Drainage Density Calculator

This calculator helps determine the drainage density (flow per unit width) needed for a given catchment area and rainfall intensity. It's essential for designing drainage systems in civil engineering and urban planning.

Input Parameters

Typical values range from 0.1 (impervious surfaces) to 0.9 (highly permeable surfaces)

Calculation Results

Calculation Formula

Drainage Density (q) = C × I × A

Where:
q = Drainage density (liters/second per meter width)
C = Runoff coefficient
I = Rainfall intensity (mm/hr)
A = Catchment area (sq. meters)

Results

Catchment Area: 0 sq. meters
Rainfall Intensity: 0 mm/hr
Runoff Coefficient: 0.6
Drainage Density (q): 0 liters/second/meter

Drainage Density Calculator Usage Guide

Learn how to use the Drainage Density Calculator and understand its applications in civil engineering

How to Use This Calculator

  1. Enter the catchment area in square meters. This is the total area that contributes water to the drainage system.
  2. Input the rainfall intensity in mm/hr. This represents how much rain falls per hour during the storm event.
  3. The runoff coefficient (C) determines how much water runs off the surface. You can adjust this based on the land surface type:
    • Paved surfaces: 0.8-0.9
    • Grass areas: 0.3-0.6
    • Soil (impervious): 0.6-0.8
  4. Click the "Calculate" button to compute the drainage density.
  5. The result shows the flow rate in liters per second per meter of drainage width needed to handle the stormwater.

Applications

This calculator is essential for:

  • Designing stormwater drainage systems
  • Calculating required pipe sizes and flow capacities
  • Urban planning for new developments
  • Managing flood risks in residential and commercial areas
  • Environmental engineering projects

Important Notes

  • This calculator provides a simplified estimation. Real-world designs may require additional factors like topography, soil type, and detention basin capacity.
  • The runoff coefficient can vary significantly based on local conditions and land use planning regulations.
  • For professional engineering projects, consult with qualified civil engineers and drainage specialists.