Leopold Matrix: Environmental Impact Assessment-Magnitude & Importance YouTube Lecture Handouts

Get top class preparation for competitive exams right from your home: get questions, notes, tests, video lectures and more- for all subjects of your exam.

Leopold Matrix: Environmental Impact Assessment - Magnitude & Importance |EIA|Environmental Sciences

Title: Leopold Matrix

What is Leopold Matrix?

  • The Leopold matrix is the best-known matrix methodology available for predicting the impact of a project on the environment.
  • The analysis is performed with the Leopold Matrix (LM) (Leopold et al. , 1971) . This matrix has: (1) on the horizontal axis, the actions which cause environmental impact, and (2) on the vertical axis, the existing environmental conditions which may be affected by those actions. This provides a format for comprehensive review of the interactions between proposed anthropogenic actions and environmental factors.
  • The number of actions listed on the horizontal axis is 100. The number of environmental factors listed on the vertical axis is 88. This provides a total of 8,800 interactions. In practice, however, only a few of the interactions would be likely to involve impacts of such magnitude and importance to warrant detailed treatment.
  • Not all the actions and factors apply to every project proposal; in some cases, other actions and factors not considered here may be warranted. According to Leopold et al. (1971) , the number of interactions for a typical project is between 25 and 50.
  • The example given by author Luna Leopold is of a stream that significantly alters the erosion patterns in a specific area, which will have a significant magnitude, but may not be important, provided the stream in question is swift moving and transports large amounts of soil anyway. In this case, an impact of significant magnitude may not actually be important to the environment in question

Importance of Leopold Matrix

Importance of Leopold Matrix
  • The Leopold matrix provides a simple way to summarize and rank environmental impacts, and to focus on those that are considered to be greatest. The advantage of the matrix format is its reminder of the full range of actions, factors, and related impacts.
  • As far as possible, the assignment of magnitude is based on factual information. However, the assignment of importance may leave some room for the subjective opinion of the evaluator. This separation of fact from opinion is an asset of the Leopold matrix.

Reading a Matrix

Reading a Matrix
  • It is a two-dimensional matrix cross-referencing:
    • the activities linked to the project that are supposed to have an impact on man and the environment.
    • the existing environmental and social conditions that could possibly be affected by the project.
  • The activities linked to the project are listed on one axis: raw material production, building construction, water supply, energy supply, raw material preparation, pulp and paper mills processing, gaseous emissions, liquid effluents, cooling water discharges, noise, solid wastes treatment and disposal, transportation.
  • The environmental and social conditions are listed on the other axis, and divided in three major groups:
    • physical conditions: soil, water, air … ,
    • biological conditions: fauna, flora, ecosystems … ,
    • social and cultural conditions: land use, historical and cultural issues, populations, economy …

3 Step Process to Estimate Project

3 Step Process to Estimate Project
  • The Leopold matrix proposes a three-step process to estimate the impact:
    • for all the interactions considered significant by the authors, the first step is to mark the corresponding boxes in the matrix with a diagonal line.
    • once the boxes with supposed significant interactions are slashed, the author evaluates each box by applying a number from 1 to 10 (1 is the minimum and 10 the maximum) to register the magnitude of the interaction. This number is transferred to the upper left-hand corner. It represents the scale of the action and its theoretical extent.
  • the final step for this method is to mark (from 1 to 10) , in the lower right-hand corner, the real importance of the phenomenon for the given project. It then gives an evaluation of the extent of the environmental impact according to the assessor՚s judgement
  • The activities linked to the project are listed on one axis: raw material production, building construction, water supply, energy supply, raw material preparation, pulp and paper mills processing, gaseous emissions, liquid effluents, cooling water discharges, noise, solid wastes treatment and disposal, transportation.
  • The environmental and social conditions are listed on the other axis, and divided in three major groups:
    • physical conditions: soil, water, air … ,
    • biological conditions: fauna, flora, ecosystems … ,
    • social and cultural conditions: land use, historical and cultural issues, populations, economy …
  • Within the square top side is magnitude (if high – strong impact) and bottom side is importance/significance (if low – perhaps locally contained)
  • 1 is low
  • 10 is high
  • + is positive impact
  • Is negative impact

Developed by: