USING TERRESTRIAL LIGHT DETECTION AND RANGING (LIDAR) TO MONITOR BANK EROSION ALONG BIG BEND ON THE MISSOURI RIVER (MNISOSA WAKPA)

The Lower Brule Project focuses on erosion along the Big Bend of the Missouri River, which is located on the Lower Brule Sioux Tribe (LBST) Reservation in South Dakota. The Big Bend is the largest remaining meander of the Missouri river in central South Dakota and over the years the erosion of the meander has increased. Working with the USGS and LBST, Oglala Lakota College is helping monitor the erosion at selected sites. Using 5mm resolution Terrestrial Light Detection and Ranging (LiDAR) and Real-Time Kinematic GPS (RTK-GPS) some bank erosion volumes can now be accurately calculated to show that the river is encroaching on and threatening of the tribe’s water and land systems. The first phase (Feb. 2011) of the project involved surveying sections of the meander using LiDAR construct a 3D model snapshot to be used as the datum. The project also archived geographic information systems (GIS) basedata for the area. Basedata included 10 meter elevation models, water flow, geology and soil data. The second year of LiDAR data showed that erosion increased in some areas from 8 feet to 30 feet per year. LiDAR data from February 2011 and March 2013 were merged and analyzed for area and volume differences demonstrating readily apparent visual differences. LiDAR data along with soil and geology data can help to better understand soil erosion rates on those sections of the Missouri River. This information can assist the tribe in evaluating the effectiveness of the current mitigation measures they are using to control erosion. In addition, working with the USGS on this project demonstrated other strategies and mitigation measures that can be employed to delay, or even stop the erosion in the future. This project was supported by NSF TCUP Phase III (Tinant and LaGarry) and NSF EPSCoR (LaGarry).