Introduction

A demonstration model and small suite of simulations have been developed to support TUFLOW CATCH users. These simulations:

Can be used as templates for construction of other TUFLOW CATCH simulations
Encompass the supported TUFLOW CATCH configurations, and
Are able to be run without a licence for TUFLOW CATCH, TUFLOW HPC or TUFLOW FV

Descriptions of the model and demonstration simulations follow.

Demonstration Project Area Domain

The demonstration model is located in New Zealand. It uses publicly available base data sets where available (with some of these being modified on occasion), and synthetic data otherwise.

The model domain is simulated under TUFLOW CATCH, which subsequently controls TUFLOW HPC and FV, for a period of 1 week from 01/01/2021 to 07/01/2021.

The catchment (represented by TUFLOW HPC) has:

An area of approximately 55km^2.
A relief of approximately 20m.
Three (synthetic) land uses: urban, forest and agriculture.

The general arrangement of the catchment is presented below.

The receiving waterway, which is a hypothetical lake (represented by TUFLOW FV) has:

An area of approximately 1km^2
A maximum depth of approximately 12m
Two major riverine tributaries
Two local wastewater treatment plant discharges
One offtake
An overflow outlet weir

The general arrangement of the receiving waterway is presented below.

Numerical Models

The TUFLOW HPC catchment runoff / pollutant export and TUFLOW FV receiving water models are described following.

TUFLOW HPC

The TUFLOW HPC model has the following general configuration:

A 2D cell size of 50m, SGS turned on with a sample target distance of 1m
A synthetic rainfall record applied, with a maximum daily rainfall of approximately 60mm
Three materials, with one for each land use above
One soil layer with constant thickness of 0.6m
All simulations use GPU Module acceleration.

The pollutant export model in TUFLOW HPC has various forms depending on the TUFLOW CATCH configuration being simulated. Across these various forms, both shear1 and washoff1 methods are deployed, and other pollutant export parameters are set using the guidance provided in the TUFLOW CATCH manual. In all cases where applicable:

Salinity, dissolved oxygen, silicate, adsorbed phosphorus and phytoplankton are set to constant concentrations
Sediment and particulate organics are prohibited from infiltrating to groundwater
Water temperature is provided as a timeseries
Sediment uses the shear1 method, and all other pollutants use the washoff1 method

TUFLOW FV

The TUFLOW FV model has the following general configuration:

Simulation of hydrodynamics, including density (salinity and temperature) driven processes
Full atmospheric heat exchange simulation
Sediment transport simulation, with one sediment fraction
Water quality simulation, using the Organics simulation class
3D simulation with 8 z layers and 6 sigma layers
Three bed materials to define sediment transport and water quality processes
All simulations use GPU Module acceleration.

Suite of Demonstration Cases

The demonstration model suite includes the following simulations. Simulation name Description Use case TUFLOW CATCH Configuration Demonstration_001.tcc Catchment hydraulic calibration: HPC 2d outlet Calibration of catchment hydraulic model without receiving model TUFLOW HPC calibration only Demonstration_002.tcc Catchment hydraulic calibration: Pollutant export configuration with constant salinity and temperature timeseries Calibration of catchment hydraulic model with downstream polygon Pollutant export Demonstration_003.tcc Catchment pollutant calibration: Pollutant export configuration with user pollutant/s Only catchment hydraulic and pollutant export models are to be used, with non-TUFLOW FV pollutants and downstream polygon Pollutant export Demonstration_004.tcc Catchment pollutant calibration: Pollutant export configuration with TUFLOW FV pollutants Calibration of catchment pollutant export model following 002 calibration, to TUFLOW FV pollutants with downstream polygon Pollutant export Demonstration_005.tcc Linked catchment and receiving model: Integrated configuration with all TUFLOW FV pollutants Generation of first pass spatially resolved TUFLOW FV HD and pollutant boundaries for subsequent TUFLOW FV calibration initiation Integrated Demonstration_006.tcc Receiving model calibration: TUFLOW FV simulation with preserved inflows Catchment hydraulic and pollutant modelling complete (or largely so) and TUFLOW FV is to be calibrated without reunning catchment model Integrated Demonstration_007.tcc Linked catchment and receiving model: Hydrology configuration with salinity and temperature No pollutant simulation required in TUFLOW - extend 002 above to include TUFLOW FV model Hydrology

Data Documentation and Download

The demonstration models are fully documented in the TUFLOW CATCH manual. The associated model files are available via the TUFLOW Downloads.

TUFLOW CATCH Demo Models

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