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Basin Planner
Smarter stormwater management for a changing climate
Design for reality, not just for a single rainfall event. Basin Planner is a calculation and design tool for stormwater facilities that handles the full range of return periods, not just a single design rainfall event.
The result is increased retention, better treatment and more natural flow patterns.
Why traditional stormwater design falls short
Urban environments are changing fast. Cities are expanding, sealed surfaces are increasing and climate change is driving more intense rainfall events.Yet many stormwater systems are still dimensioned for just one rainfall scenario.This creates real risks:
- Undersized retention systems
- Unintended frequent and intense flooding downstream
- Greater pressure on receiving water bodies as more untreated water is discharged
- Conflicts with downstream landowners
In early planning stages, errors in volume and surface estimations can reach up to 30%. Smaller but highly polluted rainfall events often pass through untreated, adding stress to already vulnerable water systems.
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A better approach: design for reality, not assumptions
Basin Planner has been developed by experts in hydraulics to enable more accurate and robust design of stormwater systems, ensuring functionality across the entire flow spectrum up to the design flow level, not just at a single design flow.
Instead of using simplified point flows, entire rainfall events are modelled as time series. Through a time-stepped mass balance, the development of water level, volume, inflow and outflow in the system over time is calculated continuously.
At the heart of the model is a physics-based description of outlet structures, where flow is governed by outlet geometry and the current water level. Different types of outlets are modelled using established hydraulic relationships and automatically switch between flow regimes depending on submergence and pressure conditions
The result is an optimised system in which both reservoir volume and outlet geometries are scaled down to precise dimensions to achieve the right balance between storage, flow regulation and hydraulic capacity – tailored to the site’s specific hydrological conditions.
A flexible service, from early planning to implementation
Basin Planner supports the entire stormwater process:
- Early-stage planning and investigation
- Detailed planning and design
- Construction phase
- Optimisation and modification of existing systems
Package 1 - Investigation
Modelling of complete rainfall sequences, sizing and optimisation of storage basins and outlet geometries, analysis of the hydrological regime, and reports that can, for example, support the approval of detailed development plans or ensure correct sizing for land drainage contractors.
Package 2 – Design/construction phase
Design of outlet solutions, construction-ready drawings, site-specific geometries and documentation for manufacturing.
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