It's a bridge to access the water intake building. I don't know if it's private for P&G or part of the KCK water supply system.
I think it may be an entrance to a pump house or something.
My best guess is a some sort of rail to river access. Proctor & Gamble has a facility nearby so maybe its a way to access the river
I believe this was a pump house for the Kaw Velley Power Station right there currently moth balled.