Washington ? Mark Twain once described the Mississippi River as worthless for anything except drinking, steamboating and baptizing.

But even Twain never called the Mississippi an “orphan,” the word used by a panel of experts Tuesday to describe what is happening to America’s most famous river due to federal neglect.

In a 229-page report two years in the making, the National Research Council blamed the U.S. Environmental Protection Agency for failure to coordinate state efforts to manage water quality, leaving a system of patchwork monitoring that makes it hard to assess the river’s health.

David Dzombak, a Carnegie Mellon University environmental engineering professor, chaired the 13-member panel that studied the river’s management. He said the government’s limited attention to the Mississippi doesn’t match the river’s value to the nation in terms of economics, ecology or cultural importance.

Benjamin Grumbles, the EPA’s assistant administrator for water, responded by saying his agency “is committed to increasing efforts with all of our partners to improve the water quality and monitoring of the Mississippi River Basin.”

The panel noted that this week marks the 35th anniversary of the signing of the Clean Water Act, the nation’s first full-scale effort to stanch the flow of pollution into rivers and lakes. The law halted much of the industrial pollution that once poured into the river, the study said.

But the Mississippi has a significant new problem: farm fertilizer runoff that chokes the river and its tributaries with nitrate pollution on the way to feeding a New Jersey-sized “dead zone” of oxygen-impaired water in the Gulf of Mexico.

The Clean Water Act “was designed for those things that the public perceived as the 800-pound gorilla,” said panel member Otto Doering, a Purdue University agriculture economist. “Now we’ve got another 800-pound gorilla.”

The panel recommended that the EPA hasten efforts to promote cooperation among states while pushing for limitations on nutrient pollution.

But stemming farm pollution will be challenging, the report’s authors conceded, considering that the Clean Water Act covers agriculture only indirectly. The study concluded that the Agriculture Department needs to play a much bigger role in the river’s health with programs that “widely and aggressively” reward farmers for better environmental stewardship.