Impact prediction, evaluation and mitigation - Introduction to Environmental Impact Assessment - page 157

5.4.1 Types of mitigation measures

Mitigation is defined in EC Directive 97/11 as “measures envisaged in order to avoid,
reduce and, if possible, remedy significant adverse effects” (CEC 1997). In similar vein,
the US CEQ, in its regulations implementing the NEPA, defines mitigation as including:
“not taking certain actions; limiting the proposed action and its implementation;
repairing, rehabilitating, or restoring the affected environment; presentation and
maintenance actions during the life of the action; and replacing or providing substitute
resources or environments” (CEQ 1978). The guidance on mitigation measures provided
by the UK government is set out in Table 5.10. It is not possible to specify here all the
types of mitigation measures that could be used. Instead, the following text provides a
few examples, relating to biophysical and socioeconomic impacts. The reader is also
referred to Fortlage (1990), Morris & Therivel (2001) and Rodriguez-Bachiller with
Glasson (2003) for useful coverage of mitigation measures for particular impact types. A
review of EISs for developments similar to the development under consideration may
also suggest useful mitigation measures.
At one extreme, the prediction and evaluation of impacts may reveal an array of
impacts with such significant adverse effects that the only effective mitigation measure
may be to abandon the proposal altogether. A less draconian, and more normal, situation
would be to modify aspects of the development action to avoid various impacts.
Examples of methods to avoid impacts include:

• the control of solid and liquid wastes by recycling on site or by removing them from the
site for environmentally sensitive treatment elsewhere;

Table 5.10 Mitigation measures, as outlined in UK
guide to procedures

Where significant adverse effects are identified, [describe] the measures to be taken to avoid,
reduce or remedy those effects, e.g.:
(a) Site planning

(b) Technical measures, e.g.:

(i) process selection

(ii) recycling

(iii) pollution control and treatment

(iv) containment (e.g. bunding of storage vessels)

(c) Aesthetic and ecological measures, e.g.:

(i) mounding

(ii) design, colour, etc.

(iii) landscaping

(iv) tree plantings