In cooperation with several federal and state agencies, the Information Center for the Environment (ICE) at the University of California Davis is analyzing the ability to cross-reference information linked to California's hydrography dataset (a modified form of the U.S. Environmental Protection Agency's River Reach File) to the new National Hydrography Dataset. California's Reach File contains a critical but non-standard foreign key that is essential to many research applications. Additionally, ICE plans to test, verify, and recommend enhancements to cross-referencing methods to improve the transfer of reach-code information from earlier hydrography datasets in California to the NHD.