Hydrology Survey Report: Runoff, Peak Discharge, and Design Rainfall
A hydrology survey report quantifies surface water behaviour at a site — design rainfall, runoff volume, peak discharge, and time of concentration — for stormwater sizing, culvert design, and rainwater-harvesting overflow structures. Rain GEO SAT's Expert workspace assembles this report using satellite rainfall, DEM-derived catchment, and CN-based runoff estimation.
Report contents
Every hydrology report includes design rainfall (typically 1-in-10-year, 1-hour intensity from IMD IDF curves), catchment area from DEM delineation, runoff volume via SCS Curve Number, time of concentration via Kirpich, and peak discharge via the Rational Method.
- Design storm — 1-in-2, 1-in-5, 1-in-10, 1-in-25, 1-in-100-year events
- Catchment area — from Copernicus DEM (30 m) or Bhuvan Cartosat (30 m)
- Curve Number — from SoilGrids texture × land-use (Sentinel-2 NDVI)
- Time of concentration — Kirpich or SCS Lag equation
- Peak discharge — Rational Method (Q = 0.278 × C × I × A)
- Provenance table — data source, retrieval date, and formula version
When it is required
Municipal building permits for plots >2000 m². State PCB stormwater discharge NOC. IGBC/LEED SS credits for rainwater management. World Bank ESF hydrology annexes. CSR watershed-development baseline reports.
Frequently asked questions
- How is this different from a hydrogeological survey report?
- Hydrology focuses on surface water — rainfall, runoff, peak discharge. Hydrogeology focuses on subsurface water — aquifer, water table, borewell yield. Rain GEO SAT generates both from the same project.
- Which return period should I design for?
- 1-in-10-year is standard for urban stormwater drains. 1-in-25-year for major culverts. 1-in-100-year for critical infrastructure and dam spillways.
Ready to apply this on your site?
Rain GEO SAT calculators use IMD, NASA POWER, Open-Meteo, and CGWB data to deliver engineer-grade rainwater harvesting and groundwater recharge designs.
Related guides
- Rainwater Harvesting Calculator: Rooftop Yield, Tank Volume & Recharge Sizing
- Borewell Recharge Design: Sizing, Filter Media, and CGWB Compliance
- Groundwater Recharge Design: Pits, Trenches, Shafts, and Percolation Tanks
- Stormwater Drain Design: Rational Method, IDF Curves, and Peak Discharge
- Watershed Analysis Guide: Delineation, Flow Direction (D8), and Recharge Prioritisation
- ESG Water Reporting: GRI 303, CDP Water Security, and BRSR Compliance