Civil and Structural Engineering, Earth-Surface Processes, Aquatic Science
38
Scopus Publications
Scopus Publications
Assessing hydrological responses to large-scale native forest restoration as a nature-based solution in South-Central Chile under climate change Marieta Hernández-Sosa, Mauricio Aguayo, Nicolás Cortés-Torres, Alejandra Stehr, Félix Frances, Ovidio Llompart Nature Based Solutions, 2026 Forests play a fundamental role in regulating the hydrological cycle and providing essential ecosystem services, functions that are increasingly threatened by climate change and human activities. Chile offers a relevant context for examining the relationship between land use change and hydrological processes, given its history of landscape transformations and growing water stress in the south-central region. Under the RCP8.5 climate scenario, four forest restoration scenarios were simulated using the TETIS hydrological model. These scenarios were designed based on national policies, Nature-Based Solutions (NbS) principles, and social criteria, and applied to two sub-basins of the Imperial River in the Araucanía Region. Our findings show that the combined effects of climate change and land use change produce the largest variations in hydrological processes. Increases in forest cover led to higher evapotranspiration, particularly under exotic plantation scenarios. Although streamflow generally declines, scenarios with native forest restoration in mid-to-upper basin areas provide a buffering effect on streamflow, especially during dry seasons. Large-scale native forest restoration enhances water retention and hydrological stability, whereas plantation-dominated reforestation results in the greatest water losses, particularly in dry years. These results highlight the effectiveness of NbS-oriented native forest restoration in maintaining water security, regulating hydrological flows, and supporting climate adaptation, providing actionable guidance for watershed management and policy development in Chile.
Estimating the Seasonal Variations of Multiple Recharge Sources’ Contribution in Mountainous Mediterranean Basins Rayen Rivera‐Vidal, José Luis Arumí, Víctor Parra, Alejandra Stehr, Verónica Oliveros, Matías Taucare, Jordi Escorcia Hydrological Processes, 2026 Groundwater in mountain–valley systems plays a crucial role in sustaining river baseflows, irrigation, and water security, yet the mechanisms and seasonal variability of aquifer recharge remain poorly quantified. This study investigates the seasonal variability of groundwater recharge sources in the Ñuble–Perquilauquén basins of Central Chile, a representative Mediterranean mountain system. A process‐based hydrological model (SWAT) was complemented with stable isotope analysis (δ 18 O, δ 2 H) and a Bayesian mixing model (MixSIAR) to quantify the relative and absolute contributions of three recharge mechanisms: diffuse, focused, and mountain‐front recharge (MFR) derived from Cordilleran precipitation, springs and snowmelt. Results indicate that total recharge to the lowland alluvial aquifer varies seasonally from ~8.5 to ~27.2 mm/month in the dry and the rainy seasons, respectively. Diffuse precipitation‐driven recharge dominates in winter (45%–61%), focused recharge prevails in summer (60%–65%), and MFR provides a stable 11%–17% contribution throughout the year. Irrigation return flows contribute approximately 8% of total diffuse recharge in the valley zone, partially sustaining aquifer replenishment during dry months. The combined SWAT–MixSIAR framework reveals that the Andes Mountains act as a perennial source of groundwater from mountain‐front and, potentially, mountain‐block processes. These findings underscore not only the role of mountainous areas as a water reservoir for lowland aquifers, but also the relevance of integrating different approaches when estimating groundwater recharge.
Managed aquifer recharge implementation challenges: Lessons from Chile's water-scarce regions Rayen Rivera-Vidal, José Luis Arumí, Ovidio Melo, Verónica Delgado, Víctor Parra, Alejandra Stehr, Linda Daniele Groundwater for Sustainable Development, 2025 As water scarcity intensifies globally due to climate change and growing demand, Managed Aquifer Recharge (MAR) is increasingly recognized as a vital nature-based strategy for sustainable groundwater management. Yet, its implementation remains insufficiently adopted in many water-stressed regions. This study addresses the critical gap in understanding the socio-technical and institutional barriers that hinder the widespread adoption of MAR, focusing on Chile—one of Latin America's most water-stressed country. A mixed-methods approach was employed, integrating qualitative policy analysis, quantitative case study evaluations, and a semi-systematic review of 70 international publications. Key findings reveal persistent challenges, including limited hydrogeological data, weak institutional coordination and lack of clear quality standards. The 15 MAR initiatives analyzed in Chile show wide variation in design, scale, and implementation context. Success often depends on local hydrogeological knowledge, active involvement from water users and sustained institutional support. International case studies illustrate that, while some challenges are highly context-specific, others—such as low public awareness, regulatory gaps regarding water reuse, and insufficient monitoring—are widespread across diverse geographic and institutional settings. This study provides a comprehensive framework for overcoming barriers to MAR implementation, highlighting the importance of adaptive legal frameworks, scientific monitoring and proactive stakeholder engagement. Based on Chilean and international experience, the study proposes a sequenced set of short-, medium-, and long-term policy recommendations to guide MAR development. The insights gained offer valuable guidance for countries worldwide seeking to enhance water security through strategic groundwater management. Future research should focus on developing adaptive governance models and mechanisms for sustained stakeholder collaboration.
Multi-temporal assessment of a wildfire chronosequence by remote sensing F. Nájera De Ferrari, E. Duarte, C. Smith-Ramírez, A. Rendon-Funes, V. Sepúlveda Gonzalez, N. Sepúlveda Gonzalez, M.F. Levio, R. Rubilar, A. Stehr, C. Merino, I. Jofré, C. Rojas, F. Aburto, Y. Kuzyakov, E. Filimonenko, J. Dörner, P. Pereira, F. Matus Methodsx, 2024 The study aimed to develop a methodological framework to identify forest ecosystems affected by wildfires and evaluate their recovery chronologically. To do this remote sensing analysis, sites with burn scars were selected based on various criteria (fire severity, affected area, vegetation and soil type, slope, aspect, and one-time occurrence of wildfire in the last 23 years). Spectral vegetation indices (VIs) from satellite imagery were used to estimate burn severity and vegetation cover changes. Images of surface reflectance were obtained from the collection of Landsat 5 ETM, Landsat 7 ETM+, and Landsat 8 OLI/TIRS, available and processed on the Google Earth Engine Platform (GEE). Indices VIs (i) the normalized difference vegetation index (NDVI), (ii) the normalized burn ratio (NBR), and (iii) the differenced normalized burn ratio (dNBR) were calculated to classify burn severity. The one-time occurrence selection was performed using the LandTrendr algorithm to monitor changes in land cover and burned areas. To validate the selection, the chosen sites within the chronosequence were clustered on 4 seasons of soil properties and litter accumulation recovery. Our result can guide methodological comparisons and forest management practices on large surfaces by comparing parches of different time-affected ecosystems. Validation sites of the cluster chronosequence shows consistent recovery of soil properties as soil carbon, bulk density and litter accumulation through the studied years •The study developed a framework to identify wildfire-affected forest ecosystems and evaluate their recovery using remote sensing and local data.•Vegetation indices (NDVI, NBR, dNBR) from Landsat satellite imagery processed on the Google Earth Engine were used to assess burn severity and vegetation changes over time.•Selected sites were validated using the LandTrendr algorithm and monitored for seasonal changes in soil properties and litter accumulation.
Assessment of water quality trends through the application of an aggregated water quality index with historical monitored data in a Mediterranean Andean basin Pablo S. González, Alejandra Stehr, Ricardo O. Barra Ecological Indicators, 2024 • Data from state agencies provide valuable information for assessing water quality. • It is possible to evaluate water quality over time with supplemented public data. • Water quality in the Mataquito River basin has declined over the last 40 years. • Highest water quality occurs at basin outlet in winter, and Andes station in spring. The Water Quality Index (WQI) is an essential tool for monitoring trends, conducting scientific research, and making informed decisions. It offers a comprehensive view of the spatiotemporal variation in water quality in a watershed. Water quality data from various environmental assessment sources are often scattered and contain valuable information that researchers do not use. This study addresses the challenge of analyzing temporally and spatially dispersed monitoring data to assess water quality in riverine ecosystems over time. Our objective was to investigate fluctuations in water quality by constructing an aggregate water quality index, combining data from multiple public monitoring initiatives over 40 years in the Mediterranean region of central Chile, specifically in the Mataquito River Basin. Hydrochemical data were obtained from the measurement records available through the National Water Quality Monitoring Network of the Dirección General de Aguas of the Ministry of Public Works, integrating additional information from the water quality output station in the basin, which included sources from the Ministry of the Environment. Outliers for each parameter were removed and a data availability criterion was defined in relation to the total number of campaigns. Missing data were imputed to complete the matrix of water quality parameters. A total of 550 sampling campaigns provided 6624 water quality data points distributed across 10 chemical parameters and two chemical indicators, which were used to calculate the water quality index. The aggregation WQI water quality function was calculated using a modified additive method. Our research revealed that supplemented data offer valuable insights into evaluating water quality in the river ecosystems of the Andean watershed. In the lower zone, the water quality was determined to be good, while in the middle of the basin near the Andean Cordillera, it was considered acceptable. The analysis of the WQI over a decade indicated changes in water quality, irrespective of the station location in the watershed and the level of human intervention. The WQI values suggest a decrease in the water quality over the past 40 years. This study demonstrates that integrating information from diverse environmental monitoring sources into a WQI can be used to assess water quality trends and patterns in the Andean watersheds of Central Chile over time and space. These findings have significant implications for water management and decision making, providing a solid foundation for implementing appropriate strategies aimed at preserving water quality and ensuring water security in central Chile.
Interdisciplinary solutions and collaborations for wildfire management Fay Johnston, Charles Jones, Fang Li, Alejandra Stehr, Miguel Ángel Torres-Vázquez, Marco Turco, Sander Veraverbeke Iscience, 2024 The Earth system has long lived with fires, 1 , 2 but the impact of climate change on fire regimes has led to extreme wildfire events with higher intensity and faster spread. 3 , 4 , 5 This has effects on ecosystems and resources, air pollution, and, ultimately, human societies. 6 Facing these compounding challenges require interdisciplinary solutions and collaborations. In this Backstory, we bring together fire researchers across fields, aiming to foster discussions and collaborations across disciplines, for us to better understand how we can learn to "live with fire".
Drought and Wildfire Trends in Native Forests of South-Central Chile in the 21st Century Efraín Duarte, Rafael Rubilar, Francisco Matus, Claudia Garrido-Ruiz, Carolina Merino, Cecilia Smith-Ramirez, Felipe Aburto, Claudia Rojas, Alejandra Stehr, José Dörner, Francisco Nájera, Guillermo Barrientos, Ignacio Jofré Fire, 2024 Over the last decades, Chile has experienced a long-term drought with significant consequences for water availability, forest productivity, and soil degradation, ultimately dramatically increasing the surface of burned area. Here, we quantify the Palmer Drought Severity Index (PDSI) to ascertain the extent of “moisture deficiency” across the central-southern region of Chile from 2000 to 2023 to assess the drought’s relationship with the frequency of wildfires focusing on the impact of native forests. Our methodology quantifies the PDSI from the burned area data using MODIS MCD64A1 satellite imagery, validated by in situ wildfire occurrence records. The findings indicate that 85.2% of fires occurred under moderate to severe drought conditions. We identified 407,561 ha showing varying degrees of degradation due to wildfires, highlighting the critical areas for targeted conservation efforts. A significant increase in both the frequency of wildfires and the extent of the affected area in native forests was observed with the intensification of drought conditions in the 21st century within mesic to humid Mediterranean climatic zones where drought explains up to 41% of the variability in the burned area (r2 = 0.41; p < 0.05). This study highlights the relationship between drought conditions and wildfire frequency, showing the paramount need to adopt comprehensive wildfire mitigation management in native forests.
Evaluation of climate-change impacts on the temporal and spatial behaviour of drought in South-Central Chile Andrea Bobadilla, Alejandra Stehr, Nicolás Toro Hydrological Sciences Journal, 2024 Chile is particularly vulnerable to climate change due to its geomorphology, ecological wealth and economic dependence on water resources, and has been facing a severe drought since 2010. The objective of this work is to propose a methodology able to project and evaluate changes in the magnitude, duration and frequency of meteorological and hydrological droughts, as a decision-making tool to support adaptation to climate change. Four basins were assessed using different downscaled General Circulation Models (GCM) and the Soil & Water Assessment Tool (SWAT) model. Results were evaluated using Standardized Precipitation Index (SPI) and Standardized Streamflow Index (SSFI) comparing drought events over two periods of time. An increase in magnitude and duration of meteorological droughts is projected, especially in the Andes Mountain range. Regarding hydrological drought, greater increases in magnitude and duration are projected for the Itata River Basin. In both types of droughts, an increase in frequency is expected.
The status quo effect in the sociohydrology of floods Catalina Mendoza Leal, Rocío Coloma, Diego Ponce, Benjamín Alarcón, Maricarmen Guerra, Alejandra Stehr, Juan Antonio Carrasco, Hernán Alcayaga, Octavio Rojas, Felipe Link, Oscar Link Hydrological Sciences Journal, 2024 Two behavioural types in sociohydrology of floods have been described in more detail than others: the levee effect and the learning effect. However, additional types of behaviour operate and need further research. Taking the case of frequent flash floods occurring in an ephemeral stream, a tributary of the Vilama River, located in San Pedro de Atacama, Chile, at the interphase between the Atacama desert and the Andean Altiplano, we explore the existence of further behavioural types in the sociohydrology of floods at four neighbourhoods along the tributary. Fieldwork to reconstruct a recent flood event, hydrological analysis and semistructured interviews with key informants to characterize people’s responses to floods were conducted. Results show evidence that the so-called status quo effect is present at the riparian community scale, i.e. when communities do not learn and adapt to prevent damage even when exposed to frequent floods. Possible causes of the status quo effect are discussed.
Forest hydrology in Chile: Past, present, and future Francisco Balocchi, Mauricio Galleguillos, Diego Rivera, Alejandra Stehr, Jose Luis Arumi, Roberto Pizarro, Pablo Garcia-Chevesich, Andrés Iroumé, Juan J. Armesto, Pedro Hervé-Fernández, Carlos Oyarzún, Pilar Barría, Christian Little, Gabriel Mancilla, Santiago Yépez, Rolando Rodriguez, Don A. White, Richard P. Silberstein, Daniel G. Neary, Pablo Ramírez de Arellano Journal of Hydrology, 2023
Modelling hydrological response to climate change: Experiences from two South - Central chilean watersheds American Society of Agricultural and Biological Engineers Conference on 21st Century Watershed Technology Improving Water Quality and Environment 2008, 2008
Development and verification of JAZZ1D: A stream temperature Model American Society of Agricultural and Biological Engineers Conference on 21st Century Watershed Technology Improving Water Quality and Environment 2008, 2008
