- Available methodologies and fields of application
The Environmental Impact Assessment (EIA) is presented and assumed as: i. instrument of public policy, ii. administrative procedure and iii. methodology for the execution of impact studies, which are a central component of the EIA.
methodologies-to-develop-environmental-impact-studiesThese methodologies are aimed at identifying, predicting and evaluating the environmental impacts of the projects, and their results must be complemented, in the presentation of the Environmental Impact Studies (EsIA), with: i. the description of the project under evaluation, ii. the management plan and iii. the monitoring system to be applied.
How to select methodologies? Considerations prior to selecting the methodology should include:
- The current regulatory framework, including the existence of details on the EIS that could be included in the pertinent regulations. The type of project (“structural”, “non-structural”), its magnitude and complexity, and the characteristics of the social environment and physico-biotic potentially affected The objective of the EIS (selection of technological or location alternatives, and identification of impacts) The stage of project development in which the methodology is applied (pre-feasibility, feasibility, design). The relationship between the data requirements for each methodology and their availability The relationship between the economic costs and the required personnel and equipment, with the magnitude and potential expected impacts of the project.Ensuring the independence of the results obtained in relation to the perception of the evaluators.
From the comprehensive consideration of the aforementioned factors arises the diversity of usable and, moreover, available methodologies. In fact, there is no single, universal methodology. This does not preclude ignoring the need for methodologies applicable to the diversity of activities to be evaluated, to the diversity of means and environmental factors potentially affected, and to the complexity of the interactions between factors and the environment.
From the beginning of the EIA procedures to the present, the applicable methodologies are in evolution. At the international level, methodologies of indistinct application have been generated to different activities and technologies of application to specific projects. In the same way, the regulatory frameworks and institutional insertion of the EIAs have been improved, including the improvement of the capacities for official assessment of the EIAs presented.
The regulatory framework on EIA may, in addition to establishing its mandatory nature for those activities and projects likely to affect the environment, advance the guidelines of the content of the EIA. In particular, in different normative frameworks, Terms of Reference have been established which determine the main aspects that must be analyzed and, in general, the way in which the studies containing the EIS must be presented.
The different methodologies must be valued according to the uncertainties and costs associated with each one of them.
It should also be considered that the methodologies are applicable to different stages or levels of the EIS. Considering the stages of an EIS, namely, “qualitative assessment” (general assessment of effects, identification of impactful actions, identification of factors to be impacted, identification of cause-effect relationships) and “quantitative assessment” (prediction of impact magnitude, quantitative impact assessment). The greater uncertainties associated with some of the methodologies may be acceptable in the evaluations corresponding to the initial stages of the projects (“qualitative valuation”), although not in the “quantitative valuation” stage.
In general, we can group the available methodologies into the following categories:
- Impact identification methods
- Interdisciplinary team work (case: Delphi method) Checklists of effects Flow of grammes and causal networks Environmental mapping
- Leopold's matrix Batelle system
Canter (2003) analyzes the applicability of the different EsIA methodologies. They are found in Table Nº 1.
- Methods for identifying impacts
2.1. Effects checklists
They are considered one of the useful methods to start the EsIA process. Its application to the different projects implies that the evaluation team must order the statements considering the subsystems of the environmental system (physical, biotic and abiotic, socio-economic), and within each one of them establish the resources to be impacted and, later, determine the main environmental impacts. The lists allow the evaluation team to advance quickly in: i. the identification of actions that can affect the environment and the population and have effects on the economy, ii. the determination of the components and environmental factors that must be evaluated, and iii. possible environmental impacts.
They are based on the list of environmental factors that must be studied (case of Simple Lists); some systems have more elaborate lists allowing the weighting of the importance between the different factors (case of Descriptive Lists). They are very useful when planning the activities of the EIS.
The Simple Checklists can be oriented to order the environmental factors to be affected or the actions that can affect them. For their part, the Descriptive Control Lists can be based on questionnaires aimed at identifying and defining the impacts for the different components of the environment or affected factors.
Different Control Lists applicable to different activities and projects have been developed (Canter, 2003). Examples include the list developed for gas pipeline projects. Other lists can be developed in the form of questions
(See PDF)
Checklist for small reservoirs.
Instructions: Answer the following questions by marking an X in the appropriate place, consider the activity, construction, exploitation as well as indirect impacts.
NATURAL BIOTIC MEDIA
- Could the proposed activity affect any natural factor or a water resource adjacent or close to the activity areas? IF NOT--
If the answer is YES, specify which natural factor is affected:
| Direct | Indirect | Synergistic | Short term | Long term | reversible | irreversible | severe | moderate | Insignificant | |
| Surface hydrology | () | () | () | () | () | () | () | () | () | () |
| Water quality sup. | () | () | () | () | () | () | () | () | () | () |
| Soil / erosion | () | () | () | () | () | () | () | () | () | () |
| geology | () | () | () | () | () | () | () | () | () | () |
| Weather | () | () | () | () | () | () | () | () | () | () |
- Could the activity affect animal life or fish? IF NOT--
If the answer is YES, specify which animal or fish life is affected.
| Natural habitat | () | () | () | () | () | () | () | () | () | () |
| Fish ecology | () | () | () | () | () | () | () | () | () | () |
- Could the activity affect the natural vegetation? IF NOT--
If the answer is YES, specify what vegetation and to what extent it is affected.
ENVIRONMENTAL RISKS
- Could the proposed activity involve the use, storage, release of, or disposal of some potentially hazardous substance? IF NOT--
If the answer is YES, specify which substance and its possible effect.
- Could the proposed activity cause an actual or probable increase in environmental risks? IF NOT--
If the answer is YES, specify what type
- Could the proposed activity be susceptible to environmental risks due to its situation? IF NOT--
If the answer is YES, specify what type.
CONSERVATION AND USE OF RESOURCES
- Could the proposed activity affect or eliminate land suitable for agricultural or timber production? IF NOT--
If the answer is YES, specify hectares and class of soils that would be affected.
- Could the proposed activity affect commercial fishing or aquaculture resources or their production? IF NOT--
If the answer is YES, specify which type is affected
- Could the proposed activity affect the potential use or extraction of an essential or scarce mineral or energy resource? IF NOT--
QUALITY AND QUANTITY OF WATER
- Could the proposed activity affect the quality of water resources within, adjacent to, or near the activity area? IF NOT--
If the answer is YES, specify which water resources are affected and in what approximate daily quantity.
- Could the proposed activity cause a deterioration in the quality of any area or basin of the water resource? IF NOT--
Source: Canter, L. 1999; cited by Echechuri and Ferraro (FLACSO, 2004).
2.2. Matrices: Leopold's interactive matrix case (1971)
The Leopold matrix is, fundamentally, an impact identification methodology. Basically it is a matrix that presents, in the columns, the actions of the project and, in the rows, the components of the medium and their characteristics. The matrix presents a list of 100 actions and 90 environmental elements; Each action must be considered on each of the components of the environment in order to detect their interaction, that is, the possible impacts.
Among the components of the medium, the matrix establishes the following categories:
- Physical and chemical categories
- EarthWaterAtmosphere
- Biological conditions
- Flora fauna
- Cultural Factors
- Land use Recreation Aesthetics and human interest Cultural status Facilities and activities
- Ecological relationships Other
For its part, the following actions are distinguished:
- Modification of the regime Transformation of land and construction Extraction of resources Production Alteration of land Renewal of resources Changes in traffic Accumulation and treatment of waste Chemical treatments Accidents Others
For each of the categories of environmental elements, the matrix considers the resources, characteristics and environmental effects that the actions can cause. As an example, consider category B.1 (B: Biological components and 1. Flora), and category D. (Ecological relationships).
Biological conditions
- Flora
- TreesShrubsHerbaceousCropsMicrofloraAquatic plantsEndangered speciesBarriersRunners
- Fauna
- BirdsLand animalsFish and crustaceansBenthic organismsInsectsMicro faunaEndangered species
- Ecological relationships Salinization of water resources Eutrophication Insect vectors of diseases Trophic chains Salinization of surface materials Weed invasions Others
(See PDF)
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The example of a matrix for an industrial plant shows that it is possible to select, based on the characteristics and magnitude of the evaluated activity, the criteria to be applied (environmental quality, intensity, extension, temporality, persistence, recovery or reversibility, of the causal relationship, of interaction).
The Leopold matrix, as it has been presented, is a method that can be applied in an expeditious manner, it is low-cost and allows the possible impacts to be identified from a vision of the set of possible interactions. In addition, these matrices are useful for communicating the impacts detected. On the other hand, the methodology does not avoid subjectivity in reference to the quantification of the impacts, it does not allow to visualize the interactions or the impacts of an affected factor on other factors.
In general terms, it is possible to apply the Leopold matrix (Villadrich Morera and Tomasisni (1994) proceeding as follows:
- The actions that make up the project (columns) are identified and those interactions with the components or factors in the environment (rows) on which an impact may occur are sought. The impacts (positive or negative) will be identified with a diagonal. In each box with diagonal (interactions) the magnitude (M) valued from 1 to 10 is indicated, and the extension (E) also valued from 1 to 10. The values will be preceded by the signs "+" or "-" as appropriate. The presentation of the values will be: M / E
As a consequence, the matrix is represented as follows:
(See PDF)
2.2.1. Classification and assessment of impacts
The evaluation of environmental impacts consists of the identification, forecasting, interpretation and measurement of the environmental consequences of the projects. The evaluation of the impacts must be carried out within the framework of adequate procedures that, concurrently, allow identifying the actions and the environment to be impacted, establishing possible alterations and assessing them. This last stage is aimed at expressing the impacts quantitatively and, when this is not possible, qualitatively.
The manifestation of the effect of human activities on the environment to be characterized through the importance of the impact. According to Conesa Fernández Vítora (1997), the importance of the impact is measured “as a function of both the degree of incidence or intensity of the alteration produced, and the characterization of the effect, which in turn responds to a series of attributes of qualitative type such as extension, type of term effect of manifestation, persistence, reversibility, recoverability, synergy, accumulation and periodicity ”.
Attributes of impacts ,.
- Nature of the impact or Nature. The impacts can be beneficial or detrimental. The former are characterized by the positive sign, the latter are expressed as negative. Effect. The impact of an action on the environment can be "direct" -that is, to impact directly-, or "indirect" -that is, it occurs as a consequence of the primary effect, which, therefore, would become a second-order causal.
For the purposes of weighting the value, it is considered:
- Side effect …………………………… 1 Direct effect ………………………………..4
3. Magnitude / Intensity. It represents the incidence of the causal action on the impacted factor in the area where the effect occurs.
To weight the magnitude, we consider:
- Low …………………………………………..1 Medium low …………………………………… 2 Medium high ………………………………… … 3High …………………………………………..4Very high ……………………………………… 8Total ……………………………… ………… 12
4. Extension. Sometimes the incidence of the impact is circumscribed; in other cases it spreads reducing its effects (air and water pollution) until they are not measurable. In some cases, its effects can manifest itself beyond the project area and its location. For example, the secondary effects on the atmosphere (CO2 and its incidence in the greenhouse effect) and the effects of degradation of wetlands or contamination of crops (reduction of reproductive or feeding areas of migratory birds and the direct mortality of birds, and its effects on ecological systems in other countries).
The impact can be localized (punctual) or spread throughout the project or activity environment (it is considered total).
The extension is valued as follows:
- One-off impact ……………………………… 1Partial impact ……………………………… 2Extensive impact ……………………………… 4Total impact ……………… ………………….8
There are other considerations that must be made when assessing the extension. Indeed, it must be considered that the extension refers to the zone of influence of the effects. If the place of impact can be considered a “critical place” (alteration of the landscape in an area valued for its scenic value, or discharge upstream of a water intake), four (4) units are added to the value obtained. If in the case of a “critical” impact, corrective measures cannot be taken, the location of the activity that, within the framework of the project, gives rise to the effect considered, must be changed.
5. Time. It refers to the time elapsed between the action and the appearance of the impact. In order to evaluate the impacts deferred in time, models or previous experience are needed. For example, in the case of eutrophication processes in water bodies, it is possible to have models.
The prediction of the moment of appearance of the impact, the better the shorter the term of appearance of the effect. Furthermore, prediction is important because of the impact correction measures that must be carried out.
The moment is valued as follows:
- Immediate …………………………………….4Short term (less than one year) ……………… 4Medium term (1 to 5 years) …………………..2 Long term (more than 5 years) ………………… 1
If the moment of occurrence of the impact is critical, four (4) units must be added to the corresponding ones.
6. Persistence. It refers to the time that the effect manifests itself until it returns to the initial situation naturally or through corrective measures. An effect considered permanent may be reversible when the causal action ends (in the case of pollutant discharges) or irreversible (in the case of affecting the scenic value in areas of tourist or urban importance through the alteration of geoforms or by cutting down a forest). In other cases the effects may be temporary.
Impacts are valued as follows:
- Fleeting ………………………………………… 1Temporary (between 1 and 10 years) ………………… 2Permanent (duration greater than 10 years ……… 4
7. Reversibility. Persistence and reversibility are independent. This attribute refers to the possibility of recovery of the component of the environment or factor affected by a certain action. Only the recovery made naturally after the action has ended is considered. When an effect is reversible, after the residence time has elapsed, the factor will return to the initial condition.
The following values are assigned to Reversibility:
- Short term (less than one year) ……………… 1 Medium term (1 to 5 years) …………………..2 Irreversible (more than 10 years) ………………… 4
8. Recoverability. It measures the possibility of recovering (totally or partially) the initial environmental quality conditions as a consequence of the application of corrective measures.
Recoverability is assessed as follows:
- If the recovery can be total and immediate ……….1 If the recovery can be total in the medium term….2 If the recovery can be partial (mitigation) …… 4 If it is irrecoverable ………………………………… … 8
9. Synergy. It refers to the fact that the global effect of two or more simple effects is greater than the sum of them, that is, when the effects act independently.
It is given the following values:
- If the action is not synergistic on a factor… 1If it presents a moderate synergism ………..2If it is highly synergistic …………………… 4
If instead of "synergism" there is "weakening", the value considered is presented as negative.
10. Accumulation. It refers to the increase of the effect when the cause persists (effect of toxic substances).
The assignment of values is carried out considering:
- There are no cumulative effects ……………….1 There are cumulative effects …………………..4
11. Periodicity. This attribute refers to the rate of appearance of the impact.
It is assigned the following values:
- If the effects are continuous …………………….4If the effects are periodic …………………… 2If they are discontinuous ……………………………..1
12. Importance of Impact
Conesa Fernández Vítora express the “importance of impact” through:
I = ± (3 Importance + 2 Extension + Moment + Persistence + Reversibility + Synergism + Accumulation + Effect + Periodicity + Recoverability)
The Importance of Impact values vary between 13 and 100. They are classified as:
- Irrelevant (or compatible) when they present values below 25. Moderate when they present values between 25 and 50. Severe when they present values between 50 and 75. Critical when their value is greater than 75.
2.3. Network diagram
Network diagrams are based on analyzing and integrating the causes of the effects on the environment and the factors impacted by them; considered in succession the primary, secondary and tertiary effects. Although the information they present is minimal (Canter, 2000), they are useful when organizing and starting work in interdisciplinary teams and, in addition, identifying the impacts of projects and the causal relationships between actions and impacts.
The diagrams can be made in a generic way for each type of activity (construction of dams, change of land use, communication routes, others). In this case, they guide the work team on the cause-effect relationships on which they should pay attention or consider as a priority. The evaluation team will be able to modify the diagram, adapting it to the particular conditions (natural, social, economic) of the project location and their interactions. This activity implies broadening and clarifying the knowledge of cause-effect relationships, and allows the evaluation team to be consolidated and to recognize, analyze and integrate the conceptual and disciplinary views of its members. The diagrams, too, can be elaborated from the beginning by the evaluation team.
As an example, a diagram is presented in which the following aspects are systematically and successively analyzed: i. the project alternative, ii. the resources affected and the change in land use, iii. the effects on the natural environment (physical and chemical, and biological and ecological) and socio-economic, and iv. the weighting of the probable importance of the ultimate effects. The diagram presented is oriented to the construction of dams. It should be considered that in particular cases, other considerations should also be made. For example, in the event that the river is culturally important or that the construction of the dam affects the way of life of the local society.
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- Battelle system
It is an evaluation methodology based on the consideration of impact indicators. The system is based on the identification of representative parameters of the environmental situation and that allow assessing the changes that occur as a consequence of the evolution of the environmental system itself or of the effects, on the environment, of human activities. The methodology uses an index that, expressed in units of environmental impact, should allow characterizing the overall impact of the project. The index used comes from the assessment of the indicators measured using, for all of them, a measurable numerical scale, that is, it makes it possible to add them in order to obtain an integrating value of the environmental effects of the project.
The original system identifies four (4) environmental categories, 18 components, and 78 parameters. The levels of information required for the development of the system increase from category to component and from this to parameter.
The categories considered are the following:
ECOLOGY
CONTAMINATION
AESTHETIC ASPECTS
ASPECTS OF HUMAN INTEREST
For their part, the 18 environmental components are the following:
Species and populations
Habitat and communities
Ecosystems
Water contamination
Atmospheric pollution
Soil contamination
Noise
Floor
Air
Water
Biota
Craft objects
Composition
Educational and scientific values
Historical values
Culture
Sensations
Lifestyles
Parameters must be appropriate. And they will be to the extent that they are representative of the environmental quality of the environment in which the measurements are made, that they are identifiable and measurable, and that they respond to the prediction, interpretation and evaluation needs of the project. Those responsible for the EIS must select said parameters based on their knowledge of the environment, the characteristics and impacts of the project, the knowledge available on the subject and their own experience.
To be used in the system, the results obtained from each parameter -measured in units proper to each one of them and, therefore, heterogeneous as a function of the set- must be transformed into commensurable units -abstract-, for example in “Units of Environmental impact". For this, the data is transformed into its equivalence of environmental impact index. Subsequently, the indices are weighted due to their importance in the environmental framework of the environment.
Transformation of the parameters into indices of environmental quality. The measured value of a parameter varies and it is possible to determine its “optimal” and “worst” value -or level-. Between both levels, intermediate values are produced that are representative of the quality of the environment considered. The relationship between the measured values and the environmental quality index is made through a transformation function, which derives from the knowledge of each factor and its effects. In general, the transformation function can be presented as:
CA j = f (M j)
Where CA is the environmental quality index of a parameter and Mj is the magnitude of the impact caused.
The CA index is expressed, by convention, between 0 and 1, with 0 being the situation with the worst environmental quality of the parameter considered and 1 being the level that can be considered optimal.
According to Conesa Fernández Vítora, nine (9) basic forms of the transformation functions should be considered, each of which can, in addition, the direct form -increases environmental quality when the measurable value of the factor increases. In the attached Fig. Some of the basic transformation functions are presented -in their direct form.
Examples of transformation functions are shown in the following Fig. (Source: Canter, 2000, citing work done in 1970 by the US National Health Foundation). The indices presented were prepared by a panel of experts for inclusion in a general water quality index, and are referred to values between 0 and 100. They can be considered as indicative of the matter developed here. The gray area between the dotted lines includes all the responses obtained from the panel; the solid line represents the "mean curve" obtained from averaging the responses obtained.
The development of the indices requires, as seen in the previous case, the participation of a panel of experts, who, in addition, must be familiar with the project's environment (biotic and abiotic), social and economic. As Conesa Fernández Victora (1997) points out, the transformation function may be different for different environments.
Weighting of parameters. The parameters used contribute differently to representing the environmental quality of a site. Therefore, it is important to give each parameter a weight or weight index (UIP), which is expressed in “units of importance”. In the Batetelle system the IPUs are indicated for each parameter.
The expression of the unit of environmental impact (UIA) of each parameter is:
UIA = CA × UIP
Finally, the final evaluation is carried out considering each parameter in the situation of without project and with project, namely:
UIA per project = UIA with project - UIA without project
As UIAs are commensurable, the final environmental impact assessment may be obtained by adding the UIAs for each parameter.
The system also uses red flags to highlight critical situations, even when the global impact is admissible.
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Case study of Terms of Reference: Decree 2131 of the Province of Córdoba and the Terms of Reference applied within the framework of the aforementioned Decree, for the EIAs of native forests.
See PPoint “Introduction to EIA”.
Leopold, LB et alt "A procedure for Evaluating Environmental Impact", circular 645, US Geological Survey, Washington, DC, 1971
Source: Conesa Ferández Vítora (1997); Viladrich and Tomasini, 1999.
Viladrich and Tomasini (1999? Consider the inclusion of a certainty parameter.
The values set forth in the first of the sources listed above are considered.
Some authors (Viladrich and Tomasini, 1999) propose the possibility of jointly considering Persistence and Reversibility.
Measures of environmental factors or biological species are considered "indicators". An indicator factor is selected by the importance of the effect it measures, either because it directly affects environmental quality and the effects on people's health, and social and economic, or because it contributes to the appearance of other negative effects. For its part, a biological indicator (plant or animal) is selected on the basis of sensitivity or tolerance to environmental situations of stress or contamination. The "indicators" are of fundamental importance in environmental management; They are used for the evaluation of the environmental situation of a site, the establishment of environmental baselines, the monitoring of environmental evolution and that of the effects of human activities.
Among the environmental indicators aimed at assessing the physical and biological environment, we can mention: emissions of different gases or grouping causal gases of different effects such as GHGs, volume of waste produced (municipal, industrial, hazardous), species in different categories threat, others. Among the indicators of the social and economic environment, the following should be mentioned: energy use, industrial production, population growth, occurrence of diseases related to environmental factors, others.
The "indices" are established based on different "indicators", that is, combining, in a more or less complex way, different factors that contribute to environmental quality. They are important when defining, in a comprehensive way, the environmental situation or evolution. On the other hand, if it is not used by using the indicators that make them up individually, they can serve to mask situations, especially in those cases where one of the factors whose indicator is used can produce synergistic effects on other indicators. The monitoring of a certain index can mask the change in the trend of an indicator, which in itself can be important when forecasting the possible or probable future of the system under consideration.
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