1. Paleodrainage Evolution & The Cratonic Basin

The Gogulgar (the Avon River) represents the truncated western outlet of an ancient tertiary paleodrainage network that once drained the vast Archean granitic expanse of the Yilgarn Craton westward toward the Indian Ocean.^[1] Rising in the flat, chain-of-lakes country around Wickepin and Pingelly, the river flows north-north-west through Brookton, Beverley, York, and Northam before swinging sharply west through the deep gorge of the Darling Range to join the Brockman River and form the Derbal Yerrigan.^[1][2]

Under Ballardong customary law, the river forms the sacred axis of the Gogulgar country, shaped by the creation serpent who formed its deep, permanent river pools (Bilya pools).^[2][3] Unlike the coastal streams, the Avon exhibits extreme seasonal hydrological fluctuations: during winter floods, it flows as an energetic braided river, while during the hot summer months, the channel ceases to flow and is reduced to a series of isolated, deep refugia pools surrounded by dry gravel bars.^[3][4]

2. Refugia Ecology & The Walyunga Trading Confluence

Because the broader Yilgarn landscape lacks perennial surface water, the deep river pools of the Avon—such as Mile Pool, Burlong Pool, and Katrine Pool—served as vital ecological refugia during severe droughts.^[5] Ballardong custodians enforced strict customary laws prohibiting the contamination or depletion of these permanent water sanctuaries.^[5][6]

At Walyunga, situated where the Avon River breaches the Darling Scarp, archaeological excavations have documented thousands of years of continuous human occupation and high-volume stone tool manufacturing.^[6][7] Here, where fresh scarp springs met the river confluence, custodians gathered during autumn to knap quartz, silcrete, and chert transported by seasonal river torrents.^[7][8] The resulting blades and spearheads were traded northward through Yuat territory and eastward into the Goldfields, establishing the Avon River as a continental commercial corridor.^[8][9]

3. Alluvial Soil Management & Tuber Husbandry

The fertile alluvial terraces flanking the Avon River supported intensive botanical cultivation.^[10] Custodians managed vast meadows of wild yams (Dioscorea hastifolia, Warrine) and native lilies using traditional digging sticks (wanna).^[10][11]

Women turned the soil systematically during harvesting, loosening the heavy clay and burying bulb offshoots to facilitate vigorous seasonal regeneration.^[11][12] Jam tree woodlands (Acacia acuminata, Mangart) bordering the river were subjected to controlled low-intensity burning (Karl) to promote sweet edible gum exudes and attract mobs of western grey kangaroos (Yongka), which congregated on the sweet river flats during late summer.^[12][13]

4. Colonial Pastoral Clearance, Salinization & Unbroken Title

Following British exploration in 1830, colonial pastoralists established the settlements of York and Northam, seizing every permanent freshwater pool along the Avon River for sheep flocks.^[14] Extensive clearing of native deep-rooted perennial vegetation by settlers initiated catastrophic secondary salinization, transforming previously fresh river sections into hypersaline drains—a ecological disaster unknown under customary Bibbullmun stewardship.^[14][15]

Ballardong warriors under leaders including Doodjep and Ningina fiercely defended their ancestral watering places, launching tactical strikes against pastoral outposts before being violently suppressed by British military detachments.^[15][16] Despite severe dispossession, Ballardong families preserved their spiritual, legal, and custodial connection to the Gogulgar across generations.^[16][17] Under the doctrine established in Mabo [No 2] and modern international declarations, Ballardong sovereign rights across the Avon River basin remain permanent, living, and unceded.^[17][18]