The potential of satellite remote sensing for delineating coldwater streams in the driftless region of north-eastern Iowa

Keywords: coldwater streams, satellite remote sensing, object based image analysis, driftless region, Iowa,
Session Type: Virtual Poster Abstract
Day: Sunday
Session Start / End Time: 2/27/2022 03:40 PM (Eastern Time (US & Canada)) - 2/27/2022 05:00 PM (Eastern Time (US & Canada))
Room: Virtual 27

Abstract

Climate change is projected to alter the prevalent thermal characteristics of temperate coldwater streams which are crucial habitats for many types of biota. To protect these habitats, we must first know where they exist on the landscape. This study examines the potential of high-resolution satellite imagery combined with in situ observations of stream temperature and geomorphological characteristics to semi-automatically detect coldwater streams. Two watersheds were selected as pilot site for which multi-year panchromatic winter imagery was visually interpreted and the length of recorded coldwater streams was compared against the coldwater reaches mapping by Iowa DNR. In order to be sure of stream locations, two levels of interpretation were used as confidence intervals. The first level of confidence resulted in 25.39 miles of streams, while the second level (slightly less confidence in interpretation) resulted in 67.27 miles. These two levels combine for a total coldwater stream length of 92.66 miles which when compared to the existing DNR dataset showed a possible maximum difference of 78.28 miles. The DNR interpretation misclassified several coldwater stream stretches as warmwater. Visual analysis of high-resolution winter imagery made it clear that various site properties (channel width, canopy cover/density) as well as imagery characteristics (pixel size, sun angle at time of image acquisition) influence the interpretation of coldwater streams. These findings provide critical understanding of factors that will need to be addressed for developing a semi-automated coldwater stream detection and mapping method for identifying coldwater streams over the entire Driftless region of Iowa.