3D Dredger Team

3 D Dredger Team™  – (Prometheus Innovations LLC and Hydro Maintenance Service)

The 3 D Dredger™ (3DD) is a fully autonomous dredging system created by Swiss engineering firm Hydro Maintenance Service and developed in collaboration with Prometheus Innovations, LLC. The 3DD is designed to handle any sediment composition as well as larger debris using a selection of three dredging attachments. The system is designed for deployment in any environment and water body geometry, without impacting facility operation nor recreational activities. The system operates over a programmed path utilizing a real-time kinematic global navigation satellite system coupled with an inertial navigation system to monitor its position and movement around a moored pattern. The system can incorporate an on-board bathymetric mapping system to determine progress of sediment excavation. The fundamental goal behind development is to create a sediment removal solution capable of restoring both the original basin geometry as well as the downstream sediment distribution to pre-facility sediment loads without negatively impacting the environment.

System Operations and Capabilities The system is a small footprint, modular, portable design with a triangular footprint of 26 feet per side, a height of 16 feet, and a draft of 6 feet. A 3D render of the floating platform is provided in Figure 1.

Figure 1: 3D Render of the 3 D Dredger™ System’s Initial Floating Platform Design

… the system can only be deployed in areas of 100 ft x 100 ft at minimum; however, as the dredging template can consist of any number of anchor positions, no upper limit to the size of the dredged area exists. Therefore, the system is capable of managing sediment in a reservoir of any size and geometric configuration.

Total Packages and Depth Capabilities
The 3DD is designed to remove sediment and debris material using one of three attachments fitted to a vertical winching system on the bottom of the central column of the floating platform deployment. …

These dredging tools are capable of operating in water depths ranging from 12 feet to 650 feet and are each designed with a specific purpose in mind. …

Overview of Application at Lewis and Clark Lake/Gavins Point Dam
The 3 D Dredger™ sediment management solution has an application for the sediment issues at the Lewis and Clark dam reservoir because it is a system that is intended for semi-permanent installation so that it can be utilized by the owner to continuously, on a short period activation, work to manage sediment inflow. The 3 D Dredger™ has a floating unit and separator price point in the range of a single conventional dredging spread mobilization and because it is a robotic, autonomous system, it does not require a crew complement other than a single observer for control oversight. The cost of the floating platform and hopper/separator system includes installation and training for the owner’s staff and HM Service provides support and maintenance on demand for situations that arise that are beyond the capabilities of owner trained staff.

In a very high-level general overview, we estimate that the 3 D Dredger™ will need to be activated approximately every 90 days and operate for a 30-to-45-day period to manage the sediment inflow of 4 million yd3 per year. This assumes a fairly constant sediment inflow which is not likely so this will need to be adjusted to accommodate periods of higher and lower sediment inflow.

The 3 D Dredger™ sediment management solution seems like it would be the most cost-effective solution for the Lewis and Clark dam reservoir and can be scaled up if desired by the owner to achieve original basin geometry in a short duration effort and also manage sedimentation upstream and downstream at critical points simultaneously in a cost-effective manner. This is simply done by adding 3 D Dredger™ units. This is an option to consider but the owner should also be aware that the 3 D Dredger™ is a modular unit and portable with modular transport in five Conex containers that can be carried by truck, train or barge so that the system can be deployed easily at various locations along the stream trace where shoaling is desired to be managed.

This method of sediment management could extend the lifespan of the reservoir indefinitely while also restoring the streamflow sediment condition in the downstream environment, providing a holistic approach to basin restoration and sediment management with an incorporation of the technology into the regular general operation and maintenance of the reservoir, dam, and stream.

We are currently in negotiations with a major international shipbuilder to fabricate and construct the 3 D Dredger™ system at one of its US shipbuilding sites under license from our organization and should have an agreement in place by early 2023. This will shorten the delivery time for the system as well as potentially reduce costs. …

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