Drainage Density

This is a measure of how well a basin is drained by rivers.  The more extensive the network of streams, the higher the drainage density will be.  This measures how fast water drains into streams and rivers.  A simple calculation can be done for comparative purposes,

Drainage density = total length of all streams divided by basin area

A high drainage density indicates:

  • Water table is high
  • Rock or soil surface is impermeable
  • Thin vegetation cover
  • Quick surface run-off flow
  • Mature or well-established channel system


Drainage density is linked to stream frequency which is the total number of streams per area.

Low stream frequency is linked to low drainage density and coarse drainage texture.

High stream frequency is linked to high drainage density and fine drainage texture.