Description: The Stream Environment Zone (SEZ) map for the Lake Tahoe Basin was created by compiling the best available information on hydrological features in the Basin, including a wetlands map created from high-resolution LiDAR and imagery, thematic layers for riparian vegetation, fens, and seeps\springs from the U.S. Forest Service, soils from the U.S. Natural Resources Conservation Service (SSURGO), and 100-year flood zones (FEMA). These layers capture specific elements of the intended classification and also leverage resources previously committed to mapping projects in the Lake Tahoe Basin. All pertinent layers were compiled into a single, seamless map using eCognition (Trimble), state-of-the-art image classification software that permits efficient and rapid analysis of large volumes of data in multiple formats, including multispectral imagery, LiDAR, and thematic GIS datasets. This functionality was especially helpful in refining the initial SEZ map, permitting spectral classification of available WorldView-2 imagery (leaf on, acquired in 2010) when the thematic datasets could not capture individual classes in their entirety and also facilitating smoothing of the final product. The SEZ classification was designed with 7 primary classes: Fens, Forested, Freshwater Estuarine, Lacustrine, Meadows, Riverine, and Seeps\Springs. Two classes were further divided into sub-categories: Lacustrine into permanent water bodies (Lakes and Ponds) and beaches along Lake Tahoe (Lake Tahoe Beaches); and Riverine into several channel types (Confined Channel vs. Unconfined Channel). Note, however, that no systematic, reliable criteria could be identified for differentiating Unconfined Channels from other riparian classes (e.g., Meadows and Forested), so this class was not used in the final classification.Note that the SEZ classes should be considered potentialaquatic features; because some of the features were developed from soils and LiDAR-derived topographical and hydrological models, they do not necessarily reflect actual land-use conditions. This reality is particularly evident in the Forested class, which encompasses developed land uses (e.g., roads, buildings) south of Lake Tahoe and in other suburbanized parts of the basin.
Service Item Id: fb71739721fa4e49a4280fe608ae97d1
Copyright Text: This SEZ map was compiled by the Spatial Informatics Group (SIG). Funding was provided by the U.S. Bureau of Land Management through the Southern Nevada Lands Management Act capital program.