80% of the lake's water flows in from the Detroit River, with only 9% coming from all of the remaining watersheds combined.
Agricultural, industrial, and residential land use are the primary nonpoint sources of pollution in the Lake Erie Basin.
Habitat and flow alteration cause siltation and sedimentation issues which can require dredging.
Fertilizer runoff from farms and residences and unplanned releases from sewage treatment plants promote eutrophication through nutrient and organic enrichment, bacterial contamination, and the appearance of ammonium hydroxide.
Industrial land use adds metals that flow into the basin and cause sediment contamination.