Runoff Curve Number (CN) Calculator

Calculate NRCS curve number CN from land use and hydrologic soil group (A-D). Runoff depth Q = (P-0.2S)²/(P+0.8S) where S = 25400/CN - 254. Required for SCS method hydrograph generation.

2D stress state at a point. All stresses in MPa.

σx — Normal Stress X (MPa)
σy — Normal Stress Y (MPa)
τxy — Shear Stress (MPa)
⚙ Mechanical Note: Results are based on standard textbook formulas and ISO/AASHTO references. Always verify critical designs with applicable codes (ISO 898, AASHTO 1993, AISC, Eurocode 3) and a qualified engineer.
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How It Works

Calculate NRCS curve number CN from land use and hydrologic soil group (A-D). Runoff depth Q = (P-0.2S)²/(P+0.8S) where S = 25400/CN - 254. Required for SCS method hydrograph generation

Each component has a specific meaning:

  • Land use — The land use recorded for the patient or scenario being assessed.
  • Hydrologic soil group — The hydrologic soil group recorded for the patient or scenario being assessed.

Note: Interpret the curve number result against the clinical thresholds and context described above.

How to Use

Enter the land use, hydrologic soil group for the patient or scenario you are assessing. Calculate NRCS curve number CN from land use and hydrologic soil group (A-D). Runoff depth Q = (P-0.2S)²/(P+0.8S) where S = 25400/CN - 254. Required for SCS method hydrograph generation. Use the curve number result to inform your clinical assessment.

Frequently Asked Questions