channel. Sediment was pumped as water slurry via a pipeline across the island 
to the beach. Figure 5 is a map showing the nourished area and the pipeline 
route. The sediment-water slurry was released alternately from one of two dif- 
fuser heads branching from the end of the pipeline. Figure 6 shows the sedi- 
ments coming from the diffuser head. 
The material deposited by the pipeline consisted of harbor sediments. These 
sediments were generally gray to black, indicating that they came from a reduc- 
ing environment. Park rangers reported at times the smell of hydrogen sulfide 
(a product of anaerobic respiration). 
A series of corings of the harbor sediments were obtained before nourish- 
ment by Alpine Geophysical Associates, under contract to the U.S. Army Engineer 
District, Wilmington (U.S. Army Engineer District, Wilmington, 1976). An 
analysis of these cores revealed that the average grain size of the sediments 
was slightly larger than that of Fort Macon beach. However, a much larger 
proportion of fossil shells and fossil shell hash was present in the nourish- 
ment material than was originally present on the Fort Macon beach. Coarser 
material was quickly sorted out of the intertidal zone and deposited farther up 
on the beach by tidal action. Concentration of coarse materials on Fort Macon 
beach is shown in Figure 7. 
At times a high proportion of the materials being deposited came from clay 
lenses. This material was formed into large numbers of clay balls by the action 
of the pipeline. These clay balls remained on the beach until they were worn 
down either by drying and fracturing or abrasion in the surf zone (Fig. 8). 
Nourishment extended the original width of the beach an average of about 
75 meters. This caused the beach slope in the intertidal zone to increase 
from 3 to 5 percent. Following nourishment the eastern half of the beach 
exhibited a 0.2- to 1.5-meter-high scarp located where the highest high tide 
since nourishment had scoured. This scarp moved and changed shape and size 
daily in some places but remained a persistent feature of the beach for several 
months following nourishment. 
IV. METHODS 
1. Fieldwork. 
The beach at Fort Macon was monitored from January 1977 to September 1978. 
Quantitative biological samples were collected twice monthly from the inter- 
tidal zone at Fort Macon between June 1977 and September 1978. Quantitative 
biological samples from the intertidal zone of the comparison beach at Emerald 
Isle were taken twice monthly between September 1977 and September 1978. Sam- 
ple collecting was timed to coincide as nearly as possible with low tide. 
a. Physical Measurements. Water and air temperatures were measured at 
each beach using a centigrade glass mercury thermometer whenever samples were 
collected. Temperatures were recorded to the nearest 0.5° Celsius. At the 
same time, windspeed was measured using a Simms Electronic Anemometer (model 
number BT), and salinity was measured using an American Optical Goldberg refrac- 
tometer. Wind direction and wave height of the surf were estimated. On two 
occasions beach slope was measured in the intertidal zone using a tape measure, 
meter stick, and carpenter's level. Several replicate profiles at different 
locations on each beach were measured on each of these occasions. 
15 
