A project at the San Juan Apóstol school will reuse up to 70% of the water consumed, while the Water Alliance Fund is preparing rain gardens and studies in the Quilca-Chili basin to address the growing water demand in Arequipa.
While progress is being made in the upper reaches of the Quilca-Chili basin with water harvesting and storage projects to address climate change and the growing demand for this resource, initiatives are underway in the middle zone—where Arequipa is located—focused on making better use of the water that already reaches the city. One of these projects will begin operating in February 2026 at the San Juan Apóstol school, located in the arid Villa Cerrillos area of Cerro Colorado.
Greywater treatment technology will be installed to treat water from handwashing and showers. The project is supported by the Water Alliance Fund, an initiative of the Catholic University of São Paulo that creates a collaborative space to promote water sustainability.
Executive coordinator Luis Gutiérrez explains that this reuse will allow them to utilize between 60 and 70% of the potable water consumed on campus to irrigate green areas and supply the restrooms. The reduction in monthly consumption could reach 30%, which will be reflected in a lower water bill, currently around S/ 1700 per month.
The project, implemented in partnership with Remote Waters and with an investment of $4,500, will not only generate an economic and environmental impact, but will also foster a culture of responsible water use among students. These initiatives are especially important when schools are struggling with water debt.
RAIN GARDENS. The fund is also promoting the implementation of the "rain gardens" project to take advantage of rainfall that usually causes damage in the city due to flash floods. The idea is planned for the Enace ravine in the Cayma district, which has already undergone a tree-planting project along its banks.
Gutiérrez explains that the proposal involves burying cells to store runoff water and then using it to create green spaces along the riverbanks, promote more vegetation, and recharge underground aquifers. Furthermore, the presence of vegetation would help prevent flooding and illegal settlements near the ravines. If successful, this intervention could be replicated in other vulnerable areas of the city.
CHALLENGES IN THE LOWER BASIN. A characterization study will be conducted in the lower part of the basin, specifically in the district of Quilca, which receives runoff contaminated with salt due to agrochemicals. This study aims to identify the projects needed to reverse this situation. According to the specialist, the district has stopped cultivating crops such as tomatoes, rice, and wheat, opting instead for bean production to reduce the risk of contamination.
Gutiérrez warns that numerous beach house real estate projects are also being developed in this area, without considering the limited availability of drinking water. The local population already faces restrictions, so the authorities must anticipate future pressure on the water system.
DEMAND AND INVESTMENTS. Last November, the Catholic University of San Pablo presented a diagnostic study of the Quilca-Chili basin. The study projects that by 2030, water demand in Arequipa will increase by 34.2% due to population growth. To address this scenario, projects are needed to ensure the conservation of ecosystems in the headwaters of the basin, the region's main water source.
Along these lines, the Water Alliance Fund is also financing the revegetation of grasslands on two hectares of the Salinas y Aguada Blanca National Reserve, with an investment of S/ 20,000. At the same time, the updated 2023 Water Resources Management Plan for the basin identifies projects worth more than S/ 4.5 billion, necessary to strengthen regional water security.