Can We Start Protecting Jordan Lake Now?

One of my motivations for writing this column is my hope that, at least in some small way, I am helping to inject more science into public policy decisions. Maintaining this hope can be especially challenging at times. The “experiment” to clean up Jordan Lake with larger mixers known as Solar Bees presents one of those challenges. Allow me to walk you through my frustration on this ill-fated and poorly-reasoned project.

As local readers will likely know, Jordan Lake provides drinking water for over 300,000 people including the city of Raleigh. In addition, it provides fishing, boating, and swimming opportunities for thousands of people and a place to live for fish, birds, and a variety of other wildlife. For many years now, Jordan Lake has been consistently failing water quality standards for chlorophyll. Before discussing options to address this problem, let’s review how a lake comes to fail chlorophyll standards and why that is a problem.

Chlorophyll is the molecule that makes plants green and that captures sunlight for photosynthesis. Chlorophyll in lake water comes primarily from algae, so a lake with too much chlorophyll has too much algae, a situation often referred to as an algae bloom. Algae blooms occur when a body of water accumulates high levels of nitrogen and phosphorous containing nutrients. These nutrients enter the watershed from run-off of fertilizers, primarily from residential and commercial rather than agricultural locations⁽¹⁾, and from the outflow of municipal wastewater facilities.⁽²⁾

Excess algae in lakes and other bodies of water can cause several problems. Some species of algae produce chemicals that are toxic to humans. This can cause problems both for swimmers and can also threaten water quality if the lake is used as a drinking water reservoir. Lakes with an algae bloom are aesthetically displeasing and often emit foul odors. Further, excess algae in a lake also lead to reductions in dissolved oxygen concentration, a subject that I expand on below.

Algae tend to live on or near to the surface of lakes where they can receive sufficient sunlight. They have short life spans and fall to the bottom of the lake when they die. Bacteria that live at the bottom particularly enjoy dead algae as food and consume dissolved oxygen in the process of eating it. Thus, a lake with excess algae on the surface rapidly losses dissolved oxygen. If the oxygen concentration drops too low, fish and other aquatic life suffocate and die.

In analogous manner to most any other pollutant, the problem of excess nutrient accumulation is best addressed by reducing the introduction of these nutrients at their sources. It is important to note that this is a scientific rather than a political statement. Pollutants are concentrated at their source and become diluted when allowed to escape. The laws of thermodynamics tell us that the energy one needs to expend to collect and remove a dilute pollutant far exceed that required to manage a concentrated pollutant. Therefore the best and most energy efficient manner to protect Jordan Lake is to make improvements at wastewater treatment plants and to improve regulations for residential and commercial development to limit run off. These approaches would raise the cost of wastewater treatment and real estate development, so it should not surprise you that some people and groups are opposed to making these changes.

Over many years all of Jordan Lake’s stakeholders, developers, citizens, legislators, and the like, negotiated a set of regulations and standards to reduce the flow of nutrients into Jordan Lake’s watershed with the approaches I outlined in the paragraph above. Theses rules set to take effect in 2009, nearly seven years ago. Since then, parties opposed these rules have successfully lobbied for successive delays and the regulations are still not being applied and enforced. The most recent delay was granted to allow this Solar Bee “experiment” to be attempted.

• Solar Bees are large, floating solar-powered mixers . In early 2014, the North Carolina General Assembly approved yet another delay in the implementation of the Jordan Lake rules in order to try to use them to solve the problem instead. The intent of the mixers is to push nutrients entering the lake to lower depths before they can fertilize algae growth near the surface.   In addition, the mixers are supposed to disperse the algae such that the lake looks better. There is such a long list of flaws in this plan that I think I decided to resort to bullet points to detail them.
• Mixing works best in regular, nearly circular geometries. To the extent there are irregularities in the geometry, poorly-mixed pockets inevitably occur. Have a look at this map of Jordan Lake. You can’t get much more irregular than that.   The idea that you could mix up Jordan Lake in some effective fashion without essentially blanketing its surface with mixers requires both a total disregard for engineering principles as well as a healthy measure of hubris. I supposed this point seems a bit nuanced to some, but it really gets under my skin. Legislators can see North Carolina State University and its top-notch engineering school from the rooftop of the General Assembly building. I’m sure they’d be happy to help.
• Even if the Solar Bees worked, nutrients entering the lake would accumulate over time in the sediment on the bottom of the lake.   These nutrients would then bide their time until a storm or flood resuspended them, thereby bringing about the mother of all algae blooms.
• Lastly, even if the mixers worked as their supporters hope, since they are only in the lake, they would only protect the lake. This would allow nutrients to continue to flow into every other stream, river, pond, or marsh in the rest of the watershed allowing for algae to bloom everywhere else.

When the Solar Bee project was being considered in early 2014, I delivered this commentary on 97.9 FM/1360 AM WCHL. Have a listen if you want to get a better sense of my frustration.

Last month a report was issued on the effectiveness of the Solar Bee project after then had been spinning about for a year. As could have been and was predicted, there have been no improvements in water quality in Jordan Lake. This hopeless project should be stopped and the Jordan Lake rules intended to be implemented in 2009 should be put into place as soon as possible.

Sadly, that is not the likely outcome. The Solar Bee project has been given a 4 year time period to demonstrate water quality improvements. This extended timeline is yet another example of how this project is ignoring basic science. There are no aspects of the Solar Bee technology that would take multiple years to take effect. Nevertheless, it appears that we will delay another 3 years before starting to fix this problem. That is a shame.

Jeff Danner discussed this column with Aaron Keck on WCHL.

 

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1. Often when the run off of fertilizers into watersheds is discussed, farms a listed as a key source. While there is certainly some run off of nutrients from farms, farmers usually go to great lengths to minimize this. They are paying for the fertilizer and manage their lands and operations to keep them in place. The over application and misapplication of fertilizer to residential and commercial lawns is a larger contributor to the problem.
2. I am currently serving on the Board of Directors of the Orange Water and Sewer Authority, the utility that provides drinking water and waste water treatment services to the cities of Chapel Hill and Carrboro, North Carolina, the University of North Carolina, and some surrounding areas of Orange County. The outflow of the waster water treatment plant is in the Jordan Lake watershed. As is the case with this and all of my columns, the opinions contained within represent my opinion and are not a statement of the Board.