ISLES OF SHOALS 



The actual location of the Isles of Shoals disposal site that could be used 

 as a regional dumping ground has not been officially designated. A large 

 dumping ground (Fig. C-l ) between 1 and 3 miles east of the Isles of Shoals 

 has been used in the Dast for a small amount of dredge spoil from the Portsmouth - 

 Kittery area. The bottom is largely rocky but is penetrated by several valleys 

 containing soft sediment. Previous dumping was not specific to areas within the 

 site and the location of spoil is not known. No effects of spoil have been re- 

 ported, however, there are many metal racks on the seafloor which have been jeti- 

 soned from aircraft using jet assisted takeoff (JATO) from Pease Air Force Base. 



Selection of a disposal point within this historical site has been under- 

 taken by the DAMOS program to provide baseline data should dredging in the 

 Piscataqua River be required in the future. The actual space needed for "point 

 dumping" of spoil is probably h x h mile but a 1 x 1 mile site will be estab- 

 lished. The site chosen for study of currents and fisheries is a valley on the 

 east side of the large dumping ground. 



Sathymetry 



Navigation for surveys in the Isle of Shoals area was provided by trisponder 

 stations at a surveyed site in York, Maine and at Newburyport Light. Side scan 

 and subbottom data indicate that the disposal area is composed of outcrops of 

 basement rock, arvd flat areas covered by a soft acoustically transparent mud. 



The first bathymetric survey of the site in December, 1977 (Fig. C-2(a-g)) 

 indicated a flat, soft area would be present on the eastern edge of the disposal 



