Muck can be as nasty as it sounds in your lake. The way to remove muck from your lake depends on how much you have and what kind of muck. Muck rakes can be used to clean up a small portion of muck that gathers along your shoreline or dock. Pumping muck with small trash pumps may work a little but is generally not an effective means as it stops up with sticks and trash easily. You also have to deal with the water you pump from the lake. There are some chemical and biological solutions that aid in decomposing organic matter but not the dirt portion of muck. There are even mats made to walk on it. Ultimately though, the solution to remove muck is to dredge your lake. Dredging can remove muck from any area and restore the lake back to the original depth.
Dredging is the method to remove sediment, silt, and muck from a lake, pond, or lagoon. You can dig the dirt out with an excavator, or you can pump it out with a dredge.
Dredging projects take a few days up to a year to remove sediment. A common question before a project begins is “How long will this dredging last?” or “When will I have to dredge again?” One of the best ways to answer this question is the lake or pond’s history. How long has it been since the lake was dredged last time or if ever since it was created? If it was dredged, was there any record of the quantity removed. The watershed size and characteristics have the most impact on the amount of incoming sediment. Urban areas contribute a lot of stormflow than leads to streambank erosion. Suburban areas may be continuing to be developed leading to increases in both stormflow and sediment entering the watershed. A walk up the tributary can tell a lot about the sediment sources. The best way to track sediment is to perform a bathymetric survey or sediment survey to determine the water and sediment volume at a particular time and repeat the process to evaluate the change. The amount of sediment and water storage lost can be determined accurately and a plan can be developed based on those facts. Other options such as remediation efforts or enforcement of best management practices upstream from the lake can be implemented if severe issues are in the watershed.
Dredging lakes provides numerous benefits for the environment, property owners, and other stakeholders in the watershed:
- Restores water depth (lowers water temperature and improves dissolved oxygen)
- Increases storage quantity (hydropower, stormwater detention)
- Improves water quality (removes excessive nutrients)
- Recreational activities restored (safer boating, skiing, boat docks)
- Better navigation (safety and passage)
- Removes pollution (contaminants and other trash)
- Improves aquatic habitat (removing fine sediment that covers spawning areas)
- Increases water front property values
- Aesthetic improvement
Dredging a lake may cost more than you expect. It takes specialized equipment and personnel to remove and dewater thousands or tens of thousands of cubic yards from a lake. Most people don’t realize how much muck is beneath the lake surface. Removing, transporting, and disposing of wet mud is much more difficult than traditional dirt grading on land. The cost to dredge can be as little as a few dollars per cubic yard for large projects that only pump sludge from one place to another without interruption. However, lake dredging usually involves sediment that changes in type (sandy vs. silty), content (trash, logs, sticks, leaves, rocks, etc.), water depth, and sediment thickness. These factors inhibit the dredge from pumping non-stop and to its peak performance. Dewatering the sediment is often the limiting factor. Limited space, time, and type of sediment slows the process of turning a completely sloppy mud into dirt you can grade or transport efficiently. Therefore, the cost to dredge a lake ranges from $5,000 to $5,000,000. However most projects can have a dramatic impact on a lake within the cost range of $50,000 to $250,000.
Dredging inland lakes is not bad. It is actually beneficial to the environment. Dredging often has a bad reputation from past practices done to drain beneficial wetlands, create beaches, or improve navigation. However, as man-made lakes dammed decades ago fill with sediment the impacts on water quality and quantity are immense. Sediment eliminates natural habitat as it fills areas with lakes and stream beds. Along with sediment, nutrients are transported, retained, and then released during certain conditions. Eutrophication is evidence of this process. Removing the sediment that will never move out of a lake by dredging is a method that reduces the impact of sediment and the nutrients attached to it. Dredging restores the water depth for storage (hydropower and drinking water sources) to prevent drought issues both in the lake and downstream. Dredging removes phosphorus from the water preventing harmful algae blooms. Dredging improves recreational activities along with safety. Dredging removes fine sediment and leaves coarse sediment or cobble and other large woody debris that is suitable for fish and other macroinvertebrates habitat and spawning. So, just remember dredging is not always bad when done with the right purpose!
Lake dredging is done either by excavating the sediment with an excavator (or bucket of some type) or with a hydraulic dredge that sucks the sediment from the bottom of the lake and pumps it through a pipeline to an area outside of the lake. Both methods are very effective ways to remove muck from a lake. Access to the lake is a major factor in considering how to remove sediment from a lake. Disposal of the sediment is the other primary factor involved in determining the method for removing sediment from the lake.
