Understanding River Levels is crucial to ensuring a safe paddling trip. Water levels that are either too high or too low will make a trip unpleasant (at best) or even dangerous (at worst). The USGS (United States Geological Survey) has many excellent web-sites that post River Levels for literally hundreds of rivers and streams in the United States. The USGS site that has River Levels for the state of Kentucky can be found on our Related Links page. Once you find the reading for the river you intend to paddle, you will need to learn what the numbers mean. There are two numbers on the USGS site that are of interest to paddlers - ‘gauge’ and ‘CFS’. These are two different way of measuring River Levels.

The simplest way to measure River Levels is to measure the depth of the river at a given point (a ‘gauge’ reading in USGS terms). This is how most towns on rivers measure flood stage. Generally, a bridge support has a ruler painted on it and is used a reference. The town folk know that when the river is at say 20 feet, it is normal and at 30 feet the river is considered at flood stage. A town just upstream will probably have a different number that they consider normal and flood stage. Measuring the depth of a river works well when you always measure at the same point, but is of little use in relating the information either upstream or downstream; or if you want to add the volumes of water at two tributaries to calculate the flows of the main stream.

A more general (though more difficult to calculate) approach is to look at the volume of water passing a given point. This is typically measures in Cubic Feet per Second (CFS). CFS measurements are highly calibrated and require significant calculations and regular adjustments. This measurement calculates how many cubic feet of water (1 cubic foot is the amount of water in a 1-foot by 1-foot by 1-foot cube – a cubic foot) pass a line across the river in one second. Typical flow rates can be 1 or 2 CFS on a small creek or several hundred thousand on the Ohio or Mississippi Rivers. While CFS measurements are a bit more difficult to understand, they prove invaluable when you want to piece together information about 2 tributaries that form a river that you want to paddle. If there is CFS reading on each tributary, then all you have to do is add these CFS values and you have a very good approximation of the CFS rating of the main river. With gauge readings described in the previous paragraph, the depth of the river at one point added to the depth of the river at another point has no meaning.

So, now that you understand how the numbers work, what does that mean for your paddling trip? Only through a combination of experience, research and advice will you know what a given river looks like at a given CFS rating. Remember that 1,000 CFS on one river may be a great level, while 1,000 CFS on another river might be a very dangerous adventure. Many books and web-sites (listed in our Related Links page) will have either gauge or CFS guidelines. In addition the outfitters listed in the Kentucky Outfitters page are an excellent source of information on their respective rivers.