Matrices in Environmental Impact Assessment – 2

I covered the three most popular form of matrices in my previous post, namely, Simple Matrix, Leopold Matrix, and the Component Interaction Matrix.

However, each project has different necessities and around the world, different EIA teams have come up with specific assessment matrices that will best suit their project/their country. In this post, we’ll take a look at some of the other lesser known, but nevertheless, effective assessment matrices.

Modified Graded Matrix

This is another graded form of a matrix developed by Lohani and Than (1980). The weights used in this matrix were relative weights. Each activity is assigned a relative value based on its priority level in the developmental activity. The priority is determined with respect to the environmental aspect that the activity could be impacting.

For example, drilling for oil will have a higher priority value with respect to affecting the soil, than for affecting the air of the drill site.

The total values of all interactions is placed on the horizontal axis of the matrix.

This method is particularly helpful when it comes to identifying activities that have a higher potential for causing damage in the developmental site, in identifying the environmental aspects these activities will majorly affect and specify areas that need most attention.


Impact Summary Matrix

This is probably the most well rounded matrix method I have come across. This type of matrix can identify potential impact areas, specify mitigation measures and even list out the agencies that can aid in the mitigation of these impacts. Talk about information in a little space!

Basically, the matrix is a summary of the entire Scoping stage. It is useful in giving an overview of the study that has been conducted, but it does not give us a detailed analysis of the impacts and the extent of the predicted impacts. It is superficial. Nevertheless, it can be useful to distill the study, if the developmental project is too large.

Loran Matrix

Unlike the Leopold Matrix, which has 100 developmental activities and 88 impacts, the Loran matrix has 234 developmental activities and 27 impacts against which they are assessed. The rest of the process of scaling and grading is similar to a Leopold matrix. The added step in a Loran Matrix is the introduction of algorithm based computations. The scaled results of the Loran matrix are fed into algorithms that generate impact scores. This matrix then, gives us an insight into critical impact areas.

One the one hand, the matrix considers a wide range of developmental activities. This shows that the user acknowledges that even the smallest of developmental activities can show an impact in the environment. However, this also only takes into account 27 of the major impact areas.

At the end of the day, the choice of the matrix depends solely on the EIA team. From my study of these matrices, I’ve come to the conclusion that a combination of matrices is the best way to properly assess and display the potential impacts of a project on the project site.



Author: Saurab Babu

Usually found sitting with a good book, nibbling on a piece of dark chocolate. Always ready for a good story.

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