A recent Spanish study examined effects of water markets as an institution that can substitute for growing economic risk caused by unreliable water in the Gaudalquivir Valley District in southern Spain (Calatrava and Garrido, 2005). Recent work from Mexico found considerable benefit in the use of water markets to promote water transfers from irrigators to urban users to address growing water scarcity in that country (Gastelum and Stewart, 2009). More recent work from both Spain and Mexico found that either water markets or reservoirs or both can reduce the risks of unreliable of water supply (Iglesias and Garrido, 2003, Unver and Gupta, 2003).