BOSTON — Gov. Charlie Baker plans to use pandemic relief money to improve water quality along the Merrimack and other rivers, but the fate of his proposal is anything but certain with Beacon Hill leaders feuding over broader control of the federal funds.

The state expects to get $5.3 billion from the American Relief Plan Act, a $1.9 trillion stimulus package signed by President Joe Biden.

Baker has proposed spending more than half — about $2.8 billion — on water and sewer infrastructure, housing, job training, addiction treatment and other needs.

His plans would put $400 million into water and wastewater infrastructure projects such as improving water quality along the Merrimack River and other bodies of water, where aging outfalls tip hundreds of millions of gallons of sewage into the Merrimack, Mystic and Connecticut rivers each year.

Rep. Lenny Mirra, R-Georgetown, whose district straddles the Merrimack River, supports the governor's plan to divert some of the money to fixing antiquated infrastructure.