We calculated the discharge rate of water in cubic meters per second at multiple tributaries flowing into Falling Creek Reservoir, Beaverdam Reservoir, and Carvins Cove Reservoir using four different methods: a handheld flowmeter probe, salt injection, velocity float, or bucket volumetric with cross-sectional discharge calculations. For the flowmeter method, discharge was estimated by measuring the velocity (in meters per second) using a propeller flowmeter (Forestry Supplies, Inc. Model FP 111) or an instantaneous velocity meter (Marsh-Mcbirney Flo-Mate Model 2000656) and depth (in m) at 0.1-0.5 m width intervals, usually 0.1 m, along a cross-section of the stream. The velocity was multiplied by the width and depth to calculate discharge at each transect, which were then summed to calculate total discharge along the stream width, following the methods in Gordon et al. (2004) and detailed further within the standard operating protocol (SOP) included in this data package. For the salt injection method, discharge was calculated by injecting a known mass (in g) determined as a relative proportion of stream width (see SOP included in this data package for more information) of NaCl into the stream and measuring the change in conductivity over time downstream using an EcoSense (EC 300A, serial number JC01635) conductivity meter, following Gordon et al. (2004). Conductivity measurements were taken at 3-second intervals until the conductivity returned to baseline readings (see SOP for more information). When streamflow was not conducive to using flowmeter or salt injection methods, discharge was estimated using a velocity float or bucket volumetric method, following methods outlined in Gordon et al. (2004) and within the SOP included in this data package. For an example illustrating the bucket volumetric method, please see the .xlsx file attached to this data product titled 'CCR_VolumetricFlow_2020_2022_calculations.xlsx'. The bucket volumetric flow method .xlsx file was only used from 2020 - 2022, sample collected after 2022 using this method were calculated using the "ManualDischarge_qaqc_2023_2023.R" script. The "ManualDischarge_qaqc_2023_2023.R" script was only used to calculate and QAQC discharge measurements in 2023.
Data were collected weekly to monthly from February through October 2019 at Falling Creek and Beaverdam Reservoir, approximately monthly at Falling Creek in 2020-2022, approximately monthly at Carvins Cove in 2021-2022, and approximately seasonally in 2023 at Falling Creek and Carvins Cove. All data were collected in local time (either EST or EDT), and if time was not recorded when sampling, the time was set to 12pm.
Discharge from 2023 was calculated using equations in the R script "ManualDischarge_qaqc_2023_2023.R" and "ManualDischarge_inspection_2019_2023.Rmd" was used to validate data and apply additonal flags. Flags for discharge include: flag 3 "Value suspect, conditions not well captured by flowmeter method", Flag 5 "Value suspect, conditions not well captured by velocity float method", and a csv of dates and sites that this flags apply to are recorded in "ManualDischarge_maintenancelog_2019_2023.csv".
See the 'site_descriptions.csv' file for a full description and GPS coordinates of the sites included in this data package.
Additional notes: Multiple whole-ecosystem experiments have been conducted at Falling Creek Reservoir, including intermittent operation of hypolimnetic oxygenation (HOx) and pulsed epilimnetic mixing (EM) engineering systems. We encourage you to contact the lead author of the data package for more information.
References: Gordon, N.D., T.A. McMahon, and B.L. Finlayson. 2004. Stream Hydrology: an Introduction for Ecologists, 2nd edition. John Wiley & Sons, Inc., New York.
