(This measure has not been amended since it was introduced in the House on February 11, 2003. However, because action has occurred on the measure, the summary has been expanded.)Directs the Secretary of the Interior to study and report on the Rathdrum Prairie/Spokane Valley Aquifer for the purpose of preparing a model of the aquifer and establishing for the States of Idaho and Washington a mutually acceptable understanding of the aquifer as a groundwater resource. Authorizes appropriations.