Water Quality Division

Assessment of Stream Habitat

As important to the overall aquatic health of a system is the habitat available for aquatic organisms. Some streams have adequate water quality, but poor habitat limits the type of organisms that live in the stream. Therefore, habitat measurements are collected at least twice a year to characterize the type of habitat available. More frequent measurements may be necessary in less stable stream types. Standard parameters measured during habitat evaluations include:

• stream flow,
• channel sinuosity,
• distance of the measured segment,
• depth of water,
• water width,
• bank width,
• embeddedness (amount of sand, silt or clay deposited in rifles),
• substrate type (sand, silt, clay, cobble, gravel, bedrock, etc.),
• habitat type (riffle, pool, run),
• amount and type of instream cover,
• percent canopy cover,
• presence or absence of point bars,
• evidence of scouring or deposition,
• estimate of type and amount of bank vegetative cover, and
• average percent of bank erosion occurring along the stream segment.

Stream habitat is assessed in conjunction with stream water quality and stream aquatic communities to determine the stream's overall health.