One of the most useful fishing tools I have found that allows me to discover when to go fishing and when to stay home is the USGS Real-time water data website. You can discover the real time flows of streams and rivers across the US via any Internet connection. This information is especially handy when fishing for trout or steelhead and deciding if a stream is to high or to low to fish and will give you an advantage on knowing what flies or types of lures you should have with you.
One of best uses of the USGS website is related to steelhead fishing on the tributaries of the Great Lakes in which water flow and rainfall will make you break you trip. I was planning on going fishing today, however due to the large amounts of rain that hit the Northeast yesterday it flooded out the streams which I could easily see on the gauges of a stream that dumps into elk creek which is monitored by the USGS.
Brandy Run - Elk Creek - This creek dumps into Elk Creek and you can effectively monitor the levels of Elk Creek with this gauge. When it's down Elk Creek is down and when it shoots up due to run off or rain Elk Creek is muddy.
Walnut Creek - This gauge monitors the waters of Walnut Creek upstream from the Manchester hole and you can determine the water level of Walnut Creek to a T with this water gauge.
New York - Lake Erie
Cattaraugus Creek - This is my favorite gauge and one that I look at the most, the Catt is only fishable when the water gauge is between 2.5 fps and below with most anglers seeing the 2.0 as the magic number for the Catt. Cattaraugus Creek is highly volatile to rain and run off so this gauge should always be checked before fishing the Catt in NY.
New York - Lake Ontario
Salmon River at Pineville - This gauge monitors the waters of the Salmon River in NY which is home to large salmon runs in the early fall and large steelhead runs to follow.
Michigan - Lake Michigan Gauges
Pere Marquette River Gauge - The Pere Marquette river gauge in Scottville MI monitors the river and very useful when fishing in MI waters.
Muskegon River- The Muskegon River is a controlled release from a dam however it can fluctuate quickly from day to day depending on how much water is released.
Muskegon River Gauge - The Muskegon River is a controlled flow river in which most fish from a float boat which makes use of this gauge essential to know whether the river is right for a float trip.
These are just a few of the real time water data gauges that I use on a regular basis but anytime I go fishing I consult these gauges to get an idea of how much rain or what type of water I can expect. I check these gauges even if I'm going fishing in a lake just to have an idea if the water is going to be muddy or if the water temp has increased or decreased in the past few days. Many of these gauges have water temp gauges that let you know the water temperature of the water, which is crucial for anglers. So before you go fishing next time consult the USGS water gauges to see if it's worthwhile to go fishing or to stay home and tie flies.