Carbaryl, Carbofuran, and Methomyl - National Marine Fisheries ...

Whitney 1979). Similarly, over one third ( 2,000 km) of coho salmon habitat is no longer
accessible (Good, Waples et al. 2005). The mainstem habitats of the lower Columbia and
Willamette rivers have been reduced primarily to a single channel. As a result, floodplain
area is reduced, off-channel habitat features have been eliminated or disconnected from
the main channel, and the amount of LWD in the mainstem has been reduced.
Remaining areas are affected by flow fluctuations associated with reservoir management
for power generation, flood control, and irrigation. Overbank flow events, important to
habitat diversity, have become rare as a result of controlling peak flows and associated
revetments. Portions of the basin are also subject to impacts from cattle grazing and
irrigation withdrawals. Consequently, estuary dynamics have changed substantially.
Stream habitat degradation in Columbia Central Plateau is relatively high (Williamson,
Munn et al. 1998). In the most recent NAWQA survey, a total of 16 sites were evaluated
- all of which showed signs of degradation (Williamson, Munn et al. 1998). Streams in
this area have an average of 20% canopy cover and 70% bank erosion. These factors
have severely affected the quality of habitat available to salmonids. The Palouse subunit
of the Lower Snake River exceeds temperature levels for the protection of aquatic life
(Williamson, Munn et al. 1998).
Habitat loss has fragmented habitat and human density increase has created additional
loads of pollutants and contaminants within the Columbia River Estuary (Anderson,
Dugger et al. 2007). About 77% of swamps, 57% of marshes, and over 20% of tree cover
have been lost to development and industry. Twenty four threatened and endangered
species occur in the estuary, some of which are recovering and others (i.e., Chinook
salmon) are not.
The Willamette Basin Valley has been dramatically changed by modern settlement. The
complexity of the mainstem river and extent of riparian forest have both been reduced by
80% (PNERC 2002). About 75% of what was formerly prairie and 60% of what was
wetland has been converted to agricultural purposes. These actions, combined with urban
development, extensive (96 miles) bank stabilization, and in-river and near-shore gravel
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