Wikipedia
Silala
The Silala is an aquifer and river arising from springs in Bolivia, and flowing into Chile.
The division of the flow from this water body has been a matter of controversy between the two nations, Chile claiming that the present route makes it an international river, while Bolivia denies there is a river and asserts that the Silala ‘springs’ would not flow to Chile if not for the construction of canals over a hundred years ago.Gabriel Eckstein and Brendan M. Mulligan Water Resources Development, Vol. 27, No. 3, pp. 595-606, September 2011. Posted on SSRN September 1, 2011 link
Accessed 8 April 2011