On My Mind…

“I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it;
but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind.”
–Lord Kelvin (1824–1907)

2025 Chesapeake Bay and Watershed Report Card

We reported in the Spring 2026 issue about the start of the Connecticut River Conservancy’s two-year effort to create the first-ever watershed-wide report card for the ecological health of the Connecticut River. To learn how a mature watershed report card has evolved elsewhere, we looked to the Chesapeake Bay, a much larger watershed, whereby we might predict the kinds of information possible for the Connecticut River watershed in the years ahead. Dr. Heath Kelsey, Director of Integration and Application Networks for the University of Maryland’s Center for Environmental Science, helps create watershed report cards for a living. He and his team, therefore, seemed like a good place to start.

In his 20 years working on reports cards for the Chesapeake Bay, Dr. Kelsey has developed a process for data collection within a watershed that reflects what communities want and that allows for differences within a watershed. For the Chesapeake, two separate report cards are generated: one for ecological health (reflected on here) and a second for economic and social health (to be considered in a future issue). The most recent reports were generated before the disastrous sewage overflow into the Potomac River, which feeds into the Chesapeake Bay, in early 2026.

Kelsey’s approach to developing a watershed report card is to organize public comment sessions in different communities representative of the watershed as a whole. The objective is a serious, measured dialogue between people with disparate interests. In some cases, the only time these groups have previously appeared in the same room were on opposite sides of a courtroom. Kelsey notes for example, “We can have the Nature Conservancy, corn growers, and the Army Corps of Engineers in the same room, all learning from each other, especially about values that are different from their own.”
The attributes of ecological health for the Chesapeake Bay are well-understood. In the 2025 report card, water quality received an overall grade of “C.” Seven indicators contributed to that grade.

Dissolved oxygen (DO) was good, receiving a grade of A. It’s hard to have too much of it. Fish and other aquatic organisms need DO to breathe; thus, the more DO, the more biodiversity that is supported.

Chlorophyll a received a D-minus. In moderation Chlorophyll a is essential for aquatic life. Too much, however, can lead to oxygen depletion and indicate pollution.

Benthic Community (a grade of C) represents the small, bottom-dwelling critters and are indicators of a healthy ecology. The more different species, the merrier. (Dr. Andy Fisk writes a column for Estuary about them in his column, “Connecticut River Critters.”)

Aquatic Grasses received a D+, but there’s reason for optimism. The effort to restore 190,000 acres of the bay with aquatic grasses is nearing the halfway mark. According to the Chesapeake Bay Program, aquatic grasses “are sensitive to pollution but quick to respond to improvements in water quality.”

Phosphorous (A-), while essential for aquatic plant growth, will consume oxygen if there’s too much and lead to algal growth, which is harmful to plants and humans.
Nitrogen (C+), the most abundant element, is the ultimate double-edged sword of river ecology. While all of life needs nitrogen for growth and survival, fertilizers and sewage can contribute to toxicity to humans and aquatic life.

Water Clarity (F) is useful mainly as an indicator of ecological health. Clear water is generally better for plants and fish species. Turbid water is often an indicator of pollution.

The report card for the Chesapeake Bay is readable and understandable by the lay reader. Kelsey says every element on the report card can be drilled down to the raw scientific data that is then aggregated for the entire region for the report. His team uses color codes and arrows so that anyone can quickly comprehend the ecological status of the Chesapeake Bay, what priorities are needed to stem the tide of problems, or where to add, continue, or increase restoration measures. The chart above shows overall health trends by region within the Chesapeake Bay watershed.

Importantly, a watershed report card should be adaptable to, and reflect, climate and weather changes.

There is much we can learn from the Chesapeake Bay’s efforts to track, record, and communicate the health of the bay. We look forward to what we will learn from the report card for the Connecticut River.