Dredging jobs can be performed on ponds from the shoreline, on barges for large projects, or in a lake or lagoon that has been drained of water. River dredging jobs deepen channels when the routes become shallow from sediment, which can hamper use by boats. Hard rock dredging jobs involve removing rock after it has been broken up by blasting with explosives.
Cranes, backhoes, and buckets are used to remove silt or aquatic growth clogging a river used for navigation or a lake where water quality and clarity are declining. The digging equipment removes the silt or excess plant growth at the bottom of the body of water to reclaim its use. Sometimes the sand or sediment that is removed is used to restore beaches or to elevate land before construction projects begin.
Hydraulic excavation of small lakes or ponds can usually be accomplished from shore. A portable dredging machine with an extended-reach crane can be used on these types of dredging jobs. This type of machine can be effective at golf courses when a pond used for irrigation becomes shallow from water run-off carrying topsoil. On some pond or small lake projects, the basin is drained and allowed to dry up before heavy equipment is used to deepen the area.
Barges outfitted with cranes and buckets are usually used in shipping channels. Accumulated soil or sand is removed with earth movers and loaded onto a second barge, which takes the sediment to the shoreline. The silt is either dumped offshore or loaded into trucks for storage at a designated area.
Some minor dredging jobs can be done with portable hydraulic devices. These floating dredgers suck soil from the bottom and carry it through a temporary pipe to an off-site location. Only two trips are necessary into the water — one to set up the equipment and another to remove it when the project is done.
Waterways and lakes can become shallow over the years by a natural process known as eutrophication. Silt or other sediment builds up over time to restrict shipping channels or reduce the depth of lakes or man-made reservoirs. Natural disasters that cause excessive run-off, and construction projects without silt control measures in place, can escalate eutrophication. The process can lead to a decline in the value of waterfront property and decrease the amount of water available for drinking or irrigation.
People seeking dredging jobs can often get training from heavy equipment companies that receive contracts on private or public work projects. Some operators work 12-hour shifts and may be needed for overtime if emergency work is required for flood prevention. Travel is often a required part of working on a dredging crew, and a dredging employee may have to endure adverse weather conditions at job sites.