Last Friday the University of Maryland Center for Environmental Science released their 11th annual report card on the health of the Chesapeake Bay. Overall, in 2017 the Chesapeake Bay Scored 54% for the University’s Health Index, the same score as 2016. There are seven indicators that make up the Bay Health Index for the Chesapeake Bay Report Card; total phosphorus, total nitrogen, dissolved oxygen, water clarity, benthic community, chlorophyll and aquatic grasses. Each indicator is compared to scientifically derived thresholds or goals and scored to determine the overall grade.
Total phosphorus, total nitrogen, dissolved oxygen, and aquatic grasses are showing positive improvements. These improvements are encouraging for water quality, and have positive impacts on the ecosystem. Water clarity and chlorophyll a have significantly declining trends. Benthic community shows no significant change in health over time.
Overall Chesapeake Bay Health Scores have been variable in the past and bounced around a bit. However, since 2015, Chesapeake Bay Health Scores have consistently been in the high C range (53, 54, 54). These consecutive scores have contributed to an overall positive trajectory based on the average trend as seen below. It does seem odd that the Chesapeake Bay health has seemingly lost the variability that characterized it in the past. This may be an indication of the method of evaluation. I think more time is necessary to actually see if the current trend is sustainable and if the Health Index can break out of the range it has been stuck in for two decades
Over the years there have been changes in the methods of evaluation. Going forward, University of Maryland Center for Environmental Science plans to improve the Chesapeake Bay Report Card over the next several years. This process will incorporate new indicators for Chesapeake Bay health including some indicators of watershed health.
The new indicators are planned to reflect goals for sustainable fisheries, healthy watersheds, and engaged communities outlined in the Chesapeake Bay Agreement. The planned stakeholder-centered approach will hopefully allow for a stronger report card and improved understanding of how ecosystem health interacts with other factors throughout the Chesapeake watershed.