USE OF DRONES (UAVS) TO CHARACTERIZE LARGE WOODY DEBRIS ON THE WHITEWATER RIVER, INDIANA

Large woody debris (LWD) is critical to the health and function of stream systems and integral to stream restoration design. LWD, consisting of wood >10 cm in diameter and >1 m in length, influences habitat structure, flow patterns, sediment deposition, and pool formation. Although much work has been done on the role of LWD in streams in the western U.S., few studies have been conducted in the Midwest and the Ohio River Valley, in part due to the limited supply of LWD. The Whitewater River in southeastern Indiana and southwestern Ohio, however, has a wide riparian corridor and few dams or bank stabilization measures, allowing for the recruitment and transport of LWD. Collecting data on these logjams has, in the past, been quite labor intensive. It is typically difficult to get to large log jams on the river, often entailing multi-day trips to collect quantitative data on the wood (e.g. size, species, measure of decay, etc.) and stream morphology. The use of unmanned aerial vehicles (UAVs), or drones, to survey LWD could greatly reduce the amount of time it takes to complete these surveys. This study aimed to test the viability of using Phantom 4 drones and Pix4D software to generate high-resolution 3- dimensional images (i.e. point clouds) of large log jams to quantify the lateral dimensions of the jam itself and key members (large logs that are structural to the jam). Log jams were initially surveyed and inventoried via canoe float on the Whitewater River from May 30, 2021 to June 01, 2021. Log jams were categorized based on their position (meander, bar apex and bar top jams) and the number of key members contained. We returned to the site of a few of the large log jams in August of 2022 and 2023 to assess the capability of using the Phantom 4 drones to more easily characterize LWD. As efforts increase to improve water quality in the Ohio River Valley, it will be important to integrate LWD in stream restoration design.