| The average water resource per capita in Zhejiang Province is 2072 m~3, a little bit lower than the average amount of the country, and only 1/4 of that of the world. Zhejiang has been developing very quickly in economy in recent 20 years, with substantial increase in requirement of water. The relative proportion of water use in agriculture to total water consumption showed a distinct decline in the past years, and in fact the absolute amount of water used in agriculture is also decreasing. Thus there is a severe challenge for food production and safety. On the other hand, water usage in industry and living shows substantial raise, and meanwhile the wastewater released is also dramatically increased, posing a heavy pressure on the environment. Facing the increasingly severe shortage in water resource, especially for agriculture, and the degradation in water quality occurred in some areas, as well as the irrational using of water resource, it is quite important to make a scientific planning, optimize disposition, improve usage efficiency and save water resource by comprehensive analysis of the cause, and systematic study of water resource usage in Zhejiang.1. The Situation of water resource usage and prediction of the water requirement prediction in ZhejiangIn 2000 and 2001, the total water resource and its usage in Zhejiang were basically equal to the average of many years. Thus the mean of the two years are used to demonstrate the basic situation. The total amount of water resource in the province is 95.025 billion m~3, the total amount of water used is 20.325 billion m~3, and used ratio of water resource is around 21.4% and comprehensive amount of water per capita is was 441 m~3. The water amount used in agricultural irrigation occupies a main part of total water usage, being 10.878 billion m~3 and about 53.55% of total water usage. In addition, forestry, stock raising and fishing used 1.043 billion m~3, only consisting of 5.13% of total water usage. Water amount used in industry is 5.278 billion m~3, being 26.02%, and the amount of living-used water in cities is 1.941 billion m~3, being 9.51%, while that used in rural areais only 1.184 billion m3, being 5.93%. The comprehensive water amount for each citizen was 131.5 m3, and 39.15 m3 for each rural person. The amount of water used in crop cultivation is 515 m3 per 667 m2. The water usage for each 10000 GDP is 317 m3.The great change has taken place in the structure of water usage in Zhejiang in recent decades. The proportion of agricultural water usage was constantly reduced, being 70.3% of the total water usage in 1993 and 52.8% in 2004. Correspondingly, the proportion and absolute amount of industry and living water usage witnessed a substantial increase. Thus, the proportion of water usage consumed in industry increased from 20.3% in 1993 to 26.8% in 2004, and that consumed in living jumped to 17.6% in 2002, while in 1993, it was only 9.4%. Compared with other areas in China, Zhejiang had relatively lower proportion of water usage in agriculture, thus in 2002 the value was 10.65 billion m2, and the mean of whole state was 67.96%. On the other hand, the proportion of water usage in industry and living was over the average of the nation.It is estimated that the total demand of food for Zhejiang in 2010 is about 18.4 Mt. If the self-supply is about 55%, as expected reasonably, the total production of 10.2 Mt food should be produced at that time, which is equal to the level of food production in 2001. In that year, the water consumption in agriculture was 11.72 billion m3, in which water used in irrigation was 10.65 billion m3. According to a prediction, the water amount usable for irrigation in 2010 is only 8-8.5 billion m3, indicating the severe water shortage for agriculture.In term of water consumption per 10000 RMB, Zhejiang was only 271 m3, being half of the mean of the nation, indicating high water use efficiency. However, the values in Beijing and Tianjin are about two times as high as that of Zhejiang. Moreover, the difference from that developed countries is quite large. For instance, in 2002, water consumption per 10000 RMB in Zhejiang was 14 times higher than that of Japan and 12 times higher than that of Germany.It is estimated that effectively irrigated arable land in 2010 will be 210 Mha. Taking 480 m3 of water usage for 667 m2, the water requirement for agriculture should be 10.08 billion m3. In order to produce 10 billions kg of food, at least 11 billion m3 of water isrequired in irrigation. Besides, forestry, stock raising and fishing will consume about 1.09 billion m3, which is close to the amount of water consumed annually from 1997 to 2002. Thus, in 2010, the total agricultural demand of water will be 12.09 billion m3. In addition, the industry will use 7.22 billion m3 of water. If the recycled water utilization is increased by 8%, i.e. 1.15 billion m3 of water being saved, due to improved technique innovation. Totally, the amount of water requirement in 2010 is 24.71 billion m3. Of which, the water used in agriculture is almost the same as that in 2002, industry and living water usage will increase 35% and 56%, respectively. Meanwhile, more facilities should be provided for dealing with sewage and wastewater. Therefore, it is a most effective approach for overcoming water problem in Zhejiang to make up the strategies, optimizing water preserving criteria, reducing water usage and sewage or wastewater release.It is possible to reduce water usage by 12.89% compared to predicted value in 2010 through scientific planning, optimized disposition, improved water use efficiency and preserved water, thus optimizing water resource utilization.2. Major problems in water resource utilization in Zhejiang and the comprehensive countermeasuresThe major problems in water resource utilization in Zhejiang are as follows:(1) The water resource per capita is relatively small;being only 2072 m\ lower than that of mean of the nation and 1/4 of that of the World.(2) The difference among the years in water resource is quite large. For instance, in 2003 the total water resource was only 574.48 m3, less than 2/3 of the average of many years.(3) The distribution of water resource in different areas is not comparable to those of the population, economy and arable land. In 2001, the total water resource in 6 northeast cities of Zhejiang consists of only 37.42% of the total amount, while the arable land areas, population and GDP value of these locations was 58.17%, 50.72% and 64.85% of the total amounts, respectively.(4) The water resource utilization has been not low in Zhejiang. From 1997 to 2003, the water resource exploration and utilization rate was higher than 20%. In 2001, the value was 21.92%, being higher than that of the national mean (19.5%), and nearly double than that of the world's mean.(5) Water use is quite extensive and not economic. Water-transporting facilities in agriculture is relatively old and the utilization rate is low.(6) Water supply system in cities shows a high leaking and wasting rate.(7) Recycling utilization of water in industry is still relatively low.(8) Water resource policy and management system are not so advanced, and the water price seems too low.The optimization of water resource management and comprehensive countermeasures for improving water resource utilization should be based on the following the policies or strategies: water saving is placed as priority, sewage control as the principal, optimize the allotment, and scientific management. It should be addressed that it is key important to increase water utilization efficiency and to establish a water saving society. Water user is main objective for investigation. Advance in science and technology relevant to water resource and usage should be highly emphasized. Price policy and water management should be improved to stimulate development of water saving system. Wastewater release should be controlled.3. The main approaches of improving water utilization efficiency in agricultureThe main approaches of improving water utilization efficiency in agriculture are involved in water-saving techniques of agronomy, biology, management and engineering.The water-saving techniques of both agronomy and biology are as follows: reducing the time of wetting fields and water leakage, all kinds of practices for reducing the water evaporation through application of soil covering or of chemicals, and improved cultivation. In addition, insufficient irrigation and dry-wet alternative irrigation should be recommended as they have been proved to be effective to improve water utilization efficiency. To choose and raise anti-drought varieties: to choose to raise the varieties ofcrops that are anti-drought, water economic, good in quality and high in yielding is the major method to solve the contradiction between water saving and high quality and yield of the crops.Development of upland rice: it is a effective way of overcoming the contradiction of high yield and water saving to develop and extend planting of the crop cultivars with drought resistance, less water requirement, high yield and quality. Upland rice consumes much less water than paddy rice.Water saving techniques in engineering: The water-transporting system is refined to improve utilization efficiency of irrigated water. The dyke system is webbed to minimize water leakage and mud dykes are placed by pipelines, thus reducing water loss in transporting, increasing irrigation efficiency, and enlarge irrigation area.Innovation in management: to enhance the water resource management, ensure water supply for agriculture, so as to improve water use sustainability and stimulate sustainable development of society, economy and ecology. |
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