OT - Securing a low water crossing

Looking for a 'tool' or method to best way to secure a fairly large low water crossing along a county road. This has been an ongoing issue with individuals parking along the roadway, and walking upstream, but I have also had issues with everything from ATV's, dirt bikes, pickups, and most recently (Saturday night) a UTV with about 4-6 passengers. Saturday night convinced me I need to find some method of at least trying to secure the property along the roadway/bridge. Usually when I confront these individuals the story is "I am within the stream or banks, so I can go where I like". While laws vary from state to state, I have researched my situation and since this is a smaller stream, and not considered "navigable" the landowner controls the stream, therefore anyone leaving the roadway is trespassing, and in any instance "wheeled vehicles" are not allowed in the stream unless it is the landowner, and only to cross from one side to the other. Unfortunately, in most instances these individuals "know" they are right, and usually under the influence of something, be it beer or other substances, and can be difficult to convince otherwise. I did get their attention when I informed them they had to free their $15,000 UTV without assistance from another vehicle as I was calling a conservation agent to assist removing them and it from my property. Initial thoughts on securing the property are to attach a cable from one bank to the other with a breakaway on one bank to allow the cable to simply swing away in the event of a large log or object going downstream during a flood. This stream is roughly 100 feet bank to bank, and while it currently has a slab crossing with metal culverts it gets very large and can easily take out any type of normal fencing materials that are in the stream bed. Any ideas or anyone with similar scenario? Obviously I would rather not put a large investment into something that could end up in the next county in an event such as we had a couple years ago when I experienced debris in trees 8-10 feet in trees over the banks. I know some will insist on ignoring anything I place there, but at least they will be warned and forced to either tear it down or go over/around it, and deter at least a few but the most determined.

If you are in Missouri the first thing to do is contact the Conservation dept and have an agent come out with papers you sign so he can get them for criminal trespass. In Missouri it is in illegal to run an ATV etc in a steam bed and yes if the stream does not run 9 month out of the year yes they are trespassing. As for doing more put in a number of fence posts and paint them purple which is also a no trespassing sign in MO.

I had a problem with quads once,50lbs of 3-4 inch roofing nails on the trail cured the problem in a few weeks

Or dig it deeper ?

been there done that . Been going just above the slab and digging a trench, then mounding a gravel pile so that vehicles would high center if the dropped off the slab, and works well for most vehicles, but just presents a challenge to the ATV, UTV guys, and they drive up, over, and through it. Does keep the 4x4 trucks out for the most part, as they would high center on the gravel pile. Does nothing for the ones on foot though, and even though I post signs on each bank "no public access to creek" they still think they are fine as long as they remain between the stream banks, so I plan on hanging signs within the stream bed (I can print signs and laminate fairly easily/inexpensively).

just a though, but how about running a steel cable across, maybe 5 ft above the water and drilling some 4x4s so the hang down as kind of a fence. dont secure the bottom of the 4x's so they can swing out if something comes down the creek. nail some no tresspassing signs to the 4x's. you could use cable clamps to keep the 4x's from sliding side to side.

As I said if in Missouri take pictures of any truck and get the lience (sp) on the picture and turn it in to conservation and they will get a ticket for driving in a stream bed which is illegal here in MO

actually I spoke Saturday night with a Conservation Agent and provided him with the plate and description of the truck sitting on the bridge. He was going to contact owner of the truck and try to obtain name of individual owning the UTV that was stuck in the stream. The only reason I moved my vehicle and let them leave was that they had small children with them or I intended on letting them speak with the agent. Yesterday when I found beer cans near where the vehicle was stuck, I am wishing I had held them until the agent arrived, as it certainly appears they were not only trespassing, but also drinking with small children in the UTV, stuck up a stream in the dark. I am fairly certain that if they had not been able to winch it out, and I would not allow another vehicle in, conservation would likely had it removed and may have confiscated. Just not certain how that would have played out once they arrived and the UTV was buried on my property in a stream bed. Ironically the vehicle is also illegal to even operate on a public road unless on a road adjoining the owner property unless laws have changed.

Ya no 4 wheeler is suppose to be on any road but many do it on gravel roads. Bet it could open a bag of worms if one of those 4 wheelers hit a car or truck and damaged it. People now days think they can do any thing they want and do not care about other people property

First thing is put up no trespassing so people are warned and have no excuse. It also lessens your liability.

A trail cam to capture licence plates and shots of the vehicle in the wrong place might help.
Forward these to your conservation officer , the word gets around amongst these lowlifes , slowly at first but as more are fined the problem might stop .

try the boulder solution, the bigger the better.

block off all access to the road and let them lose interest in it.

usually a local going thru growing pains

keep the conservation agent involved at all points