Leopold matrix

The Leopold matrix is a qualitative environmental impact assessment method developed in 1971 by Luna Leopold and collaborators for the USGS.^[1] It is used to identify and assign numerical weightings to potential environmental impacts of proposed projects on the environment.^[1] It came as a response to the National Environmental Policy Act of 1969 which was criticized for lacking adequate guidance for government agencies on how to properly predict potential environmental impacts and consequently prepare impact reports.^[1]

An Example Showing the Location of Magnitude and Importance Values in a Leopold Matrix Cell

The system consists of a grid of 100 rows representing the possible project activities on the horizontal axis and 88 columns representing environmental factors on the vertical axis, for a total of 8800 possible interactions.^[1] In practice, only a select few (25-50) of these interactions are likely to be of sufficient importance to be thoroughly considered.^[1] Where an impact is expected, the appropriate cell of the matrix is split diagonally from the top right corner to the bottom left corner in order for the magnitude and importance of each interaction to be recorded.^[2] The magnitude (from -10 to +10) is inserted on the top-left diagonal and the importance (from 1 to 10) is inserted on the bottom-right diagonal.^[1] Measurements of magnitude and importance tend to be related, but do not necessarily directly correlate. Magnitude can be measured more tangibly in terms of how much area is affected by the development or how severely, however, the importance is a more subjective measurement. While a proposed development may have a large impact in terms of magnitude, the effects it causes may not actually significantly affect the environment as a whole. The example given by author Luna Leopold is of a stream that significantly alters the erosion patterns in a specific area, which may be scored highly in terms of magnitude but may not be necessarily significant, provided the stream in question is swift-moving and transports large amounts of sediment regardless.^[1] In this case, an impact of significant magnitude may not actually be important to the environment in question.

Strengths

As outlined by the original authors, the matrix provides a structured framework for practitioners of environmental impact assessment to systematically rank potential significant environmental cause-and-effect relationships.^[1] A structured approach avoids the downsides of less organized ad hoc approaches to impact prediction in which impacts can be either underestimated or completely overlooked.^[3] Additionally, the grid format allows for a visual display of results that can be easily understood by policymakers and the public.^[4][5] The matrix is also capable of expanding and contracting based on the scope and environmental context of any given undertaking, rendering it functional for both large and small-scale projects.^[2] Finally, it is beneficial to practitioners that the tool can be applied at various temporal stages of the environmental impact assessment process.^[6]

Criticisms

One of the fundamental downfalls of the method is the lack of criteria or standard methods for assigning magnitude and significance values which may lead to subjective judgements.^[7][8][9] In the same vein, the method has also been identified as lacking the ability to facilitate any degree of public involvement, primarily due to the subjective value judgements of the user.^[10] Another potential pitfall is the sheer size of the matrix with a total of 17 600 items of information potentially being analyzed.^[11][12] The size of the matrix has also been criticized as being too detailed for some projects while simultaneously being too imprecise for others.^[13] In terms of direct content, the chance of double-counting certain impacts is also present.^[14][15] The matrix has further been identified as being highly biased toward biophysical impacts making the social impacts of a given project difficult to assess.^[6][16] Of the impacts that are covered, the matrix is seldom capable of taking into consideration secondary or cumulative impacts which are often significant considerations in environmental impact assessment.^[17][18][19] Another area that the method can be deficient in is having a mechanism capable of distinguishing between long-term impacts and short-term impacts.^[20][21][22] Due to the presentation of completed matrices, the method has also been identified as treating interactions as though they are certain to occur, with no consideration of probability.^[17]

Examples of Leopold Matrix Implementation

• Gonabad landfill; a study conducted to evaluate the environmental effects of a municipal waste landfill site.^[23]
• Vojvodina ecological network; an assessment of the influences of anthropogenic factors on an ecological network (salt steppes, marshes, etc.).^[24]
• Karbala water projects; a study on seven drinking water treatment facilities based on physio-chemical properties.^[25]
• Binh Thuan desertification; an assessment of the potential desertification effects and subsequent impacts on socio-economic conditions and water availability.^[26]

See also

• Environmental Impact Assessment – Assessment of the environmental consequences of a decision before action
• Strategic Environmental Assessment
• Social Impact Assessment – Reviews infrastructure and development
• Impact Assessment – formal, evidence-based procedures that assess the economic, social, and environmental effects of public policyPages displaying wikidata descriptions as a fallback
• Risk assessment – Estimation of risk associated with exposure to a given set of hazards
• Precautionary Principle – Risk management strategy
• International Association for Impact Assessment – International organization
• Healthy development measurement tool – Evaluates impact of urban development

References

1. Leopold, Luna Bergere; Clarke, Frank Eldridge; Hanshaw, Bruce B.; Balsley, James R. (1971). "A Procedure for Evaluating Environmental Impact". Circular. Washington, D.C. p. 19. doi:10.3133/cir645 – via U.S. Geological Survey.
2. Noble, Bram F. (2020). Introduction to environmental assessment : a guide to principles and practice (4 ed.). Don Mills, Ontario: Oxford University Press. ISBN 978-0-19-902889-4. OCLC 1153262303.
3. Bank, Asian Development (1997-12-01). Environmental Impact Assessment for Developing Countries in Asia. Asian Development Bank.
4. Kumar A. Rathi, Arjun (2021). Handbook of Environmental Impact Assessment : Concepts and Practice. Newcastle-upon-Tyne. ISBN 978-1-5275-6789-4. OCLC 1246578449.
5. Carley, Michael (2019). Social impact assessment and monitoring : a guide to the literature. Eduardo S. Bustelo. London: Routledge. ISBN 978-0-429-30630-3. OCLC 1102806782.
6. Mareddy, Anji Reddy (2017). Environmental impact assessment : theory and practice. Kidlington, Oxford. ISBN 978-0-12-811238-0. OCLC 990802553.
7. Methods of environmental impact assessment. Peter Morris, Riki Therivel (3 ed.). London: Routledge. 2009. ISBN 978-0-203-89290-9. OCLC 319298237.
8. Rogers, Peter P. (2008). An introduction to sustainable development. Kazi F. Jalal, John A. Boyd. London: Earthscan. ISBN 978-1-84977-047-7. OCLC 185040378.
9. Mushtaq, Basharat (2020). Environmental management environmental issues, awareness and abatement. Suhaib A. Bandh, Sana Shafi. Singapore: Springer. ISBN 978-981-15-3813-1. OCLC 1154563861.
10. J., Barrow, Christopher (2000). Social impact assessment : an introduction. Arnold. ISBN 0-340-74217-8. OCLC 45860278.
11. Clark, Brian D; Chapman, Keith; Bisset, Ronald; Wathern, Peter (1978). "Methods of Environmental Impact Analysis". Built Environment (1978-). 4 (2): 111–121. ISSN 0263-7960. JSTOR 23284628.
12. Wood, Christopher (2000), "Screening and Scoping", Environmental Assessment in Developing and Transitional Countries, John Wiley & Sons, Ltd, pp. 71–84, doi:10.1002/9781118685570.ch4, ISBN 978-1-118-68557-0
13. Environmental impact assessment and environmental auditing in the pulp and paper industry. Oreade, Food and Agriculture Organization of the United Nations. Forest Products Division. Rome: Food and Agriculture Organization of the United Nations. 1996. ISBN 92-5-103794-9. OCLC 38294546.
14. Bhatnagar, K. C. (2009). Environmental management : new directions for the 21st century. New Delhi: Global India Publications. ISBN 978-93-80228-11-2. OCLC 435376013.
15. Graham Smith, L (2014). Impact Assessment and Sustainable Resource Management. Taylor & Francis. ISBN 9781317900108.
16. MacKinnon, Aaron J. (2018). The application of science in environmental impact assessment. Peter N. Duinker, Tony R. Walker. Milton Park, Abingdon, Oxon. ISBN 978-1-351-17344-5. OCLC 1020318892.
17. Glasson, John (2005). Introduction to environmental impact assessment. Riki Therivel, Andrew Chadwick (3 ed.). London: Routledge. ISBN 0-415-33836-0. OCLC 60559255.
18. Hira, Anil (2004). Development projects for a new millennium. Trevor W. Parfitt. Westport, Conn.: Praeger. ISBN 0-275-97502-9. OCLC 52216286.
19. Planning and design of engineering systems. G. C. Dandy (2 ed.). [Place of publication not identified]. 2018. ISBN 978-1-351-99129-2. OCLC 1051352223.
20. Kassim, Tarek A.; Simoneit, Bernd R. T. (2005), Kassim, Tarek A.; Williamson, Kenneth J. (eds.), "Environmental Impact Assessment: Principles, Methodology and Conceptual Framework", Water Pollution, vol. 1, Berlin/Heidelberg: Springer-Verlag, pp. 1–57, doi:10.1007/b98263, ISBN 978-3-540-00268-0, retrieved 2021-11-15
21. Environmental management : issues and concerns in Developing Countries. Pradip K. Sikdar. Cham. 2021. ISBN 978-3-030-62529-0. OCLC 1242466181.
22. Eccleston, Charles H. (2008). NEPA and environmental planning : tools, techniques and approaches for practitioners. CRC Press. Boca Raton: CRC Press. ISBN 978-1-4200-0781-7. OCLC 311307339.
23. SA, Sajjadi (2017). "Environmental impact assessment of Gonabad municipal waste landfill site using Leopold Matrix". Electronic Physician. 9 (2): 3714–3719. doi:10.19082/3714. PMC 5410896. PMID 28465797.
24. Kicošev, Vesna; Romelić, Jovan; Belić, Anđelka; Marinić, Ivo; Panjković, Biljana (2015). "Assessment of the influence of anthropogenic factors on elements of the ecological network in Vojvodina (Serbia) using the Leopold matrix". Archives of Biological Sciences. 67 (4): 1209–1217. doi:10.2298/abs150303097k.
25. Al-Nasrawi, F A; Kareem, S L; Saleh, L A (2020-01-17). "Using the Leopold Matrix Procedure to Assess the Environmental Impact of Pollution from Drinking Water Projects in Karbala City, Iraq". IOP Conference Series: Materials Science and Engineering. 671 (1): 012078. Bibcode:2020MS&E..671a2078A. doi:10.1088/1757-899X/671/1/012078. ISSN 1757-899X. S2CID 213207854.
26. Hai, Le Trinh; Gobin, Anne; Hens, Luc (2014-01-02). "Uncovering causes and effects of desertification using a Leopold matrix in Binh Thuan Province, Vietnam". Chinese Journal of Population Resources and Environment. 12 (1): 57–67. Bibcode:2014CJPRE..12...57H. doi:10.1080/10042857.2014.883052. ISSN 1004-2857. S2CID 128966076.