Use of Elcom and Caedym for Water Quality Simulation in Boulder Basin

Abstract

The growth of the Las Vegas Metropolitan area may eventually lead to increased wastewater discharges into Boulder Basin of Lake Mead (Figure 1). Boulder Basin has experienced several algal blooms over the last few years. As a result, alternate discharge locations and strategies are being investigated. Thus, studying the water quality in Boulder Basin becomes imminent in order to assist various agencies in making decisions on operations within Boulder Basin. Due to its extremely irregular shoreline and large surface area, Lake Mead cannot be simulated adequately by one or two-dimensional models. Therefore, ELCOM (Estuary and Lake COmputer Model), an advanced three-dimensional hydrodynamic model coupled with CAEDYM (Computational Aquatic Ecosystem DYnamics Model) was chosen to simulate threedimensional transport and interactions of flow physics, biology, and chemistry in the reservoir. ELCOM was designed for practical numerical simulation of hydrodynamics and thermodynamics for inland and coastal waters. The code links seamlessly with the CAEDYM model undergoing development at the University of Western Australia Centre for Water Research. The combination of the two codes provides three-dimensional simulation capability for examination of detailed changes in water quality. Figure 2 shows the three-dimensional ELCOM grid used for the Lake Mead simulation. This work involves the setup and application of the models for Boulder Basin. Comparisons between measurements and simulation results show that ELCOM can accurately simulate the temporal and spatial variations of physical (e.g., temperature and conductivity), biological (e.g., chlorophyll-a and total organic carbon), and chemical (e.g., nitrogen and phosphorus) parameters. This study indicates that the hydrodynamic patterns of Boulder Basin are mainly driven by the Colorado River inflow, the Hoover Dam outflow, and meteorological parameters (especially episodes of high wind speed). However, the water quality of Boulder Basin is also affected by the load of nutrients (mainly phosphorus) from the Las Vegas Wash, which carries 3943 WEFTEC®.06

3-D Water Quality Simulations in Mornos Reservoir

“…The mathematical formalism of physical and biochemical processes, and the parameters and coefficients used by ELCOM-CAEDYM, have been described by Karalis, 2007). Relevant references, with respect to CAEDYM, may also be found in Chioni (2005) and in Papadimitrakis and Chioni (2006), whereas interesting applications of these two models can be found in Hannoun et al (2006), Leon et al (2005) and Feaver et al (2002). More specific applications of ELCOM, related to the behavior of internal waves in a stratified lake, can be found in Hodges et al (2000).…”