scholarly journals Hydrodynamic changes impacted by the waterway capital dredging in Cikarang Bekasi Laut channel, West Java, Indonesia

2020 ◽  
Vol 15 (2) ◽  
pp. 450-459
Author(s):  
Harman Ajiwibowo ◽  
Munawir B. Pratama
Keyword(s):  
Water Level ◽  
Cross Sections ◽  
River Discharge ◽  
River Flow ◽  
Wet Season ◽  
West Java ◽  
Tidal Elevation ◽  
Discharge Data ◽  
Data Dredging ◽  
The Impact

Abstract This paper presents one-dimensional numerical modeling using MIKE 11 to simulate the impact of capital dredging on the hydrodynamics of the Cikarang Bekasi Laut (CBL) channel flow. The CBL channel is located in Bekasi Regency, West Java Province, Indonesia. The river discharges upstream, and tidal fluctuations at the sea boundary were the governing parameters of the hydrodynamic model. Data such as river centerline, cross-sections, tidal elevation, and river discharges were compiled to construct the model. The instantaneous record of water level and river discharge data were used as model validation. The model results give decent validation when compared to water level and river discharge field data. Dredging on the canal is planned to be carried out across 19 km from the estuary to the upstream to allow large vessel navigation. The modeling results show that during the wet season, dredging affects the water level and river flow up to 25 km upstream, while during the dry season, dredging affects the hydrodynamics only up to 20 km upstream. It can be concluded that the canal dredging does not have a significant impact in terms of surface water elevation in the canal upstream. The critical finding is that the bed shear stress is significantly increased upstream of the dredging plan at kilometer 19, showing that there is potential riverbed erosion threat in the area. It is recommended to conduct a sedimentation study to predict the impact of sedimentation change from the dredging.

Improving SAR Altimeter processing over the coastal zone and inland waters - the ESA HYDROCOASTAL project

2021 ◽  
Author(s):  
David Cotton ◽  
Keyword(s):  
Coastal Zone ◽  
Test Data ◽  
River Discharge ◽  
Altimeter Data ◽  
Inland Waters ◽  
Data Sets ◽  
Data Set ◽  
Discharge Data ◽  
Processing Algorithms ◽  
The Impact

<p><strong>Introduction</strong></p><p>HYDROCOASTAL is a two year project funded by ESA, with the objective to maximise exploitation of SAR and SARin altimeter measurements in the coastal zone and inland waters, by evaluating and implementing new approaches to process SAR and SARin data from CryoSat-2, and SAR altimeter data from Sentinel-3A and Sentinel-3B. Optical data from Sentinel-2 MSI and Sentinel-3 OLCI instruments will also be used in generating River Discharge products.</p><p>New SAR and SARin processing algorithms for the coastal zone and inland waters will be developed and implemented and evaluated through an initial Test Data Set for selected regions. From the results of this evaluation a processing scheme will be implemented to generate global coastal zone and river discharge data sets.</p><p>A series of case studies will assess these products in terms of their scientific impacts.</p><p>All the produced data sets will be available on request to external researchers, and full descriptions of the processing algorithms will be provided</p><p> </p><p><strong>Objectives</strong></p><p>The scientific objectives of HYDROCOASTAL are to enhance our understanding  of interactions between the inland water and coastal zone, between the coastal zone and the open ocean, and the small scale processes that govern these interactions. Also the project aims to improve our capability to characterize the variation at different time scales of inland water storage, exchanges with the ocean and the impact on regional sea-level changes</p><p>The technical objectives are to develop and evaluate  new SAR  and SARin altimetry processing techniques in support of the scientific objectives, including stack processing, and filtering, and retracking. Also an improved Wet Troposphere Correction will be developed and evaluated.</p><p><strong>Project  Outline</strong></p><p>There are four tasks to the project</p><ul><li>Scientific Review and Requirements Consolidation: Review the current state of the art in SAR and SARin altimeter data processing as applied to the coastal zone and to inland waters</li> <li>Implementation and Validation: New processing algorithms with be implemented to generate a Test Data sets, which will be validated against models, in-situ data, and other satellite data sets. Selected algorithms will then be used to generate global coastal zone and river discharge data sets</li> <li>Impacts Assessment: The impact of these global products will be assess in a series of Case Studies</li> <li>Outreach and Roadmap: Outreach material will be prepared and distributed to engage with the wider scientific community and provide recommendations for development of future missions and future research.</li> </ul><p> </p><p><strong>Presentation</strong></p><p>The presentation will provide an overview to the project, present the different SAR altimeter processing algorithms that are being evaluated in the first phase of the project, and early results from the evaluation of the initial test data set.</p><p> </p>

scholarly journals Analytical approach for determining the mean water level profile in an estuary with substantial fresh water discharge

2016 ◽  
Vol 20 (3) ◽  
pp. 1177-1195 ◽  
Author(s):  
Huayang Cai ◽  
Hubert H. G. Savenije ◽  
Chenjuan Jiang ◽  
Lili Zhao ◽  
Qingshu Yang
Keyword(s):  
Water Level ◽  
Fresh Water ◽  
River Discharge ◽  
River Flow ◽  
Water Discharge ◽  
Value Theory ◽  
Velocity Amplitude ◽  
Mean Water Level ◽  
The Mean ◽  
Fresh Water Discharge

Abstract. The mean water level in estuaries rises in the landward direction due to a combination of the density gradient, the tidal asymmetry, and the backwater effect. This phenomenon is more prominent under an increase of the fresh water discharge, which strongly intensifies both the tidal asymmetry and the backwater effect. However, the interactions between tide and river flow and their individual contributions to the rise of the mean water level along the estuary are not yet completely understood. In this study, we adopt an analytical approach to describe the tidal wave propagation under the influence of substantial fresh water discharge, where the analytical solutions are obtained by solving a set of four implicit equations for the tidal damping, the velocity amplitude, the wave celerity, and the phase lag. The analytical model is used to quantify the contributions made by tide, river, and tide–river interaction to the water level slope along the estuary, which sheds new light on the generation of backwater due to tide–river interaction. Subsequently, the method is applied to the Yangtze estuary under a wide range of river discharge conditions where the influence of both tidal amplitude and fresh water discharge on the longitudinal variation of the mean tidal water level is explored. Analytical model results show that in the tide-dominated region the mean water level is mainly controlled by the tide–river interaction, while it is primarily determined by the river flow in the river-dominated region, which is in agreement with previous studies. Interestingly, we demonstrate that the effect of the tide alone is most important in the transitional zone, where the ratio of velocity amplitude to river flow velocity approaches unity. This has to do with the fact that the contribution of tidal flow, river flow, and tide–river interaction to the residual water level slope are all proportional to the square of the velocity scale. Finally, we show that, in combination with extreme-value theory (e.g. generalized extreme-value theory), the method may be used to obtain a first-order estimation of the frequency of extreme water levels relevant for water management and flood control. By presenting these analytical relations, we provide direct insight into the interaction between tide and river flow, which will be useful for the study of other estuaries that experience substantial river discharge in a tidal region.

scholarly journals Impact of climate change on freshwater ecosystems: a global-scale analysis of ecologically relevant river flow alterations

2010 ◽  
Vol 14 (5) ◽  
pp. 783-799 ◽  
Author(s):  
P. Döll ◽  
J. Zhang
Keyword(s):  
Climate Change ◽  
River Discharge ◽  
River Flow ◽  
Flow Regimes ◽  
Freshwater Ecosystems ◽  
Land Area ◽  
Impact Of Climate Change ◽  
Water Withdrawals ◽  
The Impact

Abstract. River flow regimes, including long-term average flows, seasonality, low flows, high flows and other types of flow variability, play an important role for freshwater ecosystems. Thus, climate change affects freshwater ecosystems not only by increased temperatures but also by altered river flow regimes. However, with one exception, transferable quantitative relations between flow alterations and ecological responses have not yet been derived. While discharge decreases are generally considered to be detrimental for ecosystems, the effect of future discharge increases is unclear. As a first step towards a global-scale analysis of climate change impacts on freshwater ecosystems, we quantified the impact of climate change on five ecologically relevant river flow indicators, using the global water model WaterGAP 2.1g to simulate monthly time series of river discharge with a spatial resolution of 0.5 degrees. Four climate change scenarios based on two global climate models and two greenhouse gas emissions scenarios were evaluated. We compared the impact of climate change by the 2050s to the impact of water withdrawals and dams on natural flow regimes that had occurred by 2002. Climate change was computed to alter seasonal flow regimes significantly (i.e. by more than 10%) on 90% of the global land area (excluding Greenland and Antarctica), as compared to only one quarter of the land area that had suffered from significant seasonal flow regime alterations due to dams and water withdrawals. Due to climate change, the timing of the maximum mean monthly river discharge will be shifted by at least one month on one third on the global land area, more often towards earlier months (mainly due to earlier snowmelt). Dams and withdrawals had caused comparable shifts on less than 5% of the land area only. Long-term average annual river discharge is predicted to significantly increase on one half of the land area, and to significantly decrease on one quarter. Dams and withdrawals had led to significant decreases on one sixth of the land area, and nowhere to increases. Thus, by the 2050s, climate change may have impacted ecologically relevant river flow characteristics more strongly than dams and water withdrawals have up to now. The only exception refers to the decrease of the statistical low flow Q90, with significant decreases both by past water withdrawals and future climate change on one quarter of the land area. However, dam impacts are likely underestimated by our study. Considering long-term average river discharge, only a few regions, including Spain, Italy, Iraq, Southern India, Western China, the Australian Murray Darling Basin and the High Plains Aquifer in the USA, all of them with extensive irrigation, are expected to be less affected by climate change than by past anthropogenic flow alterations. In some of these regions, climate change will exacerbate the discharge reductions, while in others climate change provides opportunities for reducing past reductions. Emissions scenario B2 leads to only slightly reduced alterations of river flow regimes as compared to scenario A2 even though emissions are much smaller. The differences in alterations resulting from the two applied climate models are larger than those resulting from the two emissions scenarios. Based on general knowledge about ecosystem responses to flow alterations and data related to flow alterations by dams and water withdrawals, we expect that the computed climate change induced river flow alterations will impact freshwater ecosystems more strongly than past anthropogenic alterations.

scholarly journals Climate change impact to dam Operation, case study of Darma Dam, West Java

2022 ◽  
Vol 1212 (1) ◽  
pp. 012031
Author(s):  
A A Kuntoro ◽  
D T Ramadhani ◽  
A M S Idris ◽  
M Farid ◽  
M B Adityawan ◽  
...  
Keyword(s):  
Climate Change ◽  
Present Condition ◽  
Water Volume ◽  
Adaptation To Climate Change ◽  
Wet Season ◽  
West Java ◽  
Industrial Sectors ◽  
Dam Operation ◽  
Average Water ◽  
The Impact

Abstract Darma Dam is located in the upstream of Cisanggarung River, Kuningan Regency, West Java Province. Darma Dam construction dated from about 1922. Indonesian government continued the construction and began operating in 1962. With effective storage of about 40 million m3, Darma Dam provides water for about 22 thousand irrigation areas and bulk water for several cities and regencies. Several problems encountered in Darma Dam operation and water management are 1) increasing water demand from domestic and industrial sectors, and 2) high inflow variation during the dry and wet season, resulting in a large amount of water spill from the dam spillway. This paper addressed the impact of climate change on the inflow variation of Darma Dam in the dry and wet seasons. Further analysis shows average water spills from the spillway during the wet season may increase from about 12 million m3/year in the present condition to about 20 million m3/year in 2020-2050, while the average water volume during the dry season may reduce from 22.5 million m3 in the present condition to about 20.7 million m3 in 2020-2050. This study suggests that dam operation need adjustment in the future as part of adaptation to climate change.

scholarly journals Features of the balance structure formation of groundwater withdrawal and its effect on river flow at a subsoil water level drawdown

2019 ◽  
Vol 46 (3) ◽  
pp. 247-258
Author(s):  
S. O. Grinevsky ◽  
V. S. Sporyshev
Keyword(s):  
Water Balance ◽  
Water Level ◽  
River Flow ◽  
Groundwater Withdrawal ◽  
Intermediate Water ◽  
Subsoil Water ◽  
Balance Structure ◽  
The Impact ◽  
Subsoil Water Level ◽  
Infiltration Recharge

The balance structure of the pumpage sourses of riverside water-intakes, developing a subsoil aquifer or intermediate water that hydraulically interacts with it, can show the effect of the processes of water balance adjustment in the unsaturated zone to the accompanying subsoil water level drawdown. In this case, because of the shallow depth to subsoil water, its level drop due to water withdrawal causes a decrease in evapotranspiration and an increase in groundwater infiltration recharge. These processes have their effect on the balance structure of usable water resources as components of natural and involved resources and reduce the impact of groundwater pumping on river flow. Analysis of the operational data of the Sudogda waterintake in Vladimir oblast and geohydrological modeling were used to evaluate variations of the groundwater evaportanspiration losses and infiltration recharge and their role in the water balance structure of reserves of a field and in the impact of groundwater withdrawal on river flow.

scholarly journals Brief communication: The role of using precipitation or river discharge data when assessing global coastal compound flooding

2020 ◽  
Vol 20 (6) ◽  
pp. 1765-1782 ◽  
Author(s):  
Emanuele Bevacqua ◽  
Michalis I. Vousdoukas ◽  
Theodore G. Shepherd ◽  
Mathieu Vrac
Keyword(s):  
River Discharge ◽  
Large Scale ◽  
Storm Surges ◽  
High Water ◽  
Small Rivers ◽  
Water Runoff ◽  
Discharge Data ◽  
Physical Mechanisms ◽  
Catchment Size ◽  
The Impact

Abstract. Interacting storm surges and high water runoff can cause compound flooding (CF) in low-lying coasts and river estuaries. The large-scale CF hazard has been typically studied using proxies such as the concurrence of storm surge extremes either with precipitation or with river discharge extremes. Here the impact of the choice of such proxies is addressed employing state-of-the-art global datasets. Although they are proxies of diverse physical mechanisms, we find that the two approaches show similar CF spatial patterns. On average, deviations are smaller in regions where assessing the actual CF is more relevant, i.e. where the CF potential is high. Differences between the two assessments increase with the catchment size, and our findings indicate that CF in long rivers (catchment ≳5–10×103 km2) should be analysed using river discharge data. The precipitation-based assessment allows for considering local-rainfall-driven CF and CF in small rivers not resolved by large-scale datasets.

Discharge estimation and monitoring extreme events by satellite altimetry

2020 ◽  
Author(s):  
Rossella Belloni ◽  
Stefania Camici ◽  
Angelica Tarpanelli
Keyword(s):  
Time Series ◽  
Water Level ◽  
River Discharge ◽  
Satellite Altimetry ◽  
Global Scale ◽  
Discharge Time ◽  
Discharge Data ◽  
The World ◽  
Daily Discharge ◽  
Rating Curves

<p>In view of recent dramatic floods and drought events, the detection of trends in the frequency and magnitude of long time series of flood data is of scientific interest and practical importance. It is essential in many fields, from climate change impact assessment to water resources management, from flood forecasting to drought monitoring, for the planning of future water resources and flood protection systems. <br>To detect long-term changes in river discharge a dense, in space and time, network of monitoring stations is required. However, ground hydro-meteorological monitoring networks are often missing or inadequate in many parts of the world and the global supply of the available river discharge data is often restricted, preventing to identify trends over large areas.  <br>The most direct method of deriving such information on a global scale involves satellite earth observation. Over the last two decades, the growing availability of satellite sensors, and the results so far obtained in the estimation of river discharge from the monitoring of the water level through satellite radar altimetry has fostered the interest on this subject.  <br>Therefore, in the attempt to overcome the lack of long continuous observed time series, in this study satellite altimetry water level data are used to set-up a consistent, continuous and up-to-date daily discharge dataset for different sites across the world. Satellite-derived water levels provided by publicly available datasets (Podaac, Dahiti, River& Lake, Hydroweb and Theia) are used along with available ground observed river discharges to estimate rating curves. Once validated, the rating curves are used to fill and extrapolate discharge data over the whole period of altimetry water level observations. The advantage of using water level observations provided by the various datasets allowed to obtain discharge time series with improved spatio-temporal coverages and resolutions, enabling to extend the study on a global scale and to efficiently perform the analysis even for small to medium-sized basins.  <br>Long continuous discharge time series so obtained are used to perform a global trend analysis on extreme flood and drought events. Specifically, annual maximum discharge and peak-over threshold values are extracted from the simulated daily discharge time series, as proxy variables of independent flood events. For flood and drought events, a trend analysis is carried out to identify changes in the frequency and magnitude of extreme events through the Mann-Kendall (M-K) test and a linear regression model between time and the flood magnitude.  <br>The analysis has permitted to identify areas of the world prone to floods and drought, so that appropriate actions for disaster risk mitigation and continuous improvement in disaster preparedness, response, and recovery practices can be adopted. </p>

scholarly journals Development and validation of a global dynamical wetlands extent scheme

2012 ◽  
Vol 9 (1) ◽  
pp. 405-440 ◽  
Author(s):  
T. Stacke ◽  
S. Hagemann
Keyword(s):  
River Discharge ◽  
River Flow ◽  
Central Africa ◽  
Global Scale ◽  
Max Planck ◽  
Discharge Data ◽  
Wetland Extent ◽  
Wetland Processes ◽  
Development And Validation ◽  
Good Agreement

Abstract. In this study we present the development of the dynamical wetland extent scheme (DWES) and its validation against present day wetland observations. The DWES is a simple, global scale hydrological scheme that solves the water balance of wetlands and estimates their extent dynamically. The extent depends on the balance of water flows in the wetlands and the slope distribution within the grid cells. In contrast to most models, the DWES is not directly calibrated against wetland extent observations. Instead, wetland affected river discharge data are used to optimize global parameters of the model. The DWES is not a complete hydrological model by itself but implemented into the Max Planck Institute – Hydrology Model (MPI-HM). However, it can be transferred into other models as well. For present climate, the model validation reveals a good agreement between the occurrence of simulated and observed wetlands on the global scale. The best result is achieved for the northern hemisphere where not only the wetland distribution pattern but also their extent is simulated reasonably well by the DWES. However, the wetland fraction in the tropical parts of South America and Central Africa is strongly overestimated. The simulated extent dynamics correlate well with monthly inundation variations obtained from satellite for most locations. Also, the simulated river discharge is affected by wetlands resulting in a delay and mitigation of peak flows. Compared to simulations without wetlands, we find locally increased evaporation and decreased river flow into the oceans due to the implemented wetland processes. In summary, the validation analysis demonstrates the DWES' ability to simulate the global distribution of wetlands and their seasonal variations. Thus, the dynamical wetland extent scheme can provide hydrological boundary conditions for wetland related studies. In future applications, the DWES should be implemented into an earth system model to study feedbacks between wetlands and climate.

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.

scholarly journals Hydrology of the Po River: looking for changing patterns in river discharge

2012 ◽  
Vol 9 (5) ◽  
pp. 6689-6713
Author(s):  
A. Montanari
Keyword(s):  
Water Resources ◽  
River Discharge ◽  
River Flow ◽  
Temporal Distribution ◽  
Hydrological Regime ◽  
Po River ◽  
Water Abundance ◽  
Changing Patterns ◽  
The Impact

Abstract. Scientists and public administrators are devoting increasing attention to the Po River, in Italy, in view of concerns related to the impact of increasing urbanisation and exploitation of water resources. A better understanding of the hydrological regime of the river is necessary to improve water resources management and flood protection. In particular, the analysis of the effects of hydrological and climatic change is crucial for planning sustainable development and economic growth. An extremely interesting issue is to inspect to what extent river flows can be naturally affected by the occurrence of long periods of water abundance or scarcity, which can be erroneously interpreted as irreversible changes due to human impact. In fact, drought and flood periods alternatively occurred in the recent past in the form of long term cycles. This paper presents advanced graphical and analytical methods to gain a better understanding of the temporal distribution of the Po River discharge. In particular, we present an analysis of river flow variability and memory properties to better understand natural patterns and in particular long term changes, which may affect the future flood risk and availability of water resources.

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