Person:
Giménez Díaz, Rafael

person.page.identifierURI

https://academica-e.unavarra.es/handle/2454/49147

Last Name

Giménez Díaz

First Name

Rafael

person.page.departamento

Ingeniería

person.page.instituteName

IS-FOOD. Research Institute on Innovation & Sustainable Development in Food Chain

ORCID

0000-0003-3210-0578

person.page.upna

6698

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Now showing 1 - 10 of 16

Open Access
Relationship of weather types on the seasonal and spatial variability of rainfall, runoff, and sediment yield in the western Mediterranean basin
(MDPI, 2020) Peña Angulo, D.; Nadal-Romero, Estela; Campo-Bescós, Miguel; Casalí Sarasíbar, Javier; Giménez Díaz, Rafael; Ingeniaritza; Institute on Innovation and Sustainable Development in Food Chain - ISFOOD; Ingeniería
Rainfall is the key factor to understand soil erosion processes, mechanisms, and rates. Most research was conducted to determine rainfall characteristics and their relationship with soil erosion (erosivity) but there is little information about how atmospheric patterns control soil losses, and this is important to enable sustainable environmental planning and risk prevention. We investigated the temporal and spatial variability of the relationships of rainfall, runoff, and sediment yield with atmospheric patterns (weather types, WTs) in the western Mediterranean basin. For this purpose, we analyzed a large database of rainfall events collected between 1985 and 2015 in 46 experimental plots and catchments with the aim to: (i) evaluate seasonal differences in the contribution of rainfall, runoff, and sediment yield produced by the WTs; and (ii) to analyze the seasonal efficiency of the different WTs (relation frequency and magnitude) related to rainfall, runoff, and sediment yield. The results indicate two different temporal patterns: the first weather type exhibits (during the cold period: autumn and winter) westerly flows that produce the highest rainfall, runoff, and sediment yield values throughout the territory; the second weather type exhibits easterly flows that predominate during the warm period (spring and summer) and it is located on the Mediterranean coast of the Iberian Peninsula. However, the cyclonic situations present high frequency throughout the whole year with a large influence extended around the western Mediterranean basin. Contrary, the anticyclonic situations, despite of its high frequency, do not contribute significantly to the total rainfall, runoff, and sediment (showing the lowest efficiency) because of atmospheric stability that currently characterize this atmospheric pattern. Our approach helps to better understand the relationship of WTs on the seasonal and spatial variability of rainfall, runoff and sediment yield with a regional scale based on the large dataset and number of soil erosion experimental stations.
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
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.
Open Access
Assessing hillslope-channel connectivity in an agricultural catchment using rare-earth oxide tracers and random forests models
(Universidad de la Rioja, 2017) Masselink, Rens Hein; Temme, A.J.A.M.; Giménez Díaz, Rafael; Casalí Sarasíbar, Javier; Keesstra, Saskia D.; Landa Ingeniaritza eta Proiektuak; Institute on Innovation and Sustainable Development in Food Chain - ISFOOD; Proyectos e Ingeniería Rural
Soil erosion from agricultural areas is a large problem because of off-site effects like the rapid filling of reservoirs. To mitigate the problem of sediments from agricultural areas reaching the channel, reservoirs and other surface areas it is important to understand hillslope-channel connectivity and catchment connectivity. To determine the functioning of hillslope-channel connectivity and the continuation of transport of these sediments in the channel, it is necessary to obtain data on sediment transport from the hillslopes to the channels. Simultaneously, the factors that influence sediment export out of the catchment need to be studied. For measuring hillslope-channel sediment connectivity, rare-earth oxide (REO) tracers were applied to a hillslope in an agricultural catchment in Navarre, Spain, preceding the winter of 2014-2015. The results showed that during the winter no sediment transport from the hillslope to the channel was detected. To test the implication of the REO results at the catchment scale, two contrasting conceptual models for sediment connectivity were assessed using a random forest (RF) machine learning method. The RF method was applied using a 15-year period of measured sediment output at the catchment scale. One model proposes that small events provide sediment for large events, while the other proposes that only large events cause sediment detachment and small events subsequently remove these sediments from near and in the channel. For sediment yield prediction of small events, variables related to large preceding events were the most important. The model for large events underperformed and, therefore, we could not draw any immediate conclusions whether small events influence the amount of sediment exported during large events. Both REO tracers and RF method showed that low intensity events do not contribute any sediments from the hillslopes to the channel in Latxaga catchment. Sediment dynamics are dominated by sediment mobilization during large (high intensity) events. Sediments are for a large part exported during those events, but the system shows a memory of the occurrence of these large events, suggesting that large amounts of sediments are deposited in and near the channel after these events. These sediments are gradually removed by small events. To better understand the delivery if sediments to the channel and how large and small events influence each other, more field data on hillslope-channel connectivity and within-channel sediment dynamics is necessary.
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
Photogrammetrical and field measurement of gullies with contrasting morphology
(Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, 2007) Marzolff, I.; Giménez Díaz, Rafael; Seeger, M.; Campo-Bescós, Miguel; Ries, J. B.; Casalí Sarasíbar, Javier; Álvarez Mozos, Jesús; Proyectos e Ingeniería Rural; Landa Ingeniaritza eta Proiektuak
Despite a wealth of studies on monitoring different types of gullies by using remote-sensing technique such as photogrammetry, relatively few efforts have been made to test their accuracy. Therefore the question arises as to what extent the accuracy of gully monitoring using photogrammetric technique depends on gully morphology. The objective of this work is to investigate this issue. To do that, we confront field measurements of cross-sectional areas of gullies with contrasting morphology with a similar dataset obtained using photogrammetry. Below, we present the first findings of this investigation.
Open Access
Factors controlling sediment export in a small agricultural watershed in Navarre (Spain)
(Elsevier, 2012) Giménez Díaz, Rafael; Casalí Sarasíbar, Javier; Grande Esteban, Ildefonso; Díez Beregaña, Javier; Campo-Bescós, Miguel; Álvarez Mozos, Jesús; Goñi Garatea, Mikel; Proyectos e Ingeniería Rural; Landa Ingeniaritza eta Proiektuak; Gestión de Empresas; Enpresen Kudeaketa; Gobierno de Navarra / Nafarroako Gobernua
It is recognised that the hydrological and erosion processes in watersheds are very much conditioned by the (inter)action of a number of variables. This paper covers a 15-year period of studying those factors that have a major influence on the sediment yield and transport during individual hydrological events in a small Mediterranean agricultural watershed. Multivariate statistical techniques such as cluster analysis and principal component analysis were applied for the interpretation of datasets. In addition, the relationships between suspended sediment concentration and discharge (hysteretic loops) were also analysed. The hydrological response of the studied watershed is mainly controlled by the antecedent condition of the flow. Most of the runoff and sediment are generated during the wet season when vegetation cover is scant and saturation overland flow occurs promptly as a response to almost any rainfall events. In contrast, during the dry seasons even if high-intensity rainfalls normally occur, very scant runoffs are, however recorded, at the exit of the watershed. Most of the eroded sediment seems to come from riparian areas. The discharge registered at the watershed outlet up to 1 h prior to the flood is a very good surrogate for antecedent soil moisture.
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
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
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.