José Javier López

El presente trabajo analiza una metodología para obtener la velocidad y los tiempos de circulación en una cuenca hidrológica utilizando Sistemas de Información Geográfica (SIG). Los objetivos principales de la investigación son obtener los tiempos de circulación en laderas y cauces de manera semi automática para caracterizar la respuesta de la cuenca a la lluvia. La metodología se basa en la ecuación de Manning y se aplica en la cuenca de Cidacos en Navarra. Se utilizan datos de pendiente, curvatura plana, obtenidos de a partir del MDE, y el factor de rugosidad de Manning para calcular la velocidad distribuida. Se realiza un filtrado del perfil longitudinal de los cauces y se estima la anchura del cauce en cada punto. Los resultados muestran los tiempos medios de circulación en cada subcuenca en función del caudal de referencia.

In recent years, numerous studies have been carried out on changes in the temperature and precipitation regimes and in the frequency of the extreme events that are a result of climate change. While there is evidence of an increase in temperature at a global level, this globality does not seem to occur with precipitation. The Igeldo weather station (San Sebastian) has one of the longest recorded rainfall intensity series in Spain and can be considered as representative of the Cantabrian coast. This circumstance makes it the ideal place to analyse the trend of the pluviometric regime of this area, and this was precisely the objective of this study. A total of 165 series of pluviometric parameters were obtained to characterise the pluviometric regime. The Mann–Kendall and Spearman tests were applied to evaluate the trends of the different parameters, and the Pettitt test was applied to detect the existence of change points. In all the series, it was proven that there were no significant trends or change points. Significant increasing trends were only detected in the series of maximum winter precipitation. In general terms, it can be concluded that the precipitation regime in Igeldo is quite stationary in the context of climate change.

 Gully erosion is a soil degradation process widely present across the world. Permanent gully erosion has usually soil erosion rates one order of magnitude higher than hillslope water erosion in conventional agriculture, e.g. 2.1 vs 0.6 mm year-1 (Castillo and Gómez, 2016). It remains a major process of soil degradation worldwide. This work attempts to investigate recent trends of published research on gully erosion in relation to gully erosion control since 2000. A review in Web of Science (core collection, 2000-19 by title) reported 401 documents, produced mainly in the European Union (52.1%), China (22.7%), USA (16.0%) and Australia (8.7%). Approximately 17% of all these articles covered restoration or control of gully erosion as their main topic. When screened most of these 68 articles deal with specific situations and techniques with a limited number devoted to a comparative review of effectiveness of different techniques, one of the few exceptions was Liu et al. (2019a). To provide perspective, there were a similar proportion of articles devoted to the study of gully erosion processes, a and a much larger number of articles devoted to the description of gully development and erosion rates in specific situations. It is apparent that the subject of gully erosion control is not a dominant one in the scientific indexed literature. This review was complemented with an analysis in WOCAT (WOCAT, 2019), a comprehensive international databases of soil conservation technologies. It showed with 27 entries of gully erosion restoration techniques over a total of 1098 descriptions (2.5% approximately). This might be explained, partially, because most of the information on gully erosion control appears in documents outside scientific, or technical, international databases, many times in local languages. Overall, two of the major barriers frequently noted by stakeholders, particularly farmers, for effective gully erosion control, their high costs and the complexity of controlling expansion of very large gullies (e.g. Liu et al.2019b) are not major major subjects  in the international scientific literature on gullies in the last decades. It is apparent that there is the need for a more comprehensive comparative analysis of the effectiveness and cost of different strategies of gully erosion control techniques, particularly oriented to reduce the investment cost of their implementation, especially in very large gullies where compex slope instability processes might play a dominant role. This communication presents a comprehensive analysis on the available information on international scientific literature on gully erosion research to suggest key lines and strategies for future research. ReferencesCastillo, C., Gómez, J.A. 2016 A century of gully erosion research: Urgency, complexity and study approaches Earth-Science Reviews 160: 300–319Liu, X., et al. 2019a. Gully Erosion Control Practices in Northeast China: A Review. Sustainability 11: 5065, doi:10.3390/su11185065Liu, H., et al. 2019b. Using 3D scanner to study gully evolution and its hydrological analysis in the deep weathering of southern China. Catena 183. https://doi.org/10.1016/j.catena.2019.104218WOCAT. 2020. World Overview of Conservation Approaches and Technologies. https://www.wocat.net/en/

La determinación de la ley de frecuencias de precipitaciones resulta imprescindible para el diseño de diferentes infraestructuras hidráulicas así como para el análisis y determinación de zonas inundables. El objetivo de este artículo es presentar los cuantiles de las precipitaciones diarias extremas en el territorio de la Comunidad Foral de Navarra, obtenidos mediante un análisis regional de frecuencia (ARF), y su representación espacial. Se ha partido de las 142 estaciones pluviométricas manuales, localizadas en la Comunidad Foral de Navarra y en el entorno de la misma, con duración de registro superior a 20 años. El Análisis Regional de Frecuencias (ARF) se ha realizado según la metodología de Hosking y Wallis, obteniendo seis regiones homogéneas y sus funciones de distribución más adecuadas. Para la elaboración de los mapas se han aplicado dos métodos de interpolación: el de la distancia inversa ponderada; y el geoestadístico Kriging ordinario. Después del análisis comparativo se ha elegido el Kriging.

Las curvas de intensidad-duración-frecuencia (IDF) son una herramienta fundamental en ingeniería hidrológica. Se ha partido de la serie de precipitación de 88 años registrada cada diez minutos en la estación meteorológica de Igueldo (San Sebastián). Después de aplicar varios test para comprobar la homogeneidad y la no estacionariedad de la serie de precipitación, se determinaron las curvas IDF mediante un análisis de frecuencia con el programa Hydrognomon. Dichas curvas se compararon con las obtenidas a partir de la serie simulada con el modelo estocástico de Barlett-Lewis Modificado (MBL) y con las estimadas mediante la ecuación de Témez. El objetivo de este trabajo es la evaluación de estas dos últimas metodologías. Las curvas y los yetogramas generados con la expresión de Témez presentaron un buen ajuste a partir de periodos de retorno, T, mayores a 20 años. No fueron tan buenos los obtenidos a partir de la serie simulada con MBL.

Soil moisture content has always been an important parameter to control because it is a deterministic factor for site-specific irrigation, seeding, transplanting, and compaction detection. In this work, a discrete sensor that is based on a SnO₂–FP (Fabry-Pérot) cavity is presented and characterized in real soil conditions. As far as authors know, it is the first time that a microstructured optical fiber is used for real soil moisture measurements. Its performance is compared with a commercial capacitive soil moisture sensor in two different soil scenarios for two weeks. The optical sensor shows a great agreement with capacitive sensor’s response and gravimetric measurements, as well as a fast and reversible response; moreover, the interrogation technique allows for several sensors to be potentially multiplexed, which offers the possibility of local measurements instead of volumetric: it constitutes a great tool for real soil moisture monitoring.

Pamplona is a city that is crossed by the river Arga along a floodplain, which is susceptible to flooding when there are floods of certain magnitude. In this situation it is important to have a hydrological model able to simulate the flows that runs through the city centre, from the data of different gauges in the watershed, which serve to feed hydraulic models that permits to define the flooding susceptible areas associated to different levels of probability. With this end, the HEC-HMS model of river Arga’s watershed in Pamplona, has been assembled and characterised, and subsequently applied to the five most significant floods in recent years, from which the minimum required data of flow and precipitation is available. HEC-HMS is a rainfallrunoff model that consists of structuring the source watershed into sub-watersheds associated to the river network. The base flow in the observed hydrographs was estimated by the Eckhardt filter. After performing a sensitivity analysis of uncertain parameters of the model (in which it has been observed that CN is the most sensitive) the model has been applied with data from the precipitation series of the automatic stations and data from automatic plus manual stations; in the latter case the results have improved significantly, obtaining satisfactory results.