U.S. Priority Tributaries

Phosphorous in spring

Status of the six U.S. priority watersheds assigned a target to reduce spring (March through July) dissolved phosphorus loads (2014 - 2023). Source: EPA

20% Maumee River (target met 2 of 10 years)
N/A Toussaint River
70% Portage River (target met 7 of 10 years)
20% Sandusky River (target met 2 of 10 years)
N/A Huron River, OH
N/A River Raisin

Explore the data on the Great Lakes Commission ErieStat website.

Phosphorus throughout the year

Limiting the annual total phosphorus load is thought to keep oxygen concentrations in the bottom waters of Lake Erie at an acceptable level to avoid hypoxia (these low-oxygen areas are sometimes referred to as "dead zones").

Status of the nine U.S. priority watersheds assigned a target to reduce total annual phosphorus (2014 - 2023). Source: EPA

40% Maumee River (target met 4 of 10 years)
40% Portage River (target met 4 of 10 years)
50% Sandusky River (target met 5 of 10 years)
30% Huron River, Ohio (target met 3 of 10 years)
90% Vermillion River (target met 9 of 10 years)
40% Cuyahoga River (target met 4 of 10 years)
30% Grand River (target met 3 of 10 years)
50% Detroit River (U.S. portion) (target met 5 of 10 years)
40% River Raisin (target met 4 of 10 years)