SIG’s Environmental Mapping Team mapped surface and submerged littoral substrates in Lake Tahoe, CA, NV from high-resolution satellite imagery using Object-Based Image Analysis (OBIA) analysis techniques. The derived substrate classes were translated into three fish habitats classes (spawning, feed and cover, marginal) in order to evaluate the attainment status with environmental standards related to nearshore fish habitat and to improve map products used for land-use planning and regulatory purposes. The results confirm previous satellite mapping efforts that feed and cover habitats and spawning habitats are limited in distribution to distinct areas around the lake, and that the Region is meeting TRPA fish habitat extent goals as currently defined. Our results support the use of high-resolution satellite data for discriminating substrate variation at a resolution sufficient to inform regional planning however additional investigation and data are needed to confidently discriminate aquatic vegetation features. Future efforts to improve estimates of changes in submerged substrate conditions over time may consider the use of higher spatial resolution imagery provided by unmanned aircraft systems. Results of this work were incorporated into the Fisheries Section of TRPA’s 2015 Threshold Evaluation.
