Developing and Applying a Rooftop Rainwater Harvesting Decision Tool for Impoverished Communities in South Africa

EPA Grant Number: SU834339
Title: Developing and Applying a Rooftop Rainwater Harvesting Decision Tool for Impoverished Communities in South Africa
Investigators: Ward, Andy
Institution: The Ohio State University
EPA Project Officer: Nolt-Helms, Cynthia
Phase: I
Project Period: August 15, 2009 through August 14, 2010
Project Amount: $9,992
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet (2009) RFA Text |  Recipients Lists
Research Category: Pollution Prevention/Sustainable Development , P3 Challenge Area - Agriculture , P3 Challenge Area - Water , P3 Awards , Sustainability


The primary goal of the project is to develop a Decision Support Tool that can be used to determine the economic benefits of and to correctly size a rooftop rainwater harvesting system for impoverished communities in South Africa that is in support of U.S. EPA’s Clean Water Act, Section 104. Currently, about 20% of the world’s population is without a secure supply of potable water; this number exceeds 40% in Africa. In impoverished communities, such as those found throughout South Africa, unemployment is high, the standard of living is low, and there are numerous waterborne diseases and health concerns from standing water and fly infestations. Often, these impoverished people do not have the resources to satisfy basic bathing and sanitation needs. By developing this Decision Support Tool and subsequent rainwater harvesting systems that can be adapted all over the world, we hope to ameliorate some of these issues. At the individual household and community scales a range of rooftop harvesting systems such as rain barrels and cisterns have been developed. However, rain barrels often are not sized according to the available roof surface area, collect only a small fraction of the available precipitation, and an appropriate cost-benefit analysis normally is not performed. Therefore, while rooftop rainwater harvesting systems might be considered by some as off-the-shelf technologies the Decision Support Tool we propose developing is very innovative as it will: (1) evaluate design thresholds associated with alternative end uses, climatic factors, and infrastructure constraints (i.e., rooftop size and height above the ground, topography, space availability, etc.); and (2) consider socio-economic factors and government policy (i.e., security, economic benefits, health and living benefits, needs to conserve water, availability of subsidies, social acceptance, etc.).


In the 2008-2009 academic year, an undergraduate team developed a prototype for a Microsoft Excel based Decision Support Tool for sizing and determining the costs of the collection, storage and end use components of a rooftop rainwater harvesting system for application in South Africa. The project will: (1) us the Decision Support Tool to design a rooftop rainwater harvesting system for a housing unit in the iEEECO™ Village located at Witsand, Atlantis, South Africa; (2) visit Cape Town, South Africa to consult with the Witsand iEEECO™ Village project team and other local stakeholders and to then implement the installation of the rooftop harvesting system and a vegetable garden; (3) establish a mechanism for evaluating the performance of the rooftop rainwater harvesting system; (3) have discussions with stakeholders on factors that should be incorporated in the Decision Support Tool; (4) identify local experts and databases that will be useful in refining the development of the Decision Support Tool that will include an Expert System; and (5) as an outcome of this work, and the implementation activities, enhance the Decision Support Tool. In addition, data will be obtained on a rainwater harvesting system in Columbus, Ohio. Anticipated enhancements include an enhanced use of climatic data, the inclusion of algorithms to account for deficit and excess soil water influences on crop growth and further work on currency and unit conversions to make the software more global. Efforts will also be made to evaluate water quantity and quality benefits.

Expected Results:

The main outputs will be the Decision Support Tool and the design, installation and evaluation of a demonstration harvesting system that will be installed at the Witsand iEEECO™ Village Project Site in Atlantis, South Africa. The iEEECO™ Village project is underway and we have an agreement with the City Project Manager, The Community Organization and the Lead Consult (PEER Africa (Pty) Ltd.) to implement the project. The main outcomes will include practical knowledge on how to establish sustainable rainwater harvesting systems that enhance water resources and the quality of life for impoverished communities in South Africa and, in the long term, other regions of the world.

Supplemental Keywords:

economic model, water harvesting, rain barrel, developing country, water pollution,

Progress and Final Reports:

  • Final