This reference library provides authoritative values for drainage engineering calculations. All data is sourced from recognized engineering standards and publications, with citations provided for verification. Use the navigation to explore specific reference tables.
Manning's n Roughness Coefficients
75+ valuesOver 75 Manning's n values for closed conduits, lined channels, excavated channels, and natural streams. Essential for Manning's equation calculations.
SCS/NRCS Curve Numbers
60+ entriesComprehensive curve number lookup for the SCS runoff method. Includes urban, agricultural, and natural land uses with all Hydrologic Soil Groups.
Runoff Coefficients (C)
35+ valuesRational Method runoff coefficients by surface type and land use. Includes frequency adjustment factors for different return periods.
Standard Pipe Dimensions
80+ sizesStandard pipe sizes for RCP, CMP, PVC, HDPE, elliptical, and box culverts. Includes hydraulic properties and material specifications.
Soil Properties
12 texture classesUSDA soil texture classes, Hydrologic Soil Groups, Green-Ampt parameters, and hydraulic properties for infiltration analysis.
Primary Sources
- Chow (1959) Open-Channel Hydraulics
- TR-55 (1986) Urban Hydrology for Small Watersheds
- HEC-22 (2009) Urban Drainage Design Manual
- HDS-4 (2012) Introduction to Highway Hydraulics
- ASCE MOP 77 Design of Urban Stormwater Systems
- ASTM Standards Pipe specifications (C76, C507, F714, etc.)
- USDA NRCS NEH Part 630, Soil Survey Manual
All reference data includes specific citations. Users should verify values against current standards for critical applications.
Related Calculators
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