Drainage & stormwater network design and modelling
- Urban drainage networks, storm sewers and culvert systems
- Stormwater pump stations, detention basins and outfalls
- Flooding, surcharge and overflow assessments under design storms
We support municipalities, consultants and EPC contractors with hydraulic modelling and design of drainage and stormwater systems. Our work helps you to manage flood risk, size critical assets correctly and demonstrate performance under regulatory and client requirements.
Why drainage & stormwater modelling matter
More intense rainfall, urbanisation and tighter regulations are putting stormwater systems under pressure. Inadequate drainage can lead to property flooding, road closures, environmental spills and reputational damage for asset owners.
Robust drainage modelling and design allow you to:
- Check system performance for a range of design storms and climate scenarios
- Identify surcharging manholes, flooding locations and capacity bottlenecks
- Size pipes, culverts, detention basins and pump stations correctly
- Demonstrate compliance with local guidelines and client requirements
- Prioritise improvements and support business cases for capital works
What we offer in a drainage & stormwater study
1. Data review & base model
- Review of existing drainage layouts, GIS, surveys and as-built information
- Definition of catchment boundaries, subcatchments and key outfalls
- Set-up or refinement of SWMM / InfoWorks ICM base models
- Representation of storage, pumps, controls and overflow paths
2. Hydrology, hydraulics & scenarios
- Application of design storms and runoff methods appropriate to the site
- Simulation of system response under multiple rainfall events and durations
- Assessment of surcharging, flooding and spill locations
- Testing of proposed upgrades, diversions or online/offline storage options
3. Design refinement & mitigation
- Sizing and optimisation of pipes, culverts, basins and pump stations
- Evaluation of green/blue infrastructure and attenuation options
- Recommendations to reduce flood risk and improve resilience
- Clear input to concept and detailed design stages
Typical deliverables
A typical drainage and stormwater study will provide the following outputs, tailored to the scope and stage of your project:
- Summary report highlighting key risks, flooding locations and recommended works
- Maps of peak water levels, depths, velocities and surcharge extent
- Profiles and long sections for critical pipes, culverts and structures
- Comparison of “existing” versus “with improvements” options
- Sizing and design criteria for major assets such as basins and pump stations
- Updated model files and run files, on request, for your internal use
Tools and methods
We apply recognised software and hydrological methods, combined with practical engineering judgement, to ensure reliable and defensible results.
- Hydraulic software: SWMM, InfoWorks ICM and similar drainage tools
- Hydrology: design storms and runoff methods in line with local guidance
- Data inputs: rainfall data, land-use information, surveys and flow data where available
- Verification: sanity checks, sensitivity runs and comparison with known issues
- Outputs: maps and reports designed to support decision making and approvals
How we typically work with you
Step 1 – Brief & data
We confirm the objectives of the study, review existing information and agree key locations, performance criteria and deliverables with your team.
Step 2 – Modelling & options
We build or refine the drainage model, run the agreed rainfall scenarios and test practical options to reduce flood risk and improve performance.
Step 3 – Recommendations & handover
We present findings, document recommendations clearly and provide plots and model files that support approvals and future scheme development.