O'FALLON, Mo. (AP) — A group developed to help improve management of the Mississippi River Watershed has issued it a disappointing report card, and says urgent action and billions of dollars are required to address flooding and water quality concerns in the nation's largest rivers.

America’s Watershed Initiative on Tuesday released its 2020 report for the Mississippi River and its more than 250 tributaries. The 2020 C- grade is only a slight improvement on the D+ grade the group issued for the watershed in its first report, in 2015.

The watershed, which encompasses two-fifths of the continental U.S. and 31 states, remains threatened by increasingly frequent and extreme flooding as well as aging infrastructure and pollution, the report said.

Kimberly Lutz, the initiative’s executive director, said the watershed faces “pressing challenges.”

“As the United States looks to recover and rebuild our economy amid the coronavirus pandemic, the health and resilience of this critical natural resource —through investments in infrastructure, research, education and flood and water management — must be part of the solution,” Lutz said in a news release.

The report characterized water quality in the system as “very poor” due to increasing sediments and nutrients. It gave a D grade for water quality, flood control and risk reduction. Other factors assessed include ecosystem health, the economy and recreation.

To protect the water system, the initiative called for $2 billion in annual funding through government and private sources to address issues such as river navigation, flood management and the ecosystem. It also urged greater collaboration among river interests and improvements in information gathering and public education.

Report Card Committee Chairman Larry Weber said the challenges faced along the rivers demand urgent action, including “smart investments in scientific information to improve decision-making and coordinated on-the-ground implementation.”

Lutz said the goal of the report card is to provide decision makers and others with information to develop a collaborative approach to managing the watershed. She said the group plans to release a new report every five years to help track progress and shortfalls.

The report card was developed jointly with the University of Maryland Center for Environmental Science. The initiative, founded in 2010, comprises representatives from business and the public sector with expertise in river management and conservation issues.