The catchment layer contains boundaries of watersheds where surfacewater drains to a common point into the sea or a major waterbody. Attributes include drainage division, basin (name and number), catchment name and drainage type. Related layers include sub-catchments, reservoir catchments and gauging station catchments.

This layer contains the linework of the water resource areas (surface water, groundwater and watercourse) which have been prescribed through legislation. This layer is maintained as the master linework of the prescribed areas within the state. Please refer to the metadata document for more information.

In response to water usage issues, certain areas within the state may be prescribed in order to control future water extraction processes. The prescription may be either area based or watercourse based (or in some area both eg Barossa). This layer contains the linework of the groundwater areas which have been prescribed through legislation. This layer is maintained as the master linework of the prescribed areas within the state.

Surface Water Management subareas for Western Australia were derived in consultation with the regional offices, and geometry is based on hydrographic catchments. Regional Department of Environment officers identified areas of similar management requirements to define boundaries or aggregations of hydrographic subcatchments. Regions with notable management concerns both currently and possibly in the future were identified to become management subareas. Management subareas will be used in the calculation of sustainable yields, flow rates and ultimately these calculations will be available for water allocation and natural resource management decisions. In addition, native vegetation clearing values have been calculated for each of the subareas located within the extent of the South-West region of Western Australia, for input into the allocation process. The Surface Water subarea data was developed in order to give a clear understanding of surface water availability and to provide management tools to make good water allocation and natural resources management decisions. Dataset was formerly known as Surface Water Management Subareas (DOW-021)

Surface Water subareas stored in WRIMS (Water Resource Information Management System). Surface Water Allocation Subareas for Western Australia were derived in consultation with the regional offices, and geometry is based on hydrographic catchments. Regional Department of Water and Environmental Regulation officers identified areas of similar management requirements to define boundaries or aggregations of hydrographic subcatchments. Regions with notable management concerns both currently and possibly in the future were identified to become management subareas. Allocation subareas will be used in the calculation of sustainable yields, flow rates and ultimately these calculations will be available for water allocation and natural resource management decisions. In addition, native vegetation clearing values have been calculated for each of the subareas located within the extent of the South-West region of Western Australia, for input into the allocation process. The Surface Water subarea data was developed in order to give a clear understanding of surface water availability and to provide management tools to make good water allocation and natural resources management decisions.

In response to water usage issues, certain areas within the state may be prescribed in order to control future water extraction processes. The prescription may be either area based or watercourse based (or in some area both e.g. Barossa). This layer contains the linework of the water resource areas (surface water, groundwater and watercourse) which have been prescribed through legislation. This layer is maintained as the master linework of the prescribed areas within the state.