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Environmental principles


Water-related activity should aim to enhance or to cause least detrimental effect on the natural environment and its health and life-giving properties

Water-related activities need to be planned and implemented with due regard for all their environmental implications. Programmes and projects requiring the disruption of water flows can reduce the productivity of aquatic ecosystems, necessitate resettlement of affected populations, and devastate fisheries and grazing land. Pollution degrades water supplies, increasing the costs of water treatment. In some countries, integrated river basin management may provide a solution for surface waters since it allows all competing interests to be taken into account for one water-defined environment.

The protection of aquifers from pollution and over-exploitation should be afforded particular attention as the effects are not visible and can thus be neglected. The use of fossil groundwater should be avoided.

Water resources management systems will need to take into account the implications of all development activities related to the environment. These include industrial and agricultural development leading to discharges that endanger downstream water quality; changes in land use, such as road construction; settlement and cultivation of floodplains and other riverine environments; and the impacts of freshwater use and pollution on estuaries and coastal zones. Water resources management objectives therefore have to be carefully balanced against other long- and short-term development objectives.

Every effort should be made to capitalise on better knowledge of the water environment derived from recent experience. Working with the environment rather than against it is the desirable strategy. Technical methods using local materials, and biological methods to control weeds and disease vectors, have environmental advantages and build on natural capacities for pollution control and regeneration.

The allocation and consumption of water for environmental purposes should be recognised and given appropriate emphasis

Programmes and projects for the development, management and use of water mostly entail modifications of the natural environment to improve the quality of human life. However, certain water-related activities, such as flood control and drainage schemes, have as part of their central purpose an environmental objective.

Maintenance of the natural water environment is also important both for its intrinsic value and for supporting life. For example, water has an ‘in-stream’ value for fish and for the support of aquatic eco-systems. Eco-systems in wetlands and coastal zones depend on a certain volume and quality of water for their sustainability. Rivers and wetlands also have important functions as wildlife reserves, navigation routes, and areas for recreation. They also help to support natural biodiversity. In order to plan water utilisation priorities, therefore, it must be recognised that areas such as wetlands “consume” large quantities of water through evaporation. All uses, consumptive and non-consumptive, have to be considered and not automatically regarded as inferior to human and economically productive uses.

Environmental change should be monitored so that improvements can be encouraged and detrimental impacts minimised

Appropriate systems to monitor environmental changes throughout a project cycle and beyond will be needed. Appropriate expertise is needed from the outset to ensure that environmental aspects are properly assessed. Care should be taken to adopt systems that allow flexibility of action since some environmental costs may have to be accepted to gain greater social and economic benefits. (See Part III.)

Emphasis on environmental considerations is particularly appropriate in water-stressed areas, where the environmental and other implications of using alternative sources of supply – surface as opposed to groundwater, for example – need to be assessed. The inextricable connections between land and water management need to be recognised; land use and soil quality have a major influence on water flow and water quality, and vice versa. Integrated resource management needs to be the over-riding macro-environmental consideration.


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