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Partnerships for enhanced engagement in research (PEER) SCIENCE
Cycle 2 (2012 Deadline)

Strengthening resilience of Andean river basin headwaters facing global change

PI: Bram Willems (Universidad Nacional Mayor de San Marcos)
U.S. Partner: Christopher Scott (University of Arizona)
Project Dates: August 2013 to July 2016

Project Website:
Project Overview

Decreasing water availability in Andean river basins, rising temperatures, increased probabilities of drought occurrence, and expanding water demand all indicate that Peru will experience a severe future water crisis. This PEER project considered Andean headwaters, particularly páramos and puna wetlands, as social-ecological systems (SESs) in which coupled natural and human processes like drought, flooding, water use and impoundment in reservoirs for irrigation, and mining act together to destabilize and threaten water availability and quality for human and ecosystem purposes. Dr. Willems and his colleagues and students sought to produce better methodologies for Andean headwaters characterization by combining use of satellite imagery, products derived from their analysis (e.g., land use and land cover change), and field data (e.g., precipitation, runoff, and water use, including socioeconomic characteristics). These methodologies allowed the researchers on the project to identify headwaters, quantify their extent, and define indicators for assessing their dynamics. In turn, cross-correlation analysis between these indicators and external drivers, such as El Niño Southern Oscillation events and mining operations in headwaters, helped establish the characteristics that make Andean river basin headwaters vulnerable to global change. A second contribution of the project was the integrated assessment of Andean páramos and puna wetlands, which are far less studied than glaciers but play an even more crucial role in the hydrology of the majority of Peru’s Andean basins and the provision of water to coastal regions. In addition to the research aspects, the project also involved the goal of expanding capacity-building activities as part of the Geophysics Masters's Program at the Universidad Nacional Mayor de San Marcos.

2-359 Ayacucho Fieldwork
Fieldwork in Apacheta - Ayacucho (above 4400 m.a.s.l.).

2-359 Project team at La Montanas Lake
The project team and guides pose near La Montaña’s lake.

Final Summary of Project Activities

In the course of the project, the PEER team undertook several fieldwork trips, including to the headwaters of the Cachi basin in Ayacucho. Together with students and researchers from the University of Ayacucho (UNSCH) and  from the French Research Institute for Development (IRD), they collected soil and vegetation samples, as well as data regarding water quantity and quality in two case-study wetlands. Among their findings was that 1 meter of sediment sample included more than 2,000 years of paleoclimatic information. Such information allowed the researchers to establish possible effects of historical El Niño events through carbon storage assessments and determine whether long drought periods and climate change processes occurred in the past. Throughout the project, the researchers assessed and improved several methodologies for identifying headwater wetlands, and indicators for studying the dynamics and evolution have been validated. The team produced maps of wetland distribution for several regions in Peru. This kind of information was previously scarce, and it contributes to the efforts of the National Water Authority (ANA) in implementing the wetland inventory of Peru.

The PI and research team widely disseminated their findings, including organizing a seminar on methodologies and research experiences in geosciences at UNSCH. They also gave technical presentations at a variety of seminars and scientific events, including the AQUAFUTURA seminar of the National Meteorological Office (SENAMHI) and the National Congress of Environmental Engineering Students.

The research supported by this PEER project helped seven undergraduate and graduate students defend theses, and research team students participated in a training event organized by the National Drought Observatory. They also took part in training sessions in Colombia and Brazil.

Dr. Willems worked closely on the project to share his findings and recommendations with relevant Peruvian government agencies and align his team’s efforts with their needs and interests. The project team members actively participated in and provided support to several governmental-led initiatives. One key activity involved implementation of the National Drought Observatory (ONS), an initiative led by ANA and including the participation of the Peruvian Meteorological Service (SENAMHI), the Ministry of Agriculture, Ministry of Economy, Ministry of Environment, the Peruvian Institute of Geophysics, and UNESCO’s International Hydrological Program (UNESCO-IHP). The satellite-based monitoring system for assessing the evolution of Andean headwaters (one of the milestone deliverables of this PEER project) and the drought indicators will feed the ONS. In collaboration with their colleagues at UNPRG, the PEER team also developed the land degradation map of Piura at a scale of 1:25000 for the Ministry of Environment. This map constitutes the country's effort in combatting desertification by providing more detailed information about the state of the agricultural soils of Piura. The researchers have begun collaborating with the technical committee for the national wetland inventory, which is formed by representatives from the Ministry of Environment, the ANA and the National Wildlife and Forest Service (SERFOR). Through this collaboration, Dr. Willems and his group will share their results and methodologies for characterizing Andean wetlands and help the government agencies complete the inventory of the country. Meanwhile, the team’s hydrological models of the Apacheta basin and the wetland distribution maps have also been used for providing information requested by the Regional Government of Ayacucho.

As part of the PEER project, the PI led the design process of a new Regional Research Institute for Water - Food - Energy Security (ir-NEXUS), holding meetings with governmental entities, private companies, NGOs, USAID and the U.S. State Department. A workshop with government stakeholders was organized to identify strategic research areas for this group. Dr. Willems and his colleagues continued their efforts under a PEER Cycle 5 project entitled AGUA-ANDES: Ecological Infrastructure Strategies for Enhancing Water Sustainability in the Semi-Arid Andes, which ran from January 2017 through January 2020.


Wilmer Moncada, Bram Willems, Alex Pereda, Cristhian Aldana, and Jhony Gonzales 2022. Tendencia anual, anomalías y predicción del comportamiento de cobertura de vegetación con imágenes Landsat y MOD13Q1, microcuenca Apacheta, Región Ayacucho. Revista de Teledetección 59: 73-86.

Raul Espinoza-Villar, Jean-Michel Martinez, Elisa Armijos, Jhan-Carlo Espinoza, Naziano Filizola, Andre Dos Santos, Bram Willems, Pascal Fraizy, William Santini, and Philippe Vauchel. 2018. Spatio-temporal monitoring of suspended sediments in the Solimões River (2000–2014). Comptes Rendus Geoscience 350: 4-12.

Bastian Manz, Sebastián Páez-Bimos and Natalia Horna, Wouter Buytaert and Boris Ochoa-Tocachi, Waldo Lavado-Casimiro, and Bram Willems. 2017. Comparative Ground Validation of IMERG and TMPA at Variable Spatiotemporal Scales in the Tropical Andes. Journal of Hydrometeorology 18: 2469-2489.

Rafael de Grenade, Joshua Rudow, Rossi Taboada Hermoza, Maria Elena Adauto Aguirre, Christopher A. Scott, Bram Willems, Jennifer L. Schultz, and Robert G. Varady. 2017. Anticipatory capacity in response to global change across an extreme elevation gradient in the Ica Basin, Peru. Regional Environmental Change 17: 789-802.

Maria Carmen Lemos, David Manuel-Navarrete, Bram Leo Willems, Rolando Diaz Caravantes, and Robert G Varady. 2016. Advancing metrics: models for understanding adaptive capacity and water security. Current Opinion in Environmental Sustainability 21: 52-57.


2-359 Le Leche Fieldwork
Fieldworks in the La Leche basin, Lambayeque (Photo courtesy Dr. Willems).

Peru Partnership 6
A group photo of participants in the Cajamarca field trip surrounding Dr. Willems, center (Photo courtesy Dr. Willems).