Since the initiative's inception in 2010, $1.6 billion has been used to fund 3,068 projects to address invasive species, harmful algal blooms and loss of fish and wildlife habitats, the letter said.
The Great Lakes provide drinking water for 40 million people, contribute $10 million to tourism each year and support hundreds of thousands of jobs, the letter said.
The initiative also targets several designated areas of concern, including the Grand Calumet River. The river — first named an area of concern under the Great Lakes Water Quality Agreement of 1987 — originates in east Gary and flows 13 miles through Gary, East Chicago and Hammond.
Decades of industrial activity have caused a buildup of contaminated sediment at the bottom of the Grand Calumet River and Indiana Harbor and Ship Canal, according to the EPA website.
"Contaminants include PCBs, PAHs and heavy metals such as mercury, cadmium, chromium and lead," according to the EPA. "High fecal coliform bacteria levels, biochemical oxygen demand, suspended solids, and oil and grease create additional problems."
The canal and parts of the river have been dredged in recent years.
"We have seen the tragedy and heartbreak that occurs when our nation’s clean water programs fail. Lead-tainted drinking water flowing from taps in Flint, Michigan. Toxic algal blooms shutting down Toledo, Ohio’s drinking water system. These are just two examples from a list longer than is acceptable in the United States of America," an alliance news release said. "If anything, evidence indicates that federal environmental protections should be more aggressive and accountable, not less."