Technical Evaluation of Public Access Alignments for the Giacomini Wetland Restoration Project, Part 1: Resources Study

Kamman Hydrology and Engineering, Inc.

Brief Description: A report evaluating the potential impacts to existing and potential future hydrologic cultural, amd biological resource conditions that would result from implementation of 18 potential public access alignments. Full Description: The National Park Service (NPS) is evaluating a range of possible restoration alternatives for the proposed wetlands restoration project at the Giacomini Ranch in Marin County, California. The Giacomini Ranch is located in the southern portion of the Tomales Bay watershed. The potential for incorporating public access within the Project Area is an important issue that was raised during the project scoping. During scoping, several potential public access concepts or alignments were proposed either by members of the public, the NPS, or by other local agencies such as the County of Marin. The intent of this Study is to inform the public and the NPS on potential resource impacts associated with these alignments, so that fully informed decisions can be made on options for future planning studies. This technical evaluation addresses the potential impacts to existing and potential future hydrologic, cultural, and biological resource condition that would result from implementation of 18 potential public access alignments, including perimeter/loop pathways, spur/point access, and/or viewing platforms/overlooks. Potential trail alignments and platform/overlook location included for study were based on concepts discussed by the NPS, the County of Marin, the West Marin Paths study, or the public through comments both during and outside of the scoping period. The potential impacts of each potential trail alignment or platform/overlook location were analyzed for two possible restoration concepts: Alternative A and Alternative C. Impacts were considered for both 1) existing conditions and 2) potential future conditions of the restored wetlands and unrestored areas. The NPS intends to use the information from this technical evaluation to determine those potential public access alignments and platform/overlook locations that have the least environmental and cultural resource impacts. In addition, this evaluation assesses whether alignments might pose conflicts with the project purpose, goals, and objectives. While every effort has been made to identify all potential resource impacts associated with these potential public access opportunities, additional impacts could be discovered during the technical feasibility analysis or production of the environmental document that might change how a particular alignment or siting is evaluated in the future.