Hoping a fellow boater has some advise?

I am an avid boater and delivery captain with many years experience. I am at wits end with an ongoing issue we are having at our marina (I boat on the Illinois river around mile marker 240). Our fuel docks are on the river and are posted "NO WAKE" zones. We continue to have ignorant boaters plow past the fuel docks causing damage to both boats and people, yet there are no DNR or USCG officers to enforce the law. I am hoping that someone on here could have a recommendation on how to tackle this issue, we have repainted our signs and added reflectors. We used to have "NO WAKE" bouys, but they actually ran those over!!!!! PLEASE HELP