Great Lakes Dredge & Dock Company faced an all-too-common challenge in the world of water resources management: sediment-filled dewatering ditches that had refilled after initial excavation. Working on a major dredging project in Argenta, Illinois, the company needed an efficient solution for cleaning out 6,000 linear feet of perimeter ditches and connecting standing water pockets. The answer came in the form of a specialized attachment designed to chew through sediment and project it away from the ditch, eliminating the need for hauling material off site. This case study explores how the Ditch Doctor attachment from Ransome Attachments delivered remarkable results and what contractors can learn about modern approaches to coastal and port engineering wave mechanics sediment transport and ditch maintenance on large-scale water projects.
The Challenge of Sediment-Filled Dewatering Ditches
Large-scale dredging projects generate massive volumes of sediment that must be managed through carefully designed dewatering systems. When sediment-laden water is pumped into settling basins, the solids settle out and the clarified water is returned to the source. The ditches that carry this water through the settling process require regular maintenance to remain functional. In the case of the Oakley Settling Basin project, the contractor faced a situation where previously dug ditches had completely refilled with sediment due to the viscous nature of the material being handled.
Lake Decatur Dredging Project Overview
The City of Decatur contracted Great Lakes Dredge & Dock in April 2020 to dredge sediment from the 3,093-acre Lake Decatur. The primary objective was to increase storage capacity for the local drinking water supply. After completing the initial dredging work in November 2019, the contractor returned to the Oakley Settling Basin to finish dewatering ditches and landscaping. The overall goal was to install drain tiles and create properly graded ditches that would eliminate standing water and allow the land to eventually return to productive farmland.
Why Ditches Refill with Sediment
When working with fine-grained materials such as clays, silts, and organic sediments, the viscosity of the slurry plays a major role in ditch stability. The ditches at the Oakley Settling Basin were originally cut in mid-2019, but over time they refilled as the sediment slurry flowed back into the excavated channels. This phenomenon is common in settling basin operations where the water table remains high and the sediment load is continuous. Project Superintendent Tim Cantwell explained that the scope included 6,000 feet of perimeter ditches plus new ditches to connect standing pockets of water, making efficient ditch maintenance critical to the project timeline.
How the Ditch Doctor Attachment Works
The Ditch Doctor is a ditch maintenance attachment engineered to address the specific challenge of cleaning sediment from existing ditches. Unlike a conventional ditching bucket that digs, lifts, and requires off-site hauling, the Ditch Doctor uses a rotating cutting head to chew through sediment, mix it with available water to create a slurry, and project the material through a discharge chute away from the ditch. This approach can be thought of as a snowblower for sediment, as Cantwell described it: it cleans out ditches that have filled in and blows the material clear.
Mechanism of Action: Cutting, Slurrying, and Projecting
The attachment operates through a three-stage process:
- Cutting: Rotary cutting heads break up consolidated sediment, clay, and organic material at the bottom of the ditch.
- Slurrying: The material mixes with water present in the ditch to form a pumpable slurry. This step is critical for efficient projection and requires adequate water content.
- Projecting: An internal scroll mechanism forces the slurry through a discharge chute that throws the material away from the ditch, typically 10 to 30 feet depending on conditions.
Great Lakes mounted the 22-inch Ditch Doctor on a Cat 324DL Long Reach Excavator. The excavator operator maintained full control over cutting depth and projection distance by adjusting the RPM output of the attachment. This allowed the crew to fine-tune performance based on the changing conditions encountered along the ditch network.
Wet Scroll Case vs. Dry Scroll Case
Ransome Attachments offers the Ditch Doctor with two scroll case configurations to handle different water conditions:
| Feature | Wet Scroll Case | Dry Scroll Case |
|---|---|---|
| Maximum water depth | Up to 3 feet | 1 foot or less |
| Best suited for | Puddled water, mucky clay mixtures | Well-drained or shallow ditches |
| Material handling | Clays, organics, rocks, sediment slurry | Drier soil, loose sediment |
| Projection performance | 25-30 ft with high water content | Shorter projection distance |
Great Lakes selected the detachable wet scroll case because most of the ditches contained a mucky combination of clays and organic materials with puddled water, minimal vegetation on top, and rocks that had settled on the bottom. The wet scroll case permitted effective ditching in up to three feet of water, which was essential for the conditions at the Oakley Settling Basin.
Performance Comparison: Ditch Doctor vs. Conventional Ditching Bucket
Great Lakes had the unique opportunity to run both the Ditch Doctor and a conventional ditching bucket side by side, providing direct performance data for comparison. The company had a custom adapter plate fabricated for the quick coupler so changing attachments was simply a matter of switching out a 70- and 80-millimeter pin. This setup allowed the crew to use each method where it performed best.
Speed and Efficiency Gains
Cantwell reported that under the proper conditions, the Ditch Doctor was at least twice as fast as excavating with a bucket. The key variable was having enough water to slurry the material effectively. While the conventional bucket required the operator to dig, lift, swing, and dump into a truck for off-site hauling, the Ditch Doctor eliminated two of these steps entirely. The material was cut, slurried, and projected directly into the impoundment basin without any truck involvement.
The breakdown of work distribution told a clear story:
- About 80 percent of the work was in previously dug ditches that had filled with sediment, where the Ditch Doctor excelled.
- The remaining 20 percent involved virgin clay for new ditch construction, where the conventional bucket was the better tool.
- The Ditch Doctor handled sediment removal so efficiently that 2,500 linear feet of ditch maintenance was completed within the project schedule.
Material Handling and Site Logistics
One of the most significant advantages of the Ditch Doctor was the elimination of off-site hauling. When using a conventional ditching bucket, the contractor would traditionally use a pump to dewater the trench as much as possible before excavating, then load the wet material into trucks for disposal. The Ditch Doctor bypassed this entire sequence by projecting the material directly into the impoundment basin. The wet slurry self-leveled within 24 hours, requiring no additional grading or compaction. This streamlined the logistics chain and reduced traffic on site, which is particularly valuable when working on environmentally sensitive settling basin projects.
The projection distance varied based on sediment thickness and water content. With high water content, material could be thrown 25 to 30 feet. With thicker, heavier clay mixtures, projection ranged from 10 to 15 feet. This flexibility allowed the operator to adapt to changing conditions without changing equipment, simply by adjusting the RPM output of the attachment. For projects concerned with erosion control for construction sites stabilization practices sediment control and regulatory compliance, this approach also minimized disturbance to surrounding areas by keeping sediment contained within the basin.
Key Considerations for Contractors Evaluating the Ditch Doctor
Great Lakes entered into a rental purchase agreement for the Ditch Doctor but ultimately decided not to purchase the unit after the project concluded. This decision was not based on performance, which Cantwell rated highly, but on the reality that the attachment is a specialized tool suited for specific applications. As Cantwell put it, no fiscally responsible contractor wants expensive equipment sitting idle between projects. Understanding when and where the Ditch Doctor delivers maximum value is essential for making an informed investment decision.
Ideal Conditions and Applications
The Ditch Doctor performs best in these scenarios:
- Maintenance dredging of existing ditches that have refilled with sediment, as opposed to cutting new ditches in virgin ground.
- Projects where sediment can be left on site, such as settling basins, impoundments, or large land application areas.
- Ditches with adequate water content to form a slurry, ideally 6 inches to 3 feet of standing water.
- Environments where minimizing truck traffic and site disturbance is a priority.
- Applications involving fine-grained sediments, clays, silts, and organic materials that flow readily when mixed with water.
The Ditch Doctor also handles material that would challenge a conventional bucket, including rocks that have settled on the bottom of ditches. The cutting heads can break up and pass smaller rocks through the scroll mechanism, and if large boulders are encountered, the attachment can function as a bucket to lift them out of the ditch.
Equipment Compatibility and Setup
Ransome Attachments custom-manufactures the Ditch Doctor to fit specific makes and models of excavators from 5 to 22 tons. Great Lakes used a 22-inch model on a Cat 324DL Long Reach Excavator, which provided the reach needed to access the full width of 10-foot-wide ditches. The custom adapter plate for the quick coupler made attachment changes fast and straightforward, allowing the crew to switch between the Ditch Doctor and the ditching bucket as conditions demanded.
The attachment is available in two models to suit different excavator sizes and project requirements. Both models use the same patented cutting and projection mechanism but are scaled for different hydraulic flow rates and excavator weight classes. For contractors who regularly perform ditch maintenance on large water projects, the Ditch Doctor can be a transformative addition to the equipment fleet. For those who encounter this type of work intermittently, rental arrangements provide a viable path to accessing the technology without a permanent capital commitment. This same principle of matching equipment to application applies across the industry, whether considering specialized construction attachments tools and modern jobsite technologies from quick couplers to autonomous systems or evaluating dedicated sediment management equipment.
The Ditch Doctor represents a specialized but highly effective approach to sediment management in dewatering ditches. By eliminating the need for off-site hauling, reducing equipment cycles, and projecting material directly into containment areas, the attachment offered Great Lakes Dredge & Dock a pathway to faster completion and lower logistical complexity. Understanding the fundamentals of sediment transport and how from sediment dredging to island making sustainable marine development through artificial islands parallels on-land sediment management helps contractors evaluate whether this attachment fits their project needs. For projects with the right conditions, the Ditch Doctor can deliver productivity gains that transform the economics of ditch maintenance.