[d]redged or fill material should not be discharged into the aquatic ecosystem, unless it can be demonstrated that such a discharge will not have an unacceptable adverse impact either individually or in combination with know and/or probable impacts of other activities affecting the ecosystem of concern.

40 C.F.R. § 230.1(c) (1993).

Figure 4. U.S. Army Corps of Engineers 404 Guidelines dealing with discharge into the water.