Headwater streams are the small swales, creeks and streams that are the origin of most rivers. These small streams join together to form larger streams and rivers or run directly into larger streams and lakes. Streams may be home to small fish, amphibians and invertebrates.
Streams can be ephemeral, intermittent or perennial. Ephemeral streams are those that contain flowing water only after major rain events or for very short times during the year. Intermittent streams flow only during the wetter periods of the year. Perennial streams contain water year-round. The collective health and functioning of the stream network have profound influences on the quality and value of larger streams, rivers and lakes.
Compensatory stream mitigation may be required for impacts to streams and should be designed to restore, enhance, and maintain stream uses that are adversely impacted by authorized activities.
- Streamflow Duration Assessment Method: The Streamflow Duration Assessment Method (SDAM) for the Pacific Northwest is a scientific, rapid-assessment field tool developed to help determine whether a stream is perennial, intermittent or ephemeral.
- A stream mitigation plan must include the elements of a mitigation as required by the Federal Mitigation Rule as excerpted in this document entitled Components of a Mitigation Plan per the Final Rule. In particular, please note item 7.
- To ensure impacts are minimized and appropriate techniques are implemented, please utilize the Integrated Streambank Protection Guidelines published by the Washington State Department of Fish and Wildlife.