Testing and application of a two-dimensional hydrothermal/transport model for a long, deep, and narrow lake with moderate Burger number

Abstract

Setup, testing, and application of a 2-dimensional longitudinal-vertical hydrothermal/transport model (the transport submodel of CE-QUAL-W2) was documented for Cayuga Lake, New York, where the Rossby radius is on the order of the lake's width. The model was supported by long-term monitoring of meteorological and hydrologic drivers and calibrated and validated using in-lake temperature measurements made at multiple temporal and spatial scales over 16 years. Measurements included (1) temperature profiles at multiple lake sites for 10 years, (2) near-surface temperatures at one end of the lake for 16 years, (3) high frequency temperature at multiple depths for 2 years, and (4) seasonal measurements of a conservative passive tracer. Seiche activity imparted prominent signatures within these measurements. The model demonstrated excellent temporal stability, maintaining good performance in uninterrupted simulations over a period of 15 years. Performance was improved when modeling was supported by on-lake versus land-based meteorological measurements. The validated model was applied through numeric tracer experiments to evaluate various features of transport of interest to water quality issues for the lake, including (1) residence times of stream inputs within the entire lake and a smaller region defined bathymetrically as a shallow shelf, (2) transport and fate of negatively buoyant streams, and (3) the extent of transport from the hypolimnion to the epilimnion. This hydrothermal/transport model is appropriate to serve as the transport submodel for a forthcoming water quality model for this lake and for other high aspect (length to width) ratio lacustrine systems for which the internal Burger number is order one or greater.

Understanding Lake Residence Time Across Spatial and Temporal Scales: A Modeling Analysis of Lake George, New York USA

“…The mean water age values we simulated for the bays of Lake George fall in the same order of magnitude as the residence time (3.5 days) that was simulated in the shelf area of the main basin of Cayuga Lake, NY, by Gelda et al (2015) and by Rueda et al (2008) who found the transfer of tracers from a bay of Clear Lake, CA, to the main basin required 7 days. Although, water age and residence time are different time scales, Rayson et al (2016) showed similarities between the two time scales in their study of Galveston Bay, Texas, and past studies have assumed water age to be similar to residence time (Duffy et al, 2018).…”

Advancing two‐component partitioning of light scattering in C ayuga L ake, N ew Y ork

“…It has the second largest surface area (172 km 2 ) and volume (9.4 × 10 9 m 3 ) of this group of lakes, with mean and maximum depths of 55 m and 133 m, respectively (Schaffner and Oglesby ). This alkaline hardwater, mesotrophic lake (Effler et al ) has an average residence time of 5.5 yr (Gelda et al ). Nearly 40% of the total tributary inflow from three of the largest streams enters the southern end of the lake.…”

Effects of dimensionality on the performance of hydrodynamic models

“…Alternatively, the models resolve the vertical and one horizontal (longitudinal) dimension -2DV, suitable for elongated deep-water bodies where vertical thermal stratification plays a major role, e.g. CE-QUAL-W2 (Gelda et al, 2015;Kobler et al, 2018;Mi et al, 2020). Finally, three-dimensional (3D) models provide highly detailed spatial 45 data, but require larger computational effort in terms of time and storage.…”