1D Open Channels

Page Under Construction

Introduction

Open waterways (channels) are most commonly modelled as "S" type channels, the S signifies a sloping channel that can handle steep, super-critical flows. Open channels can either be modeled as an inertial or non-inertial channel, the latter removes the Courant stability condition and is useful for stabilizing very short S channels with high velocities.

Examples of open channels that could be modelled in 1D

London, UK (pht: Rohan King)

Sunday Creek, Australia

Basic Commands

Within the *.ecf the following commands and files are at a minimum required to a model an open channel:

Read GIS Network ==..\model\mi\1d_nwke_xxxxx.MIF ! network layer containing "S" channel alignments
Read GIS Table Links ==..\model\mi\1d_xs_xxxxx.MIF ! corresponding cross-section polylines

The tutorial model here runs through the necessary layers and setup for a 1D open channel within a model.

Error trapping

• under construction

1D/2D boundary - spill level

Ideally the location of the HX polyline, that represents the 1D/2D boundary, should be situated along the bank of the open channel. This is covered more in Section 8.2.1.1 within the TUFLOW manual. In situations where the Digital terrain model does not properly define the bank elevation it can be necessary to include ZP points that are snapped to the HX lines that work in the same way as variable z line modifications. Details on how to set up this GIS layer can be found here.

Read GIS Z HX Line ==..\model\mi\2d_bc_xxxxx.MIF ! Uses HX lines and ZP points from a 2d_bc layer

Typical check files used

The table below highlights some of the commonly used check files when reviewing 1D open channels. The full list of TUFLOW check files can be found here.

Filename prefix / suffix
_hydroprop_check.mif _hydroprop_check_L.shp
_inverts_check.mif _inverts_check_P.shp
_iwl_check.mif _iwl_check_P.shp
_nwk_C_check.mif _nwk_C_check_L.shp
_nwk_N_check.mif _nwk_N_check_P.shp
_WLLo_check.mif _WLLo_check_L.shp _xWLLo_check.mif _xWLLo_check_L.shp
_WLLp_check.mif _WLLp_check_P.shp _xWLLp_check.mif _xWLLp_check_P.shp
_xsl_check.mif _xsl_check_L.shp
_x1d_chans_check.mif _x1d_chans_check_L.shp
_x1d_nodes_check.mif _x1d_nodes_check_P.shp

Any further questions please email TUFLOW support: support@tuflow.com

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