It may be expedient to develop a listing of known standards during the initial CHIA in order to reduce the time it takes to prepare subsequent assessments. In addition to the existing standards that may be fairly general in scope, the RA should consider developing material damage standards for specific parameters that generally reflect mining impacts such as iron, manganese, sulfate, and total dissolved solids, as well as parameters of local significance to water use. Empirical equations and statistical correlations. Physical process models of the hydrologic system. Qualitative methods rely heavily on the experience and qualifications of the user and minimize the need for numerical calculations.
Results are more general in content and require less detailed information than quantitative methods.
On the other hand, quantitative methods include a variety of numerical analyses, some fairly simple, while others may involve very complex calculations requiring large amounts of data. Qualitative and quantitative methods may vary greatly in information requirements and cost per analysis. The RA should consider the accuracy and precision needed for a particular impact analysis, the information available for the CIA, the number of permits to be approved, and the time and resources available to do the analysis. While quantitative methods may be more precise than qualitative methods, this does not guarantee greater prediction accuracy. Also, as discussed for PHC strategies earlier, high precision will not be warranted for CHIA assessments in all cases.