Riparian zones are the areas beside streams. These areas are sometimes reconstructed or improved to provide habitat for fish and other aquatic life and to stabilise banks against erosion. This riparian restoration can also have benefits in improving the quality of the water.

Riparian restoration may involve modifying the flow of the stream and re-establishing plants beside the stream. These help to slow the flow of the water in the stream, which helps prevent erosion. It also allows time for microorganisms present to reduce any excess nitrogen in the water. This nitrogen can come from fertiliser run-off or animal waste. If the stream runs along a road, residues from car exhausts can also pollute the water. The excess nitrogen in the stream can increase the growth of weeds and algae, which can lower the oxygen levels in the water and has disastrous consequences on any aquatic life.

Nature of science

Riparian restoration is a good example of how evidence-based scientific conclusions can result in direct action that can have a positive effect on the community.

Reducing stock access to streams and planting native plants along the bank are often all that is needed to change the water from murky and polluted into a crystal clear stream teeming with life. Many councils around the country are encouraging people to create a riparian strips along waterways, and many provide grants to help with the cost of buying plants. Contact your local council to find out what is going on in your area.

    Published 9 September 2008