Investigation on a stormy night

You find yourself the next morning outside Public City Records for City Hall entering and see Pat working. They make eye contact and nod before finish writing something down in a book and clicks a few things on the computer next to them before they come over.

"You come by for a social call or work?" they ask with a smirk regarding you.

Pat inspects the map and his brow furrows as he looks at various points, "Well it has our stamp. It's a public record and besides a fee to have them printed anyone can request it. Possibly hiking I guess but these lines here are hand written." he begins to explain tapping the map, "The map was topographical but these lines hand written in are measuring the changes in waterways over several decades. Not sure what to make of that. It's not really an area you can purchase cheaply, it's state owned and open to the public. Not much out there due to the area's nature, hilling enviroments with little resources have little value, even logging would be a challenge since it's cost too much to flatten the area for equipment to ingress." he explains looking around at various notes on the map, "Are these food or coffee stains?" he asks squinting at a few dark reddish small stains you notice here in there with more visible light.

"Ok, be careful if you're out hiking about though. And definitely let us know if you find something odd like a major change in terrain and topography so we can update our records accordingly." he replies.

Sal finds himself going to the library for further research.

Sal spends enough time at the library that he goes out for lunch and comes back with coffee. With a search for anything odd in the library resources he finally finds a few things in newspaper archives while scrolling through them on microfiche. There's a small piece about a missing young boy fifty years ago, oddly enough he was never found. Looking into the waterways going through the wooded area mentioned by Pat you're curious why one would move or interrupt the flow of water's natural route. Looking at older maps to the current one you've borrowed you figure you have a general idea where the source was.

Sal eyes the pile of information to review once he gets closer to the forest in his bag getting dangerously close to his lunch and drink as the car is jostled about, the closer to the forest on the back road he's on the rougher it gets. You pull into what looks like a simple lot by a footpath into the green section on the map you're looking at the woods. You have a lot of light left today and information to review or learn before going in unless you wanted to take it along.

Sal looks around and realizes he's not that good at tracking. He realizes he's not that good at noticing things as well since he falls and sits up realizing he's in an old riverbed. Looking at the map it's someplace a waterway was before it was moved.

Rollin'

Sal knows exactly where he is looking at the empty riverbed and where it beds when he looks at the map. You realize water way although it's changed over time for some reason it seems the origin point is the same.