A stream which ceases to flow in very dry periods. The flow may occur when the water-table is seasonally high, but there will not be flow when the water-table is significantly below the river-channel bed level. One view of the drainage network (see drainage pattern) is that it is made up of perennial streams, which flow all the time, intermittent streams, which flow when the water-table is seasonally high, and ephemeral streams, which flow only during storm conditions. Such streams tend to have permeable beds and discharge leaking through their beds (transmission losses) is added to the local groundwater. The chalk bournes of southern England are special types of intermittent streams. See also losing stream.
Subjects: Ecology and Conservation.