Profiles

changes, wave and current assessment and aerial photography

Profiles

The groin cells are indicated in Figure 2, and are numbered "1" through "8" from

southeast to northwest. Groin cells 1, 2, and 3 are 152 to 168 m in width, as measured

between the seaward ends of the structures. The remaining groin cells (4 through 8) are

between 213 and 244 m wide. Three cross-sections were established and surveyed in

groin cells 1, 2, and 3, with four cross-sections established and surveyed in cells 4

through 8. A total of 29 cross-sections were surveyed in the eight groin cells. In each

cell, profiles were measured at a distance of 30.5 m feet from the groins that define each

cell. In groin cells 1, 2, and 3, one additional profile line was surveyed midway between

the two "outer" lines. In groin cells 4 through 8, two additional cross-sections were

surveyed at approximately equal intervals between the outer lines, normal to the shoreline

alignment at the survey control point.

Profiles were established at a project-specific set of semi-permanent benchmarks

(concrete post or metal pipe with survey disc). The surveys were collected relative to NJ

State Plane Grid Coordinates (NAD83) with a vertical datum of NAVD88. Each cross-

section extended from behind the dune line seaward from the survey monument for a

distance of 152 m (short line surveys for pre-construction data) or 1250 m (long line

surveys for area wide coverage) beyond the seaward ends of the groin cells. In cells with

a sill or submerged breakwater (cells 2, 3, 5, and 6), elevations at the landward toe, crest,

and seaward toe of the sill or breakwater unit was measured where the profile line

crossed the structure. The profiles over the dune were measured with a GPS survey

system and the beach and foreshore out to wading depth were measured with either the

GPS system or survey/rod method. A boat/fathometer survey continued the line seaward

to the survey limit to measure the nearshore inside the cells as well as the marginal flood

channel and shoals found in the nearshore.

The initial detailed bathymetric survey of cells 5 and 6 were collected in January

2002 and the 29-line survey of the entire Cape May Point beach area was collected in

March of 2002 to characterize the pre-construction bathymetry. An additional detailed

survey was collected in June 2002 in cells 5 and 6 prior to construction of the new

structures to determine placement options and locations. Earlier profiles were collected

in July 2000 and January 2001 of selected sites within the study area. The bathymetry

shows that a flood channel is located just off the groins and a dynamic and changeable

shoal is located seaward of that (Figure 7).

The monitoring of the beach profile evolution will measure shoreline change and

bathymetric grids constructed in the Geographic Information System (GIS) will measure

sediment volume change, which is an indicator of how much sediment is retained behind