Shire of Coorow
|Area||~4,190 square kilometres, located ~290 km north of Perth.|
|Towns||Coorow, Green Head, Leeman and Marchagee|
|Average Temperature||Mean daily maximum temperature over 30 years 1990 – 2019 Coastal: 30°C (Jan) and 19.7°C (Jul); Inland: 36.5°C (Jan) and 18.5°C (Jul).|
|Annual Rainfall||Average annual rainfall over 30 years 1990 – 2019 Coastal: 443 mm; Inland: 350 mm (BoM 2020).|
|ABS Profile||Coorow ABS profile|
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Just over 1,000 people live in the Shire of Coorow, more than half of whom live in the coastal towns of Green Head (~300 people) and Leeman (~350 people, ABS 2016).
The population in the Shire of Coorow decreased by 4% between the last census in 2011 and the most recent census in 2016, and is projected to continue to decrease by a further 35% by 2031 (DPLH 2016).
Approximately 10% of residents of the Shire of Coorow were born overseas and approximately 3% are of Aboriginal and / or Torres Strait Islander descent.
Estimates of the resident populations as at 30 June are released annually for Local Government Areas (LGAs) in Australia by the Australian Bureau of Statistics. The estimates are generally revised 12 months later and final estimates are available after the following census. Visit the ABS website for further details.
The economy of the Shire of Coorow depends primarily on agriculture and related services. Local farming includes the production of cereal crops (wheat, canola, lupins, oats) and livestock (sheep and cattle). The region is home to a substantial, although now declining, fishing industry focused on rock lobster and wet-line fishing. Wildflower and coastal tourism is a growing area of the economy.
Land use in the Shire of Coorow is predominately nature reserves, agriculture, residential, industrial and commercial.
Priority conservation reserves includes Lesueur National Park, South Eneabba Nature Reserve, Alexander Morrison National Park, Pinjarrega Nature Reserve, Marchagee Nature Reserve, Capamauro Nature Reserve and Watheroo National Park.Namming Nature Reserve, Twyata Nature Reserve and Badgingarra National Park.
Watheroo National Park
The Watheroo National Park covers an area of 44,481 hectares and is located in the Shires of Coorow, Moora and Dandaragan. The national park is characterised by sand plains mostly dominated by heath and woodlands of Eucalypts.
Lesueur National Park
The Lesueur National Park covers an approximate area of 27,235 hectares and lies in the Geraldton Sand plains IBRA region. The national park is home to approximately 900 native plant species, with four rare or threatened species being recorded in the park including the Mount Lesueur Grevillea, Forrest’s Wattle, Lesueur Hakea and the Laterite Mallee.
Conservation reserves in the NAR
Alexander Morrison National Park
Declared in 1970, the Alexander Morrison National Park covers an area of 8 500 hectares and is located in the Shire of Coorow. It was named after Alexander Morrison (1849-1913) who was the first official Western Australian government botanist in the Bureau of Agriculture between 1897-1906.
The National Park is characterised by sand plains and low lateritic breakaway overlying sandstone and shale. The vegetation in the National Park comprises of sand heaths and small areas of low woodland and Mallee.
For more information about the park visit the DPaW website.
The coastline of the Shire of Coorow is dominated by Kockatea Shale which was formed in the triassic period from volcanic and sedimentary rocks. The Kockatea Shales consists of shale, minor siltstone, sandstone with deposits of calcareous and sandstone. Underlying the town site of Leeman is the Woodada formation formed during the mesozoic period from sedimentary and volcanic rocks. The Woodada formation comprises of fine to medium grained sandstone, interbedded with laminated siltstone. Lying east of the Kockatea Shale is the Lesueur Sandstone formation formed during the triassic period from volcanic and sedimentary rocks. The Lesueur Sandstone formation consists of very fine to coarse grained quartz sandstone, with subordinate granule conglomerate and minor siltstone. East of the Lesueur Sandstone formation is the Eneabba formation and Cattamarra Coal Measure. The Eneabba formation and Cattamarra Coal Measures were formed during the Jurassic period from volcanic and sedimentary rocks. The Eneabba formation consists of interbedded red-bed sandstone and siltstone. The Cattamarra Coal Measure consists of siltstone, shale, claystone, coal and sandstone.
The eastern portion of the shire is dominated by the Commberdale subgroup and south west terrain which forms part of the Yilgarn Craton. The Coomberdale subgroup comprises of sandstone, siltstone, dolomite rock and silica minerals. The south west terrain comprises of granite rock formed from igneous, metamorphic and gneiss rocks. The remainder of the eastern portion of the shire is underlined with the Billeranga sub-group, Yarragadee formation and the Cattamarra Coal Measures. The Billeranga sub-group was formed during the Mesoproterzoic era from sedimentary and volcanic rock. The Billeranga sub-group comprises of sandstone, siltstone, basalt and volcanic sandstone.
Much of the coastline of the Shire of Coorow comprises of deep sandy calcareous sands forming part of the complex dune system and some gravelly soils overlying limestone outcrops. The flat terrain along the coast comprises of saline and salt lake soils. To east of the salt lakes exists seasonal wet plains which are characterised by red calcareous clayey soils. The soils underlying much of the middle portion of the shire are described as deep siliceous sandy soils overlying undulating low hill rises with gravelly ridge crests and the occasional remnant dune. The eastern portion of the shire is dominated by lake systems comprising of saline and salt lake soils. Much of the areas surrounding the lake system is a plain with low dunes and depressions consisting of deep sandy and sandy earth soils.
Please go to the below link for more information on soil and geology in the region
Priority Fauna Species
Lesueur Sandplains (Geraldton Sandplains 2)
The Geraldton Hills is located in the LGAs in the middle portion of the region. This subregion is characterised by Proteaceous scrub heath dominates the undulating sandplain lying over the Permian and Cretaceous strata. Outwash plains associated with the drainage lines are dominated by York Gum and Jam woodlands. The lateritic mesas, sandplains, coastal sandplains and limestone are rich in shrub-heaths (Desmond and Chant, 2001c).
Ancient Drainage subregion (Avon Wheatbelt 1)
The Ancient Drainage subregion occurs in the eastern LGAs of the NAR. This subregion is characterised by Proteaceous scrub occupies much of the lateritic hills and outcrops. The alluvial plains associated with the drainage lines is dominated by eucalypts, Casuarinas, York Gum and Jam wattle woodlands (Beecham, 2001a).
Threatened Ecological Communities
Lesueur-Coomallo Floristic Community A1.2
The Lesueur-Coomallo Floristic Community A1.2 is an Ecological Community occurring within the Geraldton Sandplains IBRA Bioregion that has been identified as Endangered at State level, being endorsed in 2001. The Floristic Community has only been identified on one 31 hectare area within Lesueur National Park and is currently at threat from altered fire regimes, dieback (Phytophthora sp.), plant and animal pests, and mining.
The Lesueur-Coomallo Floristic Community A1.2 is described in Interim Recovery Plan No. 106 (pg 3) as being: Species-rich heath with emergent Hakea obliqua on sand with faithful species of Hakea obliqua and Beaufortia aff. elegans and constant species of Dasypogon bromeliifolius and Stirlingia latifolia over well-drained grey sand over pale yellow sand on lateritic uplands. Associated species include Allocasuarina humilis, Calothamnus sanguineous, Hibbertia hypericoides, Hypocalymma xanthopetalum and Schoenus subflavus.
Herbaceous plant assemblages on bentonite lake beds (Vegetation Types 1,2,3&7) and margins (Vegetation Types 4,5&6) of the Watheroo-Marchagee region
This TEC occurs within the Geraldton Sandplains IBRA Region. The following description is from the Herbaceous plant assemblages on bentonite lake beds (Vegetation Types 1,2,3&7) and margins (Vegetation Types 4,5&6) of the Watheroo-Marchagee region Interim recovery plan no. 108 (pg 2):
The plant community comprises herbaceous plant assemblages dominated by a combination of Triglochin mucronata, Trichanthodium exile, Asteridea athrixioides and Puccinellia stricta (Vegetation types 1,2,3&7) on the lake beds, and a combination of Podolepis capillaris, Angianthus tomentosus and Pogonolepis stricta (Vegetation types 4,5&6) on the lake margins, of bentonite lakes in the Watheroo-Marchagee region. These herbaceous plant assemblages are characterised by a dependence on a bentonite (saponite) substrate – naturally restricted to the lake beds and margins of perched, ephemeral freshwater playa lakes and claypans of the Watheroo-Marchagee region. Whilst most lakes comprise only herbaceous species, there are a number with varying densities of Casuarina obesa trees, and shrubs of Melaleuca lateriflora subspp. lateriflora and Acacia ligustrina.
Current Status: WA listed as Endangered.
Priority Ecological Communities
Lesueur-Coomallo Floristic Community M2 (Melaleuca preissiana woodland)
Woodland dominated by Melaleuca preissiana along sandy drainage lines, with faithful species of Anigozanthos pulcherrimus and constant species of Chamaescilla corymbosa, Petrophile brevifolia and Xanthorrhoea reflexa.
Category (WA) – Priority 1
For more information visit the DPaW website.
Primary and Secondary Coastal Dunes
Primary dunes (from low water mark) and secondary dunes. Valued for recreational, aesthetic and cultural reasons, along with the services provided for storm protection and habitat.
Seagrasses are flowering plants that complete their life cycle submerged in seawater. Western Australia has the world’s highest diversity of seagrasses, with 27 species occurring in shallow waters off the coast. Seagrasses form a vital component of marine ecosystems through their services as primary biomass producers, sources of habitat (including breeding and nursery areas) and dissolved oxygen, sediment traps, and nutrient cycling. Seagrass distribution is determined by a combination of shelter, sediment, turbidity, nutrient, temperature, current and tidal influences.
Extensive seagrass meadows occur in protected near-shore areas of the NAR, where clear water, low nutrients and sandy sea floors prevail, and are dominated by the long strap-like Ribbonweed or Strapweed (Posidonia spp) and the thin-stemmed Wireweed (Amphibolis spp).
Seagrass habitats are fragile and susceptible to damage and can take many years to recover from disturbance, such as physical damage/removal and shading due to algal blooms (as a result of increased nutrients), and sedimentation (due to dredging activities and erosion in catchment areas).
More information on seagrasses in Western Australia can be found in the following publications: Flowers of the Ocean: WA’s Expansive Seagrass Meadows; The Wonders of Weed Information Sheet; Fisheries Fact Sheet: Seagrasses; Establishing Reference and Monitoring Sites to Assess a Key Indicator of Ecosystem Health (Seagrass Health) on the central west Coast of Western Australia (see references).
Jurien Groundwater Area
The Jurien Groundwater Area spans over 5,000 km2 of land and has a total groundwater availability of around 84 million m3/year. Groundwater usage is low, with 21 per cent of resources allocated. There are also signiﬁcant amounts of groundwater available in the Parmelia/Leederville formations. The superﬁcial formation contains important resources near the coast, although the quality and quantity of groundwater is variable (DoW, 2010).
For information on the allocation plan click here.
Gascoyne Groundwater Area
The Gascoyne Groundwater Area extends north to Kalbarri and bounds the Arrowsmith Groundwater Area east to pastoral country. The largest groundwater aquifer occurs in the Yarragadee Formation, which has an estimated yield of 22.5 million m³/year (NACC, 2005). Groundwater from fractured rock aquifers in the eastern, inland part of the region is predominantly saline and poor yielding. This region of the Gascoyne Groundwater Area falls under the Carnarvon Artesian Basin Allocation Plan.
Arrowsmith Groundwater Area
The Arrowsmith Groundwater Area spans approximately 10,300 km2 of land and currently has a total groundwater availability of around 151 million m3/year. The largest groundwater aquifers occur in the Yarragadee and Parmelia formations that together receive over 80 per cent of the total direct rainfall recharge, although the quality is variable. The Superﬁcial formation is an important resource near the coast, and similarly to the deeper aquifers, the quality and quantity of the groundwater is variable.
For information on the allocation plan click here.
Yarra Yarra and Monger Lakes
Drainage Basin Length (km) Catchment Area (km2) Average Stream Salinity (mg/L) Key Characteristics Yarra-Yarra and Moore-Hill 350 17,700 >35,000 Yarra Yarra Lake is the terminal point for an extensive chain of salt lakes. The major lakes in the system include Nullewa Lake, Weelhamby Lake, Mongers Lake, Lake Goorly, Lake DeCourey and Lake Hillman.Approximately 42 % of the Yarra Yarra Drainage Basin is in the NAR. Due to the basin’s ﬂat terrain, drainage is generally uncoordinated, with each lake having its own internal drainage system. However, in wet years the lakes overﬂow along a broad drainage line, ending up in Yarra Yarra Lake. It is uncertain if there is a surface or groundwater connection between Yarra Yarra Lake and the Coonderoo River, a tributary of the Moore River.
Drainage Basin Length (km) Catchment Area (km2) Average Stream Salinity (mg/L) Key Characteristics Moore-Hill 288 13,450 3000-35000 The Moore River’s eastern reaches (Moore River East) which originates near Dalwallinu, and northern reaches (Moore River North) commences east of Coorow. The major tributaries are the Coonderoo River and Gingin Brook. The Moore River enters the ocean at Guilderton and the estuary is only open to the ocean for a few weeks each year.