Mound crest

mounds created have had reasonably consistent geometries. Most mounds

have been round or elliptical in shape, with a defined crest that is relatively

flat, a main mound side slope (also termed the inner flank), sometimes an

outer flank, and a thin outer apron. Figure 16 shows a generic contaminated

mound. The dimensions for the side slopes and apron widths are based on

those seen at the Port Newark/Elizabeth mound created in the Mud Dump

site in 1993. The following paragraphs describe each of the mound fea-

tures in more detail.

Figure 16.

Typical mound geometry

Mound crest

Most contaminated mounds to date have had main mound crest eleva-

tions of 1 to 2 m, though some contaminated mounds with elevations of

3+ m have been constructed. Higher mounds have been constructed from

noncontaminated material. For point-dumped projects in the New Eng-

land Division, mound crests have generally been circles or ellipses ap-

proximately 100 to 200 m in diameter, reflecting good control of the

disposal process around a taut-moored buoy (disposal within about 25 m

of the buoy), for moderate-sized projects, generally 20,000 to 100,000 yd3.

The 1993 Port Newark/Elizabeth project used disposal lanes, 150 m in

width and 300 to 420 m long, to create a triangular-shaped mound, ap-

proximately 630 by 645 m, with peak elevations of 1.5 to 2.4 m.

Chapter 6 Sediment Dispersion and Mound Development and Site Geometry During Placement