The Seoul Rules on International Groundwaters

(Adopted by the International Law Association at the Sixty-Second Conference Held at Seoul in 1986)

Article I: The Waters of International Aquifers*

The waters of an aquifer that is intersected by the boundary between two or more States are international groundwaters if such an aquifer with its waters forms an international basin or part thereof. Those states are basin States within the meaning of the Helsinki Rules whether or not the aquifer and its waters form with surface waters part of a hydraulic system flowing into a common terminus.

Article II: Hydraulic Interdependence

1. An aquifer that contributes water to, or receives water from, surface waters of an international basin constitutes part of an international basin for the purposes of the Helsinki Rules.

2. An aquifer intersected by the boundary between two or more States that does not contribute water to, or receive water from, surface waters of an international drainage basin constitutes an international drainage basin for the purposes of the Helsinki Rules.

3. Basin states, in exercising their rights and performing their duties under international law, shall take into account any interdependence of the groundwater and other waters including any interconnections between aquifers, and any leaching into aquifers caused by activities and areas under their jurisdiction.

Article III: Protection of Groundwater

1. Basin states shall prevent or abate the pollution of international groundwaters in accordance with international law applicable to existing, new, increased and highly dangerous pollution. Special consideration shall be given to the long-term effects of the pollution of groundwater.

2. Basin states shall consult and exchange relevant available information and data at the request of any one of them.

(a) for the purpose of preserving the groundwaters of the basin from degradation and protecting form impairment the geologic structure of the aquifers, including recharge areas; (b) for the purpose of considering joint or parallel quality standards and environmental protection measures applicable to international groundwaters and their aquifers.

3. Basin states shall cooperate, at the request of any one of them, for the purpose of collecting and analyzing additional needed information and data pertinent to the international groundwaters or their aquifers.

Article IV: Groundwater Management and Surface Waters

Basin states should consider the integrated management, including conjunctive use with surface waters, of their international groundwaters at the request of any one of them.

* The term "aquifer" as here employed comprehends all underground waters bearing strata capable of yielding water on a practical basis, whether these are in other instruments or context called by another name such as "groundwater reservoir", "groundwater catchment area", etc., including the waters in fissured or fractured rock formations and the structures containing deep, so-called "fossil waters".