Well over half of the Chesapeake Bay still is polluted, but experts say water quality has improved significantly — and, in fact, is now the best they’ve ever measured.
New preliminary data from the Chesapeake Bay Program indicates that about 42 percent of the bay and its tidal tributaries met clean water standards from 2015 to 2017, while 58 percent failed to do so.
Water quality in that period ranks as the highest achieved since monitoring began in 1985.
“Improvements in water quality take time, but we are finally seeing a positive response to the many restoration efforts of our partners,” said Dinorah Dalmasy, co-chairwoman of the CBP Water Quality Goal Implementation Team.
The new assessment is a 5 percent increase over the 40 percent attainment reached in 2014-2016. Experts credit the improvement to less algae growth and boosts in underwater grasses and in dissolved oxygen in the open waters of the bay.
Algal blooms are fueled by too much nitrogen and phosphorus dumped into the watershed. When those blooms die, the decay process sucks up dissolved oxygen and creates “dead zones” lethal to marine life.