A stream that ﬂows seasonally when the water table is high, such as during and after periods of heavy or steady rain, is called intermittent. Such streams may be connected with natural reservoirs in hills or mountains. When the reservoir exceeds maximum holding capacity, water spills over the rim and siphons down toward lower ground. This ﬂow ceases when water levels fall below the reservoir rim. During the dry summer months, intermittent streams may cease to ﬂow, causing the channels to appear dry, although in fact water continues to travel through the stream bottom or underground. At the height of ﬂow, intermittent streams may temporarily ﬁll dry lakebeds in desert regions to form bodies of water called playa lakes. Sometimes intermittent stream is used as a synonym for ephemeral stream.