This Thursday, the University of Maryland's Center for Environmental Science will be releasing its second-annual Chesapeake Bay report card.

As those of us who follow these things know, there are dozens of reports on the health of the bay. What sets the UMCES report apart is that it grades the rivers, and it uses real monitoring data, crunched by a team of scientists, database experts and water-quality analysts, to come up with a way to grade the rivers. As far as I know, it's the first such report to look at all of the rivers in a comprehensive way.

Nobody's expecting good news: the question is always, how bad will it be? Last year, even the scientists who worked on the report were surprised to find that the Choptank, which meanders through some of the prettiest rural Eastern Shore towns, was ranked second most polluted. (They were not surprised, however, that baltimore's own Patapsco scored the worst.)

The Patuxent River also fared badly last year, despite having a very involved riverkeeper organization that has been fighting for cleaner water and better land-use during this legislative session.

There was a smidge of good news last year, for the Upper Bay at least: the Sassafras/Bush/Gunpowder rivers got passing grades of Cs. Those are heavily influenced by the Susquehanna.

It's hard to say which rivers will pass this year and which will fail. But we'll let you know soon after the press event.