LAMBAYEQUE, PERU TASK 4: METHODOLOGY FOR ENVIRONMENTAL IMPACT ASSESSMENT February 06, 2009
Dr. Victor M. Ponce
Environmental Consultant
1. INTRODUCTION
D'Leon Consulting Engineers, of Long Beach, California, hereafter referred to as DLCE,
has a contract with the Regional Government of Lambayeque, Peru, hereafter RGL,
to support the development of the La Leche River flood control project.
The study aims to enhance flood control and water conservation in the watershed of the La Leche river, which has
suffered major floods caused by the El Niño phenomenon.
The funding agency is the U.S. Trade and Development Agency (UST&DA).
The local government agency in charge of the project is the Proyecto Especial Olmos-Tinajones, hereafter PEOT.
Dr. Victor M. Ponce, hereafter the Consultant, has a subcontract with DLCE
to perform the environmental impact assessment (EIA) component of the study.
This preliminary report is submitted in partial fulfillment of the requirements of the contract between the Consultant and DLCE.
The report describes the Consultant's accomplishments in
fulfillment of Task 4: Environmental Impact Assessment Methodology, of the contract between RGL and DLCE.
2. NEED FOR ENVIRONMENTAL IMPACT ASSESSMENT
The United States government requires an environmental impact assessment (EIA) of a development project prior to authorization for funding.
This requirement is rooted in the Environmental Policy Act of 1969.
For nearly four decades, societies around the world have been
requiring an assessment of environmental impact.
The Inter-American Development Bank (IADB), a major source of development funds in Latin America,
requires that all environmental impacts be quantified and included in the economic analysis.
To comply with this requirement, the contract between RGL and DLCE contains two tasks:
Task 4, "Environmental Impact Assessment Methodology,"
and Task 5, "Environmental Impact Assessment Report."
The objective of Task 4 (this report) is to identify the appropriate EIA methodology, while that of Task 5 is to perform the EIA study and report its findings.
3. ASSESSMENT METHODOLOGIES
Several methodologies are available to identify, appraise, and summarize the environmental impacts of a project, among which are:
The ad-hoc methodology, generally used when the timeframe is short, which is carried out by a group of experts that evaluate
the project and identify the impacts.
The check-list methodology, which consists of the preparation of a list of all the environmental impacts generated by the project.
Numeric values varying from 1 to 3 are used to indicate the intensity of the impacts, with 3 being the most intensive impact.
The interaction matrix is a more comprehensive methodology, with the list of impacts included on the X axis, and the list of
activities included on the Y axis. For each impact-activity cell, the impact is estimated using a preselected range of values.
The magnitude of the impact and its importance are evaluated separately.
The choice of an appropriate EIA methodology for the La Leche river flood control project must take into consideration
the project's complexity and importance.
The central feature of the La Leche river flood control project is a high earth dam at La Calzada (Fig. 1)
(Ponce, 2008).
In this context, there are two existing EIA methodologies which are comprehensive enough to warrant consideration in this study.
They are:
The Leopold method is a type of interaction matrix, while the Battelle EES is a check-list methodology with an enhanced capability for
quantitative evaluation. Neither is without its pitfalls,
and both have theoretical and practical strengths and weaknesses.
Yet their inherent quality lies in their usefulness as conceptual frameworks on which to base an appropriate methodology.
The latter would have to be:
3.1 The Leopold Matrix
The Leopold matrix is an early attempt at developing a systematic
procedure to evaluate the impact of a proposed development project on the environment (Leopold et al., 1971).
The methodology has been documented in Appendix I of this report.
The methodology estimates the impact of a list of anthropogenic actions on a list of environmental factors,
using dual scores, one for magnitude and another for importance. The scores vary between 1 (small) to 10 (large).
A matrix of 100 actions and 88 factors is considered, for a maximum possible of 8800 interactions.
A smaller subset of actions and factors is likely to be required in any one application.
The procedure calls for high scores to be explained in the text of the EIA report. To the extent possible,
the magnitude score is based on factual information; however,
the importance score allows a certain amount of subjectivity.
This explicit separation of fact from opinion is an asset of the Leopold matrix.
Advantages of the Leopold matrix are:
Disadvantages are: The list of actions and factors may not be all-encompassing or focused enough,
may be repetitive in some cases, and not applicable in others (Westman, 1984); The method's inability to explicitly consider varying time scales, i.e.,
the short-term and long-term effects; and The subjectivity in the estimation of the
importance score, which may inhibit replication.
The Leopold matrix methodology is properly a tool; with appropriate modifications it may be used to perform
an EIA.
3.2 The Battelle Environmental Evaluation System
The Battelle Environmental Evaluation System (EES) is another early attempt to develop a quantitative
methodology for environmental impact assessment.
The methodology has been documented in Appendix II of this report.
The approach classifies the environment and related social concerns into four (4) categories,
each consisting of several components, for a total of eighteen (18) components.
In turn, each component comprises several parameters, for a total of seventy-eight (78) parameters. A total of 1000 "parameter importance units" (PIU's)
is distributed among the 78 parameters on the basis of socio-psychological scaling techniques and the Delphi procedure
(Dee et al., 1972; Dee et al., 1973). Effectively,
these PIU's constitute parameter "weights."
Each parameter requires a specific quantitative measurement.
The different measurements are converted to common units by means of a scalar or "value function."
A scalar has the specific measurement in the x-axis and a common environmental quality "value" in the y-axis. The latter
varies in the range 0-1. A value of 0
indicates very poor quality, while a value of 1 indicates very good quality.
The EES assesses environmental impact as the difference between the sum of the products of each parameter weight times its respective
environmental quality value, for conditions 'with' and 'without' the proposed project. When the numeric value of environmental impact is negative,
the project has negative environmental impact. Conversely, when the numeric value is positive,
the project has positive environmental impact, i.e., the project is expected to provide a net benefit to the environment.
In the typical case, development projects have a negative environmental impact.
The EES has been criticized for its excessive reliance on scalars in order to provide a quantitative semblance to the analysis
(Westman, 1985).
In an actual application, the standard EES scalars would be subject to scrutiny.
In the worst scenario, most or all of the scalars would have to be developed afresh for a given project.
This complicates the situation inmensely, since it is a great task to develop locally applicable scalars for all 78 parameters.
An advantage of the EES is that the evaluation is independent of the parameters for which there is no perceived change in environmental quality.
Therefore, only the affected parameters would need to be examined in detail. A disadvantage is that the EES explicitly discourages
changing of the PIU's or weights, on the grounds that otherwise, the EIA would be difficult to replicate. Yet, the EES weights represent the opinion
of a specific panel of judges, who cannot represent all of the multiple publics (Westman, 1984). Thus, the EES is doubly flawed, firstly because of
its overreliance of metrics of difficult-to-ascertain quality, and secondly, due to its failure to aggregate the opinions of different publics.
Despite its shortcomings, the EES remains an established quantitative tool for EIA.
With appropriate modifications to tailor it to local conditions, it may assist in a reasoned EIA for the
La Leche project.
4. DEVELOPMENT OF EIA MATRIX
The Leopold matrix, with appropriate modifications,
is chosen as the basic tool to develop an EIA for the La Leche flood control project (Appendix I).
The first step is to develop a subset of actions and factors that are applicable to the project under consideration.
The project is a high earth dam to be used for flood control and water conservation purposes.
Table 1 shows the list of applicable actions, labeled with two digits, for ease of reference.
Table 2 shows the list of applicable factors, labeled with three digits.
Table 3 shows the structure of the modified Leopold matrix, with actions along the horizontal axis and factors along the vertical axis.
The entries shown in Tables 1 and 2 are preliminary, pending additional study and data collection to be performed as part of Task 5:
"Environmental Impact Assessment Report." Extreme care will be taken in Task 5 to ensure that all relevant
actions and factors are considered in the
analysis.
5. THE EES METHODOLOGY
The Battelle EES methodology is chosen here as a framework on which to base a quantitative EIA for the La Leche project
(Appendix II).
The methodology has the following positive features:
A significant advantage
is the method's reliance on weighted differentials;
therefore, no action is required in the case of parameters for which there is no perceived impact.
This feature significantly reduces the extent and complexity of the evaluation.
The EES parameters and their parameter importance units (PIU's) are listed in Table 4.
For application to the La Leche project, only a fraction of parameters listed in Column 3 will require a detailed evaluation.
On a preliminary basis, pending additional information,
the parameters for which evaluation is envisioned are highlighted in red and italics. A final list of relevant parameters will be developed as part of Task 5.
Each evaluated parameter and its PIUI (herein referred to as wi for simplicity) requires a specific quantitative measurement. The methodology converts different measurements into common units by means of a scalar or "value function." A scalar has the specific measurement in the x-axis and a common environmental quality scale or "value" in the y-axis. The latter varies in the range 0 ≤ Vi ≤ 1. A value of Vi = 0 indicates very poor quality, while Vi = 1 indicates very good quality.
Values of Vi = Vi, 0 are obtained for conditions 'without' the project, and Vi = Vi, 1 for conditions 'with' the project. The condition 'without' the project represents the current condition, while that 'with' the project represents the predicted future condition. Only those parameters for which Vi, 1 ≠ Vi, 0 are evaluated. The environmental impact EI is evaluated as follows: EI = ∑ [ Vi, 1 wi ] - ∑ [ Vi, 0 wi ] for i = 1 to n, where n = number of parameters evaluated. For EI > 0, the situation 'with' the project is better than 'without' the project, indicating that the project has positive environmental benefits. Conversely, for EI < 0, the situation 'with' the project is worse than 'without' the project, indicating that the project has aggregated negative impacts. A large negative value of EI indicates the existence of substantial negative impacts.
6. GRL INPUT AND STAKEHOLDER PARTICIPATION
The Terms of Reference for Task 4 state that DLCE, in consultation with GRL, shall select the most appropriate EIA
methodology to employ. It also states that GRL may invite stakeholders to participate in the development of the EIA methodology.
The Consultant recommends that GRL provide appropriate input to the contents of the present report.
GRL may also consider to invite stakeholder participation by convening a meeting for that purpose.
The Consultant obliges himself to modify the contents of the present report as required, after timely input is received from GRL.
As part of Task 5, the Consultant will follow the environmental legislation applicable in Peru, including the
"Ley del Sistema Nacional de Evaluacion del Impacto Ambiental, Ley No. 27446" and related laws.
7. OUTLOOK
The Leopold matrix and the Battelle Environmental Evaluation System (EES) are reviewed to determine their suitability
for use in an environmental impact assessment (EIA) for the La Leche River Flood Control Project. Both methodologies are well established and have been endorsed
by cognizant federal agencies.
The Leopold matrix is relatively simple but primarily qualitative.
The EES is more complex, but the evaluation has a distinct quantitative flavor.
Both methodologies will be applied for the EIA for the La Leche project.
Additional data collection and field surveys will be required to measure the parameters and estimate the value functions.
These activities will be performed as part of Task 5.
APPENDIX I. The Leopold Matrix for Evaluating Environmental Impact.
II.
The Battelle Environmental Evaluation System for Water Resource Planning.
REFERENCES
Dee, N., J. Baker, N. Drobny, K. Duke, and D. Fahringer. 1972.
Environmental evaluation system for water resource planning (to Bureau of Reclamation, U.S. Department of Interior).
Battelle Columbus Laboratory, Columbus, Ohio, January, 188 pages.
Dee, N., J. Baker, N. Drobny, K. Duke, I. Whitman, and D. Fahringer. 1973.
An environmental evaluation system for water resource planning. Water Resources Research, Vol. 9, No. 3, June, 523-535.
Leopold, L. B., F. E. Clarke, B. B. Hanshaw, and J. E. Balsley. 1971. A procedure for evaluating environmental impact. U.S. Geological Survey Circular 645, Washington, D.C.
Ponce, V. M. 2008. La Leche river flood control project, Lambayeque, Peru: Third project report - Final (Hydrology), July 2, 2008.
http://ponce.sdsu.edu/la_leche_third_project_report_080702.html
Westman, W. E. 1985. Ecology, impact assessment, and environmental planning. John Wiley and Sons, New York.
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