Post-development monitoring of mitigation:

Waterman's Thea Cox discusses the benefits of the long-term monitoring of mitigation measures recommended in environmental statements

The Environmental Impact Assessment (EIA) Directive (85/337/EEC) has been in force since 1985 and applies to a wide range of defined public and private projects. The initial Directive and its three subsequent amendments in 1997, 2003 and 2009 have since been codified by Directive 2011/92/EU.

Mitigation measures form a critical part of the environmental statement (ES) and can be influential in the decision whether to approve a planning application. The implementation of mitigation is often tied to a planning permission as part of the planning conditions. However, as the situation currently stands, neither the existing EIA Directive (2011/92/EU) nor the UK EIA Regulations (Town and Country Planning Environmental Impact Assessment Regulations 2011) include any requirement to follow up and monitor mitigation measures.

As a result, even where mitigation is conditioned and subsequently carried forward by the developer, there is no formal means of determining whether or not it has been effective at reducing adverse environmental impact. This brings to light the question as to whether EIA is being used to its full potential.

For example, ecological mitigation set out in an ES that may be controlled by a planning condition can often include habitat creation and enhancement features. However, without post-development monitoring of these features, how can the success of the implemented mitigation works be accurately gauged?

One of the most comprehensive examinations of the implementation and effectiveness of ecological mitigation measures in completed EIA developments to date (see Drayson and Thompson (2013) Journal of Environmental Management) reported evidence suggesting a low rate of success of habitat mitigation measures.

The research concluded that habitat measures that are critical to achieving no net loss of biodiversity should be subject to monitoring as a matter of course. Suggested improvements included:

  1. identification of the measures that would benefit from monitoring;
  2. condition or obligate an appropriate monitoring regime that will maximise benefits; and
  3. ensure that the audit and monitoring results are made publicly available and reviewed by the local planning authority (LPA), with appropriate enforcement action taken where necessary.

While these actions alone will not be sufficient to ensure the success of mitigation measures on their own they could help to expedite the UK’s progress in achieving its EU obligation to halt biodiversity loss by 2020.

A new requirement for ESs to commit to and report monitoring arrangements, where appropriate, would build a bank of evidence about the success, or otherwise, of proposed mitigation measures. This information would help determine the effectiveness of mitigation measures; crucial to reducing the significant impacts of a development on the environment. The dissemination of the lessons learned from activities, such as monitoring, to those undertaking EIAs on behalf of developers would be the main benefit. Meanwhile, it would also demonstrate a developer’s strong commitment to the environment, which is becoming increasingly important to companies on a commercial basis.

The financial and resourcing implications of undertaking mandatory monitoring would doubtless be a key consideration for developers, who would inevitably be responsible for it. Monitoring would also require a much longer term commitment from LPAs to ensure that it is being implemented. Currently, an LPA only has an obligation to ensure that any conditions set out in the decision notice are complied with. As indicated above, such conditions typically relate to the implementation of the mitigation measures and not to monitoring their effectiveness.

Despite there being time and cost implications associated with mandating the monitoring of mitigation, there are also clear advantages to consultants and developers alike and, ultimately, the environment.

As a result of a review process, on 26 October 2012, the European Commission adopted a proposal for a revised EIA Directive. The commission’s five-year report on the application and effectiveness of the EIA Directive (2009) stated that post-project monitoring is needed “to provide authorities a sound basis for knowledge of the development of real-world impacts” and “a yardstick for making more in-depth and experience-based assessments in later EIA procedures, and thereby influence the decisions of scoping procedures in the future”.

The lack of post-development monitoring has been raised as one of the key flaws of current EIA practice in the UK. The monitoring and follow-up reporting of significant adverse and beneficial effects has the potential to inform and vastly improve future EIA practice.


This article was written as a contribution to the EIA Quality Mark’s commitment to improving EIA practice.

Thea Cox is a graduate consultant at Waterman Energy, Environment and Design

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