NASA Radar Assessments of Water Extent along River Levees

June 7, 2011, UAVSAR image of study area: This image is an RGB (HH, VV, VV) color composite with the high moisture class pixels (cyan) overlaid on top.

June 7, 2011, UAVSAR image of study area: This image is an RGB (HH, VV, VV) color composite with the high moisture class pixels (cyan) overlaid on top.

Team Location: Jet Propulsion Laboratory

Authors: Katrina Laygo, Austin Madson, Kevin O’Connell

Science Advisors/Mentors: Dr. Cathleen Jones, Benjamin Holt

Abstract: Every spring, precipitation and snowmelt in the central U.S. leads to high water levels in the Mississippi River and its tributaries, with concurrent flooding and levee damage a near-yearly event. In the spring of 2011, historic water levels led to extensive flooding from Mississippi County, Missouri, to southern Louisiana, necessitating the opening of three major spillways, including the Morganza Spillway north of New Orleans, which diverts water from the Mississippi River through the Atchafalaya Basin of central Louisiana and had not been used since 1973. There is value to NOAA, the agency responsible for flood prediction, and the U.S. Army Corps of Engineers, the agency responsible for flood control, in the application of remote sensing to flood mapping, both along the main rivers and along small tributaries that feed into them. Knowledge of water flow in the smaller tributaries and soil moisture in the watersheds are essential to the modeling that gives advance warning of flood times and locations. This project utilized high resolution radar (NASA UAVSAR), with a particular focus on LiDAR derived Digital Elevation Models to determine the accuracy and resolution with which flooding could be located by tracking the water extent along rivers and changes in the water extent between spring and normal levels in fall or early winter. Several UAVSAR data sets along the northern Mississippi River in April 2011 and along the lower Mississippi River in Louisiana in June 2011 were collected, which were analyzed for flood detection algorithm development as part of a previous part of this study. The current research focus was to determine the flood water height, develop an algorithm to detect areas of increased soil moisture, and to finalize flood map end products for decision makers based on an easily applied algorithm that utilize a standard analysis package for water extent measurement along waterways, which will be usable by non-experts with widely available software.

Video transcript available here.