Fig. 1   Proposed damsite on La Leche river at La Calzada.

LA LECHE RIVER FLOOD CONTROL PROJECT

LAMBAYEQUE, PERU

ENVIRONMENTAL IMPACT ASSESSMENT

PRELIMINARY REPORT

November 24, 2008

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:

  1. 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.

  2. 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.

  3. 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:

  1. the Leopold matrix, and

  2. the Battelle Environmental Evaluation System.

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:

  1. significantly more focused,

  2. reasonably accurate, and

  3. based on sound ecological principles.

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:

  1. Its apparent simplicity,

  2. Its comprehensive lists of actions and factors, and

  3. Its perceived popularity in view of its endorsement by a major federal agency (USGS).

Disadvantages are:

  1. 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);

  2. The method's inability to explicitly consider varying time scales, i.e., the short-term and long-term effects, and

  3. 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 will 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.

Table 1.   Actions in the modified Leopold matrix.

ACTIONS

•

Proposed
actions
which
may
cause
environmental
impact

•

 10.  Project features 11.  Dams
12.  Spillways
13.  Canals
14.  Desilting basins
15.  Access roads
20.  Construction operations 21.  Blasting and drilling
22.  Cut and fill
23.  Surface excavation
24.  Subsurface excavation
30.  Extraction 31.  Soil materials
32.  Cement
33.  Aggregates
40.  Processing 41.  Soils
42.  Concrete
43.  Steel
50.  Hazards 51.  Dam failure
52.  Slope instability
53.  Explosions


Table 2.   Factors in the modified Leopold matrix.

FACTORS

•

Existing
characteristics
and
conditions
of
the
environment

•

100.
Physical
and
chemical 		110.
Lithosphere 		111.  Soils
112.  Soil moisture
113.  Albedo
114.  Nutrients
115.  Land forms
120.
Hydrosphere 		121.  Surface water
122.  Groundwater
123.  Surface water quality
124.  Groundwater quality
125.  Temperature
126.  Salinity
127.  pH
128.  Redox potential
130.
Atmosphere 		131.  Precipitation
132.  Relative humidity
133.  Temperature
134.  Air quality
200.
Biological 		210.
Terrestrial
Flora 		211.  Trees
212.  Shrubs
213.  Grasses
214.  Crops
215.  Microflora
216.  Endangered species
220.
Aquatic
Flora 		221.  Wetland species
222.  Endangered species
230.
Terrestrial
Fauna 		231.  Birds
232.  Mammals
233.  Insects
234.  Microfauna
235.  Endangered species
236.  Barriers
237.  Corridors
240.
Aquatic
Fauna 		241.  Fish and shellfish
242.  Benthic organisms
243.  Microfauna
244.  Endangered species
245.  Barriers
246.  Corridors
300.
Cultural 		310.
Land use 		311.  Forests
312.  Grasslands
313.  Agriculture
314.  Rural
315.  Urban
316.  Wilderness
317.  Wetlands
320.
Recreation 		321.  Hunting
322.  Fishing
323.  Boating
324.  Swimming
325.  Camping and hiking
326.  Leisure
330.
Aesthetics 		331.  Scenic views
332.  Wilderness qualities
333.  Open space qualities
334.  Unique physical features
335.  Unique species
336.  Unique ecosystems
337.  Natural reserves
340.
Historical 		341.  Archaeological sites
342.  Historical sites
343.  Monuments
350.
Sociological 		351.  Lifestyles
352.  Public health
353.  Employment
354.  Population density
360.
Anthropogenic 		361.  Structures
362.  Transportation
363.  Utilities
364.  Water supply
365.  Waste management

Table 3.   Structure of the modified Leopold matrix.
Actions ⇒ 11 12 13 14 15 21 22 23 24 31 32 33 41 42 43 51 52 53
Factors ⇓
100 111 0/0                                  
112                                    
113                                    
114                                    
115                                    
121                                    
122                                    
123                                    
124                                    
125                                    
126                                    
127                                    
128                                    
131                                    
132                                    
133                                    
134                                    
200 211                                    
212                                    
213                                    
214                                    
215                                    
216                                    
221                                    
222                                    
231                                    
232                                    
233                                    
234                                    
235                                    
236                                    
237                                    
241                                    
242                                    
243                                    
244                                    
245                                    
246                                    
300 311                                    
312                                    
313                                    
314                                    
315                                    
316                                    
317                                    
321                                    
322                                    
323                                    
324                                    
325                                    
326                                    
331                                    
332                                    
333                                    
334                                    
335                                    
336                                    
337                                    
341                                    
342                                    
343                                    
351                                    
352                                    
353                                    
354                                    
361                                    
362                                    
363                                    
364                                    
365                                   0/0

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:

  1. It is comprehensive,

  2. It is quantitative,

  3. It has specific application to water resource development projects, and

  4. It is endorsed by the U.S. Bureau of Reclamation.

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. A final list of parameters will be developed as part of Task 5.

Table 4.   Categories, components, and parameters of the Battelle EES.
(1) (2) (3) (4)
Categories Components Parameters PIU

Ecology

Species
and
populations

1.  Terrestrial browsers and grazers 14
2.  Terrestrial crops 14
3.  Terrestrial natural vegetation 14
4.  Terrestrial pest species 14
5.  Terrestrial upland game birds 14
6.  Aquatic commercial fisheries 14
7.  Aquatic natural vegetation 14
8.  Aquatic pest species 14
9.  Sport fish 14
10.  Waterfowl 14

Habitats
and
communities

11.  Terrestrial food web index 12
12.  Land use 12
13.  Terrestrial rare and endangered species 12
14.  Terrestrial species diversity 14
15.  Aquatic food web index 12
16.  Aquatic rare and endangered species 12
17.  River characteristics 12
18.  Aquatic species diversity 14

Pollution

Water

19.  Basin hydrologic loss 20
20.  BOD 25
21.  Dissolved Oxygen 31
22.  Fecal coliforms 18
23.  Inorganic carbon 22
24.  Inorganic nitrogen 25
25.  Inorganic phosphate 28
26.  Pesticides 16
27.  pH 18
28.  Stream flow variation 28
29.  Temperature 28
30.  TDS 25
31.  Toxic substances 14
32.  Turbidity 20

Air

33.  Carbon monoxide 5
34.  Hydrocarbons 5
35.  Nitrogen oxides 10
36.  Particulate matter 12
37.  Photochemical oxidants 5
38.  Sulfur dioxide 10
39.  Other 5

Land

40.  Land use 14
41.  Soil erosion 14
Noise 42.  Noise 4

Aesthetics

Land

43.  Geologic surface material 6
44.  Relief and topographic character 16
45.  Width and alignment 10

Air

46.  Odor and visual 3
47.  Sounds 2

Water

48.  Appearance 10
49.  Land and water interface 16
50.  Odor and floating materials 6
51.  Water surface area 10
52.  Wooded and geologic shoreline 10

Biota

53.  Animals - domestic 5
54.  Animals - wild 5
55.  Diversity of vegetation types 9
56.  Variety within vegetation types 5
Manmade objects 57.  Manmade objects 10

Composition

58.  Composite effect 15
59.  Unique composition 15

Human
interest

Educational/ scientific packages

60.  Archaeological 13
61.  Ecological 13
62.  Geological 11
63.  Hydrological 11

Historical packages

64.  Architecture and styles 11
65.  Events 11
66.  Persons 11
67.  Religions and cultures 11
68.  Western frontier 11

Cultures

69.  Indians 14
70.  Other ethnic groups 7
71.  Religious groups 7

Mood/ atmosphere

72.  Awe-inspiration 11
73.  Isolation/solitude 11
74.  Mystery 4
75.  Oneness with nature 11

Life
patterns

76.  Employment opportunities 13
77.  Housing 13
78.  Social interactions 11

Each evaluated parameter and its PIUI (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.

Fig. 2   Proposed La Calzada reservoir site at the confluence of La Leche River with Cincate Creek.

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