able 3. Monitoring of Beachsaver Reef at Avalon, New Jersey.

Figure 12. Average settlement after 33 months for the first 57 units and after 20 months for the remaining 273 units at the P.E.P. Reef installation at Midtown Palm Beach (after Dean and Chen, 1996).

Sediment Volume Response - coas_19_202_684_7220014

coas_19_202_684_722
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13

696

Stauble and Tabar

Table 3. Monitoring of Beachsaver Reef at Avalon, New Jersey.

Events/Other Monitoring

Beachsaver Installation

June

Beach Fill #5

July

Survey

September

Survey

December

Survey

with large movements of the ebb shoal sand bodies in the

in 1978 used the inlet ebb shoal as a borrow source. The ebb

vicinity of the north end of Avalon (FARREL, 1995). The top

channel at Townsends Inlet was realigned from its natural

of the reef structure was placed between 0.4 and 2.0 m

southward trending orientation to a channel that cut straight

( 1.3 and 6.6 ft) MLW in a water depth of 2.2 to 3.8 m (7.2

across the middle of the ebb shoal. The Sea Isle City beach

was renourished in 1984 using the same ebb shoal borrow

to 12.5 ft) MLW. A geotextile fabric was placed under the

area. As this channel realigned, the north end of Avalon's

Beachaver units for scour protection. Halfway through the

shoreline eroded (FARREL, 1995). Due to this severe loss of

monitoring period a polyethylene geomattress filled with

beach sand, four beach nourishment projects were completed

stone was placed along the southern 73 m (240 ft) of the land-

on the north end of Avalon, starting in 1987, with 997,803 cu

ward side of the base to mitigate for scour (BRUNO et al.,

m (1.305 million cu yd) of fill placed between 8th and 28th

1996a). Additional structures in the study area include a tim-

Streets. In 1990, an additional 308,898 cu m (404,000 cu yd)

ber bulkhead that runs parallel with the beach and delin-

of fill was placed from 9th to 16th Streets and from 21st to

eates the landward extent of the sand beach. A pile-supported

27th Streets. By 1992, an additional 313,486 cu m (410,000

storm water outfall pipe is located to the south at 11th Street

cu yd) of fill was placed between 9th and 16th Streets. Fi-

and extends approximately 61 m (250 ft) seaward perpendic-

nally, in 1993, 182,739 cu m (239,000 cu yd) of sand was

ular to the shoreline (BRUNO et al., 1996b).

added between 8th and 15th Streets and along the inlet shore

(FARREL, 1995). Along with this last fill, geo-tubes were

Monitoring Program

placed along the inlet shoreline to help retain the fill and

protect the bulkhead. The Beachsaver Reef was installed off

Project monitoring included establishment of a project

the 8th Street jetty to help hold the sand fill at the north end

baseline and 27 beach profile lines perpendicular to the shore

of the island, adjacent to the inlet. At the end of the Beach-

parallel baseline, beginning with Profile A next to the 8th

saver monitoring period in June 1995, an additional beach

Street Jetty and extending south to Profile W (Figure 13).

fill placed 305,840 cu m (400,000 cu yd) along the north end

Profiles were approximately 30.4 m (100 ft) apart and the

of the beach (BRUNO et al., 1996b). This new fill buried the

total shoreline covered was around 823 m (2,700 ft) south

submerged reef. Monitoring of the fill continued through De-

from the 8th Street jetty (BRUNO et al., 1996b). Profiles were

cember 1995.

measured with a total station and prism on land and a fa-

thometer on a boat in the offshore to a depth of 2.44 m ( 8

The 305 m (1,000 ft) long, submerged breakwater, com-

posed of 100 Beachsaver units, was attached at its north end

ft) MLW. One pre-installation survey was done in May 1993

to the terminal end of the 8th Street jetty (HERRINGTON and

and post-installation surveys were collected in September

BRUNO, 1998). It extends to the southwest in a more or less

1993 soon after placement, November 1993, January, March,

shore-parallel direction some 100 to 150 m (328 to 492 ft)

May, September and November 1994 and February and May

seaward of the shoreline, with its south end open to the

1995 (Table 3). The two 1995 surveys were limited to the area

ocean. The installation was done from barges in the water.

landward of the reef due to a sand transfer operation after

Steel H-piles were driven into pre-cast openings in the center

sever erosion in January 1995, which included profile lines A

of the concrete reef structure at all end or transition units to

through G (BRUNO et al., 1996a). Settlement measurements

provide more stability (BRUNO et al., 1996b). This site was

were initially estimated from visual observations. High rates

strongly influenced by tidal currents and the ebb shoal fea-

of settlement resulted in surveys of the top elevation of the

tures of Townsends Inlet. The inlet has been highly dynamic,

reef starting in November 1993 and extending to May 1995

Journal of Coastal Research, Vol. 19, No. 3, 2003

Index

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