The problems that arise are: o Uncertainty about the actual system response to the impact generated by the project. You can estimate the answer but sometimes it is difficult to determine what the actual behavior of the system to change. o Lack of information about the project or strong deviations from it which may be significant in determining the overall impact of it. To quantify the impacts arise somehow impact indicators, which have to be: o Relevant. or reliable.
Representatives of the impact to be measured. Exclusive, ie that its value mainly involved measuring the impact and other factors. or completed. Identifiable and measurable (although the fact should not be obsessed quantify everything, because you can always go to categories semiquantitative or qualitative measures) Impact indicators can be designed with two approaches: either Reductionist (Simple: Temperature, pH, concentration of pollutants, floor area, etc.).. Disadvantages: high number of variables which leads to a high number of indicators and difficult to synthesise the impacts when the overall assessment. Advantages: simple, easy to measure.
or Holistic (structural indices: Diversity, Wealth, P / B, Complexity food webs, species abundance curve, etc.).. Disadvantages: dilution effects on global indicators mask important impacts. Advantages: indices with a very synthetic nature. Impact assessment methodology. A. Identification of project activities: – To amend the land use. – To exploit natural resources. – That emit contaminants. – To induce secondary impacts. – To induce natural hazards. B. Identification of factors in the MA susceptible. – Indicators of impact. – Indices of structure.