HOT SPOT IDENTIFICATION OF LAND USE AND LAND COVER (LULC) CHANGE IN TRI-CITIES, TENNESSEE

The southeastern United States, including Tennessee and the Tri-Cities, has experienced notable Land Use and Land Cover (LULC) changes, with urban expansion leading to increased developed land and population growth in the last two decades. The Tri-Cities (Bristol, Kingsport, and Johnson City) city footprints have increased by 15% in land area since 2000, concurrent with heightened urban development. This study examines hotspots of built-up areas and transitions from vegetation to built-up in Tri-Cities, Tennessee, from 2000 to 2021 due to city boundary expansion. LULC data at a 30m resolution for 2001 and 2021 were downloaded from the National Land Cover Database, and city boundary data were obtained from the Tri-City Development Council. Low, medium, and high-intensity developed land were categorized as built-up areas, while forest, shrub, herbaceous, pasture, and croplands were classified as vegetation land among the sixteen land use types. Nearest Neighbor Index (NNI) analysis was employed for spatial clustering detection, with cluster locations identified using the Nearest Neighbor Hierarchical Clustering method, defining a cluster as 25 points in a one-mile radius. Kernel Density Estimation (KDE) with a quartic kernel and 1-mile bandwidth was used to create a heat map of LULC changes from vegetation to built-up. Johnson City and Kingsport experienced substantial city boundary expansion from 2001 to 2021, while Bristol exhibited limited territorial growth. LULC change from 2001 to 2021 yields NNI values of 0.3182 for built-up areas and 0.2157 for converted built-up areas from vegetation land, indicating spatial clustering across the Tri-Cities region. KDE reveals intense built-up areas throughout the study region, with hotspots at recent annexation boundaries. Johnson City and Bristol demonstrate distinct patterns of vegetation-to-built-up change along these annexation limits, while Kingsport displays comparatively lower hotspot intensity despite significant urban expansion. This LULC conversion increases impervious areas, reducing infiltration rates and contributing to urban flooding. These findings will provide valuable insights for future research on the potential effects of LULC change on flooding in Tri-Cities, Tennessee.