Land Capability Assessment Process

Undertaking a Land Capability Assessment (LCA) for the treatment and disposal of wastewater in unsewered locations on a property involves a methodical process to obtain a site specific solution.

Different locations typically have different considerations in terms of the sites ability to dispose of wastewater.  For example, property sizes vary across different locations with a wide variety of underlying soil types which impact on the optimum wastewater treatment level and method of wastewater disposal.

Once client approval has been obtained a typical LCA process involves the following steps:

• Complete a desktop review which includes obtaining information from relevant statutory planning documentation, additional information including underlying site geology, indicative soil type and topographical information (site slope, proximity to water courses and indicative vegetation cover).
• Complete a site survey including soil testing to a minimum depth of 1500mm to determine soil structure and characteristics. A soil sample may be taken to determine more specific characteristics including pH and sodicity.  The location and placement of wastewater treatment plants and location of wastewater disposal areas are determined in consideration of existing vegetation cover, slope and any existing buildings and other infrastructure.
• Once the information has been compiled a site specific solution is recommended in the report for the client.

Additionally, some sites may be located in areas that are designated potable water catchments which require specific considerations including any Domestic Wastewater Management Plan (DWMP) and the report is normally referral to statutory water bodies.  In some cases, a local government authority may require a soil permeability test using a constant head permeameter to determine a site specific soil infiltration rate.  An LCA will vary in cost  depending upon the site specific considerations.