This dataset includes measurements of sediment properties (total organic carbon, total nitrogen, and iron-bound organic carbon) in surficial sediment and sedimenting material from two reservoirs: Falling Creek and Beaverdam Reservoirs, both located in Vinton, VA, USA. To measure surficial sediment properties, sediment cores were collected at the deepest site in each reservoir using a gravity corer, and the top 1 cm was frozen then lyophilized. Sediment cores were collected approximately once per month in both reservoirs throughout the stratified period (May–November) in 2019 and 2021, though sampling frequency and duration varied by reservoir and year. Sedimenting material was sampled using sediment traps suspended approximately 1 m above the sediment in both reservoirs. Iron-bound organic carbon was measured using the citrate-bicarbonate-dithionite method, and we used a CN analyzer (Elementar VarioMax, Ronkonkoma, NY, USA) to determine the amount of OC per unit mass of sediment.