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Aquatic Habitat

In the MFWW, aquatic habitat primarily refers to wetlands, streams, springs, ponds, rivers and lakes.

Aquatic habitats are home to countless fish, macroinvertebrates, and amphibian species, including:

bull trout in the Middle Fork of the Willamette

Fish species:

char, trout, whitefish, large scale suckers, squawfish, redsided shiners, cutthroat trout, rainbow trout, brook trout, mountain whitefish, two known sculpin species (torrent and Paiute), large-scale sucker, speckled dace, Northern squawfish, Brook lamprey and
Endangered - spring Chinook salmon, Oregon chub, and bull trout

Amphibian species (all listed as sensitive):

red-legged frog, cascade frog, tailed frog, Oregon slender salamander, western toad, and northwestern pond turtle

Distribution of Aquatic Habitat

The MFWW contains over 1000 miles of streams and rivers; off-channel habitats such as oxbows, floodplain ponds, and wetlands; lakes such as the pristine Waldo Lake, as well as countless other high elevation lakes; and several flood-control reservoirs - Lookout Point, Fall Creek, and Hills Creek.

Threats to Aquatic Environments in the MFWW

Habitat: Altered hydrologic processes, changes in water temperature regimes, modified riparian and aquatic habitat, and limited access to historic spawning and rearing areas have reduced available high quality habitat and impacted population productivity, capacity, and diversity for Chinook salmon, bull and cutthroat trout. Upper and lower reaches of the river have been impacted by installation of riprap to protect roads, gravel mining, and channel engineering. Furthermore, past management practices in riparian areas and stream cleaning practices have led to reduced large wood loads in the aquatic system. Reduced in-channel wood has modified gravel deposition patterns, reduced the frequency and depth of pools, and minimized hiding cover for adult and juvenile fish.

Fish passage: Dams have greatly reduced peak flow events that are essential to creating and maintaining habitat complexity, including spawning gravels, deep pools, and side channels. Dams block the interchange between the upper and lower watershed Chinook and trout populations and limit juvenile access into rearing and refuge habitat.  Along with dams, fish passage barriers at road crossings prevent access into historical spring Chinook salmon, bull and cutthroat trout spawning areas.

Water quality: The overall water quality of the MFWR is considered some of the highest of the entire Willamette River Basin; however, comprehensive sampling of water quality parameters has not been conducted throughout the basin. Temperature is the greatest water quality concern in the MFWW. The alteration of riparian areas has reduced riparian shading along tributaries of the lower watershed and, to a smaller degree, of the upper watershed.  Along the mainstem MFWR, release of water from the dams reverses natural seasonal trends by decreasing water temperatures in late summer and increasing them in the fall and winter, which impacts the upstream of distribution of spring Chinook salmon adults, alters the timing of spawning, and affects the survival of eggs.

Council Goals for Aquatic Habitat:

MFWWC Projects involving aquatic habitat:

Informational Links

Distribution of fish in the MFWW
Distribution of culverts in the MFWW