Over time, all ponds will collect silt, soil and other material carried in from any number of sources, including local waterways. Even if you have a stream leading out from your pond, much of the load brought in will settle in the relatively calm water.. Stormwater that flows in from surrounding areas can also carry large amounts of soil, sand and gravel. Erosion triggered by stormwater events can even collapse steep banks and add to the load. Over time, all this silt, clay, soil and other detritus will build up until your 12’ pond is only 10’ deep and 20’ wide instead of 30!. Generally, this takes decades to happen, but once the signs become evident, you’ll definitely notice a declining fish population and a less attractive feature. Adding insult to injury, your property value may decline as well - most people prefer to look over pristine ponds instead of swamps full of imagined mosquitoes. Unless you’re aiming to slowly convert your pond to a marshy wetland, it’s time to dredge!
Before you start investing a lot of time and money into the project, it’s a good idea to check with your local and state authorities about any ordinances that affect your ability to dredge your pond, particularly if yours is fed by or flows into a natural waterway. If your pond has shrunk so far that you could call it a wetland, it may actually have acquired protected status. The state’s Department of Natural Resources or your county extension agent can probably point you in the right direction. Once you’ve figured out how to navigate the bureaucratic maze, it’s time to talk technique. Artificial ponds may have been constructed with a liner to help them retain water. Whether the liner is formed by natural clay or a geotextile product, you’ll need to be extremely careful not to puncture or damage it. Additionally, a bentonite clay liner must not be allowed to dry out or it will develop cracks and lose its water retaining ability. In those cases, you’ll need to employ hydraulic dredging, which is essentially an enormous pond vacuum. The equipment is expensive and requires skill to operate without damaging your liner, so it’s best to hire an experienced contractor. If your natural pond is extremely shallow or has no fish population you want to maintain, dry earth removal is a less expensive option to hydraulic dredging. You can breach your dam or dig a trench allowing the water to drain away completely. Once the mud has dried enough that it won’t swallow heavy equipment, a bulldozer or excavator can quickly accomplish the chore. Whichever method you use, you’ll need to decide what to do with the soil you’ve removed. Remember, it will be extremely fertile, so a nice option is to use it in your garden or to fertilize trees and plantings around your property.
