Open Access
Spatial variability of the relationships of runoff and sediment yield with weather types throughout the Mediterranean basin
(Elsevier, 2019) Peña-Angulo, Dahis; Nadal-Romero, Estela; González-Hidalgo, J. Carlos; Albaladejo, J.; Andreu, V.; Bagarello, Vincenzo; Barhi, H.; Batalla, R.J.; Bernal, S.; Bienes, Ramón; Campo, J.; Campo-Bescós, Miguel; Canatário-Duarte, Antonio; Cantón, Yolanda; Casalí Sarasíbar, Javier; Castillo, Víctor M.; Cerdà, Artemi; Cheggour, A.; Cid, Patricio; Cortesi, N.; Desir, G; Díaz-Pereira, E.; Espigares, T.; Estrany, J.; Fernández-Raga, M.; Ferreira, Carla S.S.; Ferro, Vito; Gallart, F.; Giménez Díaz, Rafael; Gimeno, E.; Gómez, Jose A.; Gómez Gutiérrez, Á.; Gómez-Macpherson, Helena; González-Pelayo, O.; Hueso-González, P.; Kairis, O.; Karatzas, G.P.; Klotz, S.; Kosmas, C.; Lana Renault, Noemí; Lasanta, T.; Latron, J.; Lázaro, Roberto; Le Bissonnais, Y.; Le Bouteiller, Caroline; Licciardello, Feliciana; López-Tarazón, J.A.; Lucía, Ana; Marín, C.; Marqués, M.J.; Martínez-Fernández, J.; Martínez-Mena, M.; Martínez-Murillo, J.F.; Mateos, Luciano; Mathys, N.; Merino-Martin, L.; Moreno de las Heras, Mariano; Moustakas, N.; Nicolau, J.M.; Novara, A.; Pampalone, Vincenzo; Raclot, D.; Rodríguez-Blanco, M. Luz; Rodrigo-Comino, J.; Romero Díaz, A.; Roose, E.; Rubio, J.L.; Ruiz-Sinoga, J.D.; Schnabel, Susanne; Senciales-González, J.M.; Simonneaux, V.; Solé-Benet, A.; Taguas, Encarnación V.; Taboada-Castro, M. Mercedes; Taboada-Castro, M.T.; Todisco, F.; Úbeda, Xavier; Varouchakis, E.A.; Vericat, D.; Wittenberg, L.; Zabaleta, Ane; Zorn, M.; Ingeniería; Ingeniaritza; Institute on Innovation and Sustainable Development in Food Chain - ISFOOD
Open Access
Hydrological effects of the sediments deposited off a hillslope affected by rill erosion: project outlines and preliminary results
(Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, 2007) Giménez Díaz, Rafael; Casalí Sarasíbar, Javier; Campo-Bescós, Miguel; Proyectos e Ingeniería Rural; Landa Ingeniaritza eta Proiektuak
The main objectives of this project are (i) to evaluate the sedimentation rate generated by rill erosion in a hillslope and the granulometric characteristics of the sediment deposited off this hillslope, and (ii) to determine the incidence of this sediment on the hydrological properties of the sedimentation area. In addition, an extra aim is to gain insight into the spatial and temporal evolution of a rill network under field condition.
Open Access
Runoff, nutrients, sediment and salt yields in an irrigated watershed in southern Navarre (Spain)
(Elsevier, 2018) Merchán Elena, Daniel; Casalí Sarasíbar, Javier; Valle de Lersundi, Jokin del; Campo-Bescós, Miguel; Giménez Díaz, Rafael; Preciado, Beatriz; Lafarga, Alberto; Landa Ingeniaritza eta Proiektuak; Institute on Innovation and Sustainable Development in Food Chain - ISFOOD; Proyectos e Ingeniería Rural
The environmental impact of irrigated agriculture on water quality was assessed in Landazuria watershed (Navarre, northeast Spain), a 479.5 ha watershed with 53% of irrigated agricultural land. In the framework of a long-term monitoring program, precipitation and discharge were measured at 10-min intervals and compound daily water samples were collected during the agricultural years (September to August) 2007–2016, and analysed for nitrate (NO3−), phosphate (PO43−), sediment and total dissolved solids (TDS) concentrations. Typical agricultural management (including crop surfaces, irrigation and fertilization rates) was obtained from inquiries to farmers. Concentration and yield of the studied variables presented a high degree of variation, both intra- and inter-annual. Median concentration for the entire study period were 185, <0.05, 31 and 2284 mg L−1 for NO3−, PO43−, sediment and TDS, respectively. NO3−-N and PO43−-P yields averaged 74 and 0.04 kg ha−1 year−1, respectively. NO3 −-N yield was higher than in other agricultural land uses in Navarre and in the order of magnitude of other irrigated areas in the Middle Ebro Valley. PO43−-P yield was in the same order of magnitude than in rainfed watersheds in Navarre but lower than in intensively grazed watersheds. Sediment yield was extremely variable, averaging 360 kg ha−1 year−1, with 44% of the total measured load recorded in a few days. It was in the lower range of those measured in Navarre for rainfed agriculture and similar to those estimated in other irrigated areas of the Middle Ebro River. TDS concentration presented a significant decreasing trend since available salts were being washed out, while TDS yield averaged 1.8 Mg ha−1 year−1. Long-term monitoring of irrigated areas is required to understand pollution processes in these agroecosystems and to adequately characterize the environmental impact of current agricultural practices on water quality, in order to implement, and adequately assess, measures to reduce agricultural pollution.
Open Access
Hydrological signatures based on event runoff coefficients in rural catchments of the Iberian Peninsula
(Wolters Kluwer, 2017) Taguas, Encarnación V.; Nadal-Romero, Estela; Ayuso, José L.; Casalí Sarasíbar, Javier; Cid, Patricio; Dafonte, Jorge; Canatário-Duarte, Antonio; Ferreira, Carla S.S.; Giménez Díaz, Rafael; Giráldez Cervera, Juan Vicente; Gómez-Macpherson, Helena; Gómez, Jose A.; González-Hidalgo, J. Carlos; Lana Renault, Noemí; Lucía, Ana; Mateos, Luciano; Pérez, Rafael; Rodríguez-Blanco, M. Luz; Schnabel, Susanne; Serrano-Muela, M. Pilar; Taboada-Castro, M. Mercedes; Zabaleta, Ane; Proyectos e Ingeniería Rural; Landa Ingeniaritza eta Proiektuak
Hydrological signatures are indices that help to describe the behavior of catchments. These indices can also be used to transfer information from gauged to ungauged catchments. In this study, different approaches were evaluated to determine volumetric runoff coefficients in 18 small/ medium experimental gauged catchments of the Iberian Peninsula and to fit runoff calculations based on precipitation data for gauged and ungauged catchments. Using data derived from 1962 events, rainfall-runoff relationships were characterized and compared in order to evaluate the various hydrological response patterns. Volumetric runoff coefficients and cumulative runoff and precipitation ratios of the events that generated runoff (Rcum) minimized the root mean square error. A linear fit for the estimation of Rcum in ungauged atchments was based on mean annual precipitation, rates of infiltration, the fraction of forest-land use, and the catchment channel length. Despite high catchment heterogeneity, Rcum resulted in a suitable parameter to evaluate hydrological variability in rural gauged and ungauged catchments. In 50% of the catchments, the precipitation accounted for less than 50% of the runoff variation. Annual precipitation, antecedent rainfall, and base flow did not have a high significance in rainfall-runoff relationships, which illustrates the heterogeneity of hydrological responses. Our results highlight the need for signature characterizations of small/medium rural catchments because they are the sources of runoff and sediment discharge into rivers, and it is more economical and efficient to take action to mitigate runoff in rural locations.
Open Access
Gully geometry: what are we measuring?
(European Geosciences Union, 2015) Casalí Sarasíbar, Javier; Giménez Díaz, Rafael; Campo-Bescós, Miguel; Proyectos e Ingeniería Rural; Landa Ingeniaritza eta Proiektuak
Much of the research on (ephemeral) gully erosion comprises the determination of the geometry of these eroded channels, especially their width and depth. This is not a simple task due to uncertainty generated by the wide range of variability in gully cross section shapes found in the field. However, in the literature, this uncertainty is not recognized so that no criteria for their measurement are indicated. The aim of this work is to make researchers aware of the ambiguity that arises when characterizing the geometry of an ephemeral gully and similar eroded channels. In addition, a measurement protocol is proposed with the ultimate goal of pooling criteria in future works. It is suggested that the geometry of a gully could be characterized through its mean equivalent width and mean equivalent depth, which, together with its length, define an “equivalent prismatic gully” (EPG). The latter would facilitate the comparison between different gullies.
Open Access
Dissolved solids and suspended sediment dynamics from five small agricultural watersheds in Navarre, Spain: a 10-year study
(Elsevier, 2019) Merchán Elena, Daniel; Luquin Oroz, Eduardo Adrián; Hernández García, Iker; Campo-Bescós, Miguel; Giménez Díaz, Rafael; Casalí Sarasíbar, Javier; Valle de Lersundi, Jokin del; Ingeniaritza; Institute on Innovation and Sustainable Development in Food Chain - ISFOOD; Ingeniería; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
Dissolved solids (DS) and suspended sediment (SS) loads are considered relevant environmental problems. They are related to a wide range of on-site and off-site impacts, such as soil erosion or salinization of water bodies. In this study, the dynamics of DS and SS concentrations and loads were assessed in five small watersheds covering representative agricultural land uses in Navarre (Spain). To this end, discharge, DS and SS concentration data were collected during ten hydrological years at each watershed outlet, and loads were computed from discharge and concentration values. DS concentration followed a seasonal pattern imposed by the availability of water, with higher concentrations recorded in low-flow periods and lower concentration in the high-flow period. SS concentration was extremely variable, with a range of 2–4 orders of magnitude in concentration for any specific discharge. Temporal variations (both intra- and inter-annual) in DS loads were explained by differences in runoff, whereas those of SS were not, being the SS loads associated mainly with specific high flow events. These temporal patterns were observed for both agricultural (this study) and non-agricultural (literature) watersheds. From the data in the Navarrese watersheds and those available in the literature, we inferred that agricultural land use, in general, tends to increase the concentration of both DS and SS. Regarding DS and SS yields, the effects of agricultural land use on DS yields are controlled by the changes in runoff rather than the (small) changes in DS concentration. In this sense, land uses changes expected to increase runoff (i.e., a shift from forested to arable or from rainfed to irrigated agriculture) would increase DS yields. On the other hand, agricultural land use tends to increase SS yields, although the effect is highly variable depending on site-specific factors, both natural (e.g., watershed shape) and anthropogenic (e.g., degree of soil conservation practices). In the Navarrese watersheds, DS yields ranged from 1.1 to 2.2 Mg ha−1 year−1 whereas SS yields ranged from 0.3 to 4.3 Mg ha−1 year−1. DS yields seem to dominate under non-agricultural conditions and in most agricultural land uses at the small watershed scale. On the other hand, SS yields dominate in watersheds with increased soil erosion as a consequence of arable land use over erosion-prone watersheds.
Open Access
Challenges and progresses in the detailed estimation of sediment export in agricultural watersheds in Navarra (Spain) after two decades of experience
(Elsevier, 2023) Barberena Ruiz, Íñigo; Luquin Oroz, Eduardo Adrián; Campo-Bescós, Miguel; Eslava, Javier; Giménez Díaz, Rafael; Casalí Sarasíbar, Javier; Ingeniería; Ingeniaritza; Institute on Innovation and Sustainable Development in Food Chain - ISFOOD
Soil erosion is a very serious environmental problem worldwide, with agriculture considered the main source of sediment in inland waters. In order to determine the extent and importance of soil erosion in the Spanish region of Navarra, in 1995 the Government of Navarra established the Network of Experimental Agricultural Watersheds (NEAWGN), which consists of five small watersheds representative of local conditions. In each watershed, key hydrometeorological variables, including turbidity, were recorded every 10 min, and daily samples were taken to determine suspended sediment concentration. In 2006, the frequency of suspended sediment sampling was increased during hydrologically relevant events. The main objective of this study is to explore the possibility of obtaining long and accurate time series of suspended sediment concentration in the NEAWGN. To this end, simple linear regressions between sediment concentration and turbidity are proposed. In addition, supervised learning models incorporating a larger number of predictive variables are used for the same purpose. A series of indicators are proposed to objectively characterize the intensity and timing of sampling. It was not possible to obtain a satisfactory model for estimating the concentration of suspended sediment. This would be mainly due to the large temporal variability found of the physical and mineralogical characteristics of the sediment, which would be affecting the turbidity value, independently of the sediment concentration, per se. This fact would be particularly important in small river watersheds such as those of this study, and especially if their physical conditions are spatially and temporally radically disturbed by agricultural tillage and by a constant modification of the vegetation cover, as is the case in cereal basins. Our findings suggest that better results could be obtained by including in the analysis variables such as soil texture and exported sediment texture, rainfall erosivity, and the state of vegetation cover and riparian vegetation.
Open Access
Evaluación de la producción de sedimentos y calidad de las aguas en cuencas agrarias de Navarra
(Universidad de La Rioja, 2012) Giménez Díaz, Rafael; Casalí Sarasíbar, Javier; Díez Beregaña, Javier; Proyectos e Ingeniería Rural; Landa Ingeniaritza eta Proiektuak; Gobierno de Navarra / Nafarroako Gobernua
The Government of Navarre (Spain) established a series of experimental watersheds on different sites of its territory in order to assess the impact of the agricultural activities on the environment. Hydrological/meteorological and water quality data are continuously monitored. In this paper, data recorded –precipitation, runoff, sediment, nitrate and phosphate– in two grain-sown watersheds (La Tejería and Latxaga) and in a third one (Oskotz) covered with forest and pasture (cattle-breeding) with a sub-watershed almost entirely under forest, are analyzed; the information covers a period of ca. 15 years. The inter/intra annual variability of the involved processes are studied as well as their impact on the water quality and on the ecosystem. The majority of the sediments yielded in the watersheds are registered during winter, though most of the erosive rainfalls occurred in summer. This is because of the easy-prone runoff that prevailed during winter due to the (much) higher water content of the soils in this period. The grain-sown watersheds –roughly similar at first view– present however important differences regarding sediment yield: 1800 kg/ha year at La Tejería and only 450 kg/ha year at Latxaga. This could be mainly due to differences in morphology, topography, and amount of stream channel vegetation between both sites. At Oskotz this figures are as a whole lower than those registered in the cultivated watersheds but eventually larger than those at Latxaga; this depending on the forest management (logging). Water quality is seriously affected at La Tejería with nitrate concentration constantly over critical threshold. By contrast, nitrate values are much lower in Latxaga watershed. However, phosphate concentrations were similar in both grain-sown watersheds corresponding to water with a significant risk of eutrophication. The cattle-breeding activity at Oskotz generated unexpected levels of phosphate much higher than those registered in the cultivated wathersheds.
Open Access
Evaluation of 2D models for the prediction of surface depression storage using realistic reference values
(Wiley, 2016) Giménez Díaz, Rafael; Mezkiritz Barberena, Irantzu; Campo-Bescós, Miguel; Álvarez-Mozos, Jesús; González de Audícana Amenábar, María; Martínez de Aguirre Escobar, Alejandro; Casalí Sarasíbar, Javier; Proyectos e Ingeniería Rural; Landa Ingeniaritza eta Proiektuak
Depression storage (DS) is the maximum storage of precipitation and runoff in the soil surface at a given slope. The DS is determined by soil roughness that in agricultural soils is largely affected by tillage. The direct measurement of DS is not straightforward because of the natural permeability of the soil. Therefore, DS has generally been estimated from 2D/3D empirical relationships and numerical algorithms based on roughness indexes and height measurements of the soil surface, respectively. The objective of this work was to evaluate the performance of some 2D models for DS, using direct and reliable measurements of DS in an agricultural soil as reference values. The study was carried out in experimental microplots where DS was measured in six situations resulting from the combination of three types of tillage carried out parallel and perpendicular to the main slope. Those data were used as reference to evaluate four empirical models and a numerical method. Longitudinal altitudinal profiles of the relief were obtained by a laser profilometer. Infiltration measurements were carried out before and after tillage. The DS was largely affected by tillage and its direction. Highest values of DS are found on rougher surfaces mainly when macroforms cut off the dominant slope. The empirical models had a limited performance while the numerical method was the most effective, even so, with an important variability. In addition, a correct hydrological management should take into account that each type of soil tillage affects infiltration rate differently.
Open Access
Progress in gully erosion research: IV International Symposium on Gully Erosion
(Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, 2007) Casalí Sarasíbar, Javier; Giménez Díaz, Rafael; Proyectos e Ingeniería Rural; Landa Ingeniaritza eta Proiektuak
The classic forms of water erosion of the soil comprise sheet, rill, and gully erosion. According to the concept most generalized, in sheet erosion, thin layers of material are uniformly removed from the soil surface due to the action of an overland flow, in a homogeneous manner, over the area affected. This results in a normally very gradual and inappreciable loss of soil. However, in rill and gully erosion, the soil loss is caused by the intense action of a concentrated flow, which thus triggers the formation of small or large channels, i.e. rills or gullies, although the mechanisms implicated in either form of concentrated flow erosion are not identical. One of the main differences probably lies in the (much) greater interrelation between the roughness of the channel bed and the hydraulics of the water flow observed in a eroded rill, with respect to what occurs in a typical gully. So, the latter, as a physical process, deserves a special and specific study. Gully erosion, of world-wide importance, is catalogued by some of the principal centres devoted to soil resource conservation as being the foremost problem to be solved. As it is one of the most serious forms of water erosion, this phenomenon is capable of generating major soil losses even though it covers limited land surfaces. Additionally, the damage caused by this type of erosion frequently spreads beyond the area directly affected, i.e. through the siltation of lakes and reservoirs due to the large amounts of sediments it originates. Nevertheless, gully erosion has not received the attention that it warrants from the scientific community. For instance, a rapid search through any important virtual library shows that only less than 10% of soil erosion studies published up to now in international scientific journals deal directly and specifically with gully erosion. More research and surveys are required in order to obtain a better understanding of the physical mechanisms involved in this type of erosion, with the ultimate aim of developing accurate prediction algorithms and efficient control and damage prevention systems. In fact, there are so many unanswered questions on this important environment topic that scientists all over the world have been holding periodic meetings, in which the latest knowledge and advances in the study of gully erosion have been expounded. The first of these meetings was held in Leuven (Belgium) in 2000, the second in Sicuani (China) in 2002 and the third in Oxford, Mississippi (U.S.A.) in 2004. On that last occasion, the participants proposed that Pamplona (Spain) should be the seat of the following meeting, to be held in September 2007. This book contains the abstracts both from the key speeches and from the contributions presented in the IV International Symposium on Gully Erosion held in Pamplona, in September, 2007.