MODELING THE OPITMAL CONFIGURATIONS FOR RADIAL COLLECTOR WELLS TO AID IN RIVERBANK FILTRATION

By placing the wells in close proximity to the river, the pumped water would invariably flow through the riverbed and aquifer materials thus removing potential contaminants. This is known as riverbank filtration. It has also been found that by combining this filtration method with collector wells that not only can contaminants be removed, but also a large amount of groundwater can be pumped without deleterious effects to the aquifer. A collector well consists of essentially several horizontal wells (laterals) connected to a vertical cylindrical caisson which are arranged radially around it. There are still many questions unanswered as to what configurations are best for optimal groundwater extraction with the collector wells. There are several parameters that are needed to be tested and considered: the number of laterals to use, the diameter of the laterals, the length of the laterals, the lateral design, and the distance of the collector well to the river. Currently, there are few guidelines regarding the best application of collector wells for riverbank filtration. The purpose of this study is to utilize MODFLOW to model different configurations for shallow, intermediate, and deep rivers, considering rather realistic riverbank sediments. The focus is on testing various parameters on the hydrodynamic performance of a collector well. After analyzing the modeling results, we will provide guidelines and recommendations for employing collector wells for riverbank filtration.