Check following website for estimate of effects of Hazardous Algal blooms on property values at Buckeye Lake and Grand Lake St. Mary.
Choctaw Lake was built by American Realty Service Corp owned and operated by Ed Wrenn in 1964 where Deer Creek and George’s Fork creeks met. American Realty built over 50 similar lakes in Ohio, Kentucky, Indiana and Illinois, such as Lake Waynoka, Lake Lorelei, Lakengren, Lake Seneca and Lake Mohawk to name a few. The lakes were built as impoundments of existing creeks with a focus placed on selling lake community lots. Generally, the lakes are relatively shallow with low flow characteristics.
Choctaw Lake is in the Deer Creek watershed, which is located in south central Ohio. Deer Creek flows into the Scioto River north of Chillicothe in Ross County. Choctaw Lake is the first stop for water in the Upper Deer Creek watershed. The source of the water is run-off and drainage from 15,616 acres of primarily farmland in Madison, Clark and Champaign Counties. As such, Choctaw acts as a settling pond for sediment suspended in this water. Most of the lake water enters the lake from Deer Creek (48% annual average) and George’s Fork Creek (12% annual average). The remaining 40% of the annual average water into the lake comes from direct impact and local run-off directed by drainage ditches and several small, short local streams. After passing through Choctaw, the water flows down Deer Creek to Madison Lake State Park, and then on down to Deer Creek State Park. The water eventually flows into the Scioto River and then the Ohio River.
Choctaw Lake covers about 285 acres, with all but 13 acres being on the north side of Old Columbus Road. The lake is relatively shallow, with 14 feet being the maximum depth in the pool area in front of the dam. The average lake depth calculates to about 7’ – 7”. The water is held back by an ODNR rated Class 1 dam, 925 feet long and 42 feet max. height. There are approximately 7.5 miles of shoreline around the lake.
(Source: Jim Swihart. “State of the Lake Report, Choctaw Lake.” November, 2015)
Our lake’s microcystin concentration from a sample taken on July 10 was 0.75 parts per billion (ppb). Yeah! That’s great news! And the recent heavy rains likely caused an even lower microcystin concentration.
Ohio EPA requires advisories at two levels of microcystin, and we are far below those levels.
Recreational Public Health Advisory: A sign is posted on beaches when toxin levels exceed 6 ppb warning that an algal bloom is present and/or algal toxins have been detected. Swimming or wading is not recommended for children, pregnant or nursing women, those with certain medical conditions, and pets.
Elevated Recreational Public Health Advisory: A sign is posted on beaches when toxin levels exceed 20 ppb warning that all contact with the water should be avoided and algal toxins at unsafe levels have been detected.
(As an aside, 1.0 ppb is analogous to one sheet in a roll of toilet paper stretching from New York to London or one second of time in 32 years.)
When you drive around the community, you may notice several stream beds and ditches that have overgrown areas. You may have thought to yourself that maintenance wasn’t keeping up with the work out here. Actually, these are areas designed to help keep our lake water clean.
These “riparian zones” provide several benefits. The first one is that these plants stabilize banks. The plants that grow along the edge of the stream actually hold the soil in place very well and help slow down the erosion of the streams and surrounding area. The roots grow deep into the soil and act as a set of fibers holding everything together as seen in this photo.
The second major effect of riparian zones have is that their grasses and plants reduce erosion, which also slows and reduces total sediment flow. These zones can also remove sediment from the water column. During a large water flow, water will rise high enough along the banks that it will move up into the plants and into the riparian zone. Runoff is slowed down greatly and a large amount of the sediment is dropped out into these plants.
The riparian zone has other benefits. The plants that live within the area are heavy users of nitrogen and phosphorus. These plants use and hold nitrogen and phosphorus that flow through these streams and ditches after they leave the farm fields yards. If allowed to grow, these plants can clean a stream of its nitrogen and phosphorus and reduce the load deposited in the lake. These plants also provide areas for microorganisms to thrive and help hold nitrogen and phosphorus in place. These microorganisms also have even been shown to hold some metals from nearby water.
A unique benefit that these riparian zones provide is habitat for a large number of animals including frogs, toads, and other amphibians. They also provide habitat for birds and mammals. These mammals can be smaller rodents, rabbits, and even larger foxes, weasels, beavers, otters and raccoons. Some of these mammals could create problems for road traffic, but they are a great benefit for geese reduction. Raccoons, foxes, and other predators will hunt for and kill the eggs of the geese and duck populations.
The last benefit is that a riparian zone is self-sufficient. Once in place a riparian zone will need almost no real maintenance. The only way in which a riparian zone will change is if humans interfere with it or if an invasive species is introduced to the region. Once in place and left alone, a riparian zone will provide these benefits in perpetuity.
So, if you see workers planting in and along the ditches, know that they are developing riparian zones, which provide cleaner water for our lake along with great habitats for wildlife here at the lake.
(Article contributed by Eric Thomas who is a student intern from Colorado State University and is helping the Water Quality Committee this summer.)
Recent news articles report high harmful algal blooms (HABs) at state park lakes. At Choctaw Lake, 2013 and 2014 were both bad blue-green algae years with microcystin peaking at 17.5 ppb in 2013. But our recent investment in a water quality management program seems to have paid off. Last year, our highest microcystin concentration was 3.4 ppm.
Our recent microcystin reading of 0.1 ppb in mid-June is very good news!
Because microcystin tests are done at a lab and are expensive, we weekly monitor several factors related to microcystin concentration and do a lab test when those factors indicate likely microcystin growth. This week’s monitoring shows that our lake water quality has improved even further since mid-June.
Harmful algal blooms (HABs) are an excessive growth of cyanobacteria that are capable of producing toxins harmful to human health. Ohio EPA guidelines call for two levels of warnings: “Recreational Health Advisory” with microcystin concentrations of 6-20 ppb, and “Recreational No Contact Advisory” with concentrations greater than 20 ppb. If a “Recreational Health Advisory” is issued, swimming and wading are not recommended for children, pregnant or nursing women, and those with certain medical conditions. With a “Recreational No Contact Advisory,” all are to avoid contact with the water.
During the past three years, we’ve implemented an aggressive program to combat our microcystin worries. We’ve treated the lake with copper sulfate when our weekly lake water monitoring results caused concern. We’ve dredged phosphorus enriched sediment. Also, we’ve eliminated geese and installed aerators.
Individual home owners have done their part too. They have used phosphorus free lawn fertilizer, harassed geese so that they seek other environments, refrained from feeding geese, and kept clippings out of the lake and drainage ditches to prevent additional nutrients making their way into our water. They have adhered to boating rules, both the no wake/idle speed only rule and ‘no plow’ rule, to minimize stirring of bottom sediments rich in phosphorus. On the lake front, they’ve made sure the shoreline is adequately protected to prevent erosion. Construction projects involving bare earth have controlled erosion as well.
Most importantly, there has been less phosphorus moving into the lake from the watershed. Farmers in our watershed have reduced phosphorus fertilizer use and have installed riparian zones, cover crops, and grass filter strips. Some watershed farmers have used financial support from our grant funds to help pay seed costs for cover crops and grass filter strips.
Thanks to those who contributed to our improved water quality. During the upcoming holiday weekend, all can enjoy a splash in our lake that’s pretty darn clean.