pink salmon fry within the marina in 

 large concentrations. 



Shilshole Marina is designed with a 

 detached rubble mound breakwater. 

 This allows for openings at both ends 

 of the marina, as well as good tidal ex- 

 change and surface water movement. 

 This design also facilitates easy passage 

 for salmon. 



Washington State Department of 

 Fisheries (1971) recommends the use of 

 open structures, as opposed to solid 

 fill, to minimize impact on fish and 

 shellfish in this region. Where solid 

 structures are used, breaches should 

 be provided to allow salmon fry passage 

 without going into water greater than 

 12 in (30 cm) deep at all tidal levels. 

 Shilshole and Kingston Marinas are more 

 conducive to salmon fry migration be- 

 cause they do not restrict passage to 

 the extent of Edmonds and Des Moines 

 Marinas. Shilshole Kingston Marina has 

 a particularly favorable design with the 

 detached breakwater allowing salmon 

 passage at both ends of the marina. 



Edmonds Marina and Des Moines 

 Marina are examples of marinas with 

 "restrictive breakwaters" (Heiser and 

 Finn 1970). They inhibit water circula- 

 tion under normal circumstances and 

 could result in rather serious effects if 

 a spillage of toxic materials occurred. 

 Marinas such as Kingston and Shilshole 

 allow for more rapid dilution which can 

 reduce such hazards (Heiser and Finn 

 1970). Edmonds Marina has an added 

 disadvantage in that it is located close 

 to a sewage outfall. Stockley (1974) 

 recommends that marinas not be located 

 closer than one-half mile to primary 

 sewage plant or industrial waste out- 

 falls. 



CASE HISTORY - JETTY IN COASTAL 

 REGION 1 - NORTH PACIFIC 



Tillamook Bay, located about 50 mi 

 (80 km) south of the mouth of the Co- 

 lumbia River, is Oregon's second larg- 

 est estuary. It is about 6 mi (10 km) 

 long and varies in width to a maximum 

 of 3 mi (5 km). Over half the area of 

 the estuary can be considered tidelands 

 (U.S. Army Engineer District, Portland 



1975b). Tides are diurnally unequal 

 with a range of about 7.5 ft (2 m) in 

 the bay (Terich and Komar 1973). Bay- 

 ocean peninsula, a narrow sand spit 

 about 4 mi (6 km) long, extends from 

 the channel entrance at the north end 

 of the bay south to Cape Meares, a 

 rocky headland (U.S. Army Engineer 

 District, Portland 1975b). Longshore 

 currents are southerly from May to 

 November and northerly from January 

 through April. Net littoral transport is 

 thought to be near zero. The tidal cur- 

 rents at the inlet are strongly influenc- 

 ed by the geometry of the inlet and bay 

 (Terich and Komar 1973). 



No prejetty data exist for environ- 

 mental conditions at Tillamook Bay. The 

 U.S. Army Engineer District of Portland 

 (1975b) described the present setting in 

 its environmental impact statement on 

 dredging and jetty maintenance. Water 

 quality is moderate to high; local tur- 

 bidity is sometimes caused by high run- 

 off conditions in incoming rivers. No 

 complete inventories of fish and wildlife 

 resources of the area exist, although 

 considerable data are available. Both 

 salt and freshwater fishes are present 

 and the bay is a migration route for 

 anadromous fish. Herring and other 

 fishes spawn in the estuary. Dungeness 

 crabs, oysters, clams, and shrimp are 

 abundant, providing major recreational 

 activities. Eelgrass beds are found in 

 several areas of the estuary. 



The history of the two jetties at 

 the mouth of Tillamook Bay, Oregon 

 (Figure 54), is amply documented. 

 Early diaries, photographs, newspaper 

 articles, and government documents 

 describe the area before jetty construc- 

 tion, following construction of the north 

 jetty and after construction of the 

 south jetty. Unfortunately, these sources 

 of information neglect to depict the 

 original biology or to describe biological 

 changes which have occurred over the 

 years. History of physical changes in- 

 fluenced by the jetties is easily found, 

 but changes in the biota must be infer- 

 red. 



A journal of an early explorer, 

 written in 1788, describes Tillamook Bay 

 (Terich and Komar 1973). The entrance 



109 



