Grays Harbor and Chehalis River Improvements to Navigation Environmental Studies. Wildlife Studies at Proposed Disposal Sites in Grays Harbor, Washington,
WASHINGTON STATE DEPT OF GAME ABERDEEN
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A 15-month study to inventory wildlife resources on 4 proposed terrestrial dredged material disposal sties and 1 intertidal disposal site was initiated. Major emphasis was placed on inventorying birds and mammals to assess the value of these areas to wildlife. Amphibians, reptiles, and plants received less emphasis. Seven species of amphibians and 3 species of reptiles were captured on fill sites 16, 17, and 18 during this study. The spotted frog and Dunns salamander have been reported only rarely in Grays Harbor County. Most individuals of these two groups of animals would be killed by disposal of dredge materials on these sites. At least 46 species of waterbirds use the main channel and sloughs proximal to the Cosmopolis Reach of the Chehalis River. Mallards and scaup were the most common waterfowl highest numbers were seen during winter. Areas preferred by waterfowl were river marshes and upper reaches of sloughs. Large numbers more than 200 of western grebes, gulls and diving waterfowl used the Cosmopolis Reach during all seasons. During dredging, direct impacts to waterfowl and bald eagles would be negligible most observations were 5 kms or more upstream from proposed dredging activity. Impacts i.e. decreased hunting success due to suspended particulates to diving birds would be minimized by dredging between August and October, when numbers of birds are lowest. Dredging during ebb tides would result in sediments disturbed by dredging flowing into the harbor.
- Civil Engineering