Flood Modeller Tutorial Module02

Introduction

In this tutorial we will add a representation of a proposed development which involves adding TUFLOW 1D pipe network elements into the existing model network to represent the drainage network, which will then be linked with Flood Modeller Pro.

This will involve:

• Modification of the floodplain topography by the creation of a 3D TIN surface;
• Revising the land use;
• The addition of pipes and pits to represent an underground drainage network;
• Linking the pipe network to Flood Modeller; and
• The addition of an inflow into the pipe network.

GIS and Model Inputs

The steps necessary to modify each of the GIS inputs are demonstrated in MapInfo, ArcGIS and QGIS. At each stage please select your GIS package to view relevant instructions.

Define Elevations (Building a TIN)

We have provided the GIS layers necessary to modify the ground elevations to represent the proposed development. This part of the tutorial will demonstrate how a TIN is created from these GIS layers. We will also update the GIS defining the road crest level. Follow the instructions below for your preferred GIS package.

• ArcGIS
• MapInfo
• QGIS

Define Surface Roughness

We have provided the GIS layers necessary to modify the land use areas that will change as part of the proposed development. This part of the tutorial will require populating the layer attributes to assign Manning’s n roughness values to each land use. Follow the instructions below for your preferred GIS package.

• ArcGIS
• MapInfo
• QGIS

Define Pipe Network

This part of the module creates the GIS layers that make up a pipe network. The pits of the pipe network will be linked to the 2D domain. We will also create the pit inlet database which links the GIS layers to depth-discharge curves. Follow the instructions below for your preferred GIS package.

• ArcGIS
• MapInfo
• QGIS

Define Boundary Conditions

This part of the module demonstrates how an inflow can be applied directly to the pits of the pipe network. A GIS layer of the inflow boundary has been provided. We will also modify the existing Boundary Conditions Database to include these new inflows. Follow the instructions below for your preferred GIS package.

• ArcGIS
• MapInfo
• QGIS

Flood Modeller 1D/1D Link

TUFLOW models can also be configured with Flood Modeller for dynamically linked 1D pipe network 2D overland flow modelling. The main driver for this feature is for Flood Modeller - TUFLOW models to utilise the powerful pipe network and manhole modelling capabilities of TUFLOW (see Section 5.12) and be able to link these networks into a Flood Modeller river model.

Flood Modeller and TUFLOW (ESTRY) nodes will be considered linked if:

1. An ESTRY node in a 1d_nwk layer, and a Flood Modeller node in a Read GIS ISIS Nodes or Read GIS ISIS Network layer are snapped.
2. The ESTRY node has a 1d_nwk Conn_1D_2D attribute of either "X1DH" or "X1DQ".

(i) If Conn_1D_2D is blank then “X1DH” is assumed.

(ii) A connector "X" channel type can be used to connect the end of the linked ESTRY channel to the ESTRY node snapped to the Flood Modeller node if the end of the ESTRY channel and the snapped Flood Modeller /ESTRY nodes are not in the same location.

(iii) Note that the upstream and downstream inverts for the ESTRY node linked to Flood Modeller should be set to -99999 unless the node is also being used to set the inverts of channels snapped to it.

3. An "X1DH" link means a Flood Modeller 1D water level is being applied at the ESTRY node (ie. Flood Modeller sends ESTRY a water level and ESTRY sends back a +/- flow to Flood Modeller).
4. An "X1DQ" link means a Flood Modeller inflow/outflow is being applied at the ESTRY node (ie. Flood Modeller sends ESTRY a +/- flow and ESTRY sends back a water level).
5. An ESTRY X1DH (the default) would be used for most Flood Modeller ESTRY links. An X1DQ might be more appropriate where a Flood Modeller model stops and flows into an ESTRY model.
   

Generally, an ESTRY timestep will be smaller than the Flood Modeller timestep. In these cases, the total volume is accumulated over all ESTRY timesteps within a Flood Modeller timestep, and applied to the Flood Modeller model as a discharge by dividing the volume by the Flood Modeller timestep. The mass balance _MB1D.csv file includes four new columns:

• X1DH V In: The volume of water in via a X1DH link.
• X1DH V Out: The volume of water out via a X1DH link.
• X1DQ V In: The volume of water in via a X1DQ link.
• X1DQ V Out: The volume of water out via a X1DQ link.

The type or existence of a connection can be checked by viewing the Conn_1D_2D attribute in the 1d_nwk_N_check layer. The _messages.mif/.shp layer contains CHECK 1393 messages at each ESTRY node linked to a Flood Modeller node.

Modify Simulation Control Files and Set-up a TUFLOW Scenario

Now that we have made all of the necessary changes to the GIS layers, we need to update our control files to include all the changes representing the proposed development.

TGC File

There have been two changes to the model that impact the TGC file:

• We have created two layers that together form a 3D TIN representing changes to the ground elevations.
• We have created two 2d_mat layers that represent changes to the land use at the location of the proposed development.

1. Begin by opening FMT_M01_001.tgc in your text editor. Save the file as FMT_M02_001.tgc.
2. Open FMT_M02_001.tgc
   MapInfo Users
   
3. We will now add the commands to modify the topography to represent the proposed development. Add the following commands after the READ GIS Z Shape line:



Create TIN Zpts WRITE TIN == mi\2d_ztin_FMT_M02_development_001.MIF | mi\2d_ztin_ FMT_M02_development_001.MIF

The Create TIN Zpts Write TIN command creates and writes an SMS .tin file to the same location as the GIS layer (in this case the TUFLOW\model\mi folder). The TIN can be viewed, checked and modified in SMS. This can then be read into the model directly using the Read TIN zpts command for any subsequent model simulations. Our intention for the 2d_mat layers created in this module is for them to build upon the existing commands which modify roughness. We would like for the new layers to overwrite the existing layers at the location of the proposed development. This process of layering and building up the model is a powerful tool in TUFLOW that minimises data duplication and provides a means of quality control. We need to ensure that the commands reading in our new 2d_mat layers are read in after the existing commands.

Read GIS Mat== mi\2d_mat_FMT_M02_DEV_001.MIF

Read GIS Mat== mi\2d_mat_FMT_M02_DEV_Buildings_001.MIF

QGIS or ArcGIS Users

4. We will now add the commands to modify the topography to represent the proposed development. Add the following commands after the READ GIS Z Shape line:



Create TIN Zpts WRITE TIN == gis\2d_ztin_FMT_M02_development_001_R.shp | gis\2d_ztin_ FMT_M02_development_001_P.SHP

The Create TIN Zpts Write TIN command creates and writes an SMS .tin file to the same location as the GIS layer (in this case the TUFLOW\model\gis folder). The TIN can be viewed, checked and modified in SMS. This can then be read into the model directly using the Read TIN zpts command for any subsequent model simulations. Our intention for the 2d_mat layers created in this module is for them to build upon the existing commands which modify roughness. We would like for the new layers to overwrite the existing layers at the location of the proposed development. This process of layering and building up the model is a powerful tool in TUFLOW that minimises data duplication and provides a means of quality control. We need to ensure that the commands reading in our new 2d_mat layers are read in after the existing commands.

Read GIS Mat== gis\2d_mat_FMT_M02_DEV_001_R.MIF

Read GIS Mat== gis\2d_mat_FMT_M02_DEV_Buildings_001_R.MIF

5. Save the file. The .tgc file is now ready to be used.

ECF File

There have been three changes to the model that impact the ECF file:

• We have created a 1d_nwk layer representing the culverts of the proposed pipe network
• We have created a 1d_nwk layer representing the pits of the proposed pipe network
• We have created a pit inlet database that links depth-discharge curves to the pit inlet type.
  

1. Open FMT_M01_001.ecf in your text editor. Save the file as FMT_M02_001.ecf.
2. Open FMT_M02_001.ecf
   MapInfo Users
   
3. Add the following commands at the bottom of the file as follows:

   Read GIS Network == mi\1d_nwk_FMT_M02_Pipes_001.MIF

   Read GIS Network == mi\1d_nwk_FMT_M02_Pits_001.MIF

   Pit Inlet Database == ..\pit_dbase\pit_inlet_dbase.csv

   QGIS or ArcGIS Users
   
4. Add the following commands at the bottom of the file as follows:

   Read GIS Network == gis\1d_nwk_FMT_M02_Pipes_001_L.shp

   Read GIS Network == gis\1d_nwk_FMT_M02_Pits_001_P.shp

   Pit Inlet Database == ..\pit_dbase\pit_inlet_dbase.csv

5. Save the file. The 1D control file is now ready to be used.

TBC File

There has been one change to the model that impacts the TBC file:

• We have created a 2d_sa layer to define inflows into the pipe network.

1. Open FMT_M01_001.tbc in your text editor and save as FMT_M02_001.tbc
MapInfo Users

2. Insert the following commands after the existing Read GIS SA == mi\2d_sa_M01_002.MIF command:

   Read GIS SA PITS == mi\2d_sa_FMT_M02_001.MIF

   QGIS or ArcGIS Users
   
3. Insert the following commands after the existing Read GIS SA == gis\2d_sa_M01_002_R.shp command:

   Read GIS SA PITS == gis\2d_sa_FMT_M02_001_R.shp

4. Save the file. The tbc file is now ready to be used.

TCF File

We will need to create a new tcf file that references the new tgc, ecf and tbc files.

1. Open FMT_M01_001.tcf and save as FMT_M02_DEV_001.tcf. Update the following commands:

   Geometry Control File == ..\model\FMT_M02_001.tgc

   ESTRY Control File == ..\model\FMT_M02_001.ecf

   BC Control File == ..\model\FMT_M02_001.tbc

2. We have also created a new bc_dbase in this module which will need to be referenced. Update the command as follows:

   BC Database == ..\bc_dbase\bc_dbase_FMT_M02.csv

3. Lastly, update the following command to specify a new output folder for the results of this module:

   Output Folder == ..\results\FMT_M02\2d

4. Save the file. The tcf file is now ready to be used.