Esteban and Dinar (2013) conclude on the superiority of packaged sequenced policies instead of individual ones. Fuentes (2011) supports the use of economic incentives for water user associations to co-operate and enforce regulatory requirements on groundwater in Spain. Sophodeous (2012) reports that the relative successes that have allowed to slow down groundwater overdrafting in Kansas can be attributed to the multiple approaches that have been implemented, such as: the establishment of groundwater management districts, minimum stream flow regulations, metering and monitoring of resources, integrated resource planning, aquifer storage and recovery (ASR), a central water bank, and various water conservation programs.