Water Velocities around Water Plants in Chalk Streams

Water velocities were measured around water plants in a chalk stream. Low velocities ($500\ {\rm mm}\.\ {\rm s}^{-1}$) was found in open water and above weed beds. An indirect method of estimating mean water velocity through weed beds, using discharge measurements, revealed velocities between 40 and$140\ {\rm mm}\.\ {\rm s}^{-1}$, while open water velocities ranged between 200 and$370\ {\rm mm}\.\ {\rm s}^{-1}$. The significance of the velocities is discussed.