Updated

A study finds states in the Chesapeake Bay watershed have made strides in reducing pollution in the nation's largest estuary. But it found many jurisdictions in the six-state watershed are falling short in curtailing pollution from farming as well as urban and suburban runoff.

The study is being released Wednesday by two environmental watchdog groups, the Chesapeake Bay Foundation and the Choose Clean Water Coalition.

Advocates say the report marks the first time they can measure how well states have done on short-term commitments — or two-year milestones — for ridding the bay of pollutants that have harmed crab populations, fish and underwater grasses.

President Barack Obama issued an executive order in 2009 placing the federal government in charge of overall bay restoration after years of unsuccessful state-led efforts.