Decades of effort to restore the Chesapeake Bay are paying off in cleaner water, more underwater grass beds and an uptick in important species such as blue crabs and oysters, says a new report released Tuesday.
Some areas still need work, experts say — in particular, planting more forest buffers and fencing more livestock from streams to keep sediment and nutrient overloads from polluting the watershed.
But the overriding message of this year's "Bay Barometer," said Nick DiPasquale, director of the Chesapeake Bay Program, is that "it appears we're moving in a positive direction on a number of indicators."
The Chesapeake Bay Program released the data along with the Virginia Institute of Marine Science in Gloucester Point and the Chesapeake Bay offices of the National Oceanic and Atmospheric Administration and the U.S. Geological Survey.
The report uses data compiled in 2014 and 2015 from direct monitoring and computer simulations to provide a snapshot of bay health and restoration efforts.
One of the highlights of that data, the report says, is a 47 percent jump in the number of adult female blue crabs, an iconic species in the bay, to 101 million.
"It's a modest increase," said Bruce Vogt at NOAA. "But it bodes well."
The new figure is far better than the 68.5 million adult females from last year's report, but still less than half the target of 215 million that experts say would constitute a healthy stock.
Oysters also fared well, the report notes, as efforts to rebuild the stock by restoring and seeding habitat led to more than 2 billion oysters seeded and 350 acres restored in Harris Creek in Maryland.
"The scale is about the size of the National Mall, so this is a major undertaking," said Vogt. "I think this is probably the most positive story we've got."
Similar efforts are now underway in five other tributaries, he said, including the Lynnhaven and Lafayette rivers in Hampton Roads and the Piankatank River on the Middle Peninsula.
Meanwhile, harmful nutrient and sediment loads dipped well below long-term averages between October 2013 and September 2014, data show, when about 285 million pounds of nitrogen, 17.5 million pounds of phosphorus and 3.62 million tons of sediment reached the bay.
Nitrogen and phosphorus pollution fuel massive algal blooms that decay and suck oxygen from the water column, creating dead zones. Sediment clouds the water, preventing sunlight from reaching underwater grasses, and suffocates bottom-dwelling shellfish.
A combination of clearer water, fewer damaging storms and warmer water temperatures may have fueled the rapid expansion of the warm water-loving widgeon grass between 2013 and 2014, said VIMS scientist Robert Orth, while eelgrass has recovered more modestly.
Underwater grass beds in the bay expanded from 59,711 acres to 75,835, the report shows. That's 41 percent of the goal of 185,000 acres.
These plants are not only vital habitat for blue crabs, Vogt said, but also sequester heat-trapping carbon dioxide, which makes them "good for the bay, the world's oceans and our climate."
Meanwhile, only 114 miles of forest buffers were planted along waterways between July 2013 and June 2014 to stabilize banks and keep pollution from entering the estuary. The report says it's the lowest number in the last 15 years.
Last year, a task force was assembled to address that decline, said DiPasquale, noting that funding for riparian buffers and livestock fencing programs has also declined.
The CBP is a regional partnership of federal and state agencies, academic institutions, environmentalists, citizen groups and others. It's led by the U.S. Environmental Protection Agency.
In 2010, the EPA put Virginia, the five other bay states and the District of Columbia on a so-called pollution diet, directing them to reduce nutrients and sediment loads to the bay. They must have pollution-reduction measures in place by 2025 that will lead to a healthy estuary, and until then must meet two-year milestones to ensure progress.
The Bay Barometer is designed to track and guide pollution-reduction efforts.
To read more of the Bay Barometer, go to www.chesapeakebay.net
Dietrich can be reached by phone at 757-247-7892.