Main Drainage System Research Articles

PRECIPITATION DATA FROM GOOGLE EARTH ENGINE (GEE) IN REVETMENT DRAINAGE EVALUATION IN KALIANDA

Floods can occur frequently if there are no organized and constant changes in land use. Flood issues in Waymuli, South Lampung, has been occurring due to changes in land use in the area. Prior studies regarding drainage of coastal revetments may have been done before. However, the analysis was done using precipitation data from GEE and therefore, new findings as the solution for the flood problems in the region were necessary. The main objective of this research is to assess the extent of success of drainage system management using rainfall information obtained via GEE. The method used was by evaluating the capability of the drainage system using data from GEE, which involve identifying and measuring the drainage capacity with the HEC-RAS application. This study conclude that the use of GEE can be accurately used to evaluate revetment drainage. Rainfall in the last two years were 54.0340 mm, 81.8905 mm in the last five years, and 104.0784 mm in the last ten years. However, GEE results show that the highest rainfall recorded in September 2022 was 46.857 mm. Based on the HEC-RAS evaluation, it was also found that the drainage system does not have the capacity to drain rain within a 2-year period. It can be concluded that the function of the drainage system in this area is to support the coastal revetment system, not as the main drainage system.

OS MINERAIS PESADOS E IDADES DE ZIRCÕES DOS SEDIMENTOS DE PRAIAS (BARRAS EM PONTAL) DOS RIOS PURUS E ACRE NO ESTADO DO ACRE (BRASIL)

The Purus River and its largest tributary, the Acre River, originate in Peru and constitute the main drainage system for the northeast and southeast portions of the State of Acre. These rivers and their smaller tributaries develop their beds over the Solimões Formation (Miocene to Pliocene-Late) and form a broad dendritic drainage pattern. During the rainy season, due to the high rainfall in the region and the low resistance of the drained rocks, these rivers mobilize a large volume of sediment, which is deposited mainly during the dry season, forming beaches (pointed bars), predominantly composed of fine sand, silt and clay. To investigate the probable primary sources of these sediments and their possible geographic locations, a mineralogical and morphological study of their heavy minerals and a geochronological analysis of their detrital zircons were used. Heavy minerals were extracted from fractions between 0.062-0.125 and 0.125-0.250. The transparent ones were investigated using a petrographic microscope and the opaque non-magnetic ones, together with the lithic fragments using a Scanning Electron Microscope (SEM/SED). In descending order, the main transparent heavy minerals of the Purus River are epidote (19%), kyanite (17%), zircon (14.5%), andalusite (8%), tourmaline (7.4%) and sillimanite (5 .5%), in addition to these, in amounts less than 5%, staurolite, garnet, apatite, amphibole, chlorite, muscovite, biotite, anatase, pyroxene and cassiterite occur. With similar content and different proportions, the assemblage of heavy minerals from the Acre River consists of andalusite (22.5%), kyanite (22.5%), zircon (12%), epidote (8%), sillimanite (5%) and tourmaline (5%), its accessories are: garnet muscovite, chlorite, apatite, amphibole, biotite, staurolite, titanite, anatase, serpentine and rutile. The non-magnetic opaque minerals of both rivers were shown to be predominantly formed by ilmenite, and the ages obtained in the zircons varied from 180 Ma to 3000 Ma, with great frequency in the intervals between 200-400 Ma and 900-1200 Ma.

Об обеспечении безопасной эксплуатации главной водоотливной установки рудника «Удачный»

Safety of the underground mining operations largely depends on the reliability of the functioning of the drainage facilities system. Practice shows that over the past few years, the reliability of the main drainage system of the underground kimberlite mine Udachny was noticeably decreased. One of the reasons for this was the low operational reliability of pumping equipment. External examinations of the failed parts of the flow part of pumps operating in the drainage systems of domestic kimberlite mines indicate the dominance of hydroabrasive wear in the overall picture of their multifactorial destruction. Mine waters pumped from the drainage mine workings of the Udachny mine is considered the most polluted among the mines of ALROSA. The main reason for the increase in the concentration of solid particles in the mine waters pumped to the daytime surface by the pumping equipment of the main drainage plant of the Udachny mine was the growing pollution of the waters coming from the drainage basins of the district drainage into its clarifying reservoirs. Such an intensive removal of mechanical impurities from the catchments of the district drainage into the clarifying tanks of the main drainage system is explained by an increase in the rate of siltation of the catchment tanks. And the rapid siltation of the catchments, in turn, is caused by the systematic removal of sludge-slurry pulp from the lower part of the skip trunk. It is established that the sludge slurry is formed during the overload of the extracted kimberlite ore from the feeder to the conveyor belt. There, its spilled part is washed off with water used for irrigation of diamond-bearing raw materials into the skip barrel. To reduce the rate of siltation of the drainage basins of the district drainage system, a mechanized complex for cleaning spilled rock mass was developed, described in the article.

Impact of Increased Water Inflow on Main Drainage System Efficiency in Mine

Impact of Increased Water Inflow on Main Drainage System Efficiency in Mine

Holocene ice-stream shutdown and drainage basin reconfiguration in northeast Greenland

Reliable knowledge of ice discharge dynamics for the Greenland ice sheet via its ice streams is essential if we are to understand its stability under future climate scenarios. Currently active ice streams in Greenland have been well mapped using remote-sensing data while past ice-stream paths in what are now deglaciated regions can be reconstructed from the landforms they left behind. However, little is known about possible former and now defunct ice streams in areas still covered by ice. Here we use radio-echo sounding data to decipher the regional ice-flow history of the northeastern Greenland ice sheet on the basis of its internal stratigraphy. By creating a three-dimensional reconstruction of time-equivalent horizons, we map folds deep below the surface that we then attribute to the deformation caused by now-extinct ice streams. We propose that locally this ancient ice-flow regime was much more focused and reached much farther inland than today’s and was deactivated when the main drainage system was reconfigured and relocated southwards. The insight that major ice streams in Greenland might start, shift or abruptly disappear will affect future approaches to understanding and modelling the response of Earth’s ice sheets to global warming.

Технологические решения по обеспечению надежной эксплуатации системы водоотведения на руднике «Удачный»

Drainage from the underground mines and coal mines is one of those technological processes, the degree of reliability of which, first of all depends on the continuity and safety of the mining of solid mineral deposits. In the process of pumping mine water to the surface, it is required to pay close attention to the operation of the water-drainage installation. Practice shows that at present the reliability of the functioning of the main water drainage system of the flooded kimberlite mine Udachny is quite low. The level of its reliability of functioning significantly decreased over the past 6 years. The main reasons for the transition to a lower level of operational safety of the drainage plant are the deterioration of the hydrogeological situation in the area of the kimberlite pipe being developed, as well as the operational reliability of pumping equipment of the drainage plant. It is dictated by the highwater content of the deposit, especially in the warm season, and the degree of contamination of the pumped mine waters with abrasive mechanical impurities. It is established that an increase of the water inflow in the warm season can lead to more intensive hydroabrasive wear of the pumping equipment parts. In order to limit the additional slip of surface water flows into the mine due to the planned dismantling of a local quarry drainage system, it is proposed to build two water catchments in the area of the non-working Udachny quarry, where the capacity of each is about 300 m3. Introduction of design clarification tanks № 5, 6 with a capacity of 3430 and 4030 m3, respectively, into the technological scheme of the main drainage of the Udachny mine will allow to reduce the average concentration of mechanical impurities in mine waters at the outlet of the water collectors from 17 to 4 g/l.

Analysis of Flood Control Effectiveness in Kali Sadar Regency and City of Mojokerto

Kali Sadar is part of the main drainage system in some areas of Mojokerto Regency and City. The main channel of Kali Sadar has a length of ± 23,211 Km with a drainage area of ± 614,92 Km². And has an upstream elevation of + 900 meters and an elevation of + 20 meters downstream from sea level. Flood control planning is carried out through river normalization analysis, slope reinforcement work planning, and embankment planning. All schemes are carried out so that the planned flood discharge is able to reach the ideal condition of the flood water level in the river. The study also reviewed through the planning of drainage facilities in the form of pump houses and retention ponds. In the results of the HEC-RAS analysis the results of the planned discharge used were a 25-year return period with a maximum discharge of 1080 m2/s. After simulating there is a cross section experiencing overtopping, to overcome overtopping, parape embankments are installed and with slope reinforcement work (revetment) on the slopes of the right and left sides of the river. The purpose of slope reinforcement is to accelerate the direction of river flow towards downstream so that there is no sediment erosion, by changing the manning value. However, after the flood control circuit, the cross section of the stream is only able to accommodate a maximum discharge capacity of 151.98 m2/s. For that, it is necessary to plan a pump house. Drainage facilities, in tackling the problem of excess runoff, pump houses are used in 5 locations with a plan of 80,000 m2 and a depth of 4.5 m. The plan uses 3 pump units with a capacity of 4.32 m2/s through an operating system of 4 inflow gates and 4 outflow gates which have a door width of 4.125 m and a height of 3.5 meters. pumps turn on when the water level is 0.08 m, 2 pumps will turn on when the water level is 0.30 m, and 3 pumps will turn on when the water level is 0.39 m.

Multi-proxy investigation of the post-evaporitic succession of the Piedmont Basin (Pollenzo section, NW Italy): A new piece in the Stage 3 puzzle of the Messinian Salinity Crisis

Paleoenvironmental reconstruction of the Mediterranean Basin at the end of the Messinian Salinity Crisis is contentious. One section that records this final phase (Stage 3) is the Pollenzo Section in the Piedmont Basin (NW Italy). Here, we present new stratigraphic, sedimentological, petrographic, micropaleontological (ostracods, calcareous nannofossils, foraminifera, dinoflagellates) and geochemical ( 87 Sr/ 86 Sr ratios) data from the Cassano Spinola Conglomerates (CSC) and interpret the paleoenvironment of this northernmost tip of the Mediterranean Basin. The CSC comprise three depositional units: members A and C, which were deposited subaqueously, and the intervening member B, which is continental. The CSC is topped by a ~ 50 cm-thick black layer, which is directly overlain by the open marine Argille Azzurre Formation of early Zanclean age. Our investigation reveals that member A is largely barren of autochtonous microfossils, except for an almost monospecific ostracod assemblage of Cyprideis torosa at the top, which indicates shallow-water (<30 m) conditions. Paratethyan ostracods and, possibly, taxa of calcareous nannofossils adapted to low-salinity water first occur in member C. 87 Sr/ 86 Sr ratios measured on ostracod valves from the member A/B transition (0.708871–0.708870) and member C (0.708834–0.708746) are lower than the coeval Messinian seawater values (~0.709024) and the 87 Sr/ 86 Sr ratios of a hypothetical lake filling Piedmont (>0.7090) estimated by means of the present-day 87 Sr/ 86 Sr signature of the Po river, the main drainage system of Northern Italy that receives the weathering products (including ions) of the Alps and Apennines. These values are likely to reflect the mixing of local high 87 Sr/ 86 Sr river water with low 87 Sr/ 86 Sr from the Mediterranean, which at the time was dominated by inputs from Eastern Paratethys, circum-Mediterranean rivers and Atlantic Ocean. Our results suggest that, at times during the final stage of the Messinian Salinity Crisis, the Piedmont Basin was hydrologically connected with the main Mediterranean Basin. At regional scale, this implies that the water level in the Mediterranean Basin was relatively high. • Piedmont Basin alternated subaqueous and continental conditions during MSC Stage 3. • 87 Sr/ 86 Sr values are inconsistent with subaqueous sedimentation in a local river-fed endorheic lake • Piedmont Basin-Mediterranean connection during times of Paratethyan ostracods spreading. • The Mediterranean water-level was occasionally relatively high during Stage 3.

PERENCANAAN SISTEM DRAINASE SMKN 1 KRAGILAN KABUPATEN SERANG

This research was conducted in a school area that has a conventional drainage system that is prone to flooding. To deal with flooding in the area, a new drainage system will be planned. The purpose of this study was to plan the main drainage system at SMKN 1 Kragilan, Serang Regency. The data or information used is primary data obtained from SMKN 1 Kragilan. The data processing method uses manual calculations according to the rational method for calculating rain discharge, and Manning's formula for channel discharge. After the calculation, the dimensions of the economic channel are obtained, because the channel can pass the maximum discharge for a certain wet, rough, and slope cross-sectional area. The main drainage channel is with a base width B = 0.77 m, water level h = 1 m and a height guard w = 0.50 m. The cross section of the channel is rectangular.

Groundwater Management in Ukraine: Trends, Directions of Development and Improvements

The article discusses certain aspects of groundwater management, in Ukraine, including. In particular, the theoretical foundations and applied aspects of groundwater management, as well as the main factors affecting the state of groundwater, are analyzed. The world experience of solving these problems is analyzed. Irrational and uncontrolled exploitation of groundwater determines many problems, including water scarcity and depletion of groundwater reserves due to their intensive extraction, environmental pollution, including solid waste (plastic, polyethylene, etc.) and toxic substances and pathogenic organisms. According to the results of the study, it is proposed to reduce the standard for mandatory reporting of water users, as well as to expand the coverage of the main water supply and drainage system to the maximum number of settlements in the shortest possible time, which will improve groundwater management in Ukraine. Keywords groundwater, aquifer, drainage and water supply, well, well, pump, sanitary standards, rent for water.

Assessment of flood risk reduction in DKI Jakarta: Cengkareng Sub-district

Due to geographical condition, Cengkareng is one of a well-known flood-prone area in West Jakarta, Indonesia Annual floods may occur due to the limited bank full capacity of the local drainage system. This flood causes a significant loss of both infrastructures and human life. One of the most significant efforts in reducing this flood risk is the improvement of Cengkareng Drain channel as the main drainage system in the area. Cengkareng Drain conveys the flow of Angke River and Mokervaart River into the Java Sea passing through Tangerang and Jakarta. This paper discusses about the contribution of several alternatives of improvement in reducing the related flood risk. The flood hazard is analysed based on the standard criteria of PUPR. The risk analysis is done in accordance to the BNPB guidebook. Based on this study, it is found that the drainage existing condition may cause a high flood risk level in 5 areas and an average risk level in 1 area. This flood risk could be reduced by applying both structural and non-structural mitigation efforts. It this case, it is found that structural mitigation of dike development combined with non-structural mitigation of local community capacity development is the most effective solution.

Significance of Uncinate Duct Dilatation in IPMNs: A New High-risk Criterion?

To evaluate the significance of UDD in IPMNs. The uncinate process of the pancreas has an independent ductal drainage system. International consensus guidelines of IPMNs still consider it as a branch-duct, even though it is the main drainage system for the uncinate process. A retrospective review of all surgically treated IPMNs at our institution after 2008 was performed. Preoperative radiological studies were reviewed by an abdominal radiologist who was blinded to the pathological results. In addition to the Fukuoka criteria, presence of UDD was recorded. Using multivariate analysis, the pathological significance of UDD in predicting advanced neoplasia [high grade dysplasia or invasive carcinoma (HGD/ IC)] was determined. Two hundred sixty patients were identified (mean age at diagnosis was 68 years and 49% were females): 122 (47%) had HGD/IC. UDD was noted in 59 (23%), of which 36 (61%) had HGD/IC (P < 0.003). On multivariate analysis, UDD was an independent predictor of HGD/IC (odds ratio = 2.99, P < 0.04). Subgroup analysis on patients with IPMNs confined to the dorsal portion of the gland (n = 161), also demonstrated UDD to be a significant predictor of HGD/IC in those remote lesions (odds ratio: 4.41, P = 0.039). This is the largest study to evaluate the significance of UDD in IPMNs and shows it to be a high-risk feature. This association persisted for remote IPMNs limited to the dorsal pancreas, suggesting UDD may be associated with an aggressive phenotype even in remote IPMN lesions.

Significance Of "Dominant" Uncinate Duct Dilatation In Ipmn: A New High-Risk Criterion

Presenter: Samer AlMasri MD | University of Pittsburgh Medical Center Background: The uncinate process of the pancreas has a dominant drainage ductal system that can either empty into the accessory or main pancreatic ducts. Although several autopsy series have outlined the anatomical footprints for this independent drainage system, current international consensus guidelines of intraductal papillary mucinous neoplasms (IPMNs) still consider it as a branch duct, even though it is the main drainage system for a once independent portion of the pancreas. We hypothesized that, in addition to the well-defined high-risk criteria of IPMNs, dilation of the “dominant” uncinate duct (UDD) is associated with advanced neoplasia (high grade dysplasia /invasive cancer = HGD/IC) on final resection pathology, and may therefore be classified as an independent high-risk criterion. Methods: A retrospective review of patients who underwent surgical resection of a pancreatic IPMNs between 2008-2019 at our institution was performed. Preoperative imaging studies (pancreas protocol CT and /or MRI) were reviewed by an abdominal radiologist who was blinded to the final pathological Results. In addition to the Fukuoka criteria, we recorded whether there was any UDD irrespective of the location of the primary lesion. Using multivariate logistic regression, the pathological significance of UDD was determined. Results: A total of 260 patients were identified. The mean age at diagnosis was 67.9 years and 49.2% were females. Of the entire cohort, 122 (47%) had HGD/IC and 138 (53%) had non-invasive (low/intermediate grade dysplasia) disease in the surgical specimen. UDD was noted in 59 (22.7%) patients, of which 36 (61%) had invasive disease on pathological evaluation (P < 0.003). On multivariate logistic regression for the entire cohort, adjusting for size, main duct dilation, presence of enhancing mural nodule, bilirubin level and demographics, UDD was an independent predictor of invasive disease (OR= 2.99, P < 0.04). Subgroup analysis was performed on patients with main/mixed duct IPMNs and branch duct IPMNs with high risk criteria confined to the dorsal pancreas (n=170, 66.4%) in order to determine the pathological significance of UDD in these remote lesions. Even in this subgroup of patients, UDD was a significant predictor of HGD/invasive cancer (OR= 7.6, P < 0.004), suggesting it may be associated with an aggressive field effect. Conclusion: This is the largest study to date evaluating the significance of uncinate “dominant” duct dilation in IPMNs, and shows it to be a high-risk feature associated with HGD/IC. This association persisted for IPMNs limited to the dorsal pancreas, suggesting UDD may be associated with an aggressive “field effect”. Although these findings warrant validation with larger prospective studies, we recommend this feature be considered an additional high-risk criterion in IPMN, irrespective of the location of the cystic lesion.

Biogeographical distribution of microbial communities along the Rajang River–South China Sea continuum

Abstract. The Rajang River is the main drainage system for central Sarawak in Malaysian Borneo and passes through peat domes through which peat-rich material is being fed into the system and eventually into the southern South China Sea. Microbial communities found within peat-rich systems are important biogeochemical cyclers in terms of methane and carbon dioxide sequestration. To address the critical lack of knowledge about microbial communities in tropical (peat-draining) rivers, this study represents the first seasonal assessment targeted at establishing a foundational understanding of the microbial communities of the Rajang River–South China Sea continuum. This was carried out utilising 16S rRNA gene amplicon sequencing via Illumina MiSeq in size-fractionated samples (0.2 and 3.0 µm GF/C filter membranes) covering different biogeographical features and sources from headwaters to coastal waters. The microbial communities found along the Rajang River exhibited taxa common to rivers (i.e. predominance of β-Proteobacteria) while estuarine and marine regions exhibited taxa that were common to the aforementioned regions as well (i.e. predominance of α− and γ-Proteobacteria). This is in agreement with studies from other rivers which observed similar changes along salinity gradients. In terms of particulate versus free-living bacteria, nonmetric multi-dimensional scaling (NMDS) results showed similarly distributed microbial communities with varying separation between seasons. Distinct patterns were observed based on linear models as a result of the changes in salinity along with variation of other biogeochemical parameters. Alpha diversity indices indicated that microbial communities were higher in diversity upstream compared to the marine and estuarine regions, whereas anthropogenic perturbations led to increased richness but less diversity. Despite the observed changes in bacterial community composition and diversity that occur along the continuum of the Rajang River to the sea, the PICRUSt predictions showed minor variations. The results provide essential context for future studies such as further analyses on the ecosystem response to anthropogenic land-use practices and probable development of biomarkers to improve the monitoring of water quality in this region.

Influence of Various Forms Voltage of the Pow-er Converter in the Complex of Fans of the Main Air Handling

Mining enterprises are examples of energy-intensive enterprises. At the same time, in the total volume of electric energy consumption, they consume about 80% such as: a crushing and sorting factory, a main drainage system, skip hoisting installations and main ventilation installations. In particular, ventilation plants consume approximately 30% of the total electricity consumption, this fact is due to the fact that according to the technology of underground mining, the iron ore mines are aired around the clock, and the electrical capacities of these plants reach 2 MW.Electromechanical complexes of fan installations, in turn, are equipped with synchronous drive electric motors. In order to regulate the performance of the main ventilation unit, inefficient measures are used: turning fan blades, and opening and turning working flaps. Meanwhile, with an increase in the depth of production of iron ore below 1500 m, the effectiveness of the existing ventilation process of underground workings is complicated, and these measures become even more ineffective.The process of the necessary improvement of ventilation systems in iron ore mines and the development of appropriate energy efficient systems to control the rotational speed of the synchronous drive motor of the main ventilation unit must be carried out in a plane of reach to reduce the electrical energy consumption of these units, in turn, will lead to the desired reduction of electrical energy consumption by iron ore mines at all. One of the real directions to achieve this goal is the creation of high-voltage converters, which will increase the energy efficiency of the electric drive of the main fan systems as a whole. In this study, based on the analysis, the possibility of using a power converter based on a multi-level cascade voltage inverter is considered. The proposed method of controlling and shaping the high-voltage supply voltage of the converter will increase the efficiency of the electromechanical system as a whole, as well as reduce the weight and volume of transistor modules and filter components, in the final form will achieve the desired level of performance of electromechanical complexes and all main fan systems as a whole.The prospect of introducing a controlled electric drive for main ventilation installations in underground mining enterprises is a priori economically viable measure that will significantly reduce power consumption by main ventilation systems, facilitate the start-up of synchronous motors and reduce starting currents. In addition, an adjustable electric drive increases the static efficiency and the range of technological use of the main ventilation systems, and, thereby, further reduces power consumption. Meanwhile, to achieve the desired level of electrical energy efficiency of electrical systems, as the entire complex of the main ventilation systems, it is necessary to develop sufficiently efficient circuits of voltage converters.Ref. 12, fig. 5, tabl. 2

Определение оптимальных показателей продуктивности агроэкосистем в условиях Ленкоранской низменности Азербайджана

The real and prognosticated dimensions of the farming lands productivity under natural agroecosystems in the Lankaran lowland condition have been defined. It was determined that the soil, climate, subsoil level and other factors of the landscape influence on the farming land productivity under the Lankaran Lowland condition. The productivity of cereals on these soils is 45.2 centner/ha, vegetables 318.2 centners per hectare, tea 81.2 centners per hectare, fruit 62.1 centner/ha. With the implementation of agroecological measures to increase the fertility of yellow–meadow soils, it is optimal to forecast cereals for 48.2 centners/hectare, 323.2 centner /ha for vegetables, 85.4 hectares for tea, and 66.2 centners per hectare for fruit. The lowest productivity in the hydromorphicallyholophytefacies groups of soil formation, in the soils of the given facies group, the productivity of wheat is 29.0...18.3 centner/ha, vegetables 214.3...99.1 centner / ha, natural fodder for air–dry weight of 19.2...4.1 c/ha. Soils related to the facies group of hydromoric-holophytic soil formation are characterized by low scores, which is explained with unfavorable conditions of formation on the one hand and high toxicity of readily soluble salts on the other hand. In order to reduce the concentration of salts along the soil profile on the territory of the research object, it is proposed to use agro-meliorative measures, taking into account the landscape parameters and the physico-chemical agro-meliorative and physico-mechanical properties of soils. In addition, in connection with the purpose of lowering the level of groundwater in the direction of the Caspian Sea, it is necessary to conduct a main drainage and collector system, on the basis of which the main part of the salts accumulated in the soil will be removed.

Improving Urban Drainage Systems Resiliency Against Unexpected Blockages: A Probabilistic Approach

Considering the increase of flood hazards in many large cities, the rehabilitation of hydro-urban infrastructures is an important concern for the municipal authorities. A probabilistic approach based on Monte Carlo Simulation (MCS) is presented in this study to improve the resiliency of urban drainage systems when they are subject to unexpected structural blockages. The approach is integrated with SWMM simulation model and an evolutionary search algorithm to find the best set of rehabilitation measures under a significant number of blockage scenarios. Experimental results on the west zone of main drainage system in Tehran city indicate that proposed approach outperforms the conventional hydraulic-based methodology in terms of cost effectiveness and functionality. Results also show that adding the redundancy to the system by bypass lines in bottlenecks is considerably more efficient for flood mitigation and the increase of system resiliency under blockage incidents rather than using conventional methods such as detention ponds and enlargement of the channel sizes.

Late Pleistocene - Holocene development of the Tista megafan (West Bengal, India): 10Be cosmogenic and IRSL age constraints

The Himalayan proximal foreland is characterized by Quaternary megafans, of which the formational mechanisms remain debated. The Tista megafan spreads over more than 16,000 km2 from the mountain front, where it is strongly incised, to the confluence of the Tista River with the Jamuna/Brahmaputra River, and stores sediments produced in the Sikkim Himalaya. We propose a scenario for the late Pleistocene - Holocene development of the Tista megafan based on new 10Be cosmogenic and Infra-Red Stimulated Luminescence (IRSL) age constraints, and discuss the main potential controls on its evolution. We suggest that two distal lobes developed successively downstream from a common proximal lobe. Deposition in the proximal lobe took place since at least ∼135 ka and incision began at 3.7−0.7+1.0 ka. The western distal lobe of the megafan was deposited early in the history of the megafan, when the Sikkim Himalaya catchment was drained by a tributary of the Ganga River, and was abandoned in the early Holocene (10–11 ka). The eastern, recent (<1 ka), and little incised lobe was built after the main Tista drainage system shifted eastward through nodal avulsions and can be considered still active. Approximately synchronous incision between terraces in the hinterland and megafan surfaces suggests that incision propagated rapidly through the system. Our data do not evidence a direct link between incicion and tectonic processes. Aggradation and incision episodes appear more compatible with a climatic control, through changes in monsoon intensity and associated sediment flux. Depositional episodes in the Tista megafan, as elsewhere in the Himalaya and its foreland, appear to correlate with periods of strong monsoon precipitation and associated high sediment flux toward the foreland. Abandonment and incision of megafan surfaces and hinterland terraces appear associated to both the onset and the ending of phases of strong monsoon precipitation, during which the balance between water and sediment discharge changes rapidly.

Simulation of the hydraulic performance of highway filter drains through laboratory models and stormwater management tools

Road drainage is one of the most relevant assets in transport infrastructure due to its inherent influence on traffic management and road safety. Highway filter drains (HFDs), also known as "French Drains", are the main drainage system currently in use in the UK, throughout 7000km of its strategic road network. Despite being a widespread technique across the whole country, little research has been completed on their design considerations and their subsequent impact on their hydraulic performance, representing a gap in the field. Laboratory experiments have been proven to be a reliable indicator for the simulation of the hydraulic performance of stormwater best management practices (BMPs). In addition to this, stormwater management tools (SMT) have been preferentially chosen as a design tool for BMPs by practitioners from all over the world. In this context, this research aims to investigate the hydraulic performance of HFDs by comparing the results from laboratory simulation and two widely used SMT such as the US EPA's stormwater management model (SWMM) and MicroDrainage®. Statistical analyses were applied to a series of rainfall scenarios simulated, showing a high level of accuracy between the results obtained in laboratory and using SMT as indicated by the high and low values of the Nash-Sutcliffe and R 2 coefficients and root-mean-square error (RMSE) reached, which validated the usefulness of SMT to determine the hydraulic performance of HFDs.

Determination of Watershed Boundaries in Turkey by GIS Based Hydrological River Basin Coding

A study was performed to develop hydrological river basin coding for Turkish river basins using the pfafstetter coding system. The coding system developed in this study is based on the combination of ECRINS and pfafstetter methods. River Basin District concepts were incorporated in this method so that it can be applicable to the management of Turkish River Basins. Developed hydrological river basin coding system is flexible, versatile and fits to all types of basins in Turkey. In order to show the efficiency of the coding system, it was applied to three river basins each of which has different hydrological and topographical features from the others. The basins used for the application of the coding system have complex features such as being transboundary basins, or being coastal basins whose discharge is not joining to the main drainage system, or being a closed basin discharging to an inland lake. Using the developed hydrological river basin coding defines river basin boundaries accurately, preventing conflicts in sectorial water allocation that are caused by uncertainty in the locations of water sources, producing a base for determining water potential and estimating extreme hydrological events of the basin, producing a basis for the prevention of water disputes among stakeholders within the basin, and helping implementation of Integrated Water Resources Management (IWRM) at basin level.