Browsing by Author "Wyseure, Guido"

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Climate changes of hydrometeorological and hydrological extremes in the Paute basin, Ecuadorean Andes
(2014) Mora Serrano, Diego Esteban; Campozano Parra, Lenin Vladimir; Cisneros Espinoza, Felipe Eduardo; Wyseure, Guido; Willems, Patrick
Investigation was made on the climate change signal for hydrometeorological and hydrological variables along the Paute River basin, in the southern Ecuador Andes. An adjusted quantile perturbation approach was used for climate downscaling, and the impact of climate change on runoff was studied for two nested catchments within the basin. The analysis was done making use of long daily series of seven representative rainfall and temperature sites along the study area and considering climate change signals of global and regional climate models for IPCC SRES scenarios A1B, A2 and B1. The determination of runoff was carried out using a lumped conceptual rainfall–runoff model. The study found that the range of changes in temperature is homogeneous for almost the entire region with an average annual increase of approximately +2.0 °C. However, the warmest periods of the year show lower changes than the colder periods. For rainfall, downscaled results project increases in the mean annual rainfall depth and the extreme daily rainfall intensities along the basin for all sites and all scenarios. Higher changes in extreme rainfall intensities are for the wetter region. These lead to changes in catchment runoff flows, with increasing high peak flows and decreasing low peak flows. The changes in high peak flows are related to the changes in rainfall extremes, whereas the decreases in the low peak flows are due to the increase in temperature and potential evapotranspiration together with the reduction in the number of wet days.
Comment on "Human impacts on headwater fluvial systems in the northern and central Andes" (Carol P. Harden, Geomorfología 79, 249 263)
(2008-04-01) Célleri, Rolando; Buytaert, Wouter; De Bièvre, Bert; Cisneros, Felipe; Wyseure, Guido; Deckers, Seppe
The high altitude grasslands of the tropical Andes, known as páramo, are a very fragile and unique ecosystem. Despite increasing human activities, many of its geomorphological and hydrological processes are still very poorly understood. We therefore welcome the paper of Harden [Harden, C.P., 2006. Human impacts on headwater fluvial systems in the northern and central Andes. Geomorphology 79, 249-263.] about "Human impacts on headwater fluvial systems in the northern and central Andes" as a valuable contribution to a better understanding of this complex ecosystem. However, in view of the available literature, we would like to complement the interpretation of the presented results and discuss some of the claims made in the paper.
Gap filling based on a quantile perturbation factor technique
(Curran Associates, 2014) Mora Serrano, Diego Esteban; Willems, Patrick; Wyseure, Guido
The presence of gaps in hydro-meteorological series is a common problem at the moment of analyzing data series. That is the case of the Ecuadorian hydrological data series, presenting eventual gaps of short term duration. The Paute River Basin, located in the Southern Ecuadorian Andes, is one of the most monitored basins in Ecuador, with 25 rainfall observed sites during the period of 1963 till 1990. However, its data base suffers of about 20% of missing data. For this research, two techniques were evaluated comparing their efficiency in the filling of missing gaps. The first one is based on multiple linear regressions, which applies a logarithmic transformation to the data and then converts the data to normalized standard variables. The second one is a new proposed technique based on quantile perturbation approach after a classical prior gap filling. It is used to shelter estimations for high and low intensities based on: i. Identification of the station with the highest monthly correlation ii. Selection and ranking of the stations for which the correlation is significant, tested by the t-test, iii. Gap filling based on the stations with the highest significant correlation, and iv. the application of a correction factor to the filled value. For the evaluation, 3 un-interrupted daily rainfall data series were selected. Data series were deleted in a random way, simulating the 20% of missing data. The two filling techniques were applied separately. Finally, data series were evaluated by the different statistic criteria. Results indicate that the proposed technique performs an efficient filling of missing gaps. It supports the definition of gaps corresponding to high or low events and avoids, in a certain range, the averaging of the series. However, it might lead to double counting of high/low extremes events.
Human impact on the hydrology of the Andean páramos
(2006) Buytaert, Wouter; Célleri, Rolando; De Bièvre, Bert; Cisneros, Felipe; Wyseure, Guido; Deckers, Jozef; Hofstede, Robert
This paper analyses the problems involved in the conservation and management of the hydrological system of the South American páramo. The páramo consists of a collection of neotropical alpine grassland ecosystems covering the upper region of the northern Andes. They play a key role in the hydrology of the continent. Many of the largest tributaries of the Amazon basin have their headwaters in the páramo. It is also the major water source for the Andean highlands and a vast area ofarid and semi-arid lowlands, where páramo water is used for domestic, agricultural and industrial consumption, and the generation of hydropower. Recently, the páramo is increasingly used for intensive cattle grazing, cultivation, and pine planting, among others. These activities, as well as global phenomena such as climate change, severely alter the hydrological regime. A review on the state of knowledge of its hydrology is given in a first part. In a second part, the impact of human activities and climate change on the hydrology of the páramo is discussed.
Impacts of climate change on catchment runoff for the Paute river basin in the southern Ecuadorian Andes (invloed van klimaatsverandering op de neerslagafstroming van het Paute-rivierbekken in de Zuid-Ecuadoriaanse Andes)
(Katholieke Universiteit Leuven, 2013-10-23) Mora Serrano, Diego Esteban; Willems, Patrick; Wyseure, Guido
The objective of this research is the evaluation of climate change scena rios and the impact it will have in water quantity and quality parameter s for future analysis actions of mitigation and adaptation. The evaluation will be performed at different spatial and temporal resol ution with the development of a calibrated and validated Lumped Co nceptual Hydrologic Model The research consist in three workpackages: 1. Model Development: Consistencies between a detailed local scale model and a regional scale conceptual model. < /UL> Research activities will consist in conducting the assessment of a regio nal scale model VHM (Generalized lumped conceptual and parsimonious mode l structure-identification and calibration, according to the Dutch abbre viation), reported as a draft publication of Dr. Prf. Patrick Willems, c oncerned in the analysis of hydrological processes and water quality imp rovement of the model< //UL> a) Improvement and advance of the existing model of Dr. Rolando Celleri, for the basin upstream of River Tomebamba in Monay 1260 km2 (meso-scale riverbasin) b) Same activity at subbasin scale level: Matadero basin 300 km2 and Llaviuco Basin 52 km2), and analysis of regio nal differences (in catchment properties and model parameters) 2 Scenario Development:< /UL> Analysis of trends and oscillations in climatic and hydrologic series< //UL> a) Analysis of rainfall and climatic series of long term weather station s: Analysis of rainfall series; Analysis of temperature and/or ETo series; Analysis of flow series of long term f low gauging stations. < /UL> The downscaling of the IPCC-SRES for the construction of the future clim ate use will be made of the downscaling of regional climate models, for which assistance will be searched for by INAMHI (Instituto Nacional de M eteorología en Hidrología, Quito-Guayaquil, Ecuador), also experience of the Laboratory of Hydraulics, Katholieque Universiteit Leuven)< //UL> a) Assessment and selection of available GCM simulations for rainfall, t emperature, ETo, and other relevant variables b) Development, implementation and evaluation of methodology to do wnscale GCM simulation results c) Consistency check of climate change scenarios with trends ident ified in Activity 2 for rainfall, temperature and ETo series 3 Climate change impact on hydrology: < /UL> Hydrologic impact analysis of climate change in the Tomebamba< //UL> a) Simulation of climate change scen arios developed in Activity 3 in the regional hydrologic models develope d in Activity 1 b) Statistical evaluation of climate chang e impact results c) Consistency check of climate change sce narios with trends identified in Activity 2 for rainfall, temperat ure and ETo series It is believed that the proposed research in the assessment of local and regional models of water quantity and quality and the effects of climat e change in the southern Ecuador Andes region which is of scientific but also relevant for the socio-economy aspects for the region.
Integrating hydraulic, physicochemical and ecological models to assess the effectiveness of water quality management strategies for the river Cuenca in Ecuador
(2013-04-10) Holguin Gonzalez, Javier E.; Boets, Pieter; Alvarado, Andrés; Cisneros, Felipe; Carrasco, María C.; Wyseure, Guido; Nopens, Ingmar; Goethals, Peter L. M.
During the past decades, the development and use of ecological models to predict the presence or absence of macroinvertebrates as water quality indicators for decision support in river management has gained a lot of interest. However, these models rarely integrate hydromorphological, physicochemical, and biological components in the submodels. We developed a generic framework for decision support in water management that can be applied to any river basin based on an integrated modelling approach. This approach integrates a mechanistic hydraulic and physicochemical water quality model with aquatic ecological models. Two types of ecological models were developed, habitat suitability models to predict the occurrence of macroinvertebrates and ecological assessment models to predict a biotic index score. Our main purpose was to assess the effectiveness of different wastewater treatment/disposal strategies considering receiving water's ecological aspects and to determine water quality requirements. This paper presents the testing and validation of this integrated framework on a case study of a mountain river (River Cuenca) in the Andes of Ecuador. Three wastewater management scenarios were tested. The different scenarios indicated that the foreseen investments in sanitation infrastructure will lead to modest improvements of the ecological water quality. This improvement (i.e. increase of the biotic index) was only identified in 6 of the 21 monitoring stations considered in the River Cuenca and its tributaries. Therefore, it is necessary to control the impact of the industrial wastewaters discharges and the diffuse pollution at the upper catchment of the tributaries to achieve a good ecological status. With these results, we proved that integrated models, like the one presented here, have an added value for decision support in water management by coupling ecological water quality to a set of hydraulic and chemical water quality measures based on a water quality model. In order to improve these models, it is necessary to change the river monitoring strategy towards collection of data which include simultaneous measurements of physicochemical, hydromorphological and biological data.
Modelamiento de operación de embalses para el proyecto integral de riego en la cuenca del río Macul
(Universidad de Cuenca, 2014) Tinoco, Vicente; Willems, Patrick; Wyseure, Guido; Cisneros, Felipe; Universidad de Cuenca; Dirección de Investigación de la Universidad de Cuenca; DIUC
An irrigation project is planned in the Macul Basin Ecuador for developing the agriculture as the main income in the region. The proposed water system comprises three large reservoirs damming the rivers Macul and Maculillo. The river basin planning and operation was investigated by modelling alternative reservoir operation strategies aiming at a sustainable balance between irrigation and river ecology by integrated reservoir/river management. The model simulates the integrated water system for long term periods of data, covering also several historical extreme events. Results indicate that the planned irrigation volumes are higher than the available water for a sustainable irrigation. Two lines of action are suggested for reaching the target irrigation demands: one is to design a deficit irrigation schedule, and the second implies modification in the reservoir’s spillway height.
Multi-scale monitoring and modelling for the analysis of the hydrologic response of southern Ecuadorian Andean páramos
(Katholieke Universiteit Leuven, 2017-09-24) Iñiguez Moran, Vicente Mauricio; Bauwens, Willy; Wyseure, Guido
The present research is focused on an “alpine” Neotropical grassland ecosystem, situated between ca. 3500 and 4500 m a.s.l. –locally known as “páramo”– which covers the Andean mountains. Below the páramo, the study area hosts other types of high-altitude Andean ecosystems, such as: tropical montane cloud forest and grasslands. The study area is located in the south-west highlands of the Paute River basin that drains to the Amazon River. These highlands form part of the western Cordillera in the Ecuadorian Andes with a maximum altitude of 4420 m a.s.l. The study area comprises a mountain range from 2647 to 3882 m a.s.l. Two neighbouring basins have been selected from this region: Portete (24.4 km2) and Cumbe (44.0 km2). In addition, a small headwater catchment located in the highlands of the Rircary River basin, a neighbour catchment to Portete (Jordanita, 2.70 km2), is also part of the research area. The overall objective of the research is to show how a multi-scale monitoring set-up for experimental research catchments can be implemented and used to establish the foundations of a hydrological observatory in the southern Ecuadorian Andean region. In addition, the research presents a thoughtful approach to catchment modelling and the interaction between modelling and experimental hydrology. A detailed characterization of the weather of three high-altitude Andean ecosystems (i.e. páramo, tropical montane cloud forest and grasslands) was carried out. As a result, the air temperature patterns recorded in both ecosystems –forest and páramo– were the same. Therefore, it is possible to conclude that the land cover has no influence over the lapse rate air temperature as compared with the effect of the altitude. The altitudinal range analysed was of ca. 1000 m. In addition, the water balance at catchment scale allowed to conclude that the land cover has no significant effect on the Ea as compared with the amount of rainfall that actually receives each ecosystem (páramo or tropical montane cloud forest). Hydrological modelling with TOPMODEL By comparing the results of the implementation of TOPMODEL (a TOPography based hydrological MODEL) for the páramo catchments, it was found that the effective parameters, which reflect the characteristics of the catchments, increase in magnitude as a function of the size of the catchment (which increased from 0.21 km2 up to 4.39 km2). Reliable predictions of TOPMODEL were confirmed by field measurements but, the implicit assumption used to calculate the topographic index (i.e. the upslope contributing area “” should be constant for any point) is not fully valid. This has to be reviewed in future applications of TOPMODEL for páramo, which is suffering more frequent drought events. In this context, the drought analysis allowed to conclude that at the plot scale, the differences between the recovery of the soils were relatively large. The measured water content in páramo soils showed a quicker recovery compared to the mineral soils located below the páramo. At the catchment scale, though, the differences in the speed of recovery derived from the soil water storage simulated by the Probability Distributed Moisture model and the drought analysis was not as pronounced. Only for the prolonged drought event of 2009-2010 were the differences larger. The difference between the precipitation and the potential evapotranspiration has been shown to have more impact on the regional difference in hydrologic behaviour than the difference between the water storage capacities of the soils. Policy makers and researchers will be able to compare these baseline results with future hydrological and soil monitoring data, to track changes in the páramo ecosystem.
Regional variability of volcanic ash soils in south Ecuador: the relation with parent material, climate and land use
(2007) Buytaert, Wouter; Deckers, Jozef; Wyseure, Guido
The high Andes region of south Ecuador is characterised by intense land use changes. These changes affect particularly the páramo, which is a collection of high altitudinal grassland ecosystems. In this region, the interaction between airborne volcanic ashes and the cold and wet climate results in very typical soils, with an elevated organic C contents. The physical soil properties are closely related to the high and reliable base flow in rivers descending from the páramo, which makes them important for the socio-economic development of the region. In this study, we analyse the regional variability of the soils in the south Ecuadorian rio Paute basin. In a first part of the study, data from soil profiles along north–south transects are used to determine the soil properties, and to relate the spatial variability of these properties to the major trends in parent material, volcanic ash deposits and climate. The profiles are Histic Andosols and Dystric Histosols devoid of allophane, with very high amounts of organic matter. Significant differences between the western and central mountain range are observed, as well as a general decrease in Andic properties from north to south, coinciding with the decrease in volcanic influence. Finally, the impact of human activities on the soil properties is assessed in a case study in the Machangara valley. Data from 5 profiles, located in an area with natural grass vegetation and a low degree of human impact are compared with 4 profiles in a heavily disturbed, intensively drained cultivated area. Despite the intensity of the land use, very few significant differences are found.
Seasonal rainfall patterns classification, relationship to ENSO and rainfall trends in Ecuador
(2018) Tobar Solano, Vladimiro Alexis; Wyseure, Guido
Water is one of Ecuador's most important natural resources, whose management should rely on good information and adequate models for the water balance. Although there are many studies focusing on rainfall and temperatures, most of them are localized for specific projects or study basins. The convergence of factors like its location in the Intertropical Convergence Zone, the Amazon River basin, the complex topography of the Andes, and being next to the Pacific Ocean impacted by the El Niño Southern Oscillation, modelling climate in Ecuador is a challenging task. The aim of this research was to classify seasonal rainfall patterns, using robust procedures to deal with missing values and outliers. The selected database contained 319 stations with monthly rainfall from 1982 to 2011. A hierarchical clustering technique applied to the proportion of monthly rainfall percentiles allowed identifying four clusters that, when compared to a digital elevation model, resulted geographically related to Sierra, Coast, Amazon and Coast Orographic Sierra (COS). Coast shows strong seasonality with the dry season from June to November, while COS presents a similar pattern with moderate seasonality, the Amazon exhibits mild to no seasonality and the Sierra with a moderate seasonality. Interestingly, the Amazon seasonality enters rather deep into the Sierra through large river valleys. Cumulative differential plots of the standardized deleted deviations of monthly rainfall aided detecting cluster dependent El Niño effects in rainfall for Coast and COS. Correlations of rainfall versus SST at El Niño regions were also cluster dependent, with low to no significant correlations for Amazon, higher correlations for Coast and COS and moderate correlations for Sierra. Monthly rainfall trends assessed by the non-parametric method of Sen's slopes, showed overall decreasing trends for September and October rainfall and increasing from February to April, thus suggesting a strengthening of seasonality. © 2017 Royal Meteorological Society
Spatial and temporal rainfall variability in mountainous areas: A case study from the south Ecuadorian Andes
(2006-10-15) Buytaert, Wouter; Célleri, Rolando; Willems, Patrick; Bievre, Bert De; Wyseure, Guido
Particularly in mountain environments, rainfall can be extremely variable in space and time. For many hydrological applications such as modelling, extrapolation of point rainfall measurements is necessary. Decisions about the techniques used for extrapolation, as well as the adequacy of the conclusions drawn from the final results, depend heavily on the magnitude and the nature of the uncertainty involved. In this paper, we examine rainfall data from 14 rain gauges in the western mountain range of the Ecuadorian Andes. The rain gauges are located in the western part of the rio Paute basin. This area, between 3500 and 4100 m asl, consists of mountainous grasslands, locally called páramo, and acts as major water source for the inter-Andean valley. Spatial and temporal rainfall patterns were studied. A clear intraday pattern can be distinguished. Seasonal variation, on the other hand, is low, with a difference of about 100 mm between the dryest and the wettest month on an average of about 100 mm month−1, and only 20% dry days throughout the year. Rain gauges at a mutual distance of less than 4000 m are strongly correlated, with a Pearson correlation coefficient higher than 0.8. However, even within this perimeter, spatial variability in average rainfall is very high. Significant correlations were found between average daily rainfall and geographical location, as well as the topographical parameters slope, aspect, topography. Spatial interpolation with thiessen gives good results. Kriging gives better results than thiessen, and the accuracy of both methods improves when external trends are incorporated.
Statistical analysis on the performance of global and regional climate models for the Paute river basin in the south-ecuadorian andes
(TuTech Innovation, 2012) Mora Serrano, Diego Esteban; Tie, Liu; Cisneros Espinoza, Felipe Eduardo ; Wyseure, Guido; Willems, Patrick
Climate change impact in the Andes regions is expected to have a large influence on water resources as in many other regions of the world. However, a major problem for climate change impact studies on the region is the high spatial variability of rainfall and temperature, which is not well represented in climate models. Different Global Climate Model (GCM) simulations available from the IPCC AR4 as well as simulations from the Regional Climate Model (RCM) PRECIS have been analyzed for the Paute river basin in the South-Ecuadorian Andes. This river basin has a wide range of topographical elevations and covers different hydrological regimes, represented in this study by six weather stations. The control simulation results from the climate models were statistically checked for inconsistencies by quantifying the differences between control period and historical time series data of rainfall and temperature. This was done for annual, monthly and daily values regarding the return period. In addition statistics criteria of relative mean squared error, bias and correlation were also computed. Results show that no model performed well for all the criteria, but some models were generally better than others. The set of best performing models, however, differed from station to station. Surprisingly, several GCMs showed better results than the RCMs for rainfall. The results reveal that a strong increase in the climate model spatial resolution does not necessarily result in more accurate description of local climate properties. Therefore, statistical downscaling techniques are crucial in climate change impact studies for these regions.
Statistical spatial and temporal analysis of historical rainfall and evapotranspiration behavior for Ecuador
(Katholieke Universiteit Leuven, 2019-11-26) Tobar Solano, Vladimiro Alexis; Wyseure, Guido; Willems, Patrick
Statistical analysis of temporal and spatial data: example of rainfall, temperature and evapotranspiration in Ecuador Many studies in Ecuador had taken the endeavor of climate characterization, mainly referred to rainfall and temperatures, and some others to estimating evapotranspiration based on data availability. Such studies have only had local application and had focused on the rainfall gauging stations; fewer stations that have temperature records and even lesser that have information of the various parameters required for the widely used Penman - Monteith equation for estimating evapotranspiration. The main challenge in modeling climate in Ecuador comes from its location in the Intertropical convergence zone, the marine currents in the Pacific, the Amazon basin and the Andes. Therefore, characterization of climate is a first step in order to understand its spatial and temporal variability, and from here to undertake the task of generalizing meteorological elements to the whole country. There needs to be a compromise between data availability that sets boundaries to what can be done and the research objectives of spatial climate patterns. Regarding information, monthly data is available referred to rainfall, for a lesser number of stations temperature is also available; and other elements like wind speed, relative humidity, dew point, pressure, and solar radiation, are only available for a selected set of stations, making it difficult to count on them. GIS spatial data features are also available, like the SRTM DEM 90m, from which morphological characteristics can be derived. First step towards analysis is data validation. Many unforeseen circumstances affect meteorological elements measure and record until final presentation of raw data, and one of the most widely used technique to detect systematic errors is the double mass curve analysis, which will be applied mainly to rainfall information, time series plots may also help identifying errors in other elements like temperatures. Spatial distribution of rainfall will be addressed by means of distribution and seasonal rainfall patterns that will enable categorizing climatic regions. Correlation analysis will be used to estimate missing values and also to estimate ungauged parameters. The main aim is to contribute to a better understanding of climate in Ecuador; by means of models including Andes mountain range and Amazon and coastal regions, for the estimation of various elements like rainfall, temperature and evapotranspiration. Spatial regions with different behavior in rainfall, temperatures and evapotranspiration will be identified. Last but not least, since Ecuador is heavily affected by the extreme anomalies of ENSO, whose presence causes long term heavy rainfalls, and floods, climate characterization should consider its influence.
The effect of land-use changes on the hydrological behaviour of histic andosols in south Ecuador
(2005-12) Buytaert, Wouter; Wyseure, Guido; Bievre, Bert De; Deckers, Jozef
The south Ecuadorian Andean mountain belt between 3500 and 4500 m altitude is covered by a highly endemic and fragile ecosystem called paramo. The Histic Andosols covering this regi ´ on have highly developed hydric properties and exert a key function in the hydrological regulation of the paramo ecosystem. Unlike most Andosols, their extreme ´water retention capacity is not due to the presence of typical minerals such as allophane or imogolite. Although these minerals are virtually absent, the large organic carbon content, due to organometallic complexation, gives rise to similar properties. The water content at 1500 kPa can exceed 2000 g kg 1, and the high hydraulic conductivity at saturation (about 15 mm h 1) drops sharply when low suction is applied. The three methods applied, i.e. the inverted auger hole, the tension infiltrometer and the constant-head permeameter method, give very similar results. The paramo ´is characterized by a slow hydrological response and a good water regulation, caused by the combination of a high water storage capacity and high conductivity. The wide pore size distribution of the organometallic complexes results in a water retention curve that differs significantly from the classic Mualem–Van Genuchten description, but can better be described with a simple linear or semilogarithmic model. The soils investigated are very prone to irreversible structural changes caused by land-use changes. The conversion of natural land for cultivation has a large impact on the hydrological function of the region. The water storage capacity increases by 5 to 30%, and the hydraulic conductivity is 31% higher in cultivated catchments. These changes are related to a larger peak flow, a smaller base flow and generally a smaller discharge buffering capacity, despite the higher storage capacity. Copyright  2005 John Wiley & Sons, Ltd
The use of the linear reservoir concept to quantify the impact of changes in land use on the hydrology of catchments in the Andes
(2004) Buytaert, Wouter; Wyseure, Guido; Deckers, Jozef; De Bièvre, Bert
The high Andes region of South Ecuador (The Paramo) is characterized by a cold and wet climate. Most soils of the Páramo region are Andosols and Histosols, with a very high water retention capacity that is affected irreversibly by drying. This key property of Páramo soils buffers catchment outflow, resulting in an almost uniform outflow pattern which, notwithsyanding the variability in rainfall, can be very variable in space and time. These soils serve as the most important reservoir of drinking and irrigation water for the densely populated inter-Andean depression region. The Páramo has long served only as an extensive grazing area but recent population pressure and land scarcity have increased cultivation. Two small Páramo catchments (about 2 km2) were monitored intensively for precipitation and discharge for over a year to assess the effect of such land-use changes on the hydrological properties. One catchment is in an undisturbed area and grazed intensively while in the other, local farmers started intensive drainage for cultivation of potatoes about five years ago. The linear reservoir concept has been used to assess the overall retention capacity of the catchment in terms of both peak response and base flow. In this model, every catchment is considered as a series if independent parallel reservoirs, each characterized by mean residence times (T). In every catchment, three major mean residence time can be distinguished. In the undisturbed catchment, an immediate response. characterized by a T of 5.4 hours, is followed by a slower response with a T of 44.3h. The base flow has mean T value of 360 h. The response of the cultivated catchment is similar with T values of 3.6 h., 27.2 h and 175 h, respectively. As a result, in the disturbed catchment, water release is about 40% faster than in the undisturbed catchment, so that the base flow falls rapidly to lower levels. The linear reservoir model is a simple way of quantifying the impact of land use changes on the water regulation capacity of Páramo catchments.