scholarly journals Determination of the length of Bogowonto double jetty as the river mouth stabilization

2021 ◽  
Vol 930 (1) ◽  
pp. 012027
Author(s):  
T E Bhakty ◽  
A H Swasono ◽  
N Yuwono ◽  
A F Ghalizhan ◽  
T Widyasari
Keyword(s):  
Coastal Area ◽  
River Discharge ◽  
River Flow ◽  
River Mouth ◽  
Tidal Range ◽  
Wet Season ◽  
Flow Through ◽  
The One ◽  
River Mouths

Abstract One of the problems around estuaries with the wave-dominated combination of a small tidal range and low river discharges in the dry season was the mouth closed by a sand barrier. Longshore sediment flows silted up the river mouth while river flows were insufficiently large for flushing sand barriers. When the wet season started, river discharge suddenly enlarged. Discharge can’t flow through the river mouth due to being hindered by the sand barrier. The consequence was that the hinterlands were inundated. Yogyakarta International Airport (YIA) is located in a coastal area of Kulon Progo regency, between two river mouths (Bogowonto river and Serang River). The two rivers have unstable river mouths. The double Jetty had been built at the Bogowonto river, but its condition was damaged. Meanwhile, the breakwater was constructed at the river mouth Serang and called Tanjung Adikarto. Double Jetties will be built to stabilize the Bogowonto river mouth. The purpose of this paper is to provide an overview of the length of the Jetty to be more effective in stabilizing the Bogowonto river mouth. Therefore, so that more easily opened by river flow and does not cause excessive erosion on the one side of the Jetty.

scholarly journals Propagation of tides along a river with a sloping bed

2019 ◽  
Vol 872 ◽  
pp. 39-73 ◽  
Author(s):  
K. Kästner ◽  
A. J. F. Hoitink ◽  
P. J. J. F. Torfs ◽  
E. Deleersnijder ◽  
N. S. Ningsih
Keyword(s):  
Sea Level ◽  
River Discharge ◽  
River Flow ◽  
River Mouth ◽  
Tidal River ◽  
Tidal Range ◽  
Narrow Channels ◽  
Tidal Waves ◽  
Frictional Damping ◽  
Set Up

Conceptually, tidal rivers are seen as narrow channels along which the cross-section geometry remains constant and the bed is horizontal. As tidal waves propagate along such a channel, they decrease exponentially in height. The more rapid the decrease, the stronger the river flow. Near the coast, the tidally averaged width and depth change little throughout the year, even if the river discharge varies strongly between the seasons. However, further upstream, the water depth varies considerably with the river discharge. Recent observations from the Kapuas River, Indonesia, show that the water surface forms a backwater profile when the river flow is low. In this case, the depth converges, i.e. it gradually decreases between the river mouth and the point where the bed reaches sea level. This effect distinctly influences how tidal waves propagate up river so that their wave height does not decrease exponentially any more. We present a theoretical analysis of this phenomenon, which reveals several so far overlooked aspects of river tides. These aspects are particularly relevant to low river flow. Along the downstream part of the tidal river, depth convergence counteracts frictional damping so that the tidal range is higher than expected. Along the upstream parts of the tidal river, the low depth increases the damping so that the tide more rapidly attenuates. The point where the bed reaches sea level effectively limits the tidal intrusion, which carries over to the overtide and the subtidal water level set-up.

Determination Of The Optimal Guide Curve For A Reservoir, Case Study Copa Dam, Boyacá

2020 ◽  
Author(s):  
Felipe Sierra ◽  
Jorge Sanabria ◽  
Gerald Corzo ◽  
Germán Santos
Keyword(s):  
Hydrological Model ◽  
Irrigation District ◽  
Maximum Rainfall ◽  
Annual Series ◽  
Continuous Simulation ◽  
Hydrological System ◽  
Flow Through ◽  
The One

<p>Reservoir operation has been a task that always relate to integrated water resources concepts, the rules of such systems require to adapt to changes in the uses of water or in their prioritization. The storage body of La Copa reservoir, located in the upper Chicamocha river basin in Colombia was originally built with the objective of mitigating the floods over the upper Chicamocha valley. However, an irrigation district was latter established, with the objective of supplying water to farmers. This study presents the analysis and optimization of operational rules to minimize the likelihood of floods and shortages for the irrigation district. This is done by contemplating the uncertainty in the hydrological system.</p><p>A methodology is developed to obtain the optimal management and operation of the reservoir, aiming at reducing droughts and flood, which will end up in a regulated basins. A simulation model of the reservoir using the HEC-ResSim tool was used to aim at an optimal guide curve. The guide curve in this study is the base for operational decisions. A continuous simulation hydrological model using the HEC-HMS tool. The model was calibrated using annual series of daily flows as input into the reservoir model.  A two-dimensional hydrodynamic model using (HEC-RAS 2D) was used to test the results of regulation through the comparison of the simulations of the current and optimal regulation conditions.  Several guide curves were developed for the evaluation of the operation. Four of them among are selected and tested using the HEC-ResSim model through the quantification of the minimum and maximum volumes discharge failures. Finally, the guide curve with the least number of failures was selected as the one that provides the best system operation. The benefits of the selected guide curve were verified by the transit of the regulated hydrographs in the 2D hydraulic model. The simulation was carried out in the most period in terms of flows and maximum rainfall, from April 06 to May 15, 2011. The period between April 15 and 21 has the highest flow through the critical sector. On the other hand, unregulated conditions were evaluated using the flows of the hydrological model. It is found that the channel presents a notable improvement, in the simulation of April 15, through the discharges made in a controlled manner from the La Copa reservoir. The methodology presents a simple and practical way to obtain relative optimal operational rules for a multipurpose storage.</p>

scholarly journals Spatial linkages between coral proxies of terrestrial runoff across a large embayment in Madagascar

2012 ◽  
Vol 9 (8) ◽  
pp. 3063-3081 ◽  
Author(s):  
C. A. Grove ◽  
J. Zinke ◽  
T. Scheufen ◽  
J. Maina ◽  
E. Epping ◽  
...  
Keyword(s):  
River Discharge ◽  
River Flow ◽  
Sediment Runoff ◽  
Site Specific ◽  
Terrestrial Runoff ◽  
Physiochemical Parameters ◽  
Spatial Differences ◽  
Vital Effects ◽  
Spatial Linkages ◽  
River Mouths

Abstract. Coral cores provide vital climate reconstructions for site-specific temporal variability in river flow and sediment load. Yet, their ability to record spatial differences across multiple catchments is relatively unknown. Here, we investigate spatial linkages between four coral proxies of terrestrial runoff and their relationships between sites. Coral cores were drilled in and around Antongil Bay, the largest bay in Madagascar, and individually analysed for fifteen years of continuous luminescence (G / B), Ba / Ca, δ18Osw and δ13C data. Each coral core was drilled close to individual river mouths (≥ 7 km), and proxy data were compared to modelled river discharge and sediment runoff data for the three corresponding catchments. A reasonable agreement between terrestrial runoff proxies with modelled river discharge and sediment yield was observed. Some inconsistencies between proxy and modelled data are likely linked to proxy behaviour, watershed size and local environmental physiochemical parameters. In general, the further a coral resided from its river source, the weaker the proxy relationship was with modelled data and other corals, due to mixing gradients and currents. Nevertheless, we demonstrate that two coral Ba / Ca and luminescence (G / B) records influenced by the same watershed are reproducible. Furthermore, a strong Ba / Ca relationship was observed between two cores from distant watersheds, with baseline averages in agreement with modelled sediment runoff data. As humic acids behave conservatively in the water column, luminescence (G / B) data gave the highest regional correlations between cores, and showed the most consistent relationship with site specific modelled discharge. No statistical relationship was observed between cores in terms of interannual δ18Osw and δ13C, meaning corals were recording a localised signal at their respective sites, confounded by vital effects. Comparing proxy baseline averages and mean seasonal cycles provided a good overview of the runoff dynamics of the bay system.

Investigating the interactions among river flow, salinity and sea ice using a global coupled atmosphere—ocean—ice model

1997 ◽  
Vol 25 ◽  
pp. 121-126 ◽  
Author(s):  
James R. Miller ◽  
Gary L. Russell
Keyword(s):  
Sea Ice ◽  
River Discharge ◽  
River Flow ◽  
Ice Cover ◽  
The Arctic ◽  
Fram Strait ◽  
Ice Flow ◽  
Basin Scale ◽  
Flow Through ◽  
Ice Model

A global coupled atmosphere-ocean-ice model is used to examine the interdependence among several components of the hydrologic cycle in the Arctic Ocean, including river discharge, sea-ice cover, and the flow of sea ice through Fram Strait. Since the ocean model has a free surface, fresh-water inflow from rivers is added directly to the ocean. The timing of the peak spring river flow depends on snowmelt runoff and its subsequent routing through the river system. Thermodynamic sea ice is included, and a new sea-iee advection scheme is described. The model’s river discharge affects salinity at the mouth of large rivers. The effect of the river discharge on sea-ice cover is not clear, either locally or at the basin scale. There is significant inter-annual variability of ice flow through Fram Strait, but the model’s flow is about half of that observed. The anomalous ice flow through Fram Strait is most highly correlated with the meridional wind stress. Potential implications for the “great salinity” anomaly are discussed.

scholarly journals Investigating the interactions among river flow, salinity and sea ice using a global coupled atmosphere—ocean—ice model

1997 ◽  
Vol 25 ◽  
pp. 121-126 ◽  
Author(s):  
James R. Miller ◽  
Gary L. Russell
Keyword(s):  
Sea Ice ◽  
River Discharge ◽  
River Flow ◽  
Ice Cover ◽  
The Arctic ◽  
Fram Strait ◽  
Ice Flow ◽  
Basin Scale ◽  
Flow Through ◽  
Ice Model

A global coupled atmosphere-ocean-ice model is used to examine the interdependence among several components of the hydrologic cycle in the Arctic Ocean, including river discharge, sea-ice cover, and the flow of sea ice through Fram Strait. Since the ocean model has a free surface, fresh-water inflow from rivers is added directly to the ocean. The timing of the peak spring river flow depends on snowmelt runoff and its subsequent routing through the river system. Thermodynamic sea ice is included, and a new sea-iee advection scheme is described. The model’s river discharge affects salinity at the mouth of large rivers. The effect of the river discharge on sea-ice cover is not clear, either locally or at the basin scale. There is significant inter-annual variability of ice flow through Fram Strait, but the model’s flow is about half of that observed. The anomalous ice flow through Fram Strait is most highly correlated with the meridional wind stress. Potential implications for the “great salinity” anomaly are discussed.

scholarly journals Does HadGEM3-GC3.1 GCM overestimate land precipitation at high resolution? A constraint based on observed river discharge

2021 ◽  
Author(s):  
Omar V. Müller ◽  
Pier Luigi Vidale ◽  
Benoît Vannière ◽  
Reinhard Schiemann ◽  
Patrick C. McGuire
Keyword(s):  
High Resolution ◽  
Bias Correction ◽  
River Discharge ◽  
River Flow ◽  
River Mouth ◽  
Mountainous Regions ◽  
Novel Approach ◽  
The World ◽  
Global Land ◽  
Precipitation Increase

AbstractPrevious studies showed that high-resolution GCMs overestimate land precipitation when compared against observation-based data. Particularly, high-resolution HadGEM3-GC3.1 shows a significant precipitation increase in mountainous regions, where the scarcity of gauge stations increases the uncertainty of gridded observations and reanalyses. This work evaluates such precipitation uncertainties indirectly through the assessment of river discharge, considering that an increase of ~10% in land precipitation produces ~28% more runoff when the resolution is enhanced from 1° to 0.25°, and ~50% of the global runoff is produced in 27% of global land dominated by mountains. We diagnosed the river flow by routing the runoff generated by HadGEM3-GC3.1 low- and high-resolution simulations. The river flow is evaluated using a set of 344 monitored catchments distributed around the world. We also infer the global discharge by constraining the simulations with observations following a novel approach that implies bias correction in monitored rivers with two methods, and extension of the correction to the river mouth, and along the coast. Our global discharge estimate is 47.4±1.6×103km3yr−1, which is closer to the original high-resolution estimate (50.5 × 103km3yr−1) than to the low-resolution (39.6 × 103km3yr−1). The assessment suggests that high-resolution simulations performbetter in mountainous regions, either because the better-defined orography favours the placement of precipitation in the correct catchment, leading to a more accurate distribution of runoff, or the orographic precipitation increases, reducing the dry runoff bias of coarse resolution simulations. However, high-resolution slightly increases wet biases in catchments dominated by flat terrain. The improvement of model parameterizations and tuning may reduce the remaining errors in high-resolution simulations.

scholarly journals How winds and river discharge affect circulation in a mesotidal estuary, San Francisco Bay, USA

2022 ◽  
Author(s):  
Qianqian Liu ◽  
Huijie Xue ◽  
Fei Chai ◽  
Zhengui Wang ◽  
Yi Chao ◽  
...  
Keyword(s):  
San Francisco ◽  
River Discharge ◽  
River Flow ◽  
San Francisco Bay ◽  
Integrated System ◽  
Wind Forcing ◽  
Salt Flux ◽  
Tidal Range ◽  
Salt Intrusion

Previous studies suggest importance of wind forcing on salt intrusion length and salt flux in river-dominated microtidal estuaries (with tidal range < 2 m). In this study, we investigate the role of wind forcing on salt intrusion in a mesotidal estuary, San Francisco Bay (SFB), with tidal ranges between 2 m and 4 m, through an open-source model of high transferability, the Semi-implicit Cross-scale Hydroscience Integrated System Model (SCHISM). Meanwhile, we investigate circulation and salinity variation of San Francisco Bay. The model’s performance in hydrodynamics at tidal, spring/neap and seasonal time scales is validated through model-observation comparisons. Through realistically forced and process-oriented experiments, we demonstrate that spring/neap tides can cause fortnightly variations in salinity and currents by modulating vertical mixing and stratification; and seasonal variability of circulation in North Bay is determined by change of river discharge and modified by winds, while in South Bay it is dominated by wind-driven flows. Furthermore, we revealed the role of wind on X2 (the distance from the Golden Gate Bridge to the 2-PSU isohaline at the bottom). The model results show that X2 is primarily influenced by river flow and proportional to river flow to the ¼ power. Meanwhile, wind plays a secondary role in modifying X2 by increasing X2 from 0 to 5 km during low discharge period, while spring/neap tide modulation on X2 is negligible but important for salt balance in sub-regions downstream of X2.

scholarly journals KEANDALAN EMBUNG LAMBADEUK UNTUK PEMENUHAN AIR BERSIH DI DAERAH PESISIR KECAMATAN PEUKAN BADA ACEH BESAR

2018 ◽  
Vol 1 (4) ◽  
pp. 971-984
Author(s):  
Setia Budi ◽  
Azmeri Azmeri ◽  
Syamsidik Syamsidik
Keyword(s):  
Coastal Area ◽  
Water Demand ◽  
River Flow ◽  
Dry Season ◽  
Clean Water ◽  
Wet Season ◽  
Microsoft Excel ◽  
Non Linear ◽  
Dam Operation ◽  
Inflow Discharge

Abstract : Water demand fulfillment in coastal area of Peukan Bada Sub District is still complicated. Peukan Bada Community in coastal area currently still depends on well water. The existence of Lambadeuk Small Dam located in Peukan Bada Sub District – Aceh Besar, which River Flow Area (DAS) is ± 2.27 Km², is expected to be able in fulfilling clean water demand. The objectives of this research are to find out water supply, to optimize the operation and to obtain the reliability of Lambadeuk Small Dam Operation. The method used in operating the small dam is analyzed by Non Linear Program using Solver Microsoft Excel. In optimizing the operation, it is divided into three season conditions. The highest inflow discharge of dry season is in January which is 0.222 m3/sec or 0.594 MCM, while the highest inflow discharge of normal season is in December which is 0.294 m3/sec or 0.787 MCM, and the highest inflow discharge of wet season is in November which is 0. 463 m3/sec or 1.199 MCM. The projection of population and clean water demand for population need in coastal area of Peukan Bada Sub District can be described as for population 5,954 in 2015, the clean water demand is 0.0099 m3/sec so that in 2035, the population will become 10,534 and the clean water demand will be 0.0176 m3/sec. The average inflow from 2015 to 2035 for dry season is 4.031 MCM, for normal season is 5.816 MCM, and for wet season is 9.077 MCM. Water release is 0.312 MCM, and basic water demand is 0.556 MCM. Optimization reliability of Lambadeuk Small Dam Operation is reliable and 100% can fulfill the water demand in the downstream of the small dam, and the management organizer of Lambadeuk Small Dam can also expand service area of clean water demand in the coastal area of Peukan Bada Sub District – Aceh Besar. Abstrak: Dalam pemenuhan kebutuhan air bersih di daerah pesisir Kecamatan Peukan Bada masih kesulitan untuk kebutuhan air bersih. Selama ini masyarakat di daerah pesisir masih mengandalkan air sumur. Dengan adanya Embung Lambadeuk yang terletak di Kecamatan Peukan Bada Kabupaten Aceh Besar, yang mempunyai luas Daerah Aliran Sungai (DAS) ± 2,27 Km², mampu untuk pemenuhan kebutuhan air bersih. Tujuan dari penelitian ini untuk mengetahui ketersediaan air, mengoptimalkan pengopersian dan mendapatkan keandalan pengopersian Embung Lambadeuk. Pada penelitian ini metode pengoperasian embung yang dianalisis menggunakan program Non Linear dengan solver Microsoft Excel. Dalam optimasi pengoperasian dikelompokan dalam tiga kondisi tahun musim, dimana kondisi tahun musim kering debit Inflow yang tertinggi berada pada bulan Januari sebesar 0,222 m3/dt dengan kapasitas  0,594 MCM, pada kondisi tahun normal debit yang tertinggi berada pada bulan  Desember sebesar 0,294 m3/dt  dengan kapasitas  0,787 MCM dan pada kondisi tahun basah debit yang tertinggi pada bulan Nopember sebesar 0,463 m3/dt dengan kapasitas  1,199 MCM. Proyeksi jumlah penduduk dan kebutuhan air bersih untuk pemenuhan penduduk di pesisir Kecmatan Peukan Bada, tahun 2015 dengan jumlah penduduk sebesar 5.954 jiwa, kebutuhan air bersih 0,0099 m3/dt dan Tahun 2035 jumlah penduduk sebesar 10.534 jiwa, kebutuhan air bersih 0,0176 m3/dt. Untuk Inflow tahun kering dari Tahun 2015 sampai Tahun 2035 Inflow rata-rata tahunan sebesar 4,031 MCM, tahun normal dari Tahun 2015 sampai tahun 2035 Inflow rata-rata sebesar 5,816 MCM, dan tahun basah Inflow rata-rata tahunan sebesar 9,077 MCM. Release air sebesar 0.312 MCM, dan kebutuhan air baku sebesar 0,556 MCM. Hasil yang dicapai adalah Pengoperasian Embung yang Optimal dan Keandalan Pengoperasian Embung. Dimana Keandalan Pengoperasian Embung Lambadeuk sangat berpengaruh dari volume dan periode waktu, dan terhadap Manajemen pengelola Embung Lambadeuk, bisa mengambil langkah-langkah untuk memperluas daerah layanan kebutuhan air bersih di pesisir Kecamatan Peukan Bada Aceh Besar.

scholarly journals Large-scale scour in response to tidal dominance in estuaries

2021 ◽  
Author(s):  
Jasper Leuven ◽  
Daan van Keulen ◽  
Jaap Nienhuis ◽  
Alberto Canestrelli ◽  
Ton Hoitink
Keyword(s):  
Sediment Transport ◽  
River Discharge ◽  
Large Scale ◽  
River Flow ◽  
Tidal Flow ◽  
Tidal Energy ◽  
Local Flow ◽  
Flow Acceleration ◽  
Flow Through ◽  
Tide Interaction

&lt;p&gt;Channel beds in estuaries and deltas often exhibit a local depth maximum at a location close to the coast. There are two known causes of large-scale (i.e. &gt;10 river widths along-channel) channel bed scours: width constriction and draw down during river discharge extremes, both creating a local flow acceleration. Here, we systematically investigate a potential third mechanism. We study the effect of tidal dominance on the equilibrium channel bed in estuaries with a 1D-morphodynamic model. In estuaries, a morphodynamic equibrium is reached when the net (seaward) transport matches the upstream supply along the entire reach. The residual (river) current and river-tide interactions create seaward transport. Herein, river-tide interactions represent the seaward advection of tide-induced suspended sediment by the river flow. Tidal asymmetry typically creates landward transport. The main reason for scour formation is the amplification of tidal flow through funnelling of tidal energy. Only for a scouring profile the drop in river induced current magnitude reduces the river-tide interaction term, so that the net sediment transport matches the upstream sediment transport. When tidal influence is relatively large, and when channel convergence is strong, a equilibrium is only obtained with a scouring profile. We propose a predictor dependent on the width convergence, quantified as S&lt;sub&gt;B&lt;/sub&gt;, and on the ratio between the specific peak tidal discharge at the mouth and the specific river discharge at the landward boundary (q&lt;sub&gt;tide&lt;/sub&gt;/q&lt;sub&gt;river&lt;/sub&gt;). Scours develop if (q&lt;sub&gt;tide&lt;/sub&gt;/q&lt;sub&gt;river&lt;/sub&gt;)/S&lt;sub&gt;B&lt;/sub&gt; exceeds 0.3. These results are independent of scale and allow the prediction of scour in estuaries under future changes.&lt;/p&gt;

scholarly journals Future projections of High Atlas snowpack and runoff under climate change

2020 ◽  
Author(s):  
Alexandre Tuel ◽  
Nabil El Moçayd ◽  
Moulay Driss Hasnaoui ◽  
Elfatih A. B. Eltahir
Keyword(s):  
Climate Change ◽  
River Discharge ◽  
River Flow ◽  
Climate Modeling ◽  
Large Fraction ◽  
Future Climate Change ◽  
Wet Season ◽  
High Atlas ◽  
Snow Model ◽  
Stressed Region

Abstract. The High Atlas, culminating at more than 4000 m, is the water tower of Morocco. While plains receive less than 400 mm of precipitation in an average year, the mountains can get twice as much, often in the form of snow between November and March. Snowmelt thus accounts for a large fraction of the river discharge in the region, and is particularly critical during spring, as the wet season ends but the need for irrigation increases. In the same region, future climate change projections point towards a significant decline in precipitation and enhanced warming of temperature. Understanding how the High Atlas snowpack will evolve under such trends is therefore of paramount importance to make informed projections of future water availability in Morocco. Here, we build on previous research results on snow and climate modeling in the High Atlas to make detailed projections of snowpack and river flow response to climate change in this region. Using a distributed energy balance snow model based on SNOW-17, high-resolution climate simulations over Morocco, and a panel regression framework to relate runoff ratios to regional meteorological conditions, we quantify the severe declines in snowpack and river discharge that are to be expected, even under a scenario of substantial mitigation of emissions. Our results have important implications for water resources planning and sustainability of agriculture in this already water-stressed region.

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