The Chesapeake Bay brought home its worst report card ever this spring, thanks to a pair of storms that washed huge amounts of nitrogen, phosphorus and sediment into its mainstem.

For 2011, the Bay scored a D+ overall, with two rivers - the Patuxent and the Elizabeth - earning Fs. The Upper Western Shore, Upper Bay and Lower Bay all earned Cs, the highest grades. Only two regions improved their score since the 2010 report card, but even those were not worthy of gold stars. The Patapsco and Back rivers scored a D- instead of last year's F. And the Lower Western Shore of Maryland (Annapolis area rivers) moved up to a D from last year's F, a move that signified the greatest improvement.

"It's the worst we've ever given, and it's a damn shame, because we've had a banner year, and we're doing so many of the right things," said William Dennison, a vice president at the University of Maryland Center for Environmental Science and the architect of the report card. UMCES began issuing Baywide report cards six years ago, with data culled from real-time monitoring stations in 15 locations.

Weather patterns created a perfect storm of problems. Spring rains clouded the water, blocking light that underwater grasses and plants need. A hot and dry summer contributed to low dissolved oxygen. Then Hurricane Irene actually increased the oxygen because its winds mixed up the water, said UMCES scientist Caroline Wicks. But Tropical Storm Lee, which closely followed, washed vast amounts of sediment into the Bay, leading to "very poor water clarity," she said.

Chesapeake Bay Program Executive Director Nick DiPasquale acknowledged that the report card "means we've got a lot of work to do." But he pointed to a Johns Hopkins and UMCES study showing that, over time, Bay dead zones have decreased. He also said the Susquehanna Flats, despite the damage from Lee and Irene, proved to be resilient. And he said that, in his eight months on the job, he's seen local and state governments as well as environmentalists embrace cleanup strategies.

"The one message that comes across very clearly from talking to people is, 'we're ready to do this. We're ready to get the work done,'" DiPasquale said. He pointed to the ambitious legislative agenda in Maryland, where lawmakers passed a stormwater bill, a septic bill and an increased fee for wastewater treatment.

Dennison presented the report card at an Inner Harbor park in Baltimore that was created to manage stormwater and keep it from entering the Patapsco. The park, which includes porous pavement, rain gardens and benches made out of stone and topped with wood, is designed to catch stormwater and use it to recharge the garden instead of making it part of the problem.

It is a strategy DiPasquale has embraced - in Baltimore and other places - and one he thinks he will see more of in the watershed.

There is, Dennison and DiPasquale agreed, a lot of room for improvement.

"We hope, very much," Dennison said, "that this is the worst report card score we will ever read."

Last year was the first that the Elizabeth River received a grade. The Elizabeth River Project, a nonprofit, has just embarked on several projects to remove sediment and other pollutants from the industrial river, which runs through old Navy shipyards and several toxic sites (See "Elizabeth River Rises from the Depths," July/August 2011).