Water science news, explainers, and statistics covering freshwater, hydrology, lakes, rivers, groundwater, ice, and Earth’s connected water systems.
A gaining stream receives groundwater through its bed or banks, while a losing stream sends water downward into the surrounding aquifer. The direction is controlled mainly by the relative elevation of the stream surface and the local groundwater level. One river can gain in an upstream reach yet lose farther down. Seasonal water levels or…
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A groundwater well is a constructed opening that reaches saturated soil or rock and allows water to enter a casing. A pump usually lifts that water to the surface. The well does not create groundwater or draw from an underground pipe; it intercepts an aquifer and changes the local flow toward its intake. Reliable production…
Saltwater intrusion occurs when saline water enters a freshwater aquifer and makes part of its supply less useful. It is most familiar near coasts, where fresh groundwater meets seawater, but deep saline groundwater and human-made sources of salt can also affect wells. Coastal pumping is the leading driver. Lowering freshwater pressure allows the transition zone…
Groundwater depletion is a sustained loss of water from an aquifer when withdrawals exceed the water that replaces them. A falling well level is the most familiar sign, but depletion can also reduce streamflow, increase pumping costs, compact sediments and draw poorer-quality water toward supply wells. The problem is about long-term storage rather than one…
