A comparison of four methods to estimate groundwater recharge for northeastern South Dakota.

摘要

The rate of groundwater recharge is one of the most important elements in the analysis and management of groundwater resources. In addition, it is also the most difficult quantity to determine. This thesis, which is the result of a study made in northeastern South Dakota, presents an overview of four methods for estimating groundwater recharge, including an evaluation of the accuracy and suitability of each. These methods are the soil water balance, Chaturvedi formula, seasonal recession method (Meyboom method), and the well level data. Furthermore, this study seeks to find a selection of methods best suited based on climate classification. The soil water balance method and the well level data method appeared to be more efficient for the study area where the climate is sub humid continental. On the other hand, the Chaturvedi formula and Meyboom method are more efficient in tropical regions. Climate data was used for the calculation of the soil water balance and Chaturvedi formula while streamflow data was used in the Meyboom method. For the well level data method, observation well data was used. Every method has advantages and disadvantages. However, in order to have an accurate estimation of groundwater recharge, a variety of methods may have to be used. The soil water balance had the best fit when it was compared with the well level data method. The Chaturvedi formula and Meyboom method did not allow negative values; therefore, there were not a good fit compared with the well level data method.