4. Urban hydrology and well being
4.5 ENVIRONMENTAL IMPACT ASSESSMENT
At this point, it is important to shift attention from a broad description of the urban ecosystem and its characteristics to the related question of assessing and evaluating effects resulting from changes with or without any particular intervention. To guide our thinking the sequence of argument as outlined in 4.5 is shown diagrammatically in Figure 4.7.
38
Environmental impact assessment
Stress/intervention/change
(analysis) (Chapter 1.3)
assessment (Chapter 4)
(evaluation) (Chapter 5)
process of assessment
I
central concern : methodological attempts for measuring impacts and consequences
I
purpose of environmental impact assessment : generate a 'dynamic' model
1
applicability of environmental impact assessment Figure 4.7. Sequence of argument in section 4.5
4.5.1 Urban stresses and the environment
Environmental impact assessment, diagrammatically expressed in Figure 4.8, generally involves a contrast between present ambient conditions and probable, or desirable, future states and the range of effects and alternatives resulting from implementation of a particular action.
In other words, environmental impact assessment can be broadly understood to b e an appraisal of short- and long-range consequences of technological change on all surrounding environments.
range of effects
/ /
Future states
\
\
/
analysis -I L
assessment
J L
evaluation
Figure 4.8. Diagrammatic expression of environmental impact assessment
In this respect, three different elements bring together the argument throughout this work:
1. Chapters 1-3 (and part of Chapter 4) attempted to provide a basic understanding of the dimensions of the problem {analysis);
Environmental impact assessment
2. The present section concentrates on the meaning and significance of the process of assessment; and
3. Following sections will elaborate the process of evaluation, or the passing of judgement and decision-making.
The coming of a new technology, a development, or change affects the complex urban system over a period of time by setting into motion a variety of cause-effect-cause chains and by triggering an interrelated, interacting system of impacts and consequences which through feedback mechanisms may permit among others:
1. The creation of new economic and environmental conditions 2. The demand for new or different services
3. The establishment of required institutional responses to the changing circumstances
4. Changes in the overall quality of life on a given community and in corresponding attitudes and values
5. The generation of a 'multiplier effect, facilitating further growth, expansion and the creation of a new set of socio-economic and
environmental conditions.
There are several obstacles to the selection of a list of indicators. Since urban processes may be regarded in the light of the concept of an ecosystem, a study of social and economic changes apparently cannot be undertaken without due consideration of interferences with, for instance, the physical environment. So we have to take into consideration inter-actions in a more widely perceived environment. This is already in practice in those studies that are called 'environmental impact assessment'. Such an approach may, in some way, be regarded as a variant of what is called 'consequence analysis'. This kind of analysis may, in some respect, be regarded as a fourth step in a model development that consists of an input, a throughput and an output. The consequence analysis aims at examining the consequences of the output due to existing constraints of different natures etc. It may be noted that the idea of consequence analysis originally stems from man's experiences from adverse effects due to his environmental activities.
With this approach in mind it would be appropriate to make some definitions. We may state that man's actions cause environmental effects which produce environmental impacts. In such a line of thought, man's actions will encompass legislative proposals, policies,
programmes, projects and operational procedures in a manner that has already been commented on.
An environmental effect is generally defined as a process that will put in motion, or will be accelerated, by man's actions. Such an effect could for instance be the erosion of soil, the dispersion of pollutant, or the displacement of persons; all due to urban activities. By the environmental impact could be meant the net changes which may be regarded as good or bad for man's health and well-being. With the above text in mind, it is important to include the well-being of the ecosystem on which man's survival depends (Munn, 1975). Those net changes are the expected results from an environmental effect and they are related to changes in the quality of the environment, if we regard it as unaffected by man or under the influence of man's activity.
An environmental impact assessment should include four items relating to general environmental effects, namely:
1. Determination of the initial reference state (ambient conditions) 2. An estimate of the future state 'without action'
3. An estimate of the future state 'with action' 4. Criteria for assessment and evaluation.
40
Environmental impact assessment
Since one of the most important goals of this report on socio-economic aspects of urban hydrology is to pay special attention to the impacts of water-related urban activities on the
(physical) environment, it is important to elucidate how to look upon the quality of the environment. One way of approaching this quality problem would be to formulate the conditions for making this quality of the environment as large as possible. This could be expressed by stating that the objection function could be of the following type:
d (QOE) = I a. dG. - I a dB •+ max (4.4)
. 1 1 s s
i s
In this expression QOE represents an index of environmental quality which may be composed of the difference of weighted positive (good) and negative (bad) components represented by
dGj_ (i = 1, ... 1) and dBs (s = 1, . . . S) respectively. The parameters a^ and as are relative weight coefficients. The bad components are those which are of special concern in this case.
They are connected to human action as well as to the biosphere by a set of S balance equations of the following type (Unesco, 1973).
dB = E - P + H - R (4.5) s s s s s
where
E = amount of 'bad' s emitted s
P = amount destroyed by human action H = amount created by biosphere R = amount destroyed by biosphere
It is now possible to relate the variables included in equation 4.5 to two other social, economic and ecological variables by a relationship of the following kind, say
E = Z e . G.
s si i i
where
e . = amount of bad s produced when one unit of good i is produced
We may also form a set of equations which take account of the cleaning activities Pm
(m = 1, ... M) responsible for destroying at least part of the negation impulses of economic actions P . This relationship may be expressed in the following way:
P = I c P (4.6) s sm m
m
The coefficients cs m as well as the relationship shown in equation 4.6 may be implemented from engineering information. Research results could be introduced into the model presented by the variables Hs and Rs, by linking the net influence of the environment to a function of certain natural features Wk (k = 1, ..., K) of the biosphere. This gives the relationship
(4.7)
H •
s - R = E d , W s sk k
K
where d are some 'weight' factors.
Besides these relationships we may postulate some critferion of environmental quality standards. This criterion could then limit the amount of good activities and maximize the amount of bad activities. Those conditions could be expressed as
dG. £ Q. (4.8a)
d Bs £ Q (4.8b)
In addition we need to consider the physical resources available, a condition which could be expressed as
Environmental impact assessment
Z b P + Z b . d G . < M (4.9) rm m ri i v r
m i where
M = amount of resources available during the period under consideration
b = relative amounts of the resource necessary for activities m at the unit level
b . = relative amounts of the resource necessary for activities i ri
at the unit level
The crucial point in the above analysis is of course the fact that effects of water activities alone may be very difficult to separate from secondary effects (chain reactions).
4.5.2 Purpose of environmental impact assessment
While environmental impact assessment has become a formalized procedure in only a few countries, the basic principles are useful as a methodological approach to a systematic analysis of the consequences of technological change.
The purpose of an environmental impact assessment must be clarified as far as possible.
Short time as well as long time consequences should be thoroughly contemplated. As a starting point it could be asked if the greatest long-term benefits of well-being are possible only if the natural environment is maintained in a condition as close as possible to that existent before the world population explosion and industrial revolution.
However, not all interventions in the environment are necessarily adverse or have negative spillovers. A number of actions must be taken to guarantee survival and common welfare. Also, our appreciation of effects is limited by our present state of knowledge.
As Munn (1975) and others explain in the context of the requirements provided by the National Environmental Protection Act of 1970 in the USA, an environmental impact assessment should contain:
1. A description of proposed actions together with alternatives.
These alternatives may include one to the effect that no action at all will be undertaken;
2. Predict the nature and magnitude of the environmental effects;
3. Identify the relevant human concerns;
4. List the impact indicators to be used. For each of these we have to define its magnitude and for the total set we have to define the weights to be assigned to each indicators as obtained from the de ci s i on-maker or national goals;
5. From the predicted values of the environmental effects deduced above under (2), determine the values of each of the impact indicators and moreover the total environmental impact;
6. Then it is necessary to make recommendations for one of the following:
(a) acceptance of the project (b) remedial action
(c) acceptance of one or more alternatives (d) rejection
7. Finally, recommendations should be made for inspection procedures to be followed after the action has been completed.
42
Environmental impact assessment
It may be advisable to have a general model of the process by which plans lead to socio-economic impacts. This model should be considered in order to take into account the complexity of a series of otherwise unforeseen interactions which may occur before the ultimate
implementation of a plan.
A simple example may suffice to show how chain reactions, or cause-effect-cause chains, make a system dynamic (Fitzsimmons, Stuart and Wolff, 1975):
1. The project alters water availability.
2. New economic and environmental conditions are developed.
3. Change in economic opportunities affects existing population groups differently and attracts new residents.
4. New residents bring new values which may conflict with those of the existing population.
5. New people demand more and perhaps different services.
6. Institutions must respond in new ways.
7. Changes occur in the quality of life and in community and values.
8. Changed conditions, in turn, may attract new outside investments, and so forth.
Moreover, the so-called 'dynamic systems model1 which is of great use in impact assessment studies may have the following properties:
1. Such a model allows for consideration of various influences acting upon a system. Plans for alternative water development projects are examples.
2. This approach also allows one to consider other sources of influence upon the system (exogenous variables), such as changes in the resources and values of the larger society, which may interact with the implementation of the plan.
3. The approach allows one to form ideas about the system - its communities and residents - in terms of a complex of present-day characteristics.
This implies that, in part, the effects of a plan are contingent upon the nature of the community being affected.
4. Changes taking place in the system are viewed in terms of distribution over space, over time, among many groups, and of being valued
differently by different people.
5. Changes are viewed as both a direct and an indirect result of the implementation of the plan. This occurs as a result of interactions set into motion among persons, groups, organizations, and new demands placed upon institutions. These are complex and involve many cause-effect-cause chains over time.
6. Changes which occur will, in fact, encompass a variety of beneficial and adverse effects, and the ultimate recommendation of a given plan will involve judgements about the value of a variety of trade-offs of good and bad effects.
4.5.3 Applicability of environmental impact assessment
As stated above, the purpose of environmental impact assessment is to appraise the effects of technological action on the surrounding environments as part of integrated, long-range planning.
Environmental impact assessment
In its broadest terms, assessment becomes a procedure for analysing and predicting effects of purposive action and, thereby, forestalling, or reversing, adverse consequences to which a particular project may give rise.
The final task of environmental impact assessment must include someone's evaluation of perceived effects and, thus, provide the basis for informed decision-making. This point of evaluation is discussed in the next chapter. We conclude here, with some general remarks as to the potential applicability and ultimate utility of environmental impact assessment. It can help the decision-maker to:
1. Examine community changes through comparisons of alternative versions of a project;
2. Consider various impacts in terms of benefits and liabilities for different community groups;
3. Provide a means for organizing, comparing and delineating lots of criteria in a variety of urban hydrological situations;
4. Establish a basis for examining the relationship between short-term impacts and long-range consequences;
5. Balance the results of environmental considerations against technical, economic and social costs and benefits;
6. Integrate technological considerations and physical solutions with non-structural alternatives in social sciences;
7. Create a background for informed decision-making compatible with the aspirations of the people.
In essence, such selective considerations reinforce a general approach that attempts to provide an objective framework for analysing urban processes so that the underlying logic and process can be followed by all parties concerned.
The process of environmental impact assessment is currently evolving rapidly.
Currently, a number of basic works exist on the general topic, with special emphasis on conceptual premises and methodological strategies. A selected list of studies and
commentaries is given in Appendix 2. It should be noted that in the field ofvurban hydrology little work has been published, although a number of publications on impact of water projects are useful for their approach to the subject.
44