Paradox of the moving boundary: Legal heredity of river accretion and avulsion

John W. Donaldson
Department of Geography, Durham University, Durham, UK; w.donaldson@durham.ac.uk

ABSTRACT: International boundaries -€“ the divisions between state jurisdictions -€“ are characterised in law by their inherent rigidity. Yet recent research has revealed that well over one-third of the total length of international boundaries follow rivers or streams that are inherently dynamic natural features. The tension between legal staticity and fluid dynamism manifests along international river boundaries both in terms of the problematic definition of the line itself and the disparity in water management regulations. The actions of accretion and avulsion have been used to resolve disputes over river boundary movement since Roman times, but they contain an inherent paradox. Tracing the heredity of these two legal mechanisms, this paper will expose that paradox by focusing on the relationship between boundary and water. State practice will reveal how the continued application of these mechanisms is reinforcing a land bias in international law that becomes problematic when addressing a dynamic fluid resource that is concurrently divided and shared. Rather than emphasising the rigidity of jurisdictional division, this paper will suggest that deterring the risks inherent in the definition of river boundaries requires challenging some of the foundational legal tenets of territorial sovereignty; tenets that continue to influence the development of international water law.