As required by state legislation signed in 2015 (House Bill 64), the Ohio EPA has completed its second statewide study identifying sources and estimating the annual amount of phosphorus and other nutrients flowing from the state’s watersheds into Lake Erie and the Ohio River. According to the study, there’s no clear trend of an overall decrease in loading in most watersheds, especially in nonpoint source dominated watersheds like the Maumee where the loading in 2017 was the highest of the years reported.
Other highlights include:
- The Muskingum River and Sandusky River watersheds had substantial reductions in loading from industrial and municipal sources over the five years in the latest Nutrient Mass Balance Study. Annual nutrient loads from industrial and municipal sources decreased 34 percent between water years 2013 and 2017.
- In the Sandusky River watershed there was a 25 percent decrease in phosphorus loads from water year 2013 to 2017, but the change was not a result of regulatory action.
- In the Maumee watershed, there has been no discernable decrease in phosphorous or nutrient loading to Lake Erie, which continues to exceed the 40 percent phosphorous reduction requirement.
- Also in the Maumee watershed, 88 percent of the phosphorous contributed to Lake Erie is from nonpoint sources including agriculture.
The study examined phosphorus and other nutrients from agriculture and other nonpoint sources, municipal and industrial wastewater systems, as well as home sewage systems, which make up the vast majority of nutrient sources. It covered the Maumee, Portage, Sandusky, Vermilion, Cuyahoga, Great Miami, Scioto and Muskingum watersheds, and included some direct tributaries to Lake Erie, which collectively represent surface water quality from 66 percent of the entire state.