Starting up; early stages - Introduction to Environmental Impact Assessment - page 119

Alternative sites

Site A Site B Site C

Environmental component (a)

(c) (a×c) (c) (axc) (c) (a×c)

Air quality 21 3 63 5 105 3 63

Water quality 42 6 252 2 84 5 210

Noise 9 5 45 7 63 9 81

Ecosystem 28 5 140 4 112 3 84

Total 100 500 364 438

(a) = relative weighting of environmental component (total 100)
(c) = impact of project at particular site on environmental component (0-10)

Figure 4.13 A weighted matrix:
alternative project sites.

Distributional impact matrices represent another possible development of the matrix
approach. Such matrices can broadly identify who might lose and who might gain from
the potential impacts of a development. This is useful information, which is rarely
included in the matrix approach, and indeed is often missing from EISs. Impacts can have
varying spatial impacts—varying, for example, between urban and rural areas. Spatial
variations may be particularly marked for a linear project, such as a Light Rapid Transit
system. A project can also have different impacts on different groups in society (for
example the impacts of a proposed new settlement on old people, retired with their own
houses, and young people, perhaps with children, seeking affordable housing and a way
into the housing market) (see Figure 5.7, Chapter 5).