It sometimes seems that any land set aside in Kansas for conservation is because the land doesn't have much other use. In this case, the land is owned by the Army Corp of Engineers owing to a reservoir miles downstream (which is too far away to have any consequence). Kansas manages this area between two rivers for hunting, but you won't find any signs showing you the way.
You'll find the Kaw Wildlife Area southeast of Arkansas City. There are not any signs, but head towards the place where the Walnut River meets the Arkansas River, and you'll be there.
There are trails that were once (and still might be) two-track 4wd roads to the river. In any case, you'll want to park well before you need 4wd.
The Walnut River isn't near the size of the Arkansas River, but at least here, the Walnut looks pretty large.
Along the Arkansas River, looking upriver...
...and, looking downriver. The Walnut enters where the Arkansas makes a sharp right turn and the Walnut joins on the left. When the river crosses into Oklahoma, the ar-KAN-sas becomes the AR-kan-saw River.
You'll see and hear lots of birds, and see lots of tiny frogs in the small pools. I saw several large splashes from fish, but didn't see one in action.