Optimizing the Automatic Release of Water for Lawn Irrigation with Household Rainwater Harvesting

Abstract

The two key precipitation trends in Massachusetts are higher-intensity storms and longer dry periods between storms, resulting in both higher flooding risks and greater drought stresses. Widespread rainwater harvesting on the household scale can alleviate both of these issues, by capturing significant amounts of rainfall and serving as a supplementary water source for lawn irrigation. As such, an engineering solution is needed to encourage the widespread use of rainwater harvesting. This project involves the design, implementation, testing, and evaluation of an algorithm that controls the automatic release of water from a lawn irrigation system that integrates a household’s piped, treated water supply with the household’s rainwater harvesting supply. This algorithm utilizes historical and forecasted weather data from OpenWeatherMap APIs to increase water-use efficiency. 90 simulations were run for each of 4 locations in Massachusetts using weather data from the past 10 years and various combinations of lawn size and rainwater harvesting tank size at a household. While results highlight the complexity of making lawn irrigation more efficient, they also suggest potential cost savings for consumers on the order of $1,000 dollars per household per year. The relatively simple algorithm developed in this project serves as a starting point for the improvement of lawn irrigation technology and can be expanded upon for added precision, efficiency, and cost savings.