| Groundwater-surface water interactions (GSWI's) interactions are an important part of understanding the hydrological cycle, groundwater and river systems, and in providing estimates of groundwater contributions to rivers (base flow). Seepage/leakage of groundwater into surface waters can be measured directly, but this is very labor-intensive, and therefore not feasible at the scale of a basin. An alternative method, which was used in this study, infers groundwater seepage from electrical conductivity and temperature (EC& T) of water at the bottom of the river, based on the assumption that there is a contrast between the incoming groundwater and the river water (which is almost always the case).; Zones of groundwater seepage were confirmed and quantified using open-top seepage meters. The results were then used to obtain an integrated baseflow and compared to baseflow found from graphical hydrograph separation techniques. Baseflow estimates, using the two methods, were similar.; The methodology in this study proved useful in detecting groundwater seepage, but it was also efficient at pinpointing sources of local high EC loading in the river. This can therefore be an extremely valuable tool in the watershed management. The level of detail proved by this method is extremely useful in many GIS-based applications, including the assessment of susceptibility of an aquifer to contamination, the understanding of a river ecosystem, flood protection and control and groundwater modeling exercises. |
