Climate change is transforming the water cycle, thus affecting the availability of water. While climate change is unlikely to have a major effect on municipal and industrial water demands in general, it may substantially affect irrigation withdrawals due to higher temperatures and therefore higher crop evaporative demand. Flood magnitude and frequency could increase in many regions, exacerbated by land-use change, and water quality could degrade through higher water temperatures and increased pollutant load from runoff and overflows of waste facilities (IPCC, 2007).The adverse effects of climate change on water resources will aggravate the impact of other water stresses such as population growth ,economic development, land-use change and urban isation. Water consumption in Qatar is exerting pressures on its natural ecosystem. Measures taken to cope with water scarcity and increasing water demand have contributed to serious ecological problems that encompass the loss of biodiversity and desertification (UNDP,2007).