The SIFN Second Annual Workshop, Dec. 1-3, in Nashville, focused on the science needed to support instream flow standards. The workshop objectives were (1) to improve participants' understanding of information needs and approaches for developing useful, defensible, and protective instream flow standards; (2) to identify research needs to help meet participants' instream flow protection objectives. The workshop, organized around the Ecological Limits of Hydrologic Alteration (ELOHA) framework for developing instream flow standards, included technical sessions on standards and objectives, classification, information sources for setting flow-ecology relationships, and science to policy. Case studies were used to guide discussions. Three general themes emerged: (1) sufficient scientific understanding of flow-ecology relationships and tools are available for developing instream flow criteria; (2) science-based flow-ecology relationships serve to focus the stakeholder process of setting thresholds within the range of flow alterations; (3) over time, targeted monitoring and future research will provide additional information to improve standards and protection of aquatic resources. Presentations are attached. Utilize the attached agenda to identify a presentation's part in the workshop.