As activist and former state senator Gerald Winegrad notes, something like 90 percent of the bay's waters are considered impaired and fail to meet federally mandated water quality standards.  Environmentalists argued successfully in court that that represents a continuing violation of the federal Clean Water Act, and EPA agreed to consent decrees requiring it to put the bay on a pollution diet, bureaucratically known as a "total maximum daily load."

Reaction to EPA's final plan varied.  Environment Maryland echoed the assessment of EPA officials that it represented a historic effort - as North America's largest estuary, it's also the largest water body in the nation ever put under a single restoration plan.

"It's hard to imagine a better New Year's resolution than providing clean water to our families and communities," said Environment Maryland's Tommy Landers.  He called Maryland's cleanup plan "promising," pointing to the state's vow to revise standards for how much phosphorus farmers can put on their crops, which could curtail the use of poultry manure as fertilizer on the Eastern Shore.

(BTW, the Shore's poultry industry produces upwards of a billion POUNDS -- not tons -- of manure annually. I resolve to check my facts more carefully on deadline in 2011 after getting the two confused in today's print story.)

But diets only work if you stick to them, changing hard-to-break habits.  And it remains to be seen if the latest, seemingly toughest cleanup plan ever produced for the bay will do more than consume mountains of paper to print it.

As an example, although Maryland's bay cleanup plan has been widely regarded as the most ambitious and thorough of any in the region, a number of key pledges in there are conditional or delayed a year or more.  Though the state faces a looming $530 million shortfall in its efforts to upgrade the largest sewage treatment plants around the bay, officials put off acting to close that gap until 2012, the year before the funds start to run out.

Environmentalists aren't the only ones anxious about such delays.  Tom Farasy, president of the Maryland State Builders Association, said his industry supports an increase in the $30 annual "flush fee" levied on all homeowners in Maryland to cover sewage plant upgrades.  Builders also want to see every county and municipality in the state required to raise funds to retrofit storm drains and invest in other measures to control polluted runoff from city and suburban streets and parking lots.

Such a position might seem self-serving, as builders have long complained that their share of the bay's pollution is tiny compared with farmers and older communities built before any runoff controls were required.  They want to avoid being subject to even more costly runoff controls on new development or redevelopment.

But sewage plant upgrades and urban storm drain retrofits are cornerstones of Maryland's plan to clean up its portion of the bay.  The O'Malley administration has pledged to get 70 percent of its needed pollution reductions by 2017 and all of them within a decade.  The bill for that has to be paid by someone, and the work won't begin until funds are there to pay for it.  Local government, already threatened with having to pick up teacher pension costs, is likely to buck any state or federal requirement it spend more on pollution controls.

"It's going to be a really incredible political challenge, because obviously money is scarce," agrees Swanson, the longtime bay commission director.  "This will require a lot more expense," she adds.  Without "the luxury of extra money" to spend to accelerate pollution reduction efforts, she argues, "What we need to do is invest monies we do have in the smartest way possible."

Winegrad and Swanson have both been involved in the bay restoration effort since its beginning.  The veteran former legislator from Annapolis says he finds it hard to be optimistic, given the history of failed cleanup plans and promises.  

Swanson acknowledges the effort's shortcomings, but retains a sense that progress is being made.  The pollution diet and cleanup plans finalized this week couldn't have been written 15 years ago, she says.  Scientists have improved their understanding of the bay and its problems and how to fix them since then.

Indeed, the bay has been one of the most studied ecosystems in this country, if not the world.  So the test is, can all the science that's been brought to bear here motivate politicians and their constituents to do what's needed to restore the bay's water quality?

"If the Chesapeake Bay cannot meet its (diet), I doubt we can meet it anywhere," Swanson says.  "I think we can meet it, but we have to try."

The challenges start anew in 2011, as the states are required to submit a second set of cleanup plans by June spelling out how pollution reductions will be parceled out at the local level.  Already, the Maryland Association of Counties is asking that that deadline be pushed back, to give local officials more time to figure out what's expected of them and how to pay for it.

Meanwhile, by the end of next year states must also show if they met two-year cleanup "milestones" they set in 2009. 

'It is clear .. that the hardest work is still to come," said Chesapeake Bay Foundation President William C. Baker.   He added that it would be essential for EPA to continue to play the tough-cop role, imposing consequences if states fall short.

Howard Ernst, a critic of the bay foundation, seems to agree with Baker on this point.  Ernst, a political science professor at the Naval Academy and author of two critical books on the bay cleanup, suggests the diet will only work if EPA sticks to its pledge to punish the states - by blocking permits needed for new industries and growth, for instance - if they fall off the pollution-reduction wagon.  That won't be easy, either, as EPA has never gone to the mat in that way with states before.

"Like all New Year's resolutions," Ernst emailed, "the EPA's success should not be measured by the initial goal of their Chesapeake Bay diet, but by their resolve when the hunger pains begin."

(Baltimore Sun Photos:  Top - Fishing Creek, 2007, by Doug Kapustin; Middle - Watermen clean oyster bars off Annapolis, 2008, also by Kapustin; Bottom - Gov. O'Malley and EPA Administrator Lisa P. Jackson in Annapolis, 2010, by Amy Davis)