Dredging Alternative: Hydro-raking to Increase Stormwater Pond Depth
July 31st, 2017
Written by Industry Expert Emily Walsh, Environmental Scientist
As communities continue to expand and infrastructure is heightened, stormwater management is becoming a crucial element in neighborhood planning. Oftentimes, community developers incorporate stormwater retention ponds into their plans to help control runoff during significant rain events. Retention or stormwater ponds look similar to natural ponds, except that their major function is to reduce the risk of flooding as well as filter collected pollutants.
Urban runoff is led to the pond through a series of stormwater drains leading to underground pipes. The majority of the water is then left within the stormwater BMP, allowing suspended particulates to settle and pollutants to break down through microbial activity and plant uptake. The water is then slowly released from an outflow pipe, positioned higher than the inflow pipe, to a nearby waterbody or stream. This has proven to be an efficient technique, with a detectable decrease in pollutants shown and a natural outflow rate achieved.
Can hydro-raking be an annual management service?
As the retention pond continually cycles the surrounding stormwater runoff, the organic layer along the ponds bottom annually increases – inevitably requiring maintenance. Mechanical hydro-raking is an ideal management option often utilized to remove the accumulated organic material settled along the benthic layer. The hydro-rake can restore pond depth to its original dimensions, resulting in increased overall function and flood retention capabilities. In addition to restoring the function of the pond, the hydro-rake can aid in the removal of organic matter that may be blocking the inlet or outlet structure.
The hydro-rake requires about 1.5 feet of water to operate efficiently, and can successfully remove organic matter ranging from a few inches to a maximum of 10 feet. Each rake full can range from 300 lbs. to 500 lbs. depending on the compositional makeup of the substance. The duration of each hydro-rake project varies depending on the specific management objectives.
Hydro-raking is a more ecological and economical alternative, when compared to lake and pond dredging. The York Rake attachment allows aquatic organisms to escape, whereas wet or dry dredging with an excavator may permanently remove aquatic life. In addition, dredging is often times affiliated with higher permitting and operational costs. Hydro-raking is also valued for its ability operate without affecting shoreline stabalization. Having a back hoe and the capacity to float allows the hydro-rake to off-load material up to 6 feet from the water’s edge, prior to being transferred to a compost facility. Furthermore, the hydraulic system of the hydro-rake is powered by bio-fluid, which is a renewable, bio-degradable and non-toxic substance.
Stormwater ponds are valued assets to communities and their flood retention capabilities are unparalleled. When the time does come to remove accumulated sediment from your pond in order to keep it functioning properly, consider hydro-raking as an environmentally and budget-friendly solution. For now, remember that a proactive lake or pond management plan can help prolong the need for these costlier expenses to your stormwater BMP.
Contact the experts at 888-480-LAKE (5253) for all of your lake, pond and fisheries management needs.
Emily Walsh is an Environmental Scientist with SOLitude Lake Management who assists the mechanical division with invasive weed control services, surveys, reports, proposals and GIS mapping. She is currently licensed to apply pesticides in Massachusetts and Connecticut. She also has experience in terrestrial invasive species applications, particularly Common Reed (Phragmites australis) and Japanese Knotweed (Fallopia japonica), along with aquatic nuisance vegetation applications.
SOLitude Lake Management is committed to providing full service lake and pond management services that improve water quality, preserve natural resources, and reduce our environmental footprint. Our services include lake, pond and fisheries management programs, algae and aquatic weed control, mechanical harvesting, hydro-raking, installation and maintenance of fountains and aeration systems, water quality testing and restoration, bathymetry, lake vegetation studies, biological assessments, habitat assessments, invasive species management and nuisance wildlife management. Services, consulting and aquatic products are available to clients nationwide, including homeowners associations, multi-family and apartment communities, golf courses, commercial developments, ranches, private landowners, reservoirs, recreational and public lakes, municipalities, parks, and state and federal agencies. Learn more about SOLitude Lake Management and purchase products at www.solitudelakemanagement.com.