Stream Habitat


Stream habitat is one of the important factors that affect aquatic communities. Stream habitat describes the quality of the place or environment where wildlife live.

In Montgomery County, poor habitat is usually the most likely cause of a lack of aquatic species diversity, poor health, and decreased population sizes. Degraded in-stream habitat often results from uncontrolled storm water runoff and uncontrolled runoff from intensively grazed or cultivated agricultural land.

Other reasons for poor stream habitat include altered stream flows, excess sediment, and a loss of surrounding trees and shrubs that help slow the erosion of the stream. Chemicals and pollutants also negatively impact stream habitat.


Image of an excellent condition stream.

How does stream habitat affect the aquatic community and the environment?

Stream habitat affects the aquatic community in many ways.

  • Too much sediment can smother bottom living organisms and communities by filling in the spaces between the stream bed material that the aquatic community needs for respiration and habitat space.

  • Lack of stream cover can impact the fish community by removing places for them to hide and rest.

  • Lack of clean stream gravel, clean running water and small pools removes places aquatic organisms need for egg laying and for nurseries for small fish fry.

  • Lack of riffles, pools and runs can impact separate life stages of aquatic organisms.

  • Murky, cloudy water prevents fish from seeing their food.

  • Too much sediment can cover the gills of aquatic insects affecting their ability to respire‚Äč

In addition to habitat conditions in the stream, the condition of the adjacent stream banks and stream valley also affect the aquatic community. Some of the problems in the stream valley and stream bank include:

  • Uncontrolled access by agricultural animals into the stream causing siltation and muddy conditions.

  • Lack of trees on the bank to provide shade for cooler water conditions.

  • Stream bank erosion caused by mowing up to the edge of the stream.

Stream habitat is monitored by the DEP every time a stream is monitored for either aquatic insects or fish.



Requests for Data

Interested in accessing Montgomery County's biological or stream habitat data?  Individuals and groups can file a request for data by contacting the Department of Environmental Protection.