Project 9: Caring
for your stream
- Visit a stream. Study the water channels. Where does the water flow
quickly? Are there any signs of steep banks collapsing into the stream.
If possible ask a nature conservation official from your municipality
to advise you on where stream banks need to be protected.
- Collect cuttings of natural vegetation from a nearby area that has
sufficient natural growth. Cuttings should be made with a sharp knife
at a 45 degree angle, and be about 30 cm long. Plant the cuttings in
the river bank, so that 20 cm of the cutting is exposed and the butt
end is in permanently damp soil.
[Roots of cuttings stabilise banks and prevent erosion.]
- Where the bank is being undercut and collapsing into the stream it
may be necessary to build a rip-rap. Add rocks to the base of the eroding
bank so that they slope gently up to above the normal flood level.
The bank above the rocks will crumble into a more natural contour which
can be stabilised with vegetation later.
- Rocks can be used as deflectors to push the water flow away from
the banks. You will need to use large rocks on the point of the deflector.
This will protect the banks and provide a hiding and resting place for
The deflectors should not be more than a few centimeters above normal
water level so that it allows flood water to flow over it. This prevents
debris from collecting on the deflector at flood time and damaging the
- Dead trees can be wired alongside eroding banks to protect them.
Conifers are particularly useful for these tree revetments. The trees
are wired to logs buried in the banks for stability in flood seasons.
The trees protect the bank long enough for vegetation to stabilise the
- Many streams are seasonal. The flood scours the stream bed leaving
it rocky - with very little soil for plants to establish themselves
in. By building barriers to slow the water flow and trap sediments,
a silt bed can be formed and planted with stream bank vegetation. The
barrier can be made of stones to just above normal water level or a
fence of weldmesh, reinforced with metal stakes hammered 60 cm into
the bed of the stream. The weldmesh barrier should be low, just high
enough to catch debris. Protect the upstream side of the weldmesh barrier
with small stones heaped against it.
- Visit your barriers and bank deflectors and revetments several times
a year to repair any damage caused by floods.