U.S. Priority Tributaries

Ten U.S. tributaries were assigned targets for either 1) total annual phosphorus and/or 2) spring soluble phosphorus (defined as March through July). Annual loads contribute to hypoxic (low oxygen) conditions in the bottom waters. Soluble phosphorus is readily taken up by algae and can spur rapid growth or “blooms” near the surface.

Phosphorous in spring

Status of the six U.S. priority watersheds assigned a target to reduce spring (March through July) dissolved phosphorus loads (2014 - 2024). 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

Status of the nine U.S. priority watersheds assigned a target to reduce total annual phosphorus (2014 - 2024). Source: EPA

40% Maumee River (target met 4 of 10 years)
40% Portage River (target met 4 of 10 years)
60% Sandusky River (target met 6 of 10 years)
20% Huron River, Ohio (target met 2 of 10 years)
100% Vermillion River (target met 10 of 10 years)
50% Cuyahoga River (target met 5 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)