Formal trading of water rights beyond the users sharing one concession was allowed in 1999 but remains rare. For example, in the Segura Basin formal water trading between 2001 and 2005 amounted to less than 1% of total water consumption (Garrido and Calatrava, 2010). Some RBAs have also have set up water banks to encourage the trading of seasonal water rights during drought periods with some success, helping to avoid water rationing in such periods.