Final Report: Rain or Shine: Rainwater Harvesting Systems for Dependable, Safe Drinking Water in Rural GuatemalaEPA Grant Number: SU835508
Title: Rain or Shine: Rainwater Harvesting Systems for Dependable, Safe Drinking Water in Rural Guatemala
Investigators: Elgert, Laureen , Austin, Pat , Mensing, Michele , Moutinho, Thomas , Picchione, Katie , Washburn, Tom
Institution: Worcester Polytechnic Institute
EPA Project Officer: Levinson, Barbara
Project Period: August 15, 2013 through August 14, 2014
Project Amount: $14,965
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet (2013) RFA Text | Recipients Lists
Research Category: P3 Challenge Area - Water , Pollution Prevention/Sustainable Development , P3 Awards , Sustainability
The purpose of our project was to design and pilot-test a household rainwater harvesting (RWH) system to improve water security in rural Guatemala. Water security involves three dimensions: sufficient quantity to satisfy basic needs as locally defined; quality that is appropriate for different use (including potable water for drinking and cooking); and access to water by all households. In light of these three dimensions, our project objectives were:
We researched and designed RWH systems in two households in Guach Tuq, focusing on: system efficiency to maximize quantity of water collected; design features that improved water quality; and, local involvement in design and construction to promote homeowners’ capacity to maintain the system over the long term, thereby assuring continued access. In addition to Rain or shine: Rainwater harvesting systems for dependable, safe drinking water in rural Guatemala implementing RWH systems, we undertook extensive testing to compare the quality of water originating at different sources, and to assess the quality of water from the implemented systems. Finally, we conducted in-depth interviews with twelve households to gain a better understanding of how RWH systems could impact the social, economic and physical factors in household access to water.
- Average per person water consumption is ~44 liters/day
- Water storage capacity was increased to satisfy basic household needs
Through interviews we established that the average quantity of water required by each person in a household is 44 liters per day. Using a model previously developed by colleagues that incorporates variables such as roof area, system efficiency, average rainfall rates, and number of individuals in the household, the amount of storage necessary to provide the quantity needed was calculated. Through Phase I implementation, storage capacity was increased to meet household requirements at both homes.
- Three design features have improved water quality: netting, first flush and overflow
- Portable Microbiology Lab (PML) is a means of water quality testing in challenging environments
- Fewer bacteria and no E. coli detected in new tanks, but detected in other samples
We found three design features to positively impact water quality and to be locally feasible and implementable. Netting secured over system openings filtered out leaves and other debris from entering the storage tank. A first flush system was designed to divert sufficient initial rainwater away from the tank in order to rinse potential contaminants from system surfaces before water collection in the tank. The water from the first flush is not ‘wasted’ but remains available for uses other than drinking and cooking. An overflow system that takes water from the bottom of the tank (rather than the top) promotes circulation of the tank water and expulsion of old, rather than fresh, water. We established that PML is a feasible way of testing water quality in rural, developing world contexts. The bacteria test can be incubated by ‘wearing’ it under clothing, and provides a good visual result so that it can be used to increase awareness of water quality in the community. The tests we conducted showed that water from the RWH systems we implemented had lower bacterial counts when compared to both existing RWH tanks and the natural spring source that many people depend upon extensively. One reason for the difference in bacterial counts may be the age of the existing tanks, but proper design is also a factor.
- Individual RWH systems overcome geographical and social factors that reduce local access to clean water
- Local capacity to repair, maintain and adapt systems will promote ongoing access
- System cost is a significant barrier to universal access when scaling up RWH implementation regionally
During interviews, important factors in water security included household location in the community (ranging from ¼-1 mile), competition with other households, and long waits at the natural spring source, particularly in the dry season. Bringing water to individual households addresses these factors by facilitating less time-intensive and more equitable access to water. Working closely with local people in design, re-design, and construction has built local capacity to maintain and adapt RWH systems according to local needs. Many of our original design features have been adapted to use locally available materials, such as replacing plastic gutter clips with wooden supports, and repairing and extending (as opposed to replacing) existing rooftops. The RWH systems have been implemented at a cost of around $900 each, the bulk of which reflects the cost of the water storage tanks. This high cost remains a barrier to access for most households in Guach Tuq and surrounding communities.
Rainwater harvesting is an appropriate technology which has improved quantity, quality and access dimensions of water security in two households, and has the potential to do so on a wider scale. Benefits to people, prosperity and the planet have been realized in Phase I. People have greater access to water at their own homes and save between two and six hours daily by not having to walk to the spring and transport water back to their homes. The RWH systems also provide cleaner water in comparison to the spring, and it is reasonable to expect that this will result in a decline of waterborne diseases over time. RWH systems promote prosperity by allowing people to use time saved to pursue income generating activities, or to spend more time in studies and skill development. Once the systems are implemented using local materials, local capacity to maintain them will reduce dependence on outsiders to undertake costly repairs. Local people who have been working on implementation and construction also develop skills that they may apply to income earning opportunities in the future. The planet also benefits from these RWH systems by reducing the draw from the local spring (and therefore pollution of the spring that is a byproduct of use) and using considerably less energy than other water delivery mechanisms.
However, in local terms the existing system design remains expensive. The system needs to be constructed more affordably, with local materials, if it is to be more widely accessible. Furthermore, implementation is dependent on the presence of our team. We need to strengthen local capacity for implementation by continuing to work with stakeholders at multiple scales, such as the community-based water committee, local NGOs and the municipal government. Several strategies have been integral to the success of Phase I and are recognized by our team as vital for ongoing work in scaling up RWH systems in rural Guatemala. First, our work has been characterized by collaboration, mutual learning and adaptive design. We have worked with local people, the end users of the RWH systems, from design to construction. They have learned from us about the principles of RWH and water quality. We have learned from them about construction techniques and local materials. This has led to adapting the original RWH system design to accommodate local contingencies and be more appropriate, usable and sustainable at the local level. Secondly, we have developed strong relationships and close partnerships with local individuals and institutions. We have had strong symbolic and material support in Phase I from CeCEP, a regional NGO; the Mayor of the Municipality of San Cristobal; and the Water Committee of Guach Tuq. Each of these entities has provided indispensable support and resources at various stages of Phase I. Thirdly, our diverse team has approached this project as an interdisciplinary endeavor. This has enabled us to understand the issue of water security broadly, and as a problem that entails social, economic and technical assessments and solutions.