An important part of the DNREC Division of Watershed Stewardship’s mission is to maintain and improve Delaware’s navigable waterways, including its bays and canals.
The Shoreline and Waterway Management Section oversees a range of waterway management activities throughout the state. They include dredging and marking navigation channels that are not maintained and marked by the federal government and removing nuisance macroalgae and navigation hazards to preserve, maintain and enhance recreational use of the State’s waters.
The section oversees and provides guidance and planning for dredging projects in important Delaware waterways.
As part of this role, the section carefully manages the sediment dredged from navigational channels as an important natural resource to beneficially use the sediment for beach nourishment or ecosystem restoration.
It also provides aids to navigation, including channel marking, macroalgae management and tax lagoons.
Pilottown Road Mitigation Study — an investigation of flood mitigation options for a flood-prone section of Pilottown Road, in Lewes.
The section helps communities manage their flood risk and stay in compliance with National Flood Insurance Program Regulations for floodplain development. It helps to update and improve federal floodplain maps.
The Delaware Dam Safety Program works to reduce the risk of dam failures and the resulting consequences. It oversees the design and construction, operation and maintenance, and inspection of regulated dams in Delaware and provides resources for the community and dam owners.
The Shoreline and Waterway Management Section submits a report each year to the Joint Legislative Committee on the Capital Improvement Program, as required by epilogue to each fiscal year’s Bond and Capital Improvements Act. The act epilogue states “DNREC shall provide a report of the projects, priority rankings, and timelines for completion of the dredging, navigation, and channel marking related projects within the Inland Bays to the Joint Legislative Committee on the Capital Improvement Program by September 1st of each year.”
Statewide Dredging Policy Framework (2001)
Rehoboth Bay Sediment Management Plan and Appendices (2007)
The section conducts waterway management activities throughout the year on a seasonal schedule.
Dredging – Two state-operated dredges, the Seidel and Mispillion, operate during the late fall to early spring, when environmental conditions allow for dredging. State dredges are suited for targeted dredging of small problem areas in channels, and maintenance of state marinas and boat ramps.
Channel Marking – The section is responsible for setting and maintaining almost 200 individual channel markers in nine channels.
Nuisance Macroalgae Harvesting – The section manages excess algae growth that can become an environmental concern and cause harm. Nuisance macroalgae peaks in June and July and can be harvested with two unique macro-algae harvesters.
Navigation Hazard Removal – Debris, downed trees, derelict vessels, and other hazards are removed throughout the year as needed.
Depth Surveys – Depth surveys of state-maintained waterways are updated periodically to evaluate conditions and measure shoaling.
For large or complex dredging projects, the Shoreline and Waterway Management Section works with hired contractors. A contracted consulting engineering firm handles the design, permitting and construction management, and a contracted dredge company performs the dredging.
The same is true for large or complex waterway management projects aimed at reducing the need for dredging. Jetties and other features that change the way currents move sediment into navigation channels have been designed by contracted engineers and built by qualified marine contractors.
The section selects and plans for future dredging projects using an annual prioritization process.
DNREC has begun a project to replace and rehabilitate the jetties at the entrance of the Murderkill River. This project will replace or rehabilitate the southern jetty as well as the unrehabilitated section of the north jetty. It will also repair the scour inland of this section through beach nourishment.
Work is set to begin in the fall of 2023 on dredging the navigational channel along the Indian River, near Millsboro. The material dredged from the channel will be used in a marsh enhancement project to restore a local wetland area.
This project addresses impaired emergency vessel docking at the Delaware City Branch Canal in New Castle County. The permitting phase for this project is underway currently. Federal authorization has been obtained, and the state Wetlands and Subaqueous Lands permit application has been submitted and is in process. This project is expected to be performed by the state dredge and crew in the winter of 2021 to 2022.
The Lewes and Rehoboth Canal located west of Rehoboth Beach is popular among recreational boaters and connects the Inland Bays with Delaware Bay. The section is coordinating with U.S. Army Corps of Engineers to understand the potential for federal participation in maintenance while this channel remains on the long-term (2024 to 2025) planning portfolio.
The DNREC Divisions of Watershed Stewardship, Parks and Recreation and Fish and Wildlife work together to maintain public boat access sites such as: Indian River Marina, Augustine Beach Wildlife Area boat ramp and Holts Landing.
These sites are dredged as-needed (typically 1 to 5 years) using state equipment and crews. Indian River Marina and Augustine Beach Wildlife Area boat ramp are expected to be dredged in the 2022 to 2023 timeframe. A survey of the Holts Landing boat ramp approach in August 2021 showed only incremental depth changes since the previous dredging 5 years ago. Holts Landing will need to be maintenance dredged again, likely in the 2024 to 2025 timeframe.
DNREC began a project to dredge the main channel of White Creek and parts of The Assawoman Canal in 2023. Work on the project was completed in summer 2024. Channel maintenance for White Creek and the Assawoman Canal, near Bethany Beach in Sussex County, was identified as a high priority in a dredging project prioritization study. Since dredging last occurred in the early 2000s, shoaling had increasingly impacted navigation in the waterways.
Emergency Murderkill River Inlet Dredging: DNREC completed an emergency dredging project at the mouth of the Murderkill River to deepen the channel to regain safe, navigable access to the Murderkill River at all tide levels.
Murderkill River Maintenance Dredging: In the spring of 2022, DNREC completed a small-scale dredging project on the waterway.
Indian River Marina: Section crews used the state-owned swinging dragon dredge to complete this project in winter 2021.
Massey’s Ditch: The channel was dredged to a width of 100 feet and a depth of 7.5 feet below Mean Lower Low Water (MLLW). A contractor removed approximately 140,000 cubic yards of material from the channel and adjacent areas. These included the entrance to Baker’s Channel, on the north side of Lynch Thicket Island, and a large shoal between the south end of Lynch Thicket Island and Middle Island.
Augustine Beach Boat Ramp: Section crews used the state-owned dredge Seidel to remove 2,000 cubic yards of shoaled sediment.
Indian River near Millsboro: Section crews used the state-owned dredge Seidel to remove 20,000 cubic yards of shoaled sediment from the navigation channel.
Indian River Inlet Marina: Section crews used the state-owned dredge Mispillion to remove 1,500 cubic yards of shoaled sediment.
Augustine Beach Boat Ramp: Section crews used the state-owned dredge Seidel to remove 2,000 cubic yards of shoaled sediment.
Lightship Overfalls: The goal of the Overfalls project was to dredge the entire berthing slip located in Lewes in Sussex County to a depth of nine feet below mean low tide using the state-owned dredge Mispillion. The timeframe called for accomplishing this while the lightship was offsite for repairs in New Jersey. This work was performed by the state under contract with the Overfalls Foundation; the state no longer performs contract dredging to focus on maintenance of public navigation channels.
Indian River near Millsboro: Section crews dredged 20,000 cubic yards of sediment from this section of the river using the state-owned dredge Seidel.
Navigation Hazards include derelict structures, trees, and other debris within or near to navigation channels which present a safety concern. The section uses a variety of equipment to remove navigation hazards, including a small excavator mounted atop a barge. For large or complex hazards, the section works with qualified marine contractors to remove the hazard.
As an example of other waterways projects, the Shoreline and Waterway Management crew recently responded to a derelict barge complaint in White Creek. The barge was towed to the Indian River Marina and removed from the water. Previously, the section worked with Manson Construction to remove a derelict dock near the intersection of the Broadkill River and the Roosevelt Inlet. The dock was deemed a hazard to navigation due to its location and would become a further hazard as it degrades and parts of it would begin to break off and float in local waterways.
The section uses a data-based prioritization process to rank channels. The process incorporated public feedback through workshops and a survey.
Timelines for dredging projects vary, but it is not unusual for a project to take multiple years to undergo the full process of planning, engineering, design, permitting, construction, and post-construction monitoring.
Each project varies in cost. All projects undergo rigorous engineering, design, and permitting processes. A general range for large (20,000 cubic yards or greater) projects is $3 to $5 million per project.
Environmental Windows are times of year when dredging is expected to have minimal adverse effects on the surrounding environment including fish and wildlife. You might also hear the terms “dredging season” or “time of year restrictions (TOYR)” to refer to the Environmental Window for dredging.
The typical Environmental Window for dredging in the Delaware Inland Bays allows for dredging between October and March. In other words, no dredging can occur from April to September.