Virtual pipes map stormwater flood paths accurately, quickly and affordably

“Virtual pipes” mapping methodology simulated dynamic stormwater systems.

Heavy flooding and weather events in a large council area showed that overland flow mapping was out of date.

Our Client



Asset value

$3+ billion


2 million

To update the overland flow maps, our client needed to map over 1,000 km2 area, including over 200,000 pipelines, 10,000 culverts and a large number of bridges. The map also needed to include a high level of detail so traditional methods would have been costly and time-consuming. To account for the likelihood of increased flooding due to climate change, our client wanted to find a better way to keep maps up-to-date.

Global benchmark for flood flow mapping

We developed a groundbreaking methodology to map the pipes digitally, saving significant time and money.

We modeled virtual pipes to simulate stormwater systems using TUFLOW GPU software. Each inlet and outlet was represented as a point in TUFLOW GIS layers. Inlets were represented by depth versus discharge capture curves. Outlets were represented by point sources with a specified maximum discharge capacity.

Within a pipe group, flows captured at inlets were dynamically transferred to the outlets. To ensure inlets and outlets were accurately identified and reduce manual processing, we developed a flexible GIS pre-processing toolset that was able to receive and process existing GIS stormwater data to identify groups of pipes, fill gaps in the existing data and generate the TUFLOW GPU input files.

Reducing costs and risks with digital mapping

As a result of this novel approach, the client was able to:

— Accurately and quickly identify potential flood flow and plan for an increase in flooding that may result from climate change.

— Reduce the cost of mapping the overland flow areas considerably, leaving more budget for mitigation projects.

— Reduce the cost of flood damage to the community, property and infrastructure.

— Use the data to improve urban planning within the region.

— Set a new global benchmark for assessing overland flow flood risks.

Find out more or get a customized solution from GHD today.