"Alexa, ask River Rat how high is the Ohio RIver at Cincinnati"
"Alexa, ask River Rat stage Ohio River at Louisville"
"Alexa, ask River Rat water level of Ohio River at Wheeling"
The National Weather Service has an awesome hydrologic information page to help you plan boating and other activities on US rivers. If you just want to know the latest river level, the River Rat skill will look it up for you and answer by voice so that you know what conditions to expect.