Recharge of springs
Knowledge of groundwater systems is a basic prerequisite for the efficient management of springs. The relationship between groundwater recharge and discharge is one of the most important aspects in the protection of groundwater resources. Groundwater and surface water are fundamentally interconnected. It is therefore often difficult to separate the two, because they recharge each other, and hence they can also contaminate each other. Recharge of groundwater may occur naturally from precipitation, surface streams and lakes, and as an anthropogenic input from irrigation and urbanization. Two types of recharge are generally distinguished: direct and indirect recharge. Direct recharge is the water added to the aquifer in excess of soil moisture deficits and evapotranspiration, by direct vertical percolation of precipitation through the unsaturated zone. Indirect recharge results from percolation to the water table following runoff and localization in joints, as ponding in low-lying areas and lakes, or through the beds of surface watercourses. The combined use of various geochemical and hydrologic tools can considerably enhance the understanding of complex groundwater flow patterns as well as the mixing of groundwater and surface water in a particular spring. Movement of water in the atmosphere and on the land surface is relatively easy to visualize, while this not the case for the movement of groundwater. Groundwater flow paths vary greatly in length, depth, and travel time from the recharge areas to discharge areas and springs. These indicate that successful groundwater recharge estimation primarily depends on identifying the probable flow mechanisms and important features that influence the recharge for a given locality.