Authors:J. Bonsoms, F. Salvador-Franch, M. Oliva Pages: 291 - 307 Abstract: Snow cover has significant impacts on geoecological dynamics as well as on socio-economical systems. An accurate quantification of snow precipitation patterns in mountain regions is needed to better understand the spatio-temporal implications of snow cover. The objective of this work is to characterize the patterns of solid precipitation and snow cover in two high Mediterranean massifs. To this purpose, we analyse instrumental data series of snowfall and snow depth of Port del Comte (2316 m a.s.l.) and Cadí-Nord (2134 m). Both stations are situated in the eastern Pre-Pyrenees and include 14 consecutive snow seasons from November to May, allowing to (i) explore the dependence of the main drivers of snowpack: temperature and snowfall; (ii) find out the most frequent circulation weather types associated with high intensity snowfall events, and finally (iii) investigate the role of the North Atlantic Oceanic (NAO) teleconnection pattern explaining snow cover evolution during the winter season. Data show that snowfall is controlled by similar weather types in both stations that resulted in similar snowfall averages: 205 cm and 258 cm at Port del Comte and Cadí-Nord, respectively. Nevertheless, local factors interfere with the amount of snow depth recorded, which is moderately different between stations. Whereas Cadí-Nord records a seasonal mean of 66 cm, Port del Comte records a smaller quantity of 25 cm with a high interannual and seasonal variability. In fact, snowfall recurrence, snow amount or duration in the ground is considerably variable among years (CV>20). In these stations, snow cover duration is determined by the precipitation in the form of snow falling during the previous months. Snowfalls in moderate to severe episodes (>15 cm in 24 h) are mainly driven by Atlantic flows, mostly from NW. In addition, NAO pattern is negatively correlated with snowfall in November and December months (R>-0.50), showing a weaker and not statistically significant correlation during the rest of the winter season. PubDate: 2021-07-01 DOI: 10.18172/cig.4879 Issue No:Vol. 47, No. 2 (2021)
Authors:Ana Paula Forte, Cristian Daniel Villarroel, María Yanina Esper Angillieri Pages: 309 - 336 Abstract: This paper presents a detailed rock glacier and protalus rampart inventory from Las Salinas river basin, an arid subtropical mountain hydrological system (between 31°02’ and 31°22’ S latitude) located in the northern sector of the Central Andes of Argentina, where permafrost and cryogenic processes prevail. The inventory is based on a geomorphological characterization by means of optical remote sensing and field description data. The study region covers 630 km2, with 3.25% of the area containing 405±8.2 rock glaciers and protalus ramparts in total, of which 231±2.5 are considered protalus rampart and 49±2 are considered active, 61±1 inactive and 64±3 fossil rock glaciers. Frequency ratio and logistic regression were used as statistical methods to determine the relationship between the distribution of these periglacial landforms and different geological, morphometric and climatic variables as elevation, potential incoming solar radiation, slope, aspect and lithology. Results show that elevation, lithology, and aspect are the most influencing factors for the occurrence of active rock glaciers. According to rock glaciers and protalus ramparts distribution, the permafrost occurrence probability is above 3690 m a.s.l. (current and high periglacial environment). However, some inactive rock glaciers and protalus rampart were found below this elevation, thus between 3300 and 3690 m a.s.l. the landscapes are dominated by an unstable periglacial environment. PubDate: 2021-07-01 DOI: 10.18172/cig.4922 Issue No:Vol. 47, No. 2 (2021)
Authors:F.I. Contreras, G.M. Mavo Manstretta, M.C. Piccolo, G.M.E. Perillo Pages: 337 - 354 Abstract: Floods are recurring events in Buenos Aires Province, mainly caused by high-intensity precipitation, and in some cases, they persist for long periods. The objective of this study is to analyze how the topography of the central-western portion of Buenos Aires Province determines the occurrence and the extent of floods. The presence of shallow lakes characterizes the area which is controlled by the topography. LANDSAT 5 and 8 images corresponding to periods of drought and flooding in the area were compared with topographic profiles and digital elevation models generated from SRTM 3 arc/sec data. The results showed that in those areas where there are aligned dunes, and after significant storm drain engineering works, during the wet periods, the lakes, their overflows, and the subsequent runoff to the east of Buenos Aires Province flow freely, limiting the flood areas. Due to this topography, the lakes became a more permanent feature of the landscape, even during extreme drought events. In contrast, in those areas where parabolic dunes predominate, the landscape is more affected by droughts and floods. During drought events, we observed a small number of shallow lakes, and during strong storms with high-intensity rainfall, the number of lakes increases and large flooded areas generate damage to agricultural fields and neighboring cities, either due to natural causes or improvised and illegal storm drains. Early warning of flood risks and a systematic territorial ordaining would be the key to the management of the area. PubDate: 2021-07-01 DOI: 10.18172/cig.4477 Issue No:Vol. 47, No. 2 (2021)
Authors:C. Lauro, A. Vich, S.M. Moreiras, Luis Bastidas, S. Otta, E. Vaccarino Pages: 355 - 370 Abstract: The prediction of the maximum annual flow is necessary for flood management. Large amounts of hydrological information are required to make meaningful estimates. The Colorado River System basins have a topography that makes it difficult to maintain hydrometric stations, so there is a lack of continuity in records and in several cases there are ungauged basins. Regionalization methods consist of transferring information from gauged to ungauged sites in order to make predictions. The objective is to find regional regression models that relate the climate and morphometric characteristics of the basins with the maximum annual flow. For this purpose simple linear regression models were used. From this relationship and the regional frequency curve it will be possible to predict the maximum annual flows for different return periods in ungauged basins of the Colorado River System, Argentina. Regionalization models show that the best estimates occur when the predictor variable is the area and perimeter of the basin. Errors in the regionalization models of various sites in the system resulted between 6% and 67%. The models found are a tool for flood management in central-western Argentina. PubDate: 2021-07-01 DOI: 10.18172/cig.4465 Issue No:Vol. 47, No. 2 (2021)
Authors:A. Delapierre, J.A. Ballesteros-Canovas, J. Buzzi Marcos, V.I. Slaveykova, M. Stoffel Pages: 371 - 390 Abstract: Mining activity is often responsible for the drainage of acid or metal-enriched waters to fluvial systems. The release of metals is especially disturbing due to the toxicity and persistence of these products and their accumulation in the biosphere. Hence, a systematic detection and delimitation of highly polluted floodplains and linkages between pollution and high-flow stages would likely assist the improvement of land management and ease the design of mitigation or rehabilitation measures. Here we test how trees growing in different geomorphic positions along a fluvial system uptake metal during floods and how these uptakes can be documented “a posteriori”. To this end, we apply dendrogeochemical analyses to twenty Pinus pinaster Ait. trees growing on the banks of Odiel River (south-western Spain) as well as to five reference trees growing outside the river channel. In the field, trees were sampled with a large-diameter (1 cm) increment borer. In the lab, tree-ring series were dendrochronologically cross dated and separated into 5-yr blocks, so that wood blocks contained the dates of major floods. Then, Inductively Coupled Plasma Mass Spectrometry (ICPM) was employed to evaluate toxic metal concentrations in trees. Results point to clear correlations between the accumulation of toxic metals and the geomorphic position of trees within the fluvial network. We show that morphological units along a river exert control on toxic metal concentrations in trees, with uptake being much higher in trees located on meander cut banks than in trees growing on point-bar structures. Besides, we detect chemical signatures in trees located farthest away from the main river channel after the largest floods, but not in the aftermath of smaller events. We conclude that tree position is the single-most important determinant for metallic pollution in an environment controlled by fluvial processes, but also find that more studies are still needed to determine linkages with individual floods and interactions of metal uptake in roots via the water table in the river corridor. PubDate: 2021-07-01 DOI: 10.18172/cig.4740 Issue No:Vol. 47, No. 2 (2021)
Authors:M. Fojutowski, P. Gierszewski, D. Brykała, A. Bonk, M. Błaszkiewicz, M. Kramkowski Pages: 391 - 413 Abstract: Weather conditions and lake basin morphometry are of key importance in the study of sediment accumulation rate in lakes. This study aims to determine how these factors affect spatial and seasonal variations in sedimentation rate in the epilimnion and hypolimnion of Lake Gościąż. To determine sedimentation rates, six sedimentation traps were set up at different locations and depths in the lake. Weather data were obtained from a meteorological station near the lake. Furthermore, temperature in the lake water column was measured continuously, and during field work oxygenation and transparency were also measured. Seasonal changes in sediment composition were analyzed on smear slides under microscope. The study showed that sedimentation rate increased as bottom steepness increased, and that there was more sediment in the hypolimnion than the epilimnion, especially in spring and autumn. There was a clear seasonal variation in early-spring and autumn peaks in sedimentation. The obtained results were significantly dependent on bottom relief, wind and air temperature through these factors’ influence on water temperature. The results show that the sediment accumulation rate in Lake Gościąż depends on the hydrodynamic conditions, which are determined by wind speed, wind direction, water temperature, and the shape and steepness of the lake basin. The relief features of the lake bottom and its orientation relative to the prevailing wind are significant factors in the spatial differentiation in sediment accumulation rate and composition of sedimenting material. It has been shown that the lake’s shallow-water zone (littoral and sublittoral) is an important source of the material accumulated in the profundal zone. The patterns and mechanisms of the course of contemporary sedimentation in Lake Gościąż, as determined based on the conducted investigations, can be applied in the study of other lakes and in assessing the representativeness of sampling sites for laminated bottom sediments to be used in palaeo-environmental studies. PubDate: 2021-07-01 DOI: 10.18172/cig.4724 Issue No:Vol. 47, No. 2 (2021)
Authors:A. Tena, D. Vericat, R.J. Batalla Pages: 415 - 433 Abstract: The aim of this study was to build up a sediment budget of the Ribarroja Reservoir, which is located in the lower reach of the River Ebro. For this purpose, we analysed continuous discharge and suspended sediment transport data at several river sections entering the reservoir and at the dam outlet, for the period 2008-2011. The sediment load estimated upstream of the Mequinenza reservoir was 0.66×106 t a-1, whereas the estimated output was 0.04×106 t a-1. The sediment input coming from the large but highly regulated Pyrenean tributaries (Segre and Cinca) was 0.16×106 t a-1, whereas intermittent rivers naturally flowing from the Iberian Range (Matarraña and Algars) supplied an average load of 760 t a-1. The suspended sediment load trapped in the Mequinenza and Ribarroja reservoirs for the study period was estimated at 0.78×106 t a-1, which implies a reduction of ca. 95% of the sediment load of the river. The results illustrate the role of reservoirs in interrupting the sediment transfer in the lower reach of the Ebro, within a context of structural sediment deficit, following widespread land use changes (afforestation) that took place in the catchment after the 1940s. PubDate: 2021-07-01 DOI: 10.18172/cig.4894 Issue No:Vol. 47, No. 2 (2021)
Authors:A.M. Santana Cordero Pages: 435 - 455 Abstract: This paper explores the relationship in three sedimentary systems of the Canary Islands (Spain) between four major land change processes (resource extraction, urbanization, tourism and nature protection) and six main environmental consequences (impacts on aeolian sedimentary dynamics, changes in sand landforms, disappearance of sand landforms and entire systems, changes in vegetation, impacts on the socioeconomic system, and changes in land use patterns). The results show that all the environmental consequences have impacted all three study sites, except in one of them (La Graciosa island) in producing disappearance of sand landforms and entire systems. It should be noted that the environmental consequences described concerns different scales (from entire systems to landforms). All the impacts are described and analyzed separately, and the results are discussed in detail and in relation to the presence of these environmental consequences in other parts of the world. PubDate: 2021-07-01 DOI: 10.18172/cig.4932 Issue No:Vol. 47, No. 2 (2021)
Authors:M.B. Alfonso, A.S. Brendel, A.J. Vitale, M.C. Piccolo Pages: 457 - 475 Abstract: According to model projections, increases in the frequency and intensity of heatwaves are expected all over the world. This study analyzed, for the first time, the effect of heatwaves events on long-term surface latent (LE) and sensible heat fluxes (H) from two shallow lakes: La Salada lake (LS - 39°27′ S, 62°42′ W) and Sauce Grande lake (SG - 38°57′ S, 61°24′ W). The main drivers of LE and H are wind speed and direction, relative humidity, and the difference between air and water temperature. We found that the daily values of both fluxes were highly fluctuating. Mean daily H values ranged between -309.4 to 200.5 W m-2 and -78.6 to 104.8 W m-2 in LS and SG, respectively. LE oscillated between -152 and 463.9 W m-2 and between -59.2 and 360.1 W m-2 in LS and SG, respectively. Both fluxes decreased with the passage of heatwaves events, presenting a high variation in its amplitude. Changes up to 96% in mean daily LE and 671% in mean daily H for LS and up to 25% in LE and 987% in H for SG were accounted in days with heatwaves respect to regular ones. We analyzed the air temperature increase for both lakes under future global warming scenarios (RCP 4.5 y RCP 8.5), expecting higher amplitudes in heat fluxes. These results contribute to the development of lake models, as well as to water resources management in the future. PubDate: 2021-07-01 DOI: 10.18172/cig.4456 Issue No:Vol. 47, No. 2 (2021)
Authors:T. Lasanta, E. Nadal-Romero, M. Khorchani, A. Romero-Díaz Pages: 477 - 521 Abstract: Abandoned lands occupy extensive territories in some Spanish regions, particularly in mountain areas and semiarid environments. These lands originate very diverse landscapes depending on the climatic conditions, the age of abandonment, the management before and after abandonment, and the disturbances that they suffer during the post-abandoned process. These factors condition the plant succession and soil properties, producing contrasted ecosystems and landscapes, like forests, shrublands, grasslands and almost bare soils. This study reviews the current knowledge about land abandonment in Spain, with special reference to the spatial and temporal process of abandonment, the factors that originate different ecosystems, and landscapes in abandoned lands, and the implications of these factors in the provision of ecosystem services to society. Depending on the landscape generated and its management, different services would be provided, such as the quality and quantity of water resources, soil protection, carbon sequestration, levels of biodiversity, prevention and control of forest fires, pastoral resources, landscape aesthetics, and even the possibilities of securing population in the rural environment through extensive land uses. PubDate: 2021-07-01 DOI: 10.18172/cig.4755 Issue No:Vol. 47, No. 2 (2021)
Authors:F.J. Vázquez Pinillos, M.J. Marchena Gómez Pages: 523 - 543 Abstract: How can sea-level rise affect territory' Has territorial planning adjusted to this new situation' This paper analyses the possible ramifications of changes in tidal recurrence over the course of this century in a potentially vulnerable marsh environment, such as the Bay of Cádiz, in southern Spain, where sea-level rise is already a fact. For that purpose, the regionalisation criterion is used as a basis for adjusting the magnitude of global problems to subregional scale. Geographic information systems are applied to portray the forecasted territorial changes according to the RCP4.5 and RCP8.5 scenarios presented by the Intergovernmental Panel on Climate Change (IPCC) for the years 2050 and 2100. Projections of sea-level rise show that the tide is travelling farther inland, not just invading unoccupied areas of marshes and beaches but also reaching urban and productive areas. Estimates indicate that the floodable area could expand by more than 20% in 2050, with a further 2,000 ha of flooded areas added in 2100 for either of the two scenarios used. The occurrence of these changes, regardless of the model used, would therefore entail an alteration of the environmental, social, cultural and economic values and elements of the Bay of Cádiz, with the Natural Park being the most affected area. In response to these consequences, the need to apply the resulting projections to other variables is insisted on, with a view to introducing territorial management tailored to this new and already present reality. Application of the regionalisation criterion to study repercussions of the climate crisis in the Bay of Cádiz could serve as a precedent for the development of adaptation strategies in other marsh environments at subregional or local level. PubDate: 2021-07-01 DOI: 10.18172/cig.4531 Issue No:Vol. 47, No. 2 (2021)
Authors:P. Jokar, M. Masoudi, F. Karimi Pages: 545 - 556 Abstract: Geographic Information System (GIS) can be used in ecotourism as a decision support tool for sustainable tourism planning, impact assessment, visitor flow management, and tourism site selection. Therefore, this system has the potential to be widely applied in tourism. The purpose of the study was to explore the potential for ecotourism development using GIS in Sepidan region, placed in the southwestern part of Iran. An innovative method was proposed for adjusting effective parameters in evaluation of ecotourism. The methods used for evaluation comprised Boolean, current multi-criteria evaluation methods (weighted linear combination), and the proposed methods of geometric mean and its calibration. Results showed that an improved method using geometric mean (kappa= 0.72) was better than Boolean (kappa= 0.56) and multi-criteria evaluation (kappa= 0.59) models. The calibrated geometric mean was also the best among the different models used. It should be noted that the geometric mean method was simpler than multi-criteria evaluation and did not require the weighting process. PubDate: 2021-07-01 DOI: 10.18172/cig.4291 Issue No:Vol. 47, No. 2 (2021)
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