Examining environmental stress changes in response to climate change and land use dynamics in the Colorado River Basin over the past two decades

Keywords: Colorado River Basin; Land surface temperature; Evapotranspiration; Forest degradation; Landsat
Abstract Type: Poster Abstract

Abstract

The Colorado River Basin (CRB) is vital for the Southwestern US, supplying water to 40 million people and supporting wildlife habitats. Recognizing the impacts of climate change and historical drought, as highlighted by the US Department of Agriculture, is crucial for addressing water resources and environmental sustainability challenges in the region. We investigated spatiotemporal changes in forest and percent tree cover (PTC). Furthermore, we generated 30m resolution datasets for actual evapotranspiration (ETa), the enhanced vegetation index (EVI), and land surface temperature (LST) using all available Landsat images from 2001 to 2021. The Mann-Kendall test was employed to identify the CRB environmental changes over two decades. Ordinary Least Squares regression analysis quantified relationships among environmental parameters. The results revealed a forest degradation of 5,340km2 (3.82%), while only 739km2 (0.56%) underwent reforestation. The CRB experienced an average temperature increase of approximately 2.04°C over two decades, with 28.9% of the area exhibiting a significant upward trend, indicating an intensification of heat stress. Within significant change areas, the LST, ETa, EVI, and PTC changed annually by 0.187°C, -0.003mm, 0.004, and 0.02%, respectively. An annual increase of 0.186mm in ETa can be expected for each 1°C decrease in LST. Additionally, an annual increase of 0.062°C in LST can be anticipated for every 1% decrease in PTC. Conversely, a 0.0215mm increase in ETa can be expected for each 1% increase in PTC. Based on this perspective, we recommend that urban planners and decision-makers create policies to address environmental stress in the CRB under climate warming.