Forest Streams

Streams add diversity, beauty and interest to forested properties and are a vital resource to California's people and wildlife. Forests are sources of drinking water for people throughout California. Streams and the riparian vegetation associated with it supply important habitat for many species of aquatic and terrestrial wildlife. Improving management of forest streams is becoming increasingly important in the endangerment many California fish species, especially salmonids.

Stream Channels

Stream channels form as a means of transporting water, sediment and wood from forested headwaters downhill. Channels develop and wildlife has evolved to adapt to this dynamic environment. Many forest streams have been impaired by previous practices including dredging, dams, straightening, mining, and road crossings. Currently, modification of stream channels is heavily regulated in California, but many legacy impacts exist that can be mitigated by stream management practices or active restoration.

 

Riparian Vegetation

A key to maintaining healthy stream channels is to protect and enhance the riparian vegetation growing along it. Riparian vegetation performs important ecological functions including serving as terrestrial and aquatic habitat, stabilizing stream banks, providing shade and large woody debris that adds complexity to stream beds to improve fish habitat. Removal of this vegetation can trigger degradation and instability of streams leading to erosion and washing away of stream side property. Maintenance of buffer strips where no development occurs next to stream channels is one of the best ways to protect riparian vegetation and is required when many projects including timber harvest are done.

 

Water Quality

Since forest management and other land use activities have impacts on water quality, it is important to understand what water quality is, how it is measured and how to protect it. The quality of water coming from forest lands is vital for human use, but also for sustaining aquatic life, irrigation, swimming and recreation, navigation and hydropower generation. Water quality indicators include clarity (turbidity), chemical content (pesticides, nutrients, petroleum products etc), bacterial content and temperature (in relation to the tolerance levels of aquatic organisms).

 

Fish and Fish Habitat

Special care must be taken when managing forest streams that are habitat or potential habitat for salmonids - fish in the salmon and trout families. Most of these fish require stream habitat with year round water temperatures below 68 degrees Farenheit, high levels of dissolved oxygen, clear water, and a stony or gravelly substrate. They have a complicated life cycle which involves emerging from nests and growing in fresh water streams, migrating to the ocean to grow large and returning to their natal streams to spawn. Forest management actions that can impede this life cycle include activities that cause erosion, remove water, simplify channels and remove riparian vegetation or create barriers to migration. Many salmonid species in California are threatened or endangered and so particular care is needed to maintain and restore their channel habitat.