Urban Stormwater & Flood Management
Slow, store, infiltrate where safe and discharge rainfall without transferring risk.
Define the service failure before selecting infrastructure.
Flooding results from rainfall interacting with terrain, blocked or undersized drainage, lost storage and exposure.
Drain enlargement alone can transfer peak flow downstream.
Record state, district, city/block, village/ward or supply zone; season and date; source or asset; affected users; observed service; measurement or sample method; photo/document where safe; and uncertainty. Never imply 100-metre accuracy unless the evidence genuinely supports it.
Test the full source-to-service chain.
Natural drainage and wetlands built over
Treat this as a hypothesis until records, field observation, seasonal evidence and credible alternatives are checked.
Maintenance condition not mapped
Treat this as a hypothesis until records, field observation, seasonal evidence and credible alternatives are checked.
Design rainfall and growth assumptions outdated
Treat this as a hypothesis until records, field observation, seasonal evidence and credible alternatives are checked.
Solid waste and sewage reduce capacity
Treat this as a hypothesis until records, field observation, seasonal evidence and credible alternatives are checked.
Components that must work together.
Flood-risk and drain-capacity mapping
Define the responsible actor, operating standard, input, handoff, maintenance requirement, failure trigger and evidence record.
Drain maintenance
Define the responsible actor, operating standard, input, handoff, maintenance requirement, failure trigger and evidence record.
Retention ponds and urban wetlands
Define the responsible actor, operating standard, input, handoff, maintenance requirement, failure trigger and evidence record.
Permeable surfaces and rain gardens
Define the responsible actor, operating standard, input, handoff, maintenance requirement, failure trigger and evidence record.
Temporary storage
Define the responsible actor, operating standard, input, handoff, maintenance requirement, failure trigger and evidence record.
Early warning and safe discharge
Define the responsible actor, operating standard, input, handoff, maintenance requirement, failure trigger and evidence record.
Match intervention to hydrogeology, settlement and service capacity.
Model catchments and verify with flood histories.
Restore conveyance plus distributed retention and safe overflow.
Protect critical facilities and evacuation routes.
Maintain drains before monsoon and publish closure evidence.
Diagnose, protect, pilot, measure and institutionalise.
Verify & protect
Confirm the location, affected users, service chain, immediate health or safety risk, responsible agency and existing evidence.
Controlled pilot
Retrofit one flood-prone catchment with verified cleaning, retention, permeable areas and warning triggers.
Durable system
Fund operations, preventive maintenance, skilled teams, monitoring, public reporting, correction pathways and independent evaluation.
Measure service and outcomes—not assets alone.
Water interventions can transfer risk across people, places and time.
- RiskDownstream transferPrevention · accountable owner · trigger · remedy
- RiskUnsafe open storagePrevention · accountable owner · trigger · remedy
- RiskEviction without safeguardsPrevention · accountable owner · trigger · remedy