nutrient cycling research which will be 

 discussed under the marsh development 

 task. See Figure 1 . 



A typical example of research being 

 conducted in this task area is a study 

 at St. Simons Island in Georgia, to de- 

 termine the effects of smothering on 

 marsh grasses. In this study, Spartina 

 alterniflora , the dominant salt marsh 

 grass, is being subjected to disposal of 

 sand, silt, and clay dredged material at 

 controlled depths from 7.6 cm (3 inches) 

 to 1 m (3.3 ft). The experiment will be 

 repeated during the dormant, growing, 

 and reproductive seasons to interpret 

 seasonal impacts. The impact of these 

 disposal applications will be determined 

 by changes in marsh productivity and 

 succession. 



The development task is the princi- 

 pal thrust of the Habitat Development 

 Project. We have, or have attempted, 

 field studies at Branford, Connecticut; 

 in the James River, Virginia; in the Po- 

 tomac River near Washington, D.C.; on 

 the coast on the Bolivar Peninsula, 

 Texas; in San Francisco Bay; at Miller 

 Sands in the Columbia River; and at 

 Grays Harbor, Washington. 



The field site at Branford, Con- 

 necticut, was terminated last October. 

 We had intended to develop a 3.2-ha 

 (8-acre) marsh as an extension of the 

 existing marsh, thereby disposing of 

 30,600 m 3 (40,000 yd 3 ) of fine-grained, 

 contaminated dredged material. From its 

 conception, this project met with sub- 

 stantial local opposition, and, despite 

 numerous safeguards and assurances, we 

 were never able to gain community ap- 

 proval. The most common concern voiced 

 by opponents was that the newly created 

 marsh might, because of its experimental 

 nature, threaten real estate values in 

 the area. Other concerns were odor, dan- 

 ger to neighborhood children, and mos- 

 quitoes. Repeated delays finally placed 

 the project in an untenable time frame 

 which resulted in its cancellation. 



A 5.6-ha (14-acre) marsh develop- 

 ment site in the James River, Virginia, 

 was built last year by taking 53,550 cm 3 

 (3,207 inches 3 ) of contaminated fine- 

 grained dredged material from the navi- 

 gation channel and confining it behind a 

 hydraulically placed sand dike. We had 

 intended experimental planting on this 

 site, but Mother Nature was more effi- 

 cient, and by July of the first growing 



season, the area had naturally vege- 

 tated. Fortunately, a desirable mix of 

 wetland species developed including 

 arrow arum ( Peltandra virginica ), pick- 

 erel weed ( Pontederia cordata ), and 

 arrowhead ( Sagittaria spp. ). The main 

 thrusts of research at the James River 

 site now involve the potential uptake of 

 contaminants by plants growing on the 

 dredged material and documentation of 

 the biological productivity of the site. 

 These studies should result in important 

 findings regarding the environmental im- 

 pact and feasibility of marsh develop- 

 ment as a disposal alternative. 



We have a potential marsh develop- 

 ment site quite close to Washington, 

 D.C. at Dyke Marsh on the Potamac just 

 south of Alexandria. This area was 

 extensively mined for gravel in the 

 1930's, and during these mining opera- 

 tions a considerable portion of Dyke 

 Marsh was destroyed. Ownership of the 

 area has since passed to the Government, 

 and the National Park Service has a Con- 

 gressional mandate to restore Dyke Marsh 

 to its original configuration. We have 

 entered into a cooperative study with 

 the Park Service, the Corps' Baltimore 

 District and the Fish and Wildlife Ser- 

 vice to evaluate the feasibility of us- 

 ing dredged material from the Potomac 

 River as a substrate for marsh estab- 

 lishment at this site. 



The marsh will be restored by plac- 

 ing approximately 229,500 m 3 (300,000 

 yd3)of dredged material, covering 11.3 

 ha (28 acres) at an intertidal elevation 

 behind a sand dike. The feasibility 

 phase of this study will be completed 

 May 1976. If the project proves feasi- 

 ble, and agency and public support is 

 obtained, we will proceed to the de- 

 tailed design phase. If this project is 

 completed, approximately 10% of Dyke 

 Marsh will be restored to near-original 

 conditions. 



A former dredged material island at 

 Buttermilk Sound on the Georgia coast 

 was selected for study. We have estab- 

 lished a 1.2-ha (3-acre) salt marsh at 

 this site by shaping a mound of dredged 

 material so that approximately half was 

 intertidal. More than 800 plots have 

 been established at this site to test 

 the survival and productivity of eight 

 plant species at three tidal elevations, 

 under four fertilizer regimes. This 

 project is also designed to obtain data 



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