Knowing the range of USGS streamflow data for the creeks and rivers you fish regularly (or for the first time) is an essential piece of trip planning information.
Combined with the empirical ‘data’ you collect on each outing, current streamflow conditions provide you with information to plan your approach, tactics, and gear for the day and may be the primary factor in deciding whether to stay at home or to fish a stream in a different watershed based upon favorable gage data.
We’ve provided direct links to each state’s real-time data below. You’ll also find an explanation of the data and how to use it for your next trip.
Links to USGS Streamflow Data By State
Click on the state you are interested in below and you will be taken to the statewide Daily Streamflow Table.
The gaging stations will be grouped by river basin but the drop down menu at the top of the page gives you the option to group the stations by county. Scroll down the list to find your stream using either the station name or number.
Daily Streamflow Tables
What is Streamflow Data?
The USGS, under the National Streamflow Information Program, publishes streamflow data collected at gaging stations on rivers and creeks throughout the United States, including Alaska.
Easy to use tabular information and graphs provide current and historical readings for stream discharge (also known as streamflow) measured in cubic feet per second and stream height above the gage zero point (also known as stage). Depending on the gaging station, water temperature data is often available and sometimes you’ll find other water quality indicators such as pH, turbidity, and dissolved oxygen.
USGS streamflow gages are programmed to record in-stream conditions at regular intervals and then send that data to the USGS via satellite. Most gages today take measurements every 15 minutes and then transmit the data every 1 to 4 hours, but this depends on the particular stream and conditions. During floods the USGS may program critical stream gages to operate at shorter intervals.
Federal, state, and local governments use USGS streamflow data to manage and monitor the nation’s water supply. Specific uses include designing bridges and reservoirs, measuring water quality, assessing the impact of flooding and droughts, and understanding the effects of climate and land use changes on the water supply.
How Does Streamflow Information Benefit Fishermen?
While USGS streamflow data is an important tool for government, it’s also highly useful for recreational purposes. Anglers can use discharge, stage, and temperature data to assess water conditions before leaving home.
Current streamflow (discharge) is a measure of the volume of water passing the gaging station in a given period of time. It helps you decide whether a stream can be waded safely and productively or, if you plan to float, whether water levels are high enough to keep your boat off the rocks.
Becoming familiar with optimum flows for wading, floating, nymphing and fishing banks, pools, and riffles in your favorite streams is a way of hedging your bets for a good day on the water. This takes a bit of ‘course knowledge’ achieved by hitting the water at different times throughout the season – but current streamflow data can also be interpolated for first-time trips. Gage data is available for a week or longer so you can see water level trends.
If you search for your specific stream in the statewide USGS streamflow data table, you’ll have the most current discharge value. Select the gage station number for your stream and you’ll be taken to a new page with a graph of discharge data for the last 7 days. The graph can be customized to show historical data for up to 120 days.
Basically, peaks in the graph represent recent rainfall (or if it’s a tailwater, discharge from a dam) and valleys represent periods of little rain or runoff.
Periods of high flow usually mean the stream is difficult to wade, fish are more spread out, and the water is off-color, making it hard to spot fish. Periods of low flow often mean that water temperatures are higher, the fish are stressed and not feeding as often, and the water is clear, making it easier for fish to see you.
Gage height (stage) is more abstract than discharge because it measures just a single point on the stream, but it tells you something if you know it’s relevance to the stream bed and how it holds water in its banks.
I rely on this data less than discharge as it doesn’t represent the entire stream, but it can be a good indicator of whether the water is wadeable or even too low, which could mean higher water temperatures and stressed fish.
If you search for your specific stream in the statewide USGS streamflow data table, you’ll have the most current gage height value. Select the gage station number for your stream and you’ll be taken to a new page with a graph of gage height data for the last 7 days. The graph can be customized to show historical data for up to 120 days.
Temperature at the gage can also be used as an indicator of general stream temperature which factors into fish feeding habits and insect hatches.
Spring time temperatures are typically low and rise in the short warming periods of the day. This can be seen as spikes on the temperature graph – correlate this to the time of day and you will understand why a lot of experienced fly anglers sleep in and fish the afternoons.
I tend to use this information early in the season and as the summer wears on, as these times usually represents the extremes of the season in our home waters. That said, as water temperatures warm up in the spring and hit certain ranges consistently, it becomes easier to predict known hatches with confidence.
For example, in Virginia’s Appalachian Mountain streams, we know decent blue winged olive (baetis) mayfly hatches typically won’t happen until water temperatures remain over 40 degrees — 48 degree water at the gage and overcast skies in the forecast and I’m going fishing!