Mechanical Dredging

Conventional methods utilizing draglines and backhoes generally cause a lot of destruction of the landscape. We have found that estimates for removal of sediment using this method typically runs about 50% or more above the cost of our sediment removal system. You must drain the pond and then try to handle and haul the sediment slurry that is dug out. The impact in most cases is severe and restoration is expensive. It can also destroy any fish population you do have.

Diver Assisted Pumping

In small ponds and extremely tight situations this is an option that we utilize as needed. However in most cases it is inefficient and causes excessive turbidity in the water.

 

Hydraulic Dredging

Hydraulic dredging is the method we have found to be the most effective in the majority of the projects we see. The dredge is basically a pump and a collection system mounted on a small boat built for the purpose of dredging. All you see and hear of the operation is something the size of a pontoon boat floating on the water and a very quiet diesel engine.

 

The pump pulls the material off the bottom and pumps it through a pipe to locations that can be nearby or up to several thousand feet away. Temporary pipe is laid to the disposal location. Pipelines can be installed under roads or walkways or temporary ramps can be built if needed.

 

Other Methods

There other methods that are recommended at times but are either ineffective for significant sediment build up.

 

Chemical Treatments - For light deposits in small ponds these may help. You simply can not make matter disappear. Some organic material may be consumed, but it is insignificant.

 

Alum - Treatment of organic sediment with Alum has been used to lock up the nutrients such as phosphorus. This is simply a coat of paint on a problem that will not go away.

 

Aeration - Aeration can help to a small degree, but again will not make significant deposits go away. None of the above have any effect on mineral sediment such as sand and other mineral soils.

A professional aquatic management firm will guide you on the proper use of these controls in situations where they will be of value.

In hydraulic dredging, water is used as a carrier to move the material. The sediment and the water must be separated and the water either returned to the body of water being dredged or left to settle or evaporate. In hydraulic dredging, water is used as a carrier to move the material. The sediment and the water must be separated and the water either returned to the body of water being dredged or left to settle or evaporate.

 

There are several methods that are commonly used:

 

Settling Basin - Try to find a photo we can use of a dredging project with a spoils area. Building a settling basin is typically the most cost effective method to dispose of the dredged material. Your project must have a site large enough to build the basin and it needs to be within a reasonable distance. In some cases natural depressions give an opportunity to utilize an existing land feature to dispose of the material. There may be a need to return the water to the dredge location with an additional pipe.This is a temporary facility and can easily be restored after use. In some case the material dredged has a value as a topsoil or compost amendment.

 

Geotextile Bags - Where there is limited area to create a disposal site geotextile bags can be used to contain the material. The sediment is pumped into bags where the sediment is trapped and clear water is released from the bag to be returned to the pond or lake. These bags are sized for the project. Bags can be as large as 45-60' in circumference and 100-300; long. This method is commonly used on projects such as subdivisions and golf courses. Once the bags are full and have had a chance to dry out they are opened and the material can be hauled away or utilized on site.

 

 

Mechanical Dewatering Systems - Mechanical dewatering is accomplished using various techniques. Typically this is more expensive than the other options but it does offer the ability to haul the material as it is being dredged. This works in situations where there simply is not room to put the material.