Grantee Research Project Results
Final Report: SQWater: Atmospheric Water Resources in the Slums of Lima, Peru
EPA Grant Number: SU835312Title: SQWater: Atmospheric Water Resources in the Slums of Lima, Peru
Investigators: Spencer, Benjamin R. , Wang, Hsien Ai , Giampietro, Vera Eve , Hsu, Shu- Kuei , Yiu, Kei Sing , Rockquemore, Angelica , Anderson, Betsy , Alford, Brooke , James, Cayce , Dolbeare, Corey , Ramirez, Daniel , Hoffman, Daniel , Bush, Erica , Nakajo, Gayna , Daniel, Ginger , Pritchitt, Hillary , Pagan, Jonathan , Lewis, Jordan , Kuldkepp, Kaie , Bogle, Kevin , Andrews, Leann , Takieddine, Malda , Shwindeller, Michael , Hai, Orona , Cromwell, Peter , Syvertsen, Philip , Feld, Shara , Wissmer., Sunni , Bolton, Susan , Hanson, Taj , Kuo, Winnie , Lin, Yu-Ting
Institution: University of Washington
EPA Project Officer: Hahn, Intaek
Phase: I
Project Period: August 15, 2012 through August 14, 2013
Project Amount: $14,423
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet (2012) RFA Text | Recipients Lists
Research Category: P3 Challenge Area - Sustainable and Healthy Communities , P3 Challenge Area - Safe and Sustainable Water Resources , Pollution Prevention/Sustainable Development , P3 Awards , Sustainable and Healthy Communities
Objective:
More than 1 billion people, close to 20% of the world’s population, live in urban squatter communities (slums). By the year 2050, this number will approach 3 billion. In Lima, Peru more than a third of the city’s 9 million occupants live in slums, many without reliable access to clean water, adequate nutrition and public green space. Within as little as a decade, the city’s primary water supply, Andean glaciers below 5500 meters, will melt as a result of climate change and the city’s already inadequate water networks will become increasingly dysfunctional. Although Lima receives only 10mm of rain per year, it is shrouded in a blanket of moist fog from June until December. Our project, SQWater focuses on the design, development and evaluation of fog water harvesting technologies that provide water for irrigation or domestic use, help Lima’s slum communities adapt to increasing water scarcity, preserve the integrity the city’s remaining water resources and reduce air and water pollution due to water production, distribution and use.
The project is based both in Lomas de Zapallal (LdZ), a slum in northern Lima and the University of Washington (UW). It leverages existing UW service learning courses and builds upon a long standing relationship between the UW, the Universidad Nacional Mayor de San Marcos (UNMSM) and the community of LdZ. Following an initial period of research and participatory design during a study abroad program in LdZ, students returned to the UW to design, build, test and refine prototypes for a fog harvesting system, optimized for Lima’s winter climate. They explored fog collector materials and forms and experimented briefly with acoustic fog precipitation as a means of increasing fog collection yields. They then integrated the fog harvesting system into the design of public green spaces and vegetable gardens that provide LdZ residents with a place to relax and play, augment habitat for local species, help clean Lima’s pollution laden air, serve as source of nutrition and generate income.
Summary/Accomplishments (Outputs/Outcomes):
Building upon an UW Exploration Seminar held in Lima in August/September of 2012 (non EPA funds), a multidisciplinary group of students met in 3 different classes over 2 quarters. The fall class focused on learning about the physics of fog and the types of systems that have been designed to collect fog. This formed a theoretical basis for the 2 classes that met in winter quarter. Again, an interdisciplinary group of students met and began to discuss and design components for capturing, storing and distributing fog water. Early in the quarter, student teams each developed unique ideas for complete fog collection systems and designed and built a hoop house for fog testing. After a formal mid-term review with professionals from on and off campus, teams were rearranged into groups that focused on a single component of the system. Teams were assigned to design, develop and test ideas for fog collection, water distribution for irrigation, vegetative fog and dew collection and overall site design.
Fog Collection: After numerous test runs on various materials and configurations, 3-D turf reinforcement mats (TRM) were identified as a very promising alternative material to the traditional shade cloth that has been used for 30 years. These products are widely available globally and have good theoretical properties such as a thin ribbon size and lots of surface area without sacrificing porosity. A few different configurations were also tested with the most promising being a sail design and a shower curtain design. The sail has many advantages including: (a) structural efficiency – material reductions by using only one pole and three stays, (b) maintenance ease – easy to tension and lower for maintenance, (c) adaptability to changing wind conditions – can easily rotate to face the wind, (d) integration to existing infrastructure – can easily add to the side of a regular SFC, (e) possibility for dispersal – easy to reduce scale, and distribute to point of irrigation to reduce water distribution costs. The shower curtain has an increased collection area due to pleats yet maintains the same footprint as traditional collectors.
Water Storage: Storage of collected water from any system for use when no water is available has always been complex and often costly problem. Through researching precedents, the team discovered origami water balloons, folded bits of paper that can hold water long enough to throw. This team tested a variety of materials and settled on 16 ml plastic as the ideal material for folding, holding water and scaling up. A variety of adhesives and duct tape were tested to hold folds in place. Available locally, crown bolt neoprene valves were chosen as inlet and outlet fittings. The origami water storage tank’s estimated cost is $10 in Peru. This compares to approximate $100-150 cost for a manufactured water tank with similar capacity.
Water Distribution: Although fog typically has been used for domestic drinking purposes, the team focused on improved irrigation systems. Of course, the water can be used for whatever purpose meets the community’s needs. Globally over 70% of all water withdrawals are for agriculture so savings in this arena are critical. Using materials from the local waste stream, an irrigation system was tested and designed that uses injection model screw caps and waste soda bottles. The bottle screw cap T- fitting is injection molded using recycled plastic, through a process developed at the UW. The T-ends can be sized to fit regular hoses of various diameters. Wicks of various materials were tested in dry sand for a 24 hour period. The best results came from attaching a wick at the top of the bottle. Wick material (cotton, polyester, nylon) can be varied to control the wicking rate. The soda bottle and wick configuration does not suffer from the clogging issues that plague may subsurface drip systems and limits surface evaporation by delivering water directly to the root zone.
Vegetative Fog Collection: While fog collection has been practiced by humans for the last 30 years, vegetation has collected fog for millennia. Building upon this knowledge, the team experimented with a variety of vegetation types found in, or similar to vegetation found in Lima, to assess their fog collection capacity. Results showed that trees with needles such as the she-oak (Casuarina spp.) performed best as fog collectors. The team also developed a vegetative fog collection cone that encircles the trunk of a tree, captures a portion of the tree’s fog drip and directs it into storage for later use in dry season irrigation, agriculture, as a source of drinking water or for household tasks. The cones are sized to allow the drip from outer foliage to reach a trees root zone and assure that it gets the water it needs to grow. Cost effective, they are easily constructed from a single sheet of plastic. During the dry season, the cones can operate independently as dew collectors, providing a supplementary source of irrigation when fog is not available.
Site Design: Water systems are often buried underground and hidden from view. They lack presence in the public realm, remain segregated from daily experience and are taken for granted. The team saw this as missed opportunity. They sought to integrate the fog collection/water system into the conceptual design of public space and give it a tangible presence. In doing so, they hoped to foster awareness of water and an ethic of sustainable water use. The site design draws extensively on the participatory input of LdZ community members and consists of three potential elements; ecological restoration zone including a fog collection farm and a series of community gardens, the redesign of an existing informal cemetery serving all of LdZ and a small public park in LdZ’s Eliseo Collazos neighborhood. Fog water provides irrigation for trees, shrubs and agriculture, bringing new life to LdZ’s impoverished neighborhoods and helping to restore Lima’s long since denuded ‘lomas’, dry forest ecosystems. The site design represents a long term community vision that will unfold over many years. The team hopes to undertake a green space intervention representing a small portion of the larger site design during Phase II of the EPA P3 grant as a catalyst for future development.
Conclusions:
By seeking improvements in all components of a fog collection system, a holistic and integrated design was created. The SQWater system addresses the planet by capturing a relatively clean and renewable atmospheric water source that can supplement scarce water resources for a number of uses including reforestation of damaged ecosystems. It addresses people by explicitly including the target community in design and purpose of the project from the start. It addresses prosperity by offering a way to deliver water that is clean, can be used for urban farming to improve nutrition and generate income, to irrigate parks and reforestation projects that improve human health and well-being and can provide point of use water at the household level for drinking and washing.
Supplemental Keywords:
Fog collection, fog nets, atmospheric water, slum infrastructure, arid communities, water supply, drip irrigation, low cost water storageRelevant Websites:
The Informal Urban Communities Initiative Exit
Facebook: SQWater EPA Exit
UW project seeks to harvest fog for irrigation Exit
UW students create, harvest fog in campus ‘hoop house’ Exit
The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.