Chapter 6: Executing the EIA Process

Transcription

1 ENVS402 Environmental Impact Assessment Chapter 6: Executing the EIA Process 6.3 Methods of Identifying Impacts 1

2 Methods of identifying impacts (Ref. Lary W Canter, 1996, Environmental Impact Assessment. Mc Graw Hill international Editions, Civil Engineering Series, page ) Matrices Networks Checklists Overlay Mapping Simple Network Simple Map Stepped Others Descriptive Scaling Questionnaire 2

3 Methods of identifying impacts 1.1 Simple Matrices The interaction matrix ti ti method developed dby Leopold et al. (1971) will be used as an example. The matrix lists approx. 100 specified actions and 90 environmental items. Actions causing impacts Environmental Items M I 3 Figure: Leopold Matrix, M= Magnitude; I= Importance

4 Methods of identifying impacts 1.1 Simple Matrices Example of Actions and Environmental items in Leopold Interaction Matrix. Environmental Factors (Category): A. Physical and chemical characteristics (Earth, Water, Atmosphere, Processes) B. Biological i l conditions C. (Flora, Faun) Cultural factors (Land M use, Recreation, I Aesthetics and human interests, Cultural interests, Manufactured facilities and activities) D. Ecological relationships E. Others Leopold Matrix, M= Magnitude; I= Importance Actions causing impacts (category): 1. Modification of regime 2. Land transformation and construction 3. Resource extraction 4. Processing 5. Land alteration 6. Resource renewal 7. Changes in traffic 8. Waste emplacement and treatment 9. Chemical treatment 10. Accidents 11. Others 4

5 Methods of identifying impacts 1.2 Concept of Stepped Matrices: 1. A stepped matrix is also called cross impact matrix can be used to address secondary and tertiary impacts of initiating actions. 2. A stepped matrix is one in which environmental factors are displaced against other environmental factors. 3. The consequences of initial changes in some factors on other factors can be displayed. 5

6 Methods of identifying impacts Concept of Stepped Matrix ACTIONS A B F G H A B FACTORS C D E F A B H I 6 J

7 Leopold matrix showing Magnitude and Intensity on scale of 1 to 10 Simple matrix Atiiti Activities Land transformation & Compaction Adverse effect No Effect Beneficial Effect Land Use Water Resources Air quality Noise & Vibration Transportation systems

8 Oh Other Type of Matrices 1. Modified Graded matrix (Lohani and Than) 2. Environmental Compatibility matrix 3. Impact Summary matrix

9 Environmental Compatibility Matrix for Upper Bhotekoshi Hydropower project Decision Matrix for Upper Bhotekosi

10 Environmental Impact Matrix of Arun III Hydro Project A Part of Impact Summary Matrix

11 Environmental Impact Matrix of Arun III Hydro Project A Part of Impact Summary Matrix

12 Methods of identifying impacts 2. NETWORKS Networks are those methodologies which integrate impact causes and consequences through identifying interrelationships between casual actions and the impacted environmental factors, including those representing secondary and tertiary effects. - Larry W. Canter, 1996, page 81 12

13 Methods of identifying impacts 2. NETWORKS 13

14 Use of Networks method in road sector example Rural road project Land and soil Forests Air and water Conversion of Loss of forest Emission of air arable land due to area/species pollutants discharge road construction habitat Decline in crops production Soil erosion and downstream sedimentation Flooding and siltation, change in river hydrology changes Loss of endemic or protected or endangered species Change in microclimate, decline in aquatic or terrestrial productivity Migration Change in productivity of terrestrial, aquatic and manmade system Change in employment opportunities and quality of life 14

15 Methods of identifying impacts 1. Simple lists 2. Descriptive checklists 3. Scaling checklists 4. Questionnaire checklist 15

16 Methods of identifying impacts Simple Checklist S.N Environmental Component Sub component 1. Land Physical landscape Land use Water resources Air and noise 2. and agriculture Biological Wildlife Aquatic life Birds Biodiversity Habitat 3. Goods and services Human, social, Irrigation and agriculture production Drinking water, health and sanitation Human capital Social capital Accidents and occupational safety Private properties/infrastructure and public economic, and cultural and religious (including gender, ethnicity, ) utility structures Livelihoods Employment Income Archaeological Chautara, pati/pauwaa, monument graveyard; temple, shrine

17 Methods of identifying impacts 2. Descriptive Checklist 17

18 Methods of identifying impacts Factors Habitat quality Species Size/abundance Duration Reversibility Magnitude 3. Scaling Checklist Impact Beneficial impact Adverse impact = low; 2=medium; and 3=high 18

19 4. Questionnaire Checklist 1. Might the project affects any protected area? NO YES If YES specify which area, in what ways (direct, indirect), nature of the impact (short or longterm, reversible or irreversible, cumulative, synergistic), and severity Will the project site locate near the valuable forests? No YES If YES, identify the forests, their value and describe possible direct and indirect consequences of project 1. Will the project locate existing landslides or landslides and erosion prone areas, and hence increase the slope instability, landslides and erosion? NO YES If YES specify the sites, and explain how Might the project disrupt natural drainage pattern?.no YES If YES specify the location and potential consequences.

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21 Overlay Mapping Overlay mapping is a simple technique for displaying the impact areas The resources likely are to be impacted and intensity of impacts can be presented through color shading 21

22 Conclusion In the history of EIA, an enormous variety of methods have been devised to help undertake EIAs and prepare EIA reports. These EIA methods are structured which allow impact to be identified, manipulated and presented. Some methods are suited to one of these tasks, whereas other methods for all of them. These EIA methods are tools used to assist EIA implementation. They should be modified, adapted, extended or simplified to meet the needs of a particular EIA. 22