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C2.6 Environmental Assessment (EA)


Environmental Assessment (EA) is a tool for anticipating the environmental effects of policy changes and new developments, enabling the incorporation of management or control measures into project and policy design. It is routinely used all around the world to improve the planning of projects and is increasingly being used to examine strategies, policies, plans, and sector programmes, when it is known as Strategic Environmental Impact Assessment (SEIA) or Strategic Environmental Assessment (SEA). EA is required when projects are likely to have significant effects on the environment. Criteria for deciding whether IWRM projects should be subject to EA include:

  • The size or scale of the project (e.g. described by design capacities);
  • The sensitivity of the affected area (e.g. wetlands ,wildlife habitats and biodiversity);
  • The character or complexity of the likely impacts (e.g. physical impacts from hazardous wastes or social impacts (see C2.7), for instance in resettlement schemes).

The basic methodology of EA is to study the environment in which a project is planned (the baseline), describe the activities that will take place during each phase of a project (i.e. the construction, operation and decommissioning), describe the likely environmental impacts and, where significant adverse impacts are predicted, develop an Environmental Management Plan (EMP) to mitigate them. A programme to monitor changes from project impacts in environmental parameters forms part of the EMP.

Impacts of particular importance in many IWRM projects are:

  • Projected quantitative changes in availability of water for beneficial uses, such as fisheries, recreation and tourism, potable water supply, irrigation and industrial use;
  • The extent to which water quality standards and/or other beneficial use objectives will be achieved;
  • The length of stream or expanse of lake or coastal waters that will be positively or negatively affected by any discharges, and the magnitude of the changes in water quality parameters;
  • Public health impacts from chemical or bacteriological pollution;
  • Socio-economic impacts (see C2.7 Social Assessment).

Lessons learned

  • The best results are often reached when EAs of progressive levels of detailing are mainstreamed in the planning, design and implementation process allowing early consideration of alternative schemes and adjustment of project designs at times when most flexibility exists. Once the design and siting of a development are complete, any further mitigation of environmental effects will rely on end-of-pipe adjustments or compensation provisions, and these are usually the most costly and the least effective environmental management options.
  • EA facilitates public consultation by providing a context in which the public can both learn about and express opinions on development proposals and their envisaged effects. People potentially affected by the project can exert influence to reduce adverse impacts, maximise ancillary benefits and ensure that they receive appropriate compensation.
  • EA allows the authority involved to make better decisions, such that environmental (and social) costs and benefits are considered alongside the technical and financial costs and benefits. Conditions that ensure the most efficient use of resources can appropriately be incorporated into the EMP.

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