Water Currents: Water Harvesting Methods

Water conservation of both surface and groundwater is a key component to increase access to, quantity, and quality of water supplies to meet basic human needs, support economic growth, enhance food security, and maintain ecosystems.

Within USAID water conservation is viewed as a multisectoral challenge that is addressed through water resources management, food security, biodiversity conservation, resilience, climate change, and natural resources management programming. Common methods to conserve water include implementing modern irrigation methods, increasing forest cover, and reusing water/wastewater. This issue focuses on two relatively low-tech, cost-effective water conservation techniques, rainwater and fog harvesting.

Rainwater harvesting methods can improve access to drinking and irrigation water, increase groundwater recharge and reduce stormwater discharges, mitigate urban flooding and the overloading of sewage treatment plants. Fog harvesting is an ancient practice in which water is collected from fog using large pieces of vertical canvas.

RAINWATER HARVESTING 

Country Reports
Lessons from the Field: Rainwater Harvesting in IndiaNational Geographic, May 2019. This article gives an overview of Hiware Bazaar village in India and how the village has successfully used rainwater harvesting to secure water supplies.

Rain Water Harvesting Brings Relief to Four Drought and Flood Prone Districts in Sri LankaDaily FT, July 2019. The USAID–funded water harvesting project of the Lanka Rain Water Harvesting Forum is nearing completion. Its has installed rainwater harvesting (RWH) units that benefit more than 17,000 people, 48 schools, and 10 medical clinics.

Why Doesn’t Every Family Practice Rainwater Harvesting? Factors that Affect the Decision to Adopt Rainwater Harvesting as a Household Water Security Strategy in Central UgandaWater International, November 2018. This article investigates the reasons householders do, and don’t, adopt domestic rainwater harvesting. Factors that emerged as important are the work of intermediary organizations, finance mechanisms, life course dynamics, and land tenure.

A Review of Rainwater Harvesting in Malaysia: Prospects and ChallengesWater, April 2018. Although Malaysia issued rainwater harvesting guidelines in 1999, this study found that its implementation as an alternative water resource is still limited due to its long return on investment and poor public acceptance.

Assessing the Potential for Rooftop Rainwater Harvesting from Large Public InstitutionsInternational Journal of  Environmental Research and Public Health, February 2018. RWH from large institutions in Ethiopia would enable a significant volume of potable water to be transferred to localities critically suffering from water shortage. However, the present study assumed that financial constraints to install large-sized storage tanks pose a possible challenge.

Rainwater Harvesting in Buildings in Brazil: A Literature ReviewWater, April 2018. Topics covered in this review include economic, environmental, and social impacts related to RWH. It also assesses legislation enacted to promote the practice.

Potential of Rainwater Harvesting in Rwanda: A Deep-Dive into Best Management Practices of Rainwater Harvesting Systems in KigaliCentre for Science and Environment, April 2019. This report focuses on urban RWH systems and includes case studies from schools, hotels, and industries in Kigali.

Health/Water Quality Issues
A Global Review of the Microbiological Quality and Potential Health Risks Associated with Roof-Harvested Rainwater TanksNature, March 2019. To provide a summary of microbial contaminants in rainwater tanks and contextual factors, researchers conducted a comprehensive review to analyze the uses of rainwater, factors affecting water quality, concentrations of fecal indicators and pathogens, the attribution of pathogens to host sources using microbial source tracking, and microbial ecology. The study also determined human health risks using epidemiological approaches and quantitative microbial risk assessments and treatment approaches for mitigating risks.

Improving Water Access and Health Through Rainwater Harvesting: Perceptions of an Indigenous Community in Jalisco, MexicoSustainability, September 2019. A survey revealed that the use of RWH systems in this community has increased and that the incidence of diarrheal diseases has decreased significantly.

Arsenic Detected in Rainwater Harvesting Tanks in BoliviaRural Water Supply Network, August 2019. This finding alerted organizations to the risk of rainwater contamination in the region. Tests identified roof dust that flushes into the tanks from the roof catchment as the principal source of arsenic in the rainwater. No arsenic was detected in raw rainwater before it interacted with the roof or tank. The source of the arsenic in the dust is unknown, but widespread mining contamination in the area is likely a contributor.

Antibiotic-Resistant Pathogenic Escherichia Coli Isolated from Rooftop Rainwater-Harvesting Tanks in the Eastern Cape, South AfricaInternational Journal of  Environmental Research and Public Health, May 2018. The results of this study concluded that the use of untreated harvested rainwater for potable purposes may pose a risk of transmission of pathogenic and antimicrobial-resistant E. coli.

Rainwater Harvesting for Smart Health Care FacilitiesPan American Health Organization, May 2019. This technical brief discusses the components of a rainwater harvesting system for health care facilities.

Nonpotable Uses of Rainwater
Rainwater Harvesting for Agricultural Irrigation: An Analysis of Global ResearchWater, June 2019. It is necessary to increase the number of studies on the capacity of RWH systems to cover irrigation needs in different farming contexts, the factors that determine their adoption by farmers, the economic and financial feasibility of their implementation, and their contribution to mitigating global climate change.

An Analysis of the Effectiveness of Two Rainwater Harvesting Systems Located in Central Eastern EuropeWater, March 2019. Researchers analyzed the effectiveness of RWH systems for toilet flushing in academic facilities located in Poland and Slovakia. The study concluded that the use of rainwater for toilet flushing would achieve water savings of 29 percent and 18 percent, respectively, for facilities located in Slovakia and Poland.

Practices and Hydrological Effects of Road Water Harvesting in Northern Ethiopia: Towards Design of Multi-Functional InfrastructuresMomona Ethiopian Journal of Science, October 2019. Results of the study revealed that harvesting water from road catchments is found to have several benefits: increase in shallow groundwater recharge, improvement in soil moisture (up to 90 percent increase), and increase in the availability of surface water in ponds and reservoirs.

Technologies
Infiltration Ponds: Restoring Groundwater ResourcesUSAID Indonesia Urban Water, Sanitation and Hygiene (IUWASH PLUS) Project, April 2019. An innovative intervention developed under the predecessor project IUWASH constructed and installed infiltration ponds to collect rainwater, an effective method to improve groundwater sources.

National Storrmwater Calculator (SWC). U.S. Environmental Protection Agency. The SWC was developed to help support stormwater management objectives and regulatory efforts to reduce runoff through infiltration and retention using green infrastructure practices as low impact development controls. The website also includes a Factsheet and Video.

Smart Phone App to Improve Rainwater Harvesting in AfricaUN Environment Program (UNEP), April 2019. A smart phone app developed by UNEP and the UN Educational, Scientific and Cultural Organization calculates the amount of rainwater that can be harvested from the roof of houses. The app is based on actual meteorological data collected from weather stations across Africa.

Smart Rainwater Management: New Technologies and InnovationIntechOpen, October 2019. This chapter discusses water quality issues in cities and the research advances in handling those issues. Among them it investigates RWH technologies and some of their practical applications.

Implementation of Rainwater Harvesting Systems with a Geomembrane Bag in Honduras and El SalvadorGlobal Water Partnership, February 2019. RWH systems using a geomembrane bag to store rainwater have proven to be a successful technology because of its technical simplicity and wide availability of components, and can be an effective alternative in places where conventional systems are not considered.

FOG HARVESTING 

How Scientists Are Harvesting Fog to Secure the World’s Water SupplyPBS News Hour, July 2019. This news segment highlights how scientists around the world are leveraging familiar scientific principles with modern technology to capture water from the moisture in fog. John Yang reports on these innovative efforts to address the worsening water crisis.

Gender and Community Mainstreaming in Fog Water Collection SystemsWater, October 2018. This paper concludes that fog water collection projects have shown positive outcomes for women and girls through the freeing of time for domestic and educational pursuits, improved health outcomes, and improved perceptions of self and others’ perceptions of women.

Drops of Diplomacy: Questioning the Scale of Hydro-Diplomacy through Fog-HarvestingJournal of Hydrology, July 2018. This paper argues that, by using fog to facilitate collaborative exchange, a nonprofit organization in Morocco is engaging in a form of hydro-diplomacy to lay the groundwork for durable peace, intercultural understanding, and symbiotic growth.

Fog Water Collection: Challenges Beyond TechnologyWater, March 2018. Among the unconventional water resources, the potential to collect water from the air, such as fog harvesting, is by far the most under-explored. Fog water collection is a passive, low maintenance, and sustainable option that can supply fresh drinking water to communities where fog events are common. Because of the relatively simple design of fog collection systems, their operation and maintenance are minimal and the associated cost likewise; although, in certain cases, some financially constrained communities would need initial subsidies.

Fog and Dew as Potable Water Resources: Maximizing Harvesting Potential and Water Quality ConcernsGeoHealth, October 2018. The few studies that report trace metal or biological measurements suggest elevated trace metal concentrations or biological contamination that could be of concern to public health. This article discusses the potential for fog and dew harvesting technologies and the need for trace metal and biological analyses of these waters before use.

Online One Day Masterclass: Fog Collection for Water Management and Sustainable ForestryWater Harvesting Lab, February 2019. Research has shown fog collection, and fog-forest interaction management, is a viable way to fight drought, combat land degradation, and overcome climate change in arid areas. This online course explains the strategies and practicalities of fog collection.