Cumulative impact assessment
Also called: CIA, Cumulative environmental impact assessment · Topic: Environment and Sustainable Development · NCERT: Beyond NCERT
Meaning
A cumulative impact assessment (CIA) studies the combined effect of many projects on one area, such as a river basin, a forest belt or a mining region. It covers past, present and planned future projects, and it does not judge each one alone. Small harms that look acceptable one at a time can add up to serious damage. For example, several dams on one river together can change its water flow, block silt, break up fish habitats and raise flood risk downstream. A CIA is meant to catch this total harm before more projects are approved.
Example
In the Brahmaputra basin, the Subansiri, Dibang and proposed Siang Upper Multipurpose projects all sit on rivers that feed the same system. China's large dam upstream on the Yarlung Tsangpo also affects that system. Each project has been studied on its own, but the Central Water Commission (CWC) once considered ordering a cumulative impact assessment for the basin in Assam. Such a study would show what all of these dams together do to Assam's floodplains, farmers and fishers.
Don't confuse with
- Environmental impact assessment (EIA): EIA checks one project's likely environmental and social impacts before it is approved. It is done under the EP Act 1986, through notifications in 1994 and 2006. A CIA looks at the combined effect of all projects in an area.
- Social impact assessment (SIA): SIA studies how one project affects people, for example through displacement, land loss and rehabilitation. It is required under the RFCTLARR Act 2013. A CIA is mainly about the total environmental load on a region.