What test is used to determine distribution uniformity?

• A. Catch can test
• B. Soil moisture test
• C. Calibration of sprinkler heads
• D. Measuring rainfall

Answer: (A)

The test used to determine distribution uniformity is the catch can test. In this method, you place several small containers across the area covered by the sprinkler zone, run the irrigation for a set time, and then measure how much water each can collected. By comparing the depths in all the cans, you can quantify how evenly water is being applied across the area. If the amounts vary a lot from can to can, the distribution is uneven; if the depths are similar, the distribution is more uniform. This test directly provides a measure of distribution uniformity and is a standard approach in irrigation auditing to identify where adjustments are needed, such as changing nozzle types, spacing, pressure, or run time. The other options don’t measure how evenly water is distributed across the landscape: soil moisture tests show water content in the soil, calibrating sprinkler heads is about ensuring individual nozzles deliver their rated amount but is not a direct test of uniformity, and measuring rainfall captures precipitation, not the sprinkler’s distribution pattern.