2,412 Dump Trucks of Sediment Reduced

11 Apr

After the Lake Harmony Association received a report indicating their lake was filling in with sediment, they began looking for solutions to their problem. Dredging would have been far too expensive, so the Lake Harmony Association began looking for alternative options. Enter: Clean-Flo International. Below is the story of how Clean-Flo’s custom designed inversion/destratification and biological treatments reduced 48,239 cubic yards of sediment in the first 4 months.

Getting the System Designed and Installed

Design

The first step in the process is for Clean-Flo to gain a fuller understanding of the environment in which we are working. This is done in 2 main steps – A scan of the lake bottom and sediment samples to know what the bottom is comprised of. Clean-Flo took an initial scan of Lake Harmony using the Lowrance HDS 7 fishfinder/chartplotter with broadband sounder technology, built-in GPS antenna, and high-definition mapping.  The contour maps for the lake along with a color-coded scale are shown below. The scale goes from light blue (shallowest) to dark blue (deepest). The maps contain some of the depth indications by number and are in 1-foot intervals.

The deepest reading obtained in the initial scan was 14.14 feet. The 14’ contour (14’ or greater but less than 15’) was a very small area in 2017. The deepest contour in the eastern section of the lake was 10’ and it was a relatively small area. The 6’ contour barely reached into the northwestern cove area in 2017. The Lake Harmony Association contracted an independent company to collect sediment samples to be analyzed by a laboratory for organic content of the sediment. Sediment is composed of organic matter, inorganic matter and water. The only solution to reducing inorganic matter is dredging. However, if the sediment contains organic matter, it is possible to reduce the sediment without dredging.

Install

Based on the detailed characteristics of the lake, Clean-Flo designed a system with 2 compressors and 24 micro-porous ceramic diffusers. The diffusers are strategically placed using GPS coordinates to maximize the efficiency of the system. The system took 3 days to install and officially started running June 16th 2018.
Along with the inversion/destratification system, Clean-Flo administers biological treatments to the body of water to catalyze the sediment reduction process. The biological additives are equally as important as the inversion/destratification system. Both of these components of Clean-Flo’s service work in tandem to create the impressive results displayed in the latter section of this article.

What happens to the sediment?

To understand what happens to the sediment we must first understand how it gets there in the first place. Organic waste, such as leaves in the fall, is added to the lake each year. This waste sinks to the bottom and decomposes to form organic muck and sediment on the bottom. Year after year this occurs and begins to accumulate. During the process of decomposing this organic matter releases nutrients into the water. Organic sediment on the bottom can be broken down in two ways. Anaerobic digestion or aerobic digestion. If the lake is eutrophic, then anaerobic digestion takes place and this releases nutrients in forms that favor the growth of algae and cyanobacteria (toxic blue green algae). Algae blooms in the summer and the dies off and sinks to the bottom again in winter, where it is added back to that year’s organic accumulation from leaves and other organic matter. This cycle is called nutrient recycling and accelerates on an exponential scale.
If aerobic digestion takes place and is enhanced by enzymatic digestion, then nutrients are released in forms that favor the growth of life-forms that create the foundations of a productive food chain. Nutrients are also supplemented by Clean-Flo to further support these life-forms at the bottom of the food chain. Once the organisms such as zooplankton at the bottom of the food chain proliferate, the food chain “blooms” instead of the algae. Fish size and populations increase as do the predators who feed on the fish. The food chain therefore provides a biochemical metabolic pathway for removal of nutrients and this prevents recycling and the worsening of algae blooms each year. Aerobic digestion is much faster than anaerobic digestion which means that we can digest the sediment much faster than it forms and therefore achieve a net reduction in organic sediment.
In short, Clean-Flo changes the digestion of the organic material on the bottom of the lake from anaerobic (lacking oxygen) to aerobic (having oxygen). The presence of oxygen breaks the cycle of the sediment buildup by incorporating it into the food chain.

Results

Below is a side by side comparison of the depth profiles of the lake. The initial scan was taken on 9/13/17, nine months prior to installation. The second scan was taken on 10/9/18, just shy of 4 months after the system was turned on.

After just 4 months there are noticeable results on the depth increase across the lake. The deepest reading increased from 14.14ft to 14.97ft but this is not the most significant area of depth increase. Whereas the eastern part of the lake had an 8ft depth contour before the Clean-Flo system was installed, the same section of the lake now reached up to 10 ft in depth consistently. As shown in the images below, one can also see how much the 8ft contour line (highlighted with a red line) in the center of the lake has crept north quite substantially.

The numbers are quite substantial as well. The initial scan calculated the water body volume to be 1,122,736.40 cubic yards. In the industry a much more digestible unit called acre-feet is used, and 1,122,736.40 cubic yards equates to 910.09 acre-feet. The second scan of the lake calculated the water volume to be 1,159,620.19 cubic yards, or, 940.12 acre-feet. This concludes that 29.9 acre-feet or 48,239 cubic yards of sediment has been reduced in Lake Harmony.

Additional Benefits of a Clean-Flo System

The Lake Harmony Association contacted Clean-Flo as an alternative to dredging, but the Clean-Flo process has many more benefits than just sediment or muck reduction. Firstly, the system continues to work, whereas dredging is only a temporary fix. Also, sediment reduction directly correlates to the lake bottom hardening. This makes it a much more pedestrian friendly environment. Below is the side by side comparison of Lake Harmony’s bottom hardness. To clarify the technical maps, the yellow refers to soft bottom, the orange refers to medium bottom and the red refers to hard bottom. Another way to think about it, the darker the better.

Soft bottom area decreased by 36%, medium bottom decreased 4%, and hard bottom increased by 35%. As described with the explanation of what happens to the sediment, Clean-Flo changes the lake’s digestion from anaerobic to aerobic which comes with it a plethora of side benefits. Algae growth is reduced. Water clarity goes up. To a fisherman’s delight, the fish also get much healthier and bigger.

Concluding Remarks

After being contacted by the Lake Harmony Association for sediment build up, Clean-Flo installed a system comprised of 24 diffusers. The system was started on June 16th of 2018 and a second scan of the lake bottom was conducted on October 9th of the same year. The second scan showed that Clean-Flo International was able to reduce the muck in Lake Harmony by 29.9 acre-feet or 48,239 cubic yards in the first 4 months of service. To put this in perspective, a tri-axle dump truck holds approximately 20 yards of topsoil. That equates to 2,412 dump trucks full of muck driving away from the lake. Not only has the primary issue been resolved but the ecosystem of the lake is also in a much healthier state leading to algae reduction, increased water quality and clarity, along with better fishing. We sincerely hope the residents and visitors of Lake Harmony enjoy the healthy lake for many years to come. If you are interested in reading more stories such as this one click here and if your body of water needs help contact us here!