The erosion of topsoil from vegetation
clearance and earthwork sites is a problem
throughout much of the Wellington
region.
The combination of high rainfall, hilly terrain,
clayey soil and underlying geology means that
if soil is disturbed during site development, it
is easily washed away by rainfall. Thousands of
tonnes of soil are lost this way in each rain event,
and cause a range of problems in our waterways.
A typical hilly subdivision site in the Wellington
region, once cleared of vegetation could lose up
to one thousand tonnes of soil per hectare per
year. While individual sites may not export a
large quantity of sediment, if there are multiple
subdivision sites in a catchment the overall effect
on the environment can be signifi cant.
Soil entering a waterway from your site
can cause problems for several kilometres
downstream, the most obvious being colour
change1