In very hard sediments, milfoil plants tend to break off leaving the roots behind and defeating the purpose of diver dredging. Diver dredging has been used in British Columbia, Washington, and Idaho to remove early infestations of Eurasian watermilfoil. Diver dredging is less effective on plants where seeds, turions, or tubers remain in the sediments to sprout the next growing season. For that reason, Eurasian watermilfoil is generally the target plant for removal during diver dredging operations. Advantages Diver dredging can be a very selective technique for removing pioneer colonies of Eurasian watermilfoil.
Divers can remove plants around docks and in other difficult to reach areas.
Diver dredging can be used in situations where herbicide use is not an option for aquatic plant management. Disadvantages Diver dredging is very expensive. Dredging stirs up sediments. This may lead to the release of nutrients or long-buried toxic materials into the water column. The tops of plants growing in rocky or hard sediments may removed leaving a viable root crown behind to initiate growth.