Environmental Eng. 1 (CE 360)
Dr. Sameh S. Ahmed
Associate Professor of Environmental Eng.
Civil Engineering Department
Engineering College
Majma’ah University
s.mohamed@mu.edu.sa
faculty.mu.edu.sa/smohamed/SaMeH
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Chapter 3
Assessing Environmental Impact
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Introduction
Environmental engineering requires that the impact and
interaction of engineered structures on and with the
natural environment be considered in any project.
It is a must that , environmental impact be assessed
whenever a federal action will have an environmental
impact, as well as alternatives have to be considered.
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Step-by Step Approach
Engineers ideally approach a problem in a sequence:
(1) Problem definition
(2) Generation of alternative solutions
(3) Evaluation of alternatives,
(4) Implementation of a selected solution, and
(5) Review and appropriate revision of the implemented
solution.
This step-by step approach is essentially for most of Environmental
assessment.
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Environmental Impact
• Definition:
Possible
adverse
effects
caused
by
a development, industrial, or infrastructural project or
by the release of a substance in the environment.
Environmental law in USA states that: each project
funded by federal government or requiring a federal
permit must be accompanied by an environmental
assessment.
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Environmental Assessment
Assessment ends with issuing one of the following
documents:
(1) Finding of No Significant Impact (FONSI).
(2) Environmental Assessment (EA).
(3) Environmental Impact Statement (EIS).
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Assessment
EA
EIS
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FONSI
FONSI
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Environmental Assessment
(1) Finding Of No Significant Impact (FONSI).
Such a stand-alone finding results when potential
environmental impacts are compared to a checklist of
significant impacts, with the result that no significant
impact can be identified.
(2) Environmental Assessment (EA).
A detailed assessment of potential environmental impact
resulting in one of two conclusions: either the EA must
be expanded to a full-scale environmental impact
statement or a FONSI results from the EA.
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Environmental Assessment
(3) Environmental Impact Statement (EIS).
An EIS must assess in detail the potential environmental
impacts of a proposed action and alternative actions.
Additionally, the agencies must generally follow a
detailed public review of each EIS before proceeding
with the project or permit. It should be noted that both
positive and negative impacts are included; i.e.,
“impact” does not imply “adverse impact.”
These impact statements are assessments and contain no judgments
about the positive or negative value of the project in question.
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EIS
(EIS):
An EIS publication sequence is prescribed by law.
1. First, a Draft EIS (DEIS) is issued by the appropriate federal
agency.
2. After mandated public hearings and incorporation of comments,
the federal agency issues a Final EIS (FEIS).
3. A Record Of Decision (ROD), which includes the final decision
about the project, the alternative chosen, and any value
judgments, is also issued.
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Purpose of EIS
The purpose of environmental assessments was not to
justify or fault projects, but to introduce environmental
factors into the decision-making machinery and have
them discussed in public before decisions about a
project are made.
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Assessment of Socioeconomic Impact
As the environmental assessment procedure has evolved,
assessment of socioeconomic impact of the project has
played an increasing role.
In addition to direct economic impact (number of jobs,
total household income, property values, etc.),
socioeconomic impact includes impacts on:
• archaeological and historical sites,
• sites that have cultural significance
• on cultural practices, and environmental justice
impacts.
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Environmental Inventories
The first step in evaluating the environmental impact of a
project’s alternatives is to inventory factors that may be
affected by the proposed action.
Existing conditions are measured and described, but no
effort is made to assess the importance of a variable.
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(Cont.)
Any number and many kinds of variables may be included,
such as:
1. the “ologies”: hydrology, geology, climatology, and
archaeology;
2. environmental quality: land, surface and subsurface water, air,
noise, and transportation impacts;
3. plant and animal life;
4. economic impact on the surrounding community: number of
jobs, average family income, etc.;
5. analysis of the risks to both people and the natural environment
from accidents that may occur during the life of the project; and
6. other relevant socioeconomic parameters, like future land use,
expansion or diminution of the population of urban areas
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Environmental Assessment
The process of calculating projected effects that a
proposed action or construction project will have on
environmental quality is called environmental assessment.
A methodical, reproducible, and reasonable method is
needed to evaluate both the effect of the proposed project
and the effects of alternatives that may achieve the same
ends but that may have different environmental impacts.
Methods:
Checklist, the interaction matrix, and the checklist with
weighted rankings.
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a) Checklists
Checklists are lists of potential environmental impacts,
both primary and secondary.
•
•
•
Primary effects occur as a direct result of the proposed project,
such as the effect of a dam on aquatic life.
Secondary effects occur as an indirect result of the action.
For example, an interchange for a highway may not directly
affect wildlife, but indirectly it will draw such establishments as
service stations and quick food stores, thus changing land use
patterns.
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a) Checklists (cont.)
The checklist for a highway project could be divided into three
phases: planning, construction, and operation. During planning,
consideration is given to the environmental effects of the highway
route and the acquisition and condemnation of property.
•
•
The construction phase checklist will include displacement of
people, noise, soil erosion, air and water pollution, and energy
use.
Finally, the operation phase will list direct impacts owing to
noise, water pollution resulting from runoff, energy use, etc., and
indirect impacts owing to regional development, housing,
lifestyle, and economic development.
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a) Checklists (cont.)
The checklist technique thus lists all of the related factors; then the
magnitude and importance of the impacts are estimated. Estimated
importance of impact may be quantified by establishing an arbitrary
scale, such as:
0 = no impact
1 = minimal impact
2 = small impact
3 = moderate impact
4 = significant impact
5 = severe impact
The numbers may then be combined, and a quantitative
measurement of the severity of the environmental impact for any
given alternative be estimated.
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