Pre-Incan Infrastructure for a Water Secure Future
Summary
Amunas, pre-Incan water-harvesting structures typically used in the Peruvian Andes, could help safeguard Lima against a water-insecure future.
Lima, the world's second-largest desert city, relies on limited seasonal surface water, alluvial aquifers, and inter-basin transfers to provide water to its over 10 million inhabitants ( Hommes & Boelens, 2017; Lerner et al., 1982; Mark, 2015; Ritter, 2018). The city is rapidly expanding, and its population is booming- factors that additionally complicate the megacity's future water security. Further, Lima's water supply is highly variable, which makes ensuring consistent water supply in the megacity a challenge. In the dry season (May to November), droughts are common and river flows are low; in the rainy season (December to March), river levels spike significantly (Gammie, de Bievre & Guevara, 2015). As such, Lima typically experiences large water deficits during its dry season and water surpluses during its rainy season.
Intervention
To address water scarcity, SUNASS (Superintendencia Nacional de Servicios y Saneamiento, Peru's national water regulator) incentivized and supported public water service providers to seek out nature-based solutions to complement the standard engineering solutions utilities employed to enhance water security (Forest Trends, 2020). The national government passed the Compensation Mechanisms for Ecosystem Services Law (2014) to serve as a legal framework and to define permissible nature-based interventions (Forest Trends, 2020). Furthermore, SUNASS regulated a special water tariff to fund these nature-based solutions. Lima's water utility, SEDAPAL (Servicio de Agua Potable y Alcantarillado de Lima), committed to deploying nature-based interventions to enhance its water supply (Forest Trends, 2020).
Amunas, pre-Incan water-harvesting structures typically used in the Peruvian Andes, act as a natural sponge, capturing excess stormwater in the rainy season and redirecting it into the mountain where water is stored, thereby making it readily available during the dry season (Forest Trends, 2020; Mark, 2020; Ochoa-Tocachi et al., 2019). Amunas are stone canals that siphon water from high altitude streams during periods of heavy rainfall (i.e., during the rainy season) and funnel it into the mountain where it filters down through the rocks over the course of months, ultimately emerging from springs during the dry season (Zwick, 2015). SEDAPAL is restoring these canals (and constructing new ones) throughout the Andes to increase the volume of water made available to Lima during the dry season. Presently, one of the last, intact amunas remains in the Huamantanga community (Province of Canta), at an elevation of 3,300 m in the center of the Peruvian Andes (Ochoa-Tocachi et al., 2019). The Huamantanga amuna was used as a model to study the potential effects the amuna system could have on Lima's water security (Forest Trends, 2020).
Along with defining permissible nature-based interventions and serving as the legal basis for nature-based interventions (2), the 2014 Compensation Mechanisms for Ecosystem Services law placed special emphasis on the integration of scientific and indigenous knowledge. As a result, many of SEDAPAL's nature-based interventions, including the amunas , stem from indigenous practices that have been used throughout the Andes for centuries (Forest Trends, 2020).
In 2015, SEDAPAL approved the largest financial commitment for green infrastructure investment of any country in Latin America, announcing a $112 million investment in green infrastructure projects in and around Lima (Kenny, 2015). The $112 million investment is to be secured from municipal water services revenue and amounts to 5% of the total monthly water fees that SEDAPAL regularly collects from water users in the megacity (Kenny, 2015). The investment is intended to go towards programs designed to help the Andes adapt to climate change and improve water quality (Kenny, 2015). Of this, $26 million has been committed to "green infrastructure" programs specifically, including the restoration and construction of amunas (Kenny, 2015). A cost-curve analysis (carried out by Forest Trends and Peruvian NGO CONDESAN) indicated that the amunas' restoration would likely provide the greatest impact in terms of water security at the lowest cost (when compared with all other nature-based solutions implemented in the program) (Gammie, de Bievre & Guevara, 2015).
Challenges
The amunas project in Lima may face challenges related to the scale and complexity of restoring ancient infrastructure in remote, high-altitude areas. The physical condition of the existing amunas may require significant repairs, and constructing new ones could be costly and time-consuming. Additionally, the success of the project depends on maintaining consistent rainfall patterns and ensuring that the system is integrated effectively into Lima's modern water management infrastructure. Climate change and increasing urbanization could further strain the availability of water resources, complicating the project's long-term sustainability.
Outcomes
Modeling (based on the Huamantanga amunas) indicates that the amuna infiltration system can increase the volume of water available to Lima during the dry season by an average of 7.5% per year and up to 33% during the first dry months (Forest Trends, 2020). Ultimately, the restoration of pre-Incan amunas is a cost-effective nature-based solution that could significantly increase Lima's water supply.
References
Pre-Incan Infrastructure for a Water Secure Future
Summary
Amunas, pre-Incan water-harvesting structures typically used in the Peruvian Andes, could help safeguard Lima against a water-insecure future.
Lima, the world's second-largest desert city, relies on limited seasonal surface water, alluvial aquifers, and inter-basin transfers to provide water to its over 10 million inhabitants ( Hommes & Boelens, 2017; Lerner et al., 1982; Mark, 2015; Ritter, 2018). The city is rapidly expanding, and its population is booming- factors that additionally complicate the megacity's future water security. Further, Lima's water supply is highly variable, which makes ensuring consistent water supply in the megacity a challenge. In the dry season (May to November), droughts are common and river flows are low; in the rainy season (December to March), river levels spike significantly (Gammie, de Bievre & Guevara, 2015). As such, Lima typically experiences large water deficits during its dry season and water surpluses during its rainy season.
Issue
Intervention
To address water scarcity, SUNASS (Superintendencia Nacional de Servicios y Saneamiento, Peru's national water regulator) incentivized and supported public water service providers to seek out nature-based solutions to complement the standard engineering solutions utilities employed to enhance water security (Forest Trends, 2020). The national government passed the Compensation Mechanisms for Ecosystem Services Law (2014) to serve as a legal framework and to define permissible nature-based interventions (Forest Trends, 2020). Furthermore, SUNASS regulated a special water tariff to fund these nature-based solutions. Lima's water utility, SEDAPAL (Servicio de Agua Potable y Alcantarillado de Lima), committed to deploying nature-based interventions to enhance its water supply (Forest Trends, 2020).
Amunas, pre-Incan water-harvesting structures typically used in the Peruvian Andes, act as a natural sponge, capturing excess stormwater in the rainy season and redirecting it into the mountain where water is stored, thereby making it readily available during the dry season (Forest Trends, 2020; Mark, 2020; Ochoa-Tocachi et al., 2019). Amunas are stone canals that siphon water from high altitude streams during periods of heavy rainfall (i.e., during the rainy season) and funnel it into the mountain where it filters down through the rocks over the course of months, ultimately emerging from springs during the dry season (Zwick, 2015). SEDAPAL is restoring these canals (and constructing new ones) throughout the Andes to increase the volume of water made available to Lima during the dry season. Presently, one of the last, intact amunas remains in the Huamantanga community (Province of Canta), at an elevation of 3,300 m in the center of the Peruvian Andes (Ochoa-Tocachi et al., 2019). The Huamantanga amuna was used as a model to study the potential effects the amuna system could have on Lima's water security (Forest Trends, 2020).
Along with defining permissible nature-based interventions and serving as the legal basis for nature-based interventions (2), the 2014 Compensation Mechanisms for Ecosystem Services law placed special emphasis on the integration of scientific and indigenous knowledge. As a result, many of SEDAPAL's nature-based interventions, including the amunas , stem from indigenous practices that have been used throughout the Andes for centuries (Forest Trends, 2020).
In 2015, SEDAPAL approved the largest financial commitment for green infrastructure investment of any country in Latin America, announcing a $112 million investment in green infrastructure projects in and around Lima (Kenny, 2015). The $112 million investment is to be secured from municipal water services revenue and amounts to 5% of the total monthly water fees that SEDAPAL regularly collects from water users in the megacity (Kenny, 2015). The investment is intended to go towards programs designed to help the Andes adapt to climate change and improve water quality (Kenny, 2015). Of this, $26 million has been committed to "green infrastructure" programs specifically, including the restoration and construction of amunas (Kenny, 2015). A cost-curve analysis (carried out by Forest Trends and Peruvian NGO CONDESAN) indicated that the amunas' restoration would likely provide the greatest impact in terms of water security at the lowest cost (when compared with all other nature-based solutions implemented in the program) (Gammie, de Bievre & Guevara, 2015).
Challenges
The amunas project in Lima may face challenges related to the scale and complexity of restoring ancient infrastructure in remote, high-altitude areas. The physical condition of the existing amunas may require significant repairs, and constructing new ones could be costly and time-consuming. Additionally, the success of the project depends on maintaining consistent rainfall patterns and ensuring that the system is integrated effectively into Lima's modern water management infrastructure. Climate change and increasing urbanization could further strain the availability of water resources, complicating the project's long-term sustainability.
Outcomes
Modeling (based on the Huamantanga amunas) indicates that the amuna infiltration system can increase the volume of water available to Lima during the dry season by an average of 7.5% per year and up to 33% during the first dry months (Forest Trends, 2020). Ultimately, the restoration of pre-Incan amunas is a cost-effective nature-based solution that could significantly increase Lima's water supply.
Issues |
|---|
Water Scarcity and Access |
Solutions |
|---|
Alternative Water Sources & Resource Diversification |
References
Forest Trends. (2020, February 06). Connecting Indigenous Knowledge and Scientific Research for Improved Water Security. Retrieved July 28, 2020, from https://www.forest-trends.org/blog/how-to-connect-indigenous-knowledge-and-scientific-research-for-greater-water-security/
Gammie, G., De Bievre, B., & Guevara, O. (2015). Assessing green interventions for the water supply of Lima, Peru. Forest Trends.
Hommes, L., & Boelens, R. (2017). Urbanizing rural waters: Rural-urban water transfers and the reconfiguration of hydrosocial territories in Lima. Political Geography, 57, 71–80.
Kenny, A. (2015, November 17). Inside Peru's Coming Green Water Revolution. Retrieved July 28, 2020, from https://www.ecosystemmarketplace.com/articles/inside-perus-coming-green-water-revolution-2/
Lerner, D. N., Mansell-Moullin, M., Dellow, D. J., Lloyd, J. W. (1982). Groundwater studies for Lima, Peru.
Mark, A. (2015, April 16). Lima to restore pre-Incan aqueducts to alleviate its water crisis. Retrieved July 28, 2020, from https://news.mongabay.com/2015/04/lima-to-restore-pre-incan-aqueducts-to-alleviate-its-water-crisis/
Ochoa-Tocachi, B. F., Bardales, J. D., Antiporta, J., Pérez, K., Acosta, L., Mao, F., ... & Gammie, G. (2019). Potential contributions of pre-Inca infiltration infrastructure to Andean water security. Nature Sustainability, 2(7), 584–593.
Ritter, K. (2018, June 28). Water Access In Lima Complicated by Inequality and Climate Uncertainty. Retrieved July 28, 2020, from https://www.circleofblue.org/2018/south-america/water-access-in-lima-complicated-by-inequality-and-climate-uncertainty/
Zwick, S. (2015, April 30). Lima To Invest $110 Million in Green Infrastructure And Climate Adaptation. Retrieved July 28, 2020, from https://www.ecosystemmarketplace.com/articles/lima-to-invest-110-million-in-green-infrastructure-and-climate-adaptation/