Realtime Streamflow Data for the Fox River:
McHenry Dam
Algonquin
Montgomery
Dayton Dam
Mill Creek near Batavia
Blackberry Creek near Yorkville
When you click on the links above, you will get a page from the USGS website that shows the real time water levels of the Fox River where it passes through the towns named. The following description is based on my observations of the Montgomery stream flow data over the past 10 years.
I have it set up so that two graphs will appear that show how the river has come up and down over the last 30 days. I like viewing the last 30 days so I can compare dates. What was the level when I was out 1, 2 or 3 weeks earlier.
The top graph shows the graph height in feet. I've been referring to these graphs for years and I've never got used to reading the graph height in feet. I know it means the river is up an inch, a foot or whatever, but that doesn't tell me how fast the water is moving. The speed of the flow of the water tells me more.
The bottom graph shows the speed of the river in cubic feet per second. This is the graph I've got used to reading. I go out fishing, come home, look at the graph and make a mental note of where it is and how that made the river look.
What I've learned over the years is that as long as the river is flowing at 1200 cfs or less, I can go almost anywhere I want on the river. 750 cfs is ideal. This is the level where even a novice wading fisherman would feel comfortable being in the water.
1500 cfs makes some areas very difficult to access. This is the level where your feet will start to move out from under you if you are out in the current. I've tested this and got into a couple of situations where I thought for sure I was going to get knocked over. Luckily that didn't happen.
When the water is flowing at over 1500 cfs, that is when I'm sticking pretty close to shore. Even here I have to caution guys to be careful. I only go to places that I know like the back of my hand. If an area is behind a big gravel bar and that area is only ankle deep during normal water, then if the river is up 2 feet, I know I won't get in trouble. An area that is normally waist deep would now be impassable and a guarantee that you will get in trouble. So know the river ahead of time.
Hope this helps. Easiest thing to do is go out fishing, come home and print out the graph, that way you can start to get a feel for where the water level was, and what it means for the next time you get out.