The 8 chapters that engineers reference most.
| Chapter | Title | Category | Key search |
|---|---|---|---|
| Ch. 1 | Introduction and Design Considerations for Urban Drainage | Planning | design return period |
| Ch. 2 | Rainfall Analysis and IDF Curves | Rainfall | IDF curve |
| Ch. 3 | Runoff Estimation – Rational Method and C Coefficients | Runoff | Rational method |
| Ch. 4 | Advanced Runoff Methods – SCS-CN, Hydrograph, and Modeling | Runoff | SCS curve number |
| Ch. 5 | Storm Sewer Hydraulics – Manning, Velocity, Depth | Hydraulics | Manning equation |
| Ch. 6 | Catchment Characterisation and Drainage Districts | Catchment | drainage district |
| Ch. 7 | Storm Sewer Network Design – Layout, Sizing, Gradient | Network | storm sewer layout |
| Ch. 8 | Inlets, Catch Basins and Gully Pits | Inlets | kerb opening inlet |
| Ch. 9 | Outfalls, Disposal and Pumping Stations | Outfalls | outfall design |
| Ch. 10 | Detention, Retention and Sustainable Urban Drainage (SUDS) | SUDS | detention basin |
| Ch. 11 | Urban Flooding Management and Climate Resilience | Flooding | urban flooding |
| Ch. 12 | Operation, Maintenance and Smart Drainage | Ops & IoT | drainage O&M |
The CPHEEO Manual on Storm Water Drainage Systems (2019, the first dedicated edition) gives Indian municipal engineers a unified design framework after decades of mixing IRC SP 50, IS codes, and ad-hoc municipal practice.
Coverage spans design philosophy (return periods 2-5 yr residential to 50-100 yr critical infra, separate vs combined sewer, climate uplift 10-30 %), rainfall analysis (IMD data sources, Gumbel/log-Pearson III frequency analysis, IDF curve construction, Chicago hyetograph, areal reduction factor for catchments > 25 km²), runoff estimation (Rational Method Q = C·i·A/360 with C values 0.20-0.95 by surface, time of concentration via Kirpich + FAA, Modified Rational with storage; SCS-CN for catchments > 200 ha; SWMM/MIKE URBAN/InfoWorks ICM modeling), storm sewer hydraulics (Manning's equation, partial-flow at d/D = 0.80, self-cleansing 0.6 m/s, max velocity 3-4 m/s concrete, hydraulic grade line, junction K-losses), catchment characterisation (DEM-based delineation, drainage districts 10-50 ha, imperviousness mapping, future build-out projection), network design (pipe sizing, slope, manhole spacing 30-100 m by diameter, drop manholes, RCC NP3 vs HDPE), inlets + catch basins (kerb opening + grated + combination, capacity at 50% clogging, spread T 1.5 m collector / 0.5 m underpass), outfalls + pumping (tide gates, non-return valves, storm water pump stations N+1 redundancy, energy dissipators), detention + SUDS (basin sizing, permeable pavement, bioswales, rain gardens, green roofs, mandatory rainwater harvesting), urban flooding management (NDMA Urban Flooding Guidelines 2010, vulnerability mapping, early warning systems with ≥ 30-min lead time, AMRUT 2.0 25-30 year master plans), and O&M + smart drainage (pre-monsoon desilting by 31 May, IoT sensors, citizen reporting, asset management).
Every Indian ULB managing storm water — municipal corporations, councils, nagar palikas — references this manual. AMRUT 2.0 storm water plans + Smart Cities Mission drainage upgrades cite it extensively.
The manual is a reference for specific design + operational decisions. Common lookup patterns: *What return period for residential drainage?* (Chapter 1: 2-5 years, with climate uplift 1.10-1.30). *What runoff coefficient for dense residential?* (Chapter 3: 0.65-0.80). *Manning's n for new RCC pipe?* (Chapter 5: 0.013 as-new, 0.015 design). *What design velocity?* (Chapter 5: 0.6 m/s self-cleansing minimum, 3-4 m/s max for concrete). *Manhole spacing for 600 mm pipe?* (Chapter 7: ≤ 30 m). *Spread T limit on arterial?* (Chapter 8: 1.0 m). *Tide gate freeboard at coastal outfall?* (Chapter 9: HTL + 0.5 m). *Drain-down time for detention basin?* (Chapter 10: 12-48 hours). *NDMA early-warning lead time?* (Chapter 11: ≥ 30 min). *Pre-monsoon desilting deadline?* (Chapter 12: 31 May).
InfraLens structures every chapter with key formulas at top, numeric values table, clause-level rules, practitioner notes, FAQs, and engineer's-notes prose at the end that captures the why + the field-failure modes. The FAQs mirror what AMRUT 2.0 + Smart Cities consultants actually get asked.
For DPR consultants: use this manual alongside IS 1742 (drainage), IS 12251 (surface drains), IS 458 (RCC pipes), IRC SP 50 (urban drainage), NDMA Urban Flooding Guidelines 2010, and AMRUT 2.0 Operational Guidelines. For ULB engineers: chapters 8 (inlets) + 11 (flood management) + 12 (O&M) are the most directly actionable for daily monsoon-season decisions.
10 common questions about this topic, answered by civil engineers.
The first dedicated Government of India technical manual for urban storm water drainage, published by Central Public Health and Environmental Engineering Organisation (CPHEEO) under Ministry of Housing and Urban Affairs. 1st Edition (2019) with AMRUT 2.0 + Smart Cities Mission updates referenced. Mandatory reference for AMRUT 2.0 storm water plans, Smart Cities Mission drainage projects, and ULB master plans across India.
Per CPHEEO 2019: 2-5 years for residential, 5-10 years for commercial/business, 10-25 years for arterial roads, 25-50 years for underpasses, 50-100 years for critical infrastructure (hospitals, metro, power). Apply climate-uplift factor of 1.10-1.30 — coastal/cyclone-prone cities use upper end.
Paved (asphalt/concrete): 0.85-0.95. Roof: 0.85-0.95. Dense built-up residential: 0.65-0.80. Medium residential: 0.40-0.60. Park/lawn (clay soil): 0.20-0.40. Park/lawn (sandy): 0.10-0.25. Open ground: 0.10-0.30. Always use area-weighted composite C for heterogeneous catchments + design for future imperviousness, not current.
0.013 for new smooth concrete (RCC NP3) pipe — 'as-new' value. 0.015 for design (accounting for biofilm + sediment buildup over service life). 0.011 for HDPE/PVC. 0.015-0.017 for brick-lined drains. 0.030-0.035 for grass-lined open channels. Designing to 0.013 means the pipe is hydraulically inadequate by year 5.
0.60 m/s at design discharge in storm sewers. Below this, sediment accumulates + drain clogs over time. Achieved by minimum slope: ~1 in 250 for 300 mm pipe; ~1 in 600 for 1000 mm pipe. Storm sewers should be designed at d/D = 0.80 (80% depth-to-diameter), not full pipe.
When gravity discharge is hydraulically infeasible — low-lying catchment behind tide-locked outfall, downstream of HGL constraint, or below normal river/lake water level. Common in coastal cities (Mumbai, Chennai, Kolkata, Kochi) + low-lying districts of inland cities. Design with N+1 pump redundancy + standby genset for critical applications.
Yes — CPHEEO 2019 + AMRUT 2.0 + Smart Cities Mission strongly recommend. SUDS (permeable pavement, bioswales, rain gardens, green roofs, retention ponds) reduces peak Q by 30-50 %, improves water quality, provides amenity. Up to 25 % capital subsidy available under AMRUT 2.0 for approved SUDS components.
25-30 year GIS-based storm water master plan, climate-adjusted, hydraulic-model validated (SWMM, MIKE URBAN, or InfoWorks ICM). Must include drainage district delineation, imperviousness mapping, network design, SUDS components, pumping stations, urban flood vulnerability assessment, + early warning system. Phase 1 underway for most Class-1 cities in 2026.
NDMA Urban Flooding Guidelines (2010) — vulnerability assessment, Early Warning System (EWS) with ≥ 30-min lead time, Incident Response System (IRS), post-event learning. Mandatory for Class-1 cities. Smart Cities + AMRUT 2.0 fund implementation. Mumbai July 2005, Chennai December 2015, Hyderabad October 2020 events all drove framework refinement.
By 31 May before monsoon onset (per CPHEEO 2019 + NDMA framework). Single highest-leverage O&M activity — done well, prevents 50-70 % of localised flooding complaints. Inlet cleaning minimum 2 cycles per year; pipe jetting full network in 3-5 year cycle; CCTV inspection every 3 years.