## 13 Legal Approaches of Foreign Countries: The US, Australia, and in the European Union
Similarly, permission is necessary to appropriate groundwater in Idaho (Idaho Code $ 42-202). In Idaho, the Idaho Department of Water Resources(IDWR) is the state authority responsible for both administering and developing rules and regulations for not only surface water, but also groundwater. Through these mechanisms, Idaho establishes a comprehensive legal system for conjunctive management applying to \"areas determined to have a common groundwater supply\" (Idaho Administrative Procedure Act, Section 37).  
In Colorado and Washington, the doctrine of priority appropriation commonly applies to both surface water and groundwater. Colorado divides groundwater regulation and management into three categories: groundwater located in a nondesignated groundwater basin, groundwater located in a designated groundwater basin, and groundwater located in a Denver groundwater basin. Among them, especially the first type is presumed to be \"tributary\", so the groundwater falls within a single set of priorities with surface water (Colorado Revised Statutes SS 37-92-102, 2008). However, it may be determined to be \"nontributary groundwater\" because the presumption is rebuttable. In the case of nontributary groundwater, there is a restriction that the surface flow depletion should not exceed 0.1% of the groundwater withdrawal rate (Colorado Revised Statute SS 37-92-102, 2008). In Washington, the Washington Department of Ecology (WDE) administers the permit system for both surface water and groundwater (Revised Code of Washington $ 90.44.050, 2008). According to the groundwater code of Washington, the potential interrelationship between them is acknowledged (Revised Code of Washington $ 90.44.030, 2008). If it is determined that there is a \"significant hydraulic continuity\" between surface water and groundwater, they must be managed under a single set of priority rules or appropriation regime (Washington Administrative Code SS 173-549-060, 2008). Australia established regulatory/institutional grounds including relevant licensing systems for groundwater injection and recovery using rainwater, treated wastewater, and other types of surface water relatively early. Based on the concept of the public nature of water resources, authorities in Australia are in charge of the comprehensive regulation and management of water resources, from granting and distributing of the rights to rainwater and reclaimed water to the artificial injection, recovery, and distribution of such water [6; 14]. In terms of integrated management for surface water and groundwater, some areas in Australia have an allocation system similar to that of the US. In Australia, however, it is not the general approach to regulate the rights to surface water and groundwater together, which is common in some western states of the US. Moreover, in comparison with the cases of these states, the clear definition of property rights relating to ASR projects in Australia (e.g., rights to surface water) is lacking, which is a critical impediment to ASR in Australia [33]. Most European Union countries do not have an integrated domestic law regarding direct application and regulation of ASR/ASTR projects, with only a few exceptions: Spain and Switzerland. They individually establish and implement management policies based on the general laws concerning water resource management [6; 18; 30; 36]. Therefore, the issue of legal rights to surface water regarding ASWQE projects cannot be determined uniformly and accurately with only the relevant legal system itself.