SWMM green-infrastructure performance study
A completed EPA SWMM study comparing bioretention, permeable pavement, detention, and a combined strategy across five design storms and one synthetic continuous year.

Project definition
Problem statement
Green infrastructure can reduce runoff at the source, while detention can delay and control discharge. Their effects change with rainfall severity and drainage-network capacity.
A useful comparison must measure runoff, peak outfall flow, flood volume, storage use, emergency overflow, and numerical continuity together.
Project objectives
- Build one controlled 50-hectare urban drainage catchment in EPA SWMM.
- Compare baseline, bioretention, permeable pavement, detention, and combined scenarios.
- Test 2-year, 5-year, 10-year, 25-year, and 50-year design storms.
- Run a deterministic synthetic continuous year with 8,760 hourly rainfall values.
- Measure peak flow, outfall volume, flooding, infiltration, storage use, overflow, and continuity error.
Project structure
Project components
Rainfall generator
Creates five depth-preserving three-hour design storms and one reproducible synthetic continuous year.
SWMM model
Defines four subcatchments, pipes, outfalls, bioretention, permeable pavement, detention, controlled discharge, and emergency overflow.
Simulation study
Runs all thirty cases with the pinned official EPA SWMM 5.2.4 engine.
Result parser
Extracts runoff, outfall, flooding, storage, overflow, and continuity evidence from retained reports.
Analysis
Builds comparison tables, structured summaries, and eight labelled engineering figures.
Methodology
Project workflow
- 01Select rainfall
Choose one design storm or the synthetic continuous year.
- 02Select scenario
Choose baseline, bioretention, permeable pavement, detention, or combined controls.
- 03Generate model
The workflow writes the complete SWMM input with the selected rainfall and control objects.
- 04Run SWMM
The pinned engine performs hydrologic and dynamic-wave hydraulic simulation.
- 05Compare evidence
Retained tables and figures show source reduction, peak control, flooding, storage saturation, and exceedance.
Demonstration scenario
The combined strategy lowers the 2-year peak from 6.110 to 2.212 cubic metres per second, removes modelled 5-year flooding, and reduces 10-year flooding by 63.9 percent. Storage becomes full by the 10-year event, so the student can explain why benefit falls during exceedance instead of presenting one universal reduction percentage.
Engineering
Tools and method
- Tools
- The project uses EPA SWMM 5.2.4, Python, NumPy, Pandas, Matplotlib, Jupyter for subject analysis, simulation, and results.
- Hydrology
- EPA SWMM models rainfall, depression storage, Green-Ampt infiltration, evaporation, and runoff.
- Hydraulics
- Dynamic-wave routing represents pipe capacity, backwater, surcharge, node flooding, storage, and overflow.
- Green infrastructure
- Bioretention and permeable pavement use documented SWMM LID layer and routing definitions.
- Reproducibility
- Docker builds the exact official SWMM source commit inside a digest-pinned Debian runtime.
- Verification
- Automated tests cover rainfall, model objects, report parsing, execution, study orchestration, and figures.
Testing
Evaluation
Evaluation measures
- Peak outfall flow across five design storms
- Outfall volume and runoff reduction
- Node flood volume and flood reduction
- Detention utilisation and emergency overflow
- Continuous-year infiltration, outfall volume, and water balance
- Runoff and routing continuity error for every case
Project boundaries
- The catchment, rainfall, soil, network, and control sizes are declared teaching assumptions.
- The model is not calibrated against monitored rainfall, flow, water level, or flooding.
- The study does not provide surveyed geometry, local frequency analysis, construction details, cost, maintenance evidence, or regulatory approval.
- Field use requires site data, calibration, local standards, and qualified civil engineering review.
Included
- 01Complete EPA SWMM model and Python study workflow
- 02Thirty completed simulation cases
- 03Five design storms and one synthetic continuous year
- 04CSV, JSON, and eight result figures
- 05Twenty-six automated tests with 98 percent combined coverage
- 06Complete project files, model, calculations, and analysis material in a private GitHub repository
- 0795-page project documentation in PDF and editable Word formats
- 0821-page setup and usage guide in PDF and editable Word formats
- 09Forty-five annotated references
Project record
No information is collected on this page.
- Permanent project ID
- GP-CV-0IEPBT4
- Catalogued
- 21 Aug 2026
- Completed
- 24 Aug 2026
- Verified
- 24 Aug 2026
- Demonstration
- Included in repository
Handover
After purchase
- 01Payment is confirmed
The project is marked unavailable and cannot be purchased again.
- 02Repository access is granted
The buyer's submitted GitHub account receives access to the private repository.
- 03The purchase record is delivered
The certification sheet is prepared from the reviewed buyer details and sent privately by email.