A study released Thursday says local jurisdictions must do more to protect the health of the Potomac River and encourages more incentives for property owners to green up their homes and other buildings.

"We wanted to sound an alarm -- there's a tsunami that's coming and this storm is going to wreak havoc on the Potomac unless we take action now," said Hedrick Belin, president of the Potomac Conservancy, the group that issued the report.

Belin and others noted that the river's poor health could only get worse as more land is developed to accommodate the region's growing population.

"That increased development out there is going to make this even more of a challenge," said Richard Batiuk, associate director for science at the EPA's Chesapeake Bay Program. "We still have this mindset [of] taking water and running it off as quickly as possible and not thinking about it after it goes into that drain."

Storm water runoff is one of the biggest polluters of the Potomac, they said. More pavement means fewer places where water can be absorbed back into the ground. Instead, it picks up pollutants as it runs along impervious surface and into drains that dump either directly into the Potomac or one of its tributaries.

That pollution is causing deformities in the river's fish. For example, most of the river's male smallmouth bass are also producing eggs.

Conservationists did commend some local jurisdictions for their part in reducing runoff. The District is a leading city in its number of green roofs and also requires new buildings in the city to be certified as green buildings. Maryland is also looking at increasing the fee it charges property owners for the size of its impervious surfaces.