Exmouth groundwater allocation planning

The Exmouth groundwater subarea allocation plan sets out our approach to managing groundwater resources of Western Australia’s North West Cape.
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The department recognises and acknowledges the Traditional Owners and custodians of the Exmouth Gulf and its surrounds, the Baiyungu, Yinikurtira and Thalanyji people. We recognise their deep and continuing connection to the land and waters of this region, and we pay respect to Elders past, present and emerging. 

Plan release information

The Exmouth groundwater subarea allocation plan was released in 1999 by the former Water and Rivers Commission. The plan outlines water allocation limits (how much water can be taken out of a resource for use), local water licensing policies, and monitoring programs that will apply in the plan area.

The plan sets water allocation limits for five groundwater subareas. Allocation limits manage water abstraction at a subarea or resource scale, while water licensing and monitoring requirements manage abstraction at a local scale. 

We set the allocation limits to manage how much water can be sustainably taken. This is influenced by the amount of groundwater needed to support water-dependent values. In Exmouth, terrestrial values include the cave systems and unique stygofauna of the Cape Range subterranean waterways, and places like Camerons Cave and Qualing Pool. There are near-shore marine ecosystem values including areas of mangrove and seagrass in shallow coastal waters.

Exmouth water allocation planning activities

In 2022, the Exmouth Gulf Taskforce (taskforce) was established by the Minister for Environment as an advisory body to provide recommendations on the conservation and enhancement of the key values of Exmouth Gulf and its surrounds. The taskforce is supported by our department.

Protection of the Cape Range subterranean waterways, and the groundwater-dependent ecological, cultural and social values, is a key interest of the taskforce and the Nganhurra Thanardi Garrbu Aboriginal Corporation (NTGAC). The NTGAC represents the Traditional Owners and custodians of the Exmouth Gulf and surrounds. 

We are evaluating the Exmouth plan and will be reviewing the water allocation limits with NTGAC, Water Corporation and the taskforce. We will work to better understand the ecological, social and cultural water values across the Exmouth area, and consider the latest climate data and projections to assess future groundwater availability. 

We will consider developing a new water allocation plan for the Exmouth subareas once this work is completed.

Aerial photo of the Cape Ranges and Exmouth Gulf
Aerial photo of the Cape Ranges in the background, transitioning into coastal plains and the Exmouth Gulf coastline in the foreground

Plan area

The Exmouth plan area is about 1,260 kilometres north of Perth covers 2,020 km2 of the North West Cape, on the western side of the Exmouth Gulf (see map below). It includes the Cape Range National Park, which is part of the Ningaloo Coast World Heritage Area. 

The climate of the Exmouth Peninsula is semi-arid, with hot summers and milder winters. Rainfall in Exmouth has a high natural variability, both monthly and year-to-year. The big rain events are brought both by tropical cyclones from the north and low-pressure systems extending from the south between January and July. The infrequent nature of these events means that there may be several consecutive years where rainfall is low. 

For management purposes, the area is divided into five groundwater subareas in the proclaimed Gascoyne Groundwater Area (see map): 

  • Exmouth North 
  • Exmouth Town 
  • Exmouth Central 
  • Exmouth West 
  • Exmouth South. 
Map showing the Exmouth groundwater subareas
Exmouth groundwater allocation planning covers five subareas used to manage the groundwater resources of Western Australia’s North West Cape

Groundwater resources

Groundwater from the karstic Cape Range limestone aquifer is the major freshwater resource in the Exmouth plan area. It is used to supply the town with drinking water and water for public amenities, domestic garden bores, tourism, defence, aquaculture and industrial uses.

The aquifer is a lens of fresh groundwater overlying saltwater in the Cape Range limestone formation (see conceptual cross-section below). The aquifer and the Cape Range subterranean waterways support unique and important values such as a rich diversity of stygofauna and troglofauna. 

The Cape Range subterranean waterways are listed in the Directory of Important Wetlands in Australia. The Cape Range Remipede Community at Bundera sinkhole and the Camerons Cave Troglobitic Community in the Exmouth townsite are threatened ecological communities recognised and protected under the Western Australian Biodiversity Conservation Act 2016

The high diversity of subterranean species also contributes to the Ningaloo Coast World Heritage listing, meeting the UNESCO criterion x: 

to contain the most important and significant natural habitats for in-situ conservation of biological diversity, including those containing threatened species of outstanding universal value from the point of view of science or conservation.

A conceptual cross-section of the Cape Range limestone groundwater system
A conceptual cross-section of the Cape Range limestone groundwater system of the Exmouth peninsula, from Cape Range east to the Exmouth Gulf

The deeper, confined Birdrong Sandstone aquifer is found at depths of about 1,000 metres and contains saline water. The Birdrong Sandstone aquifer is managed under the Carnarvon Artesian Basin water management plan.