1D Channels, Structures and Pipe Networks

World Leading Solver and 1D/2D Linking

TUFLOW's 1D solver (ESTRY) was originally developed in the early 1970's using punch cards(!). It has undergone continued enhancements and performance improvements to the present day. It has very much been the unsung hero of TUFLOW's success by consistently demonstrating accuracy, excellent calibrations, numerical stability and speed.  

ESTRY is feature filled. It caters for 1D open channels, culverts, underground pipe networks, manholes, pumps, weirs, bridges and a wide array of operational mode (dynamic rule based) structures. TUFLOW's 1D/2D linking is world leading in terms of its stability and heritage (originally dating back to 1991, TUFLOW was the first successful 1D/2D hydraulic modelling software in the world). Today, 1D/2D integrated urban catchment modelling is one of TUFLOW's most popular applications due to:

  • TUFLOW HPC's speed using GPU hardware and efficient memory treatment: TUFLOW can happily accommodate over 10,000,000 2D cells without issue on inexpensive GPU cards.
  • ESTRY's detailed underground pipe network calculation approach: ESTRY can fully accommodate pressurised or non pressurised conditions. Hydraulic losses throughout the network are calculated dynamically every computational timestep based on local hydraulic conditions and pipe geometry, angle of approach/departure and manhole chamber or pipe junction characteristics.

Rapid simulation demands associated with flood forecasting and Monte Carlo simulation is resulting in a renewed interest in 1D modelling for river and catchment applications. The most recent high profile application was as the "Fast Model" for the exhaustive Brisbane River Catchment Comprehensive Hydraulic Assessment.  Successfully calibrated to tidal flows and five minor to major floods, the model was the foundation for more than 11,000 Monte Carlo simulations to derive design floods varying in probability from 1 in 5 to 1 in 10,000 AEP.

ESTRY is packaged with TUFLOW's 2D Grid/Quadtree Mesh hydraulic solvers (TUFLOW Classic / HPC).

Open Channels

TUFLOW's 1D open channel network modelling is feature packed. For example, modellers can:

  • Enter cross-sections as XZ profiles or height-width tables.
  • Vary resistance across sections by either Manning's n or relative resistance and sample values from GIS land use layers.
  • Choose between effective or total area calculation methods.
  • Select different approaches to calculate parallel channel conveyance.
  • Define storage areas for floodplain detention zones.
  • And much more!

TUFLOW imposes no limit on the number of modelled 1D channels, which translates to constraint-free networking. TUFLOW's 1D solution is exceptionally stable - unlike other commonly used dynamic mode 1D software, TUFLOW demonstrates no wet/dry issues. Start simulations with all channels dry, and then have no fear in launching long-term simulation of ephemeral waterways that regularly dry and rewet.


Pipe Networks

TUFLOW's pipe network functionality can accurately model 1D stormwater networks with over 10,000 pipes, seamlessly linking to overland 2D domains. The pipe solution scheme:

  • Accurately accounts for non-pressurised and pressurised pipe flows.
  • Automatically adjusts entrance/exit energy losses according to approach/departure velocities, and can adjust down to zero losses with no stability issues.
  • Adjusts junction/manhole losses dynamically every timestep based on the hydraulic conditions and pipe sizes/inverts/angles, alternatively losses can be fixed using published parameters.
  • Includes a range of pit inlet options from automatic capture rates to defined depth-discharge relationships.
  • 2D sub-grid sampling and Quadtree meshing facilitates accurate predictions of depths at pit inlets.
  • Unlimited number of pipes/pits/manholes mean there are no constraints on networking.

Wide Range of Structures

TUFLOW's 1D solver incorporates a full range of fixed and operational structures.  Built-in fixed structure functionality includes:

  • Rectangular, circular and irregular shaped culverts.
  • Full range of weir types from V-notch to broad-crested to user defined.
  • Benchmarked or customised submergence curves. 
  • Bridges that automatically switch in/out of pressure flow and vary losses with height.
  • Automatic adjustment of contraction/expansion losses according to approach/departure velocities.
  • Spillways, pumps and other specialised structures.
  • User defined height-flow curve or matrix for downstream controlled condition.


Image of weir flow

Operational Structures

Use TUFLOW's powerful scripting to set up logical rules for operated structures. This feature allows the user to control hydraulic aspects, such as flow rates, or alternatively geometric aspects, such as structure opening percentage and time varying opening rates. Operational controls are available for the following structures.

  • Pumps.
  • Gated culverts.
  • Sluice gates.
  • Gated spillways.
  • Adjustable, gated or inflatable weirs.
  • User-defined height-discharge relationships can also be used to hardwire different hydraulic conditions.