La Leche flood control project, Lambayeque, Peru, first project report, Victor Miguel Ponce

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 11, 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
The choice of an appropriate EIA methodology for the La Leche river flood control project must consider 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 matrix, and
the Battelle Environmental Evaluation System.

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:
significantly more focused,
reasonably accurate, and
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:
Its apparent simplicity,
Its comprehensive lists of actions and factors, and
Its perceived popularity in view of its endorsement by a major federal agency (USGS).

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 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 selection of impacts and their magnitude and importance will be performed as part of Task 5: "Environmental Impact Assessment Report."

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 advantages:
It is comprehensive,
It is quantitative,
It has specific application to water resource development projects, and
It is endorsed by the U.S. Bureau of Reclamation.

An additional 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.

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 PIU_I (referred to as w_i 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 ≤ V_i ≤ 1. A value of V_i = 0 indicates very poor quality, while V_i = 1 indicates very good quality.

Values of V_i = V_{i, 0} are obtained for conditions 'without' the project, and V_i = V_{i, 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 V_{i, 1} ≠ V_{i, 0} are evaluated.
The environmental impact E_I is evaluated as follows:
E_I = ∑ [ V_{i, 1} w_i ] - ∑ [ V_{i, 0} w_i ]
for i = 1 to n, where n = number of parameters evaluated.
For E_I > 0, the situation 'with' the project is better than 'without' the project, indicating that the project has positive environmental benefits. Conversely, for E_I < 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 E_I indicates the existence of substantial negative impacts.

6. 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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