olmstead suggests that while water prices on the whole do not seem to be higher in more arid regions water marketing is more prevalent in arid regions in a coasian sense the mere existence of the potential gains from trading water creates pressure for trade to occur so long as the property rights are clearly assigned in chile australia and the western us water trading has evolved in direct response to scarcity olmstead the national water code established in chile in separated water rights from land rights and allowed the water rights to be traded the response has been significant in the northcentral region bauer in australia water trading was introduced over the course of three decades beginning in with south australia