Watercourses are an important part of our landscapes. 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.
Take a look at this video on the Barossa Improved Grazing Group website to see rehabilitation works being done on a trial site at Moculta. There is a winter stream running into the North Para River that gets boggy in winter. Four vegetation options are being trialled to see which will most improve bank stabilisation: native grasses, shrubs and ground covers, hardy reeds and rushes. They have also set up a control area with restricted stock access. This dairy farm has had the site fenced 10 metres either side of the watercourse for 250 metres, to prevent stock access and pugging of the soil by cows.
Activities to protect watercourses and to allow for rehabilitation works to be undertaken include:
- native habitat restoration
- soil and pasture management
- pest animal and plant management
- stabilisation and revegetation of degraded riparian areas
- stream bank stabilisation
- erosion control
- control and management of stock access to riparian areas
- dam management.
Benefits of managing watercourses
There are many benefits of managing and rehabilitating watercourses. These include:
- decreased erosion through revegetation of banks and in-stream structures
- improved water quality through reduced amounts of soil and nutrients flowing into the watercourse
- healthy aquatic and land-based ecosystems
- watercourse peak flow capacity is maintained, which reduces damage to property caused by the cutting and erosion of new channels in peak flow events
- decreased insect pest damage to pastures and crops by providing habitat for insect-eating birds and insect parasites
- increase in capital values of properties
- shelter for stock to reduce death in newborn or newly-shorn sheep and improved growth through reduction of heat or cold stress
- shelter provided by riparian vegetation reduces wind speeds assisting growth of crops and reducing wind damage
- opportunities for diversification of land use into agroforestry, growing firewood or specialist crops
- absorption and use of excess nutrients by riparian vegetation reduces growth of nuisance plants and algae
- deep-rooted riparian vegetation can lower groundwater tables reducing the movement of salt and nutrients into streams from sub-surface flows
- increased fish stocks by providing good habitat and food source for aquatic animals and insects
- provides refuge for native plants and animals during drought or fire, and a point for recolonisation of adjacent land
- wildlife corridors
- shade from riparian vegetation allows temperature and light differences in a watercourse, which provides greater habitat and ecosystem diversity and reduces the potential for algal blooms.