Watercourses in the Northern and Yorke region are an important part of the landscape. The water that flows through a creek or river is precious and so is the land adjacent to it, called riparian land. This land is often the most productive for agriculture, with better quality soils and longer periods of moisture retention.
This land is also important for natural ecosystems, providing a diverse range of habitats, food types and refuge for native plants and animals. It also provides corridors for wildlife in highly cleared landscapes, with many native plants found only in riparian areas and many native animals using these areas as an essential part of their lifecycle.
Watercourses need careful management. While they are an environmentally-important and agriculturally-productive part of our landscapes, they are also vulnerable to being damaged by cultivation, grazing, weed invasion, spray drift from chemicals and natural events such as floods and fire. Every watercourse is unique, and careful planning is needed to identify the issues, objectives and the best strategies.
Benefits of good watercourse management
- Riparian lands serve as corridors between tablelands and lowlands, and enable essential seasonal movement of species between the two. Poorly managed riparian areas can upset important biological balances.
- In drier environments, riparian lands act as refuges for plants and animals during drought or fire. When better times return, these lands become reservoirs that species can recolonise around.
- Healthy riparian vegetation helps maintain good habitat for aquatic animals, including insects and the fish that feed on them. The roots of vegetation provide essential habitat by protecting overhanging banks, while large branches or trunks that fall into the water also provide shelter from predators and a diversity of flow speeds. Streams are also used for recreational fishing and can be an important source of income for land holders and regional communities.
Improved water quality
- Good management of riparian land can decrease the amount of soil and nutrients moving downstream from cultivated fields. Riparian vegetation can absorb these nutrients and help reduce light and temperature of stream ecosystems, which can control growth of nuisance plants and algae in downstream rivers.
- Deep-rooted riparian vegetation may also lower water tables along riverbanks, reducing the movement of salt and nutrients into streams from sub-surface flows.
Maintaining land quality
- If an area has been over-cleared or intensively development and is therefore not well-vegetated with deep-rooted plants, heavy rains can cause floods, strip topsoil from floodplains and accelerate bank erosion. Well-vegetated stream banks and more resistant to under-cutting and slumping and help stabilise riverbanks and protect them in times of flood.
- Protecting river banks and channels from excessive erosion also helps prevent rivers from changing their course and forming new meanders or flood channels. Head cutting and meanders can pose risks to roads, bridges and buildings.
- Controlling access of stock to riparian land helps to prevent soil erosion and reduction of water quality for downstream users. It also lowers the risk of injury or death to stock falling down steep riverbanks or becoming bogged in deep mud. Evidence also suggests that stock exposed to polluted drinking water have higher risk of bacterial infection, slower growth rates and less inclination to drink, therefore lowering production rates.
- Vegetated riparian areas reduce wind speeds and this can assist growth and production of crops, as well as reduce wind damage to valuable horticultural produce. The shelter and microclimate created by riparian vegetation can reduce heat and cold stress in animals, therefore reducing death in newborn or newly shorn sheep and improving growth and productivity.
- Healthy, vegetated riparian land provides habitat for insect-eating birds and insect parasites that can help to protect pastures and crops from damage.
- Anecdotal evidence suggests that well maintained riparian frontage increase the capital value of a property by up to 10%.
- Land holders can use riparian land to diversify their business, such as through hay or stored forage production, growing specialist crops or combining riparian management with agroforestry production.