* A formal process to predict the environmental consequence of human development activities and to plan an appropriate measure to eliminate or reduce the adverse impacts and to augment positive impacts. * EIA is an attempt to identify measure and evaluate the environmental impacts of a course of actions. Here, actions mean any development, strategy which will change an existing system. * According to LGED, assessment of beneficial and adverse change in the environmental resources or values, resulting from any proposed project. Methods available for conducting EIA study are:
* Checklist method
* Matrix method
* Overlays method
* Network diagram method
* Baseline studies
* Mathematical modeling
* Simulation modeling
Matrix methods identify interactions between various project actions and environmental parameters and components. They incorporate a list of project activities with a checklist of environmental components that might be affected by these activities. A matrix of potential interactions is produced by combining these two lists (placing one on the vertical axis and the other on the horizontal axis). One of the earliest matrix methods was developed by Leopold et al. (1971). In a Leopold matrix and its variants, the columns of the matrix correspond to project actions (for example, flow alteration) while the rows represent environmental conditions (for example, water, temperature). The impact associated with the action columns and the environmental condition row is described in terms of its magnitude and significance. Most matrices were built for specific applications, although the Leopold Matrix itself is quite general. Matrices can be tailor-made to suit the needs of any project that is to be evaluated. They should preferably cover both the construction and the operation phases of the project, because sometimes, the former causes greater impacts than the latter. Simple matrices are useful: 1) early in EIA processes for scoping the assessment; 2) for identifying areas that require further research; and 3) for identifying interactions between project activities and specific environmental components. However, matrices also have their disadvantages: they tend to overly simplify impact pathways, they do not explicitly represent spatial or temporal considerations, and they do not adequately address synergistic impacts. Matrices require information about both the environmental components and project activities. The cells of the matrix are filled in using subjective (expert) judgment, or by using extensive data bases. There are two general types of matrices: 1) simple interaction matrices; and 2) significance or importance-rated matrices. Simple matrix methods simply identify the potential for interaction. Significance or importance-rated methods require either more extensive data bases or more experience to prepare. Values assigned to each cell in the matrix are based on scores or assigned ratings, not on measurement and experimentation. For example, the significance or importance of impact may be categorized (no impact, insignificant impact, significant impact, or uncertain). Alternatively, it may be assigned a numerical score (for example, 0 is no impact, 10 is maximum impact).
Table: An impact matrix
Matrix 1| Clearing Plants| Soil Leveling| Accesses and Roads to Yard| Industry Building| New Workers’ house Building| Port Widening and Arrangement for Docking Ships| Landscape Alteration| ilz| ilz| ilz| ilz| ilz| ilz|
Loss of Outspace Light| ilz| ilz| ilz| ilz| ilz| ilz| Changes in Soil Stability| ilz| ilz| -| -| -| -|
Changes in General Characteristics of Soil| ilz| ilz| ilz| ilz| -| ilz| Growth of Air Pollution| -| -| ilz| ibz| -| -|
Growth of Water Pollution| -| -| ilz| ilz| -| ilz|
Changes in Town and Country Layout| -| -| ilz| ilz| ilz| ilz| Loss of Visibility| -...