The Bilya (river systems) of the Bibbullmun Sovereign Nation constitute an integrated, continental-scale hydrological matrix that forms the structural foundation of customary law, seasonal migration, and ecological stewardship.[1] Rather than treating rivers as boundary markers that divide territories, Bibbullmun legal theory conceptualizes rivers as sacred living spines (*bilya-moort*) that bind clans together into shared catchment confederations.[2]
1. Catchment Confederate Architecture
The Bibbullmun territory encompasses eleven major river catchments: the Moore, Swan-Avon, Murray, Harvey, Collie, Preston, Capel, Blackwood, Warren, Frankland, and Denmark rivers.[3]
Each catchment operates under an integrated legal regime where upstream clans (*kardagur*) are held strictly accountable under customary law for maintaining water purity and flow volumes delivered to downstream estuarine custodians (*wardan-moort*).[4]
2. Waugal Hydro-Cosmology & Ecological Integrity
At the philosophical center of Bilya jurisprudence lies the **Waugal**—the ancestral serpent whose spiritual presence animates living freshwater.[5] Customary law mandates that any deliberate fouling, diverting, or dewatering of Waugal waterholes incurs severe ecological and spiritual sanctions.[6]