Monitoring the Mega Drought and the effects it has on Reservoirs In Southwest Colorado using a Change Detection Analysis
Presentation Time: Wed, 08/03/2022 - 14:30
Keywords: NDWI, Landsat 8, Change Detection, Time Series, Remote Sensing
All across the Western portion of the United States water is an increasing topic of concern. A majority of the mainstream discussion revolves around Lake Mead and Lake Powel the two largest reservoirs in the United States. This project aims to shed light on the “Mega Drought” impacting three reservoirs in Southwest Colorado, McPhee Reservoir, Lemon Reservoir, and Vallecito Reservoir. The way the impact of the “Mega Drought” will be monitored is by generating a Normalized Difference Water Index (NDWI) every year from 2013-2021. The NDWIs were generated by using Landsat 8 Level 2 Collection 2 data. The data was compiled into ArcGIS Pro software. That data was compiled into a multidimensional raster format so a time series analysis could be performed as well as the generation of a change detection raster. To quantify the results of the NDWI sample points were generated to extract the pixel values. The results of this study showed that over the nine-year study that reservoir levels rose to the highest value in 2016 and have continued to fall to the year 2021. In 2021 all their reservoirs are registered with an average NDWI value that is classified as a moderate drought, non-aqueous surfaces. The results of this research are showing that these reservoirs in Southwest Colorado are decreasing in volume year after year. Mostly caused by decreasing snowpack, warmer spring and summer temperatures, and increasingly unproductive monsoon seasons.
