary approach integrating remote sensing data with observations extracted from other data sources such as geochemistry, field geology, drilling, geophysics, and modeling, to identify locations of potential productive wells and to develop sustainable extraction scenarios. Quetta Valley consists of a tectonic depression, buried valley, and karstic bedrock. Aquifers are located near the foothills of the Murdar and Mian Ghundi regions. In the NW, there is the Saumungli-Baleli water gap, about 10 km wide, which connects the Quetta Basin with Bostan-Pishin Plain. The drainage of the Quetta Basin finds its way out through this gap and joins the Pishin Lora River. To the NE of Quetta there is gap which connects Quetta to Kach Basin. Rock formations range from Jurassic to modern deposits with rocks types consisting mostly of limestones and shales. Due to the extensive faulting and jointing in the area it is believed that there are opportunities for groundwater entrapment in these fractured systems. In order to assist the assessment of renewable water resources a web-based GIS was created (http://www.esrs.wmich.edu/groundwater__resources_in_quetta_pakistan.htm), which include categories such as: geophysics, geology, land use, precipitation, and remote sensing data sets. Specifically, the web-based GIS includes: Landsat TM Mosaics, Digital Topography (SRTM 90m), Sir-C radar images, spatial drainage patterns, geologic maps, including fault and well locations, and soil maps. Based on the current and future data we wish to determine where current and potential water sources are located. Currently the main water source is groundwater pumped by karezes located mainly in alluvial fans, but over-pumping has caused the water table to drop, and has also caused salinization. Potential resources are groundwater in unconsolidated alluvial deposits and in fractured bedrock.