Mitigation hierarchy is a concept developed to allow infrastructure projects with potential to damage environmentally sensitive areas to plan and implement measures to avoid, minimize, mitigate or offset impacto.

1. Avoid: This measure is based on the prevention of impacts so they do not occur or do not negatively affect environmentally sensitive areas.
2. Minimize: This measure intends to reduce duration, intensity, and extension of impacto.
3. Restore: This measure is focused on bringing back affected areas to their initial conditions.
4. Offset: When previous mitigation actions have been effectively implemented, the residual impact could be managed through an offset measure.

For more information:

http://www.thebiodiversityconsultancy.com/approaches/mitigation-hierarchy/

http://bbop.forest-trends.org/pages/mitigation_hierarchy