Overflow Water Research Articles

Future strengthening of the Nordic Seas overturning circulation

The overturning circulation in the Nordic Seas involves the transformation of warm Atlantic waters into cold, dense overflows. These overflow waters return to the North Atlantic and form the headwaters to the deep limb of the Atlantic meridional overturning circulation (AMOC). The Nordic Seas are thus a key component of the AMOC. However, little is known about the response of the overturning circulation in the Nordic Seas to future climate change. Here we show using global climate models that, in contrast to the North Atlantic, the simulated density-space overturning circulation in the Nordic Seas increases throughout most of the 21st century as a result of enhanced horizontal circulation and a strengthened zonal density gradient. The increased Nordic Seas overturning is furthermore manifested in the overturning circulation in the eastern subpolar North Atlantic. A strengthened Nordic Seas overturning circulation could therefore be a stabilizing factor in the future AMOC.

The Faroe‐Shetland Channel Jet: Structure, Variability, and Driving Mechanisms

AbstractThe Faroe‐Bank Channel (FBC) is a key gateway through which dense overflow water of the Nordic Seas supplies the lower limb of the Atlantic Meridional Overturning Circulation. Most recently, it was discovered that a deep jet through the Faroe‐Shetland Channel carries the bulk of this overflow water, but numerous questions regarding its structure, seasonality, and interannual variability as well as its linkage to atmospheric forcing remain poorly understood. A realistic high‐resolution ocean reanalysis (GLORYS12; 1993–2018) is, therefore, employed to address these questions. We first confirm that the Faroe‐Shetland Channel Jet is a permanent feature in GLORYS12 as well as in an ensemble of low‐resolution reanalyses. On seasonal time scales, we find a strong transport covariability between this deep jet and the observed FBC overflow. On interannual time scales, the strength of this deep jet is governed by the wind‐forced circulation in the Nordic Seas. Due to the largely barotropic structure of these flows, they have a signature detectable in satellite sea‐surface heights. Further, we suggest that the structure of the deep jet is qualitatively consistent with a geostrophic dynamical model that accounts for along‐isobath density variations. This study indicates that GLORYS12 is a promising product to study the dense water pathways and dynamics in the Nordic Seas.

Sampling-Dependent Transition Paths of Iceland–Scotland Overflow Water

Abstract In this note, we apply transition path theory (TPT) from Markov chains to shed light on the problem of Iceland–Scotland Overflow Water (ISOW) equatorward export. A recent analysis of observed trajectories of submerged floats demanded revision of the traditional abyssal circulation theory, which postulates that ISOW should steadily flow along a deep boundary current (DBC) around the subpolar North Atlantic prior to exiting it. The TPT analyses carried out here allow attention to be focused on the portions of flow from the origin of ISOW to the region where ISOW exits the subpolar North Atlantic and suggest that insufficient sampling may be biasing the aforementioned demand. The analyses, appropriately adapted to represent a continuous input of ISOW, are carried out on three time-homogeneous Markov chains modeling the ISOW flow. One is constructed using a high number of simulated trajectories homogeneously covering the flow domain. The other two use much fewer trajectories which heterogeneously cover the domain. The trajectories in the latter two chains are observed trajectories or simulated trajectories subsampled at the observed frequency. While the densely sampled chain supports a well-defined DBC, whether this is a peculiarity of the simulation considered or not, the more heterogeneously sampled chains do not, irrespective of the nature of the trajectories used, i.e., observed or simulated. Studying the sampling sensitivity of the Markov chains, we can give recommendations for enlarging the existing float dataset to improve the significance of conclusions about long-time-asymptotic aspects of the ISOW circulation.

Geospatial Analysis of Flood Occurrences in Selected Sub Wards of Morogoro Municipality - Tanzania

Flood is characterized by an overflow of water than drainage capacity of what is normally a dry land. Urban flooding has become progressively recurring and deadly natural disaster across different cities in the world. Floods results to a lot of damages which vary from place to place. Therefore, in curbing flood and its effects, it is important to have information on flood occurrences at different geographical scales. In this study, geospatial tools have been used to analyze the flood occurrences of selected sub wards in Morogoro Municipality, between 2016 and 2021. It was found that 41.84% of all houses in the selected 56 sub wards assessed in Morogoro Municipality had experienced flooding within the 5 years. Some sub wards faced high flood occurrence as much as 91.8% of all houses in such sub wards: Gohalema were flooded while others like Mzigila sub ward received a minimal 5.26% flooding occurrence. To further describe the spatial distribution, maps of flooding occurrence, their distribution, intensity and ranges had been generated. Furthermore, flooding simulation of the study area at different elevations was conducted to see what areas would or would not be flooded. To conclude, the study had shown that there was flood occurrences in Morogoro municipality between 2016 and 2021, and further shown that, there was spatial relationship between flood Occurrence and elevation as well as drainage network. However, further studies on the factors that affect flood occurrences in the study area are recommended.

A Review on Manhole Monitoring System

Abstract: Smart city is a concept which every country look forward to seed in their lands. To make that seed a big tree, a lot of aspects need to be addressed. Among them an important element is that, the drainage system. Even a small area with the proper drainage system will contribute a lot to the society. Manholes act as the access point to a sewer system. If there are any blockages in the drainage pipelines, manholes are the way to get into the underground pipes. If the blockages are not addressed, the sewage water overflow through the manholes which rises the temper of the pedestrians as well as vehicle drivers. Even tilted manhole covers are dangerous since they lead to accidents. Also the life of the scavengers who enters the manhole is not safe because of unawareness of the toxic level of the drainage or sewage water.

Interannual variability of red sea overflow water pathways in the Western Arabian Sea in an eddy rich reanalysis

The present study investigates the interannual variability of the advective pathways and transit times of the Red Sea Overflow Water (RSOW) in the western Arabian Sea using virtual particles as a proxy indicator for the poorly understood RSOW spreading. The Lagrangian simulations are based on the GLORYS12 eddy-rich reanalysis (1/12°), which assimilates most satellite and in situ observations from 1993 to 2018. Statistical analysis of particle positions reveals the Gulf's mouth is always the main RSOW export route out of the Gulf of Aden. Moreover, there is substantial interannual variability in the three RSOW pathways in the western Arabian Sea, which are consistent with in-situ salinity variability at the RSOW layer. The faster Socotra pathway is strongest for particles released in 1998–1999 and 2012 and almost non-existent for the ones released in 2006–2007. The strongest state of the Socotra pathway co-occurs with some of the most powerful El-Nino/Southern Oscillation and Indian Ocean Dipole events in history. A decadal seesaw stands out between the Northwest pathway, which advects RSOW northward offshore the Arabian Peninsula, and the Southwest pathway, which advects RSOW southward to the Somali Basin along the eastern side of Socotra. While the Northwest pathway strengthened from 1996 to 2011, the Southwest weakened. These changes are associated with interannual variability in the western boundary undercurrents and subsurface eddy kinetic energy. Interestingly, the Northwest pathway trajectories are eddy-dominated, in striking contrast with the Socotra and Southwest pathways, in which western boundary undercurrents are major players. This fact suggests that eddy-induced transport is likely to have a significant role in spreading the RSOW northward. No considerable interannual variability in transit times is detected for any pathway.

Improving Nickel Recovery in Froth Flotation by Purifying Concentrators Process Water Using Dissolved Air Flotation

The pressure for saving water by closing the water loops in mineral processing is increasing continuously. The drivers for higher recirculating rates include water scarcity in dry areas, environmental legislation that is becoming stricter in most countries, limitations set for wet tailings management and the increased demands for social licenses to operate. At the same time, to make mineral processing sustainable, the recovery of valuable minerals should be maximized. This leads for a need to close the process water circulation. To see the effect of closed water circulation on metallurgical performance, flotation tests were carried out with nickel concentrate thickener overflow water before and after the process of water purification by dissolved air flotation (DAF). Both total nickel recovery and concentrate grade in laboratory scale flotation tests to the Ni rougher-scavenger concentrate increased after DAF treatment. Chemical and mineralogical characterizations revealed that after DAF treatment, the process water contained fewer metal hydroxides and less fine-grained silicate mineral particles, which is most likely the reason for the improvement in the nickel flotation performance. Based on the feasibility study, improved nickel recovery by DAF treatment of process water can bring economic benefits at a concentrator plant.

Integrated Control of River Overflow Based on Microcontroller

This river overflow control is carried out in stages and in an integrated manner. The river water level is detected in real time with four levels, namely normal, alert, standby, and beware. The overflow of river water at each level will flow automatically through three floodgates that work simultaneously, followed by turning on three water pumps which also work simultaneously. The water flowing from the floodgates is channeled into an irrigation area, while the pumped water is flowed into a reservoir. This river overflow control is carried out in an integrated manner between monitoring the river water level, opening and closing the floodgates, working the pump, and detecting the reservoir maximum level. When all the floodgates are fully open and all pumps are running, and the water level in the reservoir has reached the maximum limit, the alarm will sound. Such conditions are stated in a state of over flow or out of control. This control is based on a microcontroller so that it has a fast response with minimal components. The control system is designed and made in a miniature form that runs well and with a fast response time.

Influence of Water Quality on Sulphide Ore Oxidation and Speciation of Sulphur Anions during Autogenous Milling

Earlier studies at the Kevitsa Cu-Ni concentrator plant have indicated that seasonal variations of the properties of the process water affect the oxidation of the surface of the minerals, and further, the pentlandite flotation performance. However, it is not clear whether the differences in flotation performance are solely due to changes in the mineral surface oxidation, and/or also due to surface oxidation-induced changes in the aqueous phase of the pulp. This paper investigates the effects of the mineral surface oxidation of Kevitsa Cu-Ni ore on the properties of the aqueous phase of the slurry. A systematic study was formulated to monitor the surface oxidation related changes in the mill circuit of the Kevitsa concentrator plant. The study was timed to coincide with a seasonally observed drop in the concentrator plant’s flotation performance, which happens during the summer months (June, July, and August). Both physicochemical parameters, as well as sulphur oxyanions in the plant process water, mill discharge, and hydrocyclone overflows were monitored. Also, the bubble size in selected rougher and cleaner cells was monitored. The results show that season-related changes in mineral surface oxidation cause clear differences in the aqueous phase chemistry of the mill circuit. The increased concentration of reduced sulphur species in the mill discharge is an indication of extensive oxidation of the ore during milling. Also, the bubble size of the flotation cells reacts to the observed seasonal change. The findings of the study confirm that the consequences expected, based on the theory of mineral surface oxidation, are observable downstream in the aqueous phase of the milling circuit. Based on these results, it is not yet possible to say whether the poor flotation performance is caused solely by the oxidation of the mineral surface or also by the properties of the aqueous phase of the slurry after milling. However, the results show that the plant needs both to find ways to limit oxidation rates in the summer, and to consider installing a more robust frother, capable of maintaining efficacy during the warm season. The findings of this study may help the plant to develop ways to enable a timely response to changes in the recycled process water quality, to prevent harmful impacts on pentlandite flotation. The former could be achieved by lowering the temperature of the process water and flotation air, whereas the latter could mean using a different frother.

Hydrochemical and Isotopic Evidence for Groundwater Conversion of Surface Water in Alpine Arid Areas: A Case Study of the Datong River Basin

Global warming and regional extreme climates will lead to unbalanced rainfall, melting glaciers, and permafrost degradation in alpine and arid mountain plains, thereby changing the regional hydrological cycle. The relationship between surface water and groundwater conversion is one of the important scientific issues of hydrological cycle climate response in alpine arid areas. Taking the Datong River Basin at the southern foot of the Qilian Mountains as the study area, based on 119 sets of basic hydrochemical parameters and deuterium-oxygen isotope data, using multivariate statistical analysis and isotopic techniques, the hydrochemical characteristics of surface water and groundwater in the basin and their mutual transformation process were studied. The results showed that the surface water was HCO3-Mg·Ca type, which was mainly controlled by rock weathering, whereas the groundwater was HCO3-Mg·Ca type and Cl·SO4-Na type, which was controlled by rock weathering and evaporation concentration. There was a small amount of calcium and magnesium feldspar dissolved in the upstream groundwater, and the chemical components of the midstream groundwater were mainly the weathering and dissolution of carbonate rocks. The contribution rates of weathering filtration, anthropogenic activities, native sedimentary environment, alternating adsorption of cations, and other factors to the chemical components of surface water and groundwater in the study area were 39.1%, 15.0%, 12.6%, 13.8%, and 19.5%, respectively. The deuterium and oxygen isotope contents of Datong River water showed a trend of enrichment to depletion along the groundwater flow direction. The δD and δ18O isotope test results showed that the deuterium and oxygen isotope content in the Datong River along the groundwater flow showed a trend of enrichment to depletion. The upper and middle reaches of the Datong River were mainly recharged by atmospheric precipitation, whereas the lower reaches were affected by geological structure and influenced by hydrogeological conditions, which was mainly due to diving and spring water overflow to supply river water, as the discharge area of groundwater.

Simulasi Banjir Sungai Putri Danau Sipin Kota Jambi

River is one of the water resources that is widely used to meet raw water needs. Along with changing conditions in the river basin, changes in land use and population growth make the river not function optimally as it should. One of the natural phenomena that threatens the existence of human life in several regions in Indonesia every time the rainy season enters it is sure to experience flooding, especially in the Jambi city area. This is due to the reduced capacity of the drainage cross-section so that with high rainfall it is no longer able to accommodate flood discharges resulting in overflow of water. The purpose of this study is to determine the difference between the Sungai Putri flood discharge and Q25 and identify flood points and provide solutions to flood problems that occur in the river / or in the Sungai Putri Lake Sipin drainage, Jambi city. In this study, secondary data used for 10 years of rainfall and cross-sectional data of Putri River drainage. The results of the calculation of the planned flood discharge using the rational mononobe method Q2 = 18,695 m3/s, Q5 = 23,171 m3/s, Q10 = 26,397 m3/s, Q20 = 30,021 m3/s and Q25 = 30,804 m3/s. And the next step using the HAC-RAS 3.13 software. After being analyzed using software, the drainage point that cannot accommodate the incoming flow, it is necessary to redesign the Putri River so that it can accommodate the water capacity that occurs every year due to high rainfall.

Lagrangian Overturning Pathways in the Eastern Subpolar North Atlantic

Abstract The strength of the Atlantic meridional overturning circulation (AMOC) at subpolar latitudes is dominated by water mass transformation in the eastern subpolar North Atlantic Ocean (SPNA). However, the distribution of this overturning across the individual circulation pathways of both the Subpolar Gyre (SPG) and the Nordic seas overflows remains poorly understood. Here, we introduce a novel Lagrangian measure of the density-space overturning to quantify the principal pathways of the time-mean overturning circulation within an eddy-permitting ocean model hindcast. By tracing the trajectories of water parcels initialized from the northward inflows across the Overturning in the Subpolar North Atlantic Program (OSNAP) East section, we show that water mass transformation along the pathways of the eastern SPG accounts for 55% of the mean strength of the eastern subpolar AMOC. Water parcels following the dominant SPG pathway, sourced from the Subarctic Front, form upper North Atlantic Deep Water by circulating horizontally across sloping isopycnals in less than 2 years. A slower SPG route, entrained by overflow waters south of the Iceland–Faroes Ridge, is a crucial conduit for subtropical-origin water masses to penetrate the deep ocean on subdecadal time scales. On reproducing our findings using time-averaged velocity and hydrographic fields, we further show that the Nordic seas overflow pathways integrate multiple decades of water mass transformation before returning across the Greenland–Scotland Ridge. We propose that the strong disparity between the overturning time scales of the SPG (interannual) and the Nordic seas overflows (multidecadal) has important implications for the propagation of density anomalies within the eastern SPNA and hence the sources of AMOC variability.

Formation and pathways of dense water in the Nordic Seas based on a regional inversion

Dense waters formed in the Nordic Seas spill across gaps in the Greenland-Scotland Ridge into the abyss of the North Atlantic to feed the lower limb of the Atlantic Meridional Overturning Circulation. The overflow water transport is well known, but open questions remain regarding where and how the dense overflow waters are formed and transported to the ridge. Here we develop a regional high-resolution version of an inverse method called Total Matrix Intercomparison, which combines hydrographic and geochemical tracer observations between 2000 and 2019 to resolve the pathways that connect the overflows to their origins. Consistent with previous studies we find two main pathways feeding the Denmark Strait Overflow Water (DSOW): the East Greenland Current and the North Icelandic Jet. Most of the water supplied by the North Icelandic Jet originates in the Greenland Sea (82 ± 2%) and flows southward along an outer core of the East Greenland Current, as well as along a previously unknown pathway crossing the Jan Mayen Ridge into the Iceland Sea. In total, 39 ± 2% of the DSOW originates in the Greenland Sea, while the Iceland Sea and the Atlantic Domain of the Nordic Seas account for 20 ± 3% and 19 ± 2%, respectively. The majority of the Faroe Bank Channel Overflow Water originates in the Greenland Sea (46 ± 8%) and the Arctic Ocean (25 ± 9%). These dense waters approach the sill in the Iceland-Faroe Slope Jet and along the eastern side of the Jan Mayen Ridge. The inversion reveals unprecedented details on the upstream sources and pathways of the overflows, which have not previously been obtained using observations.

Numerical investigation of airfoil ice accumulation: Ice shape and ice crack propagation

For aircraft ice accumulation, this paper analyzed airfoil icing with OpenFOAM software, including the ice shape analysis, ice crack propagation analysis and ice stress intensity analysis. The direction of water overflow is divided along the chordwise and spanwise of the airfoil. And the heat and mass transfer process of icing is investigated by modifying the classical Messinger icing thermodynamic model. Based on the traditional calculation method of 2D surface heat transfer coefficient, an improved 3D airfoil surface heat transfer coefficient calculation method is proposed. And ice accretion is along the direction normal to the surface. The model of airfoil ice shape and crack growth was established by the self-developed C-DEICE program. The flow field of the 2D and 3D ice shape obtained by reverse modeling were calculated by the C-DEICE program. The crack propagation and ice shedding shape were simulated in 2D and 3D. Icing completely changes the pressure distribution on the airfoil surface, and the aerodynamic performance is decreased by 91.6%. The displacement of ice body above the crack increases significantly with the crack propagation, and the displacement increases with the distance from the crack tip, which is consistent with the 2D crack propagation simulation results. Furthermore, the self-developed C-DEICE program can better capture the trend of ice shape and the range of ice covering on the airfoil surface. It is found that the fluid–solid coupling method is reliable for determining the initial crack location. Meanwhile, it also lays a theoretical foundation for the follow-up study of ice shedding trajectory.

No changes in overall AMOC strength in interglacial PMIP4 time slices

Abstract. The Atlantic Meridional Overturning Circulation (AMOC) is a key mechanism of poleward heat transport and an important part of the global climate system. How it responded to past changes in forcing, such as those experienced during Quaternary interglacials, is an intriguing and open question. Previous modelling studies suggest an enhanced AMOC in the mid-Holocene compared to the preindustrial period. In earlier simulations from the Palaeoclimate Modelling Intercomparison Project (PMIP), this arose from feedbacks between sea ice and AMOC changes, which were dependent on resolution. Here we present an initial analysis of recently available PMIP4 simulations for three experiments representing different interglacial conditions – one 127 000 years ago within the Last Interglacial (127 ka, called lig127k), one in the middle of the Holocene (midHolocene, 6 ka), and a preindustrial control simulation (piControl, 1850 CE). Both lig127k and midHolocene have altered orbital configurations compared to piControl. The ensemble mean of the PMIP4 models shows the strength of the AMOC does not markedly change between the midHolocene and piControl experiments or between the lig127k and piControl experiments. Therefore, it appears orbital forcing itself does not alter the overall AMOC. We further investigate the coherency of the forced response in AMOC across the two interglacials, along with the strength of the signal, using eight PMIP4 models which performed both interglacial experiments. Only two models show a stronger change with the stronger forcing, but those models disagree on the direction of the change. We propose that the strong signals in these two models are caused by a combination of forcing and the internal variability. After investigating the AMOC changes in the interglacials, we further explored the impact of AMOC on the climate system, especially on the changes in the simulated surface temperature and precipitation. After identifying the AMOC's fingerprint on the surface temperature and rainfall, we demonstrate that only a small percentage of the simulated surface climate changes could be attributed to the AMOC. Proxy records of sedimentary Pa/Th ratio during the two interglacial periods both show a similar AMOC strength compared to the preindustrial, which fits nicely with the simulated results. Although the overall AMOC strength shows minimal changes, future work is required to explore whether this occurs through compensating variations in the different components of AMOC (such as Iceland–Scotland overflow water). This line of evidence cautions against interpreting reconstructions of past interglacial climate as being driven by AMOC, outside of abrupt events.

Optimasi Sistem Tata Air pada Daerah Irigasi Rawa (Food Estate) Dadahup Kabupaten Kapuas Provinsi Kalimantan Tengah

The Swamp Irrigation Area (DIR) of Dadahup District is a former Peat Land Development (PLG) with an area of around 21,226 Ha. The water management system at DIR Dadahup utilizes changes in sea tides as a source of water to the land and drainage to drain water out of the land. However, in its implementation, DIR Dadahup experienced several problems such as flooding during the rainy season and experiencing drought during the dry season. These conditions indicate the need for land management and water management systems to overcome existing problems. The purpose of this study was to optimize the water management system for irrigation by optimizing the functions and benefits of swamp land in Dadahup, Kapuas Regency, Central Kalimantan Province. Optimization of the water system is carried out by modeling using the HEC-RAS program. Flow modeling with HEC-RAS in irrigation canals can be simulated into two scenarios, namely scenarios using gates and scenarios with doors and pumps for the rainy and dry seasons. Based on the results of the modeling analysis that has been carried out, the surface elevation during the dry season is in the range of +0.06 ms/d + 0.77 m, which is below the average land elevation (+0.8 m MSL). experience drought because the water in the canals cannot irrigate the land. The water level during the rainy season is in the range of +0.82 ms/d +1.53 m, which is above the average land elevation. It can be concluded that irrigation canals cannot accommodate the overflow of water that occurs at the planned discharge so that the land is flooded. The scenario model is suitable for the Dadahup DIR land use, namely with the door and pump scenario, the water level elevation for the dry season and the rainy season can reach the target of +1.0 m, then the water level elevation for the rainy season can also reach the target of +0, 7m.

“Finnish”-Saami Flood in the Toponymy of Karelia and Russian North

The article analyzes four toponymic stems with the meaning of ‘flood, overflow of water’ that have Balto-Fennic and — more broadly — Finno-Ugric origins and are attested in the toponymy of Karelia, as well as beyond its southeastern borders — in the Russian North. The materials were retrieved from of the Card index of toponyms of Karelia and adjacent regions, as well as the Toponymic card index of the Ural University (data related to Russian North). By virtue of semantics, the toponymic stems under consideration primarily occur in the names of water bodies, as well as flood lands. The analysis shows that all stems have verbal nature and thus are deverbal names. For two of them (Tulv- and Pais-/Paiž-) etymons (tulva, paise) are found in modern Balto-Fennic languages. For the third stem — Kost- (Kosht-, Kust-, Kusht-), which is traditionally associated with Balto-Fennic adjective kostea ‘wet,’ the author suggests the possibility of a ‘flood’-related interpretation. This proceeds, on the one hand, from the fact that the waterlogged places during the flood can be characterized as damp, wet, on the other hand, from the meaning of return movement inherent in the verbal stem kosta-. The latter reflects the characteristic movement of water back and forth. Finally, the fourth toponymic stem is based on the Saami linguistic data and their proto-linguistic reconstruction *pēnte- ‘overflow, rise (about the water level)’ which is presumably present in a number of place names. The analysis makes it possible to revise or at least offer new possibilities for the etymological interpretation of some landscape terms (e.g. pendus), as well as toponymic stems that are substratal for the Russian North and toponyms formed from them (Kushta, Pazha, Pindusha). It ultimately advances us in our search for the origins of the substrate toponymy of the Russian North.

Horizontal distribution of chlorophyll-a and water quality on Delta Wulan Estuary, Demak Regency, Central Java, Indonesia

The overflow of water from the Wulan River has an impact on the amount of nutrients and pollutants that enter the Delta Wulan Estuary. Abundant nutrient content greatly affects the level of primary productivity, especially chlorophyll-a content. The study aimed to determine the horizontal distribution of chlorophyll-a and water quality in the Delta Wulan estuary waters. Sampling was carried out in June 2023 at 12 stations on Delta Wulan Estuary. Demak Regency. Based on the analysis results, the highest chlorophyll-a content was found at station 12 (10.59 - 12.20 mg/l). The nitrate content was found at station twelve (9.2 - 10.0 mg/l), and the highest value of phosphate content was found at stations 10 and 12, with a range of 0.22 - 0.25 mg/l. The range of sea surface temperatures ranges from 29.3–33.2°C. The salinity content value has ranged from 30.0 – 32.0 ppt. It can be concluded that water quality data can support the content of chlorophyll-a in the waters of the Wulan Delta Estuary.

Flood Inundation Simulation Using HEC-GeoRAS with Hydro-Enforced-DTM LiDAR Data

Flood is one of the disasters that often occurs in Indonesia, especially in Flood is one of the disasters that often occur in Indonesia, especially in Kebumen-Kutoarjo. One method to calculate flooding from river overflow is DTM data. One known method is hydro enforcement or often referred to as hydro-enforced-DTM. DTM data are used for various applications in simulating flood forecasts from river overflows. In this study, a flood evaluation simulation was carried out as a preparation step for flood disaster mitigation to determine the estimated area that might be affected by flooding. Hydro enforced—used in making simulations of flood inundation from river overflow. The simulation results show the estimation of the overflow of river water that begins to exceed the river bank and extensive inundation extension results do not show actual results because producing a partial visualization that is not flooded. The simulation results indicate that there is no overflow River water. After validating the parameters of the results due to the flood on January 2019, obtained visualization results: do not show the occurrence of inundation in rice fields is about 7.86 hectares and not inundated residential areas and roads Kebumen-Kutoarjo transportation. Furthermore, the results will be able to simulate flood estimates from river overflows. The simulation results show estimates that are starting to exceed the riverbanks with a discharge of 225 m3/s. While the simulation results with an actual discharge value of 95.77 m3/s do not depend on rice fields and residential areas.

Применение спектральных водных индексов на хвостовом хозяйстве Дарасунского рудника по данным дистанционного зондирования Земли программы Landsat

At present, the problem of ensuring the environmental safety of tailings dumps and dams holding them is acute in the mining cluster not only in Russia, but also in the world. Stale tailings located in a hydraulic structure are man-made deposits and are considered as an object of development in the future. Therefore, the formation of a database of the areas of the water mirror of the basins of the cascade of tailings for a long period of operation is an urgent scientific problem. It is important to analyze and predict potential threats to the city-forming mining enterprise and nearby territories. This problem can be solved by using geoinformation systems and multispectral data. The object of the research is a complex of tailings dumps’ cascades of the Darasunsky mine. The goal is to provide spatio-temporal assessment of the areas of the water mirror of the basins of the tailings dumps’ cascade of the Darasunsky mine for the period from 1997 to 2022 in order to predict environmental safety. The research objectives are the following: assessment of the environmental situation at the Darasunsky mine; selection of the optimal method for decoding the water surface; collection and formation of an archive of remote sensing data; calculation of spectral indices and retrospective analysis of changes in the water surface area of the tailings of the Darasunsky mine; forecast of emergency situations of lithospheric, hydrospheric, airborne, biological pollution. A spatio-temporal assessment of the areas of the water mirror of the basins of the tailing dumps’ cascade has been made to assess the use intensity of these structures with the construction of graphs of changes in the areas of the water surface over a 25-year period. Thanks to the division of the tailings storage into cascades, it has become possible to locally determine the filling of 4 tailings sections with tailings pulp. The data obtained allow monitoring for the rational use, conservation, stopping the operation of hydraulic structures (in particular tailings dumps), their impact on the environment. The use of spectral water indices according to the remote sensing data of the Landsat program will allow predicting and preventing emergency situations at the tailings dump, which has been in operation for many decades, to prevent the overflow of water over the crest and body of the enclosing dams.