Jan Feyen

University of Cuenca | UC · Departamento de Recursos Hídricos y Ciencias Ambientales

The years 2020 and 2021 will, without doubt, be remembered as corona virus years, but also as the years that everything changed. Today we think that we conquered the coronavirus, but isn’t it more realistic to believe that we have partial control over the virus through the vaccination process? Notwithstanding the vaccination, on the 4th of October...

The effects of global warming are becoming more visible every day. Droughts, floods, and heat waves that used to occur once every 10 years now occur 4-6 times a decade, increasingly threatening planet Earth and the world's food supply. Climate changes and ongoing conflicts are contributing to a worsening global hunger crisis. If current trends cont...

The year 2021 is nearing its end when the online version of the journal MASKANA 12(2) is published. 2021, means that already one-fifth of the 21st century has passed. Since 2000 raised the world population from 6.1 to 7.9 billion, or 29.5%. Different models predict that the world population in 2030, the year that the world leaders in Glasgow (UK) d...

Worldwide, machine learning (ML) is increasingly being used for developing flood early warning systems (FEWSs). However, previous studies have not focused on establishing a methodology for determining the most efficient ML technique. We assessed FEWSs with three river states, No-alert, Pre-alert and Alert for flooding, for lead times between 1 to 1...

Flood Early Warning Systems (FEWSs) using Machine Learning (ML) has gained worldwide popularity. However, determining the most efficient ML technique is still a bottleneck. We assessed FEWSs with three river states, No-alert, Pre-alert, and Alert for flooding, for lead times between 1 to 12 hours using the most common ML techniques, such as Multi-L...

Extreme runoff modeling is hindered by the lack of sufficient and relevant ground information and the low reliability of physically-based models. The authors propose to combine precipitation Remote Sensing (RS) products, Machine Learning (ML) modeling, and hydrometeorological knowledge to improve extreme runoff modeling. The approach applied to imp...

Ranking of universities has become over the past two decades a common practice and the institutions’ interest in ranking at national and international level is only increasing. Universities, analogous to the industry, increasingly use their ranking to highlight their quality and excellence, with the objective to increase its visibility leading to a...

Research journals disseminate scholarly work to the scientific community and by doing so fulfill a fourfold role, namely sharing knowledge with colleagues for evaluation and verification, serving as a basis for the generation of new knowledge, assisting the society in turning it into a better one, and for the archiving of research work. An immense...

University development in Ecuador was relatively uncoordinated; it was not until the early 1970s that further progress was enshrined in the national education plan. Even then, hardly any attention was paid to research. Additionally, the political, social, and economic development in the following decades, along with the fairly autonomous and uncoor...

Will the education sector be immune from the financial debacle caused by Covid-19? The impact will be acute, universities in the United Kingdom, for example, has recognized serious financial challenges ahead and London Economics is indicating a potential sector-wide loss of tuition fees of 2.6 billion pounds next year. This will be hard for the pri...

Accurate determination of the water retention curve (WRC) of a soil is essential for the understanding and modelling of the subsurface hydrological, ecological, and biogeochemical processes. Volcanic ash soils with andic properties (Andosols) are recognized as important providers of ecological and hydrological services in mountainous regions worldw...

Despite its importance, is evapotranspiration poorly studied in páramo ecosystems. This study assesses the performance of 30 models, including 21 empirical models, (radiation-, temperature-, combination- and mass transfer-based), 8 artificial neural network models (ANNs), and 1 multivariate adaptive regression spline (MARS) model for the estimation...

Efforts to correct precipitation measurements have been ongoing for decades, but are scarce for tropical highlands. Four tipping-bucket (TB) rain gauges with different resolution that are commonly used in the Andean mountain region were compared—one DAVIS-RC-II, one HOBO-RG3-M, and two TE525MM TB gauges (with and without an Alter-Type wind screen)....

Por décadas se ha trabajado para corregir las medidas de precipitación, sin embargo estos esfuerzos han sido esca-sos en zonas tropicales montañosas. Cuatro pluviómetros de balancín (TB), con distinta resolución y comúnmenteutilizados en las montañas de los Andes, fueron comparados en este estudio: un DAVIS-RC-II, un HOBO-RG3-M, ydos TE525MM (con y...

Andosol soils formed in volcanic ash provide key hydrological services in montane environments. To unravel the subsurface water transport and tracer mixing in these soils we conducted a detailed characterization of soil properties and analyzed a 3‐year data set of sub‐hourly hydrometric and weekly stable isotope data collected at three locations al...

The definition of wake-up call is something that alerts people to an unsatisfactory situation and drives them to remedy it. In this sense, today's publication of QS World University Rankings 2020 can be seen as a wake-up call for Ecuador’s universities, SENESCYT, CACES and CES. First, the article assesses the performance of Ecuador’s universities u...

Andean ecosystems provide important ecosystem services including streamflow regulation and carbon sequestration, services that are controlled by the water retention properties of the soils. Even though these soils have been historically altered by pine afforestation and grazing, little research has been dedicated to the assessment of such impacts a...

We demonstrated the great value of spatially distributed and temporally high-resolution hydro-chemical data to enhance knowledge about the intra-catchment variability of flow processes and the runoff composition of individual storms in a tropical alpine (Páramo) ecosystem. In this study, water sources (rainfall, spring water, and water from soil la...

The relative importance of catchment's water provenance and flow paths varies in space and time, complicating the conceptualization of the rainfall-runoff response. We assessed the temporal dynamics in source areas, flow paths and age by End Member Mixing Analysis (EMMA), Hydrograph Separation (HS) and Inverse Transit Time Proxies (ITTPs) estimatio...

Este artículo presenta un análisis descriptivo y comparativo de la precipitación y la escorrentía de tres microcuencas andinas (entre 0.6 y 1 km2) empleando aproximadamente 8 años de información, con el objetivo de relacionar las diferencias en el comportamiento del caudal con el nivel de precipitación anual, la distribución mensual de la lluvia y...

English teachers in Ecuadorian universities, like teachers in many non-native English-speaking countries, face the challenge of dealing with uninterested, unmotivated students, even when intermediate proficiency of English is a basic requirement for graduation. As from the end of 2014, the Faculty of Psychology of the University of Cuenca modified...

The reliability of climate models depends ultimately on their adequacy in relevant real situations. However, climate in mountains, a very sensitive system, is scarcely monitored, making the assessment of global climate models (GCMs) projections problematic. This is even more critical for tropical mountain regions, where complex atmospheric processe...

To improve the current knowledge of the rainfall-runoff phenomena of tropical montane catchments, the usefulness of several hydrological indicators was explored on a nested cloud forest catchment (76.9 km2). The used metrics belong to five categories, respectively: base flow mean transit time, physicochemical properties of stream water, land cover,...

This article reports on a comparative study between the publication productivity of Ecuador’s leading Higher Education Institutions (HEIs) (as reported in the SCOPUS journal/proceedings database; https://www.elsevier.com/solutions/scopus) and the publication efforts of similar universities in South-America and Western Europe when those universities...

This article reports on a comparative study between the publication productivity of Ecuador’s leading Higher Education Institutions (HEIs) (as reported in the SCOPUS journal/proceedings database; https://www.elsevier.com/solutions/scopus) and the publication efforts of similar universities in South-America and Western Europe when those universities...

A laser-optical disdrometer served as reference to assess the absolute percent bias of calculated rainfall intensity using the data of different-resolution tipping-bucket rain gauges classically applied by climatologists and hydrologists in the Andean region. Additionally, the impact of the calculation method (tip counting versus cubic spline inter...

As a consequence of the remote location of the Andean páramo is knowledge on their hydrologic functioning limited, notwithstanding this alpine tundra ecosystem act as water towers for a large fraction of the society. Given the harsh environmental conditions in this region is year-round monitoring cumbersome, and it would be beneficially if the moni...

Downscaling improves considerably the results of General Circulation Models (GCMs). However, little information is available on the performance of downscaling methods in the Andean mountain region. The paper presents the downscaling of monthly precipitation estimates of the NCEP/NCAR reanalysis 1 applying the statistical downscaling model (SDSM), a...

This article states that the confrontational attitude between local communities pushed by lobbying groups, eventually with the support of local governments, and mining companies can be turned into a corporate communication and cooperation model. Several of the large mining companies recently adopted a corporate business model in which ample room is...

The Site Index is widely used in forestry to estimate site productivity. One of the limitations of this method is the multitude of site data, collected over a period of time, needed to derive the index. For regions with limited availability of those data, it will be an advantage to have an operational, low-cost predictor for site productivity. We t...

The Site Index is widely used in forestry to estimate site productivity. One of the limitations of this method is the multitude of site data, collected over a period of time, needed to derive the index. For regions with limited availability of those data, it will be an advantage to have an operational, low-cost predictor for site productivity. We t...

Precipitation event samples and weekly based water samples from streams and soils were collected in a tropical montane cloud forest catchment for 2 years and analyzed for stable water isotopes in order to understand the effect of sampling frequency in the performance of three lumped-parameter distribution functions (exponential-piston flow, linear-...

Stream and soil waters were collected on a weekly basis in a tropical montane cloud forest catchment for two years and analyzed for stable water isotopes in order to infer transit time distribution functions and to define the mean transit times. Depending on the water type (stream or soil water), lumped distribution functions such as Exponential-Pi...

Weekly samples from surface waters, springs, soil water and rainfall were collected in a 76.9 km2 mountain rain forest catchment and its tributaries in southern Ecuador. Time series of the stable water isotopes δ18O and δ2H were used to calculate mean transit times (MTTs) and the transit time distribution functions (TTDs) solving the convolution me...

A cross-sectional model, based on the two dimensional groundwater flow equation of Edelman, was applied at seven transects distributed over four geological cross sections to estimate groundwater heads and recharge from/or groundwater discharge to Lake Nasser. The lake with a length of 500 km and an average width of 12 km was created over the period...

This paper reports on a study that analyzed the research output of higher education systems in a select number of Latin American countries and its relationship to several socio-economic and technological success indicators. This was placed within a broader discussion of the changing role of the university in society. The study used the rankings of...

Weekly samples from surface waters, springs, soil water and rainfall were collected in a 76.9 km 2 mountain rain forest catchment and its tributaries in southern Ecuador. Time series of the stable water isotopes δ 18 O and δ 2 H were used to calculate mean transit times (MTTs) and the transit time distribution functions (TTDs) solving the con-5 vol...

The time domain reflectometry (TDR) technique was evaluated as a viable method for quick and accurate characterization of the solute transport parameters in controlled laboratory conditions. The method is able to measure steady-state solute breakthrough curves of inert solutes in soil columns. Transport of a solute was monitored in a column uniform...

The four-parameter mobile-immobile model (MIM) is often used to describe solute transport processes in aggregated porous media by assuming no advective solute transport in the aggregates or immobile zone and a first-order kinetic diffusion transport process between the mobile and immobile zones. When the concentration in the immobile zone reaches a...

The performance of published pedotransfer functions was evaluated in terms of predicted soil water content, pressure heads, and drainage fluxes for a layered profile. The pedotransfer functions developed by Vereecken et al. (1989), Vereecken et al. (1990) were used to determine parameters of the soil hydraulic functions θ(h) and K(h) which were the...

Time-domain reflectometry (TDR) was used to monitor solute breakthrough curves (BTC's) in 30 saturated undisturbed soil columns collected along a 35-m-long transect in the field. The BTC's were obtained by relating the bulk soil electrical conductivity, ECa, to the relative concentration of a KCl solute pulse applied to the soil surface. Values of...

Saturated hydraulic conductivity (K-S) is an important soil hydraulic parameter for it establishes a limit on the rate of water and solute transmission through soil. However, its determination in the laboratory has been shown to be much influenced by column size. We evaluated the spatial variability of laboratory K-S measurements using three differ...

Temporal and spatial variability of water content in soil results from a complex interaction of different factors such as duration and frequency of rainfall, soil layering, vegetation, and topography. The objectives of this study were (i) to use a resistant median-polishing scheme to quantify the temporal variability of a depth and a horizontal loc...

The spatial variability of the Kf and n parameters of the Freundlich sorption isotherm for atrazine and their correlation with soil textural variables, cation exchange capacity and organic carbon content were studied in a stagnic podzoluvisol. Ninety-three sample points were organized on an irregular three-dimensional grid to a depth of 3.2 m. A tr...

To investigate relations between solute transport, soil properties, and experimental conditions, we summarize results from leaching experiments that we carried out in a range of soils, at different scales (column (0.3–1.0 m ID, 1.0 m length) and field plot scale), and using different leaching rates (0.5–30 cm d 1). The lateral mixing regime and lon...

While inverse parameter estimation techniques for determining key parameters affecting water flow and solute transport are becoming increasingly common in saturated and unsaturated zone studies, their application to practical problems, such as irrigation, have received relatively little attention. In this article, we used the Levenberg-Marquardt op...

In this paper, the applicability of Richards' equation for water flow and the convection-dispersion equation for solute transport is evaluated to model field-scale flow and transport under natural boundary conditions by using detailed experimental data and inverse optimization. The data consisted of depth-averaged time series of water content, pres...

In this study, the Mean Transit Time and Mixing Model Analysis methods are combined to unravel the runoff generation process of the San Francisco River basin (73.5 km2) situated on the Amazonian side of the Cordillera Real in the southernmost Andes of Ecuador. The montane basin is covered with cloud forest, sub-páramo, pasture and ferns. Nested sam...

Water movement in unsaturated soils is commonly affected by hysteresis, a phenomenon often ignored as to keep the mathematical description of water flow and solute transport simple. In this study, the importance of hysteresis was quantified at lysimeter scale on two Belgian soils, a loamy and a sandy loam soil. Undisturbed soil monoliths (79 cm dia...

This paper presents a lumped conceptual model designed for simulating the rainfallrunoff response of mountain micro-catchments with natural vegetation located in the south of Ecuador. The conceptual model is mimicking the soil hydrology and consists of a maximum of three linear reservoirs in series. A two and three reservoir model structure were te...

In this study, the Mean Transit Time and Mixing Model Analysis methods are combined to unravel the runoff generation process of the San Francisco River basin (73.5 km**2) situated on the Amazonian side of the Cordillera Real in the southernmost Andes of Ecuador. The montane basin is covered with cloud forest, sub-páramo, pasture and ferns. Nested s...

Tropical mountain regions are characterized by strong spatial climate gradients which together with the limited amount of data and knowledge of the underlying processes hinder the management of the water resources. Especially for regional-scale prediction it is important to identify the dominant factors controlling the rainfall-runoff response and...

En la actualidad, la disponibilidad de modelos digitales de elevación digital (MDEs) para representar la superficie de la tierra permite el acoplamiento de modelos hidráulicos con sistemas de información geográfica (SIG) para determinar la extensión de una inundación y los niveles del agua en la llanura de inundación. Muchos estudios de mapeo de in...

This paper provides the state-of-the-art in hydrologic modeling regarding its capability of predicting the effects of climate and land use change on the hydrological cycle. In conclusion, the research challenges are pinpointed which the community should address as to be able to observe and model regional-scale the coupled climate-water cycle in res...

Field observations of runoff generation in pristine montane cloud forests are scarce. However, this knowledge is important for a sustainable natural resources management. Here we report results of a study carried out in the San Francisco River basin (75,3 km2) located on the Amazonian side of the Cordillera Real in the southernmost Andes of Ecuador...

While remote sensing is able to provide spatially explicit datasets at regional to global scales, extensive application to date has been found only in the reporting and verification of ecosystem carbon fluxes under the Kyoto Protocol. One of the problems is that new remote sensing datasets can be used only with models or data assimilation schemes a...

This paper examines the sensitivity and uncertainty of evaporation estimates from Nasser Lake, south of Egypt using data collected at the floating station Raft, 2 km upstream of the Aswan High Dam, and 12 evaporation models. Based on their approach the evaporation models were ranked in five classes, respectively the Bowen ratio energy budget (BREB)...

Using timeseries of rainfall and streamflow of two basins in the Andean mountain range, South Ecuador, different in size (300 and 1260 Km2), a generalized lumped conceptual model (VHM), offering the possibility of using different levels of complexity with number of model parameters varying between 5 and 15, was tested. To increase the information t...

A distributed model was used to simulate the main hydrological processes in the Ourthe catchment, situated in the southern hilly part of Belgium. The study revealed important uncertainties associated with the current modelling, particularly with regard to the data of the groundwater system. These are likely to influence the global performance of th...

During the last decade several initiatives aiming at conserving and protecting the water provision of Andean ecosystems have started. However, their implementation has faced a number of limitations on the technical side, mainly due to the lack of knowledge of hydrological processes and Andean-specific developed and tested hydrological models for sc...

The recent discussion on university ranking raised quite some commotion among the Ecuadorian academic society. Because Ecuadorian universities do not produce Nobel Prize winners, public and private investment in research are limited, academicians hardly produce articles in recognized scientific journals, among other factors, are responsible that th...

This article highlights the economic and ecological value of the water resource systems of Ecuador's páramo and montane forest region and gives a description, based on a survey of recent literature, of the mechanisms controlling the rainfall–runoff process and how changes in land use alter the transformation. The review reveals that available under...

The effect of the division in number of subcatchments and the spatial distribution of areal rainfall on the prediction of streamflow was evaluated using the SWAT model and data from the Grote Nete River catchment (Flanders, Belgium). A multi-automatic calibration scheme (MACS), using the Shuffled Complex Evolution (SCE) optimization algorithm, was...

This paper presents the research performed in the wet Andean páramo ecosystem in order to study the land use change impacts on its hydrology, using small paired catchments. The research results revealed that pine plantations produce a decrease of annual water yield as a consequence of increased evapotranspiration. On the other hand, livestock grazi...

The generalised likelihood uncertainty estimation (GLUE) approach was applied to assess the performance of a distributed catchment model and to estimate prediction limits after conditioning based on observed catchment-wide streamflow. Prediction limits were derived not only for daily streamflow but also for piezometric levels and for extreme events...

Uncertainty on carbon fluxes is determined by the uncertainties of ecosystem model structure, data and model parameter uncertainties and the temporal and spatial inaccuracy of the input data retrieval. The objective of this paper is to understand the error propagation and uncertainty of evaporative fraction (EF), soil moisture content (SMC) and wat...

Time-domain reflectometry (TDR) is being used increasingly for measuring the moisture content of porous media. However, successful application for measuring water in soil has been limited to non-deformable soils, and it would be a valuable extension of the technique if it could be used for soils that shrink on drying. We have recently investigated...

This paper suggests a multi-criteria protocol for appropriately evaluating the predictions of hydrologic models during calibration and evaluation stages. The protocol includes different statistical, analytical and visual criteria such as analysis of peak and low flows, cumulative volumes, extreme value statistics, performance statistics, etc. Furth...