Lake Jesup is Florida’s tenth largest lake (10,660 acres). It is a hypereutrophic water body located entirely within Seminole County. The US EPA has identified the lake as impaired for nutrients and un-ionized ammonia. Target concentrations of total phosphorus (TP) and total nitrogen (TN) required by the Total Maximum Daily Load (TMDL) are 0.096 milligrams per liter (mg/L) TP and 1.27 mg/L TN. These represent a 34% and 50% reduction in the respective nutrients from the reference conditions. The FDEP authorized its Basin Management Action Plan (BMAP) to remediate the lake and achieve these levels in May 2010. On September 4, 2015, at the Seminole County Extension Auditorium, the Florida Department of Environmental Protection (FDEP) presented its 2015 Annual Progress Report for the Lake Jesup Basin Management Action Plan to summarize the work to date. Click here to download a copy of the report.
The meeting was administered by the FDEP’s Watershed Planning and Coordination Section for the Lake Jesup Basin Working Group, and open to the public. Meeting topics included a review of the annual report and a summary of Lake Jesup’s overall condition. A slideshow on upcoming TMDL model revisions was given, and the meeting was opened to the floor for discussion.
The Lake Jesup BMAP is a regulatory document. It was created by regional stakeholders and commits projects and other resources to meet the Lake’s TMDL over three, five-year incremental periods. The BMAP assumes that by removing 18,749 pounds of TP year after year, the lake will return to its intended use classification and no longer be considered impaired. The tables in Appendix A of the progress report show that, during the first five-year BMAP phase, 15 stakeholders created or planned 214 nutrient reduction projects. The total projected TP removal from all projects listed is 15,433 lbs of TP per year. The completed projects are shown to be removing 14,073 lbs of TP per year.
The presentation and 2015 progress report indicates that TP and Total Suspended Solids (TSS) concentrations trended downward in the lake and its tributaries between 2009 and 2014. However, according to the last (2014) progress report, there is no significant long-term TP trend. There is no mention of TN concentration trends in this update, but TN allocations are planned for the BMAP’s second iteration due in May 2016, so stakeholders will be required to create new projects to reduce and monitor it.
The 2015 progress report goes on to say that, “No major changes have been observed in chlorophyll a concentrations in the lake during the period of observation (1995-2014),” and that, “Chlorophyll a concentrations above 40 milligrams per cubic meter have been observed more than 50% of the time between 1995 and 2014, indicating there is an algal bloom problem in the lake.” What this means is that, although a short-term trend in TP reduction is observed, those concentrations are still above the TMDL, and the lake has not responded biologically yet.
The State is counting on the science that says if you reduce TP in a system limited by phosphorus, then the nitrogen and algal concentrations will fall in line by themselves. Recent evidence says this may not always hold true. When the nitrogen-phosphorus ratio is manipulated, the algal populations will shift. If nitrogen is not reduced along with phosphorus, then algal blooms may continue with species that can adapt genetically, or with different species that are tolerant of the new conditions. Not only is nitrogen reduction important for ratio purposes, but the adjacent BMAP for Lake Harney and Monroe calls for a 275,000-pound TN reduction from Lake Jesup. Both of these factors contribute to the addition of TN allocations in the 2016 BMAP iteration, and start of the second, five-year Lake Jesup BMAP phase.
As with any detailed data analysis, the numbers are easy to confuse. Reviewing the progress report’s project tables in Appendix A shows there are many projects from which direct measurements can be taken. However, over two-thirds of the TP reductions claimed are estimates derived from indirect measurements. For instance, stakeholders are given TP reduction credit for sweeping streets, creating public education campaigns, and estimating the nutrient reduction from existing storm water systems designed using the State’s narrative criteria (i.e., existing BMPs).
Street sweeping credits are calculated based on the pounds of material collected, not what is in the material. Public education benefits rely on the people to change their habits with no real way to measure the effects. Storm water systems designed using the State’s narrative criteria are well known to underperform, and so calculating credit from one of these systems that may or may not have been maintained properly is difficult without direct measurements. These programs do influence nutrient load reduction and should be continued, but the stakeholders are claiming 10,759 pounds of TP credit (or 69% of the total reduction claimed) from them alone. Nobody knows how much TP is really being reduced, and if the lake does not respond, additional projects and expenditure may be required.
The TMDL and first BMAP iteration did not account for all the lake’s various nutrient input sources, only those that could be attributed to an anthropogenic source directly. Nutrient sources whose origin was difficult to determine (e.g., legacy muck, groundwater, etc.) were identified for later study and allocation. These inputs, in preliminary reports, have shown to be significant, and could approach levels seen in the surface runoff. The second BMAP iteration due in 2016 will allocate these loads to the same group of stakeholders. From a review of the preliminary model runs, the total allocations will likely increase overall. Identifying who is responsible for what portion of the reduction will be the tricky part.
The TMDL and first BMAP iteration used the best available model at the time to calculate the loadings and allocations. According to the presentation, this model had a shortcoming in that it did not factor attenuation into the calculations. If a pound of phosphorus was released miles from the lake, the model assumed the entire pound was deposited. In reality, the final amount of phosphorus reaching the water body is attenuated or magnified depending on the conditions between the source and sink. The new model due to be rolled out during the second BMAP iteration in 2016 will include an adjustment for attenuation, and also estimates for groundwater and legacy sediment loading.
Out of the 214 projects in total shown in Appendix A of the 2015 progress report, all reported nutrient reductions. However, only 103 reported project capital costs, and only 31 reported annual operation and maintenance (O&M) costs. Six stakeholders did not report any project or O&M costs, and two others omitted just O&M costs. Total public capital costs reported by those 103 projects are $52,197,727.00. The total annual O&M reported is $2,591,937.00. There is no standard project costing method used, so there is no real way to determine if all the project costs have been reported, but if less than half the projects cost that much, the total bill is likely much higher.
Stakeholders have invested significant public resources into reducing Lake Jesup’s nutrient concentrations using the FDEP’s BMAP as a guide, but according to this latest update, the lake is still experiencing the effects of nutrient enrichment. The projects conducted to date have had a positive effect, and cannot be argued against in terms of doing the right thing. However, they have been done in silos. Each stakeholder has created individual projects that are expensive when looked at on a per pound basis. There are no large, regional projects that could do the heavy lifting cheaply and benefit the entire region.
Since the original allocations were based on incomplete data and modeling, the lake has not been receiving the level of treatment required for the last five years because it turns out that the amount of TP removal necessary to meet the TMDL is more than estimated in 2006 when the TMDL was created. In addition, the projects promulgated to reduce nutrients are mostly “low hanging fruit” such as street sweeping, education, and credit for existing storm water systems whose nutrient reduction potential is dubious at times. Not only is the total cost of nutrient reduction likely to increase because the total allocation is likely increase, but the cost per pound of TP reduction (and moreover TN) without these readily available, inexpensive and credit-rich projects that require little infrastructure will also go up.
The BMAP and its updates are a meaningful start to remediating Lake Jesup. The second BMAP iteration due in 2016 will attempt to address current shortfalls. The addition of nitrogen allocations and the new groundwater and in-lake sources will lead to additional efforts and costs to remediate. Political will and sound science are needed to make sure the issues are addressed, and that nutrient reduction can be verified as having the desired lake effect. Future public expenditures for impaired waters should focus on large, regional projects that maximize removal efficiency and cost (for both TP and TN) instead of small piecemeal projects isolated within political boundaries that are expensive on a per-pound basis or are hard to measure, and have little verifiable effect on the lake’s condition. The water quality credit trading market set to kick off in Florida later in 2015 will help achieve this.
The next Lake Jesup Basin Working Group meeting will be in late December 2015 or early 2016 to review the new model runs and prepare for the second BMAP iteration due in May.