The controversial solar devices used for the past two years in an effort to control weeds on Monona Bay won’t be returning next year. “There just wasn’t any evidence the SolarBees were doing anything for us,” said Genesis Bichanich, a water resource specialist with the city of Madison’s engineering department.
The city first used the floating water circulators in a free trial in 2005, but data on their effectiveness was inconclusive, Bichanich said. This year, the city rented the devices for about $75,000, and could have applied 60 percent of the rental fee to the $225,000 cost of purchasing them.
Five SolarBees were placed in Monona Bay, and a sixth one was positioned in a triangle formed by the railroad trestle and bridge over John Nolen Drive.
The 16-foot-wide, solar-powered machines — which suck water from the bottom of the lake up through a tube and distribute it on the surface over an area of up to 50 acres — were designed to attack blue-green algae by circulating water and disrupting the habitat.
Some residents around the bay were optimistic the SolarBees could help eliminate smelly, and sometimes toxic, blue-green algae blooms, as well as reduce weeds and improve water clarity.
But the state Department of Natural Resources and UW-Madison faculty warned they could actually create algae blooms by stirring up nutrients in the water.
Jeff Swiggum, a member of Friends of Monona Bay who lives off of the bay on Lakeside Street and walks by it each day on his way to work, said he was “rather ambivalent” about the SolarBees.
“There was no real good data prior to their placement,” Swiggum said. “There were a lot of weeds out there this year. Could there have been more had we not had SolarBees? We don’t know.”
Swiggum said he’s not upset to see them go.
“There may be some people who look at the SolarBees as finally, the city is doing something. It may be more symbolic. … On the other hand, there were a lot of people who felt they were a big waste of money,” he said, adding that some residents saw the devices as “big ugly thing collecting bird feces.”
“Maybe having weeds in the bay is not such a bad idea,” Swiggum said. “Without weeds, it can just become an algal cesspool.”
To view the companies response select
The response provided from SolarBee, Inc.
In the spring of 2005, the City of Madison (City) initiated a collaboration with SolarBee, Inc. (then a division of Pump Systems, Inc.), to address Monona Bay’s long history of blue-green algae blooms. This 160-acre bay receives the stormwater runoff from Madison. With a maximum depth of about 13 feet, this bay also has a nearly 100% coverage of the submersed aquatic weed Eurasian watermilfoil (EWM). The testing occurred in the summers of 2005 and 2006, with the units removed during the fall/winter/spring of 2005-06. The written, agreed-upon goals of the test were to: 1) improve the fishery, 2) eliminate blue-green algae blooms, which are a main cause of periodic anoxia, 3) improve the pH, chlorophyll a, water clarity, and eliminate odors, and 4) slowly reduce invasive aquatic weeds. Unfortunately, due to permitting delays the units were not installed until late May in both years, and long after the EWM had already reached considerable height in the water column.
Nevertheless, we consider the results at Monona Bay to be as positive as could be reasonably expected under the specific circumstances of this test. Considering the constraints of: 1) seasonallylate deployments in a basin already heavily infested with invasive weeds, and 2) the non-optimal depth of intake hoses (because of unfounded concerns of sediment resuspension), we believe that the lack of harmful algal blooms and associated beach closures, lack of odors, good water clarity, and good dissolved oxygen concentrations/profiles during the summer months of both 2005 and 2006 were clear positives.
However, prior to 2005 there had not been any scientific studies or systematic water quality data collected on Monona Bay, and a few people within Madison’s academic/scientific community were adamant from the beginning that several years of pre-SolarBee data were needed for a scientifically valid evaluation, and were equally adamant against the SolarBee deployments in Monona Bay. In balancing the inconclusiveness of the data, the persistent negativity from a few local scientists, and fiscal concerns, the City decided to terminate the test in the fall of 2006 even though a number of local residents believe that Monona Bay had its best, odor-free water quality in memory during the 2005 and 2006 test years. The City has always been supportive and a pleasure to work with, and appreciating the myriad of factors that can go into decisions to spend public funds, we fully respect their decision and continue to maintain a good relationship with the City.