Response of flood discharge capacity to the channel boundary and upstream conditions in a braided reach

2020 ◽  
pp. 2188-2195
Author(s):  
Yifei Cheng ◽  
Junqiang Xia* ◽  
Shanshan Deng ◽  
Meirong Zhou
Keyword(s):  
Discharge Capacity ◽  
Flood Discharge ◽  
Channel Boundary ◽  
Braided Reach

scholarly journals Evaluation of Dimensions and Drainage Performance Office in the Aceh Tamiang Area Kuala Simpang

2021 ◽  
Vol 3 (1) ◽  
pp. 20-32
Author(s):  
Kamaluddin Lubis
Keyword(s):  
Channel Capacity ◽  
Discharge Capacity ◽  
Return Period ◽  
Rainfall Intensity ◽  
Drainage Channel ◽  
Flood Discharge ◽  
Discharge Plan ◽  
Runoff Discharge ◽  
High Degree

The Aceh Tamiang office area is one of the office areas in Kuala Simpang which consists of various offices in the Aceh Tamiang area. The purpose of this research is to identify the drainage condition of the existing primary drainage channel which accommodates runoff discharge, the shape and direction of the flow in the inundation channel in the Aceh Tamiang Kuala Simpang office area, which is expected to help solve the problem of flooding in the 832 m3 / second. And for the channel capacity in this primary drainage drainage of 0.829 m3 / sec, the value is smaller than the planned flood discharge (Qr). Rainfall intensity (I) of 126,432 mm / hour. The plan flood discharge (Qr) for a 5-year return period yields 2,551 m3 / second and the value for channel discharge capacity (Qs) is obtained from the calculation of 2,216 m3 / second. This value is smaller than the value of the planned flood discharge.area. From the results of research conducted by the Aceh Tamiang Kuala Simpang office area is a location with a fairly high degree of rainfall, with a rainfall intensity (I) of 126,432 mm / hour and a flood discharge plan for a 5-year return period obtained a result of 0.

scholarly journals Effect of Tail Regulators on Euphrates River Flood Capacity at Al Nassiriyah City

2019 ◽  
Vol 26 (1) ◽  
pp. 43-54
Author(s):  
Atheer Ghazi Shayea ◽  
Hayder A. Al Thamiry
Keyword(s):  
Discharge Capacity ◽  
Return Period ◽  
River System ◽  
Hydraulic Structures ◽  
Euphrates River ◽  
Flood Discharge ◽  
Maximum Discharge ◽  
River Flood ◽  
River Training ◽  
The Impact

Euphrates River extends about 125 km within the study area located in Annassiriyah City, Dhi Qar Governorate, Iraq. The impact of the seven hydraulic structures on the discharge capacity of the Euphrates River needs to be considered. The main objectives of this research are to increase the discharge capacity of Euphrates River within Annassiriyah City during flood seasons and study the impact of these hydraulic structures on the river capacity by using HEC-RAS 5.0.3 software. Five scenarios were simulated to study the different current condition of Euphrates River within Annassiriyah City. Other additional four scenarios were implemented through river training to increase the river capacity to 1300 m³/s; it is the flood of 100 year return period. The results of the current condition showed that the maximum discharge capacity of Euphrates River within Annassiriyah City is just 300 m³/s. The results of applied improvements show that the capacity can reach 1300 m³/s when Al Chibayish Weir was hypothetically removed from the river system. Additionally, the river capacity will be reduced to 600 m³/s when Al Chibayish Weir is considered. It was concluded that the 100-year flood discharge cannot be achieved without removing Al Chibayish Weir from the river system.

scholarly journals Current and Modified Flood Discharge Capacity of a Reach of Tigris River between Kut and Amarah Barrages

2020 ◽  
Vol 26 (2) ◽  
pp. 129-143
Author(s):  
Maysam S Abbas ◽  
Riyadh Z. Azzubaidi
Keyword(s):  
Cross Section ◽  
Discharge Capacity ◽  
Cross Sections ◽  
Flood Plain ◽  
Main Channel ◽  
Water Levels ◽  
Flood Wave ◽  
Tigris River ◽  
Flood Discharge ◽  
Lateral Inflow

This study was conducted to examine the discharge capacity of the reach of the Tigris River between Kut and Amarah Barrages of 250km in length. The examination includes simulation the current capacity of the reach by using HEC-RAS model. 247cross sections surveyed in 2012 were used in the simulation. The model was calibrated using observed discharges of 533, 800, 1025 and 3000m3/s discharged at Kut Barrage during 2013, 1995, 1995 and 1988, respectively, and its related water level at three gauge stations located along the reach. The result of calibration process indicated that the lowest Root Mean Square Error of 0.095 can be obtained when using Manning’s n coefficient of 0.026, 0.03 for the Kut- Ali Al Garbi and Ali Al Garbi- Amarah reaches respectively, and 0.03 for the flood plain of the whole reach under study. The reach under study has two lateral inflow streams, UmAljury, which joins Tigris River at station 51km, and Aljabab, which joins Tigris River at station 57km. The discharge of Aljabab varies between 0 and 400m3/s and the discharge of UmAljury varies between 0 and 50m3/s.                     The results showed that the current capacity of the main channel of the reach of the Tigris River between Kut and Amarah Barrages is 400m3/s. The water levels kept less 1m than both levees in case of discharging 1800m3/s from Kut Barrage, with no lateral inflows, and 1700m3/s with lateral inflow. The reach of Tigris River fails to accommodate the flood discharge of 3300m3/s which is the discharge of the flood of 1988 measured at Kut Barage. It can be concluded that the reach had large amount of sediment for the period from 1988 to 2012 and the reach capacity reduced to about half its capacity of 1988 during this period.                                                          The results of removing 12 islands and 2 sidebars by reshaping the current condition into trapezoidal cross-section will decrease the surface water levels by 20cm and flow of 1900m3/s can be discharged safely at Kut Barrage without any lateral inflow and 1800m3/s with lateral inflow from the tributaries. While, expand 58 narrow cross-sections that choking the flow, the water levels along the reach are lowered by an average of 20cm in addition to that 20cm when modifying the cross-sections at the islands and sidebars. In this case, flow of 2100m3/s can safely be discharged from Kut Barrage without any lateral inflow and 1900m3/s with lateral inflow. The result when modifying additional 111 cross-sections showed that the reach can safely accommodate a flood wave of 3300m3/s from Kut Barrage without any lateral inflow and 3000m3/s with lateral inflow.                                                                                                            

Study on Flood Discharge and Countermeasures of ShiQiao Reservoir Spillway

2012 ◽  
Vol 212-213 ◽  
pp. 699-704
Author(s):  
Xiao Qing Wang ◽  
Chang Wu Liu ◽  
Jing Hao Zeng
Keyword(s):  
Discharge Capacity ◽  
Flood Control ◽  
Engineering Geology ◽  
Agricultural Water ◽  
Safe Operation ◽  
Flood Discharge ◽  
The 1950S

The ShiQiao Reservoir was built in the 1950s, whose main functions are irrigation and flood control. With the increasing number of downstream agricultural water, the contradiction is increasingly prominent between pettier beneficial capacity and the raising downstream agricultural water; at the same time, due to the disrepair of spillway and the increase of upstream inflow, the original spillway flood discharge capacity cannot meet the requirements for flood control. On the basis of systematical investigations of engineering geology and hydrogeological, an effective method is proposed for plain reservoirs to solve these problems. The method is, by improving the weir crest elevation and widening spillway to address the inadequate of beneficial capacity and the low standard of flood control spillway. Through the validation of analysis and calculation, this method is feasible and economical. It fundamentally solves the problems of ShiQiao Reservoir, and ensures the safe operation of this reservoir.

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.

Integral modeling of MHD channel boundary layers

1980 ◽  
Author(s):  
J. GERTZ ◽  
T. OPAR ◽  
A. SOLBES ◽  
G. WEYL
Keyword(s):  
Boundary Layers ◽  
Channel Boundary ◽  
Mhd Channel
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