scholarly journals Identification of Manning’s Coefficient Using HEC-RAS Model: Upstream Al-Amarah Barrage

2020 ◽  
Vol 2020 ◽  
pp. 1-7 ◽  
Author(s):  
Sarmad A. Abbas ◽  
Ali H. Al-Aboodi ◽  
Husham T. Ibrahim
Keyword(s):  
Simulation Models ◽  
River System ◽  
Water Levels ◽  
Roughness Coefficient ◽  
Hydraulic Simulation ◽  
Tigris River ◽  
A Value ◽  
Manning’S Coefficient ◽  
South Of Iraq ◽  
Acceptable Agreement

In understanding the hydraulic characteristics of river system flow, the hydraulic simulation models are essential tools. This study submits the results of the proposition of a hydraulic model in order to determine the roughness coefficient (Manning’s coefficient n) of the Tigris River along 3.5 km within the Maysan Governorate, south of Iraq. HEC-RAS software was the simulation tool used in this study. The HEC-RAS model was adopted, calibrated, and validated in adopting two sets of observed water levels. Graphical and statistical approaches were used for model calibration and verification. Results from this investigation showed that a value of Manning’s coefficient of 0.025 gave an acceptable agreement between observed and simulated values of water levels.

scholarly journals Flow Characteristics Of Tigris River Within Baghdad City During Drought

2020 ◽  
Vol 26 (3) ◽  
pp. 77-92
Author(s):  
Bushra I Asaad ◽  
Basim Sh. Abed
Keyword(s):  
Water Supply ◽  
Flow Characteristics ◽  
Water Levels ◽  
Roughness Coefficient ◽  
Observation Data ◽  
Proper Solution ◽  
Easy Method ◽  
The North ◽  
Tigris River ◽  
High Level

The main source of water supply in Iraq is the surface water, especially Tigris and Euphrates Rivers and their tributaries. In the recent years there was a great drop in the water levels of Tigris River within Baghdad City which had affected the operation of twelve water supply projects located on the banks of Tigris River in Baghdad City, due to significant climate changes, and the expansion of hydraulic construction (dams) and implementation of new irrigation projects in Turkey, these factors have greatly reduced the water flowrates of river by about 46%. In the present study the flow characteristics of Tigris River within Baghdad City was studied, the reach involved was about 49km in which it represents the urban zone beginning from the north of the Baghdad City at Al-Muthana Bridge to the confluence of Tigris River with the Diyala River south of Baghdad, using steady flow one-dimensional hydraulic model to achieve raising of water levels within this reach during drought periods. This model was implemented using HEC-RAS software.Three sets of observation data were used to calibrate the model to estimate suitable Manning roughness coefficient (n) considering the root mean square error (RSME) as an accurate indicator. The results showed that n of value 0.032 for the main river bed and 0.040 for flood banks of the river gave the best results with minimum RMSE of 0.076. Several treatments were suggested such as construction of barrage, inflatable weir, and the use of obstruction for the purpose of raising water levels. Moreover, selection of the suitable site of these treatments or hydraulic structures was studied, as well as their cost was analyzed. The results show that the proper solution for maintain the required water levels that ensure continuous operation of water supply project was the construction of an inflatable weirs, due to low initial cost, simplicity of operation, their ability to inflate and deflate quickly and easily to prevent upstream flooding, and offering a high level of control and easy method for recapturing water.

scholarly journals Study and evaluation the Marshes and surrounding areas in south of Iraq

2020 ◽  
Vol 150 ◽  
pp. 03011
Author(s):  
Husam Al-Nussairi ◽  
Khalida Hassan
Keyword(s):  
Land Degradation ◽  
Agricultural Production ◽  
Drainage Water ◽  
Soil Productivity ◽  
Hydrochemical Characteristics ◽  
Drainage Systems ◽  
Tigris River ◽  
South Of Iraq ◽  
Surrounding Areas ◽  
Southern Iraq

In this study, the marshlands in southern Iraq were investigated, focusing on the Hawizeh Marshlands and adjacent areas, by studying the scenario and quantities of water, in addition to the hydraulic and hydrochemical characteristics. To accomplish the objects of this study the researcher visited some fields, made interview with farmers, specialists, authorities and directorates related to this study. The results of this study indicate that there are a huge problem existed in the drainage systems with absence of natural outlets, the discharges of drainage water is towards Al- Hawizeh marsh which flow back its water into Tigris river through several canals, increasing salinity, scare of water, miss-use of land, lack of governments efforts to promote agricultural production leads to loss of soil productivity and land degradation.

scholarly journals DEVELOPMENT OF A FLOOD RISK ASSESSMENT MODEL FOR A BRAIDED RIVER SYSTEM

2017 ◽  
pp. 25
Author(s):  
Mustafa Kemal Cambazoglu ◽  
Cheryl Ann Blain
Keyword(s):  
Risk Management ◽  
Flood Risk ◽  
Channel Model ◽  
River System ◽  
Flood Risk Management ◽  
High Flow ◽  
Water Levels ◽  
Pearl River ◽  
Braided River ◽  
River Channels

The aim of this study is to construct a modeling system that will assist flood risk management strategies in a coastal plain braided river system. The model configuration consists of a hydrodynamic model (ADCIRC) of the river basin that receives tidal forcing at the open boundary and river discharge forcing at upstream flux boundary. An unstructured mesh model resolving the Pearl River channels at higher resolution from the coastline to approximately 75km inland to upstream reaches of the river has been constructed. The modeling system produces water levels and currents throughout the Lower Pearl River Basin. Initial sensitivity analysis efforts on the channel model include consideration of low-flow, average-flow, and high-flow scenarios. Model results were found to be slightly sensitive to slope of river channels and bottom friction to control stability in predictions. The model results were shown to be highly sensitive to the bathymetry of the model that controls the discharge capacity of the narrow river channels and the channel model resulted in elevated currents and water levels under high flow conditions. A channel discharge capacity analysis was conducted and the results showed the need to construct a floodplain mesh around the channel model with more realistic bathymetry and topography so that the flooding scenarios could be modeled with wetting and drying capability of ADCIRC. An initial attempt to develop such a floodplain mesh has been made with preliminary results and more comprehensive validation of the developed floodplain modeling system will extend to reproducing events associated with the historical Hurricane Isaac that impacted the region in 2012. This modeling system will provide an important tool to decision makers that could be used in future flood risk management and mitigation efforts.

scholarly journals Feedback Mechanism in Bifurcating River Systems: the Effect on Water-Level Sensitivity

Water ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1915
Author(s):  
Matthijs R.A. Gensen ◽  
Jord J. Warmink ◽  
Fredrik Huthoff ◽  
Suzanne J.M.H. Hulscher
Keyword(s):  
Water Level ◽  
Flood Risk ◽  
River System ◽  
Feedback Mechanism ◽  
Water Levels ◽  
River Systems ◽  
Water Level Variations ◽  
System Water ◽  
Discharge Distribution ◽  
Single Branch

Accurate and reliable estimates of water levels are essential to assess flood risk in river systems. In current practice, uncertainties involved and the sensitivity of water levels to these uncertainties are studied in single-branch rivers, while many rivers in deltas consist of multiple distributaries. In a bifurcating river, a feedback mechanism exists between the downstream water levels and the discharge distribution at the bifurcation. This paper aims to quantify the sensitivity of water levels to main channel roughness in a bifurcating river system. Water levels are modelled for various roughness scenarios under a wide range of discharge conditions using a one-dimensional hydraulic model. The results show that the feedback mechanism reduces the sensitivity of water levels to local changes of roughness in comparison to the single-branch river. However, in the smaller branches of the system, water-level variations induced by the changes in discharge distribution can exceed the water-level variations of the single-branch river. Therefore, water levels throughout the entire system are dominated by the conditions in the largest branch. As the feedback mechanism is important, the river system should be considered as one interconnected system in river maintenance of rivers, flood-risk analyses, and future planning of river engineering works.

Modelling the Pathways of Toxic Contaminants in the St. Clair-Detroit River System Using the Toxfate Model: The Fate of Perchloroethylene

1986 ◽  
Vol 21 (3) ◽  
pp. 411-421 ◽  
Author(s):  
Efraim Halfon
Keyword(s):  
Half Life ◽  
Lake Erie ◽  
River System ◽  
High Water ◽  
Water Levels ◽  
Water Soluble ◽  
Detroit River ◽  
Wind Speeds ◽  
High Volatility ◽  
Local Water

Abstract Perchloroethylene (PERC) is a heavier-than-water, soluble and volatile solvent used primarily in the dry cleaning business. Black puddles (popularly known the the “blob”), containing several contaminants inducing PERC, were reported in the St. Clair River bottom sediments downstream from Sarnia in 1984 and in 1985. The TOXFATE model is used to predict the fate of PERC and the relative importance of volatilization in relation to water transport. Simulations show that in the St. Clair-Detroit River system about 82% (78-87%). under a variety of temperature and wind conditions) of the PERC loading is volatilized, about 17% (12-21%) of loading enters Lake Erie (more in winter, less in summer) and only about 1% remains in the system. The residence half life of PERC being transported in the water from Sarnia to Lake Erie is 350-400 hours and the half life of PERC being volatilized is 80-85 hours. A sensitivity analysis shows the importance of knowing the daily loadings to compute, in real time, local water concentrations following a PERC spill. The high water levels in the St. Clair River system do not influence the fate of PERC. Given the high volatility of PERC low temperatures and wind speeds do not reduce significantly the rate of removal of PERC from the system through volatilize nation.

scholarly journals Status of the Indus River dolphin Platanista minor

Oryx ◽  
1998 ◽  
Vol 32 (1) ◽  
pp. 35-44 ◽  
Author(s):  
Randall R. Reeves ◽  
Abdul Aleem Chaudhry
Keyword(s):  
Biological Diversity ◽  
Industrial Effluent ◽  
River System ◽  
Agricultural Runoff ◽  
Water Levels ◽  
Rapid Decline ◽  
Indus River ◽  
Effective Population ◽  
Urban Sewage ◽  
The Face

The endemic freshwater dolphins in the Indus River system of Pakistan, Platanista minor, have been considered endangered since the early 1970s. Measures taken to protect them from deliberate capture seem to have stopped a rapid decline, and combined counts in Sindh and Punjab provinces since the early 1980s suggest a total population of at least a few hundred animals. Severe problems remain, however. In addition to the risks inherent to any species with an effective population size in the low hundreds (at most), these dolphins are subject to long-term threats associated with living in an artificially controlled waterway used intensively by humans. Irrigation barrages partition the aggregate population into discrete subpopulations for much of the year. Dolphins that ‘escape’ during the flood season into irrigation canals or into reaches downstream of barrages where winter water levels are low have little chance of survival. A few dolphins probably die each year after being caught in fishing nets. Pollution by untreated urban sewage, agricultural runoff and industrial effluent threatens the health of the entire Indus system. The future of this dolphin species depends on Pakistan's commitment to protecting biological diversity in the face of escalating human demands on dwindling resources.

scholarly journals Simulation of flood flow in a river system using artificial neural networks

2005 ◽  
Vol 9 (4) ◽  
pp. 313-321 ◽  
Author(s):  
R. R. Shrestha ◽  
S. Theobald ◽  
F. Nestmann
Keyword(s):  
Neural Networks ◽  
Artificial Neural Networks ◽  
Flow Simulation ◽  
Simulation Models ◽  
River System ◽  
Training Data ◽  
Data Sets ◽  
Network Training ◽  
Artificial Neural ◽  
Flood Flow

Abstract. Artificial neural networks (ANNs) provide a quick and flexible means of developing flood flow simulation models. An important criterion for the wider applicability of the ANNs is the ability to generalise the events outside the range of training data sets. With respect to flood flow simulation, the ability to extrapolate beyond the range of calibrated data sets is of crucial importance. This study explores methods for improving generalisation of the ANNs using three different flood events data sets from the Neckar River in Germany. An ANN-based model is formulated to simulate flows at certain locations in the river reach, based on the flows at upstream locations. Network training data sets consist of time series of flows from observation stations. Simulated flows from a one-dimensional hydrodynamic numerical model are integrated for network training and validation, at a river section where no measurements are available. Network structures with different activation functions are considered for improving generalisation. The training algorithm involved backpropagation with the Levenberg-Marquardt approximation. The ability of the trained networks to extrapolate is assessed using flow data beyond the range of the training data sets. The results of this study indicate that the ANN in a suitable configuration can extend forecasting capability to a certain extent beyond the range of calibrated data sets.

scholarly journals Possibility of reusing Al-Machraya River for feeding Hawizeh marsh

2018 ◽  
Vol 162 ◽  
pp. 03004 ◽  
Author(s):  
Mahmoud Al-Khafaji ◽  
Hayder Al Thamiry ◽  
Ala Al-Saedi
Keyword(s):  
Water Level ◽  
Distribution Patterns ◽  
Water Levels ◽  
Type I ◽  
Normal Type ◽  
Distribution Models ◽  
Type Iii ◽  
Tigris River ◽  
Pearson Type ◽  
Log Normal

Al Machraya River was considered as one of the water feeders of Hawizeh Marsh. In 1986, the outlet of this river into the marsh was blocked and the river was used as a main channel for the East Tigris Irrigation Project near Kalat Salih. This causes significant decrease in the available water supply sources, deterioration in the water quality distribution patterns and increasing the stagnation areas within the marsh. This research aims to study the possibility of reusing this river for feeding Hawizeh Marsh. A frequency analysis study was carried out to study the maximum and minimum probable water level (MMPWL) of Tigris River at the upstream of Kalat Salih Barrage. Six statistical models; Normal distribution, Log-Normal type II, Log-Normal type III, Pearson type III, Log- Pearson type III and Gumbel type I distribution were used to estimate the MMPWL. The results show that Pearson type III and Gumbel type I distribution models are the best to fit the maximum and minimum daily water level (WL), respectively, at the upstream of the Barrage. The estimated MMPWL were compared to the required WL in Hawizeh Marsh. The difference between Tigris River and Hawizeh Marsh water levels were found to be not operative to cause a significant flow toward the marsh. Therefore, Al Machraya River cannot be used to feed Hawizeh Marsh.

scholarly journals Parameterization of Offline and Online Hydraulic Simulation Models

2015 ◽  
Vol 119 ◽  
pp. 545-553 ◽  
Author(s):  
Jochen Deuerlein ◽  
Olivier Piller ◽  
Idel Montalvo Arango ◽  
Mathias Braun
Keyword(s):  
Simulation Models ◽  
Hydraulic Simulation

The hydrologic regime of Mackenzie River and connection of "no-closure" lakes to distributary channels in the Mackenzie Delta, Northwest Territories

1995 ◽  
Vol 32 (7) ◽  
pp. 926-937 ◽  
Author(s):  
C. R. Burn
Keyword(s):  
Water Level ◽  
Drainage Basin ◽  
Late Summer ◽  
River System ◽  
Water Levels ◽  
Ice Thickness ◽  
Mackenzie Delta ◽  
Lake Ice ◽  
Discharge System ◽  
Mackenzie River

Mackenzie Delta lakes have been classified by the seasonal duration of their connection to Mackenzie River. "No-closure" lakes are determined on the basis of minimum summer water level. Such lakes may become disconnected from the Mackenzie in autumn or winter, as water level falls or if the sills between lakes and distributary channels are frozen through and so sealed. Water level in the central delta rises continuously after late November–early December, at first because discharge into the delta increases once the Mackenzie drainage basin has frozen over, and then as sea and channel ice thickens in the outer delta, impounding discharge. Since 1973 this seasonal increase in stage from its minimum in early December to the level on 1 April has been between 29 and 95 cm. Between 1987 and 1994, the rise in stage near Inuvik has been slightly greater than increases in lake-ice thickness (30–68 cm). Channels and lakes that are connected to the Mackenzie discharge system in December may remain connected throughout winter. A critical sill elevation for connection of such lakes to the river system is the minimum stage minus mid-December ice thickness. Recently, these elevations have been from 1.0 to 1.6 m lower than late summer water levels. Lakes with sill elevations still lower may remain connected to the Mackenzie throughout the year. In 1993-1994, only 3 of 16 "no-closure" lakes surveyed near Inuvik remained open to the Mackenzie discharge throughout winter, representing 2% of the lakes in this portion of the delta.

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