Decentralization of environmental decision making has intensified the need for transdisciplinary and collaborative approaches to environmental problems. Currently, action is limited more by ineffective communication, fragmentation of responsibility, conflicting interests, and lack of trust than by lack of scientific understanding. A promising approach to lowering these barriers is joint fact-finding (JFF), a process for participatory inquiry in which scientists and citizens become partners in problem solving. This process requires facilitation by neutral, 3rd party information providers such as the USGS to depoliticize the use of science. Such "participatory experts" (Fischer, 1999) are critical intermediaries who help lay participants understand scientific findings, degree of certainty, and normative assumptions. Our research and implementation activities focus on this interface between science and policy. We are developing strategies for institutionalizing the role of the participatory expert in adressing complex, science-intensive issues. The USGS is uniquely suited to serve in this role. An important attribute of JFF is that it preserves the independence of the scientists and their commitment to scientific excellence, critical for a non-advocacy agency such as USGS. The long-term, regional-scale research conducted by the USGS, within an adaptive management context, can contribute to societal learning and sustainable decision making.