This week, the Chesapeake Bay Program released its annual Bay Barometer report. Along with the Chesapeake Bay Foundation's annual State of the Bay and the University of Maryland Center for Environmental Science's Chesapeake Bay Report Card, the Bay Program's report closes out the assessments of the Bay for 2016 (for what it's worth, CPR Member Scholar Rena Steinzor and I released our own assessment last year).
The Bay Barometer is chock full of charts describing the progress (and lack thereof) being made toward the many water quality, ecologic, and wildlife outcomes established by states in the Chesapeake Bay Watershed Agreement. While glancing through several of the graphs in the Barometer report, I wondered: Which graphs would I use to convey a sense of progress? What would be my "chart of the year" for 2016?
For me, that chart-of-the-year honor has to go to a series I found in a press release by the U.S. Environmental Protection Agency (EPA) last June. But before I introduce and describe the charts, a bit of background on the subject is in order.
One of the central questions for those who study Bay restoration is, How will the ecosystem respond to the pollution reductions prescribed for the Bay watershed through this "pollution diet"?
Academic, government, and private-sector scientists and engineers have a pretty good grasp of causality or directionality: X –> Y –> Z. If we spend our environmental restoration dollars on technologies and best management practices (X), then we will reduce pollution in the watershed (Y), leading to a healthier ecosystem (Z). But it's that last part – getting from Y to Z, from pollution reduction to ecosystem improvement – that remains a bit of a mystery.
As CPR Member Scholar Robin Kundis Craig described in a recent paper, environmental laws often pose two types of "zero-sum" policies, such as cap-and-trade programs or, in the case of the Chesapeake Bay, total maximum daily loads (TMDLs). These zero-sum policies are effective because they establish a cap or limit representative of the amount of pollution a particular resource or ecosystem can handle, under which all polluters must remain. But Craig notes that these zero-sum policies can be based on either discovered or invented limits. If the limit or cap is invented based on unsound assumptions or incomplete data, the ecosystem response may fail to materialize, at least until scientists discover the true limit.
Here in the Chesapeake Bay, our zero-sum TMDL is based on decades of scientific research from teams of state, federal, and academic scientists. Still, the Bay restoration process under the TMDL represents a cutting-edge, first-in-the-world experiment as an estuary, ecosystem, and habitat restoration project. Considerable uncertainty remains regarding when pollution reductions will finally give way to an estuary clean enough to bring about a return of historic conditions.
All this is why I would nominate for charts of the year a set of time-scale graphs correlating a reduction in pollution following the upgrade of major sewage treatment plants with a rapid improvement in submerged aquatic vegetation ("SAV" or underwater grasses). Few graphics I've come across convey such a profound sense of hope and optimism that what we're doing is working.
SAV is one of the most important metrics used to gauge how well the Bay and its tidal tributaries are doing. These underwater grasses are not only an indicator of cleaner water but also a driver of ecosystem response, as they provide habitat for several critical species. In other words, SAV is both a cause of clean water and an effect of clean water.
And the reason why these charts are so revealing is they draw that clear link described above from an investment to pollution reduction to an ecosystem response – and in a very short period of time. The implication of these charts is also that the dominant strategy to restore the Bay – the widespread investment in advanced wastewater treatment technologies – is working and having a substantial impact. In each chart, the drop in the red line (pollution) corresponds with an almost immediate and significant increase in the green bars (acres of SAV). To view the charts, see this EPA fact sheet.
Unfortunately, the Bay can only ride this tide for so long. A significant number and percentage of large municipal and industrial wastewater facilities have already been upgraded with advanced pollution reduction equipment. With this relatively low-hanging fruit being picked, the states in the Bay watershed and EPA will need to turn their attention to the remaining sources of pollution reduction, many of which will not have the same immediate impact on water quality.
But with so much bad news these days for public health and the environment, at least we can focus on some good news in the Bay region. The message is clear: government investments that rely on science-based policies can and do result in measurable improvements for us and the natural areas we treasure.