Stream Environmental Zones (SEZs) Review

Wetlands play a critical ecological role and provide a wide range of ecosystem services. Foremost among the many functions they provide are maintaining water quality, allowing groundwater infiltration, trapping sediments, serving as hotspots of biological activity and biodiversity, and playing a critical role in the cycling of carbon and nutrients. Their scenic beauty and recreational value to people is also immense. The Tahoe Regional Planning Agency (TRPA) defines Stream Environmental Zones (SEZ) as: “Generally an area that owes its biological and physical characteristics to the presence of surface or ground water." This definition includes perennial, intermittent, and ephemeral streams; wet meadows, marshes, and other wetlands; riparian areas, beaches, and other areas expressing the presence or influence of surface or ground water. The TRPA is tasked with preserving existing SEZ areas and restoring disturbed lands. The goal of this project is to critically review the SEZ model and standards currently being employed by TRPA in the context of the latest scientific understanding of wetland ecosystem function to ensure TRPA continues to evaluate and manage these areas appropriately in the future. There are five specific outcomes associated with this review: 1) the development of an updated conceptual model for SEZ function; 2) a brief that evaluates the continued utility of the SEZ model; 3) a brief that evaluates the utility of quantifying SEZ “function” through gross measurements of SEZ area; 4) a brief that reviews historic mapping of SEZs in the Tahoe basin and reviews the utility of different approaches; and 5) a review of the potential impacts of ongoing changes in climate to SEZ in the Tahoe basin and the ecosystem services they provide. These results will be presented to the TRPA at the completion of the project.


Contact for more information: Alison Toy; natoy@ucdavis.edu

Related Documents:

Task Order

UCD WO5, UNR WO1, USGS WO3:   SEZ Threshold Review

"Tahoe Stream Environmental Zones Review"