Basic overview of impact assessment has been provided from previous post. As you are probably aware, from the embrio of environmental impact assessment long time, as time runs, the implementation has evolved into something more social.
Initially, the environmental impact assessmet focuses only on pure science about environmental effect that may happen during the activities of certain project. This as explained before includes scoping, inventory, asssessment and evaluation. But as this concept was implemented continously at that time, suggestion, ideas had been developed so that the core idea of environmental impact assessment itsel has evolved into something that more social and culture.
In this case, assessment of socioeconomic has played an increasing role, includes assessing impacts on archaelogical and historical sites that have cultural significance and even towards environmental justice impacts, something that has not been touched at the beginning of this concept. Because of this, some people will say that impact assessment has moved into a “softer” science which later causing overlap with questions of ethics and values. As a result, an engineer must take care to differentiate between quantitatively measurable impacts and qualitative assessments that might be influenced by value judgements, although on some aspect this will even make impact assessment implementation become harder. Risk assessment has also become increasingly important in environmental assessment.
Environmental engineers are usually only dealing with the “hard” science and risk assessments while socioeconomic impacts are analyzed by economists. It must be noted that environmental assessment must be thorough, interdisciplinary and as quantitative as possible. It involves: scoping, inventory, assessment and evaluation. The scoping defines the scope and the frame of the assessment and this will involve public hearing. Inventory is a step gathering and collectig all information about environmental susceptible areas, including socioeconomically impacted areas.
Thirs stage is assessment, it is the process of estimating the impact of the alternatives for both cumulative impacts or the impacts of a “no action” alternative. And the last is evaluation to interpret the findings. This often is done concurrently with estimating impacts.