In 2000, the Washington state legislature passed Engrossed Second Substitute House Bill 2867 (E2SHB 2867), which amended chapters 90.03 and 90.44 RCW. This bill expanded the definition of "reservoir" in RCW 90.03.370 to include "any naturally occurring underground geological formation where water is collected and stored for subsequent use as part of an underground artificial storage and recovery project." Projects of this type are more commonly known as "aquifer storage and recovery" or "ASR" projects. The legislation directed the department to adopt rules establishing the "standards for review and standards for mitigation of adverse impacts for an underground artificial storage and recovery project." The department of ecology promulgates this rule under the authorities provided in chapter 34.05 RCW and RCW 90.03.370.