User:Natureab30/Falling Creek Reservoir Ecology

History and Details

Falling Creek Reservoir as right now is not well studied but can be an important lake to understand for many scientific reasons. Falling Creek Reservoir is located in Vinton, Virginia; even though Falling Creek Reservoir is not as big as other lakes, every lake has a purpose and history to it.Falling Creek Reservoir was constructed in the 1890s. The water resource was used in the city of Roanoke for fire hydrants, troughs for horses, and drinking water for citizens in 1897 after it was granted to Vinton-Roanoke Water Company. Interestingly one of the drinking fountains, specifically the Dog Mountain Fountain, is still used today in Roanoke City Market. Further years Western Virginia-Roanoke Water Works Company became part of it also. In 2010 Falling Creek Reservoir was rehabilitated. The surface area is 0.12 km² with the maximum depth of 9.3m .This reservoir holds around 322 ML of water when completely full and covers 8.5 hectares. A recent study in 2017 involving associate professor Cayelan Carey, Department of Biological Sciences, at Virginia Tech explains the relationship between organic carbon and oxygen by experimenting Falling Creek Reservoir. Cayelan Carey is one of the few researchers who studies Falling Creek Reservoir with her team and received a one million grant from National Science Foundation. The purpose of the grant was to do a real-time water forecasting system for the reservoir to give predictions of the freshwater. With the help Cayelan and her team's data, they figure out ways to produce the best quality of water for their local consumers. Not only is this benefiting the science community by learning the chemistry, physics and biological aspects in smaller water ecosystem but also in social science aspect to help out and communicate with the community, looking ahead of the future. This particular project name is called the smart reservoir project.

Research

Even though Falling Creek Reservoir is a small warm monomictic system, the reservoir provides drinking water for local residents. Also, it is considered a new research site within Global Lake Ecological Observatory Network (GLEON network). The reservoir has two installed systems in the water column that are engineered to manipulate both oxygen concentrations and stratification. Owners and operators for Falling Creek Reservoir, Western Virginia Water Authority (WVWA) have noticed an increase in Cyanobacteria blooms, causing the taste and odor problems. Specifically, Cyanobacteria, sometimes known as blue green algae, are diverse groups of prokaryotic bacteria. Understanding them is important because they're a risk to humans and animals because they produce toxins that cause skin allergic reactions and stomach disturbances. A recent paper with Rousso (2020) says that Cyanobacteria can potentially reduce biodiversity and discoloration to freshwater ecosystems. Installing systems as surface mixers helps control the growth of cyanobacteria which are one of the main organism problems in reservoirs. Mixing systems for reservoirs benefits because limits lighting on cyanobacteria because increased depth of mixing. There is also alternate by adding specific chemicals to control the cyanobacteria but that approach isn't safe for freshwater ecosystems. Positive results showed in McClure et al. (2021) that solar-powered water mixer showed impacts in controlling Cyanobacteria in FCR.

Due to the history of low quality and odor problem of Falling Creek Reservoir, WVWA requested Solar Bee, Inc installed a “solar-powered, up-flow long-distance circulator” and this particular unit runs 24 hours a day and rated 10,000 gallons per min. Parts of the design withdraws water and hypolimnetic oxygenation for the control of cyanobacteria. In 2012, the installed hypolimnetic oxygenation system was used to increase oxygen concentrations without altering the temperature or thermal stratification of the reservoir. However in one of Carey (2018) studies, the crew and her studied the organic carbon (OC) cycling and activated and deactivated the hypolimnetic oxygenation system (HOx system) during the 2014 summer stratified season. Specifically from June to October and from there they were abled to monitor 3 times a week the organic carbon concentrations, oxygen concentrations, thermal structure, and water budget .Although FCR is small, FCR shows a stable thermal stratification, usually from May to early October, forming a clear and discrete hypolimnion suitable for oxygenation. The importance of this study is oxygen availability near sediments is important for mineralization of OC in freshwaters and depend on oxygen because it will determine whether OC inputs are buried or respired. An unique formula used to see the changes of OC over time of the study was "dOC/dt=Allochthony+Autochthony–Respiration–Burial–Export". All external sources of OC, including aerial inputs and surface inflow was the Allochthony, Net primary production within the reservoir was Autochthony, all mineralization of OC to inorganic C was Respiration, long-term burial in sediments was Burial , and export via surface outflow was Export. Through their study scenarios with the oxygen concentrations, the study suggested that the hypolimnion's oxygen concentrations responded rapidly to activation and deactivation of the HOx system. When the HOx was activated, hypolimnion's oxygen concentrations increased above 5 mg L-1, meaning also well mixed.The lower hypolimnion experienced a greater degree of dissolved oxygen depletion than the upper hypolimnion without oxygenation, resulting in metalimnetic oxygen depletion when HOx system was turned OFF 1 during the experiment. Interestingly oxygen concentrations at the sediments took longer to increase to 5 mg L-1 during ON2 than ON1, the study suggested because of the hypolimnion exhibited anoxia before ON2, as opposed to hypoxia before ON1. OC burial in FCR is more affected by oxygen concentration than oxygen duration, according to the modeling scenarios approach. Therefore, the study mentions lakes and reservoirs are increasing hypolimnetic anoxia because of climate change, land use and human factors. However, a significant increase in oxygen at the sediments can lead to a significant increase in respiration rates, quickly undoing any gains in burial gained during anoxia and possibly turning the water body from an OC sink to a source of OC.

2014 successful report involving Gerling et al. (2015) and other scientists preach about the importances an oxygenated environment in the hypolimnion to prevent the release of nutrients and reduced metals - such as phosphorus (P), iron (Fe), and manganese (Mn). The benefits of maintaining and reducing metals is better water quality because algae growth increase with phosphorus and bad taste, color and odor are caused by iron and manganese. Therefore, these causes won't be good for drinking purposes. With Carey recent successful study with HOx system, this study also says the advantages of a HOx system compared to hypolimnetic aeration systems because of higher oxygen solubility, and higher oxygen transfer efficiencies. The SSS system (or HOx system) installed September 2012 in the FCR consists of six main components: submersible pump, oxygen source, oxygen contact chamber, distribution header and inlet and outlet piping. As Carey study, they wanted to see the FCR differences of temperature, dissolved oxygen, and concentrations of metals when the system was deactivated and activated. Results showed that the SSS system significant effect on increasing hypolimnetic dissolved oxygen concentrations, however for further studies they recommend to keep SSS system to stay consistent. Beutel article speaks about the advantages of hypolimnetic oxygenation because of pure oxygen and efficiency but it also one newest approaches for to prevent hypolimnetic aeration. First know recorded of hypolinetic oxygenation was a stream pumping system used located in Ottoville Quarry, Ohio during the summers 1973-1974. Both years showed maintained thermal stratification. Other forecasting experiments in FCR mentions the importances also understanding methane and how it plays its role in biogeochemical flux.