Pedro Rau

Forest carbon projects have become increasingly relevant for climate mitigation, yet integrated evidence regarding their territorial distribution, governance arrangements, carbon-market performance, and environmental integrity remains limited in Peru. This study provides an integrated assessment of carbon projects implemented between 2010 and 2026 using a mixed-methods approach that combined carbon-registry records, institutional documentation, supplementary project information, and the scientific literature. The analysis evaluated project scope, geographic distribution, governance structures, land tenure, carbon-credit dynamics, co-benefits, and integrity-related risks. The results indicate that Peru’s carbon project portfolio is strongly concentrated in forest-based mitigation pathways, particularly REDD+, ecological restoration, afforestation, and agroforestry initiatives located in the Amazon region. Most projects are implemented in Indigenous territories, private lands, and forest concessions, while private and Indigenous governance arrangements predominate over collaborative or multi-stakeholder models. Patterns of carbon-credit generation and retirement indicate substantial participation in voluntary carbon markets, although market activity is highly concentrated in a small number of large Amazonian REDD+ projects. Furthermore, projects reported biodiversity conservation, ecological restoration, livelihoods, and capacity-building benefits, while concerns related to additionality, leakage, permanence, safeguard implementation, and market transparency persist. Overall, the findings suggest that the long-term effectiveness and credibility of forest carbon projects depend not only on carbon performance but also on governance quality, environmental integrity, territorial rights, transparency, and equitable benefit-sharing mechanisms.

Climate change disproportionately affects mountain river basins, driving cryospheric changes and altering their hydrology. This has detrimental impacts on water resources, accentuating the need for robust adaptation strategies. Traditional engineering approaches can provide buffering capacity but are associated with high costs and limited flexibility. At the same time, local, small scale water management practices are gaining attention, yet evidence on their effectiveness remains limited. We evaluate the adaptation potential of common local practices, that is, headwater grassland regeneration, small surface storage, and artificial recharge, in the Vilcanota‐Urubamba system, Peru. We find that, if properly managed, these interventions can substantially contribute to seasonal and interannual hydrological buffering and dry season water availability. However, when implemented in isolation, they are unlikely to fully offset climate impacts. Our results support the design of catchment‐scale intervention portfolios for adaptation planning, with a combination of large, centralized infrastructure and distributed local interventions likely to provide the most effective solution.

A process diagram illustrating the steps followed for the modeling inputs and methodology, as well as the findings. These include the intensification of streamflow seasonality and the projected moderate to high long-term water stress in the Higueras River basin. Climate change threatens water availability in semi-arid Andean watersheds, where cities such as Huánuco (Peru) rely primarily on surface water for urban supply. This study evaluates future changes in water availability in the Higueras River Basin by integrating projections from 22 CMIP5 Global Climate Models (GCMs), Bias Correction, the GR2M hydrological model, population growth projections, and the Water Stress Index (WSI). This integrated framework addresses a gap in previous Andean studies by integrating climate projections, hydrological modeling, and urban water demand. Future water demand was estimated assuming a 2.59% annual population growth rate and a per-capita demand of 220 liters/person/day. Streamflow was simulated for 2003–2019 and projected for the short (2020–2036), medium (2037–2053), and long term (2054–2070) under RCP4.5 and RCP8.5 scenarios. Results show water surpluses during the short term, whereas deficits emerge in August and September during the medium-term (up to 0.31 m3/s) and intensify during July–September in the long term, reaching 1.10 m3/s in August under RCP8.5. The WSI also indicates a transition from low to moderate/high water stress after 2065, especially under RCP4.5. These findings highlight the urgency for adaptive water management and planning in Andean cities reliant on surface water.

Sedimentation is eroding the water security of reservoirs in hydrologically active basins: the Poechos reservoir (Peru) has lost 62% of its original 887.7 hm³ capacity in 48 years, yet its Elevation–Area–Volume (EAV) curve is refreshed only by bathymetric surveys at decade-plus intervals, compromising flood regulation and the water supply for over 100,000 ha of farmland. To close this gap, we propose an integrated, low-cost, fully reproducible framework that reconstructs the EAV curve from freely available satellite data: Sentinel-1 SAR (287 acquisitions, 2021–2026), PlanetScope imagery as ground truth (23 dates), and Surface Water and Ocean Topography (SWOT) altimetry (53 validated passes, 2023–2026). Water surfaces were delineated with a deep learning segmentation model (Feature Pyramid Network with an InceptionV4 encoder), selected among nine architecture–encoder combinations and calibrated to a 0.64 decision threshold, achieving a 90.66% Intersection over Union (IoU) and a 95.10% F1 score; a stochastic quantile mapping algorithm then asynchronously coupled the area and elevation series. The resulting EAV curve matched daily operational records from Peru’s National Water Authority (ANA) with high precision (NSE = 0.94, R² = 0.96, and RMSE = 25.93 hm³); the residual bias (BIAS = −11.23 hm³) reflects active sedimentation unaccounted for in the official curve. This bias peaked at an accumulated deficit of 24.5 hm³ during the 2023–2024 hydrological year (3.5 hm³/year), of which up to 19.6 hm³ is attributed to the 2023 Yaku cyclone as a phenomenologically scaled upper-bound estimate (9.8–19.6 hm³ across 40–80% attribution fractions), since SWOT was not yet operational during the event. Updating every 21 days under any weather and requiring no new field campaigns beyond the baseline bathymetric anchor, the trained ensemble was further transferred zero-shot to three additional reservoirs (San Lorenzo, Tinajones, and Gallito Ciego), demonstrating a scalable path from infrequent static assessments to near-continuous, dynamic monitoring of water storage.

Mountain headwaters in the tropical Andes are vital for regional water security, yet the extensive Puna grassland biome remains largely understudied. To help address this gap, we employed a paired‐catchment design in two Peruvian Puna catchments and used high‐resolution hydrometric data, over the period [2012–2014] at hourly time‐step, to investigate controls on hydrological partitioning and subsurface storage. Our findings provide a field‐based perspective on the classic ‘sponge versus pipe’ paradox by showing that peat‐forming wetlands (bofedales) perform a dual hydrological role. Their saturated surfaces act as efficient ‘pipes’ that enhance event runoff, while their porous subsurface provides event‐scale buffering that dampens hydrograph recessions, defining them as seasonal buffers rather than long‐term dry‐season stores. Streamflow recession analysis further supports a dual‐reservoir conceptualization, in which infiltrated water is partitioned between a shallow system connected to local streamflow and a deeper system linked to regional groundwater recharge. The catchment with greater apparent percolation capacity produced lower annual water yield, consistent with a ‘leaky’ catchment interpretation involving inter‐catchment groundwater flow that bypasses the topographic outlet. Our comparison also suggests that the naturally flashier response of this catchment may be further accentuated by more intensive grazing, although this land‐use signal should be interpreted as secondary to hydrogeomorphic controls. Overall, the results indicate that hydrological functioning is organized hierarchically: subsurface and surficial hydrogeomorphic setting controls the distribution of bofedales and flow paths, while land use modulates the resulting response. This perspective reframes Puna headwater catchments as three‐dimensional systems characterized by a trade‐off between local streamflow resilience and regional aquifer recharge, underscoring the need to preserve bofedal connectivity and mitigate soil‐degrading land uses.

Flood monitoring in dry tropical basins, such as the Tumbes River (Peru), faces critical challenges due to persistent cloud cover that restricts the operability of optical sensors during extreme events, coupled with the operational gap between satellite products and conventional hydrological monitoring. To overcome these limitations, this research developed a comprehensive methodological framework in Google Earth Engine that unifies automated image thresholding and Sentinel-1 SAR time series analysis for flood detection and the estimation of early warning thresholds. The Bmax Otsu and Edge Otsu algorithms were evaluated, previously calibrated using high-resolution imagery (PlanetScope) as reference data, topographically constrained by the HAND (Height Above the Nearest Drainage) model, and validated against established change detection algorithms. The analysis of seven hydrological events between 2017 and 2024 confirmed the statistical superiority of Bmax Otsu; although both methods achieved high overall accuracy (Bmax 95.8% versus Edge 95.7%), Bmax Otsu outperformed Edge Otsu in spatial consistency (Kappa 66.1% vs. 63.7%; IoU 45.6% vs. 45.0%). Based on this, a time series analysis was applied to discriminate permanent water bodies and isolate flood dynamics. Subsequently, the functional discharge–impact response was evaluated by linking the instantaneous flood extent captured by the SAR overpasses to their corresponding peak discharges. Validated against official INDECI damage reports, it was determined that significant impacts begin at an activation threshold of 743.49 m³/s (151 flooded ha, 157 affected inhabitants) and scale linearly up to extreme peak events of 1629.02 m³/s, compromising 1234 agricultural ha and 749 inhabitants. This methodology provides a validated, low-cost tool to translate SAR observations into critical thresholds for early warning systems in data-scarce regions.

The Rimac River Basin supplies drinking water to more than ten million people in Lima, Peru, yet its hydrological regulation capacity is increasingly constrained by land degradation, with over 35% of the basin lacking vegetation cover. Nature-based solutions implemented through conservation and restoration of natural ecosystem offer a potential complement to grey infrastructure, although their basin-scale hydrological benefits remain scantily quantified. This study proposes an inverse assessment framework that uses future degraded states as hydrological benchmarks to quantify redistributed water as a proxy for the volumetric benefits that conservation or restoration could potentially provide. Degraded Andean shrubland and grasslands were identified and prioritized using the RIOS investment assessment tool, resulting in three degradation portfolios (2826; 6566; and 10,720 ha) for the 2011–2016 period. Their hydrological responses were then simulated using the SWAT model, with a focus on dry-season dynamics. The model achieved a Kling Gupta Efficiency of 46.9% and a seasonally targeted Nash–Sutcliffe efficiency of 70% during the dry season, ensuring that despite the basin anthropization, the low flow dynamics key for water security are reliably represented. Water availability indicators and flow-duration curve metrics were applied to evaluate changes in hydrological regulation. Results show that all portfolios increased dry-season streamflow relative to baseline conditions, with the largest portfolio producing a 2.39% increase, equivalent to approximately 4 hm³ during the critical June–August period. These findings indicate that degradation alters flow redistribution within the basin water cycle and suggest that conservation or restoration may reverse these effects. The intermediate and large portfolios provided the most informative benchmarks, supporting spatially explicit decision making for basin-scale water regulation.

Variabilité du régime des précipitations, des débits et des bilans hydriques le long du versant pacifique péruvien : influence du phénomène ENSO et sensibilité au changement hydroclimatique: La variabilité climatique et les événements extrêmes associés comme le phénomène El Niño (ENSO) représentent les épisodes les plus difficiles à gérer dans le Versant Pacifique Péruvien. En outre, une préoccupation croissante sur la disponibilité en eau a lieu depuis les années 1970s. Une documentation approfondie des régimes de précipitations et des débits est un élément clé de tout plan de gestion de l'eau et notre recherche est la première étude sur la variabilité hydroclimatique à l'échelle mensuelle et annuelle dans la zone d'étude au cours des quatre dernières décennies (période 1970-2010). Tout d'abord, un traitement de base de données exhaustif a été effectué pour surmonter certaines limitations et notamment celles liées aux conditions géographiques des Andes. Deuxièmement, le régime des précipitations a été étudié avec une approche de régionalisation liée aux conditions de séries temporelles non stationnaires. Une méthode mixte associant la méthode des clusters k-means et la méthode du vecteur régional a été proposée. Neuf régions ont été identifiées avec des régimes homogènes de précipitation tenant compte d'un gradient latitudinal et altitudinal. Un bilan hydroclimatique a ensuite été fait à l'échelle de bassin versant, abordant la problématique du climat et de l'anthropisation et leurs influences potentielles sur les séries chronologiques hydroclimatiques. Le cadre théorique de Budyko-Zhang a été utilisé et a permis d'identifier 11 des 26 bassins versants à faible influence climatique et anthropique (i.e. des conditions quasi-naturelles). Le régime des débits a ensuite été étudié pour ces conditions et une extension pour l'ensemble des 49 bassins versants de la zone d'étude a été effectuée. Un modèle hydrologique régional est proposé via deux modèles conceptuels agrégés à l'échelle de temps annuelle et mensuelle (GR1A et GR2M respectivement). Un test d'échantillonnage différentiel (DSST) a été utilisé pour améliorer la robustesse de la modélisation par rapport aux conditions climatiques contrastées entre années sèches et humides dans les conditions semi-arides. Enfin, la portée de la thèse couvre (1) une revisite de la relation ENSO/précipitation en prenant en compte les neuf régions identifiées et de plusieurs indices ENSO afin de discriminer l'influence des deux types d'El Niño (El Niño du Pacifique Est EP et du Pacifique Central CP) ainsi que l'influence de la variabilité atmosphérique (i.e. l'oscillation Madden et Julian) et aux conditions océaniques régionales. La méthodologie proposée consiste en l'analyse des composantes principales, ondelettes et de cohérence, les corrélations glissantes et l'analyse de la covariance spatiale afin de mettre en évidence la modulation décennale significative du phénomène ENSO ainsi que sa croissance à partir des années 2000s où la relation ENSO/précipitations s'inverse par rapport à la décennie précédente. Les deux modes de co-variabilité dominants entre la température superficielle de la mer dans le Pacifique tropical et les neuf régions montrent des caractéristiques dominantes de l'influence de l'ENSO: une augmentation des précipitations sur les régions aval dans le nord pendant El Niño EP et une diminution des précipitations sur les régions amont le long des Andes lors des événements El Niño CP. (2) La sensibilité au changement hydroclimatique est explorée via l'analyse des tendances hydroclimatiques comme indicateurs de changement de l'hydroclimatologie régionale. Les résultats montrent un réchauffement important dans la zone d'étude avec une moyenne de 0,2°C par décennie. En outre, les changements dans les trajectoires dans l'espace de Budyko (i.e. direction et amplitude) ont révélé que six bassins versants étaient sensibles à la variabilité du climat (i.e. probablement avec une grande sensibilité au climat futur) et aux changements d'utilisation du sol et où les précipitations et la température sont les facteurs prépondérants du changement de ces environnements.

Watersheds provide fundamental hydrological ecosystem services for human well-being and the environment, such as water provisioning, hydrological cycle regulation, and erosion control; however, these services face increasing anthropogenic and climatic pressures. This study assessed individual and combined impacts on the hydrological functionality of the Piuray–Ccorimarca watershed (Cusco, Peru) using a calibrated Soil and Water Assessment Tool (SWAT) model, analyzing water yield, soil water storage, and sediment transport across 20 scenarios. An ensemble of 10 Coupled Model Intercomparison Project Phase 6 (CMIP6) models with bias correction was implemented, integrated with land transformation projections contemplating urban expansion associated with airport development and forest recovery through Payment for Ecosystem Services mechanisms. The results reveal climate change as the dominant driver, generating water yield increases and soil water content improvements primarily due to evapotranspiration decoupling that increases the runoff coefficient. In contrast, land use change produces substantially smaller hydrological effects but critically intensifies sediment yield. Spatial vulnerability analysis identified eight persistently critical sub-basins (20.5% of area) where soil water content emerged as the dominant limiting factor. These findings establish a clear management hierarchy prioritizing climate adaptation over land use interventions, with differentiated strategies required for critical zones demanding structural interventions versus non-critical areas amenable to flexible conservation approaches.