An interfaced hydrologic data acquisition-processing system has been installed at the University of Arizona. A forested mountain watershed and a desert watershed area within a 50 kilometer radius of the campus are instrumented for measuring, a variety of hydrologic and climatic variable. Measurement data are both multiplexed over the Bell Telephone system and transmitted by radio to a campus laboratory. Measurements on the desert watershed may be programmed in any sequence and sampling rate varied from seconds to 24-hour intervals automatically or according to the rate at which input signals may change. Offers a unique means of teaching principles of hydrologic processes, methods of data acquisition and procedures in hydrologic analyses.`.