5. Mitigation, Compensation and Enhancement

Overview
Monitoring of mitigation/compensation
Reporting mitigation, compensation and enhancement

Overview

5.1 There is a growing body of opinion that new developments should deliver net ecological gain rather than simply being designed to achieve mere damage limitation. Therefore, right from the start, proponents of any scheme should incorporate, as part of the proposals for scheme design and implementation, measures that are required to deliver ecological enhancements as well as measures to:

avoid negative ecological impacts - especially those that could be significant;
reduce negative impacts that cannot be avoided; and
compensate for any remaining significant negative ecological impacts.

5.2 Wherever possible, enhancement and mitigation measures should be developed and incorporated into a project as part of the design process, as measures that are fully integrated into a project have a greater guarantee of delivery. The objective should always be to agree the identified measures with the proponent of a project so that they become part of the scheme that is subject to detailed assessment. A shopping list of 'proposed mitigation' at the end of an EcIA is of very little value as it requires the competent authority to enter into discussion with the proponent to agree what will be implemented. An EcIA is effectively meaningless if it provides an assessment of the significance of the residual impacts of a scheme based on the proposed mitigation measures being implemented even though these measures have not been agreed by the developer⁷².

5.3 Priority should be given to the avoidance of impacts at source, whether through the re-design of a project or by regulating the timing or location of activities. If it is not possible to avoid significant negative impacts, opportunities should be sought to reduce the impacts, ideally to the point that they are no longer significant. If this is not possible, but the scheme is permitted, compensation may be appropriate. This should be designed to meet specific ecological objectives that will deliver meaningful compensation for the negative impacts that are predicted. The objectives may include:

primary, high level objectives related to the reasons for compensation, gross area of compensation and overall quality of compensation; and
detailed objectives comprising specific ecological requirements for the habitat compensation scheme in terms of, for example, the number of birds and the habitats that they require.

5.4 However, compensation often carries a degree of uncertainty. Furthermore, even if it is effective, there may be a temporary or permanent loss of ecological value due to a time lag between damage occurring and the new habitat becoming fully functional.

5.5 Due to the uncertainty associated with the success of proposed mitigation (and particularly compensation) measures, evidence should be provided of the effectiveness of recommended mitigation, compensation and enhancement measures and to what extent their success can be guaranteed. If possible, information from similar projects should be used to support statements about the level of success that can be reasonably expected.

5.6 The uncertainty associated with a project will vary according to a number of factors, including the:

technical feasibility of what is proposed (e.g. experience of projects where the proposed mitigation has been employed or carried out);
overall quantity of what is proposed (e.g. is it large enough to be viable; is it of equivalent extent to that of lost habitat?);
overall quality of what is proposed (e.g. does it compare favourably with features lost and those whose loss or damage is to be compensated?);
level of commitment provided to achieve what is proposed (e.g. is there a realistic understanding of what resources and effort will be required to achieve predicted outcomes?); and
timescale over which predicted benefits are to be realised.

5.7 Mitigation should be presented in terms of the integrity or conservation status of the resources or features to which it applies. For example, mitigation may be designed to ensure that the status of a species population can be maintained following development (see Table 1).

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Monitoring of mitigation/compensation

5.8 If mitigation/compensation measures are part of planning conditions or obligations, the proponent has a requirement to implement them fully (see Chapter 6). These conditions or obligations may require the implementation of a monitoring programme and any remedial measures that are identified as being necessary. Where this is not the case, it is good practice to monitor the success of mitigation or compensation measures that are proposed as part of an EcIA, and to remedy the situation should any of the implemented measures fail (e.g. due to lack of management). An Environmental Action Plan (EAP) can be a useful means of drawing together mitigation, compensation, enhancement, management and monitoring proposals. Joint agreement of EAPs by proponents and consultees can strengthen their implementation. An EAP may be enforced by legal agreement.

5.9 Follow-up and monitoring is more likely to take place if it is built into legal agreements or planning conditions. Ideally, measurable objectives, which set the trigger thresholds for remedial management action, should be agreed by all of the ecologists involved in the EcIA process.

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Reporting mitigation, compensation and enhancement

5.10 It is often helpful to set out in an EcIA report how a project has evolved in response to ecological considerations and to indicate how mitigation that has been incorporated into the scheme design has enhanced ecological out comes. Some ecologists present the results of impact assessment 'with' and 'without' mitigation, so that the need for mitigation is clearly justified. However, where mitigation is fully integrated into the scheme and there is high confidence that it will be implemented and will deliver the desired outcomes, it may be appropriate simply to assess the significance of impacts of the mitigated project.

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