Frequently Asked Questions
Yes, docks are permitted to be dredged on reservoirs and lakes. However, each lake’s manager or owner has requirements of how and when a dock can be dredged. The US Army Corps of Engineers, Georgia Power, and TVA differ in requirements and dredging permits from each lake.
Yes, according to www.georgiapowerlakes.com:
- “Georgia Power is authorized to permit dredging of up to 500 cubic yards per property. Greater amounts will require further approval from the U.S. Army Corps of Engineers, FERC and additional agencies.
- Dredging plans must be submitted and approved before work can commence.
- Georgia Power may exercise the option to require a certified engineer or surveyor verify the scope of the project at our sole discretion.
- Removal of original lakebed/river bottom is prohibited. The sole purpose of dredging is to remove sedimentation/organic materials that have accumulated over time.
- A turbidity barrier must be installed within the lake area for containment and equipment being used must work inside this barrier.
- Silt must be either transported from site or pumped to a location off GPC property and/or project lands, or a minimum of 25′ from lake, whichever is greater. Material cannot be used to backfill seawalls or to “level up” land.
- Silt/sediment removed must be stabilized in a way to avoid re-entry into the lake and to not to impact GPC property.
- At Lake Jackson, it may be necessary to execute a property line agreement prior to dredging activity to establish pre- and post-dredging property rights.
- Dredging of wetland areas or for the purpose of removing upland materials via “channeling” to create additional shoreline is strictly prohibited.
- Upon receiving a dredging permit from GPC, the permittee agrees to:
- Abide by all government rules, laws, regulations, directives and statutes.
- Acquire all necessary governmental permits or licenses, which may include, but not be limited to, a land disturbance permit.”
It may vary significantly, but you can find out. One way is to hire a professional, but if you just want a general idea there are many methods to probe. Depending on the sediment type you can use a piece of pvc pipe, rebar, broom handle, or other probe to push and work up and down throught the muck until you feel resistance that is the bottom. Some really fine, consolidated sediment may not let you probe all the water through it but you will have an idea of the depth.
A sediment survey or bathymetric survey can help determine the amount of sediment within a lake. Surveys involved finding the top of sediment and the bottom with a probe to determine the sediment depth in a particular location. That location can be used to determine an area to calculate a volume. Sediment is typically measured in cubic yards. Sludge is usually measured in dry tons.
There are a lot of products that claim to get rid of silt or muck from the bottom of your lake or pond. Some products attempt to resuspend the silt. Some attempt to re-aerate the silt. Some products try to decompose it. However, most silt removal is very limited with these techniques. Dredging is a proven solution to removing silt from your lake or pond. Dredging can be done by digging the silt out or pumping the silt from the lake or pond.
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.
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.
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.
Small hand operated dredges can be purchased for as little as $15,000, but they are only effective for limited types of projects and sediment. The smaller dredge barges can be purchased for $100,000 to $150,000. As you increase in size and effectiveness, most portable dredges cost between $500,000 and $2,000,000. The cost only increases for dredges bigger and with more features extending through the millions and for the largest dredges into the tens of millions. Auxiliary equipment and pipeline are an additional expense that needs to be considered as well in the cost of purchasing a dredge.