Is your local river among those flowing merrily along, or is its health threatened by development plans? A conservation group has issued a new report ranking the 10 rivers most at risk this year of becoming flooded or their habitats threatened because of industrial activity.

American Rivers, a Washington. D.C.–based organization, ranked the rivers based not on how polluted they are, but whether they're imminently threatened by development plans, mines or dams.

Topping the list is the Sacramento–San Joaquin river system, which flows from the eastern Pacific Coast Ranges to the western Sierra Nevada before emptying into California's San Francisco Bay. The group warns that a levee failure there could jeopardize the water supply of the 25 million people who depend on it (by making the water too salty to drink). In addition, it says that pumps that feed the water supply have reversed the rivers' natural flow, causing fish populations to decline.

“Unless we overhaul the way we manage water supply and flood protection on the Sacramento–San Joaquin, the lives of millions of people and the entire economy of the state of California will continue to be jeopardized,” Rebecca Wodder, president of American Rivers, said in a statement released with the report. “It’s time for 21st-century solutions to restore the health of these rivers and protect the health, safety and quality of life of Californians.”

Jerry Johns, deputy director of California's Department of Water Resources, told the Associated Press that the group gave short shrift to the state's efforts to improve the health of the delta and its main tributaries.

The other waterways on the endangered list are, in descending order: the Flint River in Georgia; the Lower Snake River in Idaho, Oregon and Washington State; the Mattawoman Creek in Maryland; the North Fork of the Flathead River in Montana; South Carolina's Saluda River; Pennsylvania's Laurel Hill Creek; Arkansas' Beaver Creek; the Pascagoula River in Mississippi and the Lower St. Croix National Scenic Riverway in Minnesota and Wisconsin.

Headwaters of San Joaquin River/jcookfisher via Flickr via Wikimedia Commons