In a recent annual review, the overall health score of Chesapeake Bay was observed to have deteriorated, primarily due to extreme rainfall patterns experienced during the hottest recorded year. Released by the University of Maryland Center for Environmental Science (UMCES), the report card downgraded the estuary’s grade to a C from the previous year’s C-plus, which was the highest rating since 2002. The fluctuation reflects the growing impact of unusual weather patterns.
Heath Kelsey, the director of the UMCES Integration and Application Network, remarked on the underlying trends, noting a gradual improvement in the Bay’s health from the 1980s through to the present, though recent weather extremes may have influenced this year’s decline. Last year’s record heat, combined with irregular rainfall patterns, contributed significantly to these findings.
The report explained how parts of the watershed experienced brief but intense downpours that led to runoff instead of soil absorption, increasing the flow of fertilizers, dirt, and debris into the waterways. Bill Dennison, UMCES’s Vice President for Science Application, elaborated on how climate change has increasingly altered the Bay’s environment. Specific events, like Maryland’s prolonged summer drought interrupted by intense rainfall, exemplify the climate’s shifting influence.
Such conditions led to crops receiving insufficient water to absorb nutrients, resulting in excess nitrogen and phosphorus being washed into the bay during rains. Dennison expressed concern about these trends, fearing them as the “future” with erratic droughts and floods becoming more prevalent. These environmental trends negatively affect aquatic life, as the warmer winters and higher temperatures reduce oxygen levels essential for fish and shellfish.
Despite this year’s dip in grade, the report highlighted some positive long-term trends, particularly in dissolved oxygen levels and aquatic grass growth, which are crucial for water quality and shoreline protection. These improvements are credited to extensive management efforts involving upgrades to wastewater treatment and nutrient reduction programs at multiple governmental levels. The presence of excessive nitrogen and phosphorus has been somewhat mitigated, an encouraging development since these nutrients commonly lead to damaging algal blooms.
On the downside, the report recorded a concerning decline in water clarity and chlorophyll-a concentrations over time. The latter serves as an indicator of phytoplankton populations and water quality, areas in need of continued attention and improvement.
UMCES, celebrating its centennial this year, also reviewed the health of the bay’s larger watershed, spanning six states and the District of Columbia. For this, the watershed received a slightly better grade of C-plus. The overall evaluation included ecological, societal, and economic factors, with heat vulnerability emerging as a significant challenge. Communities throughout the watershed are increasingly stressed by rising temperatures, inadequate tree coverage, and growing areas of pavement.