Flooding dynamics and nutrient retention in the middle Ebro floodplain: experimental assessment and numerical modeling

El presente trabajo destaca la simulación numérica como herramienta capaz de reproducir y predecir los principales procesos que producen y mantienen los ecosistemas de llanuras de inundación. Para ello, la dinámica del flujo, la actividad geomorfológica, la sedimentación y la captura de nutrientes de la llanura de inundación, son evaluadas experimentalmente. Seguidamente, los datos experimentales son incluidos en un modelo numérico para desarrollar una herramienta completa de simulación capaz de predecir la dinámica del flujo, la actividad geomorfológica, la sedimentación, el aporte de nutrientes del río a la llanura de inundación así como la captación de los mismos. El estudio se desarrolla en un segmento del río Ebro (NE España), representativo de su tramo medio meandriforme. El estudio emplea un modelo numérico bidimensional (2D), basado en las ecuaciones 2D de las aguas poco profundas y calculado a partir del método de los volúmenes finitos. La calibración del modelo se basa en medidas experimentales realizadas en la llanura de inundación bajo dos caudales estacionarios. La validación del modelo se llevó a cabo comparando los resultados numéricos con las medidas experimentales de nivel de agua y extensión del área inundada realizadas durante los cinco eventos de riada ocurridos en el año 2007 (79+13 % área; 0.27+0.05m nivel de agua). Las simulaciones fueron utilizadas para analizar la dinámica actual de inundación de la llanura así como su actividad geomorfológica. Como resultado, se obtuvo que el presente régimen de caudales y sobretodo la estructura morfológica de la llanura, no resulta suficiente para generar una actividad geomorfológica tal que mantenga el mosaico cambiante de hábitats característico de los ecosistemas de llanura de inundación. La nueva formulación que describe la retención de nutrientes se ha desarrollado mediante la utilización de los datos experimentales, en condiciones de flujo controladas, semi-controladas y en el propio río Ebro.González Sanchis, MDC. (2012). Flooding dynamics and nutrient retention in the middle Ebro floodplain: experimental assessment and numerical modeling [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/15242Palanci

Can a parsimonious model implemented with satellite data be used for modelling the vegetation dynamics and water cycle in water-controlled environments?

[EN] Vegetation plays a key role in catchment's water balance, particularly in semi-arid regions that are generally water-controlled ecosystems. Nowadays, many of the available dynamic vegetation models are quite complex and they have high parametrical requirements. However, in operational applications the available information is quite limited. Therefore parsimonious models together with available satellite information can be valuable tools to predict vegetation dynamics. In this work, we focus on a parsimonious model aimed to simulate vegetation and hydrological dynamics, using both field measurements and satellite information to implement it. The results suggest that the model is able to adequately reproduce the dynamics of vegetation as well as the soil moisture variations. In other words, it has been shown that a parsimonious model with simple equations can achieve good results in general terms and it is possible to assimilate satellite and field observations for the model implementation. (C) 2016 Elsevier B.V. All rights reserved.The research leading to these results has received funding from the Spanish Ministry of Economy and Competitiveness and FEDER funds, through the research projects INTEGRA (CGL2011-28776-C02) and E-HIDROMED (CGL2014-58127-C3). The MODIS data were obtained through the online Data Pool at the NASA Land Processes Distributed Active Archive Center (LP DAAC), USGS/Earth Resources Observation and Science (EROS) Center, Sioux Falls, South Dakota (https://lpdaac.usgs.gov/get_data). The meteorological data were provided by the Spanish National Weather Agency (AEMET).Ruiz Pérez, G.; González-Sanchis, MDC.; Campo García, ADD.; Francés, F. (2016). Can a parsimonious model implemented with satellite data be used for modelling the vegetation dynamics and water cycle in water-controlled environments?. Ecological Modelling. 324:45-53. https://doi.org/10.1016/j.ecolmodel.2016.01.002S455332

Hydrology-oriented forest management trade-offs. A modeling framework coupling field data, simulation results and Bayesian Networks

[EN] Hydrology-oriented forest management sets water as key factor of the forest management for adaptation due to water is the most limiting factor in the Mediterranean forest ecosystems. The aim of this study was to apply Bayesian Network modeling to assess potential indirect effects and trade-offs when hydrology-oriented forest management is applied to a real Mediterranean forest ecosystem. Water, carbon and nitrogen cycles, and forest fire risk were included in the modeling framework. Field data from experimental plots were employed to calibrate and validate the mechanistic Biome-BGCMuSo model that simulates the storage and flux of water, carbon, and nitrogen between the ecosystem and the atmosphere. Many other 50-year long scenarios with different conditions to the ones measured in the field experiment were simulated and the outcomes employed to build the Bayesian Network in a linked chain of models. Hydrology-oriented forest management was very positive insofar as more water was made available to the stand because of an interception reduction. This resource was made available to the stand, which increased the evapotranspiration and its components, the soil water content and a slightly increase of deep percolation. Conversely, Stemflow was drastically reduced. No effect was observed on Runof due to the thinning treatment. The soil organic carbon content was also increased which in turn caused a greater respiration. The long-term effect of the thinning treatment on the LAI was very positive. This was undoubtedly due to the increased vigor generated by the greater availability of water and nutrients for the stand and the reduction of competence between trees. This greater activity resulted in an increase in GPP and vegetation carbon, and therefore, we would expect a higher carbon sequestration. It is worth emphasizing that this extra amount of water and nutrients was taken up by the stand and did not entail any loss of nutrients.This study is a component of research projects: HYDROSIL (CGL2011-28776-C02-02), SILWAMED (CGL2014-58127-C3-2) and CEHYRFO-MED (CGL2017-86839-C3-2-R) funded by the Spanish Ministry of Science and Innovation and FEDER funds. The authors are grateful to the Valencia Regional Government (CMAAUV, Generalitat Valenciana), ACCIONA for their support in allowing the use of the experimental forest and for their assistance in carrying out the fieldwork.Garcia-Prats, A.; González Sanchis, MDC.; Campo García, ADD.; Lull, C. (2018). Hydrology-oriented forest management trade-offs. A modeling framework coupling field data, simulation results and Bayesian Networks. The Science of The Total Environment. 639:725-741. https://doi.org/10.1016/j.scitotenv.2018.05.134S72574163

Using post-flood surveys and geomorphologic mapping to evaluate hydrological and hydraulic models: The flash flood of the Girona River (Spain) in 2007

This paper analyzes the Girona River (Spain) flash flood, occurred on the 12th of October 2007, combining hydrological and hydraulic modeling with geomorphologic mapping and post-flood survey information. This research aims to reproduce the flood event in order to understand and decipher the flood processes and dynamics on a system of prograding alluvial fans. The hydrological model TETIS was used to characterize the shape and dimension of the October 2007 Girona River hydrograph. Subsequently, the flood event was reproduced using the free surface flow module of the model RiverFlow2D. The combination of hydrological and hydraulic models was evaluated using post-flood surveys defining maximum flooded area and flood depths. Then, simulations with different peak discharges were carried out to estimate the hydro-geomorphologic response of the Girona River floodplain, through the identification of the activation thresholds in different geomorphic elements. Results showed that the unit peak discharge of the October 2007 flood event (5 m3 s−1 km−2) was among the largest ever recorded in the area, according to the existing literature. Likewise, the hydraulic model showed a good performance in reproducing the flood event (FitA = 76%, RMSE = 0.65 m and NSE = 0.6), despite the complexity of the case, an ephemeral and ungauged river. The model simulation revealed the existence of an activation pattern of paleochannels and alluvial fans, which was altered by the presence of some anthropogenic disturbances. This multidisciplinary approach proved to be a useful strategy for understanding flash flood processes in ungauged catchments. It allowed understanding the mechanisms governing floods in alluvial fans systems and it represented a solid contribution for early warning plans and risk mitigation policies.This collaborative research was financed with the projects CGL2013-44917-R and SLWAMED CGL2014-58127-C3-2, of the Ministry of Economy and Competitiveness of the Spanish Government. Both projects were co-financed with FEDER funds. The observed rainfall and water discharge records were provided by "Sistema Automatic de Information Hidrologica (SAIH)", which belongs to the CHJ (Spain). This work was also possible due to the kind cooperation of the members of the Plataforma Ciutadana Riu Girona and several anonymous farmers interviewed during the field works. We also thank two anonymous reviewers for their useful and thought-provoking comments.Segura-Beltrán, F.; Sanchis Ibor, C.; Morales-Hernández, M.; González-Sanchis, MDC.; Bussi, G.; Ortiz, E. (2016). Using post-flood surveys and geomorphologic mapping to evaluate hydrological and hydraulic models: The flash flood of the Girona River (Spain) in 2007. Journal of Hydrology. 541(Part A):310-329. https://doi.org/10.1016/j.jhydrol.2016.04.039S310329541Part

Effects of Thinning Intensity on Forest Floor and Soil Biochemical Properties in an Aleppo Pine Plantation after 13 Years: Quantity but Also Quality Matters

[EN] In order to quantify the impacts of silvicultural treatments in semiarid forests, it is necessary to know how they affect key aboveground processes and also properties characterizing the forest floor and mineral soil compartments. The general objective of this work is to study the mid-term effects of thinning intensity on forest floor and soil properties after 13 years following the intervention. The experimental design consisted of a randomized block design with four thinning treatments (3 thinning intensity plots plus a control or unmanaged plot) and three blocks or replicates. Several determinations, such as total organic carbon, dissolved organic carbon, or basal respiration, were performed for characterizing forest floor and mineral soil by considering three random sampling points per experimental plot. Thirteen years after thinning, total organic content, the different organic carbon fractions studied, and basal respiration were higher in the forest floor of the unmanaged plot. These results, however, were contrasted to those obtained for the mineral soil, where significant differences between the treatments were only observed in basal respiration and C/N ratio, while the different organic carbon fractions were not affected by thinning intensity. Our results suggest better soil quality where biological activity is enhanced as a consequence of improved environmental conditions and also litterfall input. The latter is especially important in forests with tree leaves of low biodegradability, where new understorey species promoted by thinning can provide higher nutrient availability for the remaining trees and, therefore, better forest resilience.A.J. Molina is the beneficiary of an "APOSTD' fellowship (APOSTD/2019/111) funded by the Generalitat Valenciana. The authors received national and international funding through the following projects: SILVADAPT.NET (RED2018-102719-T funded by MCIN/AEI/10.13039/501100011033), CEHYRFO-MED (CGL2017-86839-C3-2-R funded by MCIN/AEI/10.13039/501100011033 and FEDER a way to make Europe), and RESILIENTFORESTS (LIFE17 CCA/ES/000063)Molina, AJ.; Bautista, I.; Lull, C.; Campo García, ADD.; González Sanchis, MDC.; Lidón, A. (2022). Effects of Thinning Intensity on Forest Floor and Soil Biochemical Properties in an Aleppo Pine Plantation after 13 Years: Quantity but Also Quality Matters. Forests. 13(2):1-14. https://doi.org/10.3390/f1302025511413

Explaining the hydrological behaviour of facultative phreatophytes using a multi-variable and multi-objective modelling approach

[EN] Trees in semiarid conditions survive despite water scarcity and shallow soils because they commonly have access to subsoil water resources. Currently, conventional models do not include groundwater transpiration and the results frequently underestimate the actual evapotranspiration and overestimate the net recharge. Therefore, in this work we focus on how a multi-variable calibration with a multi-objective approach may improve model robustness leading to a more realistic closure of the water balance in two models (LEACHM and TETIS) of different conceptualisation taking into account the specific characteristics of a facultative phreatophytic forest. The results suggest that the common single-variable and single-objective calibration is not able to measure all system¿s characteristics. However, the multi-variable and multi-objective calibration proved a good option to reproduce the water dynamics of a facultative phreatophytic forest and confirmed that groundwater transpiration is an important water source for them. Therefore, hydrological models should include this mechanism and both LEACHM and TETIS proved an acceptable tool to be applied in the regions covered by this species.This work was supported by the Spanish Ministry of Science and Innovation through the research projects: TETISMED (CGL2014-58127-C3-3-R), SILWAMED (CGL2014-58127-C3-2-R) and TETISCHANGE (RTI2018-093717-B-100), and by the project LIFE17 CCA/ES/000063 RESILIENTFORESTS.Puertes-Castellano, C.; Lidón, A.; Echeverria, C.; Bautista, I.; González Sanchis, MDC.; Campo García, ADD.; Francés, F. (2019). Explaining the hydrological behaviour of facultative phreatophytes using a multi-variable and multi-objective modelling approach. Journal of Hydrology. 575:395-407. https://doi.org/10.1016/j.jhydrol.2019.05.041S39540757

Effectiveness of water-oriented thinning in two semiarid forests: The redistribution of increased net rainfall into soil water, drainage and runoff

[EN] Water is the key element that modulates the provision of goods and services together with global/climate stressors affecting semiarid forests. In this sense, there is a need to improve the understanding and quantification of forest and water relationships as affected by forest management. This work addresses this issue by comparing net rainfall (Pn) redistribution into different belowground hydrological processes (BHP) in two forest types after a thinning treatment: a holm oak coppice (HU) and a post-fire Aleppo pine regeneration (CAL). The relative contribution (RI) of forest structure, antecedent soil moisture (¿st), rainfall and meteorological conditions on the BHP was assessed through boosted regression trees models. In both sites, the RI of the forest structure itself was limited (< 10%). However, ¿st, which clearly increased significantly with thinning, received an average RI of 29%. Surface and subsurface lateral flows showed values<1% of gross rainfall (Pg) in either site and were not significantly affected by thinning. On the other hand, soil moisture and drainage were affected by the thinning treatment, although with different extent depending on the site: in the drier site (CAL), the increased Pn in the thinning was mainly allocated into increased soil water content, with very limited improvement in drainage (< 10 mm/year); in contrast, in the wetter continental site of HU, drainage to deeper soil layers was the most remarkable effect of thinning (50 mm/year higher than in control), given the higher ¿st and hence the lower soil water storage available. Thinning also improved the response of BHP during drought, making these processes more elastic and less vulnerable to climatic extremes. The results presented here complement those previously reported on rainfall partitioning in these sites and all together provide a comprehensive understanding of the short-term effect (3¿4 years) of water-oriented silviculture in Quercus ilex and Pinus halepensis low-biomass semiarid forests. Questions such as the long-term effects of thinning remain open for these ecosystems.This study is a component of research projects: HYDROSIL (CGL2011-28776-C02-02), SILWAMED (CGL2014-58127-C3-2), CEHYRFO-MED (CGL2017-86839-C3-2-R) funded by the Spanish Ministry of Science and Innovation (Spain), FEDER funds (EU) and LIFE17 CCA/ES/000063 RESILIENTFORESTS. The authors are grateful to the Valencia Regional Government (CMAAUV), VAERSA, ACCIONA, the "Sierra Calderona" Natural Park and the communal authority of Serra, for their support in allowing the use of the experimental forest and for their assistance in carrying out the fieldwork. A.J. Molina is beneficiary of a "Juan de la Cierva" post-doctoral fellowship funded by the Spanish Ministry of Economy and Competitiveness.Campo García, ADD.; González Sanchis, MDC.; Molina Herrera, A.; Garcia-Prats, A.; Ceacero, CJ.; Bautista, I. (2019). Effectiveness of water-oriented thinning in two semiarid forests: The redistribution of increased net rainfall into soil water, drainage and runoff. Forest Ecology and Management. 438:163-175. https://doi.org/10.1016/j.foreco.2019.02.020S16317543

Efectos de la gestión forestal en los flujos de nutrientes asociados al ciclo hidrológico en un bosque mediterráneo de Quercus Ilex

[ES] Las interacciones entre cubierta forestal y agua son complejas ya que afectan a diferentes variables tales como reparto de los flujos de agua, cosecha de agua y calidad de la misma. El crecimiento forestal en suelos de baja fertilidad requiere que los ciclos de nutrientes dentro del ecosistema sean eficientes, especialmente en bosques mediterráneos, en los que además de los problemas de escasez de agua, el nitrógeno y el fósforo son a menudo nutrientes limitantes. El objetivo de este trabajo es analizar el impacto de la gestión hidrológico forestal sobre los flujos de nutrientes (C, N, P y K) asociados al ciclo hidrológico. Se seleccionó un bosque de encina situado en el monte público de La Hunde, Valencia (NE España). Se establecieron dos parcelas contiguas, control y tratamiento, de 1800 m2, respectivamente. En la parcela de tratamiento se reduce la densidad de 861 a 414 árboles por ha, siguiendo los requisitos del gestor forestal. Se han medido los flujos de transcolación, escorrentía cortical y se han instalado zanjas de drenaje para recoger la escorrentía superficial y subsuperficial. Durante más de un año hidrológico se han recogido muestras de agua en ambas parcelas, con una periodicidad aproximadamente quincenal, y se han medido los contenidos de C, N, P y K disueltos en el agua, tanto en forma orgánica como inorgánica, para analizar los efectos del tratamiento en el ciclo de nutrientes.Este trabajo se ha realizado en el marco del proyecto de investigación CGL2011-28776-C02-02 financiado por el Ministerio de Economía y Competitividad.Bautista, I.; Pabón Galán, CA.; Lull, C.; González-Sanchis, MDC.; Lidón, A.; Campo García, ADD. (2015). Efectos de la gestión forestal en los flujos de nutrientes asociados al ciclo hidrológico en un bosque mediterráneo de Quercus Ilex. Cuadernos de la Sociedad Española de Ciencias Forestales. (41):343-354. https://doi.org/10.31167/csef.v0i41.17400S3433544

Incorporación de criterios eco-hidrológicos en la gestión forestal: adaptación a la escasez de agua de una masa marginal de encina

[ES] El Manejo Forestal Adaptativo (MFA) en entornos semiáridos tiene como objetivo adaptar el bosque a la escasez de agua mediante una regulación artificial de la estructura y la densidad del mismo. En el presente trabajo se aplica el MFA a una masa marginal de Quercus ilex con el fin de optimizar los recursos hídricos y tratando de evitar a su vez el posible impacto negativo derivado de una pérdida excesiva de suelo y nutrientes. La masa se encuentra en la Cuenca Mediterránea, dentro del Monte Público de La Hunde, Valencia (E de España), donde dos parcelas contiguas, control y tratamiento, de 1800 m2 cada una, fueron establecidas. La orientación (NO), pendiente (30 %) y densidad (861 árboles por ha) fueron las mismas en ambas parcelas. La parcela tratamiento fue aclarada en Mayo del 2012, reduciendo la densidad de 861 a 414 árboles por ha. La parcela control no fue aclarada. Los efectos del aclareo en los ciclos hidrológico y biogeoquímico fueron caracterizados en ambas parcelas y comparados entre sí. Los resultados indicaron un efecto temprano del aclareo que optimiza el ciclo hidrológico. Se encontró un incremento significativo de la transpiración, escorrentía cortical y humedad del suelo en la parcela tratada. Por el contrario, no se observaron efectos ni en la escorrentía superficial ni en la trascolación. De la misma forma, el MFA parece no afectar significativamente al ciclo biogeoquímico del bosque, ya que no se encontraron diferencias significativas en el contenido de C, N y P en el agua de ambas parcelas. La removilización de nutrientes parece verse afectada por el resalveo. La parcela tratada muestra una menor eficiencia en el uso de los nutrientes, probablemente derivada de una mayor disponibilidad de agua. Con estos resultados, podemos afirmar que la aplicación de un adecuado MFA posibilita la optimización del ciclo hidrológico sin dañar significativamente el ciclo de los nutrientes. De la misma forma, además de la satisfacción de las necesidades hídricas y nutricionales del ecosistema, el MFA incrementa la disponibilidad de agua para el resto de la cuenca.González-Sanchis, MDC.; Campo García, ADD.; Lidón, A.; Lull, C.; Bautista, I.; García Prats, A.; Francés, F. (2015). Incorporación de criterios eco-hidrológicos en la gestión forestal: adaptación a la escasez de agua de una masa marginal de encina. Cuadernos de la Sociedad Española de Ciencias Forestales. 1(41):211-218. doi:10.31167/csef.v0i41.17389S21121814

Velocity-space sensitivity and tomography of scintillator-based fast-ion loss detectors

A simple model for the instrument function of scintillator-based fast-ion loss detectors (FILD) has been developed which accounts for the orbit trajectories in the 3D detector geometry and for the scintillator response. It allows us to produce synthetic FILD signals for a direct comparison between experiments and simulations. The model uses a weight function formalism to relate the velocity-space distribution of fast-ion losses reaching the detector pinhole to the scintillator pattern obtained experimentally, which can be understood as a distortion of the velocity-space distribution due to the finite resolution of the system. The tool allows us to recover the undistorted velocity-space distribution of the absolute flux of fast-ion losses reaching the detector pinhole from an experimental measurement using tomographic inversion methods, which can reveal additional details of the velocity-space distribution of the lost ions.Spanish Ministry of Economy and Competitiveness FIS2015-69362-P (MINECO/ FEDER,UE), RYC-2011-09152 and ENE2012-31087Marie Curie FP7 Integration Grant (No. PCIG11-GA-2012-321455)EUROfusion Consortium 63305