Conservation Minnesota

Choosing Lake Management Tools or Pixie Dust

Lake managers have many techniques and technologies available to choose from.  More and more, lake managers and our clients confrontDick-Osgood-bio situations where newer techniques and technologies make unsubstantiated or unrealistic claims of efficacy, scientific basis, safety or lack verifiable field demonstrations.  Too many times these lake management techniques and technologies that have fallen short.

Lake managers and the profession of lake management have been lax by employing activities or products that do not perform nor enable attainment of lake management goals.

How do you know what will work (or not)?

How Did We Get to this Point?

In the 1970s and 1980s, the federal government funded research and demonstration projects that resulted in a systematic understanding of lake problems, modeling analysis and effective (or not) lake management techniques.  However, in the last 20 years or so, federal (and most other governmental) funding and research support has been greatly reduced and the development or refinement of lake management techniques and technologies has shifted largely to private interests or not at all.  This lack of independent, objective validation has engendered an increase in quick, easy, cheap, natural, non-chemical, risk-free, do-it-yourself and miracle cures.  The availability of these seemingly attractive alternatives has created a distaste and distrust for bona fide techniques and technologies.

The upshot is there are many untested, unreliable tools and technologies out there.  Here, I offer guidance for evaluating available lake management tools.

Look at these marketing claims that claim to work, at least for selling medical products:

-Eats fat

-Liver Aid – cleanses your liver

-Eliminates wrinkles

-Turns fat to muscle

-Patented formulations

-Safe, natural, effective

Who among us abandons medical science for remedies making these claims?

However, in lake management, we encounter a strikingly similar list:

-Eats muck

-Lake aid – cleanses your lake

-Eliminates weeds

-Turns nutrients into fish

-Patented formulations

-Safe, natural, effective

And, many of these are “less expensive” and “natural” too.

I have heard these remedies referred to as “pixie dust,” which according to Walt Disney “can help humans fly if they think happy thoughts.”  But we ought to approach managing lakes with more than happy thoughts.

In the lake management profession, we are exposed to muck reducers, patented formulations, bacteria concoctions, enzymes, aeration/oxygenation/mixing machines, artificial islands and numerous techniques claiming to simultaneously make clear water, bigger fish, eliminate weeds, algae, muck & odors.  Many of these lack any objective, systematic assessment.  Many people, organizations and agencies buy this stuff because they are perceived to be less expensive, environmentally safe, and more effective than long-term integrated approaches.

How can (and should) lake management technologies and approaches be evaluated to assure the lakes we are entrusted to manage are best served?

Evaluating Lake Management Techniques

Standards Used

The gold standard for a science-based profession such as lake management is the peer-reviewed journal.  Scientific journals are peer-reviewed, meaning their editors seek anonymous scientists/peers to review and recommend acceptance (or not) of each manuscript to assure the highest level of scientific scrutiny and standards.

What makes a peer-reviewed article meet a higher standard?  Peer-reviewed or scientific journal articles must adhere to a strict format that includes detailed methodology, adherence to the scientific method (testing hypothesis, using controls, being repeatable), reporting of all results (positive or negative), discussion of the relevance and import of the results in the context applicable literature and operational guidance.  These articles are reviewed by qualified neutral peers and accepted with their consensus.  This procedure assures scientific rigor and dispassionate objectivity.

When available, I (and most of my colleagues), give deference to peer-reviewed sources when evaluating the efficacy and reliability of lake management techniques.  Guidance provided by peer-reviewed sources should trump other sources.

However, just because a technique is covered in a peer-reviewed journal, does not mean it is appropriate in every case.  Pay attention to:

-What the results actually tell you.  There are some cases where the results indicate the technique is not effective.  For example, I am aware of only one peer-reviewed journal source for the use of weevils to control Eurasian watermilfoil on an operational basis and the results were equivocal and the authors recommended further study.

 -A technique may be effective in some cases but not in others.  Make sure you understand whether your lake’s situation calls for a particular technique.  For example, artificial circulation (sometimes called aeration) is a valuable technique in some cases, but it may be useless (or even harmful) in many other cases.  Artificial circulation requires detailed diagnostic studies, appropriate engineering and sizing analysis and ongoing monitoring and evaluation.  Lacking these critical steps, artificial circulation usually will not work.

 -Be careful about “cherry picking” your sources.  Many techniques have peer-reviewed articles spanning a long period of time or a wide range of situations.  Before selecting (or eliminating) a technique, conduct a thorough and comprehensive evaluation of all available literature.

Many newer technologies, tools and approaches do not yet have an adequate peer-reviewed literature record.  In these cases, extreme care must be exercised.

For example, there is almost no peer-reviewed literature on these popular management techniques’ efficacy:

-Bacterial/microbial/enzyme products

-Bubbler/circulation units and arrays

-Floating islands

-Rain gardens

-Most biocontrols

I often hear proponents say, they have not had time to publish their results or try to distract potential clients by offering hand picked testimonials.  I recommend steering clear of these – if it sounds too good to be true …

Gray literature – agency reports, professional society magazines, professional meeting presentations, graduate dissertations, consultant reports, etc. – may be useful; however, greater care is required in sorting through the often contradictory or incomplete guidance provided by these sources.  In addition, these sources tend to lack the scientific rigor of peer-reviewed literature.

The standard I use for evaluating, recommending and implementing lake management methods and techniques requires demonstrated efficacy (using physical measurements) involving an independent investigator.

Sources not meeting an acceptable standard (at least for me) include:

-Self-reporting by those who recommend a technique or approach.

-Self-reporting by manufacturers, vendors or applicators.

-Anecdotal accounts, testimonials and those involving no physical measurements or recorded observations.

Many newer techniques, those I referred to as “pixie dust,” may turn out to be beneficial in some cases, but for now we just do not know with a reasonable level of assurance.  Those selecting these techniques fall into a “buyer beware” category.

In the end, we all want to improve our lakes using effective and safe tools and technologies.  In most cases, there are several feasible options with both positive and negative attributes.  In all cases, I recommend having clear and measurable expectations and objectives, use techniques with demonstrable efficacy and reliability and always have an independent third party monitor the outcomes.

About Dick Osgood

Dick Osgood
Dick Osgood has authored numerous scientific journal papers, made hundreds of presentations at professional meetings, and recently co-authored his first book.  Now he’s working on his second book titled A Lake Manager’s Notebook.  Dick is a Certified Lake Manager and offers lake management consulting services through his business Osgood Consulting LLC.
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