Analysis Of Digital Elevation Models Research Articles

Cultural geography meets architectural typology: a mixed-methods study of traditional Bayu dwellings in Southwestern China

ABSTRACT Traditional Bayu dwellings in China’s mountainous regions embody a rich yet underexplored architectural heritage, characterized by unique cultural and regional attributes. This study addresses the gap by investigating the architectural typologies, spatial distribution, and cultural influences of these dwellings. Employing a mixed-methods approach within the framework of cultural geography, the research integrates qualitative and quantitative methodologies. Data collection was conducted in three phases: (1) field surveys and documentation of 67 heritage-listed dwellings and 164 traditional villages; (2) collection of geographic data using GIS tools, including Digital Elevation Model (DEM) analysis; and (3) comprehensive literature review of historical and cultural records. Data analysis utilized statistical methods, including second-order cluster analysis, and spatial analysis with ArcGIS. The findings identify four primary dwelling types and delineate four architectural cultural zones shaped by geographical segregation, economic exchanges, and ethnic interactions. This study contributes to a broader understanding of the architectural culture and regional characteristics of the Bayu region, offering valuable insights for cultural heritage preservation and informing sustainable development strategies.

Investigation of Lineament Extraction: Analysis and Comparison of Digital Elevation Models in the Ait Semgane Region, Morocco

An automated lineament extraction model was successfully applied in the mountainous region of Ait Semgane, Morocco, enabling the identification of geological and tectonic linear features. Our research implemented several approaches including Topographic Position Index (TPI), shading, and Digital Elevation Models (DEMs), as input for the lineament extraction algorithm and applied to various Dems. We aimed to compare all of these strategies to determine the optimal method and the most favorable input DEM. Results revealed variable performance among methods, emphasizing the importance of choosing the optimum method based on specific objectives. TPI and Hillshade methods showed high sensitivity in detecting lineaments, while ALOS PALSAR and Sentinel 1 InSAR datasets were effective for subtle features. Lineament density exhibited specific orientations for highly-dissected zones, with TPI highlighting NE-SW and E-W orientations. Lineament orientations demonstrated consistency with established geology, confirming pre-existing tectonic knowledge. Cartographic analysis of faults emphasized the success of the SRTM DEM model with the TPI method, highlighting significant faults. Results also revealed a concentration of faults in the NW and southern sectors, corroborating bibliographic references and the well-documented tectonic setting of the study area. This automated methodology facilitated lineament extraction in unmapped areas, reinforcing the validity of the undertaken cartographic analysis.

Creating Sustainable Flood Maps Using Machine Learning and Free Remote Sensing Data in Unmapped Areas

This study leverages a Random Forest model to predict flood hazard in Arizona, New Mexico, Colorado, and Utah, focusing on enhancing sustainability in flood management. Utilizing the National Flood Hazard Layer (NFHL), an intricate flood map of Arizona was generated, with the Random Forest Classification algorithm assessing flood hazard for each grid cell. Weather variable predictions from TerraClimate were integrated with NFHL classifications and Digital Elevation Model (DEM) analyses, providing a comprehensive understanding of flood dynamics. The research highlights the model’s capability to predict flood hazard in areas lacking NFHL classifications, thereby supporting sustainable flood management by elucidating weather’s influence on flood hazard. This approach aligns with sustainable development goals by aiding in resilient infrastructure design and informed urban planning, reducing the impact of floods on communities. Despite recognizing constraints such as input data precision and the model’s potential limitations in capturing complex variable interactions, the methodology offers a robust framework for flood hazard evaluation in other regions. Integrating diverse data sources, this study presents a valuable tool for decision-makers, supporting sustainable practices, and enhancing the resilience of vulnerable regions against flood hazards. This integrated approach underscores the potential of advanced modeling techniques in promoting sustainability in environmental hazard management.

Glacial and periglacial geomorphology of the eastern flank of the north Patagonian Andes: Quaternary morphoclimatic evolution

The cold climate events of the Upper Cenozoic greatly modified the landscape of Patagonia, where a large number of relicts and active landforms of glacial, periglacial and paraglacial origin is preserved. To assess the regional paleoclimatic record when numerical ages are unavailable, the spatial distribution of local depositional landform sequences was analyzed in six mountain ranges located on the eastern margin of the North Patagonian Andes. The analysis of satellite images and digital elevation model, fieldwork research and its integration into a Geographical Information System were used to develop a detailed inventory of mountain landforms. A total of 67 glacial valleys, 97 glacial cirques, 94 moraines, 75 rock glaciers, 103 protalus ramparts, and more than 145 km2 and 100 km2 of surface affected by solifluction and mass wasting processes respectively were mapped. From the analysis of the spatial and altitudinal distribution of landforms, we defined temporal and spatial sequences of morpho-climate importance. We recognized four major morpho-climate events associated with local paleoclimate conditions and one stage of a recent paraglacial adjustment. The oldest cold climate event recognized might be correlated with the Last Glacial Maximum. The results show the rise in the average air temperature and an aridity trend for the study area since the Late Pleistocene. During this lapse, glacial environments evolved to periglacial environments, although was recognized their coexistence in some areas in the same mountain range.

From top to deep: An integrated multidisciplinary approach for the study of a transformative landscape of Savatra ancient city

AbstractIn this study, a combined workflow of computational methodologies is introduced to explore the transformative landscape of the ancient city of Savatra (Central Anatolia Region, Türkiye), which faces long‐term risks stemming from natural and anthropogenic threats. Emphasis was placed on regional and local scale landscape analysis, employing aerial and ground‐based remote‐sensing techniques to unravel past settlement patterns and understand the impact of environmental factors, topography and natural resources on both the location of Savatra and spatial organization of its features. On a regional scale, the influence of hydrological conditions, slope and aspect on the landscape was determined through the employment of Geographical Information System (GIS)‐based analysis of digital elevation models (DEMs). At a more local scale, the utilization of the Unmanned Aerial Systems‐derived DEM and geophysical survey helped identify potential archaeological features and also assessed the risk posed to these features. Furthermore, the incorporation of 3D GIS analysis, integrating 3D point cloud representations of the ground‐penetrating radar volume and DEM, provided essential insight into the state of preservation of the buried features. The collaborative application and joint interpretation of these methodologies yielded a wide range of clues and explanations, unravelling the complex palimpsest of past activities. This research not only serves as foundation for future studies specifically for Savatra, but also provides a preliminary remote sensing–based exploration blueprint to other yet to be studied archaeological sites.

Assessment of flash flood risks in the desert cities: a case study on Sabah Al-Ahmad, Kuwait

ABSTRACT Flash floods from rainstorms pose a severe natural hazard, especially dangerous in arid regions. This has occurred multiple times in Kuwait: in 1967, 1997, 2009, 2013, 2018, and 2020. For example, about 300 mm of rain beset the State of Kuwait on the 14th and 15th of November 2018. Subsequently, Sabah Al-Ahmad City was declared an environmental disaster zone, grappling with extensive water accumulation in its roads, urban zones, and surrounding valleys. This study focuses on (i) monitoring the hydro-geomorphological impacts of the floods on Sabah Al-Ahmad City and (ii) assessing the strategic plan to diminish flood risks, aiming to prevent a recurrence akin to the catastrophic events during rainstorms. (iii) proposing a protection plan for the city. The research employs various methodologies, including drones (UAV), field surveys, hydrological modelling, digital elevation model analysis, and spatial analysis of multi-spectral satellite imagery. These methods are instrumental in comprehending how flash floods impact the sustainable development of urban areas in Kuwait. Our approach is designed to support decision-makers and urban planners, enabling them to proactively identify flood-prone zones before future urban development initiatives in Kuwait.

Morphometric analysis of monogenetic volcanoes in the Garrotxa Volcanic Field, Iberian Peninsula

The Garrotxa Volcanic Field is situated in the northeast region of the Iberian Peninsula. It represents the most recent volcanic area within the Catalan Volcanic Zone, which is one of the volcanic provinces of the European Rift System, featuring over 50 dispersed eruptive vents.This study presents a comprehensive morphometric analysis of volcanic edifices, aiming to enhance our understanding of both volcanostratigraphy and the geomorphology of landforms within the Garrotxa Volcanic Field. Our methodology involved extensive fieldwork and detailed analysis of Digital Elevation Models (DEMs) to precisely determine the spatial distribution and morphometric parameters of the best-preserved volcanic structures in the area. The Garrotxa Volcanic Field exhibits an uneven spatial distribution of various volcanic landforms, with approximately 50 % comprising magmatic cones, primarily formed through Strombolian eruptions. The remaining 50 % is evenly divided between magmatic-phreatomagmatic volcanoes and phreatomagmatic tuff rings-maars. The morphometric characteristics of the three genetic types overlap significantly, showing no clear differences, although a few distinctions can sometimes be identified.The Garrotxa Volcanic Field displays a variety of eruption styles: 46 % of the identified eruptive sequences begin with phreatomagmatic activity, while 54 % start with predominantly magmatic explosive activity. Most eruptions show a transition through different phases.Data also indicate that the morphometric variability at the Garrotxa Volcanic Field stems from differences in the properties of pyroclastic sequences, resulting from their diverse eruption styles, as well as pre- and post-eruptive factors. Consequently, the results of the morphometric analysis are deemed insufficient for establishing a reliable chronology for the Garrotxa Volcanic Field.

Landslide type inference based on statistical analysis of a high-resolution digital elevation model in Gorce National Park, Poland

High-resolution digital elevation models are commonly utilized for detecting and classifying landslides. In this study, we aim to refine landslide detection and classification by analyzing the geometry of landslides using slope and aspect, coupled with descriptive statistics up to the fourth central moment (kurtosis). Employing the Monte Carlo method for creating terrain topography probability distributions and ANOVA tests for statistical validation, we analyzed 364 landslides in Gorce National Park, Poland, revealing significant kurtosis differences across landslide types and lithologies. This methodology offers a novel approach to landslide classification based on surface geometry, with implications for enhancing scientific research and improving landslide risk management strategies.

Информативность геоморфологических и изотопно-геохимических методов при оценке газоносности территории (на примере Ангаро-Ленской нефтегазоносной области)

The paper examines the geochemical method's effectiveness for assessing the gas potential of territories and prospecting for natural gas fields in combination with data on a territory's neotectonic activity obtained from the digital elevation model analysis in the Eastern Siberia area. Geochemical data include the content of methane and its homologues (C1 – C6), determined by gas chromatography in subsoil samples, as well as the carbon isotope ratio (δ 13C) of the detected methane, measured on an isotope mass spectrometer. The reconstruction of neotectonic activity areas was carried out using a modified morphometric method of digital elevation model analysis. Estimates of the macroscopic fracturing of the sedimentary cover, also caused by neotectonic activity, were obtained from the digital elevation model as the density of lines – primary linear objects expressed in relief, identified using the method of A. A. Zlatopolsky. The information obtained from the digital elevation model allows to identify areas where the probability of gas fields destruction is the highest. A joint analysis of isotope-geochemical data and information on the probable hydrocarbon deposits destruction makes it possible to assess the prospects for the territory's gas content, as well as identify promising areas.

Integrating remote sensing classification techniques for land use mapping in semi-arid regions: a case study of the Tamlouka basin, Algeria.

Worldwide, the majority of countries are actively devising strategies to address the challenges associated with unregulated and unmanageable development, the decline in environmental quality and the depletion of valuable agricultural land. This has led to a growing emphasis on understanding land use and land cover. In order to determine a better land use policy, legislators and planners need to know the current distribution of agricultural and urban lands, as well as information about changes in their proportions. Our approach combines data centred on main four themes-geology, slope gradient, hydrographic network and land use-in order to exploit classifier complementarities in our targeted agricultural study area of Tamlouka Basin, Algeria. Landsat 8 OLI-TIRs multispectral imagery and Shuttle Radar Topography Mission (SRTM-1arc v3) were used experimentally for classification and Digital Elevation Model (DEM) analysis. The classification's accuracy is confirmed by comparing the results of the decision tree classification with the validation samples. Results of the combination of several maps of classifications from the different methods show that the Tamlouka alluvial plain, having an area of 19,300 ha and an average slope gradient of less than 2°, drains the elevated reliefs that surround it via hydrographic network. The plain occupies 37% of the total basin area, with over of 60% being used for crop cultivation, regardless of fallow land areas in agricultural rotation at that time. The slope has been identified as a crucial factor determining land use patterns in the study area. This result can be used in prospective watershed management.

Computer model for detecting tsunami wave hazard on built-up land using machine learning and sentinel 2A satellite imagery

<p>The aim of this research is to compile a tsunami wave hazard scale based on built-up land density extracted and classified by machine learning from Sentinel 2A satellite and digital elevation model (DEM) imageries. This research was carried out in 5 stages, namely: (i) pre-processing of Sentinel 2A and DEM images, (ii) Classification of VI data using the machine learning algorithms, (iii) Spatial prediction using the ordinary kriging method, (iv) Field testing using the confusion matrix method, (v) Preparation of decision matrix for tsunami wave hazard. The results of the study show that the most accurate classification algorithm for classifying built-up indices data is the k-nearest neighbor (k-NN) algorithm. The results of the statistical accuracy test show that the most accurate is normalized difference built-up index (NDBI) with a mean of square error (MSE) value of 0.073 and a mean of absolute error (MAE) of 0.003. DEM analysis shows that the research area is at an altitude of 0–15 meters above sea level so it is in the high vulnerability to medium vulnerability category. Field testing showed user accuracy of 91.11%, manufacturer accuracy of 92.16%, and overall average accuracy of 91%.</p>

Glacial and volcanic landforms in the upper catchment of Claro River, Central Chile (35.5°S): A Late Quaternary geomorphological case study

AbstractThe upper catchment of the Claro river is located within the Transitional Southern Volcanic Zone in the Maule Region of Chile (35.5°S), at the foothills of Manantial Pelado volcano, a Pleistocene stratovolcano whose morphology suggests the occurrence of important glacial processes in the area. The observed glacial landforms can be sequenced and associated with episodes of volcanic activity. Different units of volcanic and glacial origin were identified based on field observations, detailed mapping, and digital elevation model and satellite image analysis. The contact relations between them made it possible to discern four events that can be linked to Marine Isotope Stages 8, 6, 4‐2, and to the Neoglacial. We propose seven stages in the geomorphological evolution from the late Pleistocene to the late Holocene, where there is coexistence between volcanic and glacial episodes, such as the emplacement of the Manantial Pelado volcano overlying the Abanico and Cola de Zorro formations; a subsequent debris avalanche; the enlargement of the Del Indio valley during the Penultimate Glaciation; the construction of Cerro Redondo (a minor eruptive center at the head of Del Indio valley); ongoing fluvial incision; and Neoglacial advances. The relative chronology proposed in this work contributes to clarifying the Pleistocene–Holocene geomorphological history in this catchment and to further understand the interplay between volcanic and glacial processes in the central Chilean Andes during the Quaternary.

The Role of Digital Elevation Models in Increasing the Accuracy of Geophysical Studies of Anthropogenic Metallic Pollution

The study focuses on improving the accuracy of geophysical investigations of anthropogenic metallic pollution using digital elevation models (DEMs). The methodology was tested at the Norilsk site, located in close proximity to the slag heaps of the nickel plant, based on DEM data obtained through unmanned aerial vehicles (UAVs) to conduct a detailed geomorphological analysis of the area. Geophysical methods such as the natural field (NF) method and frequency sounding were also used to identify zones of potential metallic pollution, as well as the characteristics and spatial positions of predicted permafrost layers. The main emphasis is on the advantages of integrating geophysical methods with DEMs and derived cartographic materials to improve the accuracy and reliability of surface metallic pollution detection and mapping, considering the geocryological situation within the study area. Geophysical methods of natural field (NF) and frequency sounding were employed to determine the geoelectrical properties of the study area. Reconnaissance surveys and flight missions were conducted to create the digital elevation model and orthoimage, and a surface water runoff map was developed based on the generated rasters and their interpretation. Based on the obtained geophysical data, zones of possible metallic pollution spread from the slag heaps were identified, which were confirmed through DEM analysis by the geomorphology of the study site. The distribution of specific electrical resistance fields was also interpreted in consideration of the collected data and validated through borehole drilling. It is worth noting that the integrated approach helped reveal the need to revise the interpretation plan, as only through the analysis of the nature and intensity of metallic pollution could the abnormally low resistance values in areas far from thermokarst lakes, with relatively shallow permafrost depths, be explained. Additionally, it became possible to qualitatively assess the zones of dust material accumulation.

The Pleistocene ice-sheet dynamics in north-central Poland based on magnetic fabrics of tills and landform analysis

Abstract This research was carried out in north-central Poland, which was occupied by the ice sheet of the Saalian (Marine Isotope Stage [MIS] 6) and Upper Stadial of the Weichselian (MIS 2) glaciation. The application of the anisotropy of magnetic susceptibility (AMS) method supported by a digital elevation model (DEM) analysis of the orientation of glacial landforms allowed for the reconstruction of ice-sheet extent and ice movement directions of these two Pleistocene glaciations. The research used an innovative method of collecting AMS till samples from the glacial plateau areas. Based on the research, it was found that during the general recession of the ice sheet of the Saalian glaciation, a previously undescribed glacial transgression occurred, characterized by a different direction of ice-sheet movement. On the basis of detailed geomorphological studies of the area of terminal moraines, previously described in fragments, the maximum extent of the ice sheet during the Weichselian glaciation was clarified. The recession of the ice sheet of the Weichselian glaciation from the area of north-central Poland took place in four regressive or transgressive–regressive stages with variable directions of ice-sheet movement. The results obtained indicate the great potential of the AMS method in paleoenvironmental studies of glaciated areas.

Performance Analysis of a Drone Development Kit-derived Digital Elevation Model

Surface modeling constitutes is a crucial aspect in numerous engineering inquiries and earth observation endeavors. In contemporary times, the acquisition of geospatial data essential for the digital representation of local regions is increasingly facilitated through drone-based methodologies, supplanting conventional terrestrial data gathering techniques. The market presently hosts a plethora of cost-effective, "ready-to-fly" unmanned aerial vehicles (UAVs), offering users the capability to generate photogrammetric outputs, including high geometric precision Digital Elevation Models (DEMs). Moreover, modularly structured drone development kits, designed for multifarious applications, are readily accessible for purchase. These drone kits offer an economically advantageous platform that users can customize to suit their specific needs. Nevertheless, the geometric precision of DEMs created using these kits hinges upon the capabilities of the imaging and navigation systems, in addition to the stabilization of the platform during autonomous flight. In this study, using a drone development kit and a commercial drone, simultaneous image acquisition was performed for the same study area and two different DEMs were produced. The efficacy of the DEM generated using the drone development kit was assessed through a comparative analysis with the DEM obtained from a commercial drone. In addition, geometric accuracy assessment was conducted for both DEMs using ground control points. The findings reveal the usability of drone development kits in precision DEM production, as well as their limitations.

INVESTIGATIONS ON INSAR DATA PROCESSING STANDARD FOR VOLCANO ISLAND MONITORING IN INDONESIA

Abstract. In critical situations such as disaster and humanitarian relief, the reliable geospatial data will present an appropriate decision on a timely manner. As fundamental datasets, large-scale topographic maps are are mandatory in order to perform geospatial analysis for many societal challenges. Indeed, Large Scale Topographic Mapping in Indonesia shall be accelerated in an innovative and productive way to consider the production efficiency, especially for the geospatial data acquisition as its primary source. Interferometric Synthetic Aperture Radar (InSAR) data acquisition presents some advantages, especially in conjunction with the security clearance and global weather as some main constraints for the geospatial data acquisition. In terms of disaster preparedness and emergency response, radar interferometry techniques can play an important role by generating a Digital Elevation Model (DEM) as an input to Decision Support Systems (DSS). In addition, the techniques of differential Interferometric Synthetic Aperture Radar (D-InSAR) can provide the earth surface deformation from time series Radar Datasets. A set of standards related to the InSAR data acquisition are essential, especially with regards to the improved sensors, and processing methods implemented by the worldwide space agencies nowadays. Hence, the precise definition of a standard is fundamental in order to prepare the InSAR data as one potential source of geospatial data and information, especially for LSTM data production. Generated time series of Digital Elevation Model (DEM) can identify the potential cause of 2018’s Sunda Strait tsunami (Tampubolon, 2019). It was related with the increasing eruption activity of Anak Krakatau (Child of Krakatoa). From DEM analysis, the Volcanic mudflow material avalanche has been detected before the tsunami hit the coastal surrounding area. In this paper, more advanced techniques was investigated by the combination between Time Series DEM Analysis and Ground Displacement detection. The focus on the integration between reliable TanDEM-X and up-to-date Sentinel 1A/B was proposed on another volcano island of Gamalama in Ternate. As TanDEM-X uses X-band as its medium wave, it can produce more reliable DEM as a reference data. On the other hand, Sentinel 1 uses C-band that can contribute to detect the ground deformation over the aforementioned volcano island. TanDEM-X uses a more robust and consistent approach to scan the earth surface by single data acquisition scheme, which is generally more accurate and reliable for the DEM generation. However, many factors influence the selection of a platform that can be best suited for radar interferometry. Initially, the German TanDEM-X Coregistered Singlelook Slant-range Complex (CoSSC) using bi-static InSAR approach has been implemented in order to generate DEMs comply with the LSTM specification in Indonesia. The basic principle is performing a simultaneous measurement of the same scene and identical doppler spectrum by using 2 sensors, thereby avoiding temporal decorrelation (DLR, 2012). Subsequently, the differential InSAR techniques by using Sentinel 1A/B has been performed in order to detect the ground deformation. Finally, tt can be shown that the reliable TanDEM-X data has increased the ground deformation resolution and accuracy in order to provide potential solution for disaster preparedness.

Land resource management on environment and sustained basis for agricultural land use planning using landform and land evaluation approach (a case study in North Barito District, Central Kalimantan Province)

One of strategic policies that has been established in order to achieve and maintain food security in Central Kalimantan is opening the potential lands for agriculture. North Barito district as one several districts in this province, with total areas of 998,908 hectares, has the availability of arable lands for agricultural development. This study was then carried out to provide data and information for appropriate land and environment management through proper agricultural land use planning. Landform approach through digital elevation model (DEM) analysis and land evaluation procedure were used to define land allocation on sustained basis. The technology of geographic information system (GIS) and remote sensing were also employed to produce geospatial data to support land evaluation purpose. The result provide geospatial management of land and environment concept that can be implemented as basic consideration for agricultural planning especially in land use. In the case of North Barito, the region can be allocated for agricultural system of estate crops, food crops and forest ecosystem with each total area of 558,319 hectares (55.89%); 221,920 hectares (22.22%); and 218,669 hectares (21.89%), respectively. Specific program and policy can then be designed to develop the region for the development of agricultural purposes.

A Toolbox for generalized pumped storage power station based on terrain in ArcGIS Environment

China proposed the goal of carbon peak by 2030 and carbon neutrality by 2060 at the 75th session of the United Nations General Assembly. Accelerating the development of clean energy is the key to achieve this carbon peak and neutrality goal. However, large-scale grid connection of new energy brings great challenges to the stable and safe operation of power grid. As a regulating power source and energy storage power source, pumped hydro energy storage (PHES) has strong regulating ability and is characterized as a reliable operation with broad prospects for development. However, the current field-survey-based method of site selection for PHES is time consuming, labour intensive, and costly. Improper site selection would cause ecological environment damages among other problems. A scheme or protocol that enables the automated site selection of PHES is therefore urgently required. The objective of this study was therefore to develop a new tool based on digital elevation model (DEM) and geographic information system (GIS) hydrological analysis function to screen out the potential PHES sites. ArcGIS, as a leading geospatial software, provides a set of geoprocessing (GP) tools for raster analysis. ArcPy is a Python package that runs in the ArcGIS environment. It can quickly invoke existing tools in ArcGIS to create custom extension modules. In this study, ArcPy was used to screen the site of PHES based on reservoir capacity and dam height, etc. Taking the southern Shaanxi Province, China as an example, comprehensive evaluation method integrating objective weighting method and multi-factor statistical analysis method is proposed and tested. This new method can promote the solution of the PHES site selection planning and preliminary reserve of PHES, and provide scientific reference and theoretical basis for the development and construction of PHES.

Shallow base metal exploration in northern New Brunswick, Canada

This research paper explores the effective utilization of 2-D Resistivity and Induced Polarization (IP) techniques for identifying sulfide deposits in complex geological settings. To enhance the accuracy of the findings, the geophysical data were complemented with geological information, petrophysical data, Digital Elevation Model (DEM), and Electromagnetic data Versatile Time Domain Electro-Magnetics (VTEM) and Total Magnetic Intensity (TMI) Reduced-To-Pole (RTP).The analysis of DEM, magnetic susceptibility, and magnetic intensity revealed a lack of correlation with the DEM, indicating that these parameters alone were insufficient to confirm the presence of sulfide deposits. Consequently, five regions exhibiting high to moderate conductivity were chosen for conducting six survey lines using the Wenner array with a 10 m electrode spacing. The objective was to map sulfide zones in Restigouche County, located in northeast New Brunswick.Geophysical measurements were acquired using a RESECS instrument, and the field data were processed using the Res2Dinv software after removing erroneous data points. Since the study area was characterized by thick overburdened glacial sediments and lacked surface exposure, information from numerous boreholes and core samples from the western part of the study area were utilized.The study achieved successful mapping of the shallow alteration zone containing pyrite mineralization in most of the survey lines. Specifically, resistivity responses below 50 Ω⋅m, coupled with high chargeability, likely corresponded to the alteration zone containing pyrite. Additionally, resistivity responses above 50 Ω⋅m, combined with chargeability and RTP readings, were indicative of the alteration zone with pyrite.

Simulation of Retrospective Morphological Channel Adjustments Using High-Resolution Differential Digital Elevation Models versus Predicted Sediment Delivery and Stream Power Variations

This work proposes a methodological approach applied to ephemeral gravel-bed streams to verify the change in the magnitude and frequency of hydrological events affecting the morphological dynamics and sediment budget in this type of channel. For the case study, the Azohía Rambla, located in southeastern Spain, was chosen, emphasizing the research on two reference riverbed sections (RCRs): an upper one, with a predominance of erosion, and a middle one, where processes of incision, transport, and deposition were involved. First, this approach focuses on relationships between peak discharges and sediment budgets during the period 2018–2022. For this purpose, water level measurements from pressure sensors, a One-Dimensional Hydrodynamic model, and findings from comparative analyses of high-resolution differential digital elevation models (HRDEM of Difference-HRDoD) based on SfM-MVS and LiDAR datasets were used. In a second phase, the GeoWEPP model was applied to the period 1996–2022 in order to simulate runoff and sediment yield at the event scale for the watersheds draining into both RCRs. During the calibration phase, a sensitivity analysis was carried out to detect the most influential parameters in the model and confirm its capacity to simulate peak flow and sediment delivery in the area described above. Values of NS (Nash–Sutcliffe efficiency) and PBIAS (percent bias) equal to 0.86 and 7.81%, respectively, were found in the calibration period, while these indices were 0.81 and −4.1% in the validation period. Finally, different event class patterns (ECPs) were established for the monitoring period (2018–2022), according to flow stage and morphological channel adjustments (overtopping, bankfull and sub-bankfull, and half-sub-bankfull), and then retrospectively extrapolated to stages of the prior simulated period (1996–2018) from their typical sequences (PECPs). The results revealed a significant increase in the number of events and PECPs leading to lower bed incision rates and higher vertical accretion, which denotes a progressive increase in bed armoring and bank erosion processes.