Rainwater harvesting as a sustainable solution for the production of urban hydroponic crops

Population growth and poor agricultural practices demand an improvement in the efficiency of food production. Urban hydroponic crops represent a potential solution to this challenge. However, the use of drinking water for urban agriculture is not a priority. Consequently, rainwater harvesting can reduce the use of drinking water for other purposes than human consumption. This study evaluated the efficiency of rainwater harvesting for the production of hydroponic crops in an Andean city. We developed a rainwater harvesting model to analyze the efficiency and optimization of two hydroponic production scenarios: (1) domestic production (30 plants) and (2) small-scale commercial production (200 plants). We found an efficiency of 99.71 and 75.79%, for scenarios 1 and 2, respectively. The 75.79% efficiency is given by the presence of low precipitation periods, which in the case of the study area are sporadic. Furthermore, scenario 2 could reach efficiencies of 100% if the roof capture area increases up to 40 m2. Rainwater harvesting in Andean cities, with sustained precipitation throughout the year, is enough to supply water for domestic and small-scale commercial hydroponic production with basic household modifications. We show promising results by combining rainwater harvesting and hydroponic crops for improving urban food and water security.