One such site in Austin is on the east side underneath the 183 and Montopolis bridges which I have explored and monitored since 1988. A heavily used site for access to the river, up to a few years ago, users had open access to drive to the river bank...and into the river which led to vehicles in the water all the time with pollution and damage. Now a barrier designates a parking area and vehicles are kept out of the river. However, other official meddling is limited since TexDOT will tear up the site at some point to finish work on 183 and control this right-of-way under the bridge.
In the meantime, this place is heavily used for legal and illegal recreation, and nonhumans have claimed and reclaimed the marginal space as home. Below are some images of one of my favorite places in Austin.