I live about an hour away and I’ve been down there recently to look for artifacts. No luck. It’s surprisingly difficult to learn where exactly where to look for them.
I get down on the Walnut river a little down stream from Etzanoa. Watching YouTube clips of artifact hunting says on the sand bars and banks after a rain is best.
Please don't go collecting artifacts like that; leave it to the pros.
Being able to collect detailed records of archaeological finds, including things like soil stratigraphy that require very specialized knowledge, is an important part of preserving the heritage associated with these artifacts. An artifact that's been stripped of its provenance has been stripped of almost all its scientific value.
Genuinely curious, how do archaeologists catalogue items found in sand bars? Through correlation with upstream sites? I can't imagine stratigraphy would be terribly helpful.