Posted on December 6, 2023
Preparation work for a dredging project in White Creek and the Assawoman Canal is set to begin before the start of 2024. 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 the 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.
Dredging Project Awarded
The Department of Natural Resources and Environmental Control (DNREC) awarded the project to dredge White Creek and the Assawoman Canal to McLean Contracting Company on Oct. 27, 2023. The $8.483 million project will begin in December of 2023. The portion of White Creek that was not completed during a previous project at the beginning of 2023 will be dredged prior to Assawoman Canal.
The project is funded largely from appropriations to DNREC in the fiscal year 2022 and FY23 budgets.
Project Overview
DNREC’s data-based method to prioritize dredging projects identified White Creek and the Assawoman Canal as top priorities. 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 the 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 80 thousand cubic yards of shoaled sediments. This will bring the White Creek navigation channel and the 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.
Project Details
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 Assawoman Canal, an area 35 feet wide and 2,400 feet long had been dredged, between its confluence with White Creek and the Central Avenue bridge, earlier in 2023. The remainder of the Canal will be dredged with a channel width of 35 feet.
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.
Proposed Dredging Area and Volumes
The project will provide multiple benefits, including:
- Return of navigable depths to recreational boating channels
- Restoration of severely degraded coastal wetlands in one of Delaware’s premier parks and ecological habitats
- Improving overall coastal resiliency to part of Delaware’s widely popular inland bay system
Marsh Restoration
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 the 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.
Beneficial Use Cells in the Muddy Neck Marsh Complex
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 the 122 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 and has been done in Delaware. In 2013, DNREC’s Shoreline and Waterway Management Section and Wetlands Monitoring and Assessment Program joined together 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.
Project Timeline
Currently, this project is in the construction phase.
Tree trimming and the removal of woody and marine debris from the project area is to be completed in addition to the dredging. This work is to begin in early December of 2024.
Mobilization of the dredge and placement of the pipeline is complete. Dredging will be performed concurrent with tree trimming. It will begin in White Creek following completion of pipeline booster pump placement as well as tree trimming. This is scheduled to occur around the New Year.
Dredging will be performed from the mouth of White Creek working toward the Assawoman Canal. This will allow pipe to be removed as the project progresses. Completion of the Assawoman Canal is expected by the end of March 2024.
Permit conditions require the dredging project to be completed by the end of March to minimize impacts to hibernating terrapins. Demobilization is scheduled to last until late April.
The project area will be monitored by DNREC through 2028.
For more information, please contact Joseph Faries at 302-900-1546.
