Headwater and Intermittent Streams
Headwater streams are small streams that flow for the entire year and originate from groundwater. Intermittent streams are physically similar to headwater streams, but intermittent streams commonly dry up in the summer. These streams tend to be small and shallow (2-10 feet in width, 2-12 inches in depth) and contain a variety of microhabitats. Pools are deeper areas in streams where the water flows slowly. Riffles are shallow, rocky areas where the water tumbles quickly over rocks, and runs are areas where the surface of the water is smooth and the flow is moderately fast. The substrate of headwater streams is a mixture of various sized rocks and sand. The water tends to be cool and high in oxygen.
The streams at Teatown are home to a variety of animals including green frogs, two-lined salamanders, crayfish, fish such as black-nosed dace, and a variety of insects (called macro-invertebrates). Turtles such as spotted turtles and snapping turtles also use streams when they travel among wetlands and many birds and mammals depend on these streams as a source of food and water.
Conservation Issues
Headwater streams are under extreme pressure in the region due to the water demands of new development. As more homes are built in areas requiring the use of wells, some streams have dried up because the flow of groundwater has decreased. Streams are also subject to degradation due to development in their watersheds. Development increases the amount of impervious surfaces (surfaces that do not allow water infiltrate) resulting in increased runoff. The excess water introduced into streams carries with it pollutants from roads and residential areas such as lawns (pesticides and fertilizers). This excess water also does little for maintaining water levels in streams as it quickly enters and exits the stream during rainfall events. The dramatic increase in water inputs to streams during flood events also degrades streams by eroding their banks.
