Potential of rooftop rainwater harvesting to meet outdoor water demand in arid regions

Abstract

The feasibility of rooftop rainwater harvesting (RRWH) as an alternative source of water to meet the outdoor water demand in nine states of the U.S. was evaluated using a system dynamics model developed in Systems Thinking, Experimental Learning Laboratory with Animation. The state of Arizona was selected to evaluate the effects of the selected model parameters on the efficacy of RRWH since among the nine states the arid region of Arizona showed the least potential of meeting the outdoor water demand with rain harvested water. The analyses were conducted on a monthly basis across a 10-year projected period from 2015 to 2024. The results showed that RRWH as a potential source of water was highly sensitive to certain model parameters such as the outdoor water demand, the use of desert landscaping, and the percentage of existing houses with RRWH. A significant difference (as high as 37.5%) in rainwater potential was observed between the projected wet and dry climate conditions in Arizona. The analysis of the dynamics of the storage tanks suggested that a 1.0-2.0 m 3 rainwater barrel, on an average, can store approximately 80% of the monthly rainwater generated from the rooftops in Arizona, even across the high seasonal variation. This interactive model can be used as a quick estimator of the amount of water that could be generated, stored, and utilized through RRWH systems in the U.S. under different climate conditions. The findings of such comprehensive analyses may help regional policymakers, especially in arid regions, to develop a sustainable water management infrastructure. Keywords: rooftop rainwater harvesting; rainwater storage tank dynamics; sustainability of outdoor water usage; sustainability of water in arid regions; best management practices in arid regions; variation of rainfall under various climate conditions

Feasibility, seasonality and reliability of rainwater harvesting in buildings of a university in Campina Grande, Paraíba

“…The importance and feasibility of RWH in different arid and semi-arid regions in the world have been found in many studies (Stout et al, 2015;Tamaddun et al, 2018;Abdulla, 2019;Molaei et al, 2019;Toosi et al, 2020;Shokati et al, 2020;Al-Qawasmi, 2021). In the Brazilian semi-arid region, there are also some initiatives in this regard in urban areas (Souza, 2015;Santos & Farias, 2017;Jesus et al, 2019;Silva et al, 2021).…”

Contribution of Rainfall on Rooftop Rainwater Harvesting and Saving on the Slopes of Mt. Elgon, East Africa

“…This study recognises that several studies have been conducted in the arena of rainwater harvesting, for example, the potential of rooftop rainwater harvesting [ 12 , 13 ], the impact of rainwater harvesting on climate change adaptation [ 14 ], increment in water supply [ 15 ], assessing the potential of rainwater harvesting systems in institutions [ 16 ], rainwater harvesting in modern cities [ 17 ], and their performance [ 18 ]. Nonetheless, little attention has been paid to the contribution of deploying domestic rooftop rainwater harvesting systems to store and save water in mountainous landscapes dominated by rural households.…”

Exploring the Sustainable Use Strategy of Scarce Water Resources for Rural Revitalization in Yanchi County from Arid Region of Northwest China

“…Development of rainwater, reclaimed urban greywater and industrial wastewater can increase water supply in Yanchi county. Rainwater collected from rooftops, courtyards and similar compacted or treated surfaces are good substitutes for rural domestic and production water [ 49 , 50 , 51 ]. Rainwater harvesting can alleviate not only water scarcity but also reduce floods in the fragile environment [ 12 ].…”