Two main concerns underlie recent changes in groundwater policies in some OECD countries: long-term aquifer depletion and surface water-groundwater interaction (e.g. McCarl et al., In the United States, concerns about groundwater pumping externalities are manifested in ongoing litigation over water resources and rapidly changing water management institutions (Hathaway, 2011; McKusick, 2002). Surface water-groundwater interaction has also been a major driver for changes in groundwater policy (Kuwayama and Brozovic, 2013; Palazzo and Brozovic, 2014); surface water flows are the subject of both transboundary legal challenges over river basin allocations and potential environmental impacts to instream habitat and other groundwater-dependent ecosystems (e.g. McKusick, 2002; Delaware River Basin Commission, 2008). These entitlements are the cornerstone of most regulatory approaches for groundwater management, "the central element of groundwater laws" (Mechlem, 2012), and have been found to be critical in reducing groundwater overdraft (Kemper, 2007).