Christian Birkel

Christian Birkel
University of Costa Rica | UCR · Department of Geography

PhD

About

181
Publications
45,895
Reads
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3,400
Citations
Introduction
My research broadly focuses on catchment hydrology and the measurement and modelling of streamflow generation and biogeochemical processes. The basic aim is to better understand catchment functioning and the great variability of hydrological behaviours across different temporal and spatial scales. Insights from my research can be applied to assess the impacts of stream regulation and environmental change on the quality and quantity of surface waters.
Additional affiliations
August 2016 - present
University of Costa Rica
Position
  • Professor
August 2014 - July 2016
University of Costa Rica
Position
  • Professor
November 2010 - August 2014
University of Aberdeen
Position
  • PostDoc Position

Publications

Publications (181)
Article
Using conservative tracers to aid conceptual rainfall–runoff modelling has gained momentum over the past decade. Tracer data have been invaluable in providing rich insights into runoff sources, flow paths and water age that cannot be established by simple rainfall–runoff dynamics alone. Accordingly, this has provided a focus for fertile dialogue be...
Article
Full-text available
We used a relatively simple two-layer, coupled hydrology-biogeochemistry model to simultaneously simulate streamflow and stream DOC concentrations in a small, lead and arsenic contaminated upland peat catchment in northwestern Germany. The model procedure was informed by an initial data mining analysis, in combination with regression relationships...
Article
Pristine tropical forests play a critical role in regional and global climate systems. For a better understanding of the eco-hydrology of tropical "evergreen" vegetation, it is essential to know the partitioning of water into transpiration and evaporation, runoff and associated water ages. For this purpose, we evaluated how topography and vegetatio...
Article
Full-text available
Our understanding of how wet-dry tropical catchments process water and solutes remains limited. In this study, we attempt to gain understanding of water and dissolved organic carbon (DOC) transport, storage and mixing in a 126 km2 catchment of northern Australia. We developed a coupled, tracer-aided, conceptual rainfall-runoff model (SAVTAM) that s...
Article
Full-text available
Purpose Volcanic, humid tropical landscapes are characterized by short-term geomorphic transformations due to volcanism and seismic activity, landslides, and other frequent mass movements. These landscape-forming processes are amplified by high temperatures, high annual precipitation rates, and intense rainstorms. The latter can result in significa...
Article
El conocimiento global de las consecuencias del cambio de vegetación y uso de suelo en las fases del ciclo hidrológico y la calidad del suelo aún está en ciernes. Esta tarea es particularmente desafiante en las regiones tropicales donde las tasas de deforestación alcanzan los niveles máximos reportados y el monitoreo es limitado. Tal es el caso de...
Preprint
Full-text available
Tracer-aided studies to understand source water partitioning in tropical ecosystems are limited. Here we report dry season source water partitioning in five unique ecosystems distributed across Costa Rica in altitudinal (<150-3,400 m asl) and latitudinal (Caribbean and Pacific slopes) gradients: evergreen and seasonal rainforests, cloud forest, Pár...
Article
Stable water isotopes are invaluable in helping understand catchment functioning and are widely used in experimental catchments, with higher frequency data becoming increasingly common. Such datasets incur substantial logistical costs, reducing their feasibility for use by decision makers needing to understand multi-catchment, landscape-scale funct...
Article
Monitoring solute fluxes in water quality studies is essential to reveal potential ecosystem disturbances, and is particularly important in Andean headwater catchments as they are the main sources of water for downstream populations. However, such studies have mainly focused on organic matter and nutrients, disregarding other solutes that can threa...
Article
Full-text available
Streamflow simulation across the tropics is limited by the lack of data to calibrate and validate large-scale hydrological models. Here, we applied the process-based, conceptual HYPE (Hydrological Predictions for the Environment) model to quantitatively assess Costa Rica's water resources at a national scale. Data scarcity was compensated for by us...
Article
Full-text available
There is still limited understanding of where stream water originates, their flow paths, how water sources mix, and for how long water transits montane tropical catchments. Here, we used a simple gamma convolution integral model (GM), ensemble hydrograph separation (EHS) and a tracer‐aided model (TAM) to assess runoff generation, mixing processes a...
Article
Full-text available
Droughts are causing severe damages to tropical countries worldwide. Although water abundant, their resilience to water shortages during dry periods is often low. As there is little knowledge about tropical drought characteristics, reliable methodologies to evaluate drought risk in data scarce tropical regions are needed. We combined drought hazard...
Article
Better drought preparedness is critically needed in the Central American Dry Corridor (CADC). Seasonal forecasts can be used to build this preparedness but need localized evaluations to ensure they are relevant and useful. This study provides a CADC-focused assessment of the SEAS5 seasonal forecasting system produced by the European Centre for Medi...
Article
Rationale: New methods to measure stable isotopes of soil and tree water directly in the field enable us to increase the temporal resolution of obtained data and advance our knowledge on the dynamics of soil and plant water fluxes. Only few field applications exist. However, these are needed to further improve novel methods and hence exploit their...
Preprint
Understanding how droughts propagate through the hydrological cycle from precipitation to streamflow and groundwater is important for improving water and risk management policies. At the catchment scale, the analysis of drought propagation and classification into drought types is usually done manually, which can be time consuming and difficult to r...
Article
Full-text available
River floods frequently occur when tropical cyclones hit land. Nonetheless, systematic, long-term discharge data remain rather scarce in many tropical countries, which prevents proper analysis of peak discharges occurring during floods. The Térraba catchment is the biggest and most dynamic catchment in Costa Rica. In this study, we developed region...
Article
Efforts to protect tropical ecosystems aim at implementing biological corridors across the national territory of Costa Rica. However, potential near-future climate change challenges the effectiveness of such conservation measures. For this purpose, we developed near-future climate change scenarios at high spatial resolution using open-access global...
Article
Full-text available
Increasing rates of biodiversity loss are adding momentum to efforts seeking to restore or rewild degraded landscapes. Here, we investigated the effects of natural forest regeneration on water flux partitioning, water ages and hydrological connectivity, using the tracer-aided ecohydrological model EcH2O-iso. The model was calibrated using ~3.5 year...
Article
Full-text available
Monitoring the temporal variation of solute concentrations in streams at high temporal frequency can play an important role in understanding the hydrological and biogeochemical behavior of catchments. UV-Visible spectrometry is a relatively inexpensive and easily used tool to infer those concentrations in streams at high temporal resolution. Howeve...
Preprint
Full-text available
Streamflow simulation across the tropics is limited by the lack of data to calibrate and validate large-scale hydrological models. Here, we applied the process-based, conceptual HYPE (Hydrological Predictions for the Environment) model to quantitively assess Costa Rica’s water resources at a national scale. Data scarcity was compensated using adjus...
Article
Full-text available
Global bottled water consumption has largely increased (14.35 billion gallons in 2020) [1-5] during the last decade since consumers are demanding healthier and safer forms of rehydration. Bottled water sources are normally labeled as mountainous and pristine mineral springs (fed by rainfall and snow/glacier melting processes), deep groundwater well...
Article
Full-text available
Isotopes are increasingly used in rainfall‐runoff models to constrain conceptualisations of internal catchment functioning and reduce model uncertainty. However, there is little guidance on how much tracer data is required to adequately do this, and different studies use data from different sampling strategies. Here, we used a seven‐year time serie...
Article
Spatially and seasonally‐distributed information on transpiration (T) fluxes is limited in the tropics. Here, we applied a coupled isotope mass balance model to separate water fluxes of T and evapotranspiration (ET) from precipitation (P). The mean annual T was estimated at a resolution of 100m for Costa Rica (51100 km²) and a partitioning of month...
Preprint
Full-text available
Abstract: Increasing rates of biodiversity loss are adding momentum to efforts seeking to restore or rewild degraded landscapes. Here, we investigated the effects of natural forest regeneration on water flux partitioning, water ages and hydrological connectivity, using the tracer aided ecohydrological model EcH2O-iso. The model was calibrated using...
Article
Full-text available
The cause-effect relationship and rates of change of suspended sediment dynamics at catchment scales in the tropics remains poorly understood. This research used a chrono-sequence of remotely sensed land use and historical hydrometric data from 1985 to 2001 in three tropical streams of Mexico to analyze the temporal dynamics of land-use change and...
Article
Full-text available
The impacts of forest conversion on runoff generation in the tropics have received much interest, but scientific progress is still hampered by challenging fieldwork conditions and limited knowledge about runoff mechanisms. Here, we assessed the runoff generation, flow paths and water source dynamics of a pristine rainforest catchment in Costa Rica...
Article
Full-text available
The seasonally-dry tropics of northern Costa Rica are characterized by recurrent drought events with negative socioeconomic impacts on a vulnerable population. Scarce hydroclimatic observational data constraints reasonable water management and often results in water scarcity issues. This study analyses hydrological drought situations using freely a...
Presentation
Full-text available
In-situ monitoring of the temporal variation of solutes' (nutrients and metals) concentrations as tracers can enhance knowledge of the hydrological and biogeochemical behavior of catchments. UV-Visible spectrometry represents a relatively inexpensive and easily used tool to explore how those concentrations vary in time at high temporal frequency. H...
Preprint
Full-text available
Droughts are causing severe damages to water abundant tropical countries worldwide. Their resilience to water shortages tends to be low, often due to a lack of water infrastructure. Moreover, drought characteristics and risk in tropical catchments are poorly understood, which makes it difficult to select adequate adaptation measures. Thus, reliable...
Article
Full-text available
Tropical regions cover approximately 36% of the Earth's landmass. These regions are home to 40% of the world's population, which is projected to increase to over 50% by 2030 under a remarkable climate variability scenario often exacerbated by El Niño Southern Oscillation (ENSO) and other climate teleconnections. In the tropics, ecohydrological cond...
Article
Full-text available
The magnitude of the terrestrial carbon (C) sink may be overestimated globally due to the difficulty of accounting for all C losses across heterogeneous landscapes. More complete assessments of net landscape C balances (NLCB) are needed that integrate both emissions by fire and transfer to aquatic systems, two key loss pathways of terrestrial C. Th...
Article
Full-text available
Páramos, a neotropical alpine grassland‐peatland biome of the northern Andes and Central America, play an essential role in regional and global cycles of water, carbon, and nutrients. They act as water towers, delivering water and ecosystem services from the high mountains down to the Pacific, Caribbean, and Amazon regions. Páramos are also widely...
Article
Water use by anthropogenic activities in the face of climate change invokes a better understanding of headwater sources and lowland urban water allocations. Here, we constrained a Bayesian mixing model with stable isotope data (2018–2019) in rainfall (N = 704), spring water (N = 96), and surface water (N = 94) with seasonal isotope sampling (wet an...
Article
Full-text available
Fisheries scientists need to understand the relationships between river temperature, discharge and production of juvenile salmonids to inform evidence‐based management and regulation of rivers, and to understand the potential effects of climate change. These relationships can be determined by characterising interannual variability in abundance and...
Article
Headwaters are generally assumed to contribute the majority of water to downstream users, but how much water, of what quality and where it is generated are rarely known in the humid tropics. Here, using monthly monitoring in the data scarce (2,370 km²) San Carlos catchment in northeastern Costa Rica, we determined runoff‐area relationships linked t...
Presentation
Full-text available
Se presentó la estructura de un modelo de pronóstico hidrológico determinístico a corto plazo (15 días en el futuro) usando herramientas open-source. El sistema propuesto pretende incorporar una infraestructura de bajo costo económico, eficiente en costo computacional y bajo consumo de datos para los usuarios finales. El sistema pretende utilizar b...
Preprint
Full-text available
Abstract. Iodine is an essential trace element for all mammals and its bioavailability in terrestrial systems depends on its accumulation in soils but also on its release into the aquatic system. In tropical systems retention and mobilization of iodine in soils and related concentrations in streamflow are poorly understood. We, therefore, investiga...
Article
The accurate representation of spatio-temporal patterns of precipitation is an essential input for numerous environmental applications. However, the estimation of precipitation patterns derived solely from rain gauges is subject to large uncertainties. We present the Random Forest based MErging Procedure (RF-MEP), which combines information from gr...
Article
Tropical regions are frequently affected by intense floods causing substantial human and economic losses. A proper management of floods and the prevention of disasters is, however, often hampered by a generalized paucity of systematic discharge measurements, which in turn renders any assessment of the frequency and magnitude of extreme floods chall...
Article
Full-text available
The riverine export of carbon is expected to be driven by changes in connectivity between source areas and streams. Yet we lack a thorough understanding of the relative contributions of different water sources to the dissolved carbon flux, and of the way these contributions vary with seasonal changes in flow connectivity. Here we assess the tempora...
Chapter
This short article on rainfall-runoff modeling attempts to give a brief overview on a rather vast topic in the hydrological sciences. We, unfortunately, cannot go into details of any special branch of modeling. Nonetheless, we rather settle on introductory materials that might offer guidance for hydrology, engineering, geography and environmental s...
Article
Full-text available
The availability of large tracer data sets opened up the opportunity to investigate multiple source contributions to a mixture. However, the source contributions may be uncertain and, apart from Bayesian approaches, to date there are only solid methods to estimate such uncertainties for two and three sources. We introduce an alternative uncertainty...
Article
Full-text available
In this special issue of Hydrological Processes, we showcase the variety of ongoing research in catchments of the hydrometeorological, geomorphological and biogeographical mega-diverse region of Latin America and the Caribbean (LAC). The papers of this special issue address hydrological processes that regulate storage, mixing, and fluxes of water...
Article
Full-text available
The Mesoamerican and Caribbean (MAC) region is characterized by tropical cyclones (TCs), strong El Niño-Southern Oscillation events, and climate variability that bring unique hazards to socio-ecological systems. Here we report the first characterization of the isotopic evolution of a TC (Hurricane Otto, 2016) in the MAC region. We use long-term dai...
Article
Full-text available
Dissolved organic carbon (DOC) transport and export from headwater forests into freshwaters in highly dynamic tropical catchments are still understudied. Here we present a DOC analysis (2017) in a pristine and small (~2.6 km²) tropical catchment of Costa Rica. Storm flows governed a rapid surface and lateral allochthonous DOC transport (62.2% of th...
Preprint
Full-text available
Dissolved organic carbon (DOC) transport and export from headwater forests into freshwaters in highly dynamic tropical catchments are still understudied. Here, we present a DOC analysis (2017) in a pristine and small (~2.6 km 2) tropical catchment of Costa Rica. Storm flows governed a rapid surface and lateral allochthonous DOC transport (62.2% of...
Article
Full-text available
The availability of large tracer data sets opened up the opportunity to investigate multiple source contributions to a mixture. However, the source contributions may be uncertain and apart from Bayesian approaches to estimate such source uncertainty only sound methods for two and three sources. We expand these methods developing an uncertainty esti...
Conference Paper
Full-text available
Torrential floods are a frequent hazard in the General River in Costa Rica, and have caused disasters along its flood-plain, for the last time during the 2017 rainy season. Coping with future flood disasters requires an understanding of the frequency and magnitude of flood events. However, as in many areas in Costa Rica and Central America, the Gen...
Conference Paper
Full-text available
The scientific evidence base for understanding how rainfall is generated and partitioned into different hydrological processes in Costa Rica and the wider humid tropics is limited due to the scarcity of basic hydrological data. This makes it difficult to conceptualize the dominant runoff generation processes and severely hinders our ability to trac...
Conference Paper
Full-text available
Northern Costa Rica faces diverse environmental problems, including the contamination of surface and groundwater, which is partly caused by the intensive pineapple and sugar cane monocultures in this area. Together with poorly controlled and enforced environmental management mainly caused by a lack of monitoring data already triggered conflicts in...
Conference Paper
Full-text available
A complete understanding of hydrology and solute dynamics of tropical humid catchments requires spatio-temporal tracking of fluxes, storage, mixing and flow paths. Additionally, we lack detailed knowledge about how precipitation is partitioned into distinct "green and blue" hydrological processes and their respective transit and residence times. Pa...
Article
Full-text available
High-elevation tropical grassland systems, called Páramo, provide essential ecosystem services such as water storage and supply for surrounding and lowland areas. Páramo systems are threatened by climate and land use changes. Rainfall generation processes and moisture transport pathways influencing precipitation in the Páramo are poorly understood...
Article
Full-text available
Reading landscapes and developing calibration-free runoff generation models that adequately reflect land surface heterogeneities remains the focus of much hydrological research. In this study, we report a novel and simple topography-driven runoff generation parameterization – the HAND-based Storage Capacity curve (HSC), which uses a topographic ind...
Article
Central America is a region vulnerable to hydrometeorological threats. Recently, the impacts of droughts caused higher economic losses in comparison to e.g. floods and landslides. This study focuses on the spatio‐temporal behaviour of cumulative rainfall deficits across Central America attempting to provide an historical context to the most recent...
Article
The influence of forest cover on dry‐season stream flow in the humid tropics has been of enduring interest to eco‐hydrologists and policy makers. We used data from eight nested gauging stations in the Terraba river basin (4774 km2) of Costa Rica to demonstrate how a Bayesian regression approach could be applied to test hypotheses on “infiltration‐e...
Article
Full-text available
Tropical high-elevation lakes are considered sentinels of global climate change. This work characterizes the hydrological conditions of tropical alpine glacial lakes located in the highlands of Chirripó, Costa Rica, using a unique data set of water stable isotopes (δ2H and δ18O) in precipitation, stream water, and lake water between September 2015...