How to Measure Flood Stages

The American Meteorological Society defines a flood stage as a fixed, accepted gauge height at which water tops the banks in a flood. The zero stage is usually at or near the streambed. Hydrologists refer to the water levels below the flood stages as stream stages and measure stages in feet and inches using gauges marked in 1/100th or 1/10th foot intervals. Just as a basin has more than one stream stage, it can have more than one flood stage.

Instructions

• 1

  Purchase an appropriate number of stream gauges, available at better agricultural suppliers. If you want to measure the water levels of a body of water by your home, you will only need one. If you want to measure water levels at a number of locations in a body of water on an acreage, you'll need a few. Determine how many by deciding if you want to place them at regular intervals, such as every two acres or at points at which the terrain significantly changes along the water line.

• 2

  Place your stream gauges according to the manufacturer's directions at your pre-determined intervals. Ensure they are sturdily anchored in the streambed so they do not wash away.

• 3

  Take regular measurements of water levels. The U. S. Geological Survey makes its gauge readings every 15 to 60 minutes but, it provides its data to National Weather Service for calculating flood forecasts. You could choose to make only one reading per day but, it needs to be measured at the same time each day and you should not skip days.

• 4

  Record your data. Keep a log of the date, time and height of the water for each gauge. Also, record each time the water body floods at each gauge. If you want to know ahead of time which levels to watch for, contact your city's planning office or the water body's basin commission. These entities often have flood stage maps that illustrate the flood stages for a basin.