The clearing of land for agricultural use has had a significant long-term effect on the state of our streams and waterways. Removing riparian vegetation, allowing stock to wander through wet areas and across stream beds, driving vehicles across streams and other activities that increase soil erosion and reduce vegetative buffer zones all serve to degrade the health of waterways. Water quality deteriorates due to the increased nutrients, sediments, herbicides, pesticides and bacteria entering the stream. In-stream habitats deteriorate through smothering and build-up of sediments, and through impacts on aquatic vegetation. Aquatic fauna suffer as suitable breeding sites disappear, their food sources are impacted and also directly through poor water quality.
LBCCG however recognises that early clearing and agricultural practices were essential for local development and it is pointless to blame long-gone forefathers for unforeseen present day issues. Indeed Baroon Pocket Dam is a very recent addition to the local landscape and the dam managers need to work with the local farming community. Through simple actions such as fencing off streams, installing off stream watering for stock and stream crossings for vehicle and/or stock, and replanting the riparian zones, there can be huge improvements in stream health. Riparian vegetation acts as a filter for runoff, slowing water flow and thus reducing erosive effects, and absorbing sediments, nutrients and other pollutants.
Riparian vegetation also provides shade to streams and regulates stream temperature. This acts to prevent excessive macrophyte and algal growths, which can cause major degradation of aquatic habitats and water quality.
Stock health and therefore production also benefit significantly through the availability of more accessible and cleaner water sources – they are not drinking water stirred up by their own movements or polluted by manure and urine – and through reduced risk of injury or even death through bogging or due to steep sided water channels.
Healthy vegetated riparian land also provides habitat for insect-eating birds and insect parasites that can help protect pastures and crops. The shelter and microclimate provided by riparian vegetation can help reduce death in newborn stock, reduce heat or cold stress, lead to improved pasture growth, reduce wind speeds which will assist growth of crops, and reduce wind damage to horticultural produce.
Deep-rooted vegetation may in some circumstances act to lower water tables along riverbanks, reducing the movement of salt and nutrients into streams from sub-surface flows.