By far the largest initiative to protect Lake Erie is the group Toledoans For Safe Water (Link to their website and Link to their Facebook Page).
Toledoans for Safe Water Logo
In February 2019 they successfully managed to pass their “Lake Erie Bill of Rights” law, an initiative with over 11,000 people signing on, which would protect the lake by defining Lake Erie and its ecosystem as having the right to exist and flourish, the right for the people of Toledo to have a “clean and healthy environment”, including the lake, and a right for the residents of Toledo to self-govern. This bill held corporations and governments liable for violations of those rights, and theoretically fine them the maximum amount allowed for violations. Sadly, however, the law was ruled unconstitutional in court (Toledo declined to appeal the ruling, citing budgetary constraints). Still, Toledoans For Safe Water continues to fight for the lake.