Recently, the University of Maryland Center for Environmental Science (UMCES) released their annual report card on the health of the Chesapeake Bay. This has long been a go-to resource for the public in understanding how the Bay is doing generally and for those who want to take a deeper dive into the voluminous monitoring data behind the report card.
But this year’s release has garnered significantly more attention in large part due to the headline that the Chesapeake Bay has received its highest-ever grade. This year’s report has also generated some confusion and questions. Common questions we’ve encountered include: why is a 56% score considered to be a C+; how is a C+ the highest grade the Bay has received; and why are so many officials celebrating such a mediocre score, especially if this 56% is only one tick higher than it was two years in 2023 and, astonishingly, 24 years ago in 2002?
It’s easy to be skeptical about this year’s grade with so many questions and because of the dissonance between what the data seem to show about the Bay’s mediocre health and stagnating recovery and the self-congratulatory pronouncements from elected officials. However, it would be misleading to simply dismiss this report card, whatever you think about a C+ grade, a 56% score, or the overall trend lines. So, we set out to dig a little deeper into the wealth of water quality data available for the Chesapeake Bay (something that these officials deserve to be proud of) to see if we could find some results that were a bit more impressive.
To start with, looking within the UMCES interactive EcoHealth feature at the Chesapeake Bay’s overall score for dissolved oxygen - something that is critical for the survival of fish - and also at the pollutants that impact dissolved oxygen levels (nitrogen and phosphorus), we see unmistakably positive trends. In particular, the trend in phosphorus pollution levels in the Bay and tidal areas is encouraging both in the rate of improvement overall and in the breadth of the trends, with only a few Bay tributaries showing flagging progress. It’s worth asking whether the states’ phosphorus management policies are behind this progress. One could certainly find other positive trends on a Baywide basis specific to certain metrics (e.g., aquatic grasses) and across metrics for certain tributaries (e.g., the James River), but it’s easy to get lost in the charts and trend lines on this one site, so it’s best to pair this sort of analysis with other data and studies.
When most people think about what plagues the Chesapeake Bay itself, as opposed to its tributary rivers, they usually think of the so-called “dead zone” - areas with dissolved oxygen levels that get so low during times of year that it suffocates nearly all marine life. So how are we doing in reducing the size of the annually recurring dead zone? As with most things Bay-health related, it’s hard to know just by looking at data or reading press releases. The dead zone’s size can fluctuate widely from year to year, month to month, one part of the Bay to the other, or even based on what you’re measuring (low oxygen areas vs no oxygen areas).
Rather than trying to make sense of it all, we turned to two of the giants of Bay science: Dr. Don Boesch (a member of CLA’s board of advisors) and his former colleague, the recently departed Dr. Walt Boynton. Along with Jon Mueller, a professor of law at the University of Maryland, these scientists recently published a paper that serves as a reinvigorating refresher on the state of Bay restoration.
One of the more interesting and encouraging findings in the paper is that the dead zone has been gradually shrinking at a surprising rate. Instead of being what some scientists considered to be “recalcitrant,” the steadily improving oxygen levels in the Bay’s deep waters appear to be following a different trend line of increasingly rapid improvement after an initially slow ramp-up period (exponential instead of logarithmic in a basic sense). Indeed, adjusting for precipitation levels, the reduction in the size of the low oxygen (“hypoxic”) area of the dead zone has corresponded neatly with the decline in the nutrient pollution concentrations in Bay waters, and the size of the no-oxygen (“anoxic”) area plummeted by 81%! Talk about good news.
The paper shows that there is a strong “coupling” in the mechanics from pollution discharge reductions, to lower water pollution concentrations in surface waters, to dead zone size. The authors also emphasize an important, but underappreciated point, that the mixing of waters between the main stem of the Bay and the tidal tributaries is very strong and exerts a powerful influence on the health of our rivers. The authors thus urge that the water quality is indeed responding as predicted and that we ought to at the very least stay the course, if not double down on our efforts to reduce nutrient pollution to the Chesapeake Bay.
Moving away from the scientific literature and the main stem of the Chesapeake Bay outward toward those rivers and streams, we can also find pockets of good news that are legitimately impressive - deserving of something far better than a C+. For example, the state-federal Chesapeake Bay Program Partnership’s team of scientists has done a great job in recent years of compiling water quality data into useful tools for public consumption. We carefully picked through the data from the nontidal water monitoring network to see where in the 64,000 square mile watershed communities might be seeing particularly strong declines in nutrient and sediment pollution. While the experience was sobering in that overall, fewer than half of the monitoring stations had improving nitrogen concentrations, only a third had improving sediment pollution concentrations, and less than a quarter of stations sadly had improving phosphorus concentrations, these lackluster and borderline depressing results made the localized exceptions seem all the more impressive - perhaps a showcase of what is possible under the right policies.
Our quick analysis yielded about a dozen stations showing what looked to be very impressive results, reflective of significant improvements in pollution concentrations in various rivers and streams around the Bay watershed. We also found another dozen or so stations where improvements were clear, but where the trends were less compelling. We plan to do a separate feature in the coming weeks with more information on these localized success stories. But to summarize, we found these river success stories scattered in almost all of the Bay jurisdictions, spanning across hundreds of miles, through both rural and urban landscapes, and from small streams to the largest of rivers.
In a nod to the late Walt Boynton, we’ll preview one success story in his beloved Patuxent River. The monitoring station at Bowie, Maryland that monitors water quality upstream to the headwaters just south of Mt. Airy, Maryland shows an incredible drop in all three of the major Bay pollutants over the long-term, with plummeting nitrogen, phosphorus, and sediment pollution levels by 68%, 69%, and 46%, respectively, since 1985, despite the massive growth that has occurred in this area since then. And while the rate of improvement has declined over time, all three pollutants have even continued to decline in the most recent 10-year period. For nitrogen pollution, the monitored reductions have exceeded both what the Bay’s water quality model predicted should have happened and what the State had called for under its Watershed Implementation Plan for the Chesapeake Bay.
Once again, we plan to feature more of these river and stream showcases in the coming weeks in a separate release. But suffice it to say, we agree that there are some good news stories to share in this region that lend credence to the UMCES Bay report card’s highest ever marks. From drastically reduced levels of pollution in some of our rivers to a strongly positive trend in the size of the Bay’s dead zone, we do indeed have reasons for optimism.
