Mechanical Dredging vs. Hydraulic Dredging
When trying to determine how to dredge it is useful to consider the benefits of both hydraulic dredging and mechanical dredging:
Hydraulic Dredging Benefits:
- Easier access to all parts of the dredging area: Dredge pumps on barges can access anywhere there is water to float the barge. Long reach excavators need large open spaces to work.
- Ability to work while pond is in service: If the pond cannot be completely drained, an excavator cannot access all of the pond. If the influent to the pond cannot be closed, hydraulic dredging is the route to take.
- Lined ponds: Long reach excavators can damage clay or hdpe liners to ponds. Hydraulic dredges can take measures to restrict contact with pond liners.
- Dewatering: If there is not space next to the dredging area for the spoils to passively dewater, mechanical dredges will not work as effectively as a hydraulic dredge. Hydraulic dredges can pump spoils to a dewatering area.
Mechanical Dredging Benefits:
- Larger solids removal: If there is ample space for passive dewatering, an excavator can remove a larger amount of solids at one time.
- Cost: If a "dig and haul" approach is possible, mechanical dredging is cheaper. However, this approach can often leave a mess on the road when transporting spoils.