Abstract
Urumqi is located in the remote center of the Eurasian continent. It is a future mega-city with rapid economic development and high population density in China's western interior. Urumqi's water resource problems are the main research objects in this thesis. Several models have been put forward to predict water demand in Urumqi and useful suggestions have been gathered to reduce water scarcity. In 2010, the average annual water resources of Urumqi were at 939.22 million m³ and the average per capita water resources were 387 m³, meaning that water resources are inadequate in Urumqi. The water consumption in Urumqi already exceeded the total amount of water resources. Furthermore, almost half of the wastewater is discharged directly into rivers and wasteland in Urumqi and as such, both surface water and groundwater are seriously polluted. Since there is also no reasonable water price system, the price of water is relative low which leads to weak awareness of water conservation. In addition, the high leakage rate of the pipe network and the backward technology of agricultural irrigation have resulted in serious water losses. In order to alleviate the scarcity of water resources and instead increase the number of resources, while at the same time improving water quality, wastewater in Urumqi and how it is reused of Urumqi was analyzed. Some suggestions about Urumqi's sewage and water reuse system were put forward. Moreover, various water scarcity assessment indexes were used to evaluate the water scarcity risk in Urumqi. Based on the results of a water scarcity risk assessment, the water scarcity decision was built up by adopting the advanced Analytic Hierarchy Process (AHP) methodology. The measures to reduce water scarcity include a.o. adjusting industrial structures, water conservation, using unconventional water resources, implementing economic regulation measures, controlling environmental safety, improving urban functions, and the interbasin transfer of water. According to the results of the analysis of water scarcity decisions, major solutions to resolve the problem of water scarcity were identified, with water conservation as the most important step in reducing water scarcity in Urumqi. In addition, a water conservation index system was set up based on the water-saving evaluation standard in China to change the present situation of serious wastage of water resources in Urumqi. This index system can be used to reflect the problems (e.g. high leakage rate of the water supply pipe network, low water price, low conveyance efficiency of irrigation canal system, low rate of recycled industrial water and water conservation awareness) and the potentials of water conversation in each sector (agriculture, industry and domestic). The results of the index system show that there is a large potential of agricultural water conservation, and it can be achieved by several measures, such as improving the water efficiency of the canal system, promoting the usage of advanced water conservation irrigation techniques and increasing the water price for agricultural irrigation. In addition, the method and the model (used to analyze the system, which related to time includes both certain and uncertain information) were used to predict water demand. The method predicts the water demand based on indicators of socioeconomic development and the water use quota in each sector. The model was constructed according to the time series of agricultural, industrial, domestic and total water consumption in Urumqi from 2003 to 2010 by creating a sequence of first-order accumulated generating operation and differential equations. The predictions that were calculated by using the grey show that agriculture will still be the biggest user of water in 2015. Therefore, changing the agricultural system and improving the efficiency of agricultural water use are the best ways to realize the rational allocation and sustainable use of water resources in Urumqi. In order to effectively manage Urumqi's water resources and to integrate the water demand prediction and the water scarcity decision model, the water resources management and information system for Urumqi was built up by using various technologies (database, Web and GIS server). This system not only reflects the current situation of Urumqi's water resources but also helps users to make decisions for reducing water scarcity.
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