Will someone please tell me WTF the Army Corps of Engineers has to do with “granting easements.” These worthless environazi ba$tards need to go back to doing construction on behalf of the Army and GTFO of anything to do with domestic non-military projects. Out here in California they are trying to claim farmers stock ponds as wetlands, subject to “their rules” whatever those rules are who gave them the authority to issue them.
My guess because it’s a native reservation the Feds have to be the ones to give the ROE. States usually have little to say in those.
I suspect that it is because it involves a large body of water (the lake), which is, by definition, a "navigable body of water" in the United States. The Corps of Engineers has engineering authority over such. The Corps does quite a good job when they are allowed to (often prevented by politics). I grew up in South Louisiana literally surrounded by ACOE projects (lower Mississippi levee system, Morganza Floodway, Old River Control Structure, the Bonnet Carre Floodway, and more).
Sometimes they get it wrong, but more often the politicians get involved and over-ride the engineering judgments.