What is the purpose of maintenance dredging?
Maintenance dredging is predominantly used as a means of maintaining required depths for boats and ships to safely traverse navigation channels. Because water is always moving and naturally carrying materials that settle and need to be dredged, maintenance dredging is a constant, cyclical process of upkeep.

​

How is maintenance dredging done?
There are two common types of dredging used in this case: mechanical and hydraulic. Hydraulic dredging uses a larger cutter head attached to a pump that slurries up sand and water, sucks it up, and pumps it upwards of miles away to a disposal area. With mechanical dredging work, large cranes or excavators on a barge physically reach down, remove material, and place it into a material barge. It is then transported to a disposal site or placed in a confined disposal facility. 

​

What are the different types of dredges? 
Some examples of hydraulic dredges include those with cutter suction, rotary cutter heads, auger style heads, those with submersible pump attachments for excavators, and all-hydraulic suction dredges.

Generally for mechanical dredging, we use a clamshell dredge and environmental buckets. Hoppers are an example of ocean-going dredging vessels. 

​

Where does the dredged material go?
This is generally the toughest question that needs to be answered before a dredging project can begin - especially in the private sector. The cost of disposal of dredged sediments can often be higher than the cost of dredging if the materials need to be re-handled, trucked, or sent to a landfill for disposal. The best option is to work with a qualified contractor or an engineer to find a beneficial reuse for the materials and to help you navigate the environmental regulatory requirements of doing so. 

​

As an example, dredged sand and organic material can be piped to beaches and riverfronts to replenish them in the face of erosion - this is called beach nourishment. Alternatively, the materials are often taken to confined disposal facilities, maintained dump sites in the ocean, or can be used in farming if it passes regulatory analytical testing. In some parts of the world, it can be used to create offshore islands or structures.

​

Does dredging reduce flooding?
Dredging can certainly reduce flooding in the right circumstances. For example, storms can push sand into rivers, forming a dam that restricts flow, causing backups and subsequent flooding upstream. This is an even larger concern for smaller creeks and waterways as these can get dammed off and start rising quickly. 

​

Are there other benefits to dredging?
There are numerous commercial benefits to dredging. Maintaining adequate draft for both commercial shipping traffic and pleasure craft is vital to the United State’s and local economies. In addition, there are often environmental reasons that dredging can be beneficial as well. As an example, lakes that have too much unmanaged sediment can become too shallow over time. This will often lead to lakes becoming atrophic which can lead to the death of the fish and other aquatic life in the lake. One of the ways this is combated is by dredging sediment from the lake to maintain a healthy depth. 

​

In addition, dredged materials can be used for beach nourishment, and clean materials are often pulled up and used for other purposes. Clean dredge materials can even be used as a component of larger environmental remediation projects.

​

How can I schedule a consultation for maintenance dredging?
Call Marblehead Dredging & Marina Services! There are specific challenges to every project. The most overlooked component of private dredging projects is what to do with the dredged material. The second is access issues - we need to ensure our equipment can safely access the site. Working on sites with limited access is one of our specialties, and we are able to work around the country with our highly mobile fleet of dredging equipment.