Buildings & Grounds Maintenance

Every day, rain or shine, the Grounds Department weather station, located near the Environmental Safety Facility, telephones a weather report to the Grounds Department office at Bonair Siding. This weather station is a component of the Department's irrigation central control system. The weather data is processed by the central computer, a PC in the Grounds Office, which calculates sprinkler run times based on the daily ET (Evapotranspiration). The central computer then communicates the newly calculated irrigation schedules to the field controllers.

	Weather station sends data to PC in Grounds Office daily		PC automatically computes water needs based on daily weather data.		PC sends revised schedules to field controllers and automatically runs the sprinklers.

Evapotranspiration is a measure of water lost both by evaporation from the soil and by transpiration from plant tissues, and provides a good indication of how much water needs to be applied by irrigation when rainfall is insufficient. Measured in inches per day, ET is calculated based on temperature, solar radiation, rainfall, humidity and wind measurements reported from the weather station. The daily reports from the weather station enable daily adjustment of schedules in all the system controllers, something that would not be possible manually. This can result in significant water savings; for example, a 1996 study of the Oval Lawn indicated that use of Maxicom with ET based scheduling resulted in a 27% water savings.

In addition to irrigation scheduling, we use weather station data for other applications. We calculate degree days for use in our Integrated Pest Management (IPM) programs, and we compute Chill Hours each year for use in plant selection.