Assessing the Feasibility of Rooftop Rainwater Harvesting for Food Production in Northwestern Arizona on the Hualapai Indian Reservation

Abstract

With the uncertainties of climate change and the persistence of droughts in the Southwestern US, finding additional renewable water resources is crucial to ensure safe drinking water and attain food security in rural and tribal communities. Rainwater harvesting (RWH), the practice of centralizing, collecting, and storing rainwater for later use, has the potential to help alleviate some water stresses in these communities. Although RWH is not a new concept, it has not been widely practiced in arid and semi-arid environments in the United States. This study assessed the feasibility of rooftop RHW at a small scale, in Peach Springs, Arizona, on the Hualapai Indian Reservation. Working alongside the Federally Recognized Tribal Extension Program (FRTEP) agent for the Hualapai Tribe, this study considered RWH from four prospective buildings to supplement irrigation practices for food production. Due to high standard deviation and coefficient of variation values, annual precipitation amounts were classified into normal, dry, and wet years to assess variability over the last 40 water years. An average total of ~29,285 L could be collected from one of the buildings considered for RWH during the growing season of April to September during a classified normal year. The Food and Agriculture Organization’s (FAO) AquaCrop model was used to determine the area that can be cultivated with four staple crops, maize, tomatoes, dry beans, and sunflowers, which are currently being grown in the community garden, solely using the captured rainwater. Cultivable areas range from 8.7 m2 to 71 m2 depending on the catchment size, crop, and classified precipitation year—a wet, dry, or normal precipitation year. A total of 81.2 kg of dry corn could be harvested during a normal precipitation year, solely using the collected rainwater from one of the buildings.