Dredging has been occurring on the Wicomico river since 1872. It began as a way to move larger boats up and down an otherwise silted-in river. This was necessary to support the growing city of Salisbury. As the boats began to evolve in order to carry more cargo, the dimensions needed to change with them.
What is dredging and why does it take place?
Dredging is a process where sediment is taken from the bottom of a waterbed and deposited elsewhere. In the case of the Wicomico, the sediment (or spoils) is deposited in a spoil site, or it can also be used to rebuild wetlands. Dredging the Wicomico is necessary for Salisbury to thrive economically. Sediment is dredged from the bed and banks in order to create a channel wide enough to support barge activity. Barges are huge boats which carry large amounts of cargo. It is cheaper to transfer supplies to Salisbury via barge than any other method, therefore dredging the Wicomico is economically efficient. Below is a picture of the 2013 US Army Corps of Enginners dredging plan for the middle Wicomico. The map includes a gray line which shows the areas that will be dredged with a statement on the dimensions necessary to support barge traffic.
The project provides for a channel 14 feet deep and 150 feet wide from the Chesapeake Bay to Salisbury, including a 100 foot wide channels with turning basins 14 feet deep in the north and south prongs, and a 60-foot wide channel 6 feet deep from deep water in the river to Webster Cove, with a T-shaped basin in the cove 100 feet wide and 400 feet long and extension of the basin 200 feet long and 100 feet wide on each side. The total project length is 37 miles. The port of Salisbury has the third highest commercial port in Maryland, consisting of petroleum products and grain. Barge traffic is crucial to maintaining adequate fuel supplies for the Delmarva Peninsula. The navigation channels are maintenance dredged on an annual basis.
Source: MPO Freight Transportation Study
Spoils management is an important factor with big dredging projects. Anytime there is dredging the excess materials need to be disposed of. Currently, there are three existing dredged spoils location sites for the Wicomico River: Sharps Point, Sims Point, and White Haven. Each of these locations are experiencing capacity issues and if more space is not found the toll will be felt economically. <-- Research is being done on other methods for soil management such as converting the spoils into top soil. For more information click Table 4 on the left.
How does this affect the ecosystem?
Dredging has numerous affects on the ecosystem of a river, which can lead to losses in biodiversity, and can lead to decreased populations in fish species. Annual dredging leads to continuously suspended sediment, which as stated earlier is unhealthy for the growth of aquatic vegetation. The disturbance also has negative effects on the spawning and growth of some fish species. The process loosens sediment on the bed of the river and increases the turbidity and stress on aquatic life. Species living within the soil's habitats can be disrupted or destroyed. Also see: Hot Topics
A barge makes its way through the Wicomico (source: Google maps)