SolarBees have mixed effect on water quality at Blue Lake

By Matthew Preusch, The Oregonian

May 14, 2010, 7:33PM

Water clarity has improved at Blue Lake three years after Metro spent tens of thousands of dollars on algae-combating machines, but the devices may be abetting the spread of troublesome weeds.

“What we’ve found is that the pH has been a little bit worse, the water clarity has been a little bit better, and the toxic-algae problem has been about the same,” said Metro biologist Elaine Stewart.

The regional government and the solar-powered devices’ manufacturer say, however, that it’s still too early to render a verdict on whether the money was well spent.

Matthew Preusch/The OregonianIn 2007, Metro and homeowners on Blue Lake invested in three SolarBee water mixers to try to combat blooms of blue-green algae at the lake east of Portland. The solar-powered machines churn the lake water to limit algae growth.

Metro manages the popular 130-acre park on the lake’s north shore and cooperates with homeowners on the south shore over lake regulations. It split the $150,000 cost for the three SolarBee water circulation devices with the homeowners

Metro Assessment of Solarbee Performance on Blue Lake

In October 2009, Metro released the 2009 Blue Lake Water Quality Summary Report researched and authored by Whitney Temple.  The report provided a review of the two-year trial of three Solarbees placed on Blue Lake and an assessment of the third year that followed the purchase of the units.  Elaine Stewart, Senior Natural Resources Scientist for Metro shared the report with NoSolarBees and elaborated that the report is “neither peer reviewed nor conclusive”.  She continued that she thought, “it points out the complexities of lake systems and the remedies we implement.”

Download the entire report.

SolarBee Assessment of Trial on Blue Lake

In March 2009, Joe Eilers of SolarBee released An Assessment of Circulation Technology Applied to Blue Lake, Oregon.  The report was the conclusion of a two-year trial of three Solarbees placed on Blue Lake.  Purchase of the three units was contingent on the success of the trial as access by Solarbee, Inc.  The report concluded that the units improved water quality and based on the report Metro and the local residents purchased the three Solarbees installed for the trial.

Download the entire report.

For a more detailed summary of the trial and the specific conclusion read on.

SolarBee Study Shows Circulation Suppresses HABs

A new report has been published which suggested that current studies demonstrate that solar powered circulation of the top-most layer in a thermally stratified lake strongly suppressed freshwater harmful algal blooms (FHAB’s) even in nutrient-rich waters. The report states that the mechanism(s) through which solar powered circulation suppressed FHABs remains unknown, the evidence indicated that the magnitude of suppression increased over time. The study was authored by H. Kenneth Hudnell, Head Scientist for Solarbee and reviewed by Joseph Eilers also of Solarbee, Christopher Jones, Bo Labisi, Vic Lucero, Dennis R. Hill; each employees of the three SolarBee installations reviewed in the report.

Download the entire report.

The official press release announcing the study read as follows;

Cynobacteria Report Indecisive on Circulators

Cyanobacterial Harmful Algal Blooms: State of the Science and Research Needs by H. Kenneth Hudnell is a 950 page reference which represents a holistic assessment of the state of the science identifying research needed to address the increasing risks posed by freshwater harmful algal bloom to human health and ecosystem sustainability.  The book contains an overview of the Interagency, International Symposium on Cyanobacterial Harmful Algal Blooms. The symposium contained a section on watershed management techniques designed to reduce Cyanobacterial Harmful Algal Blooms (CHABs) which discussed the use of water circulation systems such as SolarBees.  The report indicated that “research is needed to further assess the effectiveness of bubble and pump vertical mixing systems at controlling CHABs, and to identify the mode(s) of action by which vertical mixing inhibits CHABs.”

Excerpt from report:

Evaluation of the Effectiveness of SolarBees

The Vermont Agency of Natural Resources, in cooperation with the St. Albans Area Watershed Association, conducted a study of the effectiveness of SolarBee (TM) water circulators in reducing algae blooms at the northern end of St. Albans Bay, Lake Champlain during 2007. The study found no evidence that the SolarBees reduced algal concentrations, improved water clarity, or inhibited blue-green algae in St. Albans Bay. The treatment goal of producing an approximately 100-acre zone of clear, low-algae water at the northern end of St. Albans Bay was not achieved by the SolarBee deployment. A report on the study is available at: VANR Solar Bee Report Final.