Development of Evapotranspiration-Based Irrigation System Using Hargreaves-Samani Equation for Public Park Application

Different methods in water saving are applied to maintain the landscapes and reduce the amount of water needed to be irrigated in public parks. Scheduled watering is the most common type of method used by public parks, in which estimating the amount of water leads to over or under irrigation. Irrigation systems that uses evapotranspiration as a parameter in controlling the amount of water to irrigate on public parks are not found in the Philippines. Evapotranspiration is the rate of water lost from plants and soil through evaporation and transpiration within a specific area. This study focuses on the development of a device that would be used for the monitoring of evapotranspiration using the Hargreaves-Samani Equation. This would include the calibration of sensors and development of device used such as the DHT22 Humidity and Temperature sensor, Water Flow sensors and Tipping Bucket Rain Gauge. Furthermore, a Stevenson screen is created to provide the sensors protection from harsh weather conditions and provide proper ventilation. After testing the prototype, the results obtained from the sensors provided an average percent difference of less than 5%, indicating that the prototype is functioning properly.