Throughout history the fugitive nature of water has posed conceptual and practical challenges to lawmakers. The vital importance of water to human activity is such that most societies and cultures have sought to establish legal rules over its use and allocation. But its fluidity and constant renewal as part of the hydrologic cycle has necessarily limited the appropriateness of traditional legal approaches to natural resources such as the concept of ownership. Consequently in most jurisdictions legal rights to use water - water rights - have traditionally been linked to land tenure rights and in particular to land ownership rights. More specifically such rights have been conferred on the owners of land with direct physical access to a stream, river or other natural water source. Very often the only way to sell the right to use water was to sell the associated land right. Driven mainly by increased pressure on water resources, but also by other factors that are discussed in this paper, a number of countries have recently undertaken substantive water law reforms. In some places such reforms are part of a process that began a hundred or more years ago. Elsewhere they represent a radical re-ordering of the status quo. A ...

A joint publication of the United Nations Educational, Scientific and Cultural Organization (UNESCO) and the Food and Agriculture Organization of the United Nations (FAO). Despite the social, economic, environmental and political importance of groundwater, international law has paid relatively little attention to this resource. Groundwater represents about ninety-seven percent of the fresh water resources available, excluding the water locked in the polar ice. It serves the basic needs of more than one-half of the world's population and it is often the only source of water in arid and semi-arid countries. Improvements in pumping technology and growth in industry, agriculture, and global population are leading to ever increasing levels of use of this resource, and to growing reliance on it. Largely as a result of these phenomena, groundwater resources and the social, economic and environmental systems dependent on them have, over the last fifty years, come under pressure from over-abstraction and pollution, seriously threatening their sustainability. International law has so far only rarely taken account of groundwater. While surface water treaties abound, groundwater is either nominally included in the scope of these instruments, mainly if it is "related" to surface waters, or it is not mentioned at all. Only few legal instruments ...

The performance of many canal irrigation delivery systems is unsatisfactory in terms of: (i) water resources management; (ii) service to irrigated agriculture; and (iii) cost-effectiveness of infrastructure management. In recent years, participatory approaches and management transfer reforms have been promoted as part of the solution for more cost-effective and sustainable irrigation services. Large agency-managed systems have been turned over partially or completely to various types of management bodies. However, the results have usually been disappointing. Common findings have been: (i) the new management bodies are not up to the task; and (ii) these bodies have inherited dilapidated systems and severe financial constraints. This FAO Irrigation and Drainage Paper presents a step-by-step methodology for water engineering professionals, managers and practitioners involved in the modernization of medium-scale to large-scale canal irrigation systems from the perspective of improving performance of conjunctive water supplies for multiple stakeholders. While the focus is on canal operation, the scope concerns the modernization of management. The approach consists of a series of steps for diagnosing performance and mapping the way forward in order to improve the service to users and the cost-effectiveness of canal operation techniques. This paper presents a proposed comprehensive methodology for analysing canal operation modernization, which is based ...

Drainage of agricultural land is one of the most critical water management tools for the sustainability of productive cropping systems, as frequently this sustainability is extremely dependent on the control of waterlogging and soil salinization in the rootzone of most crops. On some agricultural lands, the natural drainage is sufficient to maintain high productivity. However, many others require improvements in surface and subsurface drainage in order to optimize land productivity, while maintaining the quality of soil resources. As time passes, drainage requirements may change because of changes in the general socio-economic conditions, such as input and output prices, and more intensive crop rotations. In rainfed and irrigated areas of the temperate zones (where waterlogging is the dominant problem in lands lacking natural drainage), proper drainage has improved soil aeration and land and rural road trafficability. Moreover, it has facilitated the lengthening of the potential crop growth period. In the irrigated lands of the arid and semi-arid regions (where salinity problems dominate), in addition to the benefits described above, subsurface drainage has been essential for controlling soil salinity and reducing the incidence of erratic crop yields. In the semi-humid and humid tropical regions, drainage development has been less than in the agroclimate ...