Water resources and hydrological management (original) (raw)

2017, International Encyclopedia of Geography

Water resources refer to surface waters that flow across the land and groundwater that percolates beneath the surface, which are subject to various types of human activities and hydrological management (i.e., human measurement, use, modification, and control). Key hydrologic processes in the water cycle include precipitation as snow and rain, interception of rainfall by plants, infiltration into soil surfaces, evaporation and transpiration by plants, snowmelt and runoff of these fresh waters into streams, lakes, and wetlands, along with erosion and sedimentation of those surface water bodies, recharge of groundwater aquifers, and ultimately discharge into saline coastal waters (Figure 1). Hydrology has close relationships with climatology, glaciology, geomorphology, and oceanography. Each hydrologic process is shaped by regional interactions between the Earth's energy budget, climate, landforms, and land uses which themselves range from forests to grasslands, croplands, industrial areas, and urbanizing landscapes. Each of these types of human settlement modifies hydrologic processes in ways that affect water quantity, quality, and use. Although the distribution and flows of water resources change in dynamic ways, water is not lost from Earth's hydrologic cycle. It remains as part of the world water balance. Human activities convert hydrologic processes into "resources" that serve various social purposes. Water resources are therefore defined The International Encyclopedia of Geography.