Stream Habitat

Introduction

In-stream habitat data include measurements of a variety of physical and aquatic stream attributes that collectively reveal a great deal about stream condition for salmonids and trout. Characterizing and inventorying the physical conditions that define stream habitat for salmonids is an important part of the habitat restoration process. The California Department of Fish and Wildlife (CDFW) collects data on a number of physical attributes of streams and classifies these streams by one of several habitat types.

The in-stream habitat data collection process involves two distinct steps; identifying channel type and assigning a habitat type. These in-stream habitat data are used for a variety of purposes including analysis of stream suitability for supporting salmonid populations, as part of larger and more complex watershed assessments, and to establish baseline conditions against which future assessments can measure change.

They are a critical part of determining restoration priorities and identifying salmonid refugia. The California Salmonid Stream Habitat Restoration Manual, published by the CDFW, describes the process of using in-stream habitat data and other data and information for identifying streams with restoration potential and working through the stream restoration process.

In-Stream Habitat GIS Data

The in-stream habitat GIS data included in CalFish consist primarily of those collected by the CDFW beginning in the early 1990’s and extending through most of Humboldt and parts of Mendocino counties (see image to right). More recent data that was collected between 2010 and 2012 is available for Santa Barbara County. Other departments and organizations actively collect these data and as they become available, will be included in CalFish. In addition, historical in-stream data collected by the CDFW will posted to this site as funding for quality control and spatial treatment of the data become available.

CDFW Stream Inventory Reports

CDFW completes stream inventory reports to document the habitat conditions and recommend options for the potential enhancement of salmonid habitat for various streams at various times. Recommendations for habitat improvement activities are based upon target habitat values suitable for salmonids in California’s streams.

A subset of the complete collection of stream inventory reports is available from the CDFW Document Library. We hope to expand this collection to include new reports as they become available and to include reports from other areas of the state when possible. Read more about how to search for stream inventory reports in the CDFW Document Library.

Shelter Value Rating

One important parameter measured during the in-stream habitat assessment process is shelter value rating. This aggregate measurement is intended as an index of the quality and quantity of in-stream shelter for salmonids. Other important measurements include degree of embeddedness, canopy cover, and pool depth and frequency.