This is a part of the 2015 Fall VPS. For more VPS articles, click here
Category:åÊMonitoring Change for Resource Management
Project Team: Lake Tahoe Water Resources
Team Location: NASA Ames Research Center ÛÒ Mountain View, California
Dr. Brian Coltin (NASA Ames Research Center)
Dr. Juan Torres-PÌ©rez (Bay Area Environmental Research Institute)
As global climate change continues to escalate and droughts become more frequent and severe, it becomes increasingly necessary to monitor and regulate available water resources. Lake Tahoe (California/Nevada) is an important reservoir for tourism, local ecosystems, and drinking water. Its nearly 5 million annual visitors contribute at least $300 million to the local economy, making it one of California’s most popular attractions. Decreasing water levels are a concern for residents, the economy, and a number of endangered species that live on Lake Tahoe’s shores, such as the yellow cress. Current methods of monitoring lake levels, however, rely on depth gauges that require time-intensive fieldwork to retrieve data and are limited in their spatial coverage. Satellite imagery provides a far greater spatial extent while still providing regular measurements. Utilizing satellite imagery from the Landsat program, the Lake Level Automated Monitoring Algorithm (LLAMA) is a continuous detection lake level monitoring algorithm that uses a Modified Normalized Difference Water Index (MNDWI), thermal band analysis, and visible band reflectance values processed through Google’s cloud-based geospatial program Earth Engine. In addition to a lake area measurement, LLAMA is able to show measurements of turbidity and algae levels over any given lake worldwide. Thus, LLAMA has the ability to provide water managers near real-time data regarding the turbidity, algae, and water levels for any lake or reservoir of sufficient size via Google Earth Engine.