Site Selection under MPRSA

Framework for Dredged Material Management

May 2004

4.1.1 Site Selection under MPRSA

The intent of the criteria for site selection is to avoid unacceptable, adverse

impacts on biota and other amenities. This requires that sufficient information be

assembled such that reasonable assurance can be given that the criteria will be met. As a

rule, the majority of amenities, such as fishing, shipping, mineral extraction, spawning,

breeding, nursery grounds, and cultural or historical features, may be addressed with

existing information. If so, primary concern is then directed to biological resources in and

adjacent to the proposed disposal site. These concerns are addressed by ensuring that any

geographically limited or especially significant living resources are not present within the

site nor outside the site in such a location as to be adversely impacted by movement of

material off the site if it is a dispersive site (USACE/USEPA 1984). Resources within the

site may suffer physical impacts from the deposition of the dredged material, and sites

should be designated/selected to ensure such impacts are acceptable.

The criteria provide that ocean dumping sites will be designated beyond the edge

of the continental shelf, wherever feasible, and at other sites that have been historically

used unless monitoring data or other information indicate the potential for significant

adverse impacts.

If little is known concerning the resources or the characteristics of the site and its

environs, appropriate investigations and studies must be performed. The USACE has

prepared an ocean-site designation manual (Pequegnat, Gallaway, and Wright 1990),

which provides useful guidance and procedures for conducting the appropriate

investigations and studies. In addition, overview manuals for site designation have been

developed (USACE/USEPA 1984; USEPA 1986). Procedures for application of risk

assessment to the aquatic environment can be found in Cura et al. (2001).

4.1.2 Site Specification under CWA

The specification of disposal sites under the CWA is addressed specifically in the

Section 404 (b)(1) Guidelines. The Guidelines establish a sequential review of a proposed

project, the first step of which is avoidance of adverse impacts to the aquatic environment

through an evaluation of practicable alternatives which would have less impact on that

environment [40 CFR 230.10 (a)]. In general, the same concerns as given above for

ocean-site designation are applied to site specification under CWA. These include

potential impacts on physical and chemical characteristics of the aquatic ecosystem,

potential impacts on biological characteristics of the aquatic ecosystem, potential effects

on special aquatic sites, and potential effects on human-use characteristics (40 CFR 230

Subpart C-F).

The specification of an appropriate site under CWA takes into account that CWA

disposal sites may be located in estuaries, rivers, and lakes that may have limited

assimilative capacity. Geographic and operational constraints as well as site capacity may

severely constrain potentially available sites.