The offshore borrow area is located between the first and second 

 reefs (Figs. 1 and 2). During August and September 1972, approxi- 

 mately 274,016 cubic meters of sand was dredged and pumped from this 

 area onto Hillsboro Beach, leaving two elongated pits in the ocean 

 floor (Fig. 2) . The northernmost pit is the sampling area evaluated 

 in this study. 



The borrow area, still well-defined 8 years after its excavation, 

 is approximately 200 meters long and 70 to 75 meters wide. The inshore 

 edge slopes from a depth of 10.0 meters outside the pit to a depth 

 ranging from 13.5 to 15.0 meters inside. The outer edge of the trough 

 is steeper than the shoreward edge, sloping up at a 30° to 40° angle to 

 the undisturbed sea floor. Along the edge of the slopes is an area of 

 rubble, left from the dredging operation, that is inhabited by many 

 reef fishes and invertebrates. The sandy bottom of the borrow area is 

 generally flat, except for a few scattered sunken tires broken away 

 from a nearby artificial reef. 



Water currents in this area are predominantly southerly, although 

 there is considerable variability in both direction and velocity. 



III. SAMPLING AND ANALYTICAL PROCEDURES 



Sediment Analysis. 



During the initial sampling period, three replicate core samples 

 from each station were obtained for sediment analysis. An aliquot of 

 each was dispersed for 24 hours in a 4-percent solution of sodium 

 hexametaphosphate (Calgon), and then washed through a 0.063-millimeter 

 sieve to separate the silts and clays from the sand. The sand was 

 ovendried at 90° Celsius for 12 hours, then fractionated according to 

 the Wentworth scale. Each fraction was weighed to the nearest 0.01 

 gram. Organic content was determined by ovendrying an additional 

 sediment aliquot, then measuring the percent weight loss after incin- 

 eration at 500° Celsius for 1 hour. 



Significance testing of grain-size differences was conducted usin^ 

 an analysis of variance. 



2. Faunal Analysis . 



Seasonal samples of benthic fauna were collected from four 

 sampling stations — two control stations (1 and 2), representing the 

 comparatively undisturbed bottom and two borrow stations (3 and 4). 

 Control stations 1 and 2 were located 300 and 200 meters, respectively, 

 north of the borrow area (Fig. 2). Borrow stations 3 and 4 were 

 located 90 meters apart within the borrow area. 



