Coastal Basins Research Articles

Assessment of satellite precipitation products at different time scales over a cyclone prone coastal river basin in India

Abstract Precipitation is a fundamental input for many hydrological and water management studies. With the advancement in science, a variety of satellite precipitation products are available. In this study, the ability of three satellite precipitation products (TRMM-3B42v7, PERSIANN-CDR and GPM-IMERGv6) to capture rainfall were evaluated with ground-based Indian Meteorological Department (IMD) gridded data and also by driving the Soil Water Assessment Tool (SWAT) hydrological model for a cyclone prone coastal river basin in the southeast of India. Results indicate that among the three, GPM-IMERG v6 outperformed in all the statistical metrics, followed by TRMM-3B42 v7 at different temporal scales. GPM-IMERG v6 exhibited the highest correlation coefficient (0.48) and lowest root mean square error (9.52 mm/day), followed by TRMM-3B42 v7 (CC = 0.44, RMSE = 9.58 mm/day) at daily scale. In contrast to other studies in similar regions, IMERGV6 showed better performance than the PERSIANN CDR in detection skills of low, medium and high intensity rainfall events as well as False Alarm Ratio. Hydrological evaluation of the three products using the SWAT model over the study area showed satisfactory results at daily and monthly scale during the calibration and validation period. IMERGV6 is found to have better performance in hydrological evaluation as well.

Simulation and Evaluation of Water Resources Management Scenarios Under Climate Change for Adaptive Management of Coastal Agricultural Watersheds

The main objective of this paper is to analyze the impact of climate change on water resources management and groundwater quantity and quality in the coastal agricultural Almyros Basin, in Greece. Intensive groundwater abstractions for irrigation and nitrogen fertilization for crop production maximization, have caused a large water deficit, nitrate pollution, as well as seawater intrusion in the Almyros aquifer system. Multi-model climate projections for Representative Concentration Pathways (RCPs 4.5 and 8.5) from the Med-CORDEX database for precipitation and temperature have been used to evaluate the impacts of climate change on the study area. The multi-model climate projections have been bias-corrected with Delta, Delta change of Mean and Variance, Quantile Delta Change, Quantile Empirical Mapping, and Quantile Gamma Mapping methods, and statistically tested to find the best GCM/RCM multi-model ensemble. Simulation of coastal water resources has been performed using an Integrated Modelling System (IMS) that contains connected models of surface hydrology (UTHBAL), groundwater hydrology (MODFLOW), nitrate leaching/crop growth (REPIC), nitrate pollution (MT3DMS), and seawater intrusion (SEAWAT). The results indicate that the best climate multi-model ensemble consists of three (3) climate models for both RCP4.5 and RCP8.5 using the Quantile Empirical Mapping bias-correction method. The IMS was applied for historical and future periods with observed and simulated meteorological inputs (e.g. precipitation and temperature) and various irrigation and agronomic scenarios and water storage works development (i.e. reservoirs). The results indicate that at least deficit irrigation and deficit irrigation along with rain-fed cultivation schemes, combined with or without the development and operation of reservoirs, should be applied to overcome the degradation of groundwater quality and quantity in the study basin. Based on the findings of this work, the water resources management should be adaptive to tackle the water resources problems of the Almyros Basin.

Spatial-temporal dynamic impact of changes in rainfall erosivity and vegetation coverage on soil erosion in the Eastern Mediterranean.

In Syria, soil erosion (SoEr) by water is one of the major challenges for sustainability. Thus, the main goals of this research were to evaluate the spatial changes of SoEr between 2000 and 2018 in the whole coastal basin (CB) of Syria and to provide a soil water erosion risk map for the study area. For this purpose, monthly rainfall data, the SoilGrids dataset, satellite image derived NDVI layers, and Digital Elevation Model (DEM) were collected. Through the integration of these layers into the Revised Universal Soil Loss Equation (RUSLE), under a Geographic Information System (GIS), soil loss was assessed. Also, the contribution of land cover changes and R factor on SoEr were evaluated. The outcomes of this assessment illustrated that the R factor ranged from 800 to 2600MJmmha-1h-1yr-1, while the soil erodibility factor (K factor) ranged from 0.048 to 0.035 ton ha MJ-1mm-1. The C factor (vegetation coverage) values ranged between 0.07 and 1 with a spatial average value of 0.44 for the 2000-2009 period and 0.39 for the 2010-2018 interval. The output of RUSLE revealed that average annual SoEr was of 21.35 ton ha-1 y-1 (± 38) for 2000-2009 and 22.47 ton ha-1 y-1(± 41.8) for 2010-2018. Interestingly, the increased SoEr caused by the R factor was dominant (34.65%), followed by changes in both C factor and R factor (13.34%). However, decrease of SoEr rates is due to the increase of the C factor accounting for 36.82% of the CB. The outcome of this research can provide constructive spatial insights for rehabilitation plans for the post-war phase of Syria.

CHANGES IN PHYSICAL ENVIRONMENT OF THE SOUTHWESTERN COASTAL BANGLADESH: A RIVER BASIN APPROACH

This study deals with the nature and state of geomorphic environmental changes of a coastal river basin at southwestern Bangladesh over a period of three decades (1973-2009). The study concentrates on the Kholpetua river basin, which receive fresh water flow from Betna in the upstream and tidal flow in the middle from Morichapa and finally drains to the Bay of Bengal through Kapotakshi River. The whole Kholpetua basin may be divided into three distinct parts: fresh water upstream, brackish water middle part and saline lower part.
 Large-scale population increase, both in the upper and middle basin; infrastructure development, in the form of road network and introduction of HYV rice in the floodplain of Betna and shrimp farming on the brackish water have lead to the loss of both quality and extent of wetland resources in the basin area, endangering the geomorphological balance in terms of input and output between upstream and downstream. A large section of Betna has dried-up, and most of the tributaries and distributaries of the Morichapa have been silted up, partly because of extensive polders of the sub-basin. As a result, energy exchange (through tide) between basin plains and channels ways has lost vitality.
 Multi-spectral remote sensing data, in conjunction with topographical maps and ancillary data analysis reveals that throughout the basin, a wide range of anthropogenic interference have physically altered the characteristic ecosystem of the basin. The agricultural land is about 79,395 ha. in 1973, which is reduced at about 53,328 ha in 2009. With 1779 to 2001, a strip of about 20 km wide mangrove forest has been disappeared. Such physical alteration has been initiated with the poldering of middle brackish water part of the basin and later with the introduction of extensive shrimp cultivation. Attempt has been made to explore the linkage of upstream landuse activities and drainage alteration to the hydrological and geomorphological behavior of the downstream basin areas, extrapolate ecological sensitivity of the basin.

Morpho-bathymetric acoustic surveys as a tool for mapping traces of anthropogenic activities on the seafloor: The case study of the Taranto area, southern Italy

In this study, an investigation procedure for mapping the traces of anthropogenic activities on the seafloor is proposed. Analyses are based on the interpretation of acoustic data (Multibeam Echosounder and Side Scan Sonar) acquired in the Taranto coastal area. Specific GIS tools supported the acoustic data analysis, interpretation, and mapping. These analyses highlighted that the seafloor of both coastal basins included in the investigated area is affected by a high distribution of traces related to different anthropogenic activities such as dredging, shipping, and mussel farming activities. Such kind of traces resulted efficiently detectable from morpho-bathymetric acoustic data. In particular, groove traces resulted highly distributed in both basins, while sunken mussel farm facilities are widely distributed in the Mar Grande basin. The results highlight as acoustic surveys represent a useful tool for orienting effective coastal management actions. This study points out how geophysical surveys support the geo-environmental characterization of highly urbanized coastal sectors.

지석묘의 축조와 경관의 역사

In this study, first we reviewed the change of the archaeological perspectives on what it is like to be a dolmen, and attempted to interpret the distribution, location, and arrangement of burial facilities of Dolmen groups distributed in Haman Basin. Early Korean archaeologists in the 1930s and 1940s saw dolmens as cultural markers of an chronological period. Since then, dolmens have been regarded as evidence defining a stage of social evolution until the 1980s, but recently, they have been studied from the perspective of identifying them as monuments within a certain landscape. Although the dolmen groups in Haman basin do not overlap with the daily residence, there is a clear tendency to be built in a place not far from the daily residence group. Unlike the adjacent Namgang River valley or the southern coastal basins, a large-scale ritual complex had not been built, and instead, dolmens have been intensively built near the village. The dolmens in Haman are clearly arranged in a row, and it is highly likely to be the result of being arranged along the daily route of the residents. In particular, in the valley bottom plain, which is formed long from north to south, the line of dolmens arranged along the river can be said to be the result of the repeated constructions and rituals for hundreds of years. It is necessary to understand these dolmens as specific places in the landscape. The place where the dolmen were built has community experience and historical narratives, so it has the ability to recall memories. In particular, a place is created through the construction of monument architecture and the burial of objects with a specific meaning, and the materiality of buildings or burial objects accumulates memories of individuals and groups, and historical narratives are recalled for a long time. Since personal and community experiences and memories have been deposited in the dolmen group of Haman Basin, it can be interpreted as a monument that remains as a current material trace as historical narratives have been extended for a long time.

Experimental Modelling of an Isolated WECfarm Real-Time Controllable Heaving Point Absorber Wave Energy Converter

To offer point absorber wave energy converters (WECs) as a bankable product on the marine renewable energy market, multiple WECs will be installed together in an array configuration. The wave energy community (research and industrial) has identified the urgent need for available realistic and reliable data on WEC array tests in order to perform a better WEC array optimization approach and in order to validate recently developed (non-linear) numerical models. The ‘WECfarm’ project is initiated to cover this scientific gap on necessary experimental data. The ‘WECfarm’ experimental setup consists of an array of five generic heaving point-absorber WECs. The WECs are equipped with a permanent magnet synchronous motor (PMSM), addressing the need for WEC array tests with an accurate and actively controllable power take-off (PTO). The WEC array control and data acquisition are realized with a Speedgoat Performance real-time target machine, offering the possibility to implement advanced WEC array control strategies in the MATLAB-Simulink environment. The presented article describes the experimental setup, the performed tests and the results of the test campaign using a single, isolated ‘WECfarm’ WEC in April 2021 at the wave basin of Aalborg University (AAU), Denmark. A Coulomb and viscous friction model is determined to partly compensate for the drivetrain (motor, gearbox, rack and pinion) friction. A system identification (SID) approach is adopted considering the WEC system to be composed of two single input single output (SISO) models, the radiation and the excitation model. Radiation tests yield the intrinsic impedance. Excitation tests yield the excitation frequency response function. Adopting an impedance matching approach, the control parameters for the resistive and reactive controller are determined from the complex conjugate of the intrinsic impedance. Both controllers are tested for a selection of regular wave conditions. The performed experimental test campaign using an isolated ‘WECfarm’ WEC allows a full evaluation of the WEC design prior to extending the setup to five WECs. Within the ‘WECfarm’ project, an experimental campaign with a five-WEC array in the Coastal and Ocean Basin (COB) in Ostend, Belgium, is under preparation.

Thermal tolerance and critical maxima examined in marine gastropods inhabiting around Karachi Nuclear Power Plant

Bensthic communities along the coastal basins are an indication of ecosystem health but highly susceptible owing to manmade activities. This study envisages thermal tolerance in sea snailsMonodonta canalifera,Nerita albicillaandTylothais savignyiinhabiting around the outfall and intake structures of Karachi Nuclear Power Plant (KANUPP). To test the adaptability and vulnerability, a lethality test protocol under controlled temperature was applied in the laboratory where they were exposed at 25, 30, 35, and 40°C, which was raised to 45°C after an acclimation period of 1 week. The critical thermal maximum (CTmax) for the three species was found to be between 39 and 42°C, whereas the lethal temperature (LT50) tests revealed that at the utmost 45°C was lethal forM. canalifera. The correlation between LT50and CTmaxima(R= 0.47,p= 0.00) and LT50and body sizes reveals that the thermal adaptability inN. albicillaandT. savignyi(R= 0.65,p= 0.00) was relatively higher than that at 45°C given in the laboratory. In addition, microscopic changes due to temperature, which appeared in the foot (adhesive part) of each species, were deduced from the histological examination. The outcomes of this study would help to underline the ecosystem health around KANUPP and highlight precautionary measures required for the newly established K2/K3 power units to safeguard habitat.

The mitochondrial gene COI reveals the origin of the introduction of Platanichthys platana (Regan, 1917) (Clupeiformes, Clupeidae) in a neotropical floodplain

AbstractThe first records of Platanichthys platana in the upper Rio Paraná floodplain (URPF) date to 2012, but variations in the body length of specimens collected from this basin have since generated uncertainty about their identity and origin of introduction. This study aimed to genetically characterize populations of P. platana in different river basins, assess haplotype diversity, and determine the origin of the introduced population in the URPF. Sequences from the COI region were used to calculate genetic distances, construct gene trees, and identify haplotype networks. Eight haplotypes were found, several of which were exclusive to the coastal basins of Santa Catarina and Rio Grande do Sul, and the Río Negro basin (Río Yí). The Río de La Plata and Mar Chiquita basins, and upper Rio Paraná floodplain shared haplotypes. Based on the results of our analysis, we concluded that the URPF specimens were introduced from populations in Argentina.

Biostratigraphy and paleoenvironment correlation based on benthic foraminifera from the cenozoic Marajó and Pirabas formations, Eastern Amazon Coast, Brazil

The Oligocene-Miocene foraminifera biostratigraphy correlation has been applied successfully as a geological tool for establishing the paleoenvironmental conditions during the deposition of siliciclastic and carbonate strata in the Eastern Amazon coastal basins. In this region, previously interpreted tectonic compartments represented by the Marajó Basin and Bragantina Platform were the main sites of siliciclastic and carbonate sedimentation influenced by Late Paleogene-Neogene transgressive–regressive events. In the subsident Marajó basin, a siliciclastic estuary was developed, supplied by the Cratonic Amazon River. The transcontinental river did not influence the Bragantina region to the East, allowing the implantation of a shallow carbonate platform. These Neogene segments require further sedimentological, stratigraphic, and paleontological studies to define these limits. The use of foraminifera content has been considered an important tool to assist in this differentiation, providing a paleoenvironmental and paleoecological reconstruction model. This work used qualitative and quantitative analyses integrating several diversity indices, complementing the R-mode cluster and the correlation of planktonic and benthic (P/B) ratios. The similarity in faunal diversity indicated that these siliciclastic and carbonate units represented by the Marajó and Pirabas formations are chronocorrelated. Marajó Formation is interpreted as a restricted, suboxic, marginal marine environment (lagoons/mangroves) with variable salinity and abundance of the species as Cribroelphidium williamsoni, Ammonia tepida, and A. beccari. In contrast, the Pirabas Formation was deposited in a brackish, oxic, and carbonate platform characterized by Cibicidoides subhaidingerii, Cibicides pachyderma A. beccarii, and Cassidulina laevigata species. These foraminifera assemblages confirm the previous stratigraphic and paleoenvironmental interpretations providing new insights into understanding the Late Paleogene-Neogene evolution of the Eastern Amazonia Coast.

The Importance of Prevention in Tackling Desertification: An Approach to Anticipate Risks of Degradation in Coastal Aquifers

Groundwater degradation is a major issue on an increasingly hot and thirsty planet. The problem is critical in drylands, where recharge rates are low and groundwater is the only reliable resource in a context of water scarcity and stress. Aquifer depletion and contamination is a process of desertification. Land Degradation Neutrality is regarded as the main initiative to tackle land degradation and desertification. It is embedded in target 15.3 of the Sustainable Development Goals and focused on preventing these dynamics. Within this framework, we present an approach to assess risks of degradation and desertification in coastal basins with aquifers threatened by seawater intrusion. The approach utilizes an integrated system dynamics model representing the main relationships between the aquifer and an intensively irrigated area (greenhouses) driven by short- and medium-term profitability. The study area is located in a semi-arid region in Southern Spain, the Gualchos stream basin, which contains the Castell de Ferro aquifer. We found that the risk of salinization of the aquifer is 73%, while there is a 70% risk that the system would increases its demand for surface water in the future, and the chance of doubling the current demand is almost 50%. If the current system of reservoirs in the area were not able to satisfy such an increase in demand because of climate change, the basin would be at a serious risk of desertification.

River flooding on the French Mediterranean coast and its relation to climate and land use change over the past two millennia

River flooding triggered by extreme rainfall events is a major natural hazard that frequently causes fatalities and damages in southeastern France. A 2000-year record of flooding from the Hérault River basin was reconstructed using magnetic susceptibility data from lagoon deposits, supported by documentary databases of floods in coastal river basins from Languedoc over the last centuries. Flooding was particularly important between 800 and 1350 cal CE, i.e. during the warm climatic conditions of the Medieval Climate Anomaly. Moreover, several periods of increased flooding occurred in the 2nd, 6th-7th, 16th, 18th and 20th centuries. Increased flooding was significantly correlated with higher air temperature in the northwestern Mediterranean and with higher sea surface temperature in the Gulf of Lions. The analysis of relationships between river flooding and atmospheric conditions shows that autumn flood events in Languedoc were generally more frequent during the positive phase of the East Atlantic pattern, which is associated with southerly to southeasterly winds in the Gulf of Lions. Besides, increased flooding could also have been controlled by forest decline and human activities after 500 cal CE. Between 1400 and 1800 cal CE, palaeobotanical data show an intensification of land use characterized by an expansion of grasslands and cultivated areas in the coastal lowlands east of the Hérault River. Forest clearings and the development of agriculture seem to have led to a relative increase in river flooding, especially in the late Middle Ages and early modern period.

A century of anthropogenic river alterations in a highly diverse river coastal basin: Effects on fish assemblages

The global increase in human population is driving a continuous conversion of land to anthropogenic uses. This is a major threat to lotic ecosystems worldwide, as it compromises the biotic integrity and health of rivers and streams. Studies in the northern hemisphere have shown that the effects of urbanization on fish assemblages include decrease and/or loss of diversity and abundance of native species, and a proliferation of tolerant exotic species. Such effects have not been widely studied in developing countries like Chile, where urbanization has impacted several river ecosystems. Over decades, the lower zone of the Andalién River in Central Chile has gone over intense non-planned urbanization stemming from the city of Concepción, leading to several physical alterations. The native fish and lamprey fauna of this coastal river basin has been reported as very diverse, with a total of 16 native species. However, this fauna has been affected by multiple effects of different land uses and direct alterations in the riverbed. To study how these fish and lamprey assemblages have changed, this paper compiles records from 1919 to 2018 and analyzes them in relation to the direct and indirect anthropogenic alterations in the basin. The results show a significant reduction in richness and abundance of native species, with only nine species currently. The two migratory lampreys, one of them endemic (Mordacia lapicida), have been extirpated from the Andalién River basin. Conversely, the richness and distribution of introduced species has increased throughout the river basin. The invasive species Gambusia holbrooki, first registered in 1999, is currently the most abundant in the urban zone of the river. Although the more substantial direct alterations of the riverbed occurred in the lower areas, a steeper reduction in native species richness occurred in the middle areas subjected to a long history of agricultural and forestry land use. We suggest the loss of resilience of the river ecosystem, and that the collapse of biodiversity in this river system demonstrates the lack of urban planning and the inefficiency of environmental regulations in protecting native species and ecosystems with high conservation value in Chile.

Contrasting thermal histories for the Indian passive margins during syn‐ and post‐Gondwana break‐up: Insights from apatite fission‐track thermochronology

AbstractNew and published apatite fission‐track data provides evidence for differential exhumation between the eastern and western passive margins of southern India. The eastern margin records significant Late Jurassic to Early Cretaceous rifting‐triggered exhumation in response to Gondwana break‐up and minor Cenozoic cooling. In contrast, Meso–Cenozoic rifting and posterior tectonic events did not deeply exhume the basement of the western margin. The anomalous thick crust of the Western Dharwar Craton might explain why Mesozoic deformation in this area was subdued. In addition, the Cenozoic eastward tilting of the Indian plate and the onset of Bengal Fan sedimentation ca. 23 Ma allowed the accumulation of thick sedimentary sequences in the eastern coastal basins, probably inducing a flexural response of fault reactivation on the eastern margin. More generally, we demonstrate the influence of lithospheric strength and post‐rifting sedimentation to the exhumation history of passive margins.

Broad-scale eDNA sampling for describing aquatic species distributions in running waters: Pacific lamprey Entosphenus tridentatus in the upper Snake River, USA.

One of the most fundamental yet challenging tasks for aquatic ecologists is to precisely delineate the range of species, particularly those that are broadly distributed, require specialized sampling methods, and may be simultaneously declining and increasing in different portions of their range. An exemplar is the Pacific lamprey Entosphenus tridentatus, a jawless anadromous fish of conservation concern that is actively managed in many coastal basins in western North America. To efficiently determine its distribution across the accessible 56,168 km of the upper Snake River basin in the north-western United States, we first delimited potential habitat by using predictions from a species distribution model based on conventionally collected historical data and from the distribution of a potential surrogate, Chinook salmon Oncorhynchus tshawytscha, which yielded a potential habitat network of 10,615 km. Within this area, we conducted a two-stage environmental DNA survey involving 394 new samples and 187 archived samples collected by professional biologists and citizen scientists using a single, standardized method from 2015 to 2021. We estimated that Pacific lamprey occupied 1875 km of lotic habitat in this basin, of which 1444 km may have been influenced by recent translocation efforts. Pacific lamprey DNA was consistently present throughout most river main stems, although detections became weaker or less frequent in the largest and warmest downstream channels and near their headwater extent. Pacific lamprey were detected in nearly all stocked tributaries, but there was no evidence of indigenous populations in such habitats. There was evidence of post-stocking movement because detections were 1.8-36.0km upstream from release sites. By crafting a model-driven spatial sampling template and executing an eDNA-based sampling campaign led by professionals and volunteers, supplemented by previously collected samples, we established a benchmark for understanding the current range of Pacific lamprey across a large portion of its range in the interior Columbia River basin. This approach could be tailored to refine range estimates for other wide-ranging aquatic species of conservation concern.

The response of metal mobilization and redistribution to reoxygenation in Baltic Sea anoxic sediments.

To bring life back to anoxic coastal and sea basins, reoxygenation of anoxic/hypoxic zones has been proposed. This research focuses on the metals released during the oxidization of sediments from two locations in the anoxic Eastern Gotland Basin under a laboratory-scale study. Triplicate experimental cores and reference cores were collected from the North and South Eastern Gotland Basins. The oxygenation of the water column took place over a 96-hour experiment in a dark and 5 °C environment. In 12 and 24 hour intervals, the surface waters were exchanged and, over time, analyzed for pH, electroconductivity (EC), total organic carbon (TOC), soluble metal concentrations, and the top samples (0-10 cm) were analyzed with 3-step (E1: water-soluble, E2: exchangeable, and E3: organic-bound) sequential chemical extraction (SCE). Results show stable pH and decreasing EC in the column waters. The EC indicates that metals are released in the initial phases (12 h) of reoxygenation for both sites. Arsenic, Ba, Co, Mn, Rb, U, K, Sr, and Mo are released into the water column during the 96 hour experiment, and based on the calculations for the entire East Gotland Basin, would mean 8, 50, 0.55, 734, 53, 27, 347,178, 3468, and 156 μg L-1 are released, respectively. Elements Mn, Mo, U, and As are released in higher concentrations during the experiment than previously measured in the Eastern Gotland Basin, which provides vital information for future proposed remediation and natural geochemical processes with their known environmental impacts. The SCE results show that redox-sensitive metals (Mn, U, and Mo) are released in the highest concentrations into the solution. The relationship between the highest released metals (beside redox-sensitive) into solution over the oxygenation and their initial abundant phase is noticed, where the smallest released concentrations belong to K < Rb < Sr in E2, and As<Ba in E3, respectively.

Variables that induce coastal squeeze, case study: Ciudad del Carmen, Campeche, Mexico

Coastal squeeze describes a dynamic process in which sea level rise and concomitant variables (e.g., increased storms, coastal subsidence) shift coastal habitats to land. The presence of hard structures of anthropogenic origin along the coasts can also create static artificial margins between land and sea, restricting coastal habitats to a narrow area. Ground level rise with respect to the coastal plain, which can be caused by an interrupted hydro-sedimentary flow, can also form added natural barriers. In particular, the coast of Mexico is vulnerable to sea level rise, however, other faster processes could be inducing coastal oppression/squeeze to a greater extent, such as subsidence, extreme hydrometeorological phenomena, changes in land use and erosion derived from sediment retention in the upper coastal basins. The aim of this study is analyzed coastal oppression along the coast for Ciudad del Carmen, Campeche, Mexico, by finding its determining variables based on a literature review and analysis of open access databases. The processes analyzed correspond to changes in land use, the incidence of storms and the presence of hard structures, among other factors, which have increased rapidly in the study area in recent years and have caused the loss of coastal ecosystems. Ultimately, this work aims to generate a method that can quantitatively measure the effects of coastal oppression in different coastal areas. The resulting method serves as a tool for decision-making and sustainable coastal management. Keywords: coastal zone, land use change, incidence of storms, Gulf of Mexico, Campeche.

Spatio-temporal assessment of rainfall erosivity in Ecuador based on RUSLE using satellite-based high frequency GPM-IMERG precipitation data

Soil erosion caused by rainfall is one of the main soil degradation problems in Ecuador and has major implications on conservation and management of water and soil resources, disaster control, agricultural protection and other applications in the Ecuadorian territory. Extensive precipitation time series are required to estimate the rainfall erosivity as a triggering element of soil erosion, however, meteorological stations distribution in Ecuador is not homogeneous over the national territory (greater concentration in coastal basins) and present high lack of data, generating an incorrect rainfall distribution that requires resorting to other types of available information. The objective of this work was to analysis the spatio-temporal distribution of potential soil erosion through rainfall erosivity in Ecuador, through an innovative method based on the Revised Universal Soil Loss Equation (RUSLE) employing GPM-IMERG rainfall data. Our methodology considered the delimitation and evaluation of the watersheds environmental characteristics, GPM-IMERG, GPCC and ERG-data evaluation as providers of rainfall databases, and calculation of the erosive force of the rain (R-Factor) over the period 2001–2020. Basins delimitation and layers of environmental characteristics were obtained from regional literature; GPM-IMERG and GPCC from web servers; ERG-data from INAMHI-Ecuador; R-Factor (30 min) calculation was made from GPM-IMERG parameters and its was validated with RIST software using a representative subset of pixels, revealing an excellent compatibility of almost 1% average difference. New information was obtained from spatial, interannual and seasonal R-Factor distribution considering environmental characteristics, even though the satellite image products (GPM-IMERG) still underestimate the high values of R-Factor compared to Literature. New models for Ecuador have been established to estimate the R-Factor from annual rainfall, which allow it to be calculated since the beginning of the last century as well as generate projections of future soil erosion. This helps territory managers to take new measures to deal with soil loss.

On the generation of high‐resolution probabilistic design events capturing the joint occurrence of rainfall and storm surge in coastal basins

AbstractCoastal areas are subject to the joint risk associated with rainfall‐driven flooding and storm surge hazards. To capture this dependency and the compound nature of these hazards, bivariate modelling represents a straightforward and easy‐to‐implement approach that relies on observational records. Most existing applications focus on a single tide gauge–rain gauge/streamgauge combination, limiting the applicability of bivariate modelling to develop high‐resolution space–time design events that can be used to quantify the dynamic, that is, varying in space and time, compound flood hazard in coastal basins. Moreover, there is a need to recognize that not all extreme events always come from a single population, but can reflect a mixture of different generating mechanisms. Therefore, this paper describes an empirical approach to develop design storms with high‐resolution in space and time (i.e., ~5 km and hourly) for different joint annual exceedance probabilities. We also stratify extreme rainfall and storm surge events depending on whether they were caused by tropical cyclones (TCs) or not. We find that there are significant differences between the TC and non‐TC populations, with very different dependence structures that are missed if we treat all the events as coming from a single population. While we apply this methodology to one basin near Houston, Texas, our approach is general enough to make it applicable for any coastal basin exposed to compounding flood hazards from storm surge and rainfall‐induced flooding.

Well Log Lithological Analysis and Petrophysical Parameters Calculation of Miocene to Recent Formation Reservoirs in Well P10, Offshore, Northern Rio Del Rey Basin (Southwest Cameroon, Gulf of Guinea)

The P10 well is located offshore, in the Northern part of the Rio Del Rey basin in southwest Cameroon. Although the Rio Del Rey basin is the most prolific coastal basin in Cameroon given the production results from several fields in the southern part, yet it remains very little explored in its northern part. This work evaluation the petroleum potential in the northern part of the Basin using a combination of the &amp;quot;Quick Look&amp;quot; interpretation of the logs recorded in well P10 and &amp;quot;complex matrix&amp;quot; facies analysis of the different lithofacies through the neutron porosity - bulk density (NPHI-RHOB) and delta time sonic - bulk density (DT-RHOB) diagrams. The composite log includes the Gamma Ray log; Caliper log; Deep Resistivity log; neutron porosity log and bulk density log. In addition to this composite log, a geological end of well report is completed to refine the results. Ten (10) near sand/sandstone reservoirs were delineated between 950 and 1803 TVD m (true vertical depth in meter) with very good porosities (12% &amp;lt;&amp;Phi;&amp;lt; 30%) as well as a mineralogical composition dominated by quartz. Clay volumes are relatively lower than 18% except in reservoirs R5 and R6 where they are around 24%, giving the latter a sandy-clay lithology. Reservoirs R2 and R4 contain oil, the latter with a WOC (Water Oil Contact) at ~1172 m and a GOC (Gas Oil Contact) at 1169 m. Reservoirs R6; R7; R8; R9; R10 all contain Gas and Water with WGC (Water Gas Contact) located at ~1431 m; 1530 m; 1690 m and ~1790 m respectively. In the light of these results, there is a clear dominance of gaseous hydrocarbon reservoirs over oil-impregnated ones in the study area. The results provided by this work can serve as baseline data for future oil and gas exploration projects in the northern part of the Rio Del Ray Basin.