My recent obsession in Water Quality(and Urbex) has landed me an awesome resource. This is an entire map of the flood systems of Denver, CO. The map can be somewhat hard to use; DM me if you want help using it.

Map: https://geospatial...b9876a8364718a529a

GIS maps are a delight to the drainer. Do your homework and check the expanse of the drainage basin and be sure it won't rain in that area.

Enjoy!

This is quite similar to some of the GIS maps produced by a few of the local municipalities here. It's quite game changing when it comes to doing lazy recon work on new systems to explore!

I was able to find one of these for Colorado Springs, as well!

https://gis.colora...viewer=springsview

Such a helpful resource for drainers, the only problem I have with the one here is that it doesn't really specify drain sizes, so it's hard to tell which ones are actually explor-able and which are too small to consider. But still; very cool for getting an overall look at the infrastructure.

Yeah as someone thats gotten good at reading the city maps, and seen most the drains just watch out! some of our best spots flood like hell and id never go in one if there is even a slight chance of rain. why I like the mines more now lol

WTF? These are publicly accessible now? Man, what folks went through to get these maps 15 years ago. What's online here is quite a few years behind...

Posted by Garrett Stopmotion Yeah as someone thats gotten good at reading the city maps, and seen most the drains just watch out! some of our best spots flood like hell and id never go in one if there is even a slight chance of rain. why I like the mines more now lol

A lot of the mines I've been in have signs of cage ins which can happen without notice, so I tend to not feel as relaxed in them as I do in drains where there is a controlled danger, but I totally get what you mean.

Posted by Floodway ...the only problem I have with the one here is that it doesn't really specify drain sizes, so it's hard to tell which ones are actually explor-able and which are too small to consider.

I enjoy the hunt. Finding 10 small drains in a row makes the next big one or the more rewarding.

Also, to some extent you can increase your odds - usually longer systems with lots of tributaries would be bigger downstream.
I also look for sections where the tunnel opens up again back into a waterway (so you have an inlet & an outlet rather than the tunnel just shrinking) as sometimes, even if they're not that long, they may be bigger or have a good feature. If they're part of a bigger river, all the better - they may have only put it underground for a bit while it runs under a shopping center or a freeway.

Even a percentage of the 5ft or smaller drains could have an old bigger section. I used to always check smaller drains that went under railway lines as they'd often have bigger older sections there.

Anyway, definitely not meaning to talk down to anyone - I just spewing out my thoughts.

Cheers