Proyecto PEER: "AGUA-ANDES: Ecological Infrastructure Strategies for Enhancing Water Sustainability in the Semi-Arid Andes"

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Director: Dr. Bram Willems, PI (

Funded by the PEER Program of USAID

Participating Institutions

  • Centro de Competencias del Agua (Perú)
  • University of Arizona (USA)
  • Universidad Nacional San Cristóbal de Huamanga (Perú)
  • Universidad Nacional Agraria La Molina (Perú)
  • Universidad Peruana Cayetano Heredia (Perú)
  • Research Institute for Development - IRD (France)
  • Imperial College London (UK)
  • University of the West of England (UK)
  • Regional Government of Ayacucho (Perú)
  • Asociación Bartolome Aripaylla (Perú)

Project Summary

project sits in “Pasteur’s Quadrant” of
research that advances basic science about coupled natural and human systems, with the goal of informing practical solutions to water sustainability (Clark & Dickson 2003). The project focuses on Ecological Infrastructure (EI) as an adaptation strategy for ensuring water sustainability in South America’s Semi-Andes region.

Within the natural sciences, we seek to advance our understanding of ecohydrologic processes that take place in headwaters ecosystems, effects of changes in climate and anthropogenic drivers, and how these are reflected in the water supply along the basin. Andean puna wetlands are far less studied than tropical glaciers, but play an even more crucial role in the hydrology of the majority of Peru’s Andean basins and hence in the provision of water to urban and productive centers of the country. As glaciers have almost disappeared in our study-site, this project will produce relevant information for climate change adaptation plans by generating new knowledge about post-glacier hydrological processes in the Andes. In addition, we will study the eco-hydrological properties of human-made water-regulating ecosystems and their scalability for ecological interventions in urban and rural areas. The integrated research of linkages between natural and human-made water cycle is an upcoming scientific topic worldwide, which responses to the demand for innovative solutions to address challenges imposed by global change processes on water sustainability (EC 2012).

Within the social sciences, we seek to better understand how actors make decisions around EI. Specifically, we want to know how decision-makers receive information and learn about ecological infrastructure design and implementation, and what obstacles are faced in understanding and advancing ecological infrastructure. This entails understanding trade—offs decision-makers face with regard to strategic planning, public investments and institutional capability. Our objective then is to establish an integrated, participatory approach to the design and implementation of Ecological Infrastructure Strategies (EIS) that can be utilized in Peru’s Andean urban centers and communities.  This research will address a key challenge in understanding how society undergoes changes in the use and distribution of environmental resources, and contribute to our understanding of decision-making around water sustainability more broadly.

Project Description


In the face of demographic and global change, sustainability, particularly of water resources in arid and semiarid regions, has become a key challenge. Water is the main limiting resource and is a coupling agent linking natural systems and human systems to each other. Nearly 40% of the Peru’s extension is drylands, with only 2% of the water resources draining to the arid coast, region that hosts about 60% of the population and whose contribution to the GDP is around 80% (MINAM 2011). The water supply of the Pacific coast depends critically on the Andean headwaters ecosystems: precipitation generated by the tropical forest in the Amazon is stored during the rain season and steadily released during the dry season to both slopes of the Andes. Climate change has altered precipitation patterns and shifted temperatures in the high Andes and, as a consequence, tropical glaciers have dramatically withdrawn over the past decades – almost disappeared in many areas – reducing substantially their contribution to headwater wetlands and water bodies during the dry season (Vuille et al. 2008; Buytaert et al. 2009 and 2011). The dependence on the headwaters is no longer exclusive for the big urban centers along the coast, but has also become a main issue for growing cities in the semi-arid eastern slope of the Andes, such as the capital of Ayacucho, Huamanga.

Ayacucho forms part of Peru’s “poverty triangle” and faces a constant water-scarcity situation. Triggered by the internal conflict during the decades of the 1980s and 1990s, and further driven by the persistence of low well-being conditions and lack of opportunities in the rural areas, the region main population centers have experienced a rapidly and non-planned expansion, growing at a faster pace than the government’s capacity to cope with the demand for basic services, such as water and sanitation (MVCS 2014). Coupled to demographic growth, new market opportunities have fueled the expansion of high water demanding productive activities, such as agriculture (with a shifting to higher altitudes), cattle raising (with subsequent overgrazing), mining and hydropower production, further increasing pressure on water resources and ecosystems, and exacerbating competition between the different users, which frequently unchain social conflicts (Viviroli et al. 2011; Bebbington & Bury 2009; Vergara et al. 2007). To complete the “vicious cycle”, a systematic contamination of the basins has been caused by the release of wastewater (household, industry) without treatment and dumping of solid waste (MVCS 2014). 


Disproportionate increases in population and land transformations are characteristics of water-limited arid and semiarid cities worldwide, resulting in altered hydrosystems and biogeochemical cycles (Ezcurra 2006; Kaye et al. 2006; Grimm et al. 2008). Cities have always faced challenges in providing clean water for municipal and industrial uses, and in dealing with the environmental water quality and flooding risks that accompany urbanization (Sachs 2006). Water sustainability will require a continuing investment in infrastructure and will require new strategies - technological, social, and political - to adapt growing demand and cities to resource limitations (UN 2013). Ecological infrastructure are multifunctional system of open spaces that integrates ecological processes with the water cycle, and offers cost-effective, efficient and timely solutions for water storage, water-treatment, recharge of aquifers, and buffering of flooding, among others; constituting an adaptation strategy for the safeguarding of water supply (Eisenberg et al. 2014).

There is evidence of EI adoption and development that impacts our study region. The Government of Peru (GOP) has taken the first steps to complement the traditional gray infrastructure for water supply and regulation with investments in EI. The Payment for Ecosystem Services Law of 2014 allows water utilities to destine a percentage of the water tariff for investing in EI solutions. In addition, the GOP has published guidelines for restoration of ecosystems and ecosystem services, prioritizing hydrological regulation and control of soil erosion. Despite these recent adoptions and new priorities, Ayacucho still lacks of an EI strategy. From our vast work experience in Peru, we have identified four key development challenges that are illustrative of larger national challenges:

  1. There is low scientific evidence regarding the value of EI for water resources management,
  2. Politicians and decision makers have little understanding about the importance of EI for water resources management,
  3. There is an absence of a critical mass of professionals working at the local governmental entities that can put forward EI interventions, and
  4. Institutions tend to work separately and there is no alignment between sectorial planning.

The first two challenges will be addressed in the research plan, while the remaining two in the development strategy.

Project Objectives

The goal of our project is to develop the regional science necessary to understand and improve linkages between ecosystem services in the semi-arid Andes and governance for water sustainability. To achieve this goal, four primary objectives have been developed:

(PO1) Identify and understand the properties and dynamics of water-regulating Andean ecosystems. Knowledge about the eco-hydrological properties of ecosystems for water-storage and water-treatment is key for incorporating EI into water resource planning. Decision makers need concrete information about the economical value of such ecosystems and in how far these could replace/complement conventional grey infrastructures, among others.

(PO2) Generate robust scenarios of ecosystem management at the local scale for medium and long future time horizons. From our experience of working with stakeholders, planning is usually based on qualitative perceptions and simplified assessments of trends of parameters, such as demographic growth, temperature and precipitation. GCM and RCM models still provide too coarse information for water resource planning, with timeframes beyond to what is needed, so decision-making is subjected to several sources of uncertainty. Scenarios will be crafted and shared through a participatory process with stakeholders. 

(PO3) Establish ecological infrastructure strategies for increasing water availability and quality in urban and rural areas of the semi-arid Andes. These EI strategies will be developed in participation with decision-makers and stakeholders. We will utilize interviews and surveys to better understand how actors learn about and share information related to EI and the obstacles faced in EIS design and implementation.

(PO4) Engage in capacity building the local university, government, communities and the productive sector by educating a new generation of professionals with sound scientific knowledge and management capacities, which we claim is critical for an optimal governance of water and natural resources in general. Local universities are suitable platforms for accelerating learning processes by articulating key actors surrounding the joint development of demands-driven research projects and capacity building processes.

PO 1 to 3 will be addressed through the research activities described in the research plan, while the capacity building component (PO4) is transversal to the whole process and is explained in Section 5.

Research Plan

The research plan design is schematized in Figure 2. The activities are grouped within interrelated working-packages (WP), each addressing one of the POs (1 to 3), which altogether allow for the establishment of an effective science-policy dialogue. The research design also takes into account the interdisciplinary character of the research team, which includes researchers, water managers and NGO workers with experience in EI projects in the Andes. By adopting a demands-driven focus, each WP will deliver concrete scientific products (knowledge, models, EI experimental facilities) and support tools for decision-making processes (e.g., scenarios and EI strategies).

-----Figure 2-----

WP1. Assessment of the eco-hydrological functioning of headwaters wetlands: Two pilot wetlands in the headwaters of the Cachi basin will serve as field laboratories. To quantify the volume of water released by the wetlands into the rivers, we will perform hydraulic conductivity measurements, hydrological gauging (surface water and water-table level, discharge) and isotopic tracer analyzes (to differentiate the residence times of different processes such as glaciers, wetlands and subsurface flows) at different spots to ensure statistical representativeness.

We will study the potential effects of climate change on the water-regulating properties of the case-study wetlands (Buytaert et al. 2011). For instance, preliminary results reveal a shifting of the vegetation regime to changes in water-table: Disticha Muscoides species are replaced by the more water-stress-resistant and lower quality Aciachne Pulvinata (Portal et al., in preparation). Here, we’ll expand the research to linkages with the accelerated withdraw of the main glaciers in the headwater region and in how far this vegetation shifting affects water quality and water-storage capacity of soils, and alters evapotranspiration spatial patterns and whether this disturbs the local climate (e.g. precipitation patters). Complementary, sediment analysis will be performed in order to estimate the carbon storage capacity of these wetlands and identify possible patterns that could be related to paleoclimate studies reported for the Andes (e.g. occurrence of strong and long-standing El Niño events).

Ecosystem quality will be assessed along transects by studying distributions of macro-invertebrate families in streams, soils and vegetation. Macro-invertebrates will be sampled and separated through a set of sieves and preserved. Insects will be sorted and identified to family level and non-insects to higher taxonomic levels using a digital camera, stereomicroscope, and taxonomic guides. Annual family richness and abundance averages will be determined for each site. Taxonomic identification reflects the biodiversity and can be converted to a value using an internationally accepted index that can then be used to describe water quality.

WP2. Assessment of the water-treatment capacity of ecosystem-based designs: We will support UNSCH initiative to construct an experimental facility for assessing cost/benefits and scalability of EI interventions in urban areas. Starting from previous experiences in Peru and the US, we’ll work on the design of a multipurpose research facility consisting of experimental plots for assessing combinations of systems with open water surface flow, subsurface flow through a gravel or soil media, or aquatic systems with deeper water and floating aquatic plants. Flow regimes will be regulated with inlet/outlet valves.

At the plot scale, plant-matrix combinations will be studied for evaluating water treatment and precipitation storage properties of native and non-native species. Water quality analysis will be performed periodically by measuring physiochemical (pH, temperature, conductivity, turbidity and dissolved oxygen) and biological properties (e.g., population of macro-invertebrates and insects). The results will be compared with the quality standards for water reuse approved by the GOP in order to identify potential uses of the reclaimed waters (irrigation for parks, agriculture and ecosystems). The research will also address potential negative effects that could be caused by changing climatic and/or hydrological conditions, such as appearance of invasive species or odor problems, and evaluate social acceptance, among others.

WP3. Water budget analysis: Water budget analysis and the assessment of effects of introducing water-regulating ecosystems (e.g., wetlands, forest and grasslands) will be done by building an (eco-) hydrological model for the studied catchment. For this, we will extend a tailored model for tropical alpine ecosystems and wetlands developed by Buytaert and Beven (2011), which is based on the widely used TOPMODEL.

First, input parameters that are representative for the local and basin-scale will be prepared:

  • Meteorological inputs for the model will be generated by processing time series of temperature, evapotranspiration and precipitation data recorded in 15 meteorological stations distributed along the Cachi basin.
  • The gauging network data will be complemented with satellite products (e.g., TRMM and MODIS) to fill spatial and temporal gaps by means of statistical merging techniques (Manz et al. 2016). As a result, precipitation, evapotranspiration and temperature maps will be produced for the study area.
  • Land-use, hydro-unit and connectivity maps will be developed using pattern recognition techniques on LANDSAT and MODIS images, which validated by ground truthing, will provide us with an integrated basin-scale view of the land-uses (e.g., urban areas, ecosystems, agriculture) and waterways (Garcia et al. 2015).

Models will be then validated against runoff data collected in gauging stations at the study-case wetlands and distributed along the Cachi basin.

WP4: Scenario building: In simple terms, scenario building is about inferring drivers that could alter the natural and man-made water cycle, and its impacts on the availability and quality of water by introducing changes in climate, land-use systems and waterways. In order to integrate different points of view, stimulate the discussion and exchange of perspective and experiences between stakeholders of the basin, the scenario building will be done through a participatory process. On a periodical base, we plan to organize sequential workshops to which policy makers, representatives from the local governments, water utilities, local water authority, community leaders, NGO’s and scientists will be invited, for discussing (Schütze 2015):

  1. Problem framing and definition of boundary conditions
  2. Identification of driving forces (descriptors)
  3. Formulation of possible developments of descriptors (sub-scenarios)
  4. Evaluation of descriptor dependencies
  5. Construction of consistent scenarios
  6. Scenario transfer: analysis of consequences and development strategies

This process will be complemented with quantitative projections using the validated hydrological models, which will be run for several climatic and socio-economic scenarios. For the climate scenarios, a bottom-up approach will be used, i.e., first we’ll determine the vulnerability domain of the study region, link this to climate conditions and determine plausibility of climate conditions vulnerability.

WP5: Ecological Infrastructure Strategies (EIS) design: The scenario building process (WP4) will result in a set of possible future development pathways for the Cachi basin, upon which strategies must be designed in order to ensure water sustainability, the main limiting resource in the semi-arid Andes. A primary question to address is which EI interventions should be prioritized, where and at what scale. EIS integrates natural and man-made water-regulating ecosystems with landscape planning, urban planning, and water and wastewater management, giving due and balanced consideration to social, economic and environmental factors, and involving local authorities and community organizations (Eisenberg et al. 2014).

Through a participatory process similar as the one adopted in WP4, the EIS will be constructed by integrating multiple-scales (basin, sub-basin, cities and population centers and pilot-areas) and multiple-functions of EI (e.g., water harvesting, flooding buffering in vulnerable sites, infiltration, water-treatment, precipitation storage, improve socio-economic conditions adding economic value, promote of re-use of urban waters) (EC 2012). The research team will document the information and lessons learnt, and systematize the activities to ensure a constructive process.

First, potential services that could be provided by EI at different areas of interest will be identified. By dividing the basin into geomorphological units (e.g. headwaters, valleys, ravines, low-slope extensions, etc.), charts will be developed summarizing the problems, potentials and future possibilities. This contextualization assessment will result in a group of objectives for water planning including EI.

The second step consists in harmonizing EI interventions with broader policies on water management, solid waste management, territorial planning, agriculture, forestry, health, economic development and climate change, among others. One key aspect will be the identification of spatial processes within these policies that could be improved and/or have more impact by introducing EI. As a result, a set of core principles will be established for the EIS.

Finally, we will assess the application of the EIS principles to water management. For this, governance issues, such as strategic planning, public investments and institutional capability, among others, will be discussed and analyzed in order to identify bottlenecks and potential hidden trade-offs (e.g., reducing surface flow, invasive species) that could challenge EI interventions.

The experience will be systematized into a set of best practices to guide EI investment processes and program design and adoption by the government.  


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