Salty Lakes

It’s about time this effect was well documented see: Center for Limnology Salt Study

What would we expect? Adding a highly soluble, conservative pollutant will runoff into and accumulate in lakes.

This is not new news. My studies of metro lakes in the 1980s also documented this. It got no traction (excuse the pun) as safety trumped contaminating lakes (and streams and groundwater …).

I published a blog, copied below, called Salt and Mirrors following a plea to use less slat in the Twin Cities several years ago.

[From December 2014]

Salt is bad for our lakes.  Chloride, the offending element in salt, has been accumulating in metro lakes for the past half century, corresponding to the use of de-icing road salt.  This is an insidious kind of pollution because its impacts are gradual.  Yet, increases in chlorides affects the entire lake food chain, favors undesirable, even toxic, algae species and gives aquatic invasive species an additional edge over native species.

So, when public agencies and other environmental organizations call for individuals to use less salt on our sidewalks and driveways, that is good, right?

Of course it is.

But we are looking at this the wrong way.  If we want to stop the increasing chloride pollution to our lakes, moderating individuals’ salty behavior will not accomplish this.

Metro road salt use is 700 million pounds per season.  Seventy percent – 70% – of this ends up in our water.  This is the elephant in the room and until we recognize this, urging changes in individuals’ behavior deflects the issue.

The real issue is we have made a choice – dry winter roads in exchange for polluting our lakes.  Our transportation agencies are on a mission to reduce deicing salt use, but using less just means we are polluting our lakes more slowly.

A main theme in A Lake Manager’s Notebook (discontinued), is our lack of attention to quantifiable objectives.  Agencies’ salt reduction goals are stated in terms of less, but not in terms of exactly how much less.  Lacking specific targets, how do we know if our lakes are really being protected?

Our lake management institutions have adopted a self-empowerment ethic for protecting our lakes.  In this context, I often see reference to the old Pogo cartoon with the caption, “We have met the enemy and he is us.”  This makes me cringe because it implies individuals (us) are the enemy of lakes while at the same time distancing our institutions from addressing the underlying systemic problems.

Chloride pollution to lakes (also groundwater, wetlands, rivers and streams) is a bona fide, pervasive problem and its overwhelming source is road salt.  Mitigating road salt use will not be easy, because convenient, cheap alternatives do not exist.  However, deflecting the onus to citizens and away from agencies is wrong-minded.

So what do we do?

I think we need to shift our attitude and approach to something that more realistically recognizes our societal choices so we can live with and best manage their consequences. I don’t see that we will significantly change road salt use any time soon.  Of course, citizens should reduce their use of de-icing salt, mostly because we can.  More importantly however, citizens, through our institutions should address these concerns more comprehensively and as a matter of public policy.  An involved citizenry can make good public policy choices when given accurate information.  I don’t see the benefit of delusion.

Several decades – and no improvement.

Lake County IL – Another example that whatever we have been doing (or perhaps, not doing) is not leading to lake improvement. This story provides examples of attempts to mitigate pollution, but no real improvements.

To improve eutrophic or phosphorus-impaired lakes requires substantial, sustained reductions in incoming phosphorus as well as immobilizing internal phosphorus. Almost always, these involve interventions rather than tweaks.

Lake Advocates is knowledgable about applicable technologies.

A different way for MN to achieve its ambitious clean-water goals

In the commentary I explored options to achieve water quality goals referring to “end-of-pipe” solutions. I have received a number of comments and questions about this. In some cases, it was assumed I was referring to treatment on every field or property. To clarify, I was referring to treatment of non point source runoff as collected naturally (by streams) or artificially (ditches, pipes) at points well downstream from the original sources and near discharge points to receiving waters. Some also misunderstood “pipe” to refer to a point source. It actually refers to the end of some collection system receiving runoff (or non point source) pollution.

It was also suggest to let the buffer program work. I am still looking for evidence (based on objective assessments) that buffers will remove nutrients sufficiently to make a substantial difference in MN’s impaired waters.

Phosphorus Inactivation Workshop

Harry Gibbons and Dick Osgood, Lake Advocates founders, are leading a workshop titled, “Lake & Pond Phosphorus Inactivation & Interception.” This is the 14th year we have presented this workshop.

Workshop Description:

Phosphorus management through mitigating excess phosphorus loading to lakes from its watershed may be difficult, expensive and require many years before lake water quality is observed. Inactivation of phosphorus has been one of the most effective lake management tools and may be used to safely, quickly and efficiently eliminate water quality problems. The most effective phosphorus inactivation tool to date is aluminum sulfate (alum), although other precipitants are available and will be discussed. Alum’s use will be presented in the form of planning, design, application, and monitoring. Case studies will be discussed from a lessons learned and potential future use perspective. In addition to discussing partial and whole lake alum applications, alum use to remove phosphorus from the water column, to inactivate sediment phosphorus or intercept phosphorus in stormwater runoff and alum use in ponds; other inactivation and flocculant alternatives approaches will also be presented and discussed. Participants will learn about alum technologies and strategies through published literature overviews, third-party assessments, real-world data, case histories and participant interaction. Topics include internal and external phosphorus sources, alum precipitation chemistry (and other flocculant chemistry), application technologies and strategies, dose determination, phosphorus interception, effectiveness, longevity of phosphorus inactivation, and project examples. Techniques for evaluating the timing and magnitude internal and external phosphorus inputs will be reviewed in the context of designing alum application strategies. Differences between thermally stratified versus unstratified (polymictic) lakes will be discussed relative to application strategy. Regulations and permitting will be also be outlined and discussed. Participants will be encouraged to share their experiences during the workshop. Workshop includes a workshop manual with worksheets and a detailed bibliography.

The day-long workshop is help in association with the North American Lake Management Societies’ annual symposium on Tuesday, November 1st in Banff, Alberta.

For registration information, see: