Update Provided By:
Bill Fazier (NCBFN Conservation Director)
H Kenneth Hudnell, PhD, VP & Dir. of Science
New Bern, NC
GridBee® / SolarBee®
The need for water body treatments in impaired reservoirs is explained in the below 750 word paper. Installing SolarBees in Jordan Lake is only the first step in developing and implementing an Adaptive Systems Approach to Freshwater Management – complementing cost-effective watershed management Best Management Practices with cost effective water body management technologies to finally enable a large, impaired water body to attain water quality standards. An Adaptive Systems Approach to Freshwater Management and other water body management technologies are further described in recent EPA webinar slides – http://www2.epa.gov/nutrient-policy-data/epa-webinar-prevention-control-and-mitigation-cyanohabs-presentations
Saving Jordan – Improving Freshwater Reservoir Management
Safe drinking water and clean recreational waters are essential for North Carolina’s growth and prosperity. Much of our state derives these services from reservoirs such as 14,000-acre Jordan Lake. However, reservoirs are artificial waterbodies constructed to control water quantity, not quality. Built on low-lying, nutrient-rich farmlands, and filled with water that can take more than a year to traverse the lake, Jordan has always been impaired. Jordan is eutrophic, having high nutrient levels and quiescent, stagnant water that enable detrimental blue-green algae (cyanobacteria) to predominate the beneficial algae at the base of the aquatic food web.
Cyanobacterial “blooms” cause high chlorophyll-a, pH, and turbidity levels, Jordan’s “official” impairments. These surrogates indicate the potential for serious effects on health and the sustainability of aquatic ecosystems. Some cyanobacteria produce bad-taste and odor compounds, and toxins that can kill or cause illnesses. “Blooms” stress aquatic processes, reduce biodiversity, and deplete dissolved oxygen during die-offs, causing fish kills. Luckily, little toxin and few fish-kills have been observed in Jordan so far, but increasing temperatures further favor cyanobacteria. To avoid realizing the potential, we must improve Jordan’s water quality.
Developing a cost-effective plan to improve Jordan’s water quality requires addressing these questions: 1) what is federal policy; 2) is it working well; 3) if not, why not, and; 4) how can we do better?
Federal freshwater policy requires implementing the Clean Water Act’s watershed management programs. The point-source (pipes) and nonpoint-source (runoff) programs reduce the input of new pollutants such as phosphorus that promotes “blooms.” Current policy does not require implementing the CWA’s waterbody management (Clean Lakes) program to improve water quality through in-reservoir treatments. The Environmental Protection Agency (EPA) deemphasized waterbody treatments to focus on watershed management without scientific and economic justification. Current policy prescribes “preventive medicine,” but not “supportive therapy.”
Nationally, 64% of lake and reservoir acres are impaired, and only 7.9% of ~55,000 freshwaters listed as impaired prior to 2003 are restored, mainly small, point-source dominated waters. And the problem is increasing. Whereas EPA estimated in 1972 that 10-20% of lakes and reservoirs were eutrophic, the Agency now estimates that ~50% are eutrophic. EPA river-and-stream data indicate those with excessive phosphorus increased from 47-66% between 2004-2008/9. No eutrophic waterbody of at least 1,000 acres in size and 90% of nutrient input from runoff has ever attained water quality standards. Jordan and other large, impaired waterbodies will stay impaired as long as policy partially implements the CWA – watershed management only.
Current “preventive medicine” policy fails because it lacks a sound scientific and economic basis. Point-source pollutant inputs are now only 5-10% of total inputs nationally, but nonpoint-source inputs are increasing. Nonpoint-source “best management practices” are difficult and expensive to implement over large areas, and many are only marginally effective. The Jordan Lake watershed is ~1,700 square miles, 77 times larger than the lake itself. Jordan’s nutrient strategy rules recently suspended by the NC General Assembly are designed to reduce new phosphorus inputs by only 5% at a cost-estimate of $2B. The rules do not address nutrient inputs from groundwater or atmospheric deposition, or the huge internal-nutrient load that will cycle between sediment and the water column stimulating “blooms” for decades. No scientific assessment indicates that implementing the rules will restore Jordan. Current policy is not based on cost-benefit analyses, and accountability is lacking.
Current policy also does not address the second factor that promotes cyanobacterial predominance, quiescent, stagnant water. Scientific literature and over 300 U.S. lake applications indicate that artificial circulation suppresses cyanobacteria and stimulates beneficial algae, channeling nutrients up the trophic levels of the food web. Circulation also helps oxidize some pollutants, prevent mercury methylation, deactivate pathogens, and synergize other technologies that remove nutrients and degrade toxic substances in lakes and inlets where they are more accessible and concentrated. Like human bodies, waterbodies require continual circulation and viable biochemical processes to maintain good health.
Cost-effective freshwater management requires an Adaptive Systems Approach (http://www2.epa.gov/nutrient-policy-data/epa-webinar-prevention-control-and-mitigation-cyanohabs-presentations). A systems approach uses scientific and economic analyses to identify the optimal set of components and processes to bring about the functionality required by the system’s users. An optimal strategy for Jordan would combine cost-effective watershed management input controls with waterbody management treatments to form an adaptive system providing a relatively high likelihood of success, short time to restoration, downstream protection, and low cost. Deploying SolarBee© circulators in Jordan is a good first step, but implementation of a full Adaptive Systems Approach is needed. It’s time we complement “preventive medicine” with “supportive therapy” to save reservoirs like Jordan.