The screening process represents the first step within the evaluating process, in fact it drives along the interactive path of the E.I.A. procedure. It is not our aim to describe here entirely the way, but at least the principal guide line step by step. The methods of analysis don’t encompass every features of the evaluating process but they often fit a definite moment or fraction of the complete study.
You may surely understand the sequential program has to characterize the method, so that you clarify and evaluate carefully the method itself; It is absolutely needed to have the possibility of coming back to the beginning for analysing the node again.
We can resume briefly the screening process according to the following inferences.
a) setting of the analysis criterions and of the evaluation parameters
b) defining the planning choices fit the aims of the programme.
c) surrounding the lands influenced by the project
d) choosing the definite working methodology
e) understanding the degree of precision of the supplied documentation
f) establishing the rules of participation for the people living over the territory.
It is useful to distinguish between the possible choices of the arisen project and the choices concerning the project core. The first ones regard the decision to build or not to build the project and generally they come into the entire planning of the economic activities and of the social ones, and the second ones are referred to some different solutions after the making decision has been taken.
The beginning of this process constitutes the definition of choices of suitable projects and therefore it derives from the final steps of the screening.
The relations between the two phases (the screening and the scoping) could be stronger than ones could be thought by you as well as an organic analysis requires.
In first place we describe the building phase and its differences from other correlated steps, the ones latter presents the target of the analysis. In turn I would get the determination of the impacts within the building phase and within the utilization one.
The initial phase of building is quite different from the final principal phase named “use phase or utilization phase” because the nature of the impacts is typical, in fact the temporal features and the amplitude of the actions are mutable. The project may cause a local consequence or a wider influence over the neighbouring lands therefore we have to know thoroughly the environment for recognizing the possible hit point and the probable impacts. Within the “environment” we embed the ecosystems and the areas occupied by the mankind.
a) collecting knowledges as deeply as you may so you would avoid casual deficiencies.
b) organizing the data as best you will be able.
Because the impacts may cover variable extent so the analysis must be carried out considering a definite area where to localize the influence. Pursuing this aim we apply some mathematical instruments such as “check list” and “matrix targets-actions” and networks. The networks are a fundamental means to find out the basic impacts and the secondary ones time to time, on the other hand they have to gather the direct issues and the indirect ones. Another way for analysing the territory is represented by the overlapping maps, in my opinion this is the best route to make a correct analysis and nowadays it is always getting easier using the GIS technology already applied for some years. Balancing an action we refer to the modal influence as respects the surrounding territory and only in second place seek either a weaker or a stronger situation.
For appraising the signification the analyser has to fix a proper qualitative scale that could use a symbology to including the thoughts; the impacts may arrise with different sign, it might be positive or negative and they show reversible character or irreversible one.
The impacts are generally a “pure footprint” because of the occurred difficulty to foresee exactly the interactions among the factors set in the environment and in particular how these factors will evolve. The”dirty impact” takes on the future evolution of the environment getting started from the actual scenery. The “pure footprint” derives from the “dirty impact” minus the value assigned to the “zero point” which corresponds to the existing situation. The “pure footprint”, called also the “pure impact”, is the only measurable to program an arrangement.
The factors must be as simple as you may choose on the other hand they have to declare their conciseness in fact too many data determine a complex calculative procedure and the further decision one. The qualitative scale ought to be used every time the factor shows an appreciable internal uncertainty, in this case you won’t have to assume a quantitative scale because it would introduce an additional element of contradiction.
The “red flags” are the “warning borders” of the modified targets therefore it is very important we watch and compare them with the probable evolution leading to the dirty impact. The criterions encompass wholly and focus the crucial point that are gathered into the specific area. You should understand how it is essential to give a correct value to every criterion and it is possible only when the relations among them have been clarified without a doubt so that the details have to emerge.
The appraisal may take place when the resources are comparable and compensable. This aim is reached every time the analyser finds the three principal characters beneath compiled.
a) the resources have to achieve a fixed rate of substitution among themselves.
b) the preferences have to be independent, in other words they musn’t present a double count.
c) the negative effects must be compensable through the positive one.
You all will understand how the points here above are not always kept making an environmental evaluation because of the typicality of the criterions, for example their rarity and their weakness so the aggregation of impacts is really a great problem.