More than 70 percent of the Chesapeake Bay and its rivers and streams are falling short of water quality goals, according to a report released Tuesday.

The "Bay Barometer" report is issued annually by the Chesapeake Bay Program, the federal-state partnership that oversees restoration efforts for the bay.

This year's report includes a new category that combines water quality readings such as dissolved oxygen and clarity. The bay and its tributaries are broken into 291 sections, of which only 29 percent had an adequate score. That's down from a high of 40 percent a few years ago.

"The partnership clearly has more work to do. We know that," said Rich Batiuk, associate director for science at the Chesapeake Bay Program.

Batiuk and other officials cautioned that bay-saving actions such as planting cover crops and reducing urban stormwater runoff may take years before the effects are seen in lower pollution loads and improved water quality. Groundwater in particular takes a long time to reach waterways, making for a lengthy lag time.

"Some of the practices that we implement will take time to show their true reduction effect," said Nick DiPasquale, director of the Chesapeake Bay Program.

The Chesapeake suffers primarily from three pollutants: sediment that clouds the water and the nutrients nitrogen and phosphorus that fuel the growth of algae blooms that rob oxygen from the water.

Maryland and other states that drain into the bay are working under a federally imposed "pollution diet" to reduce pollution in order to improve water quality and wildlife.

The pollution diet mandates that by 2025, there should be enough bay-saving practices in place to improve the bay enough to get it off the federal government's list of impaired waters.

The Chesapeake Bay Foundation, a nonprofit advocacy group based in Annapolis, said in a statement that the report is a "sobering reminder" that the bay still has a long way to go before it's healthy.

The bay foundation said that when governors from Chesapeake Bay states meet next week, they must reaffirm their commitment to meeting the 2025 deadline.

The Bay Barometer report is posted online at chesapeakebay.net.

pwood@baltsun.com

twitter.com/pwoodreporter