吐鲁番地区恢复坎儿井的必要性分析

吐鲁番地区干旱少雨,降水量远远低于蒸发量,独特的干旱气候和绿州经济特点决定了水资源开发、节约与合理刺用的必要性.通过对吐鲁番坎儿井的长期研究分析,可以看出坎儿井是吐鲁番人民的农田灌溉和日常生产生活的主要水源之一.因此应大力推进保护、管理、恢复、加固、发展坎儿井工程的建设,引起全社会人们的重视.     

内蒙古包头市黄河灌区工程节水量计算

采用渠道衬砌前后单位长度渗漏损失差值计算工程节水量的方法,对内蒙古包头市黄河灌区实施渠道衬砌后进行计算,灌区总节水量8 310.01万m3,其中镫口灌区节水量4 709.06万m3,民族团结灌区节水量3 600.95万m3。灌区渠系水利用系数由现状的0.58提高到0.749,农田灌溉水利用系数由现状的0.41提高到0.674。该方法旨在为全面实施用水总量控制、提高农田灌溉水有效利用系数提供借鉴。     

膜下滴灌棉田不同春灌淋洗定额压盐效果分析

随着节水灌溉技术的发展,新疆节水灌溉面积已达到178.53万hm2,其中膜下滴灌棉田面积达到59.133万hm2。滴灌棉田盐碱化是节水灌溉中产生的新问题,春灌是水利措施改良盐碱地的方法之一。通过对新疆巴州试验站膜下滴灌棉田的现场试验数据进行分析,得出合理的春灌淋洗定额,以减轻盐碱对土壤的影响。     

农民用水协会考核与评价体系的构建

农民用水协会是农村实施土地承包经营责任制后产生一种新型灌溉管理模式,笔者根据协会的工作性质和内容,从规范运行管理的角度出发,由管理机构、管理人员、管理制度、工程管理、用水管理、财务管理、档案管理和参与管理八个方面介绍了评价指标体系的构建。     

小型农田水利工程设计研究

以南阳市社旗县灌溉工程为例．通过对水文地质条件分析与对关键数据的计算,对灌区取水工程设计、管网布置、电力系统布置做了研究,得出了井深为80m,井距为220m,共需建385座,水泵采用200QJ-32—78／6的潜水泵,电缆采用挖沟直埋,其中沟底宽300mm,口宽700mm,沟深1000mm的结论,该设计可以满足项目的灌溉要求,可为类似工程设计提供参考。     

Redefining the Water Poverty Index

Abstract

The Water Poverty Index (WPI) of arid and semiarid climatic zones is redefined by introducing the contribution of rainfed agriculture into WPI calculations and by making the WPI equation account for diversities in climatic conditions within arid and semiarid zones and for recycled household water used in irrigation.     

Global Water Demand and Supply Projections

Abstract

This paper presents a modeling approach for projections of water demand and supply for domestic, industrial, livestock, and irrigation at the basin or country level in a global scope. Particular emphasis is put on simulating water availability for crops taking into account total renewable water, non-irrigation water demand, water supply infrastructure, and economic and environmental policies at the basin or country level. This paper focuses on concepts and methodology involved in the modeling exercise. Data assessment and results are presented in a companion paper (Rosegrant and Cai, 2002).     

Economic Benefits of Reservoirs in the Irrigated Agriculture

Abstract

In the Jordan Valley of Jordan, the demand for water and ability to control its location, timing, quality, and quantity are becoming critical. The competition for water between the urban and agricultural sectors is increasing. There is a general trend in Jordan to reduce water allocated for agricultural use. Increasing the price of irrigation water or restricting the planted areas of water consuming crops, such as bananas, has been implemented during the recent growing season. The main objective of this paper is to highlight the impact of optimal allocation of irrigation water by building storage capacity on the economy of Jordan Valley. A linear programming technique is used, and the main results show that for proper management of water storage capacity, the suggested cropping pattern would generate $88.2 million, whereas the actual cropping pattern generated $74.4 million. The optimal water demand schedule is distributed according to the needs of the planted crops, and water demand has been allocated in an efficient way. In addition, appropriate management of storage capacity has solved the problem of water scarcity during the summer months, when peak production takes place. Storage-transfer system between locations played a significant role in reallocating irrigation water through the storage system. This compensates to a high degree in keeping the agricultural production more stable in physical and monetary units.     

基于排队理论的渠道容量设计

在设计一个新的灌溉配水系统时，渠道容量是一个不易确定的参数，因为农场用户提出供水的时间和水量通常是不确定的，取决于季节、气候、农作物种类等因素。渠道容量对灌溉投资和服务质量有重要的影响。提出运用排队理论确定渠道容量的大小。依据该理论，服务系统需提供的容量取决于将要达到的服务水平，以及顾客到达时间和服务时间的平均密度和分布规律。将灌溉渠道容量比作排队系统的服务能力。研究了指数分配和非指数分配模型及10个连续的灌溉周期。计算实例显示，同传统的Clement方程相比，该方法的结果相当可信。     

Transforming River Basin Management in South Africa

Abstract

This paper analyzes the transformation of river basin management in South Africa by focusing on the political processes involved in the creation of new water management bodies and irrigation infrastructure in the Lower Komati sub-basin. Institutional reform is described and analyzed in terms of the collaboration theory of Gray (1985). Attention is paid to the absence of mutual collaboration in the water domain through the analysis of three phases that are characteristic of collaborative management: problem setting, direction setting, and structuring. The perceptions and strategies of stakeholders in the change process are informed by the skewed access to land and water, the protracted struggle for redress of historical inequities, the quest for autonomy in water management by commercial farmers, and large political power differentials. This has resulted in differential access to decision making and political influence and in the materialization of these skewed relations in water control technology. The reluctance of stakeholders to explicitly recognize their interdependence and the role of the state as the convener of the change process has hampered the emergence of a shared appreciation of the problems in the water domain. Despite efforts by government to move towards equitable and inclusive water management, little redress of past inequities has taken place, and the majority of small farmers are uninformed and excluded from the change process. This suggests that the proposed Catchment Management Agency will not be representative nor attain equitable water management unless a well-conceived redistribution of water entitlements and land rights is carried out as part of an encompassing program to strengthen political democracy.