hydrogeology
Mirali Mohammadi; Mahsa Mohtadi
Abstract
The purpose of present research work is to study the hydraulic properties of River Simineh and its process using HEC-RAS model, in a combination with ArcGIS software using HEC-GeoRAS extension to simulate the hydraulic parameters of river having a catchment area of 3726 km2. For that mean, since multi-dimensional ...
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The purpose of present research work is to study the hydraulic properties of River Simineh and its process using HEC-RAS model, in a combination with ArcGIS software using HEC-GeoRAS extension to simulate the hydraulic parameters of river having a catchment area of 3726 km2. For that mean, since multi-dimensional models require long time and high cost in river bends, by using a combination of satellite images and HEC-RAS model a multi-dimensional simulation was prepared. Among those, 58 cross-sections are considered along the river lane that main data required in this research are elevation maps, satellite images, boundary conditions and River Simineh hydrometric stations. The results showed that at the upstream of river, the discharge was 316.3 m3/s and water level was 12.85 m, and at the downstream the flow rate and water level are 313.6 m3/s and 11.52 m, respectively. On the other side of the river bend, the water level variation is around 50 cm and the flow velocity is directly proportion to a distance from the river bank; so that the maximum flow velocity of 2.2 m/s occurred at a distance nearby 1.5 m. To verifying the model, a statistical parameter of NSE coefficient for the water level and flow depth were 0.805 and 0.845, respectively; which shows the accuracy of model. Those results indicate a high accuracy of HEC-RAS model in hydraulic simulation of River Simineh flow. Also, simulations prepared in GIS background have significant impacts on the accuracy of outputs
Morteza Samadian; Behzad Hessari; MirAli Mohammadi; Mohammad Taghi Alami
Abstract
1-Introduction River training, flood control projects and every changing of river geometry will change the morphology conditions of the river and hydraulic characteristics of the flow in the river. In fact, the goal of river training plans can be found on the basis of the initial energy equilibrium of ...
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1-Introduction River training, flood control projects and every changing of river geometry will change the morphology conditions of the river and hydraulic characteristics of the flow in the river. In fact, the goal of river training plans can be found on the basis of the initial energy equilibrium of the river. In this study, the impact of river training on the hydrodynamic conditions of Zarrineh River in conjunction with Shahindezh city in different scenarios were investigated. Zarrineh River training project modeling, as a general objective, is the use of hydraulic simulations to create a river water surface based on new physical, civil, and hydrological properties of a given reach. The motivations for conducting such simulations are flood plain extent mapping based on current and new scenarios and the determination of water level along the study river reach. The objective of this project is to create maps before and after a new river training plan, all within the GIS and Autocad environment with georefrenced origin. Study of Zarrineh river project requires a thorough evaluation of the possible impacts that it may have, both upstream and downstream from the Vahdat Bridge on Zarineh River. Prediction of the operation, maintenance, and repair or replacement of the bridge, requirements of existing and proposed projects are other roles that river hydraulics simulations play in the planning and design processes. Zarineh River is a very wild river and every civil project highly needed to be evaluated from different aspects especially new geomorphological conditions. New liberalized areas beside the river for each scenario should be determined and evaluated for new land use utilizing particularly for Eco-Tourism usages. Sharifi and Pernoun (2017 p. 59) emphasized that the dynamical power of the river in the upstream and flow forces reduction in the downstream have a significant effect in the geometry formation of the rivers. Niranjan et al., (2010) showed that the MIKE11HD model has been able to accurately estimate and simulate water level in Berahmani river. The simulated river surface profile from MIKE11HD was used to simulate protective structures behavior in the river. The performance of the MIKE11 model in the simulation of hydrologic-hydrodynamic processes of rivers were confirmed in other studies such as Guang et al. (2017), Uleke et al. (2017), Tran et al. (2018) and Kha et al. (2018). 2- Methodology MIKE11 was selected to simulate current and selected new river training scenarios that iteratively solves a one-dimensional energy balance to produce water elevations based on river geometry, channel roughness, flow rate and boundary conditions. MIKE11, developed by DHI, is a software package for simulating flows in rivers. The river geometry is provided in the form of channel cross-sections at regular intervals along the direction of flow. The number of cross sections that are taken varies with study requirements and stream characteristics. About 1 km reach of the upstream and downstream of existing Vahdat bridge with 14 cross sections under current situation (without bridges and without training), the bridge with 120 meters without training, the bridge with 120 m, 200 m and 300 m with bed and banks training. For the current and scenarios it is needed to predict stage, discharge, and velocity as functions of time anywhere on a river in different return periods such as 25 yr. To measure cross-sectional coordinates, previous topographic maps generated from field surveys performed with land surveying instruments were used. All information to set up the Mike model, including input data files, simulation period, time step and the name of result files and also initial and boundary conditions have been determined and defined. Flow hydrographs for the project at the bridge location for all scenarios, extracted from hydraulically simulations from Mike11. For Hydrograph prediction the Saint-Venant approach with Finite Element method and Six-Point Algorithm of Abbott used to discretized temporal and spatial elements. 3- Results and discussion Zarrineh river project consists of Vahdat Bridge that should be modelled and finally it should be cover reliability of new area liberalization without any impact to users of Shahindezh such as Municipality, regional water authority, Environmental protection agency and Ministry of Roads and City affairs. In river training scenario with widening bridge to 300 m, in addition of a liberalization of 90 ha areas on both sides of river banks, water level will be decreased about 65 cm and maximum flow capacity will be increased to 115000 m3. The calibration results indicate that the estimated error rate of flow volume (REV) and the relative error in the peak (REQP) for training scenario are 0.197 and 1.792% respectively that corresponding to current condition about 0.068 and 2.82 percent .This figures shows good agreement between modeled and observed values. Vahdat Bridge with 120 lengths with 1200 m3/sec (25 yr return flow) will overflow to adjacent areas. The modelling results show the high potential of river training on the flood transmitting and flood routing and also, the accuracy of the simulation of unsteady flow is one dimensional for the desired range by the MIKE11 mathematical model. 4- Conclusion The river training projects should be modelled, controlled, evaluated for overflow problem from sidewalls and also river bed and banks should be controlled that is not affected by water score problem. For secure hydrograph transmitting in the reach of Zarineh River and Shahindezh city conjunction, the 300-meter bridge widening scenario is selected and the executive maps and detailed plans for the river training, bridge with a width of 300 meters, sidewalls and end sill structure (river bed stabilizing structure for preventing score) were provided.
Mirali Mohammadi; Farnaz Mohammadi; Ahmad Fakherifard; Sajad Bijanvand
Abstract
1- Introduction Mainly the flood is caused by the surface runoff resulted from the properties of precipitation and river basin. The reduction of flooding by the effect of vegetation and soil in a small basin is less than a basin with a large area. Hence, to have a flood zoning map, the first step is ...
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1- Introduction Mainly the flood is caused by the surface runoff resulted from the properties of precipitation and river basin. The reduction of flooding by the effect of vegetation and soil in a small basin is less than a basin with a large area. Hence, to have a flood zoning map, the first step is studying economic flood management and flood control projects. This paper focuses on Baranduz-chay River as a case study, located in the Urmia lake basin. The river reach having 3 km long, was studied between two hydrology stations namely Bibakran at the upstream and Dizaj at the downstream. The annual peak discharge data of Baranduz-chay has surveyed during the years from 1974 to 2013, where the appropriate Manning roughness coefficient, n, by averaging 0.0325 as an upstream coefficient and 0.0301 as a downstream coefficient were both implemented in the HEC-RAS software and its result including floodplain zones elevation extraction by the Muskingum-Cunge method, based on the floods with different return periods obtained. After converting these zones to their corresponding risk for each return period time, it has been delineated in Arc-Map software through HEC-geo-RAS extension, floodplain zones were then defined. The maximum inundated area is 97.34 Hectares and belongs to 1000 years return period which has the most risk as 63.58% within 3 years of useful periods. The Rule Curve is obtained by inundated areas with both different return and useful periods from the risk formula in which the general Area-Period-Risk formula was extracted. Basically, the magnitude of the floods and their repetition over time is subject to rainfall intensity, permeability, and topographic conditions in the area. The occurrence of floods as one of the natural disasters that cause many financial losses in many parts of the world. The first step in economic studies of flood management or flood control is flood zoning. Flood zoning means the extent to which the flood covers the area. Today, via modern science and technology, human beings are trying to optimize designs and to reduce these costs. Therefore, it seems that flood zoning study in the permanent and seasonal rivers path appears to be of great importance by conducting case studies in vulnerable areas. ShahiriParsa et al. (2016: 55-62) used the integration of the HEC-RAS one-dimensional model and the two-dimensional CCHE2D model on the Sungai Maka river in the state of Kelanten, Malaysia. They concluded that in this case, some important factors are: Manning’s flow resistance coefficient, n, the geometric profile of the river section and the choice of the most suitable flood return period. The mentioned parameters have a major role in providing flood zoning outcome, which has caused the most changes in the geometric shape of the river section. Their results showed that the greatest difference between the models was 6% in the location of the meandering rivers. The results of both models were also consistent in most of the transverse sections, and, due to the difference in the shape of the rivers, the greatest difference was the difference between the two models. Sung et al. (2011: 1-12) used the Maskingum method to process unqualified basins by analyzing the HEC-HMS hydrologic model and the HEC-geo-HMS geo-hydrologic model, the extraction of sub-basins and characteristics of the basin was extracted. The results showed that the percentage of flood events proportional to the maximum discharge errors of a moment of less than 20% and a runoff volume of less than 10% to reaches 100%. 2- Methodology Baranduz-chay river as the main river and permanent water catchment area of the study area. It originates from the highlands of Iran and Turkey border. The catchment area of this riverside in Saatlu is about 666 square kilometers and in Babarood is 1012 square kilometers. This research was associated with a similar risk due to the risk relationship with different return periods for the restricted areas around the river, based on different return periods. To determine risk areas or certain return periods, peak discharges were fitted with the best statistical distribution and through that, peak discharges were then calculated with different return periods and each of them was determined along the river and its expansion area. 3- Results and discussionFig. 3, shows the risk versus area (A, RISK), the risk with a downward trend, which means that the area risk is decreasing with the area covered by the risk area. By fitting a variety of exponential, linear, logarithmic, polynomial and power statistical functions, among those functions as shown in Fig. 3, risks with different useful lives are plotted simultaneously and from among functions, the power function was selected as a suitable fit function in order to obtain the general probabilistic distribution function and its parameters based on different useful life. Fig. (3) Risk diagram versus area (Rule Curve) with a different useful life 4- Conclusions For the Manning roughness coefficient, n, in the hydraulic model, the Manning’s n for the upstream and downstream stations were computed. The roughness coefficients, n, were then obtained for the upstream and downstream stations as 0.0325 and 0.0301, respectively. In order to obtain the corresponding risks for the areas covered by a flood of 3 km long from the Baranduz-chay between the upstream Bibakaran station and the lower reaches of the Hoerl's model, which is a type of power function. The risk-space-period curve for the specified periods is 2, 3, 5, 10, 25, 35 and 75 years (for more details, see Mohammadi, 2016).
Morteza Samadian; Behzad Hessari; MirAli Mohammadi; Mohammad Taghi Alami
Volume 6, Issue 18 , June 2019, , Pages 161-180
Abstract
IntroductionRiver training, flood control projects, and every change of river geometry will change the morphological conditions of a river and the hydraulic characteristics and flow. In fact, the goal of river training plans can be found on the basis of the initial energy equilibrium of the river. In ...
Read More
IntroductionRiver training, flood control projects, and every change of river geometry will change the morphological conditions of a river and the hydraulic characteristics and flow. In fact, the goal of river training plans can be found on the basis of the initial energy equilibrium of the river. In this study, the impact of river training on the hydrodynamic conditions of the Zarrineh River in conjunction with Shahindezh city in different scenarios were investigated. The Zarrineh River training project modeling, as a general objective, is the use of hydraulic simulations to create a river water surface based on new physical, civil, and hydrological properties of a given reach. The motivations for conducting such simulations are flood plain extent mapping based on current and new scenarios and the determination of water level along the study river reach. The purpose of this project was to create maps before and after a new river training plan, all within the GIS and Autocad environment with a georefrenced origin. Study of the Zarrineh River project requires a thorough evaluation of the possible impacts that it may have on the Zarineh River, both upstream and downstream from the Vahdat Bridge. The prediction of the operation, maintenance, and repair or replacement of the bridge, requirements of existing and proposed projects are other roles that river hydraulics simulations play in the planning and design processes. The Zarineh River is a very wild river and every civil project is needed to be evaluated from different aspects, especially from new geomorphological conditions. New liberalized areas beside the river for each scenario should be determined and evaluated for new land use utilizing particularly for Eco-Tourism usagesand repair or replacement of the bridge, requirements of existing and proposed projects are other roles that river hydraulics simulations play in the planning and design processes. The Zarineh River is a very wild river and every civil project is needed to be evaluated from different aspects, especially from new geomorphological conditions. New liberalized areas beside the river for each scenario should be determined and evaluated for new land use utilizing particularly for Eco-Tourism usages. Material and methodMIKE11 was selected to simulate current and selected new river training scenarios that iteratively solve a one-dimensional energy balance to produce water elevations based on river geometry, channel roughness, flow rate, and boundary conditions. MIKE11, developed by DHI, is a software package for simulating flows in rivers. The river geometry is provided in the form of channel cross-sections at regular intervals along the direction of flow. The number of cross sections that are taken varies with study requirements and stream characteristics. About 1 km reach of the upstream and downstream includes Vahdat bridge with 14 cross sections under current situation (without bridges and without training), the bridge with 120 meters without training, the bridge with 120 m, 200 m and 300 m with bed and banks training. For the current scenarios, it is needed to predict stage, discharge, and velocity as functions of time anywhere on a river in different return periods such as 25 yr. To measure cross-sectional coordinates, previous topographic maps generated from field surveys performed with land surveying instruments were used. All information to set up the Mike model, including input data files, simulation period, time step and the name of result files and also initial and boundary conditions were determined and defined. Flow hydrographs for the project at the bridge location for all scenarios were extracted from hydraulical simulations Mike11. For Hydrograph prediction, the Saint-Venant approach with Finite Element method and Six-Point Algorithm of Abbott were used to discretize temporal and spatial elements.Results and DiscussionThe Zarrineh River project consists of Vahdat Bridge that should be modelled and it should be checked for the reliability of new area liberalization without any impact on users of Shahindezh such as municipality, regional water authority, environmental protection agency and ministry of roads and city affairs. In river training scenarios with widening bridge to 300 m, in addition to the liberalization of 90 ha areas on both sides of river banks, the water level increased about 65 cm and the maximum flow capacity increased to 115000 m3. The calibration results indicated that the estimated error rate of flow volume (REV) and the relative error in the peak (REQP) for training scenario were respectively 0.197 and 1.792%, corresponding to the current condition which were about 0.068 and 2.82 percent. The figures showed a good agreement between modeled and observed values. Vahdat Bridge with 120 lengths and 1200 m3/sec (25 yr return flow) will overflow to adjacent areas. The modelling results showed the high potential of the river training for the flood transmission and flood routing. Also, the accuracy of the simulation of unsteady flow is one dimensional for the desired range by the MIKE11 mathematical model.ConclusionThe rivertraining projects should be modelled, controlled, and evaluated for overflow problem from sidewalls. In addition, river bed and banks should be controlled so that they are not affected by water score problem. For secure hydrograph transmission in the reach of the Zarineh River and Shahindezh city conjunction, the 300 m bridge widening scenario was selected and the executive maps and detailed plans for the river training, bridge with a width of 300 meters, sidewalls and end sill structure (river bed stabilizing structure for preventing score) were provided.
