Dredging in White Creek and part of the Assawoman Canal is set to begin in early 2023. Both waterways are important navigation channels in the Inland Bays.
White Creek is northwest of Bethany Beach. It flows from the south to the north into Indian River Bay. It serves numerous marinas and boat ramps and connects Assawoman Canal to the bay.
The White Creek navigation channel was last dredged as part of a phased program from 1997 through 2001. The Assawoman Canal was most recently dredged from 2010 to 2015.
Since then, navigability within both channels has decreased due to sedimentation and shoaling.
The Department announced on Dec. 13, 2022 that dredging would begin in January of 2023. The $4.685 million project will be undertaken by DNREC’s Shoreline and Waterway Management Section and the contractor ResilientSeas, LLC.
The project is project is funded largely from appropriations to DNREC in the fiscal year 2022 and FY23 budgets.
DNREC’s data-based method to prioritize dredging projects identified White Creek as a top priority. This method includes surveys of residents and users of the waterway. And it considers analysis of channel depth, boater safety and environmental considerations.
The project will improve navigability in White Creek and a portion of Assawoman Canal. It will restore an area of highly degraded coastal salt marsh using dredged material. It will help coastal wetlands adapt to sea level rise and other environmental stressors.
The project will remove approximately 55- to 70-thousand cubic yards of shoaled sediments. This will bring the White Creek navigation channel and Assawoman Canal to previous dredge design depths.
DNREC will make beneficial use of the dredged material to restore wetlands in the Muddy Neck Marsh Complex, which is close to the dredging area. This will restore historically degraded wetlands. And it will improve the resilience of the marsh in future coastal storms.
The project will use thin layer placement of dredged materials. This minimizes marsh disturbance and restores the marsh through natural recolonization of vegetation.
DNREC engaged engineering services from Anchor QEA + Woods Hole Group Joint Venture to design the dredge project and oversee its construction.
For White Creek, an area 60 feet wide and 12,400 feet long will be dredged — from the mouth of the creek, at Indian River Bay, to where the main channel splits into two prongs near Betts Avenue, in Ocean View.
For the Western Prong, an area 35 feet wide and 4,100 feet long will be dredged. Per the issued permits, dredging in the Western Prong will end at coordinates 38.550020, -75.106274 — almost to Old Mill Road and near 125 Naomi Drive.
For the Eastern Prong, an area 35 feet wide by 2,150 feet long will be dredged. Per the issued permits, dredging in the Eastern Prong will end at coordinates 38.54827300, -75.09963000 — approximately between 4 White Creek’s Lane and 6 Cristy Lane.
For the Assawoman Canal, an area 35 feet wide and 2,400 feet long will be dredged, between its confluence with White Creek and the Central Avenue bridge.
The White Creek channel will be restored to a depth of 4 feet below mean lower low water (MLLW). The northern Assawoman Canal will be restored to a depth of 3 feet below MLLW.
|White Creek – Main Channel||11,700||60||-4||29,000|
|White Creek – Eastern Prong||2,600||35||-4||17,000|
|White Creek – Western Prong||3,700||35||-4||22,000|
|Note: The depths do not include an allowed “overdredge” of up to one foot. The quantity totals do.|
The project will provide multiple benefits, including:
The Muddy Neck Marsh Complex is part of the Assawoman Wildlife Area. It is an expansive coastal salt marsh system located west of the southern end of Assawoman Canal. It stretches up to a half mile from the adjacent upland shoreline.
The site is a fragmented tidal wetland complex with several open water pool areas. Plant life in the area includes smooth cordgrass, salt hay cordgrass, spike grass, common reed, glassworts, sea lavender, marsh elder, groundsel bush, salt marsh bulrush and switchgrass.
The Assawoman Wildlife Area supports a variety of fish species, including Atlantic silverside, mummichog, spot, striped killifish, summer flounder and sheepshead minnow.
Restoration of the Muddy Neck Marsh Complex will provide improved habitat value to one of Delaware’s critical natural areas. This area has been subject to ongoing threats of climate change, sea level rise and marsh platform loss.
The Muddy Neck Marsh Complex has experienced widespread ponding and fragmentation over the last 60 to 70 years. Between 2007 and 2017 alone, approximately 11 acres within the Complex changed from vegetated area to open pond. Of the122 acres proposed for marsh restoration, about 70 acres are unvegetated.
The project will place restoration material on the marsh using thin layer pressure spray nozzles. Materials will be spread over three areas (Beneficial Use Cells) in thicknesses ranging from a half foot to one foot.
The dredged material will be mostly mud (silt and clay) and some sand. This material is not suitable to place on local beaches (as in the 2020 Masseys Ditch Dredging Project). But this material is ideal for restoring degraded local marshes.
Restoring degraded marshes using dredged material is a common practice nationwide. It and has been done in Delaware. In 2013, DNREC’s Shoreline and Waterway Management Section and Wetlands Monitoring and Assessment Program joined to for a successful marsh restoration at the Piney Point Tract of Assawoman Wildlife Area. That project used a thin layer of material dredged from Pepper Creek.
Numerous projects in southern New Jersey have used dredged material to restore marshes.
On July 28, 2021, DNREC hosted a virtual public information session, attended by approximately 125 people, to share information and solicit questions and feedback about the project.
The public information session included a presentation on the project and has led to development of a set of questions and answers about the project.
A second public project information session was held on Jan. 19, 2022.
Currently, this project is in the construction phase.
Removal of derelict crab pots and other marine debris from the project area is complete.
Mobilization of the dredge and placement of the pipeline is complete. Dredging in the Assawoman Canal is expected to start in late February.
Permit conditions require the dredging project to be completed by the end of March to minimize impacts to hibernating terrapins.
The project area will be monitored by DNREC through 2028.
For more information, please contact Joanna French at 302-739-9921.
Related Topics: assawoman canal, boating, channel, dredge, dredging, inland bays, watershed stewardship, waterways, white creek