It is an amazing fact that during flooding and high-water events, the upper Rappahannock River can carry sediment loads exceeding several thousand cubic yards of silt. In the words of Kathleen Harrigan, former executive director of the Friends of the Rappahannock, “the river is naturally a sediment transport system and if dredging is done, it would have to be on a continuing basis to be effective.”
I was an environmental scientist with the U.S. Army Corps of Engineers in the Fredericksburg Field Office for 24 years. Over these decades, I have witnessed the annual high-water events on the Rappahannock River in Fredericksburg and the accompanying public opinions played out in The Free Lance–Star regarding the shoaling below the Fall Line. One article references a paddlewheel riverboat below the Fall Line in Fredericksburg getting stuck on a sandbar in the river and includes a quote from John Tippett, former director of the Friends of the Rappahannock, regarding the actual cause of the shoaling. He states: “The sediment in the river comes from two primary sources: plowed farm fields and eroding streambanks.” There are several other news articles from the 1990s referencing the large volumes of sediment that appear each year in the lower Rappahannock River associated with high water events. Most of these articles were published prior to the breach of the Embrey and Crib dams in 2004.
In the late 1990s, going into the early 2000s, I was a member of the project delivery team (PDT) with the Corps. The Corps, in partnership with the city of Fredericksburg and the Virginia Department of Game and Inland Fisheries, was authorized by Congress with the task of breaching and removal of the Embrey Dam and the Crib Dam behind it. Prior to the breach of the Embrey and Crib dams in February 2004, the PDT identified a location for a dredge containment facility in the upland and it was constructed. Some 250,000 cubic yards of silt was then dredged from behind the two dams and deposited in this upland containment facility. After the breach of the dams, some silt remaining from behind the dams did migrate downstream, prompting the Corps to return and dredge an additional 20,000 cubic yards of silt remaining from behind the two dams.
It has now been over 18 years since the removal of the Embrey and Crib dams. In my opinion, one of the most effective ways to address the current silting and sediment shoaling in the lower Rappahannock River is through the planting of streamside forest buffers in the upper watershed of the river. Environmental conservation groups such as the Friends of the Rappahannock have been greatly involved in this activity. Dredging the river to remove the sediment may only provide short-term benefits and can be harmful to aquatic life, not to mention the costs and expense of building containment facilities in the upland, along with permitting by state and federal agencies to accomplish this.
Hal Wiggins, a retired environmental scientist and naturalist, is a resident of the Fredericksburg area.
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