Comparative study of analytical and numerical methods for estimation of aquifer parameters: A case study in Basaltic Terrain

Estimation (if aquifer parameters namely transmissivity (T) and storativity (S) are vital for the evaluation of groundwater resources. To estimate the accurate aquifer parameters, there are several methods (i.e. hydrograph analysis, pumping test, etc). In Asian and Southeast Asian countries large diameter wells are abundant and they are often cost-effective means to conduct pumping test as one can use the farmer's pump to perform this test. There are several suggested methods to estimate aquifer parameters through pumping test data, in which, curve matching and numerical methods are widely used. In this paper we have given special emphasis to pumping tests and data interpretation, which were carried out at 12 locations in a basaltic terrain at Belgaum city, Karnataka, India. The data is interpreted by using both analytical and numerical methods; and compared with them. The results of analytical methods have shown upto 35% error involved in the calculated drawdown as well as residual drawdown in comparison with the field observations, whereas it is less than 4.5% in the case of numerical method. Hence the present study shows that the numerical method is found to be more accurate than the analytical curve matching method for estimating the aquifer parameters.