THE BALANCE BETWEEN SUPPLY AND DEMAND OF WATER RESOURCES AND THE WATER-SAVING POTENTIAL FOR AGRICULTURE IN THE HEXI CORRIDOR

The Hexi Corridor is an important base of agriculture development inNorthwest China. According to recent statistics, there are 65. 94 x 10~8m^3 of water resourcesavailable in the Hexi Corridor. At present, net consumption in development and utilization is 43. 33x 10~8m^3. Water supply and demand reach a balance on the recent level of production, but loss ofevaporation and evapotranspiration is as much as 25. 69 x 1010~8m^3. So net use efficiency of waterresources is 59% Based on analyzing balance between water and land considering ecologicalenvironment at present, there exists the serious water shortage in the Shiyang River system whereirrigation lands have overloaded. There is a comparative balance between supply and demand of waterresource in the Heihe River system; and the Sule River system has some surplus water to extendirrigation land. Use of agriculture water accounts for 83. 3% and ecological forest and grass for 6.9% . The Hexi Corridor still has a great potential for water saving in agriculture production.Water-saving efficiency of irrigation is about 10% by using such traditional technologies as furrowand border-dike irrigation and small check irrigation, and water-saving with plastic film cover andtechniques of advanced sprinkler and drip/micro irrigation etc. can save more than 60% of irrigatedwater. Incremental irrigation area for water-saving potential in the Hexi Corridor has beenestimated as 56% - 197% to original irrigation area. So the second water sources can be developedfrom water saving agriculture in the Hexi Corridor under Development of the Western Part of China inlarge scale. This potential can be realized step by step through developing the water-savingmeasures, improving the ecological condition of oasis agriculture, and optimizing allocation ofwater resources in three river systems.

Balance of Water Supply-demand in Paddy Fields in Hilly Regions in Sichuan Province

[Objective] The aim was to study the effects of water supply and consumption on water saving and drought resistance. [Method] Controlling field experiment was conducted to explore water balance between supply and demand in paddy fields in hilly regions in Sichuan Province. [Result] Rainfall in hilly areas was 3 611.10 m3/hm2; water for irrigation was 6 299.25 m3/hm2; evapotranspiration of rice was 6 424.95 m3/hm2; deep leakage was 2 459.55 m3/hm2; overflowing amount was 1 026.00 m3/hm2. In addition, water consumption totaled 8 884.50 m3/hm2 during rice production; water use was 0.99 kg/m3 and use efficiency of irrigated water was 1.40 kg/m3. [Conclusion] Water supply and consumption should be further organized to save water and fight against drought in hilly areas in Sichuan Province.

The Study on Urban Vertical Greening and Balance Water Supply Technology

The paper had analyzed the technology, maintenance and recognition of vertical greening in urban space, and proposed a solution for balance water supply for balconies and streetlights, that is, magnetic auxiliary shallow water level controller, the patent of which had been applied. Magnetic auxiliary shallow water level controller had met water supply of some special parts of urban vertical greening and was sure to accelerate urban vertical greening.

The Estimation of Water Supply and Demand in Hotan Oasis

[Objective] The purpose of this study is to estimate water supply and demand, which can provide a basis for how to allocate rationally water resources in Hotan Oasis. [Method] The water supply and demand in Hotan Oasis in the next15 years were calculated according to water-soil balance. [Result] When the runoff of Hotan River is at a probability of 50%（P=50 for short）, the total water resource is 50.57×10^8m^3, and there is only 33.13×10^8m^3available for social and economics,but there would be a need of 33.44×10^8and 36.06×10^8m^3, and the water shortage would be 1.31 ×10^8and 2.93 ×10^8m^3in 2020 and 2030 respectively. When P =75,the total water resource is 44.30×10^8m^3, there is only 29.39×10^8m^3water available for social and economics. However, there would be a need of 31.43 ×10^8and33.11×10^8m^3, and the water shortage would be 2.04×10^8and 3.72×10^8m^3in 2020 and 2030, respectively. [Conclusion] The problem of water shortage would be serious over the next 15 years, and the fragile ecosystem would be destroyed dramatically with the large-scale land reclamation against natural laws. Hence, the effective policies and measures should be taken timely to prohibit reclamation and to cope with ongoing water shortage, based on the water supply and demand estimation under the background of climate change.

Analysis of Water Resources Supply and Demand and Security of Water Resources Development in Irrigation Regions of the Middle Reaches of the Heihe River Basin, Northwest China

Based on the data for meteorology, hydrology, soil, planting, vegetation, and socio-economic development of the irrigation region in the middle reaches of the Heihe River basin, Northwest China, the model of balance of water supply and demand in the region was established, and the security of water resource was assessed, from which the results that the effects of unified management of water resources in the Heihe River basin between Gansu Province and Inner Mongolia on regional hydrology are significant with a decrease in water supply diverted from Heihe River and an increase in groundwater extracted. In addition, it was found that the groundwater level has been steadily decreasing due to over pumping and decrease in recharges. In present year （2003）, the volume of potential groundwater in the irrigation districts is far small because of the groundwater overdraft; even in the particular regions, there is no availability of groundwater resources for use. By 2003, water supply is not sufficient to meet the water demand in the different irrigation districts, the sustainable development and utilization of water resources are not secured, and the water supply crisis occurs in Pingchuan irrigation district. Achieving water security for the sustainable development of society, agriculture, economy, industry, and livelihoods while maintaining or improving the abilities of the management and planning of water resources, determining of the reasonable percentage between water supply and groundwater utilization and water saving in agricultural irrigation are taken into account. If this does not occur, it is feared that the present performance of water development and planning may further aggravate the problem of scarcities of water resources and further damage the fragile ecological system.

Spatial matching and flow in supply and demand of water provision services: A case study in Xiangjiang River Basin

Global climate change and increased human consumption have aggravated the uneven spatiotemporal distribution of watershed water resources, affecting the water provision supply and demand state. However, this problem has often been ignored. The present study used the Xiangjiang River basin(XRB) as the study area, and the Integrated Valuation of Ecosystem Services and Trade-offs(InVEST) model, demand quantification model,supply–demand ratio, and water flow formula were applied to explore the spatial heterogeneity, flow, and equilibrium between water supply and demand. The results demonstrated significant spatial heterogeneity in the upstream, midstream, and downstream regions.The areas of water shortage were mainly located the downstream of the Changsha–Zhuzhou–Xiangtan urban agglomeration, and the Hengyang basin was the most scarcity area. Affected by terrain gradients and human needs, water flow varied from-16.33 × 10^(8) m^(3) to 13.69 × 10^(8) m^(3)from the upstream to the downstream area, which provided a possibility to reduce spatial heterogeneity. In the future, measures such as strengthening water resource system control,sponge city construction, and dynamic monitoring technology should be taken to balance the supply and demand of water in different river sections of the basin. This study can provide references for regulating water resources allocation in different reaches of the basin.

Analysis on the situation and countermeasures of water resources supply and demand in the cities of small and medium-sized river basins along southeast coast of China-taking Xiamen City as an example

The small and medium-sized river basins along southeast coast of China hold comparatively abundant water resources.However,the rapid resources urbanization in recent years has produced a series of water problems such as deterioration of river water quality,water shortage and exacerbated floods,which have constrained urban economic development.By applying the principle of triple supply-demand equilibrium,this paper focuses on the estimation of levels of water supply and demand in 2030 at different guarantee probabilities,with a case study of Xiamen city.The results show that water shortage and inefficient utilization are main problems in the city,as the future water supply looks daunting,and a water shortage may hit nearly 2×10^(8)m^(3)in an extraordinarily dry year.Based on current water supply-demand gap and its trend,this paper proposes countermeasures and suggestions for developing and utilizing groundwater resources and improving the utilization rate of water resources,which can supply as a reference for other southeast middle-to-small-sized basin cities in terms of sustainable water resources and water environment protection.

A Simple Discussion on the Supply and Demand of Water Resources in the Western Region of China

We are accustomed to solve the problem of the water scarcity in the western region by the thought of increasing the effective supply of water to meet the needs of Go-west Campaign. After introducing the dynamic equilibrium principle on supply and demand in economy, we find that we should solve the problem of the water scarcity in the western region through reducing total demand to achieve the dynamic equilibrium of supply and demand. Finally water resources in the western region can be enlarged by an accumulated way.

Analysis on water supply and demand of North China Plain

A water supply model and a water demand model are developed to exercise resources budgets of the North China Plain with a planning horizon of the year 2030. The budgets indicate that the North China Plain would face serious water stress from 1993 to 2000, and water resources available in the region can not meet the needs of the socioeconomic development and environment from 2000 to 2030. The south/north Water transfer project is the only option to solve the emerging water crisis.

A Study on Water Demand Load Estimation by Using Unit of Living Water - Focused on Micro Water Supply Area in Daegu City

Water supply capability has been significantly reduced as water demand has been increased due to changes of the world's weather, causing the increase of drought frequency, and urbanization. In terms of water production, water can be secured by construction a dam or procuring substitute water. However, the study approaches in terms of management of water supply area to control the existing water efficiently. Therefore, water demand was estimated by buildings, by which water load of micro water supply area was calculated. As a result, the deviation of water demand for 1,357 micro water supply areas could be calculated while the alternatives to dissolve the spatial demand unbalance were suggested by two types. From the study, firstly, we could anticipate the total water supply demand from the total sum by filtration plants but it was not possible to anticipate the characteristics of distribution within urban areas. For this, the study attempted to anticipate the demand of each 250 thousands of buildings, comprehending the demand of micro areas. Secondly, based on the built results, we suggest the directions to dissolve the water demand unbalance between and among regions, which could be the foundation to suggest the concrete methodology in the future.

RESEARCH ON MUNICIPAL WATER DEMANDS FORECAST

Based on the changing law of municipal water demand,a trigonometric function model for short-term water demand forecast is established using the time-series analysis approach.The method for forecasting water demand during holidays and under unexpected events is also presented.Meanwhile,a computer software is developed.Through actual application,this method performs well and has high accuracy,so it can be applied to the daily operation of a water distribution system and lay a foundation for on-line optimal operation.

Jordan’s Water Resources: Increased Demand with Unreliable Supply

Jordan is a small county located in the Middle East. Jordan has borders with Saudi Arabia, Syria, Iraq, and Israel (Figure 1). Jordan was established in 1921 and has very limited natural resources. Jordan’s current (2008) population is 6.5 million. The country has a total land area of 750,000 km2, about one third (92,300 km2) of which is dry land while the other two thirds (329,000 km2) are irrigated land. Jordan is considered as a water poor country due to unreliable and shortages in the supply of water sector. This makes it very difficult to meet the required and steadily increasing demand. Impact of climate change adds a layer to the uncertainty on the supply side of Jordan’s water portfolio. This paper addresses the water supply challenges that Jordan faces and what has been accomplished to improve supply and/or reduce demand. Many projects were undertaken or planned by the Jordanian government to increase the water supply and improve its reliability. Completing the proposed projects will result in Jordan meeting its water demand [1]. Otherwise, the Jordanian Government implement some or all the proposed short term solutions as presented in this paper.

Synthetic Reconstruction of Water Demand Time Series for Real Time Demand Forecasting

The forecasting of the demand applied to water supply systems has been an important tool to realize time control. The use of the time series to do the forecasting of the demand is the main way that has been used by researchers. By this way, the need of a complete time demand series increases. This work presents two ways to reconstruct the water demand time series synthetically, using the Average Reconstruction Method and Fourier Method. Both the methods were considered interesting to do the synthetic reconstruction and able to complete the time series, but the Fourier Method showed better results and a better fitness to approximation of the water consumption pattern.

Impacts of Climate Change on Water and Agricultural Production in Ten Large River Basins in China

The overall goal of this paper is to examine impacts of climate change on water supply and demand balance and their consequences on agricultural production in ten river basins in China. To realize this goal, China Water Simulation Model （CWSM） is used to analyze three alternative climate scenarios （A1B, A2 and B2）. The results show that the impacts of climate change on water supply and demand balance differ largely among alternative scenarios. While significant impacts of climate change on water balance will occur under the A1B scenario, the impacts of climate change under the A2 and B2 scenarios will be marginal. Under the A1B scenario, the water shortage in the river basins located in the northern China will become more serious, particularly in Liaohe and Haihe river basins, but the other river basins in the southern China will improve their water balance situations. Despite larger impacts of climate change on water balance in the northern China, its impacts on total crops＇ production will be moderate if farmers would be able to reallocate water among crops and adjust irrigated and rainfed land. The paper concludes with some policy implications.

Problems for water resources development in typical small karst drainage basins and countermeasures

In karst area water deficit is one of the main factors constraining sustainable economic development. In 1979 the comprehensive karstic observational field station was set up in Houzhai drainage basin located,\ in Puding county of Guizhou Province, which can represent most of the small karst drainage basins on the dividing line of the Guizhou Plateau. Geomorphology, water resources and water chemistry were investigated and observed. Based on comparisons of water supply with water demand and analysis of the main problems in water exploitation and utilization. it is found out that the water deficiency was not directly caused by the scarcity of natural water resources. The true reason is the insufficient capacity of water supply caused by the dismatch of the water and soil water resources which can be dealt with by building more irrigation works. Some solutions such as to build scientific basis for water exploitation and utilization and sustainable economic development in karst drainage basins on dividing line of the Guizhou Plateau.

Water Resources Development and Water Utilization in the Gavkhuni River Basin, Iran

Analysis of water supplies and demand over the past 50 years in the Gavkhuni River Basin（GRB） indicate that despite large investments in water resources development the basin remains just as vulnerable to drought as it always has been. During the period of analysis two transbasin diversions and a storage reservoir have been constructed which have more or less doubled the annual supply to water to the basin. But with each water resource development extractive capacity for irrigation, urban and industrial use has increased by the same amount, so that all new water is allocated as soon as it is available. The most recent developments, since 1980, have actually increased vulnerability to drought because extractive capacity is greater than average flow into the basin. Whenever demand exceeds supply all water is extracted from the basin and the tail end dries up. During the past 50 years flows into the salt pan at the downstream end of the basin have been negligible for more than half the time. Prospects for the future are bleak because once the current phase of water resources development is completed no further water supplies are likely, but demand continues to rise at a steady rate. Ultimately agriculture will have to concede water to urban, industrial and environmental demands.

Spatial and Temporal Patterns of Supply and Demand Balance of Water Supply Services in the Dongjiang Lake Basin and Its Beneficiary Areas

Water-related ecosystem services is a hot topic in ecological research. Water supply services are crucial to regional water cycles and water quantity balance. The Dongjiang Lake basin is a national priority river basin in China where ecological compensation pilot programs concerning water resources and water supply services are top priorities for ecosystem service protection. We analyzed spatial and temporal patterns associated with generation and use of water supply services in the Dongjiang Lake basin using the In VEST model, socio-economic data and water resource data. We found that between 1995 and 2010, water yield in the Dongjiang Lake basin and its beneficiary areas increased before declining, varying 9350–12 400 m3 ha-1 y-1; average water yield peaked in 2000. The spatial distribution patterns of water yield during these years are similar, progressively decreasing from upstream to downstream with a remarkable reduction in surrounding areas of city clusters. Average water consumption of the basin and its beneficiary areas ranged from 2900–4450 m3 ha-1 y-1 between 1995 and 2010; the spatial distribution patterns of water consumption during these years are similar, dropping gradually from urban construction land to its surroundings with a stronger gradient between urban and rural areas. More water was consumed on both banks and surroundings of the lake. From 1995 to 2010, water supply fell short of demand for urban construction land and its proximity as well as areas along the lake. Water supply services were able to satisfy needs in other regions. The Changsha-Zhuzhou-Xiangtan city cluster suffers from the most strained water supply.

Household model of rainwater harvesting system in Mexican urban zones

This paper describes a household model of the rainwater harvesting system in residential development of Tlaquepaque Jalisco Mexico. Harvested rainwater is estimated for designing a rainwater catchment system which reflects the maximum water supply to a household.Based on the estimation of the harvested rainwater the total water demand is calculated in order to explore the possible uses of rainwater. Major components in the rainwater catchment system are as follows catchment area downspout roof drain pipe and first flush tank cistern infiltration well pumping station and filtering system and ultraviolet UV water treatment.The rainwater harvesting system is designed to operate as the part of the central water supply system.This paper exposes the process of design and construction and its cost.In this way it aims to establish a technical and conceptual reference which enables the citizens to design their rainwater systems and their construction. This model will produce an important experience that can help to improve the systems in a Mexican context.It can be also useful for the international community.

WaterCAD软件在供水系统管网平差中的应用

WaterCAD软件可对供水管网系统进行静态与动态模拟分析和设计,能够快速、便捷地为用户产生各种图表、曲线和报告。利用WaterCAD软件对寿光市城区供水管网进行平差计算,以不同颜色表示节点压力、节点流量、管段管径、管长、流速、流量等各项信息,使供水管网系统化、图形化和直观化。采用此软件,可以保障供水系统的安全,提高供水系统的自动化水平。

New Opportunity and Challenges on Integrated Water Supply and Water Demand Managements

在未来10年以及更长的一段时间,全球和中国的水资源管理面临着紧迫的挑战,这些挑战包括水管控、水与食物、水与自然、水与能源、水与健康以及与气候变化相适应的与水相关的跨国合作,所有这些都与区域和全球尺度水安全相关。为了应对这些挑战,无论在中国还是世界范围,水资源管理战略必须解决需水管理(WDM)和供水管理(WSM)这两个重要问题,以及需水管理和供水管理的联合管理问题。本文将站在一个全球高度上研讨这一紧迫问题。通过分析,建议如下:在地方一级进行关于供水和需水管理的知识转让和经验交流和实践;在国家一级制定完善促进供需水管理的指导方针,最终发展到流域和区域级别。由于大陆或次大陆存在很大的差异,具体的区域指导报告是必要的,其中包括:专门针对现有可利用水资源和水需求的评估(通过使用水文方法进行水资源的评估以及需水调查和预测);关于组织、机构、税收、培训和教育的供需水的联合管理,在全球范围起草一个联合国公约草案。并在联合国会议上强调跨国界流域管理和/或竞争用水情况下的管理和/或水匮乏的供水需水联合管理的重要性。参照上述列举的目标,这些目标可能侧重于4个方面:在地方和国家一级(短期)供水管理;在地方和国家一级(短期)需水管理;在国家一级(中期和长期)供水管理和需水管理联合管理:在国际/区域一级(中期和长期)供水管理和需水管理联合管理。