scholarly journals KAJIAN HIDROLOGI DAN ANALISA KAPASITAS TAMPANG SUNGAI KRUENG LANGSA BERBASIS HEC-HMS DAN HEC-RAS

2015 ◽  
Vol 1 (1) ◽  
pp. 15-28
Author(s):  
Ichsan Syahputra

Krueng Langsa  is a river crossing Langsa City the position is in the middle of residential and potentially catastrophic spills seasonal flooding. Krueng Langsa River watershed has an area of 126 km2, with a rainfall of 2300 mm / year and includes areas with relatively high rainfall. In the upper part of the river flow characteristics along the hills, while the central part of the narrowing of the river in the extreme. Hydrologic simulation based on rainfall data using HEC-HMS software obtained flood discharge of 59.30 m³ / sec. Passing the analysis of flood discharge capacity obtained on existing cross-section of 60.07 m³ / sec which is almost close to the value of the existing flood discharge based on the model HEC-HMS. HEC-RAS analysis results with simulation input Q2 years, to 140 pieces of the cross section illustrates that almost all river basins experienced flooding conditions (overflow), and only a few parts that are not experiencing flooding conditions. This is because the flood water level exceeds the elevation of the bank. Scenario flood control is done by normalizing the river, which enlarge the dimensions of the existing river with a wide cross-section of the river on average 20 m to 60 m and planning at the river levee embankment crest elevation +2.00 m and surveillance (freeboard) 0.50 m of surface water flooding . At the mouth of the river, starting from the point STA.0 + 000 to STA.2+ 000  planned use of the river revetment rock pile (Dump Stone). Both scenarios flood control can be recommended to reduce the flooding that occurred in the Krueng Langsa river.

2018 ◽  
Vol 1 (2) ◽  
Author(s):  
Ahmad Nasirudin ◽  
Sigit Winarto ◽  
Sudjati Sudjati

ABSTRACT Checkdam is a controlling building created because of the flow of water with a large enough sediment concentration, where the sediment comes from soil erosion in the upstream part of the river, to find out the analysis of hydrology, regarding its rainfall, analyze the flood discharge. With the form of a checkpoint in the village of Notorejo, it can prevent and reduce disasters due to the flow of sediments that are formulated in such a way that the river concerned can function normally and effectively in terms of two angles, namely flood control and river development. Rainfall based on calculation of log pearson type III on R20 is 100mm, and Flood Debit Plan 167 m3 / dt. The ability of the sediment capacity of 700,692 m3 / dt and the capacity of sediment capacity to remain 525,519. and able to withstand shear force and rolling stability, this discharge plan is useful for reducing sediment that enters the river salts and provides safety of surrounding agricultural areas due to erosion, stabilizes the riverbed, directs river flow and reduces the occurrence of breakdowns in bridge structures along the river flow mate. Keywords: checkdam, hydrology, sediment, flood discharge, stability. 


2020 ◽  
Vol 4 (2) ◽  
Author(s):  
Ridwan Abadi Akbar ◽  
Adwitya Bhaskara

<p align="center"><strong>Abstract.</strong></p><p>Floods always come suddenly and unexpectedly, and lots of people living in the flood-prone area can be the victims. As happened on February 2, 2020, a number of rice fields, roads, and houses belonging to the residents in the Parangjoho watershed, Eromoko District, Wonogiri, with 9.8-km river length and 32.59-km<sup>2</sup> area, was flooded due to heavy rain for some time which flushed the Eromoko area, therefore, the river flow could not accommodate the volume of water that entered and overflowed. This was what motivated researchers to calculate the design flood discharge to be able to carry out the flood control.</p><p>The methods of calculating the design flood discharge in the Parangjoho watershed used the Nakayasu Synthetic Unit Hydrograph (SUH) Method and the Soil Conservation Service (SCS) Method, using the rainfall data from the Bengawan Solo Central River Region at Parangjoho Station. The rainfall data used were from 2000 to 2019.</p>


Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4406
Author(s):  
Tadaharu Ishikawa ◽  
Hiroshi Senoo

The development process and flood control effects of the open-levee system, which was constructed from the mid-18th to the mid-19th centuries, on the Kurobe Alluvial Fan—a large alluvial fan located on the Japan Sea Coast of Japan’s main island—was evaluated using numerical flow simulation. The topography for the numerical simulation was determined from an old pictorial map in the 18th century and various maps after the 19th century, and the return period of the flood hydrograph was determined to be 10 years judging from the level of civil engineering of those days. The numerical results suggested the followings: The levees at the first stage were made to block the dominant divergent streams to gather the river flows together efficiently; by the completed open-levee system, excess river flow over the main channel capacity was discharged through upstream levee openings to old stream courses which were used as temporary floodways, and after the flood peak, a part of the flooded water returned to the main channel through the downstream levee openings. It is considered that the ideas of civil engineers of those days to control the floods exceeding river channel capacity, embodied in their levee arrangement, will give us hints on how to control the extraordinary floods that we should face in the near future when the scale of storms will increase due to the global climate change.


Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 507 ◽  
Author(s):  
Dariusz Wrzesiński ◽  
Leszek Sobkowiak

Identification of river flow regime and its possible changes caused by natural factors or human activity is one of major issues in modern hydrology. In such studies different approaches and different indicators can be used. The aim of this study is to determine changes in flow regime of the largest river in Poland—the Vistula, using new, more objectified coefficients and indices, based on data recorded in 22 gauges on the Vistula mainstream and 38 gauges on its tributaries in the multi-year period 1971–2010. The paper consists of three main parts: in the first part, in order to recognize changes in the flow regime characteristics along the Vistula, data from gauges located on the river mainstream were analyzed with the help of the theory of entropy. In the second part gauging stations on the Vistula mainstream and its tributaries were grouped; values of the newly introduced pentadic Pardé’s coefficient of flow (discharge) (PPC) were taken as the grouping criterion. In the third part of the study a novel method of determining river regime characteristics was applied: through the recognition of the temporal structure of hydrological phenomena and their changes in the annual cycle sequences of hydrological periods (characteristic phases of the hydrological cycle) on the Vistula River mainstream and its tributaries were identified and their occurrence in the yearly cycle was discussed. Based on the detected changes of the 73-pentad Pardé’s coefficients of flow four main types of rivers were distinguished. Transformation of the flow regime was reflected in the identified different sequences of hydrological periods in the average annual cycle. It was found that while transformation of the Vistula River regime occurred along its whole course, the most frequent changes were detected in its upper, mountainous reaches, under the influence of the flow characteristics of its tributaries. This allowed the Vistula to be considered the allochthonous river. These findings are interesting not only from a theoretical point of view, but they also can be valuable to stakeholders in the field of the Vistula River basin water management and hydrological forecasting, including flood protection, which has recently become a matter of growing concern due to the observed effects of climate change and human impact.


2013 ◽  
Vol 17 (1) ◽  
pp. 325-339 ◽  
Author(s):  
C. Schneider ◽  
C. L. R. Laizé ◽  
M. C. Acreman ◽  
M. Flörke

Abstract. Worldwide, flow regimes are being modified by various anthropogenic impacts and climate change induces an additional risk. Rising temperatures, declining snow cover and changing precipitation patterns will interact differently at different locations. Consequently, in distinct climate zones, unequal consequences can be expected in matters of water stress, flood risk, water quality, and food security. In particular, river ecosystems and their vital ecosystem services will be compromised as their species richness and composition have evolved over long time under natural flow conditions. This study aims at evaluating the exclusive impacts of climate change on river flow regimes in Europe. Various flow characteristics are taken into consideration and diverse dynamics are identified for each distinct climate zone in Europe. In order to simulate present-day natural flow regimes and future flow regimes under climate change, the global hydrology model WaterGAP3 is applied. All calculations for current and future conditions (2050s) are carried out on a 5' × 5' European grid. To address uncertainty, bias-corrected climate forcing data of three different global climate models are used to drive WaterGAP3. Finally, the hydrological alterations of different flow characteristics are quantified by the Indicators of Hydrological Alteration approach. Results of our analysis indicate that on the European scale, climate change can be expected to modify flow regimes remarkably. This is especially the case in the Mediterranean (due to drier conditions with reduced precipitation across the year) and in the boreal climate zone (due to reduced snowmelt, increased precipitation, and strong temperature rises). In the temperate climate zone, impacts increase from oceanic to continental. Regarding single flow characteristics, strongest impacts on timing were found for the boreal climate zone. This applies for both high and low flows. Flow magnitudes, in turn, will be predominantly altered in the Mediterranean but also in the Northern climates. At the end of this study, typical future flow regimes under climate change are illustrated for each climate zone.


2018 ◽  
Vol 7 (1) ◽  
pp. 26-29
Author(s):  
Asril Zevri

Abstract: Belawan River Basin is one of the watershed, which currently change the land use because of the increasing population and industrial development. Rainfall with high intensity can cause rapid runoff, causing flood around the plains of the river cross section. The purpose of this research is to determine the flood water level of Belawan Watershed and flood discharge return period. Scope of activity in this research is analyzing daily rainfall Belawan watershed with the flood-discharge return period. Scope of activity in this research is analyzing maximum daily rainfall Belawan Watershed, and simulating flood water level with HECRAS. The result of the study shows that the potency of Belawan watershed flood water level is caused by flood discharge at 25 to 100 years especially in the middle to downstream of river cross section that is between 0.7 m and 3.3 m. Keywords: Flood Discharge, Flood Level, Belawan Watershed, Software HECRAS. Abstrak: Daerah Aliran Sungai Belawan adalah salah satu DAS yang pada saat ini mengalami perubahan tata guna lahan seiring bertambahnya jumlah penduduk dan perkembangan industri. Curah hujan yang tinggi dapat mengakibatkan limpasan sehingga menimbulkan tinggi muka air banjir di sekitar dataran penampang sungai. Tujuan dari penelitian ini adalah untuk mensimulasi tinggi muka air banjir DAS Belawan dengan debit banjir periode kala ulangnya. Lingkup kegiatan dalam penelitian ini yaitu menganalisa curah hujan harian maksimum rata-rata DAS Belawan dan menganalisa debit banjir kala ulang 2 sampai dengan 100 tahun, mensimulasi tinggi muka air banjir dengan HECRAS. Hasil studi menunjukan potensi tinggi muka air banjir DAS Belawan terjadi akibat debit banjir periode kala ulang 25 sampai dengan 100 tahun khususnya  di bagian tengah sampai hilir penampang sungai yaitu berkisar antara 0.7 m sampai dengan 3.3 m. Kata kunci: Debit banjir, Tinggi Banjir, DAS Belawan, Software HECRAS.


2014 ◽  
Vol 8 (1) ◽  
pp. 1
Author(s):  
Sudarmanto ,

Placement of the weir in the river Batang Gadis will cause population anxiety in the village Pulungan which located upstream weir as far as 3 km, due to a weir can cause water surface profile of the river getting higher and ultimately to increase the pool of flooding in residential areas.Assuming modeling of river a uniform flow, river cross-section has a rectangular shape with width 50 m and 40 m, the roughness Manning 0.0025, the profile of water flow floods that occurred in 2 yaears, 25 years, and 100 years before and after the existing weir can be calculated by numerical integration methods.  From the calculation, the length of the water behind the weir is 1.4 km upstream towards the weir, which means that the depth of the water level rises to as far as 1.4 km and after that the depth of water before and after there the weir is same. Because the village Pulungan located 3 km to the upstream, the weir did not affect the increase in the flood waters in the village Pulungan. At 2 years flood discharge does not cause inundation in the village Pulungan, but the flood discharge 25 years and 100 years has led to inundation in the village Pulungan with the depth of each pool 0.971 m and 1.675 m. Keywords: uniform flow, numerical integration, inundation, flood discharge.


2015 ◽  
Vol 76 (1) ◽  
Author(s):  
Dato’ Ir. Syed Muhammad Shahabudin

It is said tluit civilization began and prospered when humans could control water; and that same civilization declined and vanished when that control is lost. Dams and other river flow barriers were built to harness and control water in the early days of civilisation in order to secure the benefits for human basic needs and comfort. Centuries later, more dams were built to cater for increasing population, especially in arid and semi-arid areas. But it is really in the past two centuries that many large-sized dams have been built to satisfy a wider range of development demands — hydropower, treated water supply, irrigation, flood control and environmental needs.Towards the second half of the last century, society came to realise that dams can cause significant negative social and environmental impacts that could outweigh the original economic benefits. Opponents of dams protest vehemently world-wide against the development of more dams whilst proponents are convinced tluit the y are a necessary feature to support growth and prosperity. It is these contradicting beliefs in mind tluit the public must be engaged to facilitate a better understanding of the views of both the proponents and the opponents of dam development before deciding on a long-term strateg y. In the meantime, more effort may have to be made for water and energ y conservation strategies and to realize the potential applications of low impact and non-structural solutions that complement existing dams and defer new dam development to as far into the future as possible.This paper aims to provoke a critical debate amongst engineers and the public to look at the longer term future ofdams in water resources development that could possibl y reduce the fundamental demand for services that dam provides. In other words, to try and answer the question “Why should a country rich in water, as Malaysia is, need to construct dams and even plan for more?”


2021 ◽  
Vol 894 (1) ◽  
pp. 012045
Author(s):  
A Sarminingsih ◽  
M Hadiwidodo

Abstract The planning of a flood control system in Indonesia is based on the planning criteria issued by the Ministry of Public Works. Flood control planning is based on flood discharge with a specific return period depending on the order of the river and the number of protected populations. Flood events in areas where the flood control system has been planned continue to occur almost every year, meaning that the probability of being exceeded is not as planned. This study is intended to evaluate the criteria for the magnitude of the designed flood discharge in flood control planning that considers the acceptable risk. Potential risks are evaluated against system reliability. The probability of failure of the flood control system occurs if the resistance is smaller than the load expressed as a performance function. By knowing the performance function associated with the level of flood risk, then the flood discharge can be selected with the appropriate return period according to the acceptable risk.


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