EGU 2020 Assessment of Flood Effect on Semi-Arid Special Investment Region using 1D Hydrodynamic Modeling
AUTHORS CO-AUTHORS Dr S M Yadav, Professor Dr. Shri Ram Chaurasia, Professor. Surendra Borana, PG Scholar MMMUT, Gorakhpur(India) CED,SVNIT,SURAT(India) Dr.Mrs. N.D.Jariwala, Assistant Professor CED, SVNIT, Surat (India)
AUSTRIA| 3 - 4 MAY 2020 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020 Contents • Introduction • Theoretical Background in MIKE HYDRO River • Study area, data required and collected • Development of 1D Hydrodynamic model • Results and proposed flood mitigation measures • Conclusions and Discussions
AUSTRIA| 3 - 4 MAY 2020 2 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
Introduction
AUSTRIA| 3 - 4 MAY 2020 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
● In search of better livelihood and lifestyle, every minute around 25 to 30 people are migrating to cities from rural area in India. If this pace of urban migration continues the urban population of India is likely to reach 600 million by the year 2030. (https://www.investindia.gov.in/team-india-blogs/india-preparing-biggest-human- migration-planet)
● To account for this immense stress on existing cities due to migration, India is in urgent need of new cities which ensure the better lifestyle and livelihood opportunities for the migrators.
AUSTRIA| 3 - 4 MAY 2020 4 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
● Fig. 1. Migration to urban centres in India (https://www.hindustantimes.com/analysis/migrants-aren-t-streaming-into-cities.html)
AUSTRIA| 3 - 4 MAY 2020 5 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
● The types of migrants ranges from highly skilled IT professionals to farm laborers having vision to seek better livelihood and lifestyle at the urban centers.
● These migrations highlighted the need for holistic planning, criticality of infrastructure – link development and availability of employment opportunities in the near vicinity.
AUSTRIA| 3 - 4 MAY 2020 6 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
● With this thought, Government of India launched the Delhi – Mumbai Industrial Corridor (DMIC) development project aiming to develop 24 new Industrial cities between the nation’s political capital (Delhi) and financial capital (Mumbai).
● As a part of Delhi – Mumbai Industrial Corridor (DMIC) project, Government of Gujarat aims to develop a largest investment node as Dholera Special Investment Region (DSIR).
● (https://www.investindia.gov.in/team-india-blogs/india-preparing-biggest-human- migration-planet)
AUSTRIA| 3 - 4 MAY 2020 7 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
● Fig. 2. Delhi Mumbai Industrial Corridor (https://dipp.gov.in/japan-plus/delhi- mumbai-industrial-corridor-dmic)
AUSTRIA| 3 - 4 MAY 2020 8 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
● Dholera Special Investment Region (DSIR) is a Greenfield Industrial City planned and located approximately 100 km South West of Ahmedabad.
● Total land area of DSIR is about 920 square kilometre (sq km) of which 520 sq km has been allocated for town planning and approximately 400 sq km falls under coastal regulation zone (CRZ) of Gulf of Khambhat.
● (http://dicdl.in/planning/?q=development_highlight)
AUSTRIA| 3 - 4 MAY 2020 9 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
● The proposed area principally comprises of mud flats with large parts under salt ingression from a network of intertidal channels connected to the Gulf of Khambhat.
● (http://www.gsdma.org/Content/flood-seismic-vulnerability-4206)
● The special investment region comprises of manufacturing areas, commercial areas, educational and skill development centers, banking and financial institutions, etc.
AUSTRIA| 3 - 4 MAY 2020 10 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
● The city will have smart and sustainable infrastructure spanning transportation, water, power, wastewater, drainage and urban design.
● By 2050, the city will have the capacity and resources to support a population of two million and provide employment for around 800,000 people.
● (https://aecom.com/projects/dholera-special-investment-region/)
AUSTRIA| 3 - 4 MAY 2020 11 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
● Fig. 3.Master plan & phase - wise development plan of DSIR Area (http://dicdl.in/planning/?q=development_highlight)
AUSTRIA| 3 - 4 MAY 2020 12 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
● DSIR is a delta region and is blessed by number of rivers starting from river Sukhbhadar in the north to Lilka, Utavali, and Padalio River at extreme south and local khadi (creek) namely Bhadar Creek, Vankol Creek, Bavaliyari Creek and Sonari Creek to Gulf of Cambay.
● Flooding is one of the natural calamity which can affect the DSIR as the terrain profile of DSIR is flat and low lying and is in the delta region of four rivers.
● (http://www.gsdma.org/Content/flood-seismic-vulnerability-4206)
AUSTRIA| 3 - 4 MAY 2020 13 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
● In the monsoon season, when there is heavy rainfall and high tide in the gulf of Cambay, the backwaters inundate the whole DSIR area for number days.
● (http://www.gsdma.org/Content/flood-seismic-vulnerability-4206)
AUSTRIA| 3 - 4 MAY 2020 14 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
Fig. 4.Photographs taken during the site visit from 1 Oct 2019 to 4 Oct 2019 AUSTRIA| 3 - 4 MAY 2020 15 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
Fig. 5.Photographs taken during the site visit from 1 Oct 2019 to 4 Oct 2019 AUSTRIA| 3 - 4 MAY 2020 16 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
● It is evident that the DSIR region is under considerable threat of flood hazards and when such huge investments is to be made in this region, it must be protected from flooding.
● To get a quantitative and qualitative judgement of the vulnerability of flooding in this region it is required to develop a hydrodynamic model of the region.
● In the present study MIKE HYDRO River software have been used for the development of Hydrodynamic model.
AUSTRIA| 3 - 4 MAY 2020 17 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
Theoretical background of MIKE HYDRO RIVER
AUSTRIA| 3 - 4 MAY 2020 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
● Saint - Venant Equation:
● One dimensional unsteady flow, represented by Saint-Venant equations, i.e. conservation and Non-conservation form of Continuity and Momentum equation can be expressed as
AUSTRIA| 3 - 4 MAY 2020 19 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
Where, 푥 = Longitudinal distance along the channel, 푡 = Time, 퐴 = Area along the cross section of flow, 푄 = Discharge along the channel, 푉 = Velocity of flow, 푦 = Water surface elevation, 푔 =
Gravitational acceleration, So =Bed slope, 푆f = Friction slope
AUSTRIA| 3 - 4 MAY 2020 20 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
● Kinematic wave model:
● This is the simplest distributed model, in this local acceleration, convective acceleration and pressure term in momentum equation is neglected.
● The friction force is equal to gravity force So = Sf.
● This model is not used for the backwater effect, applicable in steep rivers often used for the calculation of runoff or to get the initial condition.
AUSTRIA| 3 - 4 MAY 2020 21 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
● Diffusive wave model:
● Diffusive wave model incorporates the gravity force, friction force and pressure term but neglects the local as well as the convective acceleration.
● This model is used to deal with the slowly propagating flood wave and backwater effect.
AUSTRIA| 3 - 4 MAY 2020 22 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
● Full dynamic model:
● This model incorporates all the terms in the Saint-Venant equation.
● The equation is classified as the partial differential equation.
● The propagation of wave takes place in an upstream and downstream direction as well which depend on Froude no. for the 1D model, based on the full dynamic wave equations are like HEC- RAS, MIKE 11 etc.
AUSTRIA| 3 - 4 MAY 2020 23 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
● These equations are nonlinear, partial differential equations with Q and y as dependable variables and x and t as independent variables.
● The exact solutions of these equations are not possible because these equations are not in their standard form.
● Therefore, approximate solutions are obtained by using numerical methods such as finite difference, finite element and other numerical techniques.
AUSTRIA| 3 - 4 MAY 2020 24 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
Study Area, Data Sources & Data Collection
AUSTRIA| 3 - 4 MAY 2020 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
● The Dholera Special Investment Region (DSIR) is in the delta of four rivers starting from River Sukhbhadar in the North to Lilka, Utavli, and Padalio River at extreme south and local Khadi (creek) namely Bhadhar creek, Vankol creek, Bavaliyari creek and Sonrai creek.
● These rivers are east flowing rivers traversing through the DSIR area and discharges into the Gulf of Cambay.
● Sukhbhadar river is one of the major rivers traversing through the DSIR region and is taken as study area for the present study.
AUSTRIA| 3 - 4 MAY 2020 26 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
Fig. 6. Map showing the rivers and its catchment area flowing through the DISR region (http://www.gsdma.org/Content/flood-seismic-vulnerability-4206)
AUSTRIA| 3 - 4 MAY 2020 27 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
● Sukhbhadar River originates from the Vadi Hills located at the village Chotila and is one of the west flowing rivers traversing through the DSIR area and eventually meets in the Gulf of Cambay.
● The length of Sukhbhadar River is approximately 194 km and has catchment area of 2118 sq. km.
● Sukhbhadar River is enriched by number of tributaries on its way and Goma is the major tributary which meets at Ranpur.
AUSTRIA| 3 - 4 MAY 2020 28 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
● There are two major dams on Sukhbhadar River namely Sukhbhadar Dam (spillway capacity: 10699 m3/s) at village Nana Bhadla and Goma Dam at village Nana Paliyad.
● The weir known as Kotda Cut Weir on Sukhbhadar river about 6 km upstream of Dhandhuka town. The Kotda cut weir divides the flood water of Sukhbhadar River into two channels known as Northern channel flowing towards Adwal village and Southern channel flowing towards Dhandhuka town and traverses through the DSIR region and meets the gulf of Cambay.
AUSTRIA| 3 - 4 MAY 2020 29 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
● Near village Adwal on the Northern channel and village Rojka on the Southern channel, the flood water of Sukhbhadar River spills over the banks, inundates vast area and flows as sheet flow.
Sukhbhadar River passes through the Town Planning Scheme – TP1 of DSIR and one of its tributaries (Adhiya River) originates from village Cher and flows through the Town Planning Scheme – TP2 of DSIR and meets the Sukhbhadar River at village Khun.
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Fig. 7. Line diagram of Sukhbhadar River basin downstream of Sukhbhadar Dam
AUSTRIA| 3 - 4 MAY 2020 31 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
Sukhbhadar Dam is the major Dam on the Sukhbhadar River which is approximately 100 km upstream of these Town Planning Schemes. The rainfall in the catchment area of Sukhbhadar River and releases from Sukhbhadar Dam results into flooding in these areas. The river channels are undefined and the area is low lying resulting into overflanking of water from the banks and create flooding situation in the surroundings.
AUSTRIA| 3 - 4 MAY 2020 32 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
● Fig. 8. Sheet flow occurs as flood water over flanks from the banks of Sukhbhadar River 2019 AUSTRIA| 3 - 4 MAY 2020 33 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020 Table 1: Data Sources and Data Collection:
Sr. No. Data Source
1 Digital Elevation Model of study area with 30m AW3D30 resolution
2 Hourly discharge data for Sukhbhadar River Sukhbhadar Dam Authority
3 Tide data of Gulf of Cambay i.e. High tide, normal Gujarat Maritime Board tide and low tide at study area (GMB) or Kalpasar Dept
4 Predicted tidal data of Bhavnagar Port Survey of India (SOI)
5 Master plan of DSIR area DICDL / GIDB
6 Salient features of irrigation schemes of State Water Data Centre Sukhbhadar River and its tributaries (SWDC), Gandhinagar
AUSTRIA| 3 - 4 MAY 2020 34 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
Development of 1D Hydrodynamic Model
AUSTRIA| 3 - 4 MAY 2020 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020 1D HYDRODYNAMIC MODELLING IN MIKE HYDRO RIVER:
• Creating MIKE HYDRO River Model • Simulation Specifications • Map Configuration • River Network • Cross section • Boundary Conditions and Initial Conditions • Hydrodynamic Parameter • Results
AUSTRIA| 3 - 4 MAY 2020 36 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
● Steps:
● The first step is to open the MIKE ZERO window. MIKE ZERO is a toolbox to create any of the models and projects associated with the MIKE software.
● Click on the New File icon, the window to create a new file will appear. Then click on the MIKE HYDRO in product types. It will show the available format in documents i.e. MIKE HYDRO Model (.mhydro) and Cross Sections (.xns11).
AUSTRIA| 3 - 4 MAY 2020 37 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
● Select MIKE HYDRO Model. It will open the setup window of 1D hydrodynamic model of MIKE HYDRO River.
● Click on the Modules, then select model type as River. Select Hydrodynamic option in River modules.
● Click on description. As this step is optional, user may give title and description of the model.
AUSTRIA| 3 - 4 MAY 2020 38 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
● Click on Simulation period. The user has to provide the start and end time for the simulation period. For the present study 2019-10- 01 01:00:00 is given as simulation start time and 2019-10-06 21:00:00 is given as simulation end time.
● Click on the Time step control. The user has to specify the time step for the computation. Select appropriate Time step type and length for the simulation.
AUSTRIA| 3 - 4 MAY 2020 39 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
● Click on Computational control parameters. The user has to specify the grid spacing for the computation and the solution technique for wave approximation and different computational parameters. We have taken grid spacing as 100 m in the present study.
● Click on Coordinate system. The user has to define the coordinate system and projection based on the available data. In the present study, ‘WGS_1984_UTM_Zone_42N’ has been selected as Map view coordinate system and Coordinate system for other features stored in the setup file.
AUSTRIA| 3 - 4 MAY 2020 40 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
● Click on Background map. The user has the option to set the background maps such as Satellite images, Google Map, Countries/Coastline shape files, etc.
11. Click on Background layers. The user has the option to set Image, Shapefile and Raster as background layer. In the present study, shape file of Sukhbhadar River reach has been given as background layer.
AUSTRIA| 3 - 4 MAY 2020 41 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
11. Click on Digital Elevation Model. The user has to input DEM for river tracing, catchment delineation and extraction of cross sections. A number of options are provided for River tracing, Catchment delineation and cross section extraction. In the present study, AW3D30 DEM is used to generate cross sections.
11. Click on Working area. The user has the option to define the working area.
AUSTRIA| 3 - 4 MAY 2020 42 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
11. Click on the File menu, select Import, and then select Import from shapefile. It provides the options to import Branches, Alignment lines, Structures, Storage, Boundaries points and distributed sources and catchments.
12. In the present study, the model is developed for Sukhbhadar River reach from the downstream of Sukhbhadar Dam covering DSIR area to the Gulf of Cambay. The shape file of River network and alignment lines are imported as Branches and Alignment lines.
AUSTRIA| 3 - 4 MAY 2020 43 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
14. Click on Tools menu and then select Auto Generate Cross section. A window will appear with options. Select DEM and then select locations from shape file. After importing location from shapefile, click Generate.
16. Click on Boundary conditions in the setup window. Select Standard boundaries and then click on ‘Create open end boundaries’. It will automatically generate the boundary which is having an open end in the river network. Import the time series file for the respective boundaries.
AUSTRIA| 3 - 4 MAY 2020 44 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
16. Click on Initial conditions. Select HD initial conditions. In the global value, set type as user defined and set level type as Water depth of 0.1 m and Discharge type as Natural flow. For the present study, bed resistance for the river reach is given as global value i.e. for the entire river reach; same value of roughness is considered. The initial value of Manning’s n has been taken as 0.04 and for the calibration of model; it is assured that the value of coefficient of roughness is within a specified range i.e. 0.04 to 0.07 according to the type of the channel.
AUSTRIA| 3 - 4 MAY 2020 45 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
16. Click on Hydrodynamic parameters. Select bed resistance. Set Resistance formula as Manning (n) and Global value as 0.06.
Click on Result specifications. Select standard results. Set storing frequency as 1 hour and provide a name for the input file with the location.
AUSTRIA| 3 - 4 MAY 2020 46 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
Fig. 9. Steps to create MIKE HYDRO Model AUSTRIA| 3 - 4 MAY 2020 47 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
Fig. 10.Step to setup Simulation Specification in MIKE HYDRO model AUSTRIA| 3 - 4 MAY 2020 48 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
Fig. 11.River network & Cross Section Editor used in MIKE HYDRO River Model AUSTRIA| 3 - 4 MAY 2020 49 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
Fig. 12.Hourly release from Sukhbhadar Dam & tidal data of Bhavnagar Port AUSTRIA| 3 - 4 MAY 2020 50 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
Results and Discussion
AUSTRIA| 3 - 4 MAY 2020 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
16. The 1D hydrodynamic model of Sukhbhadar River has been developed in MIKE HYDRO River for the flood event of year 2019 and calibrated for simulation period of 2019-10-01 01:00:00 to 2019-10-06 21:00:00 , total period of 140 hour.
17. The maximum release from Sukhbhadar Dam during the simulation period was 250.38 m3/s.
AUSTRIA| 3 - 4 MAY 2020 52 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
16. The results of MIKE HYDRO River model has been analyzed using MIKE VIEW module of MIKE software. The MIKE HYDRO River result file is saved as .res1D format and can be opened with MIKE VIEW.
● The 1D Hydrodynamic model for Sukhbhadar River reach has been simulated for different values of Manning’s roughness coefficient n.
AUSTRIA| 3 - 4 MAY 2020 53 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
Fig. 13. The window of MIKE VIEW & Water level profile for the Sukhbhadar River AUSTRIA| 3 - 4 MAY 2020 54 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
● For the selection of Manning’s roughness coefficient “Guide for Selecting Manning’s Roughness Coefficients for Natural Channels and Floodplains by United States Geological Survey” has been referred.
● Table 1 of this guide shows the base “n” values corresponding to median size of various bed materials.
● A typical photograph showing the bed material in the Sukhbhadar River reach is shown in the Figure in the next slide.
AUSTRIA| 3 - 4 MAY 2020 55 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
Fig. 14. A typical photograph showing the River Bed of Sukhbhadar River reach AUSTRIA| 3 - 4 MAY 2020 56 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
● During site visit it was observed that for most of the bed material size was greater than 256 mm. Hence the range of Manning’s ‘’n’’ is between 0.04 to 0.07.
● The simulated results obtained from the 1D Hydrodynamic model has been analyzed using different options and comparison of water levels have been done using the depth data collected at various locations during site visit for calibration and is summarized in table 2.
AUSTRIA| 3 - 4 MAY 2020 57 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
● Photographs of the villagers crossing the river have been taken with timestamp and geotagging to get the depth of flow at a particular location at a particular time for the simulation period as shown in figure 15.
● Figure 15 shows the photographs of villagers crossing the river near village Nagnesh i.e. at chainage 86627.93 m at time 3-10-2019 11:26 AM.
AUSTRIA| 3 - 4 MAY 2020 58 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
Fig. 15. Photograph showing the depth of water at chainage 86627.93 m at time 3-10-2019 11:26 AM AUSTRIA| 3 - 4 MAY 2020 59 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
● From the figure 15 it can be seen that the depth was around 0.4 to 0.6 m. The observed depth and simulated depth corresponding to Manning’s n of 0.06 shows close agreement as shown in the figure 16.
● The observed depth and simulated depth corresponding to Manning’s value of 0.06 shows close agreement as shown in table 2 and hence is adopted as global Manning’s value for the calibration of the model.
AUSTRIA| 3 - 4 MAY 2020 60 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
● Fig. 16. Observed and simulated depth at chainage 86627.93 m at time 3- 10-2019 11:26 AM AUSTRIA| 3 - 4 MAY 2020 61 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020 Table 2: Observed and simulated depths for different values of Manning’s n:
Date & Time of Observed Simulated Location Coordinates Chainage Manning’s n Observation Depth (m) Depth (m)
0.04 0.46 22.3521 N, 3 Oct 2019 Ranpur 92327.9 0.05 0.6 0.54 71.7178 E 11:26 AM 0.06 0.61
0.04 0.34 22.3675 N, 3 Oct 2019 Nagnesh 86627.9 0.05 0.5 0.45 71.7637 E 12:30 PM 0.06 0.52
AUSTRIA| 3 - 4 MAY 2020 62 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
● The maximum and minimum Froude number for the study area was 0.045 and 2.005 respectively.
● Further from the model critical cross sections have been identified.
● The maximum simulated water levels at all cross sections with R.L. of left bank and right bank along with chainage has been shown in Table 3.
● The 1611.33 m chainage is the downstream boundary while the chainage 111300 m is the upstream boundary at the Sukhbhadar Dam.
AUSTRIA| 3 - 4 MAY 2020 63 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020 Table 3: Height of water level above river bank at all cross sections:
Cross section Left Bank Right Bank Water Level Height of water level above chainage (m) R.L. (m) R.L. (m) (m) Left Bank (m) Right Bank (m)
1611.33 6 5 5.131 0 0.131
6311.33 7 5 7.254 0.254 2.254
8111.33 6 6 7.544 1.544 1.544
12211.33 7 7 8.347 1.347 1.347
16211.33 7 7 8.840 1.840 1.840
AUSTRIA| 3 - 4 MAY 2020 64 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
Cross section Left Bank Right Bank Water Level Height of water level above chainage (m) R.L. (m) R.L. (m) (m) Left Bank (m) Right Bank (m)
20011.33 7 7 9.062 2.062 2.062
20311.33 7 7 9.071 2.071 2.071
22111.33 8 7 9.156 1.156 2.156
23811.33 9 8 9.222 0.222 1.222
26111.33 8 7 9.318 1.318 2.318
29711.33 8 8 9.438 1.438 1.438
33211.33 9 9 9.728 0.728 0.728
AUSTRIA| 3 - 4 MAY 2020 65 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
Cross section Left Bank Right Bank Water Level Height of water level above chainage (m) R.L. (m) R.L. (m) (m) Left Bank (m) Right Bank (m)
41211.33 9 10 10.433 1.433 0.433
46211.33 9.8 10 10.920 1.120 0.920
51211.33 13 13 13.814 0.814 0.814
61127.9 24 24 21.538 0 0
66127.9 29 31 26.940 0 0
71127.9 33.7 35 32.130 0 0
75327.9 39 41 39.149 0.149 0
AUSTRIA| 3 - 4 MAY 2020 66 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
Cross section Left Bank Right Bank Water Level Height of water level above chainage (m) R.L. (m) R.L. (m) (m) Left Bank (m) Right Bank (m)
80827.9 47 48 44.298 0 0
87027.9 53 53 53.132 0.132 0.132
89427.9 57 57 57.095 0.095 0.095
92127.9 61 61 61.605 0.605 0.605
95900.0 68 72 68.140 0.14 0
102800 80 85 80.779 0.779 0
111300 105 103 96.399 0 0
AUSTRIA| 3 - 4 MAY 2020 67 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
Fig. 17.Critical flood reaches of Sukhbhadar study River reach AUSTRIA| 3 - 4 MAY 2020 68 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
● From the Sukhbhadar Dam to Dhandhuka i.e. from chainage 111300 m to 55481.3 m few stretches of the villages are affected by flood waters these includes Loya, Saganpur, Ranpur, Kinara, Nagnesh and Sontha.
● From Dhandhuka to Gulf of Cambay all the villages are affected by flood waters as the discharge carrying capacity of the river in this stretch was very low.
AUSTRIA| 3 - 4 MAY 2020 69 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
● The developed 1D hydrodynamic model was run for various discharges and maximum height of retaining wall required at particular location of the study reach to prevent flooding is presented in figure 18.
● As the discharge is increased a considerable stretch of the river reach is affected by flooding specially downstream of Dhandhuka as the area is almost flat and the capacity of river is too low.
● The results from the present study can be used to suggest flood mitigation measures for the affected villages in the Sukhbhadar River reach and Special Investment Region. AUSTRIA| 3 - 4 MAY 2020 70 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
Fig. 18. Height of retaining wall required for various discharges
AUSTRIA| 3 - 4 MAY 2020 71 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
● In the present analysis embankment or retaining wall on either bank of the river has been considered as one of the flood mitigation measure. The height of retaining wall to prevent these DSIR areas vary from 1 m to 25 meters up to 2500 cumec releases from the dam.
● If retaining wall is proposed to be constructed as flood mitigation measure, it seems to be impractical and uneconomical as the required height is too high as shown in figure 18.
AUSTRIA| 3 - 4 MAY 2020 72 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
Conclusions
AUSTRIA| 3 - 4 MAY 2020 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
● The 1D hydrodynamic model have been developed for the Sukhbhadar River reach downstream from the Sukhbhadar Dam traversing through the Dholera Special Investment Region (DSIR) to the Gulf of Cambay.
● The maximum release during the simulation period was 250.38 m3/s while the design spillway capacity of Sukhbhadar Dam was 10699 m3/s.
● The developed model has been calibrated and validated for 2019 flood event and Manning’s coefficient is taken as 0.06.
AUSTRIA| 3 - 4 MAY 2020 74 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
The critical river sections and flood prone areas have been identified from 1D hydrodynamic model and it shows that from Sukhbhadar Dam to Dhandhuka i.e. from chainage 111300 m to 55481.3 m few stretches of the villages are affected by flood waters these includes Loya, Saganpur, Ranpur, Kinara, Nagnesh and Sontha. From Dhandhuka to Gulf of Cambay, almost all the villages are affected by flood as the discharge carrying capacity of the river in this stretch is very low.
AUSTRIA| 3 - 4 MAY 2020 75 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020 In the downstream of Dhandhuka, the carrying capacity of river is very low and the water which spills from the banks,flows in the form of sheet flow towards the Gulf of Cambay. In this stretch the water spreads over kilometers of length inundating vast areas. The town planning schemes TP1 and TP2 of Dholera Special Investment Region are affected by sheet flows. The situation becomes worse when there is a high tide in the Gulf of Cambay and flood in the river. In this scenario, the backwaters inundate town planning schemes 1 and 2 for several days.
AUSTRIA| 3 - 4 MAY 2020 76 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
● The results from the present study can be used to suggest flood mitigation measures for the affected villages in the Sukhbhadar River reach and Special Investment Region.
● In the present analysis embankment or retaining wall on either bank of the river has been considered as one of the flood mitigation measure.
AUSTRIA| 3 - 4 MAY 2020 77 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
The height of retaining wall to prevent these DSIR areas vary from 1 m to 25 meters up to 2500 cumec releases from the dam.
This solution may not be economical hence it is proposed to take advantage of existing number parallel natural streams and ponds to conserve flood water.
This solution seems to be more practical and economical.
AUSTRIA| 3 - 4 MAY 2020 78 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020 Limitation of study In absence of measured data of depth in the study river reach, it is difficult to validate developed model. In the present analysis model is validated using limited data collected during site visit for discharge of specific day. The gauging site Ranpur has been closed since last few years. It is recommended to make this site operative. The detailed analysis considering high releases from Sukhbhadar Dam and measured depth in the river and flood plain area help to strengthen this study. The role of storage reservoirs, existing canal network,newly constructed roads, storm drains and other proposed flood mitigation measures are not considered in the present analysis. AUSTRIA| 3 - 4 MAY 2020 79 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
Funding
This work was supported by TEQIP-III grant under Micro Research Project Grant.
AUSTRIA| 3 - 4 MAY 2020 Dr S M Yadav, Professor,CED,SVNIT,SURAT EGU 2020
Thank you
● Corresponding Author : Dr S M Yadav,Professor,CED,SVNIT,Surat,(India) e mail:[email protected]
AUSTRIA| 3 - 4 MAY 2020 Dr S M Yadav, Professor,CED,SVNIT,SURAT