Main Geomorphological Features Research Articles

Geomorphological analysis of the Antinaco‐Los Colorados valley, La Rioja province, Argentina

AbstractThe Antinaco‐Los Colorados valley (ALCV) is a tectonic depression located in the centre‐north of the province of La Rioja (Argentina), limited to both the east and west by mountain ranges, in the broken foreland region. Geomorphological research on environmental dynamics is important for both building a reference framework for further studies and for the development of the socio‐economic activities in the area. This study presents the main geomorphological features of the tectonic depression at the regional scale in order to identify the primary factors involved in its evolution and the landforms it contains. The ALCV is asymmetric, and it is filled by up to 1600 m of sediments along the western margin. Using literature, images, digital elevation models of the study area and field work, different morphologies were identified in the valley, mostly linked to Quaternary climatic and tectonic changes. These morphologies were grouped into three main morphogenetic units that characterize this landscape: the relict piedmont levels, the current piedmont and the fluvial‐aeolian plain. The identification of fluvial forms suggests that fluvial systems have been important during the evolution of the landscape. Aeolian accumulation features, currently mostly vegetated, were likely formed under drier climatic conditions than those at present and probably related to the last ice age or even more recent times. Successive reactivations of the overall system are not only tectonic, as evidenced by the structural lineaments that affect relict piedmont levels and the fluvial‐aeolian plain, but also climatic. Thus, the identified landforms suggest that climatic and tectonic variables account for the variations in the environment of the ALCV, affecting the reaccommodation of the exogenous geomorphological processes and the modelling of the relief.

Hadal zones of the Southwest Pacific and east Indian oceans

The hadal zone (water depths > 6000 m) are unlike the overlying shallower marine regions (bathyal and abyssal) as it does not follow a continuum from the continental shelves to abyssal plains, but rather exhibits a globally disjunct series of discrete deep-sea habitats confined within geomorphological features. From an ecological perspective, hadal communities are often endemic to individual or adjacent features and are partitioned and isolated by geomorphological structures. To examine the size, shape, depth and degree of isolation of features where hadal fauna inhabit, this study explores the broad seafloor geomorphology, and distinctly partitioned hadal areas, across the Southwest Pacific and East Indian oceans using global bathymetric datasets. This research revealed the area occupied by hadal depths to be 716,915 km2 of which 58% are accounted for by trenches, 37% in basins and troughs, and 5% fracture zones. The largest feature in terms of area > 6000 m depth is the Wharton Basin with 218,030 km2 spanning 376 discrete areas. The largest continuous hadal habitats were the Kermadec and Tonga trenches at 145,103 and 111,951 km2 respectively, whereas features such as the Java Trench comprise two hadal components partitioned by a bathymetric high. Conversely, no physical barrier exists between the New Britain and Bougainville trenches thus any literature pertaining to hadal species or habitats from these trenches can be merged. This study highlights that the hadal zone mainly comprises two main geomorphological features (trenches and basins) that differ in size, depth and complexity. Hadal basins cover vast, generally shallower areas, comparable to abyssal plains, whereas trenches, despite a lesser footprint, represent greater depth ranges and complexity. As such, sampling designs and interpretation of ecological data must differ and hadal basins likely play an increasingly important role in understanding ecological shifts from abyssal to hadal ecosystems.

Comprehensive Methodology and Analysis to Determine the Environmental Flow Regime in the Temporary Stream “La Yerbabuena” in Aguascalientes, Mexico

In this study, a comprehensive methodology was adapted to determine the environmental flow regime of “La Yerbabuena”, a temporary stream located in the Aguascalientes Valley, Mexico. The analysis was divided into four stages: the geomorphological watershed analysis, a hydrologic analysis, hydraulic modeling, and environmental analysis. The main geomorphological features of the study area were defined from maps in the spatial block, and with them, a synthetic series of daily and monthly discharge was determined and further used in the next stages. In the hydrological stage, the IHA (Indicators of Hydrologic Alteration) methodology and the procedures from the Mexican regulation, named NMX-159, were applied to the stream, and their results were comparatively analyzed. A similar interannual flow variation from both methodologies was found for wet and dry seasons, ranging from 0.010 to 0.108 m3/s. In the hydraulic modeling stage, a micro-basin part of the stream was modeled in the software HEC RAS, observing that the IHA methodology results had water levels that matched the baseflow of the stream, which allows understanding the hydraulic behavior of the water flow through the generation of different profiles in function of the rainy season. Finally, for the environmental stage, the hydrological health of the stream was evaluated using the software Flow Health, additionally observing that the IHA methodology was closer to the desired water level of the reference. This study demonstrates that the proposed methodology achieves the objectives defined by the NMX-159, which establishes a streamflow regime considering a natural interval of hydrologic variability in both ordinary and after-disturbance conditions. This application of the methodology for temporary streams provides an understanding of the hydrological behavior of the environmental flow throughout the year, and regarding the existing regulations, it presents a correlation with the obtained results, as well as greater precision in the dry season.

Deep-Seated Gravitational Slope Deformations in Molise region (Italy): novel inventory and main geomorphological features

ABSTRACT This paper focuses on Deep-Seated Gravitational Slope Deformations (DSGSDs) identified in the Molise region (Italy), along the central-southern sector of the Apennines chain. These phenomena were detected and mapped through a combination of aerial-photo interpretation, morphological analyses, and field surveys, integrated through satellite SAR interferometry (InSAR). The obtained general map is organized in different sections: inventory map with identification of DSGSDs and main geological and orographic features, geostructural scheme, representative cross sections, list and characteristics of DSGSDs, geomorphometric maps, landslides map, and seismotectonic setting. This study allowed us to realize a complete inventory of DSGSDs in the Molise region and define the main characteristics of each phenomenon. Through this research, it was possible to establish a general correlation between the analyzed deformations and the geological and geomorphological setting of the region as well as with its geodynamic context.

Deep-Seated Gravitational Slope Deformation in Molise region (Italy): Novel inventory and main geomorphological features

Deep-Seated Gravitational Slope Deformation in Molise region (Italy): Novel inventory and main geomorphological features

Morphological, hydrodynamic and sedimentary characteristics of the Northeastern coast of Cuba

The absence of the marine platform, the presence of emerged and submerged terraces with tide notches on its front face and the increase in the number of beaches constituted by terrigenous sands towards the east end of this coastal stretch are the main geomorphological features that characterize the northeastern coast of Cuba. The lower rocky terrace is the best represented type of coastline on the Northeastern coast, exposed to the direct action of ocean waves. Considering the inland coast, mangroves are the most abundant type of coast and occupy most of the bays on this coastal stretch. From the hydrodynamic point of view, the highest wave heights of the north coast of Cuba take place there. In addition, the biggest tidal range of the Cuban archipelago is recorded. From the sedimentary point of view, these beaches have a greater amount of fragments of mollusks and corals and fewer fragments of calcareous algae than the other beaches of the Cuban archipelago. These beaches, unlike the other beaches of Cuba, show cumulative processes at the end of winter and early spring, with a maximum accumulation in April, while eroding at the beginning of autumn, with maximum values in the months of September and October. Keywords: Coastal characteristic, beach, genesis sand, Northeastern coast of Cuba.

Remote sensing applications for the assessment of the geomorphic response of fluvial systems to the Holocene Climate Changes

During the Holocene, the Tigris-Euphrates river system (Lower Mesopotamian Plain) was characterized by a complex morphodynamic due to climatic fluctuations, shoreline shifting, and human activities. Within a wide and barren floodplain with low elevation ranges, a remote sensing multi-sensor approach is suitable to identify the main geomorphological features and associated geomorphic processes. Optical and multispectral imagery (TerraColor and Landsat 8) are adopted for the preliminary visual inspection and the computation of multispectral indices (NDVI and Clay Ratio), as well as for the supervised classification. The topographic analysis of the micro- relief is integrated reclassifying two DEMs (AW30D30 and GDEM2) to highlight the peculiar configuration of the drainage system, which channels are several meters above the surrounding floodplain. This approach allows the investigation of the study area through large and medium scale, identifying active and abandoned channels, discerning between active and abandoned avulsion processes and distinguishing crevasse channels, levees, and deposits. In like manner, human features are recognized, allowing the evaluation of human- environmental interactions.

Ecogeomorphology and vulnerability in a Mediterranean ria-type coast (La Maddalena Archipelago, NE Sardinia, western Mediterranean)

ABSTRACT This paper presents a map describing the main geomorphological and sedimentological features, hydrodynamics, benthic habitat distributions and human impact on the coastal and marine areas of the Archipelago of La Maddalena (NE Sardinia, western Mediterranean). This cartography is based on an interdisciplinary sea-land approach, with the aim being to support sustainable and successful beach management in the face of a changing climate and environment, thereby contributing to the achievement of the Agenda 2030 Sustainable Development Goals (13, 14 and 15). In the Main Map (1:14,000 scale), the static and dynamic features of the beach systems and adjacent inner shelf are divided into thematic sections that include the geomorphological elements, hydrodynamics, sedimentological distributions, benthic habitat (mainly Posidonia oceanica meadow) and anthropogenic impacts. The map establishes a fundamental, multidisciplinary benchmark that is able to provide substantial scientific support to policymakers in relation to future vulnerability-assessment activities and the definition of land-management strategies.

Geomorphological mapping as a tool for geoheritage inventory and geotourism promotion: a case study from the middle valley of the Marecchia River (northern Italy)

The aim of this paper is to present the geomorphological map of the right side of the middle Marecchia valley, in the northern Apennines (Italy), as a basis to enhance the geotouristic potential of the area. This area has been chosen because it is representative of the geological, geomorphological and geodynamic context characterizing the whole Marecchia basin, where a massive allochthonous body (known as Valmarecchia Nappe) widely outcrops. This area consists of Ligurian and Epiligurian formations that overthrust the Umbro-Marchean autochthonous units, drawing a peculiar landscape characterized by high geodiversity and marked above all by landforms developing into various formations. In order to map the main geomorphological features, multi-temporal aerial photos analysis, field survey and bibliographical research, concerning both the geomorphological and cultural values, have been carried out. The landforms highlighted in the map include stream terraces, vertical cliffs, alluvial fans, badlands and landslides; additional geomorphological points of interest have been described and mapped as they represent the most distinctive events in the area. The geomorphological features have been integrated with the additional (ecological, aesthetic, cultural) values to quantify the value of each geosite using an adapted version of Reynard et al. (2016)’s method, from which it emerged that the sites have high scores both in terms of scientific and additional values, making the study area an ideal territory in which implement actions and proposals for geotouristic fruition.

Geomorphological Heritage Attractions Proposed for Geotourism in Asir Mountains, Saudi Arabia

This study is going to deal with attractions proposed by the geomorphological heritage in Asir Mountains. The reason behind conducting this study is for presenting the abilities of geo-tourism development in Asir Mountains. The geomorphological heritage embraces landforms and processes playing a key role in the understanding the history of earth and having a strict relationship with both the geomorphological and cultural heritage. The geomorphological heritage is unique and distinctive within the geo-heritage and has promoted great interest over time from a touristic viewpoint. Geomorphological heritage is more than ever in a position to become a significant sustainable territorial resource, enhanced through geo-tourism. A heritage geomorphology emerges, which are not only the characterization of the geomorphological heritage, but also methods of protection and management. In order to analyze geomorphological features of this area and to achieve a digital map, a GIS database created by using both of topographic and lithological maps and satellite images. Using these datasets, the main geomorphologic features extracted and realized based on two stages. First stage is consisted of field campaigns to collect morphological information, and selection of significant geomorphologic sites was based on field survey and study of relevant literature, which chose ten geomorphologic sites. The second one achieved the map of landforms that have geo-touristic potentials in the study area. As a result of this study, the main geomorphological heritage sites were extracted; these geosites can help to interest of the geotourism attractions in Asir Mountains. All these geosites should be conserved and developed to maintain and protect natural and geological attractions while supporting the geotourism for the use of scientists and students and tourists and other casual recreationalists in Asir Mountains.

Sand Ridges on Rocky Coastal Platforms as Markers of Tsunami Impact: A Multi-Disciplinary Analysis along the Ionian Coast of Southern Apulia (Italy)

Along the Ionian coast of Southern Apulia, a sand ridge has been detected at the inner border of a wide, low-elevated rocky platform. A multi-disciplinary analysis was carried out to define the main geomorphological and sedimentological features of this dune-like coastal deposit, to clarify its nature as well as to obtain chronological constraints for its development. The geomorphological survey reveals that the sand ridge is about 40–60 m wide, reaching a maximum elevation of 3.9 m above m.s.l., whereas its thickness can be estimated between 1.0 and 2.8 m. The sand ridge is in some places associated with large-size boulders. Grain size analysis shows that it is made up of poorly sorted coarse-medium sands with a gravelly fraction, without significant sedimentary structures, as confirmed by Ground Penetrating Radar survey. The micro and macro-faunal assemblage sampled in the sand ridge can be related to shallow-water environments with Posidonia oceanica meadows occurring offshore. The development of the studied sand ridge can be ascribed to a tsunami event able to mix up very coarse bioclastic sands placed at submerged platforms, storm beach deposits covering the low-elevated coastal platform in patches, and possibly older tsunami deposits. Accelerator Mass Spectometry radiocarbon age determinations on mollusc shells sampled from the sand ridge span from 929–1168 AD to 1707–1950 AD and cluster around the 18th–19th centuries, suggesting a possible association with a recent tsunami event. Data reported in the Euro-Mediterranean Tsunami Catalogue would indicate as the most likely event that one of the 25th April 1836, produced by a strong earthquake with its epicenter near Rossano village, on the Ionian coast of the Calabria region.

Morphology of fore-reef slopes and terraces, Takapoto Atoll (Tuamotu Archipelago, French Polynesia, central Pacific): The tectonic, sea-level and coral-growth control

A dataset of 41 bathymetric profiles detected by satelline imagery and echo-sounding to a maximum depth of 38 m along the fore-reef slopes of Takapoto Atoll (Tuamotu Plateau, French Polynesia, central Pacific) were qualitatively and quantitatively analyzed in order to identify the main geomorphological features. In addition, scuba-diving investigations from a selected site resulted in defining coral composition and cover rate. Six distinct fore-reef sectors were morphologically differentiated on the basis of seaward extension and slope gradient. Only the north end, and a restricted area of the mid-south-east side extend seawards over an average distance of 150 m, with a relatively low gradient (23°–38°). Most of the outer-slope areas are narrow (<100 m on average) and steep (average slope equals to 45° to up to 70°). Geomorphic features include spur-and-groove systems, sub-horizontal to gently dipping terraces (23–45 m wide) ending seawards in vertical steps (<10 m high) and drop-offs (>10 m high), outer-reef crest-like reliefs (0.5 m–1.5 m high), pinnacles (2 m–17 m high), coral heads (<2 m high), trenchs and concave scars. The recognized seven terrace levels occur at the respective depths of about −5 m, −10 m, −15 m, −20 m, −24 m, −30.5 m and −38 m. Based on comparison with subsurface chronostratigraphy of drilled reef sequences from some other Pacific atolls, the terraces are interpreted as remnants of reef tracts formed during Pleistocene interglacial, high sea-stands, respectively during MIS substage 5e (about −125 ka), MIS substages 7a (about −195 ka), 7c (about −210 ka), 7e (about −240 ka) and 9e (−330 ka). After depth correction of ground lowering during periods of emergence and subsidence effects, terrace elevations were expected to indicate eustatic sea-level positions at each identified high sea-stand, at approximately 7 m (MIS 5e) and 2.2 m (MIS 7a) above present sea level and 9.5 m (MIS 7c), 11 m (MIS 7e) and 8.6 m (MIS 9e) below present sea level. During the post-glacial sea-level rise, from about 9.5 ky, the studied portions of fore-reef slopes were re-flooded. It was assumed that coralgal deposits in the form of thin veneers, coral heads, outer-reef crest-like reliefs and pinnacles have simply overlapped pre-existing structures. Locally, the fore-reef zones are carved by trenchs, i.e. incipient detachment faults, and scars, i.e. imprints of former landslides. Similarly, some drop-offs may be regarded as fault walls. The prevailing direction of faulting–collapsing surfaces is consistent with the SW–NE orientation of the main axis of the atoll and submarine ridges rising up from the north-western floor of the Tuamotu Plateau. Analysis of the composition and distribution of coral communities to −30 m depth revealed high, downslope-increasing coral coverage (24% to 67% on average) and the sharp replacement of robust-encrusting Pocillopora by sub-massive to plate-like Porites from depths greater than −10 m. Significant inter-regional differences were detected with atolls in west Pacific, probably due to local ecological constraints.

Population genetic structure of the whorl-leaf watermilfoil Myriophyllum verticillatum shaped by topography and geographic distance

Interpopulation gene flow plays an important role in determining population genetic structure. In this study, we sampled 24 populations of the whorl-leaf watermilfoil Myriophyllum verticillatum from three disjunct regions in China (Northwest China, Northeast China, and the Qinghai-Tibet Plateau (QTP) plus Southwest China) with different topographies and examined its population genetic structure using 17 microsatellite loci. Deserts, plains, and mountains are the main geomorphological features of Northwest China, Northeast China, and the QTP plus Southwest China, respectively. High genetic differentiation and genetic isolation by geographic distance were observed at the overall scale and in all three regions. When compared among the three regions, the lowest level of genetic differentiation and weakest correlation between genetic and geographic distances were presented in Northeast China. Two genetic clusters corresponding to Northwest China and the other two regions were identified, suggesting unequal gene flow among the three disjunct regions. Our findings emphasize the role of topography and geographic distance in shaping population genetic structure in aquatic plants.

Potential educational use of geomorphological units and landforms

The inventory of the geological heritage of the state of São Paulo, Brazil, was carried out from 2012 to 2015 and resulted in the selection of 142 geosites in 11 geological frameworks representative of its geological history. Among the frameworks is the “Geomorphological units and landforms”, which includes fourteen geosites representative of the main geomorphological features in the area. Since these kinds of geosites are very suitable to interpretative and educational purposes, in this work we present both qualitative and quantitative assessments of the potential educational use of the geosites present in this geological framework. The assessment was carried out using the GEOSSIT platform, which was developed by the Geological Survey of Brazil (CPRM). The outcomes of the quantitative assessment made it possible to rank the geosites according to their importance. The geosites Jaraguá Peak and Itapeva Peak achieved the highest rankings, a result that reinforces their current use for tourist activities; on the other hand, the geosites Jureia Massif and Diabo Hill were the lowest ranked. The data obtained in this study suggest the need to establish educational measures that may increase activities of valorisation, dissemination and conservation of these geosites, and that take into account the geodiversity elements. In order to implement such measures, some support from public and private agencies is fundamental. In general, geosites present excellent conditions for the dissemination of geoscientific knowledge, making a key to the construction of a geoconservation conscience by the general public.

Landslide inventory and main geomorphological features affecting slope stability in the Picentino river basin (Campania, southern Italy)

ABSTRACT The landslide inventory of the Picentino basin was realized at 1:25,000, with focus on main geomorphological features affecting slope stability. It is based on different sets of air-photos (scales 1:33,000–1:18,000, dated up to 1998), and on field surveys. Among shallow landslides, channelized debris flows strongly prevail, originated as debris slides on moderately steep slopes. Further sectors are affected by deeper slope movements of greater extent. Items related to tectonics, erosion processes, and anthropized sectors are also mapped. Relevant predisposing factors to slope instability are shown in 1:100,000 thematic maps. In addition, shallow landslides of the 1998 inventory were compared to those derived from two event-based inventories (PSAI 2002, PSAI 2011, dated 1998–2005 at 1:13,000–1:10,000). Discrepancies are mainly ascribable to types of employed air-photos, age of surveys, scale of mapping, and freshness of forms, remarking the relevance of suitable shallow-landslide inventories for susceptibility evaluations.

Geomorphology, lithofacies, and block characteristics to determine the origin, and mobility, of a debris avalanche deposit at Apacheta-Aguilucho Volcanic Complex (AAVC), northern Chile

Understanding the evolution of a volcanic edifice is important in establishing its associated geological hazards. Apacheta and Aguilucho volcanoes, northern Chile, formed a volcanic complex with known fumaroles and geothermal potential. Among the products resulting from the evolution of the Apacheta-Aguilucho Volcanic Complex (AAVC), a new volcanoclastic deposit has been recognized towards the eastern flank of the volcanic complex. This deposit is constituted by fragments of andesitic-to-dacitic lava and hydrothermally altered lava blocks. These fragments, which reach up to 5m in diameter, form geomorphological structures such as hummocks, levées and ridges. Using these geomorphological characteristics, the distribution of the main lithological facies (or lithofacies), and fragment features (jigsaw cracks and impact marks), we proposed that this deposit was generated by a debris avalanche. This debris avalanche was triggered by partial collapse of an ancestral volcanic edifice occurred between 100 and 700ka. The collapse of the AAVC ancestral edifice was influenced by hydrothermal alteration and the extensional tectonic setting that characterize the Cerro Pabellon Dome area. The mobility of the avalanche, and the genesis of the main geomorphological features associated with the deposit, are related to fragmentation of material during avalanche genesis and movement.

Ancient settlement dynamics and predictive archaeological models for the Metapontum coastal area in Basilicata, southern Italy: from geomorphological survey to spatial analysis

In the ancient territory of the Greek settlement of Metaponto and its Chora (Ionian sector of Basilicata, southern Italy) geomorphological mapping, GIS-supported statistics, and landform topographic features were investigated and combined to extract settlement rules and site dynamics. Analyses of environmental dynamics as well as of spatial and temporal settlement evolution were carried through an integrated approach that, starting from a detailed geomorphological analysis, tried to extract the spatial relationships between archaeological site locations and landform/landscape features. Spatial analysis was used to investigate the relationships between environmental parameters and archaeological sites. The advantages to develop a predictive model using Archeological Spatial Evaluation (ASE) analysis lay in the possibility to deeply study the relationships between man and the environment. In the present study, the analysis was carried out in a pioneering way in the ~400 km2 Metaponto territory in order to robustly validate - in the aftermath data - human and territorial dynamics. A model describing interactions between sites and parameters such as elevation, slope, aspect, landforms, land use, and distances from rivers was constructed. Sensibility maps were produced, which will help archaeologists to know how many and which are the parameters increasing the probability to find new archaeological sites as well as how the main geomorphological features of the study area, contextualized within the most likely paleoclimate scenario, affect ancient site arrangement though time. The preferential occupation of mid-altitude marine terraces, and the consequence spreading of agriculture on these territories, is likely due to the existence of well-developed soil profiles on them. Clearly colonists recognized that on these landform units there were the better conditions for the development of massive agricultural practices: since the SP age (4,1 to 2,0 Kyr B.P.) the settlers expands inland looking for most fertile territories as well as for areas sufficiently protected (being far away from the coast). The increase in farmhouses on the top of marine terraces from the FC up to EC-EE periods and the modifications of settlement distribution (gradual abandonment of alluvial) in the Metaponto area is likely related to the acceleration of alluvial processes. The progressive decrease of human occupation during the Hellenistic up to the Roman Age is clearly consequence of the Roman conquest. However, a role played by the increase in flooding occurrence in the coastal plain/floodplains of the main rivers in triggering the abandonment of these territories and marking the beginning of the decadent phases should not be neglected. Productive areas (locally associated to farmhouses) are preferential set along the fluvial incisions (sometime associated to farmhouses), thus implying that productive area setting is strongly linked to the presence of rivers, and of their lower rank tributaries, both as an intrinsic need of manufacturing and to facilitate the spreading of products. From the Classical to the Hellenistic Age until the Roman Age, Necropolis are spread in the entire area, from marine terraces to alluvial plain. On the other hand, Sacred areas - which appearance is recorded starting from the Colony Foundation Age - exhibits a settlement continuity in the study area starting from this time up to the entire Roman period, and the sacred areas setting is strictly associated to the category of Settlement.

GEOMORPHIC CONSTRAINS ON THE EVOLUTION OF THE AGGITIS RIVER BASIN NORTHERN GREECE (A PRELIMINARY REPORT)

In this paper we discuss the landscape evolution of the Aggitis River basin by correlating the morphological characteristics of the Maaras Cave (Aggitis River spring) with the main geomorphological features of the Aggitis fluvial valley. We combine the various morphological features that are hidden inside the Maaras Cave with the surface geomorphology of the river valley in order to trace the imprint of the different evolutionary stages on the landscape. Also, we provide a relative chronological framework for the evolution of the area. The 3D survey of the Maaras Cave shows that the roof of the cave is looping-like shaped in contrast to the floor of the cave that shows low slopes and holds thick clastic sediment deposits. Furthermore, the geomorphological mapping of the Aggitis River valley shows two prominent windgaps at the southern part of the basin that formed as the result of river capture. Our results suggest that the Aggitis River basin suffered four major evolutionary stages from the Neogene until the Quaternary.

Historical Coastal Evolution and Dune Vegetation in Isla Salamanca National Park, Colombia

ABSTRACT Gomez, J.F.; Byrne, M.-L.; Hamilton, J., and Isla, F., 2017. Historical coastal evolution and dune vegetation in Isla Salamanca National Park, Colombia. This paper analyzes the relationship between coastal dynamics and vegetation over dunes in Isla Salamanca Road Park (ISRP), a biosphere reserve and Ramsar site located on the Colombian Caribbean coast. Historical coastline changes together with the main geomorphological features were surveyed through fieldwork, satellite images, and historical aerial photographs, revealing that erosion is the predominant process in the eastern and central sectors of ISRP, and accreting trends throughout time occur in the westernmost sector of the study area. Dunes in the central and eastern sectors are scarped and regularly affected by storm wave action, whereas on the western end of the study area, embryo dunes are currently forming and evolving. Based on the mapped landforms and coastline trends for the last six decades, 1-square-m quadrats were used to identif...

Spatial and Temporal Distribution of Soil Moisture at the Catchment Scale Using Remotely-Sensed Energy Fluxes

Despite playing a critical role in the division of precipitation between runoff and infiltration, soil moisture (SM) is difficult to estimate at the catchment scale and at frequent time steps, as is required by many hydrological, erosion and flood simulation models. In this work, an integrated methodology is described to estimate SM at the root zone, based on the remotely-sensed evaporative fraction (Λ) and ancillary information on soil and meteorology. A time series of Terra MODIS satellite images was used to estimate SM maps with an eight-day time step at a 250-m spatial resolution for three diverse catchments in Europe. The study of the resulting SM maps shows that their spatial variability follows the pattern of land cover types and the main geomorphological features of the catchment, and their temporal pattern follows the distribution of rain events, with the exception of irrigated land. Field surveys provided in situ measurements to validate the SM maps’ accuracy, which proved to be variable according to site and season. In addition, several factors were analyzed in order to explain the variation in the accuracy, and it was shown that the land cover type, the soil texture class, the temporal difference between the datasets’ acquisition and the presence of rain events during the measurements played a significant role, rather than the often referred to scale difference between in situ and satellite observations. Therefore, the proposed methodology can be used operationally to estimate SM maps at the catchment scale, with a 250-m spatial resolution and an eight-day time step.