Aerial Cadastral and Flood Assessment for Disaster Risk Management in Appalachia

As natural disasters have continued to become more prevalent in recent years, the need for effective disaster management efforts has become even more critical. Flooding is an extremely common natural disaster which can cause significant damage to homes and other property. Using low-cost drones, 3D cadastre models can be created and combined with flood models to quantify individual building risk before, during, and after flood events. As severe flooding devastated areas nearby to Virginia Tech, the need for accurate flood risk quantification became evident. In this work, we focused on the Appalachian area of the United States for flood modeling. The unique terrain of this area coupled with increasing major weather events has lead to devastating flooding in the area. In particular, we focused on an area in Southwest Virginia, Hurley, due to a devastating flood event in 2021 as well as its proximity to Virginia Tech. Digital Elevation Models from before the flood and available weather data are used to perform simulations of the flood event using HEC-RAS software. These were validated with measured water height values and found to be very accurate, with errors as low as 2 percent. After this, simulations are performed using the Digital Elevation Models created from drone imagery collected after the flood, and we found that a similar rainfall event on the new terrain would cause even worse flooding, with water depths between 29% and 105% higher. Simulations like these could be used to guide recovery efforts as well as aid response efforts for any future events. After this, a major flood event in 2022 shifted our focus to an area in Eastern Kentucky. The terrain in this area has been affected by significant surface coal mining, which became a focus due to the limited amount of research into the impacts of surface coal mining on flooding. Through the digitization of historical topographic maps, pre-mining terrain and land cover is compared to the current landscape with respect to runoff and flood potential. Additionally, multiple mine reclamation methods, including the regrowth of forest, grassland, or shrubland, were looked at to reduce the risk of major flooding in the future after mining has been completed. SWAT simulations showed a significant increase, as large as high as 55.8 percent, in surface runoff from the coal mining in the area. HEC-RAS simulations showed localized increases in flooding resulting from mine lands, with some areas seeing an increase of over 2 feet of water depth. Mine reclamation methods show the potential to reduce the amount of surface runoff, by as much 1 foot of water depth, although these ideal scenarios still do not reach pre-mined levels. While the impact which surface mining has had on the environment can not be fully reversed, significant improvements can be made to prevent future flooding in these areas. After these flood case studies, the water depth modeling is combined with high-resolution cadastre data to produce accurate flood risk assessments for the community and property level.