Drainage plays a key role in reducing the threat of inundation, waterlogging and salinity, all of which can have a detrimental effect on agriculture and the environment.
There are two types of drainage within the Goulburn Murray Irrigation District (GMID): surface drainage and subsurface drainage.
Surface Drainage
- Surface drainage enables the removal of excess water from the surface of the land. Primary Surface Drains are the ‘backbone’ of the GMID surface drainage network.
- They provide outfalls for GMW and private community surface drains and direct access for drainage water from farms.
- There is now extensive surface drainage coverage across the GMID, which includes a diverse mix of GMW, CMA, local government, and privately constructed drainage networks, as well as natural drainage courses and waterways.
- GMW surface drainage is more concentrated in the eastern GMID (the SIR).
- The different drain types include GMW Primary Drains, GMW Community Surface Drains, Local Government Drains, and Community Surface Drains (CSD).
- There are 3240 km of GMW drains (Primary and CSD) cross the GMID.
- These are owned and operated by community groups and private landholder drains serving multiple properties.
Subsurface Drainage
- Subsurface drainage provides controlled pumping from shallow groundwater systems to support effective salinity migration measures on local farms.
- In the Shepparton Irrigation Region (SIR), targeted subsurface drainage is provided by employing private groundwater pumping, public groundwater pumping and tile drainage in high-risk areas.
- Water tables commonly experience cycles of rising and subsiding. In the SIR, water table behaviour is driven by interaction of irrigation and rainfall.
- When wet climatic conditions exist, the shallow groundwater system is recharged and the regional water table rises. Where groundwater levels approach the surface, land salinisation and waterlogging of soils can threaten economic, environmental and social values.
The GMID Drainage Management Strategy
The GMID Drainage Management Strategy has been developed to provide a clear direction for the future management of irrigation drainage in the GMID.
You can view the full GMID Drainage Management Strategy or a summary of the GMID Drainage Management Strategy