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Water column chlorophyll a was analyzed from 2014 to 2024 in seven freshwater reservoirs in southwestern Virginia (VA), USA, and one freshwater lake in central New Hampshire (NH), USA. These waterbodies are: Beaverdam Reservoir (Vinton, VA), Carvins Cove Reservoir (Roanoke, VA), Claytor Lake (Pulaski, VA), Falling Creek Reservoir (Vinton, VA), Gatewood Reservoir (Pulaski, VA), Smith Mountain Lake (Bedford, VA), Spring Hollow Reservoir (Salem, VA), and Lake Sunapee (Sunapee, NH). Beaverdam, Carvins Cove, Falling Creek, and Spring Hollow Reservoirs are owned and operated by the Western Virginia Water Authority as primary or secondary drinking water sources for Roanoke, Virginia; Gatewood Reservoir is a drinking water source for the Town of Pulaski, Virginia; and Smith Mountain Lake is jointly treated by the Bedford Regional Water Authority and the Western Virginia Water Authority as a drinking water source for Franklin County, Virginia. Claytor Lake is managed for hydroelectric power generation by the Appalachian Power Company. Lake Sunapee is a glacially-formed lake known for its oligotrophic water quality. The dataset consists of depth profiles of chlorophyll a samples generally measured at the deepest site of each reservoir adjacent to the dam or at the buoy site of Lake Sunapee. The water column samples were collected approximately fortnightly from March-April and weekly from May-October at Falling Creek Reservoir and Beaverdam Reservoir, approximately fortnightly from May-August in most years at Carvins Cove Reservoir, approximately fortnightly from May-August in Gatewood and Spring Hollow Reservoirs from 2014-2016, approximately fortnightly from May-August of 2014 in Smith Mountain Lake, sporadically from May-August of 2014 in Claytor Lake, and sporadically from June-August of 2021-2022 and 2024 in Lake Sunapee. Additional chlorophyll a samples were collected at multiple upstream and inflow sites along tributaries to Beaverdam and Falling Creek Reservoirs in summer 2019. The water samples collected were analyzed for both phaeophytin and chlorophyll a to quantify and correct for degraded phytoplankton within the sample. 

Depth profiles of total and soluble metals were sampled from 2014-2024 in three drinking-water reservoirs: Falling Creek Reservoir (FCR), Beaverdam Reservoir (BVR), and Carvins Cove Reservoir (CCR). FCR and BVR are located in Vinton, Virginia, USA and CCR is located in Roanoke, Virginia, USA. Only Fe and Mn were analyzed from 2014-2019. The full suite of metals (Li, Na, Mg, Al, Si, K, Ca, Fe, Mn, Cu, Sr, Ba) were analyzed from 2020-2024. All reservoirs are owned and operated by the Western Virginia Water Authority and are managed as drinking-water sources for the city of Roanoke, VA. The dataset includes metal samples that were collected along a depth profile taken at the deepest site of each reservoir near the dam. Additional samples were collected at a gauged weir located on the primary inflow tributary, as well as at a secondary tributary to FCR. A 2024 sampling campaign at FCR included outflow spillway surface water sampling. A 2022 sampling campaign at CCR included inflows and a partial depth profile at the deepest site. Sampling frequency in FCR and BVR in 2024 was approximately weekly during the summer and fall (May - October), approximately fortnightly during the spring (March - April), and approximately monthly during the winter (November - March). In 2022, sampling frequency at CCR was approximately fortnightly during summer and fall (May - October). 

Discrete depth profiles of water temperature, dissolved oxygen, oxidation-reduction potential, conductivity, specific conductance, and pH were collected with multiple handheld water quality probes and discrete depth profiles of photosynthetically active radiation (PAR) were collected with a LI-COR underwater light meter from 2013 to 2024 in five drinking water reservoirs in southwestern Virginia, USA. These reservoirs are: Beaverdam Reservoir (Vinton, Virginia), Carvins Cove Reservoir (Roanoke, Virginia), Falling Creek Reservoir (Vinton, Virginia), Gatewood Reservoir (Pulaski, Virginia), and Spring Hollow Reservoir (Salem, Virginia). Beaverdam, Carvins Cove, Falling Creek, and Spring Hollow Reservoirs are owned and operated by the Western Virginia Water Authority as primary or secondary drinking water sources for Roanoke, Virginia, and Gatewood Reservoir is a drinking water source for the Town of Pulaski, Virginia. All discrete depth profiles were collected on approximately 1-meter intervals. The data package consists of two datasets: 1) Secchi depth data; and 2) discrete depth profiles of multiple water quality variables measured by handheld sensors. The Secchi data and discrete depth profiles were measured at the deepest site of each reservoir adjacent to the dam, as well as other in-reservoir sites. Handheld sensor measurements were also collected at a gauged weir on the primary inflow tributary, other inflows, and outflows at Falling Creek Reservoir; inflows and outflows at Beaverdam Reservoir; and inflows at Carvins Cove Reservoir. In 2021, YSI handheld data were also collected from a littoral site in Beaverdam Reservoir. Data were collected approximately fortnightly in the spring months (March - May), weekly in the summer and early autumn (June - September), and monthly in the late autumn and winter (October - February) in Falling Creek and Beaverdam Reservoirs; data coverage in the other three reservoirs varies among years. Note there are some YSI depth profiles and Secchi observations that were measured at night during overnight sampling. All of these observations have the correct time associated with them. There was a major revision of this dataset from its previous version, which included correcting times of observations, including values of negative ORP, and adding observations from an outflow at Falling Creek Reservoir.