How Well Does the Mechanistic Water Quality Model CE‐QUAL‐W2 Represent Biogeochemical Responses to Climatic and Hydrologic Forcing?

Abstract

Mechanistic water quality models are applied globally for water quality management in rivers and lakes. However, it is unclear how well these models represent the response of lakes to changes in climate and hydrologic conditions. To address this question, we conducted a series of climate and hydrologic sensitivity analyses using a parameterized water quality model, CE‐QUAL‐W2, for the Spokane River and Lake Spokane system. Two experimental tests with climate and flow forcing showed that the model predictions were rather insensitive to climatic‐driven hydrologic changes and a wide range of hydrologic conditions (1st to 99th percentile flows) for two different wastewater treatment plant discharge scenarios. The model realistically represented some aspects of Lake Spokane's observed responses to climatic and hydrologic variability, for example, the water residence time and some water quality trends. However, the model overestimated the reservoir total phosphorus (TPR) concentration by ~37% and the chlorophyll a (Chl a) concentration by ~31% and underestimated the minimum volume‐weighted hypolimnetic dissolved oxygen (DOMIN) concentration by ~26% for a wide range of flows compared to the observed data. In contrast to the model's water quality insensitivity, the modeled temperature was more sensitive to flow than was actually observed in Lake Spokane. This study provides guidance for improving the response of one of the most important mechanistic water quality models to climatic and hydrologic forcing and should help modelers and decision‐makers to develop a rigorous assessment of climate and flow sensitivity to improve the margin of safety when setting total maximum daily load targets.

The influence of hydroclimatic conditions and water quality on evaporation rates of a tropical lake

“…The software used was CE-QUAL-W2 version 3.7, a two-dimensional (2D) hydrodynamic model which considers longitudinal and vertical variations while ignoring lateral variations of hydrodynamic variables (Cole and Wells, 2018). It is suitable for water bodies with great lengths in relation to width and widely applied to study lakes and reservoirs (e.g., Zouabi-Aloui and Gueddari, 2014;Zhang et al, 2018;Ziaie et al, 2019). The model requires data on bathymetry, inflows and outflows, meteorology and water quality (Cole and Wells, 2018).…”

Recalibration of a three-dimensional water quality model with a newly developed autocalibration toolkit (EFDC-ACT v1.0.0): does the model calibrated with a wider hydrological variability become more robust?

“…The model was calibrated with observations from 1 January to 31 December 2006 (one year) and validated with observed data from 1 May to 31 October 2007 (six months) (Zhang et al, 2013). Subsequently, the YRWQM was coupled with a modified submerged aquatic vegetation model (M-SAVM) to study the development effect of submerged macrophytes (Zhang et al, 2015(Zhang et al, , 2016 and epiphyton (Špoljar et al, 2017;Zhang et al, 2018b) on the water quality indicators of the reservoir. An integrated climate-hydrological-water quality (RCM-SWAT-YRWQM) framework was also proposed to elucidate the effects of a changing climate on the trophic state (Zhang et al, 2019).…”

Coupling Hydrological and Hydrodynamic Models for Assessing the Impact of Water Pollution on Lake Evaporation

“…It is a twodimensional (2D) hydrodynamic model that considers the longitudinal and vertical variations, despite the lateral variations. Models with the aforementioned characteristics are ideal for application in water bodies with great length in relation to width [28], such as Lake Santo Anastácio, being widely applied in the study of lakes and reservoirs (e.g., [15,16,33,34]). A two-dimensional model was chosen in this work, as it is possible to analyze the vertical and longitudinal profile of the lake in terms of hydrodynamic characteristics.…”