【文章內(nèi)容簡介】 lem. The planners suggested a range of innovative solutions to this problem: ? improved recreational provision at existing open spaces ? rooftop terraces on top of new and existing buildings ? use of the waterfront along adjacent River Y as recreational space ? increased use of River Y for boating, surfing etc. The SEA showed that existing open spaces and the waterfront could only acmodate a limited amount of additional use。 that rooftop terraces were in the private realm and not publicly accessible。 and that use of River Y for recreation required a financial outlay (rental or purchase of boat etc.) that many residents of X would not be able to afford. The final plan also included requirements for new developments to be acpanied by provision of free, publicly accessible open space: hectares for every 1000 new residents. Outes of SEA 5. Identify mitigation measures to minimise or avoid negative impacts. For instance, for a regional plan in an area where water abstraction already exceeds water supply, a mitigation could be: ? Require all new developments of 10 or more houses to be 39。water neutral39。: total water use in the region after the development must be less than or equal to total water use in the region before the development. For developments of less than 10 houses, water efficiencies of 40% over existing levels must be achieved. For a local plan that could affect the habitat of a rare bat, a mitigation could be: ? Until more information exists on the foraging habits of the Barbastelle bats at Site Z is available, any development that could affect any trees, hedges or water bodies within 6km of the boundary of Site Z should require assessment to ensure that Barbastelle bat foraging grounds are not negatively affected. If more detailed information bees available (. if a bat foraging survey is carried out) then this could reduce the need for project level assessment. The examples above show some typically used SEA techniques: ? maps to describe the baseline environment, identify problems, and predict impacts ? matrices that test alternatives or subsections of the strategic action against environmental/sustainability criteria ? use of red/amber/green (traffic light colours) to allow key impacts to be easily identified ? qualitative, +/, 39。expert judgement39。 type of appraisal where detailed, quantitative assessment is not possible The last example also represents two typical SEA principles: ? Tiering. In this case, in the absence of full information at the plan level, projectlevel mitigation measures are used. ? The precautionary principle: where there is uncertainty about the impacts of a strategic action, one should assume that negative impacts will occur, and mitigate for them, unless/until one can show that these impacts are unlikely to occur. In this case, all trees and hedges are to be protected until studies show that some of them don39。t need to be. ? EIA of Projects SEA of policies, plans and programmes Takes place near the end of decisionmaking cycle: aims to minimise impacts Takes place at earlier stages of decisionmaking cycle: aims to prevent impacts Reactive approach to development proposal Proactive approach to development proposals Considers limited number of feasible alternatives Considers broad range of potential alternatives Limited review of cumulative effects Cumulative effects assessment is key to SEA Emphasis on mitigating and minimizing impacts Emphasis on meeting environmental objectives, maintaining natural systems Narrow perspective, high level of detail Broad perspective, lower level of detail to provide a vision and overall framework Welldefined process, clear beginning and end Multistage process, overlapping ponents, policy level is continuing, iterative Focuses on standard agenda, treats systems of environmental deterioration Focuses on sustainability agenda, gets at sources of environmental deterioration SEA addresses the limitations of project EIA ? Because EIA takes place once many strategic decisions have already been made, it can often address only a limited range of alternatives and mitigation measures: those of a wider nature are generally poorly integrated into project planning. ? Consultation in EIA is also limited and the contribution of EIA to the eventual decision regarding the project is unclear. Although project EIA is widely used and accepted as a useful tool in decisionmaking, it largely reacts to development proposals rather than proactively anticipating them: At this [EIA] stage, the prior questions of whether, where and what type of development should take place are either decided or largely preempted by earlier policy making processes. Often, these decisions will have occurred with little or no environmental analysis. This foreclosure