Prepared for the SFPUC by EDAW, Inc., September 2004, this report sets the stage for subsequent reports that access environmental impacts, develop a monitoring program, and detail the regulatory process for various alternatives. The September 2004 Final Version was revised based on public comments and scientific peer review.  We would like to thank members of the Lake Merced Task Force and Dr. Alex Horne, Professor of Ecological Engineering at UC Berkeley for their review and critique of this analysis. Greg Bartow of the SFPUC was the Project Manager for this report.