The impact of amunas on Lima’s water security

THIS IS A TRANSLATION - THE STORY WAS SUBMITTED IN SPANISH 

Please briefly describe your Water ChangeMaker journey

Water security in large cities such as Lima is a growing concern. Peru’s capital city is home to 70 percent of the country’s population and is the source of most of its economic activity. There is growing awareness that water is not an infinite resource and that water quality is highly vulnerable. Lima’s water comes from mountains, travelling as far as 160 km from source to city. Ecosystems such as snow-capped mountains, lagoons, wetlands, grasslands and scrubland feed into it along the way, and a series of dams, canals and tunnels then direct it to the treatment plant located inside the city. These ecosystems are being devastated by human activities and climate change. In addition, the water loses a lot of its natural value on its way to the plant due to the large amount of pollutants, which are mostly found in the Rímac and Chillón river basins. In the Rímac River alone, the National Water Authority (ANA) and Lima’s water utility, Servicio de Agua Potable y Alcantarillado de Lima [Lima Drinking Water and Sewerage Authority – SEDAPAL], found over 900 pollution point sources caused by garbage dumping, wastewater discharge and mine tailings. How can water security be provided to an ever-growing city that faces such big challenges? There are several investment projects in the pipeline that aim to bring in water from further afield, such as the construction of more dams and tunnels, but Lima’s slow investment system means that these projects may take over 20 years to come to fruition. These works may be necessary, but it is essential for this type of infrastructure to be accompanied by investments in natural infrastructure.

Please describe the change that your initiative created and how was it achieved

Since 2015, The Nature Conservancy (TNC) has been running projects on climate change adaptation, via the Lima water fund, Aquafondo, in the upper Rímac River basin. The project that appealed to the communities most was undoubtedly the restoration of ancestral infiltration channels, called ‘amunas’. These channels refill the aquifers and increase base flow, making communities more resilient to drought. To do this, we mapped out the amunas, enabling us to identify 69.5 km of channels in 25 amunas distributed in the upper Santa Eulalia sub-basin, which are in varied states of preservation. Around 10.5 km of these channels have already been restored in six amunas. TNC began by restoring the Saywapata amuna in San Pedro de Casta in 2016, and the Huaycananpo amuna in San Juan de Iris in 2017. Aquafondo then restored the Huytama amuna in 2017 and the Shucuni-Laguna Cercano amuna in 2018. The Pontifical Catholic University of Peru also restored the Laguna Prestancia amuna in 2018, and most recently, TNC restored the Shucuni-Chinchaycocha amuna in 2019. TNC and Aquafondo plan to restore a further 4 km of amunas in San Pedro and 2 km in San Juan de Iris. We are coordinating with SEDAPAL, who will be responsible for maintaining these amunas, ensuring their sustainability. Interestingly, within just two years of the amunas being in operation, the local population has seen improvements in the water supply, which has provided them with more water in the low-water season.

How did your initiative help build resilience to climate change?

Hydrological monitoring of the Saywapata amuna allowed us to determine its efficiency in refilling the aquifer. It revealed an infiltration rate of 88.7 litres per second per kilometre, which is equivalent to 225,800 m3 going into the soil. Similarly, the delay between the amuna and the springs downstream showed that concentration was higher between 3 and 38 days after the tracer was thrown in. As such, it is recommended that monitoring be continued to determine whether the same occurs during the low-water months (July and August). Based on this observation, it has been estimated that restoring the 25 amunas will enable 3 million m3 to be stored in the basin, which is equivalent to 1,200 Olympic swimming pools. Furthermore, its low cost means that this type of semi-natural infrastructure perfectly complements grey infrastructure, such as the future Autisha dam on the Santa Eulalia river.

What water-related decisions did your initiative influence or improve?

The amunas have received a lot of interest from Aquafondo’s partners, including multinational companies such as Backus, Nestle and Orbia, due to their efficiency in regulating water and because they value ancestral practices. This is in addition to SEDAPAL, which has a compensation fund for ecosystem services on account of the water tariff. It is interested in maintaining these amunas which would not only help to retain more water in the basin, benefiting the future Autisha dam, but also help prevent alluvium, which makes drinking water treatment impossible for the city. Similarly, the Ministry of Environment and the National Superintendence of Sanitation Services are very interested in protecting high Andean ecosystems and in achieving the Sustainable Development Goals (SDGs) and Nationally Determined Contributions (NDCs), both of which value ancestral knowledge. Finally, restoring the amunas generates economic income for the surrounding communities. Seventy percent of each amuna’s restoration costs are spent on local labour, providing significant economic support to the area’s inhabitants. This contrasts with grey infrastructure labour costs, which comprise no more than 25 percent of the budget.

What were some of the challenges faced and how were they overcome?

The amunas have received a lot of interest from Aquafondo’s partners, including multinational companies such as Backus, Nestle and Orbia, due to their efficiency in regulating water and because they value ancestral practices. This is in addition to SEDAPAL, which has a compensation fund for ecosystem services on account of the water tariff. It is interested in maintaining these amunas which would not only help to retain more water in the basin, benefiting the future Autisha dam, but also help prevent alluvium, which makes drinking water treatment impossible for the city. Similarly, the Ministry of Environment and the National Superintendence of Sanitation Services are very interested in protecting high Andean ecosystems and in achieving the Sustainable Development Goals (SDGs) and Nationally Determined Contributions (NDCs), both of which value ancestral knowledge. Finally, restoring the amunas generates economic income for the surrounding communities. Seventy percent of each amuna’s restoration costs are spent on local labour, providing significant economic support to the area’s inhabitants. This contrasts with grey infrastructure labour costs, which comprise no more than 25 percent of the budget.

In your view: Will the change that was created by your initiative continue?

We are in talks with SEDAPAL to maintain the restored amunas, and those to be restored, through the Mecanismo de Retribución por Servicios Ecosistémicos [Compensation Mechanisms for Ecosystem Services – MERESE] fund. SEDAPAL would oversee the operation and maintenance of all amuna channels as part of the water tariff. An estimated PEN 10,000 per kilometre will be invested in maintaining the amuna channels.

What did you learn during the initiative or after? And is it possible that others could learn from you?

The key lessons learned are as follows: There are 60 km of amunas to restore, which, if completed, could increase the volume of groundwater by 3 million m3. This would help improve water distribution in the low-water season, reduce the likelihood of landslides in the upper basin and increase resilience to climate change. Given the complex economic situation that COVID-19 has placed us in, implementing this type of solution not only helps improve water security, but also helps increase communities’ economic income: around 70 percent of each amuna’s restoration costs are spent on local labour. There has been a high level of participation from women in the restoration of the amunas. Combining amuna restoration with grey infrastructure works is key to increasing SEDAPAL’s planned dam storage in the basin. Amunas contribute to the achievement of SDG 6, NDCs and other climate-related goals. Following my experience of the restoration of the six amuna channels, and hydrological monitoring of one of the amunas, I have published a book on the Impacto de las amunas en la seguridad hídrica de Lima [Impact of amunas on Lima’s water security], which can be downloaded for free, and also a summary of the most important points at the following page: https://www.fondosdeagua.org/es/blog-y-noticias/blog/solucion-agua/