Management of high groundwater levels, waterlogging of land and increased surfacewater flows in the flat landforms of the Wheatbelt is required to maintain the land as productive farmland or areas of environmental or social value. With 10% of the wheatbelt classified as 'salt effected' (see managing salinity), hard engineering solutions have been used in the past with a variety of results.
Deep drainage is seen by many land managers as an effective tool to reduce the groundwater levels, eliminate waterlogging and move excess water away from productive land. To affect this, many hundreds of kilometres of drains have been constructed in regional areas of Western Australia each year.
However, undertaking formal engineering designs to manage surfacewater and groundwater flows and minimise the impact on the downstream environment is essential. What needs to be considered is:
- The change in agricultural production
- How the design will deal with flooding (keeping surfacewater and groundwater separate)
- The impact on the downstream environment, with increased flows and potential acidification and contaminants.
- Impact on infrastructure such as towns, roads and rail.
To assess the suitability of various engineering options, the department undertook the Engineering Evaluation Initiative between 2001 and 2009. Much of this work is currently published with links below. The work lead to the development of the Policy framework for inland drainage, 2012 which was developed in collaboration between the Departments of Water, Agriculture and Food as well as Environment and Conservation (now Parks and Wildlife) with direction from the Wheatbelt Drainage Council.