All uses and characteristics of land and water within a drainage basin may affect water quality and flow, and hence have an impact on other uses downstream. It is, therefore, considered that natural resources authorities should use a holistic approach to their management, and as much as possible use drainage basins and/or important ecosystems such as wetlands as the natural units for land and water management.
A stream catchment is all lands enclosed by a continuous drainage divide of the hydrologic-surface and lying upslope from a specific point on the stream. In the case of closed-basin systems, the catchment is all lands draining to a lake.
The river basin or catchment provides many examples of how the functional and spatial necessities of water can form civilization. The history of organizing around water is the history of building community far more than the history of warfare. At the turn of the 20th century multi-purpose plans were proposed for the Nile and Tigris-Euphrates by Sir William Willocks and the US President stated that each river system is a single unit and should be treated as such. In the mid 1950's the UN Secretary General stated that river basin development is now recognised as an essential feature of economic development. The building of river basin and watershed organisations is a major part of what the practical work of water and security is all about. In modern time, it was the navigation needs that generated legal frameworks for cooperation: navigation lays the groundwork for a legal or administrative unity of the river basin in a situation of politically divided basins where waterways were the best means of communication.
In a catchment, besides water security for the inhabitants, water is involved also in providing both food security, since large amounts of water are consumed in local food production, and environmental security, linked to a whole set of water-related threats from droughts, floods, land degradation, bacterial diseases and toxic pollution, the latter threatening both human health and ecosystems. As a consequence, water has to be managed in such a way that attention can be paid to the water-related linkages between all three modes of human security. The situation will be rather different under humid as opposed to arid conditions. In the humid zone situation where water pollution is the dominant problem, upstream/ downstream problems are principally easier to solve – the issue is not one of a zero-sum character. In the arid zone, especially at high levels of water crowding (i.e. with many people polluting each flow unit of water), upstream societal priorities influence downstream opportunities. If water for agriculture is given priority, less will be available for downstream users. Similarly, low upstream priority to water pollution abatement will reduce water usability downstream. All uses and characteristics of land and water within a drainage basin may affect water quality and flow, and hence have an impact on other uses downstream. Natural resources authorities should use a holistic approach to their management, and as much as possible use drainage basins and/or important ecosystems such as wetlands as the natural units for land and water management.
This strategy features in the framework of Agenda 21 as formulated at UNCED (Rio de Janeiro, 1992), now coordinated by the United Nations Commission on Sustainable Development and implemented through national and local authorities. Agenda 21 recommends promoting integrated watershed development and alternative livelihood opportunities as part of an integrated approach to the planning and management of land resources. It also recommends promoting watershed management practices so as to prevent, control and reduce degradation of the marine environment.
Article 5(j) of the 1999 Draft Protocol on Water and Health to the 1992 Convention on the Protection and Use of Transboundary Watercourses and International Lakes, states: Water resources should, as far as possible, be managed in an integrated manner on the basis of catchment areas, with the aims of linking social and economic development to the protection of natural ecosystems and of relating water-resource management to regulatory measures concerning other environmental mediums. Such an integrated approach should apply across the whole of a catchment area, whether transboundary or not, including its associated coastal waters, the whole of a groundwater aquifer or the relevant parts of such a catchment area or groundwater aquifer.
The International Conference on Water and the Environment (Dublin, January 1992) recommended that for water policies to be effective, the most appropriate entity on which to plan is the river basin, including surface and groundwater.
Recognized water management policies and trends include: (a) the reaffirmation of the importance of drinking-water supply and sanitation for human health; (b) an emphasis on holistic approaches requiring intersectoral coordination, reconciliation of competing uses and catchment-level management; (c) recognition of the importance of securing stakeholder participation and providing a role for nongovernmental organizations and civil society; (d) an emphasis on the need to protect and conserve the aquatic environment upon which multiple beneficial uses depend; and (e) the call for increased international cooperation and coordination.
The Government of Manitoba, Canada, has established a Land and Water Strategy to enable them to manage their water resources in a sustainable manner. The Strategy is based on the following objectives: (a) to sustain and enhance resource productivity and improve the environmental quality of Manitoba; and (b) to improve and diversify income and job opportunities. Issues covered include: water quality, conservation, use and allocation, water management infrastructure, flooding and drainage.
The key to watershed health is to coordinate and link up natural resources stewardship and polluted runoff prevention strategies throughout the watershed, protecting those portions of the watershed that remain pristine while, at the same time, minimizing those sources of polluted runoff causing the greatest harm.