Module 3: Dredging and Environmental Considerations Copy

[vc_row][vc_column][vc_single_image image=”889″ img_size=”full”][vc_column_text]Biological considerations of dredging include suspended sediments, sedimentation, chemical release, dissolved oxygen (DO) reduction, channel blockage, and entrainment.

Equipment used to control or mitigate, impacts at the excavation site are also described. The term “impact,” as used in the environmental realm, denotes detectable changes in physical, chemical, or biological components of an ecosystem. In its simplest form, an impact refers to a biological response to some physical or chemical alteration to preexisting conditions as the result of human activities or natural events. These effects may result from suspended sediments, turbidity, direct physical impact, changes in habitat, and, in certain situations, by contaminant levels.

​Different types of dredges generate differing levels of turbidity. In this course, we are using the term “turbidity” when an optical measurement of water quality was made, and the term “total suspended sediments” (TSS) is used when a gravimetric measurement of water quality was made.

We will also use the term “sediment resuspension” when describing the mixing of sediment into the water column due to dredging activities. Though the type of dredging equipment has a major effect on the amount and concentration of sediment that is resuspended, the techniques for operating this equipment also assume importance.[/vc_column_text][/vc_column][/vc_row]