A new report from the Interstate Commission on the Potomac River Basin (ICPRB), the organization tasked with assembling and reporting the data, shows a 1.4 percent improvement in overall stream health throughout the Chesapeake Bay watershed over the past six years.
The tracking tool is a Chesapeake basin-wide index of biotic integrity for stream macroinvertebrates, known as Chessie BIBI for short. One way scientists gauge the health of a stream is by figuring out who calls it home. Specifically, how many and what species of benthic macroinvertebrates — the scientific term for creek critters like dragonfly and stonefly larvae — are living at the bottom of a stream. Some creek critters need healthy streams to live while others are more tolerant of poor conditions.
“It would be too expensive to monitor for every possible contaminant in every part of the stream,” explains Dr. Claire Buchanan, director emerita at ICPRB and one of the study’s co-authors. “The health of the creek critters gives us a good gauge on the overall health of the stream because their numbers show a predictable pattern depending on their sensitivity to pollution. If something is going wrong — or right — they’re going to tell us.”
The Chessie BIBI tracks percent improvement over 6-year intervals to capture the various monitoring schedules across the watershed.
In the past quarter century, Chessie BIBI has seen which translates to almost 15,000 healthier stream miles overall, according to the report. With the new numbers, an estimated two-thirds of the roughly 145,000 stream miles in the Bay watershed now have Chessie BIBI ratings of excellent, good, or fair.
So, looking at their map, we see a band of streams in relatively poor health along the fall line, where most of the urbanization has occurred. However, despite all the hyperventilation about Pennsylvania not holding up it's end of the Bay Diet by controlling agriculture, the hinterlands of Pennsylvania look pretty good. Maryland's Eastern Shore is a little iffy.
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