Since 1953, precipitation has been recorded at the Walnut Gulch Experimental Watershed in Universal weighing-type gages. Within the protective housing, precipitation is collected in a bucket that rests on a weighing platform and frame, which are suspended from a spring. As precipitation collects in the bucket, the load on the spring is increased, which lowers the platform and frame. The deflection is proportional to the amount of precipitation collected. The movement of the frame is mechanically transmitted to a pen, which marks a graduated revolving chart.
Digital raingages were installed on the Watershed to provide a continuous data stream. 1999 was the first complete year of operation.