Lake Norwood Experiment May be Noticeable

Thu, August 13, 2015 | Lakes and Parks

This Friday, August 14th, Lake Norwood might take on a different hue and if so it might last a few weeks. Bella Vista Village Property Owners Association (BVVPOA), Lake Ecology and Fisheries Management Dept (LEFM), will be conducting an experiment in the lake along with Dr. Thad Scott from University of Arkansas. This is one of the last experiments to be conducted as 5 years of cooperative / contracted research with Dr. Thad Scott, comes to an end in 2015. Dr. Scott was contracted to research nutrient management techniques set forth in the Lake Nutrient Management Plan that Darrell Bowman, Lake Ecology and Fisheries Manager – BVVPOA, created for village lakes. That plan was approved by Arkansas Natural Resources Commission in March 2011.

The experiment is designed to “enable us to see the flow of the currents in the warm, surface water of lake as created by the two “epilimnetic” long distance lake circulators that have been operating in Lake Norwood since 2012″, according to Bowman. Lake water with red dye added will be pumped into the inlet tube underneath the mid-lake circulator, where the tube pulls in lake water at a depth of 12 feet. The dyed lake water will travel up through the machine and out across the surface waters of the lake and over time should spread throughout the entire lake and distribute throughout the warm-water layer of the lake, which is from the surface to about 12 feet deep. Tracking the dye movement over the first day, days, and weeks afterward will allow us to document if and how efficiently, the machine do what they are supposed to do – circulate water throughout the entire surface of the lake down to a depth of 12 feet. 

The dye is called rhodamine and is detectable with a special sensor once it is in dilution in the lake. But until the dye dilutes to a lower concentration, it could be visible to the naked eye in the surface water of the lake for awhile. The dye is bright orange-red in full concentration and will be very visible as it begins to circulate away from the machine it’s injected into.  The sensor used to detect the dye is on loan to Dr. Thad Scott from US Geological Survey (USGS) and Dr. Reed Green with USGS will also aid in the first day tracking of the dye in the lake. Bowman does know for sure if the dye will be detectable to the naked eye once it has spread out in the lake, or if so, for how long.  But the dye is non-toxic and not harmful. Bowman and the others will track the dye as it spreads in the lake until it reaches a stable concentration throughout the lake. This will indicate how efficiently the long distance lake circulators work. 

A similar experiment was conducted in Norwood about this time last year in summer 2014. But at the time the rhodamine red dye was pumped into the inlet hose at the bottom of the lake, seventy-feet deep, for the circulator closest to the dam. That circulator has been used experimentally as an “upwelling” pump to bring nutrient rich lake water up from the cold, bottom water of the lake to add nutrients to the warm surface water. But the cold water carrying the dye plunged back down to the thermocline before it spread throughout the lake, so no one noticed the dye. It was quickly at a concentration and depth that only the sensor could detect it for up to a month afterward. That experiment demonstrated that cold-water moved up from the bottom of the lake, spread through the entire lake into the thermocline and the warm surface layer within one to two weeks. 

These experiments will help LEFM management personnel better understand the data gathered over the past 5 years. This information will then help determine if the SolarBee machines will be purchased for lake management purposes in the future.

Figure 1.  Rhodamine red dye emerging from the SolarBee 10,000 long distance lake circulator after being pumped into the inlet tube of  machine at the lake bottom, seventy-feet deep. August 2014, Lake Norwood. Once diluted to low concentration, the dye was not visible to the naked eye and could only be detected using a special sensor.  

 

This Friday, August 14th, Lake Norwood might take on a different hue and if so it might last a few weeks. Bella Vista Village Property Owners Association (BVVPOA), Lake Ecology and Fisheries Management Dept (LEFM), will be conducting an experiment in the lake along with Dr. Thad Scott from University of Arkansas. This is one of the last experiments to be conducted as 5 years of cooperative / contracted research with Dr. Thad Scott, comes to an end in 2015. Dr. Scott was contracted to research nutrient management techniques set forth in the Lake Nutrient Management Plan that Darrell Bowman, Lake Ecology and Fisheries Manager – BVVPOA, created for village lakes. That plan was approved by Arkansas Natural Resources Commission in March 2011. This Friday, August 14th, Lake Norwood might take on a different hue and if so it might last a few weeks. Bella Vista Village Property Owners Association (BVVPOA), Lake Ecology and Fisheries Management Dept (LEFM), will be conducting an experiment in the lake along with Dr. Thad Scott from University of Arkansas. This is one of the last experiments to be conducted as 5 years of cooperative / contracted research with Dr. Thad Scott, comes to an end in 2015. Dr. Scott was contracted to research nutrient management techniques set forth in the Lake Nutrient Management Plan that Darrell Bowman, Lake Ecology and Fisheries Manager – BVVPOA, created for village lakes. That plan was approved by Arkansas Natural Resources Commission in March 2011.