A Geomorphic Approach to the Design of Pipeline Crossings of Mountain Streams

2004 ◽  
Author(s):  
Matthias Jakob ◽  
Michael Porter ◽  
K. Wayne Savigny ◽  
Eugene Yaremko
Keyword(s):  
Return Period ◽  
Debris Flows ◽  
Peak Discharge ◽  
Hydrological Processes ◽  
Mountain Streams ◽  
Design Flood ◽  
Fluvial Process ◽  
Flood Discharge ◽  
Outburst Floods ◽  
Pipeline Crossing

Several hydrological methods are available to determine flood discharge and scour of streams at pipeline crossings. These methods are appropriate for streams dominated by purely hydrological processes, but fail where other, more hazardous processes occur within the design recurrence interval. Several investigations have shown that scour, impact and aggradation associated with debris flows, outburst floods or related phenomena may fundamentally change the parameters needed for proper pipeline crossing design. Depending on the process type, the peak discharge of the hazardous process can exceed that of the design flood (typically 50 to 200 year return period) by a factor of 2 to 50. Similarly, scour or aggradation by a non-fluvial process can exceed the hydrologically-derived estimates by several factors. It is therefore recommended that a geomorphic approach be taken in recognizing and quantifying the potential for non-fluvial processes and that the findings be integrated in the design of pipeline crossings.

scholarly journals ANALISIS BANJIR DAN TINGGI MUKA AIR PADA RUAS SUNGAI CILIWUNG STA 7+646 s/d STA 15+049

2018 ◽  
Vol 7 (1) ◽  
pp. 43-49
Author(s):  
Redaksi Tim Jurnal
Keyword(s):  
Frequency Analysis ◽  
Return Period ◽  
Synthetic Data ◽  
Gumbel Distribution ◽  
Peak Discharge ◽  
Design Flood ◽  
Distribution Method ◽  
Flood Peak ◽  
Method Of Calculation ◽  
Flood Discharge

The problem of flooding in DKI Jakarta is considered normal because almost every year can hit the city of Jakarta especially during the rainy season. In DKI Jakarta itself there are several rivers, one of which is Ciliwung River which is the most influential river in DKI Jakarta which often cause flood every year. The purpose of this research is to know the location of flood / river flood that occurs in the segments along Ciliwung River STA 7 + 646 s / d STA 15 + 049. Data processing begins with the calculation of average rainfall, frequency analysis, and then hour-time rain distribution. Method of calculation of flood discharge using the synthetic unit of Nakayasu and Gama I synthetic data. Rainfall data using 2 observation stations for 3 years rain (2014-2016). In the frequency analysis used Gumbel distribution berdasrkan test results suitability data Smirnov- Kolmogorov and Chi-Square. The result of flood peak discharge design with HSS Nakayasu on return period Q5 = 687,80 m3 / dt, Q10 = 743,21 m3 / dt, Q20 = 796,36 m3 / s, Q50 = 865,15 m3 / dt, Q100 = 916,71 m3 / s, while flood peak discharge design with HSS Gama I on return period Q5 = 347,03 m3 / s, Q10 = 372,12 m3 / s, Q20 = 396,20 m3 / s, Q50 = 427, 36 m3 / s, Q100 = 450,71 m3 / s. The design flood discharge value approaching the measured debit value is HSS Nakayasu. Steps continued using HEC-RAS 4.1.0 software to determine the capacity of river catchment by using Nakayasu discharge. After analyzing using the software, most stationing of the Ciliwung River at STA 7 + 646 to STA 15 + 049 can not accommodate the planned discharge during the 20th anniversary period, hence the need for river improvements in the form of river normalization and elevation of dikes.

scholarly journals PERBANDINGAN BEBERAPA METODE DEBIT PUNCAK BANJIR RANCANGAN COMPARISON OF SOME PEAK DISCHARGE FLOOD DESIGN METHODS

GANEC SWARA ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 526
Author(s):  
HUMAIROH SAIDAH ◽  
ATAS PRACOYO ◽  
KHAIRUDIN KHAIRUDIN
Keyword(s):  
Design Method ◽  
Water Discharge ◽  
Peak Discharge ◽  
Design Flood ◽  
Flood Peak ◽  
Accuracy Test ◽  
Flood Discharge ◽  
Proper Design ◽  
Design Calculations ◽  
Selection Of

Peak discharge flood analysis is very crucial in waterworks design. The proper design flood discharge will produce effective construction dimensions as project requirement. Therefore, flood design calculations must be analyzed using appropriate methods. The problem in estimating design flood discharge is usually found in ungauged watersheds which do not have any water discharge measuring equipment.This study wants to test the flood design method using rain data input to be applied to the Babak River, so the result can be used as a guide in the selection of flood discharge calculation techniques in other ungauged watersheds.The accuracy test is carried out by comparing the results of these methods with the flood design resulted from a frequency analysis of the Annual Maximum Series. Based on the results of the calculation, the peak flood of the Harpers method has the smallest RE and RMSEP values are 8.960% and 88.546 respectively. Thus, it can be concluded that the calculation of the design of the flood peak Haspers method has the best accuracy of the analysis results when compared with the Melchior and Weduwen methods for Babak River.

scholarly journals Design Flood Discharge of 50 Years in Garang River Using Nakasayu Synthetic Unit Hydrograph Method

2020 ◽  
Vol 22 (2) ◽  
pp. 146-151
Author(s):  
Nadya Kintantrie Maulana ◽  
Yeri Sutopo
Keyword(s):  
Return Period ◽  
Water Structure ◽  
Structure Design ◽  
Unit Hydrograph ◽  
Design Flood ◽  
Careful Planning ◽  
The Past ◽  
Central Java ◽  
Flood Discharge ◽  
Synthetic Unit Hydrograph

Abstract: Various kinds of buildings in civil engineering require careful planning. For example, in the planning of a water building needed a method to calculate the design flood discharge before starting to plan the dimensions of the building to meet the effectiveness of the water structure. Design flood discharge can be determined using several hydrograph methods that have been used in water building planning in Indonesia. One of the popular hydrograph method used is the Nakayasu Synthetic Unit Hydrograph method. In this case, the design flood discharge is located in the Garang watershed, precisely in Semarang City, province of Central Java, using rainfall data for the past 16 years. Hydrological analysis is carried out first before determining the design flood discharge with a return period of 2, 5, 10, 25, and 50 years. The results of the design flood discharge using Nakayasu method respectively were 305,522 m3/s, 390,742 m3/s, 447,783 m3/s, 520,560 m3/s, and 574,912 m3/s.

scholarly journals ECODRAINAGE SYSTEM EVALUATION AND CONTROL OF FLOODS IN JOMBANG DISTRICT, EAST JAVA

2021 ◽  
Vol 1 (2) ◽  
pp. 83
Author(s):  
Sri Rahmawati ◽  
Anita Rahmawati ◽  
Azizah Rachmawati
Keyword(s):  
Land Use ◽  
Return Period ◽  
System Evaluation ◽  
Design Flood ◽  
Populated Area ◽  
Type Iii ◽  
Flood Discharge ◽  
Design Rainfall ◽  
And Control ◽  
Green Land

Jombang sub-district is the most densely populated sub-district because it is located in the middle of Jombang district and is also the center of government. Because it is a densely populated area, resulting in many changes in land use, green land for absorption has turned into a watertight area. The results of the analysis from this aspect indicate that several channels in Jombang District are not able to accommodate the design flood discharge. The calculation of the height of rain design in this study used the Log Person type III method with a return period of 5 years, which resulted in the design rainfall of 157 mm. The results of the analysis show that there are 8 channels out of 74 that are unable to accommodate the design flood discharge. After planning the infiltration wells, a different number was obtained for each road. For Jalan Sentot Prawirodirjo, there are 8 infiltration wells with a reduction power of 51.62%.

scholarly journals Flood Inundation Prediction of Logung River due to the Break of Logung Dam

2017 ◽  
Vol 3 (2) ◽  
pp. 331 ◽  
Author(s):  
Listyo Rini Ekaningtyas
Keyword(s):  
Return Period ◽  
Flood Hazard ◽  
Maximum Velocity ◽  
Dam Break ◽  
Peak Discharge ◽  
Design Flood ◽  
Channel Routing ◽  
Inundation Area ◽  
Probable Maximum Flood ◽  
Simulation Results

The construction of Logung Dam in Kudus Regency is aimed to reduce the inundation area at downstream of Logung River, particularly during the rainy season. Besides, the potential water of Logung Dam is used for for irrigation and non-irrigation services. In order to mitigate the flood disaster that may arise in the downstream area, various preparedness should be established including the identification of flood hazard characteristics that may be caused by the break of the Logung Dam. This paper presents the results of Logung Dam break analysis using the levee pool routing model and the 2-D channel routing of the HEC-RAS 5.0 Version software. The initial value of breach parameter was calculated using the Froehlich’s equation, and variation of breaking times (1, 2, and 3 hours) were applied to study the generated hydrograph based on the corresponding elevation-storage curve. Furthermore, the simulation of channel routing at downstream of the dam was carried out in three different scenarios based on the bridges condition at downstream of the Logung Dam. Scenario 1 assumed that bridges will be safe enough against flood. Scenario 2 assumed that the bridges would only be safe at flood with return period lower than 20 years, whereas the scenario 3 assumed that bridges would be collapsed due to the flood at design flood with several return periods. The simulation results showed that the Probable Maximum Flood (PMF) with peak discharge of 1,303.60 m3/s did not generate overtopping. The peak discharge through the dam body was 15,022 m3/s at the first 40 minutes. It took 7 hours and 30 minutes to decrease the water level of the reservoir from +95.2 m to +38 m. In scenario 2, the simulation used 20 years return period flood with velocity in cross section before the Bridge RS 3700 was 7.21 m/s and before Bridge RS 6800 was 5.72 m/s. Furthermore, the 2-D simulation results showed that at the near downstream of the Logung Dam, the maximum depth was 55 m and the maximum velocity was 39 m/s. Several prone areas to flood caused by the dam break are the villages at the left side of the downstream Logung River including Bulung Cangkring, Bulung Kulon, Sidomulyo, Pladen and Jekulo village.

Design flood estimates in mountain streams – the need for a geomorphic approach

2001 ◽  
Vol 28 (3) ◽  
pp. 425-439 ◽  
Author(s):  
Matthias Jakob ◽  
Peter Jordan
Keyword(s):  
Debris Flows ◽  
Regional Analysis ◽  
Landslide Dam ◽  
Flood Frequency ◽  
Flood Hazards ◽  
Design Flood ◽  
Rainfall Frequency ◽  
Outburst Floods ◽  
Streamflow Data ◽  
Geomorphic Processes

Estimates of design flood frequencies are routinely required for engineering purposes on ungauged streams and streams with a limited period of streamflow record. In these cases, the design flood is determined either by rainfall frequency–duration analysis, regional analysis of streamflow data, or by extrapolation of a short record from a gauged stream. Although these types of analyses are valuable in a first approximation of peak discharges for different return periods, there is increasing evidence that geomorphic processes such as debris flows, landslide dam failures, glacial outburst floods, and even snow avalanches in the watershed can significantly exceed these estimates. This paper highlights the problem of a purely hydrologic approach for design flood estimates using several case studies, and suggests procedures to routinely include geomorphic processes in standard flood frequency studies.Key words: debris flows, debris floods, landslide dams, flood hazards, outburst floods, frequency analysis.

The Influence of Geographical Factors on Extreme Rainfalls in Lampung Province

2019 ◽  
Vol 1 (1) ◽  
pp. 33
Author(s):  
M Welly
Keyword(s):  
Geographical Location ◽  
Daily Rainfall ◽  
Extreme Rainfall ◽  
Design Flood ◽  
Extreme Rainfall Events ◽  
Rainfall Events ◽  
Ungauged Basin ◽  
Flood Discharge ◽  
Design Rainfall ◽  
Geographical Factors

Many people in Indonesia calculate design rainfall before calculating the design flooddischarge. The design rainfall with a certain return period will eventually be convertedinto a design flood discharge by combining it with the characteristics of the watershed.However, the lack of a network of rainfall recording stations makes many areas that arenot hydrologically measured (ungauged basin), so it is quite difficult to know thecharacteristics of rain in the area concerned. This study aims to analyze thecharacteristics of design rainfall in Lampung Province. The focus of the analysis is toinvestigate whether geographical factors influence the design rainfall that occurs in theparticular area. The data used in this study is daily rainfall data from 15 rainfallrecording stations spread in Lampung Province. The method of frequency analysis usedin this study is the Gumbel method. The research shows that the geographical location ofan area does not have significant effect on extreme rainfall events. The effect of risingearth temperatures due to natural exploitation by humans tends to be stronger as a causeof extreme events such as extreme rainfall.Keywords: Influence, geographical, factors, extreme, rainfall.

scholarly journals Analysis on the Return Period of “7.26” Rainstorm and Flood in 2017 in the Wudinghe Basin

2018 ◽  
Vol 246 ◽  
pp. 01105
Author(s):  
Shuang-yan Jin ◽  
Wen-yong Gao ◽  
Si-wu Luo ◽  
Ya-jun Gao
Keyword(s):  
Return Period ◽  
Peak Discharge ◽  
Observation Data ◽  
Historical Survey ◽  
Annual Maximum ◽  
Frequency Curve ◽  
Recurrence Period ◽  
Fitting Method ◽  
Curve Fitting Method ◽  
Hydrological Station

The return period of "7.26" rainstorm flood in 2017 in Wudinghe basin is analyzed by the method of P-III distribution. The Lijiahe and Dingjiagou stations with long rainfall observation data in the rainstorm area are selected, and the frequency curve of the annual maximum 24 hours rainfall are established, and the recurrence period of rainfall stations in rainstorm area are estimated according to the parameters determined by the curve fitting method. The frequency curve of the annual maximum peak discharge of Baijiachuan hydrological stations and so on are established, and the return period are analyzed in combination with the historical survey floods. The results show that the return period of Zhaojiabian of heavy rainfall center is about 100 years, and which of the other stations over than 200mm in Wudinghe basin is about 30~90 years; while the return period of the peak discharge of Baijiachuan and Suide hydrological station is about 30 and 20 years respectively.

Debris Flows Resulting From Glacial-Lake Outburst Floods in Tibet, China

2010 ◽  
Vol 31 (6) ◽  
pp. 508-527 ◽  
Author(s):  
Peng Cui ◽  
Chao Dang ◽  
Zunlan Cheng ◽  
Kevin M. Scott
Keyword(s):  
Debris Flows ◽  
Glacial Lake ◽  
Outburst Floods ◽  
Glacial Lake Outburst Floods
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