In Bibbullmun legal philosophy, land (*boodjar*) and water (*gabi*) are not separate commercial assets but an indivisible living entity: **Gabi Boodjar**.[1] Developed across forty-eight thousand years of empirical observation, Gabi Boodjar governance integrates surface catchments, superficial coastal aquifers, and deep granitic fracture systems into a unified regime of ecological responsibility.[2]
1. Subterranean Hydrology & Superficial Aquifers
Bibbullmun custodians recognised that surface wetlands are merely windows into expansive subterranean aquifers (*Gnarabup* / coastal unconfined aquifers).[3]
Customary laws strictly prohibited the excessive drainage, filling, or polluting of headwater marshes, recognising that groundwater depletion upstream directly caused the collapse of coastal freshwater springs (*moolyee*) vital for survival.[4]
2. Custodial Sanctuaries & Taboo Jurisprudence
Specific permanent deep-water pools—designated as *winaitch* (sacred or taboo)—were completely protected from daily hunting and recreational entry.[5] These sanctuaries served as critical biological seed reserves, enabling fish and waterfowl populations to repopulate surrounding river channels following seasonal droughts.[6]