ASSESMENT OF CUMULATIVE IMPACTS

PRESENTED BY: SUPERVISED BY:

Minhaj Aijaz Memon Dr. Dmitry Palekhov

Uchechukwu Ibegbulam

Tra My Phung

Lina Marcela Palomo Garcés

1
 TYPES OF CUMULATIVE IMPACTS AND THEIR CONCEPTS

Presented by: Minhaj Aijaz Memon

2
 CONTENT

I. Introduction:
1. Cumulative Impacts
2. Direct and Indirect Impacts

II. Types of Cumulative Impacts:

1. Concept of Additive Impacts
2. Concept of Synergistic Impacts

3
 I. INTRODUCTION
 The US Council on Environmental Quality (CEQ) has indicated that there is increasing
evidence that the most destructive environmental effects may actually result not from the
direct and indirect effects of a given action, but instead from the combination of individual
minor effects of numerous actions over time.

Image Source: https://www.cleanwateraction.org/features/cumulative-impacts-pollution

4
Source: CEQ NEPA, 1997
 CUMULATIVE IMPACTS
Definition of Cumulative Impact According to the U.S Council on Environmental
Quality:

“…the impact on the environment that

results from the incremental impact of the
action when added to other past, present,
and reasonably foreseeable future actions,
regardless of which agency (federal or non-
federal) or person undertakes such other
actions. Cumulative impacts can result
from individually minor but collectively
significant actions taking place over a
period of time.”

5
Source: CEQ NEPA, 1997
 CUMULATIVE IMPACTS
Proposed
Project

Direct &
Indirect Impact

Direct & Direct &

Past Actions Indirect
Cumulati Future
Indirect
Impact ve Impact Impact Actions

Direct &
Indirect Impact

Other Present
Actions
6
Source: CEQ NEPA, 1997
 DIRECT AND INDIRECT IMPACTS

Definition of Direct and Indirect Impacts According to the U.S Council on

Environmental Quality:

Direct Impacts Indirect

“…are caused Impacts
by the action and are
later in time or farther removed in
distance, but are still reasonably
foreseeable. Indirect effects may
include growth inducing effects and
“…are caused by the action and
other effects related to induced
occur at the same time and place.”
changes in the pattern of land use,
population density or growth rate,
and related effects on air and water
and other natural systems, including
ecosystems.”

7
Source: CEQ NEPA, 1997
 DIRECT AND INDIRECT IMPACTS

Direct Passage of Indirect

Project Time/Remot
Environment Environment
Action e in
al Impacts al Impacts
Distance

8
Source: CEQ NEPA, 1997
Direct Impact: Habitat Loss Due to Roadbed Indirect Impact: Habitat Losses Due to Construction of
Grading Interchange

Cumulative Impact: Habitat Losses Due to Various 9

Construction Activities
 II. TYPES OF CUMULATIVE IMPACTS

Cumulative
Impacts

Synergisti
Additive c
Impacts (Interactiv
e)

10
Source: Eccleston, 2011
 CONCEPT OF ADDITIVE IMPACTS
Additive impacts occur when the magnitude of combined effects is equal to the sum of
individual effects. Common examples encountered in CIA for NEPA EIAs & EISs include:

Image Source: https://www.nps.gov/subjects/air/sources.htm Image Source:

http://www.uky.edu/WaterResources/public/watersheds.
php
11
Source: Eccleston, 2011
 CONCEPT OF SYNERGISTIC IMPACTS

 When effects are combined, the result

may be substantially greater or less than
that expected based on additivity.
 A greater than expected result can be
described as synergistic.
 Less than expected result can be
described as antagonistic.
 Synergism is only considered in CIA.
 Often cannot be expressed quantitatively
and are much more complex and difficult
to assess than additive effects.

12
Source: Eccleston, 2011
 CONCEPT OF SYNERGISTIC IMPACTS
Example of Synergistic Impacts:
 Consider that the combined effects of
terrestrial habitat losses can be expected
to be additive when the habitat type is
abundant in the region, but can be
synergistic when the habitat type is
regionally scarce.
 For example, bird species favoring large
expanses of forest cover become
increasingly scarce once landscapes lack
forest tracts below area thresholds that
differ by species.

13
Source: Eccleston, 2011 Image Source: Cornell University
 EIA FOR ASSESING CUMULATIVE IMPACTS

Presented by: Uchechukwu Ibegbulam

14
 CONTENT

I. What should be considered when assessing cumulative impacts using EIA

II. EIA for assessing cumulative impacts
III. Approaches for assessing cumulative impacts
IV. Difficulties for discussing cumulative impacts on project level

15
 I. WHAT SHOULD BE CONSIDERED WHEN ASSSESSING
CUMULATIVE IMPACTS USING EIA ?

 Focus should be on valued ecological components, including arctic sensitive areas

 Spatial boundaries should be defined with respect to valued ecological
components
 Temporal boundaries will vary with projected life span of project impacts
 Assessment should be kept at reasonable and manageable levels

16
 II. EIA FOR ASSESSING CUMULATIVE IMPACTS
Scoping
 Identify regional issues of concern
 Select appropriate regional VECs (valued ecosystem components)
 Identify spatial and temporary boundaries
 Identify other actions that may affect the same VECs
 Identify potential impacts due to actions and possible effects

Analysis of Effects
 Complete the collection of regional baseline data
 Assess effects of proposed action on selected VECs
 Assess effects of all selected actions on selected VECs

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 EIA FOR ASSESSING CUMULATIVE IMPACTS CONTD

Identification of Mitigation
 Recommend mitigation measures

Evaluation of Significance
 Evaluate the significance of residual effects
 Compare results against thresholds or land use objectives

Follow-Up
 Recommended regional monitoring and effect management

18
III. APPROACHES FOR ASSESSING CUMULATIVE IMPACTS

Reg
Proj
ion
ect-
al-
Bas
Bas
ed
ed
App
App
roac
roa
h
ch

19
 The Project-based approach
incorporates the assessment of
cumulative effects into the EIA
process.

 Regional-Based approach assesses

cumulative effects as part of the
SEA process, and then uses the
outcomes of this process to inform
future EIA process.

20
IV. DIFFICULTIES FOR DISCUSSING CUMULATIVE IMPACTS ON
PROJECT LEVEL
Determining significance
By considering the effects of a proposed project along with the results of past, curre
nt and reasonably foreseeable future projects . Decisions are based on whether cu
mulative effects are deemed to be “significant." There are two criteria for measurin
g significance — indicators and reference points.
Incorporating uncertainty
Because our knowledge of the connections between human activities, stressors and
ecological components is incomplete, uncertainty is an inherent component of
any

21
 DIFFICULTIES FOR DISCUSSING CUMULATIVE IMPACTS ON
PROJECT LEVEL (CONT.)
Cumulative effects analysis. There is uncertainty in quantifying the amount of an
individual stressor produced by an activity (e.g., how much sediment is
resuspended during a dredging operation) and the extent to which that stressor
impacts the ecosystem (e.g., how many species are affected by sediment
resuspension).
Choosing an appropriate spatial scale
The spatial scale of cumulative effects assessments is typically limited because the
spatial extents of effects particularly indirect effects are not well documented. As a
result, potentially important spatial effects from multiple stressor interactions are
omitted

22
 DIFFICULTIES FOR DISCUSSING CUMULATIVE IMPACTS ON
PROJECT LEVEL (CONT.)
Because individual projects may contribute only a small amount of stress to the
physical environment or specific ecological components in a limited area when
compared to the interacting processes that occur among multiple stressors across
multiple spatial scales
 Selecting the appropriate temporal scale
The effects from a proposed project are generally evaluated based on temporal
scales defined by the construction or initial phase of a project and the operating
lifetime of the project and any decommissioning, in combination with the effects of
other nearby projects.

23
 DISCUSSION ON METHODS OF CUMULATIVE IMPACTS
ASSESSMENT

Presented by: Tra My Phung

24
 CONTENT

I. Classification of cumulative impacts assessment methods

II. Methods for cumulative impacts assessment
1. Expert opinion
2. Consultations and questionnaires
3. Spatial analysis
4. Network and systems analysis
5. Matrices
6. Modeling

25
 I. CLASSIFICATION OF CUMULATIVE IMPACTS
ASSESSMENT METHODS

Spatial
Matrice analysi Checklists
s s

Network
Expert and
opinion systems
analysis

Consultations Carrying
and Modelling capacity
questionnaire analysis
s
26
Source: EC, 1999
 II. METHODS FOR CUMULATIVE IMPACTS ASSESSMENT
Expert Opinion
 Expert panels can be formed to facilitate exchange of information
 Application:
• all project types and all environmental conditions
• throughout a project
• identify and assess cumulative impacts for simple projects

Advantages Disadvantage
s
• can consider such impacts as an • some specialists or experts may
integral part of the assessment be remote from the main project
team

27
Source: modified from EC,
Consultations and Questionnaires
 Gathering information about a wide range of actions, including those in the past,
present and future which may influence the impacts of a project
 Application:
• all project types and environmental conditions
• used to help identify where impacts would occur for a wide range of project
types through data collection

Advantages Disadvantages
• flexible • prone to errors of subjectivity
• can be focused to obtain specific • questionnaire can be time-
information consuming, and risk of poor
• considers potential impacts early on response

28
Source: EC, 1999
Spatial analysis
 Uses Geographical Information Systems (GIS) and overlay maps to identify where
the cumulative impacts of a number of different actions may occur
 Application:
• a range of projects and environmental conditions
• best suited for identifying physical impacts in terms of geographical location

Advantage Disadvantage
• GIS flexibles and easy to update • GIS cansbe expensive and time-
• can consider multiple projects and consuming
past, present and future actions • difficult to quantify impacts
• allows clear visual presentation • problems in updating overlays

29
Source: EC, 1999
 AN EXAMPLE OF SPATIAL ANALYSIS
Indirect and Cumulative Impacts

Sites of
Ecological
Importanc
e
Water
Quality Overlaying
Component
Landscape Maps
Consideration
s
Development
A (e.g.
Industrial
Plant)
Development
B (e.g. road
scheme)

Complete Composite Map

30
Source: modified from EC, 1999
Network and systems analysis
 Based on the concept
• that there are links/interaction pathways between individual elements of the
environment, and
• that when one specifically affected element has effects on those elements
which interact with it
 Application:
• all projects
• used to consider physical as well as socio-economic aspects
Advantages Disadvantage
• mechanism of cause and effect are s or temporal scale
• no spatial
made explicit • diagrams can become too
• use of flow diagrams can assist with complex
understanding of impacts

31
Source: EC, 1999
 AN EXAMPLE OF NETWORK AND SYSTEMS ANALYSIS

Receptors Receptors

Impact Flora Humans

Severance of
habitat
Impact Fauna Fauna

Surface
Impact Impact Flora
Changes to water
drainage Groundwate Surface
Impact Impact
r water

Primary Secondary
impacts impacts
32
Source: EC, 1999
AN
EXAMPLE
OF
NETWORK
AND
SYSTEMS
ANALYSIS

33
Source: EC, 1999
Matrices
 A more complex form of checklist
 Application:
• a range of projects and environmental conditions by selecting an appropriate
matrix
• consider both physical and socio-economic impacts
Advantage Disadvantage
• a good visuals summary of impacts • can be scomplex and cumbersome
• Can be adapted to identify and to use
evaluate to some degree indirect and
cumulative impacts
• can be weighted/impacts ranked to
assist in evaluation

34
Source: modified from EC,
 EXAMPLE OF A SIMPLE MATRIX

Potential Proposed action

impact
Constructio Operatio Mitigation Other
area
n n Past present Future Cumulative
actions actions actions impact
Landscap * ** + * **
e
Ecology ** + * **
Water * ** **
quality
Land use *** *** * * ***
Cultural * ** * ***
heritage
*low adverse effect **moderate adverse effect ***high adverse effect
+ beneficial effect

35
Source: EC, 1999
Modeling
 An analytical tool which enables the quantification of cause-and-effect relationships
by simulating environmental conditions
 Application:
• a range of projects and environmental conditions
• predict impacts on specific physical environmental parameters (most), socio-
economic impacts (some)

Advantages Disadvantage
• quantifies cumulative impacts s
• often requires large investment of
• geographical and time-frame time and resources
boundaries are usually explicit • can be difficult to adapt some
• addresses specific cause-and-effect models to a particular project
relationships • depends on baseline data
available

36
Source: EC, 1999
AN EXAMPLE OF
MODELLING

37
Source: EC, 1999
 CASE STUDY

Alto Maipo Hydroelectric Project

Chile

Presented by: Lina Marcela Palomo

Garcés
38
 CONTENT

I. Location
II. Background
III. CIA stages
1. Scoping phase
2. Identification of the valued components of the ecosystem
3. Identification of existing projects
4. Cumulative effects
5. PHAM hydrology effects
6. Expeted cumulative effects
7. Cumulative effect management

39
 I. LOCATION

40
Source: ARCADIS, 2013a
 HYDRAULIC CONFIGURATION DIAGRAM OF PHAM

41
Source: EEA PHAM, 2013
 II. BACKGROUND

• EIA in Chile

• Cumulative impacts assesments (EEA)

• Public participation

• AES Gener

42
Source: EEA PHAM, 2013
 III. CIA STAGES

 i. Definition of scoping:

a. CVE identification
b. Identification of existing projects and the reasonably predictable future
c. Definition of spatial and temporal context
 ii. Organization and systematization of information

a. Affected environment and interrelations

b. Evaluation of cumulative effects and significance
 iii. Identiffication of effects
 iv. Evaluation
 v. Mitigation and monitoring management

43
Source: EEA PHAM, 2013
 SCOPING PHASE
Valued components of the
ecosystem

yes Is it no
important
?

Affected no
by
PHAM?

yes
Affected
no
by other
projects
?
yes

Includ Not
e in include
CIA in CIA

44
Source: ARCADIS, 2013b
 IDENTIFICATION OF THE VALUED COMPONENTS OF THE
ECOSYSTEM
- River continuity
- Biodiversity present in water courses
- Water courses flow
- Security in the availability of water for irrigation
- Surface water quality
- Recreational uses of water courses
- Sediment dynamics
- Social economic environment
- Local infrastructure, especially the routes Routes G-25 (El Volcán), G-345
(Río drawer Colorado) and G-455 (Yeso river drawer)
- Air quality
- Cultural and archaeological heritage
- Climate change
- Protected areas and / or of tourist, cultural or heritage interest
45
Source: ARCADIS, 2013b
 PRIORITY IDENTIFIED VALUED COMPONENTS OF THE
ECOSYSTEM

a) Superficial hydrology
b) Sediments dynamics
c) Landscape
d) Local community

Pictures from: Red Metropolitana

No Alto Maipo

46
Source: ARCADIS, 2013b
 IDENTIFICATION OF EXISTING PROJECTS

 Complejo Cordillera (AES Gener): Hydrolectric Power Plant Alfalfal I, Maitenes,

Queltehues and Volcán
 High Voltage Line Queltehues – Maitenes – Florida and associated substations (S/E
Queltehues, S/E Maitenes, S/E La Laja, S/E Florida)
 High Voltage Line Alfalfal – Los Almendros and S/E Alfalfal
 Hydroelectric Power Plant Guayacán (Energía Coyanco S.A.)
 Non-metallic mineral extraction and processing activities
 El Yeso Dam (Aguas Andinas) (1967)
 Laguna Negra Aqueduct (1917)

Picture from: Huincha, 2012

47
Source: EEA PHAM, 2013
 CUMULATIVE IMPACTS DURING PHAM CONSTRUCTION
PHASE

VCE´s Impact

PHAM Superficial Recreative Use

Hydrology Irrigation
Hydroelectri
c Projects
Human consumption
Water
Treatment Sediment Aggregate extraction
Projects Dynamics
Erosives processes
Mining
Projects Landscape Tourism

Local Road safety

Community
Basic services

Source: EEA PHAM, 2013 Cultural changes 48

 CUMULATIVE IMPACTS DURING PHAM OPERATIONAL PHASE

VCE´s Impact

PHAM Superficial Recreative Use

Hydrology Irrigation
Hydroelectri
c Projects
Human consumption
Water
Treatment Sediment Aggregate extraction
Projects Dynamics
Erosives processes
Mining
Projects Landscape Tourism

Local Road safety

Community
Basic services

Source: EEA PHAM, 2013 Cultural changes 49

 PHAM HYDROLOGY EFFECTS ON THE LENGTH OF THE
RIVERS
River Length Projects Distance Distance % % %
(Km) that affected affected Affected Affected Increment
affect it current by of the by ation of
projects Operation River by operation PHAM
s of PHAM current s of PHAM
projects
Maipo 108,7 CH 48,8 51,8 44,9 47,7 2,8
Queltehues
CH
Guayacán
El Yeso
Dam
Aqueduct
Laguna
Volcán 42,6 CH Volcán 14,0 22,3 32,9 52,3 19,4
Yeso 46,6 El Yeso 29,0 29,0 62,2 62,2 0,0
Dam
Aqueduct
Laguna
Colorado 56 CH 31,8 41,6 48,5 63,4 14,9
50
Source: EEA PHAM, 2013 Maitenes
SINGLE-LINE
DIAGRAM OF THE
UPPER MAIPO
RIVER BASIN PHAM
CONSTRUCTION
PHASE

Control point
Pluviometric control stations
Hydroelectric plant
Assessment
Extractions of Cumulative and Synergistic Impacts
Tributary streams 51
Source: APR Ingeniería S.A., 2012
Name
SINGLE-LINE
DIAGRAM OF THE
UPPER MAIPO
RIVER BASIN PHAM
OPERATION PHASE

52
Source: APR Ingeniería S.A., 2012
 EFFECTS OF PHAM ON THE RIVER FLOWS (ANNUAL
AVERAGES, M3 / S)
Control A scenario: B scenario: C scenario: D scenario: Adittional
point Before 1965 2012 Operationa effect
1917 l Phase compare to
PHAM the
scenario A
(%)
I 40,9 24,4 24,4 24,4 -40%
II 43,8 51,8 51,8 50,6 +17,58%
III 16,5 8,5 8,5 5,1 -29%
IV 13,0 11,1 10,8 4,0 -69%
V 87,2 85,2 63,7 54,6 -37%
VI 27,5 17,3 10,8 5,6 -80%
VII 32,4 32,1 32,1 12,2 -62%
VIII 119,6 117,3 117,5 82,6 -31%
53
Source: EEA PHAM, 2013
 Control A scenario: C scenario: D scenario: Comments
point Before 1917 2012 Operational Phase
PHAM
I 40,9 24,4 24,4 No impact from PHAM

II 43,8 51,8 50,6 Minor impact from

PHAM due to CH
Volcán
III 16,5 8,5 5,1 Impact from PHAM due
to reduction of flow
rates of Volcán river
IV 13,0 10,8 4,0 Impact from PHAM due
to reduction of flow
rates from Yeso river
V 87,2 63,7 54,6 Minor Impact in Maipo
River
VI 27,5 10,8 5,6 Impact from PHAM due
to reduction of flow
rates in Colorado River
VII 32,4 32,1 12,2 Impact from PHAM due
to reduction of flow
rates in Colorado River
VIII 119,6 117,5 82,6 Global Impact from
PHAM over Maipo river
54
Source: EEA PHAM, 2013
 IMPACT ASSESSMENT MATRIX OF CUMULATIVE IMPACTS
Impact Influenced by
PHAM Other Water Mining Significanc
hydroelectr treatment projects e
ic projects projects
Use of the x x x x (-) No
water: significance
Humane
consumption
Aggregate N/A x x x N/A
extraction

Erosive N/A x x N/A N/A

processes

55
Source: EEA PHAM, 2013
 CUMULATIVE IMPACTS MANAGEMENT
MITIGATION, REPAIR AND/OR COMPENSATION MEASURE FOR
CUMULATIVE IMPACTS
 Real-time monitoring of hydrology in the area of ​influence of the Project, which is
reported on the website of the General Water Directorate
 Development of studies on the effects of climate change on the basin
 PHAM Environmental Monitoring Plan, which incorporates the following
components during the construction and operation stages of the PHAM
 Monitoring of tourist use of the Maipo River
 Social Indicators monitoring program
 Monitoring of river and terrestrial biodiversity of the upper Maipo river basin

56
Source: EEA PHAM, 2013
 CONCLUSION
 Cumulative impacts can alter environmental systems through multiple pathways of
effect:
Growth Induced Pathway:
Each new project or action can induce further projects or actions to occur, sometimes
referred to as “spin-off” effects (e.g., an off-trail road resulting in increased hunting and
fishing)
Physical or Chemical Transport Pathway:
A physical or chemical constituent is transported away from the activity under review, where
it then interacts with another activity (e.g., air emissions, sedimentation, wastewater
effluent). Multiple point and non-point discharges of water pollutants are typical examples
Nibbling Loss Pathway:
This is the gradual disturbance and loss of land or habitat (e.g., clearing of land for a new
subdivision and new roads into a forested area
 For comprehensive cumulative impacts assessment, a mix of methods is appropriate
 The government and the companies should not underestimate the roll of the public
participation in the EIA/CIA process 57
 REFERENCES
Arctic Environment Protection Strategy 1997: Guidelines for Environmental Impact
Assessment (EIA) in the Arctic. Sustainable Development and Utilization. Finnish Ministry of
the Environment, Finiland, 50p
AES Gener, 2008a, Estudio de Impacto Ambiental de Proyecto Hidroeléctrico Alto Maipo.
AES Gener, 2008b, Adenda 1 al Estudio de Impacto Ambiental de Proyecto Hidroeléctrico Alto
Maipo.
APR Ingeniería S.A., 2012, Evaluación de Efectos Acumulativos, Hidrología y Dinámica de
Sedimentos, Revisión A, Febrero de 2012.
ARCADIS, 2013a, Informe No 4031-0000-MA-INF-001_F, “Tema 1: Identificación y Evaluación
de Impactos Potenciales sobre Usos y Usuarios del Agua”, junio de 2013.
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Informe Preliminar – Tema 2: Identificación y Evaluación de Impactos Potenciales en los
sedimentos”, enero de 2013.
CEQ (Council for Environmental Quality), Considering Cumulative Effects under the National
Environmental Policy Act

58
 REFERENCES
Eccleston, C. H., Environmental Impact Assessment: A Guide to Best Professional Practices,
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Huicha, 2012. https://huincha.wordpress.com/2012/09/25/embalse-el-yeso-san-jose-de-maipo/

59
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THANK YOU FOR YOUR ATTENTION!