Sediment Data Research Articles

Ecogeochemistry of Mercury in Aquatic Organisms and their Habitat on the Territory of Moscow

The issue of technogenic mercury pollution of aquatic ecosystems in urban areas of Moscow was considered based on the sampling data of aquatic plants, amphibians and bottom sediments of the water bodies under study. Quantitative assessments of the mercury distribution in wild life and inorganic nature components of 33 water bodies of Moscow in both protected areas and beyond. Information was provided on the average percentage of mercury in some components of freshwater ecosystems. An excess of the average ecotoxicant concentration values in the in duckweed family (24 ng/g dry wt), amphibians (177 ng/g dry wt) and bottom sediments (57 ng/g dry wt) in the territory of Moscow was revealed versus bulk earth and background values. A significant correlation of mercury concentration for the natural components under study (R>0.4) was identified.

Identifying the acute toxicity of contaminated sediments using machine learning models

Ecological risk assessment of contaminated sediment has become a fundamental component of water quality management programs, supporting decision-making for management actions or prompting additional investigations. In this study, we proposed a machine learning (ML)-based approach to assess the ecological risk of contaminated sediment as an alternative to existing index-based methods and costly toxicity testing. The performance of three widely used index-based methods (the pollution load index, potential ecological risk index, and mean probable effect concentration) and three ML algorithms (random forest, support vector machine, and extreme gradient boosting [XGB]) were compared in their prediction of sediment toxicity using 327 nationwide data sets from Korea consisting of 14 sediment quality parameters and sediment toxicity testing data. We also compared the performances of classifiers and regressors in predicting the toxicity for each of RF, SVM, and XGB algorithms. For all algorithms, the classifiers poorly classified toxic and non-toxic samples due to limited information on the sediment composition and the small training dataset. The regressors with a given classification threshold provided better classification, with the XGB regressor outperforming the other models in the classification. A permutation feature importance analysis revealed that Cr, Cu, Pb, and Zn were major contributors to toxicity prediction. The ML-based approach has the potential to be even more useful in the future with the expected increase in available sediment data.

Spatial patterns of microbial diversity in Fe-Mn deposits and associated sediments in the Atlantic and Pacific oceans.

Mining of deep-sea Fe-Mn deposits will remove crusts and nodules from the seafloor. The growth of these minerals takes millions of years, yet little is known about their microbiome. Besides being key elements of the biogeochemical cycles and essential links of food and energy to deep-sea, microbes have been identified to affect manganese oxide formation. In this study, we determined the composition and diversity of Bacteria and Archaea in deep-sea Fe-Mn crusts, nodules, and associated sediments from two areas in the Atlantic Ocean, the Tropic Seamount and the Rio Grande Rise. Samples were collected using ROV and dredge in 2016 and 2018 oceanographic campaigns, and the 16S rRNA gene was sequenced using Illumina platform. Additionally, we compared our results with microbiome data of Fe-Mn crusts, nodules, and sediments from Clarion-Clipperton Zone and Takuyo-Daigo Seamount in the Pacific Ocean. We found that Atlantic seamounts harbor an unusual and unknown Fe-Mn deposit microbiome with lower diversity and richness compared to Pacific areas. Crusts and nodules from Atlantic seamounts have unique taxa (Alteromonadales, Nitrospira, and Magnetospiraceae) and a higher abundance of potential metal-cycling bacteria, such as Betaproteobacteriales and Pseudomonadales. The microbial beta-diversity from Atlantic seamounts was clearly grouped into microhabitats according to sediments, crusts, nodules, and geochemistry. Despite the time scale of million years for these deposits to grow, a combination of environmental settings played a significant role in shaping the microbiome of crusts and nodules. Our results suggest that microbes of Fe-Mn deposits are key in biogeochemical reactions in deep-sea ecosystems. These findings demonstrate the importance of microbial community analysis in environmental baseline studies for areas within the potential of deep-sea mining.

Seabed Classification Using Multibeam Echosounder Measurement Data

Multibeam Echosounder (MBES) utilizes acoustic waves emitted to the seafloor through a transmitter or transducer and records its reflective. The information obtained by MBES are depth data and the scattering value of the acoustic signal reflected by the object or the seabed, called backscatter. Acoustic backscatter can be used to classify objects or the seabed such as shipwrecks or seabed sediments. This study focuses on seabed classification using an acoustic backscatter obtained from the measurement at Alur Pelayaran Barat Surabaya (APBS). The data used in this research are acoustic backscatter from bathymetry data extraction and ground truth data of sediments. This study found the fine sand sediments with backscatter value −15.56 dB, and clayey silt sediments with backscatter value −24.36 dB. The correlations between backscatter and seabed sediments in study area were classified into four classes, clay class sediments with backscatter intensity range [(−33.81) – (−28)] dB, clayey silt class sediments with backscatter intensity range [(−27.99) – (−23)] dB, sandy silt backscatter intensity range [(−22.9) – (−18)] dB, and sand class sediments with backscatter intensity range [(−17.99) – (−10)] dB. Based on the results data are known in the study area of seabed conditions dominated by sediments type sandy silt.

The Importance of Storm Surge for Sediment Delivery to Microtidal Marshes

AbstractStorm surge has the potential to significantly increase suspended sediment flux to microtidal marshes. However, the overall effects of storm surge on microtidal marsh deposition have not been well quantified, with most modeling studies focusing on regular (astronomical) tidal flooding. Here we applied the Delft3D model to a microtidal bay‐marsh complex in Hog Bay, Virginia to quantify the contributions of storm surge to marsh deposition. We validated the model using spatially distributed hydrodynamic and suspended sediment data collected from the site and ran model simulations under different storm surge conditions with/without storm‐driven water level changes. Our results show that episodic storm surge events occurred 5% of the time at our study site, but contributed 40% of marsh deposition during 2009–2020. Our simulations illustrate that while wind‐driven waves control sediment resuspension on tidal flats, marsh deposition during storms was largely determined by tidal inundation associated with storm‐driven water levels. A moderate storm surge event can double sediment flux to most marshes around the bay and deliver more sediment to the marsh interior compared to simulations that include wind waves but not storm surge variations in water levels. Simulations of bay and marsh response to different storm surge events with varying magnitude of storm surge intensity reveal that total marsh deposition around the bay increased linearly with storm surge intensity, suggesting that future changes to storm magnitude and/or frequency would have significant implications for sediment supply to marshes at our study site.

Implication of multifractal analysis for quantitative evaluation of mineral resources in the Central Kunlun area, Xinjiang, China

Extensive research has been conducted to evaluate mineral resource potential based on geochemical data, but this work is still challenging due to the existence of multiple evaluation solutions based on different methods. In this paper, we combine the multifractal analysis method with typical multivariate statistical methods to analyse the spatial characteristics of geochemical stream sediment data, aiming to quantitatively study the ore-forming potential of the elements in the Central Kunlun area of Xinjiang, China. An R -type cluster analysis, Pearson correlation analysis, and principal component analysis are used to explore the correlations among the 12 target elements. The multifractal model is constructed using the method of moments to analyse the spatial distribution patterns of the elements, and corresponding multifractal parameters are extracted to quantitatively describe their ore-forming strengths in the study area. The results show that Co, V, Ti, Fe 2 O 3 , MgO and Cu compose a group of elements closely related to the regional geological background, while Pb, Zn, Bi, Sn, Au and Ba are potential metallogenic elements with relatively high ore-forming strengths and favourable ore-forming potential. Multifractal theory further validates and evaluates the favourable ore-forming element group obtained through conventional geochemical multivariate statistical methods, thus providing a new idea for small-scale geochemical prospecting. Thematic collection: This article is part of the Applications of Innovations in Geochemical Data Analysis collection available at: https://www.lyellcollection.org/cc/applications-of-innovations-in-geochemical-data-analysis

Sediment transport investigation in a karst aquifer hypothesizes controls on internal versus external sediment origin and saturation impact on hysteresis

Karst springs serve as major drinking water sources for the global population, yet there remains uncertainty regarding how contaminants like sediment are routed through karst. We find knowledge gaps pertaining to the processes that control the timing and magnitude of sediment delivery. To close these knowledge gaps, we: (1) collected high-frequency sediment and conductivity data from three surface streams and two cave sites in the inner bluegrass region of Kentucky, USA; (2) analyzed sediment hysteresis for 51 storm events over a two year period; (3) numerically modeled sediment transport through the aquifer; and (4) contextualized our results with a meta-analysis of ten karst springs in Europe and North America. Our results showed that 80% of storm events derived their sediment from external inputs through sinking streams while the remaining 20% were characterized by only internal resuspension of previously deposited cave sediment. We found that internal sediment transport was proportional to fluid shear stress in the cave and occurred exclusively during fully saturated aquifer conditions prior to the storm event. During partially-saturated aquifer conditions, externally sourced sediment pulses were efficiently routed to the spring irrespective of shear in the conduit network. Sediment hysteresis in surface streams was clockwise whereas the cave sites experienced counter-clockwise behavior. Clockwise and counter-clockwise hysteresis typically refer to proximal and distal sourcing for streams, but our findings suggest that this interpretation is not valid for subsurface karst settings. Hysteresis patterns for karst show dependence on the antecedent water conditions in the aquifer and internal versus external sourcing. meta-analysis results show that, despite high variability, counter-clockwise patterns of sediment hysteresis are very common for karst, which contrasts sediment hysteresis in surface streams. Results suggest that external sediment loading rather than internal resuspension is the most common control of sediment load at springs, which should inform management of karst groundwater resources.

Digital Outcrop Models applied to high-resolution stratigraphy in braided fluvial systems: A study case at Jaicós formation in Parnaíba Basin, NE Brazil

The visualization, analysis and interpretation of sedimentary data can be optimized with techniques such as the Digital Outcrop Models (DOMs) generated with the Structure from Motion – Multi-View Stereo (SfM-MVS) technique. In this paper, to demonstrate the usage of DOMs in the characterization of the depositional architecture of a braided fluvial system, we developed a case study in Jaicós Formation, Parnaíba Basin, NE Brazil, where a high-resolution stratigraphic analysis of a braided fluvial system was performed, and the potentials and limitations of the method were evaluated. This multi-scale reservoir analysis allowed the identification, description and interpretation of facies, bounding surfaces and architectural elements. In addition, it was also possible to predict quantitative attributes of the fluvial system that deposited this sequence and evaluate the potential of this formation as a reservoir.

Stable isotope profiles of soil organic carbon in forested and grassland landscapes in the Lake Alaotra basin (Madagascar): insights in past vegetation changes

Abstract. The extent to which the central highlands of Madagascar were once covered by forests is still a matter of debate: while reconstructing past environments is inherently difficult, the debate is further hampered by the fact that the evidence documenting land cover changes and their effects on carbon and sediment dynamics in Madagascar has hitherto mainly been derived from lake coring studies. Such studies provide an integrated view over relatively large areas but do not provide information on how land-use change affects hillslopes in terms of carbon and sediment dynamics. Such information would not only be complementary to lake inventories but may also help to correctly interpret lake sediment data. Carbon stable isotope ratios (δ13C) are particularly useful tracers to study the past dynamics of soil carbon over time spans ranging from years to millennia and thus to understand the consequences of land-use change over such time spans. We analysed soil profiles down to a depth of 2 m from pristine forests and grasslands in the Lake Alaotra region in central Madagascar. Along grassland hillslopes, soil organic carbon (SOC) content was low, from 0.4 % to 1.7 % in the top layer, and decreased rapidly to ca. 0.2 % below 100 cm depth. The current vegetation predominantly consists of C4 grasses (δ13C ∼ −13 ‰), yet topsoil δ13C-OC ranges between −23.0 ‰ and −15.8 ‰, and most profiles show a decrease in δ13C-OC with depth. This contrasts with our observations in the C3-dominated forest profiles, which show a typical profile whereby δ13C values increase slightly with depth. Moreover, the SOC stock of grasslands was ∼ 55.6 % lower than along the forested hillslopes for the upper 0–30 cm layer. δ13C values in grassland and forest profiles converge to similar values (within 2.0 ± 1.8 ‰) at depths below ∼ 80 cm, suggesting that the grasslands in the Lake Alaotra region have indeed developed on soils formerly covered by a tree vegetation dominated by C3 plants. We also observed that the percent of modern carbon (pMC) of the bulk OC in the top, middle and lower middle positions of grasslands was less than 85 % near the surface. This could reflect a combination of (i) the long residence time of forest OC in the soil, (ii) the slow replacement rate of grassland-derived OC (iii) and the substantial erosion of the top positions towards the valley position of grasslands. At the valley positions under grassland, the upper 80 cm contains higher amounts of recent grass-derived OC in comparison to the hillslope positions. This is likely to be related to the higher productivity of the grassland valleys (due to higher moisture and nutrient availability), and the deposition of OC that was eroded further upslope may also have contributed. The method we applied, which is based on the large difference in δ13C values between the two major photosynthetic pathways (C3 and C4) in (sub-)tropical terrestrial environments, provides a relatively straightforward approach to quantitatively determine changing vegetation cover, and we advocate for its broader application across Madagascar to better understand the island's vegetation history.

Altered nitrogen transformation pathways and a legacy of sediment organic matter enrichment

Estuaries are ecologically valuable ecosystems that process nutrients through complex biogeochemical processes. Here we identify drivers and inhibitors of nitrogen removal in unvegetated intertidal sandflats at six sites in Manukau Harbour (37° 2.00′S 174° 42.00′E) to quantify the exchange of solutes across the sediment-water interface, with nitrogen removal rates (NRR) measured at two contrasting sites (PI and CB) near and far, respectively, from an historical wastewater treatment plant. Solute fluxes were paired with sediment and macrofauna community data to identify drivers of ecosystem function. Fluxes of oxygen, nitrogen and phosphorous were found to vary among sites, with differences attributed to variation in sediment characteristics (grain size, chlorophyll a, organic content) and macrofauna community structure. Mean NRR was found to vary between sites (PI = 32.2 vs CB = 217.9 μmol N2/m2/h), with bioturbating macrofauna (bivalves Austrovenus stutchburyi and Macomona liliana), microphytobenthic biomass, and exposure to nutrients likely key contributing drivers.

Local Scour at Complex Bridge Piers in Bangladesh Rivers: Reflections from a Large Study

Many small-scale experimental, field, and empirical studies on bridge scour are available, however a large-scale study on local scour at a complex pier with wide variation in design parameters is still lacking. In this study, a country-wide assessment of local scour at complex piers of 239 bridges in Bangladesh is made. The hydrologic, hydraulic, and sediment data required in the assessment are obtained from secondary sources, primary measurements and samples, and numerical model simulations. An incredible number of 239 field visits are made, 1434 km of bathymetric surveys are carried out, and 478 samples of bed soils are collected and analyzed. The local scour depth is estimated using a complex pier configuration with pier, pile, and pile cap dimensions selected in consultation with structural and geotechnical engineers of bridge design. Flood frequency analysis and the HEC-RAS model simulation are used to estimate the hydrologic and hydrodynamic parameters needed in the assessment. A number of empirical formulations are used to estimate and compare the design local scours. The formulae of Melville and Coleman, Jain and Fischer, and Richardson are found to be dominant when deciding the design local scour depth at the bridge piers. Suggestions are provided to include a few additional equations in scour estimation and to develop a unified Bangladesh standard for scour depth estimation. The findings and recommendations of the study would be useful in planning and designing bridges in alluvial deltaic settings, particularly in the selection of empirical methods and mainstreaming of complex pier configuration in bridge scour assessment.

Natural Radioactivity and Metals in Pit Lakes in Sweden Analyzed by Principal Component and Cluster Analysis

The aim of this work was to determine which parameters are sufficient to measure in order to describe the water quality of a pit lake and to identify patterns in the data among different kind of pit lakes. The data consisted of ambient dose equivalent rate, elemental and radionuclide concentration, pH, and specific conductance in surface water and sediment samples collected from different types of mines. Data were tested for normality and log-normality and used in principal component analysis (PCA) and hierarchical cluster analysis (HCA). The normality tests indicated that only 40K was normally distributed, while only the 234,238U isotopes were log-normally distributed. HCA performed on parameters measured in surface water provided clusters that in most cases separated the elements according to their chemical groups. However, when HCA was performed on pit lakes, the clustering seemed to indicate that surface water might not be the preferred sample to differentiate between different types of pit lakes. PCA of surface water data resulted in three components that explained 72% of the variance when pH, SC, concentration of the elements Mg, K, Ca, Cu, Zn, Sr, Pb, activity concentration of 234,238U and 210Po, and ambient dose equivalent rate were included. For surface sediment data, the PCA resulted in three components explaining 83% of the variance when the concentration of Na, Mg, Al, P, K, Ca, Rb, Sr, Y, Tl, activity concentration of 234Th, 226Ra, 210Pb, 232Th (series average), and 40K, and ambient dose equivalent rate were included.

Evolution of Ocean Circulation in the North Atlantic Ocean During the Miocene: Impact of the Greenland Ice Sheet and the Eastern Tethys Seaway

AbstractThe Modern Ocean is characterized by the formation of deep‐water in the North Atlantic Ocean (i.e., NADW). This feature has been attributed to the modern geography, in which the Atlantic Ocean is a large basin extending from northern polar latitudes to the Southern Ocean, the latter enabling the connection of the otherwise isolated Atlantic with the Pacific and Indian Oceans. Sedimentary data date the establishment of the NADW between the beginning of the Eocene (∼49 Ma) and the beginning of the Miocene (∼23 Ma). The objective of this study is to quantify the impact of Miocene geography (∼20 Ma) on NADW using new simulations performed with the Earth System Model IPSL‐CM5A2. We specifically focus on the closure of the Eastern Tethys Seaway (ETS), dated between 22 and 14 Ma, which allowed the connection between the Atlantic and Indian Oceans, and on the Greenland Ice Sheet, whose earliest onset remains open to discussion but for which evidence suggest a possible existence as early as the Eocene. Our results show that the closure of the ETS does not appear to impact the establishment of NADW, because waters from the Indian Ocean do not reach the NADW formation zone when the seaway is open. Conversely, the existence of an ice sheet over Greenland strengthens the formation of NADW owing to topography induced changes in wind patterns over the North Atlantic, which in turn, results in a salinification of the North Atlantic and Nordic Seas, and in an increase in deep‐water formation.

Reviewing the Palaeoenvironmental Record to Better Understand Long-Term Human-Environment Interaction in Inner Asia During the Late Holocene

The Middle to Late Holocene spread of agropastoralism throughout Eurasia not only subjected domesticated taxa to stressors associated with novel environments but also induced changes in these environments following the introduction of these social-ecological systems. The mountainous region of Inner Asia comprises various steppe, meadow, and forest landscapes where zooarchaeological evidence suggests occupation by herding populations as early as 7,000 years Before Present (BP). Recent archaeobotanical findings indicate the introduction of cropping and the development of agropastoralism around 4,500 BP. Here, we review and synthesize palaeoenvironmental studies and data to examine anthropogenic impacts and modifications of these landscapes. From around 4,000 BP, we find significant changes in palynomorph, charcoal, sediment, and other proxy data, related to the introduction of agriculture to the region, with later intensifications in land use indicators at around 2,000 and 1,000 BP. We note that these impacts are not uniform or continuous through and across the records and may be evidence of shifting phases of occupation and landscape management. This temporal and spatial variability may also be a response to shifts in moisture availability due to long-term Holocene changes in the intensity of the summer monsoon and Westerly circulation systems. Changes in arboreal pollen indicate the development of intensified use of forest resources in the region, which we identify as a topic for future investigation. Based on these data, we stress the long-term human paleoecology in the study area and argue that traditional agropastoralist systems should be considered in future programs of landscape conservation in the region. This study also emphasizes the importance of future local scale multiproxy studies into past anthropogenic changes within the Inner Asian landscape.

Application of principal component analysis and a spectrum-area fractal model to identify geochemical anomalies associated with vanadium mineralization in northeastern Jiangxi Province, South China

The Jiujiang region in northeastern Jiangxi Province is known for hosting many black shale-type vanadium deposits, which are mainly found in the Cambrian Hetang Formation and Sinian Piyuancun Formation. In this paper, based on stream sediment data, principal component analysis (PCA) and spectrum–area (S–A) fractal modelling are used to identify geochemical anomalies associated with vanadium (V) mineralization. First, a dataset containing 957 samples of stream sediments with 39 elements was processed using correlation analysis and cluster analysis to find the closest V-related elements, and Ag and Cd were obtained. Secondly, the raster maps of V, Ag and Cd were created using multifractal inverse distance-weighted interpolation. PCA was then employed to combine the concentration values of V, Ag and Cd into a single variable representing the internal relationships among the three elements. Finally, S–A analysis was used to decompose the first component pattern obtained through PCA and to extract anomalies from the complex background. The results show that the known V deposits are located within highly anomalous areas, which are well corelated with the distribution of black shales of the Hetang and Piyuancun Formations. It is suggested that the northeastern part of Jiangxi Province potentially hosts undiscovered V deposits, and the identified anomalies could be further used to guide mineral exploration.Thematic collection:This article is part of the Applications of Innovations in Geochemical Data Analysis collection available at:https://www.lyellcollection.org/cc/applications-of-innovations-in-geochemical-data-analysis

Reconceptualising flood risk assessment by incorporating sediment supply

Sediments seriously increase flood risk. The lack of sediment data, as well as uncertainty in sediment yield and transport modeling, hampers the incorporation of sediment into flood risk assessment/early-warning systems. In this study, we targeted a 10 km reach that experienced a flash flood with high sediment inflows in 2019 and simulated sediment impacts on flood propagation and flood risk using a 1D hydraulic model. Two sediment inflow types were considered: sudden inflow from a debris flow and constant inflow from upstream. For the former type, different inflow times before, during and after the peak discharge were tested; for the latter type, different sediment concentrations and medium grain sizes were tested in the scenario design. Our results showed that when sediments inflowed into the reach in a short time, they greatly increased the water level by up to 3.7 m in the reach near the inflow point (i.e., 500–700 m upstream and downstream of the point). When sediments constantly inflowed from upstream, they influenced the water level of the whole reach but raised the water level by up to 1.2 m in the cross-sections, which showed strong bed aggradation. Sudden sediment inflow influenced the reach near the inflow point and might increase its flood risk to the highest level, whenever it occurred before, during or after the peak discharge. Constant sediment inflow did not affect the flood risk of the peak discharge much but increased the risk afterwards when the sediment concentration was higher than 40 kg m−3. Cross-sections showing increased flood risk were characterized by decreasing bed slopes or increasing widths. In view of the impacts of different sediment inflow types on flood risk, we developed a method to identify potential sediment risk. Together with current risk assessment by water flow, we proposed a framework to incorporate sediment into flood risk assessment.

Numerical Investigation of the Sediment Hyperpycnal Flow in the Yellow River Estuary

Sediment hyperpycnal flow is one of the most important processes for mass transport, which is essential to coastal morphodynamics. Herein, we studied the generation and maintenance of the sediment hyperpycnal flow in the Yellow River Estuary (YRE) using a three-dimensional finite volume coastal ocean model (FVCOM). The model considered the effect of sediment-laden water on density stratification, and was validated by field hydrodynamic and sediment data. Numerical results revealed that the hyperpycnal flow shows periodic characteristics with tidal cycles where the flow is weakened during flood tides and enhanced during ebb tides. A high suspended sediment concentration (SSC) of about 30–40 kg/m3 constitutes an important factor in the formation of hyperpycnal flows. High river discharge with high SSC is essential for maintaining the hyperpycnal flow in the YRE. The Simpson potential energy theory was applied to study the processes of estuarine circulation, tidal straining, and tidal stirring in the YRE. The tidal straining is the main control factor of the periodic stratification-mixing process of hyperpycnal flows in the YRE. Along the axis of the river mouth, the momentum balance is mainly dominated by the pressure gradient and advection.

Coastal protection system design at the Indonesian Mangrove Center in Pekalongan, Central Java – Indonesia

The Pekalongan area suffered from coastal flooding and heavy coastal erosion due to land subsidence and increasing wave condition in the last decade. Pekalongan government built a land dike in 2018 to protect Pekalongan city from coastal flooding. This study aims to determine a suitable coastal protection system, consisting of hard-structures and mangroves, to solve the erosion problem at the Pekalongan coast, specifically at the future Pekalongan Mangrove Information Centre (PIM). Environmental data, i.e., wind, wave, current, tidal, sediment, and soil data, were obtained by field survey and secondary data collection from open-source data. The selection of the most suitable coastal protection design concepts was performed by comparing several alternatives of structure materials. Coastal protection layout was obtained based on a numerical sediment transport model result using Delft3D software. From environmental data processing and analysis with various design aspects, the top elevation of the coastal protection structure is +4.5 m MSL (Mean Sea Level). The configuration of the mangrove planting media consists of ‘guludan’ structure technique with dimension 10 m x 5 m x 4 m.

The Analysis of Song Putri Reservoir Storage Area on Sedimentation Rate Using Mathematical Model Approach

Song Putri Reservoir is an artificial reservoir with the aim of irrigation channels for rice fields and flood control. This reservoir is located in Eromoko District, Wonogiri Regency Sedimentation modeling in the Song Putri reservoir is needed to analyze the amount of sediment deposition against the Song Putri Reservoir. To analyze the flow patterns and sediment distribution that occurs in reservoirs, SMS (Surface-water Modeling System) 8.0 Softwarse is used. This study aims to determine the flow patterns and effects of sediment distribution on reservoir changes. The data used include Song Putri Reservoir technical data, daily rainfall data for 10 years (2009-2018), sediment data, reservoir inflow data, and bathymetry maps. To analyze the magnitude of inflow and outflow of Song Putri Reservoir, hydrological analysis using empirical methods is used, while sedimentation modeling simulation uses SMS 8.0. Software based on the simulation, result the highest flow velocity in the 50 year return period is 0.097 m / s and the smallest is 0.00 m / s. Based on the simulation results of changes in the reservoirs base for 720 hours (1 month), the values ​​that in the return period of 50 years, 100 years and the highest 1000 years the highest was 5.795 m and the smallest of 0.001 m. Based on the calculation of prediction of sediment growth rates, it obtained the results of sediment growth rates with a percentage for a 50 year return period of 35.68% with a range of percentages between 19% - 21% and a percentage of 29.103% for a 100 year return period with a range of percentages between 22% - 24%, while the percentage growth rate of 1000 year return period sediments is 98 , 20% with a percentage range between 55% - 57%.

Mapping of favourable mining areas in the Tiouit area by multispectral remote sensing and airborne gamma-ray spectrometry coupled with geochemical data (Eastern Anti-Atlas, Morocco)

ABSTRACT The current investigation concern Tiouit region in order to perceive potential mining zones. Remote sensing data were the main component to process. In order to spot geochemical anomalies associated with the target zones, multispectral ASTER data, gamma-ray spectrometry, and stream sediment data were used. Crosta and SAM applications granted to map a spatial distribution of propylitic, phyllic, clay, and ferruginous alteration zones. The normalized ratios let the delineation of potassic alteration zones, including the Tiouit gold mine characterized by an intense alteration in the Ikniwn granodiorite. Thus, the potassic alteration zones are consistently co-located with the tectonic structures materialized by strong fracturing densities. The stream sediment geochemical investigation revealed that the cited areas have an important potential of mineralization, with high concentrations of As (136 g/t), Cu (91 g/t), Pb (141 g/t), Zn (392 g/t), Ag (3 g/t), Mo (11 g/t), Mn (0.2 g/t), and Fe (10.63 %).