A Three Dimensional Hydrodynamic And Transport Model For Lake Environments

Hydrodynamics and Transport for Water Quality Modeling presents a complete overview of current methods used to describe or predict transport in aquatic systems, with special emphasis on water quality modeling. The book features detailed descriptions of each method, supported by sample applications and case studies drawn from the authors' years of experience in the field. Each chapter examines a variety of modeling approaches, from simple to complex. This unique text/reference offers a wealth of information previously unavailable from a single source. The book begins with an overview of basic principles, and an introduction to the measurement and analysis of flow. The following section focuses on rivers and streams, including model complexity and data requirements, methods for estimating mixing, hydrologic routing methods, and unsteady flow modeling. The third section considers lakes and reservoirs, and discusses stratification and temperature modeling, mixing methods, reservoir routing and water balances, and dynamic modeling using one-, two-, and three-dimensional models. The book concludes with a section on estuaries, containing topics such as origins and classification, tides, mixing methods, tidally averaged estuary models, and dynamic modeling. Over 250 figures support the text. This is a valuable guide for students and practicing modelers who do not have extensive backgrounds in fluid dynamics.

This dissertation, "Three-dimensional Modelling of Hydrodynamics and Tidal Flushing in Deep Bay" by Aiguo, Qian, 乾愛國, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Abstract of thesis entitled "Three-Dimensional Modelling of Hydrodynamics and Tidal Flushing in Deep Bay" submitted by QIAN Aiguo for the degree of Master of Philosophy at the University of Hong Kong in December, 2003 Deep Bay is a semi-enclosed shallow bay on the eastern side of the Pearl Estuary, between Shenzhen to the north and the New Territories of Hong Kong to the south. As a result of large-scale development in Shenzhen, Deep Bay has experienced severe water quality deterioration in recent years. Some isolated water quality studies of Deep Bay have been conducted. However, Deep Bay is a unique embayment which exhibits large seasonal salinity variation, and no three-dimensional (3D) modeling of the tidal flushing process has yet been done. The flushing time, a key parameter that governs water quality and biological processes, needs to be quantified using a robust 3D hydrodynamic model. In the present study, a 3D hydrodynamic model of Deep Bay is developed and the 3D salinity and tidal circulation of the bay are systematically discussed. The flushing and dispersion features are studied, and the tidal flats in inner Deep Bay are simulated. The Environmental Fluid Dynamic Code (EFDC) is used to develop the 3D hydrodynamic model of Deep Bay. The topographical configuration, space and time scales, boundaries and boundary conditions are selected based on physical consideration and extensive numerical tests. The model is calibrated and verified against two different field data sets respectively for the dry and wet season. The effect of salinity on velocity field is also examined via a numerical experiment by eliminating any salinity gradient from the measured wet season tidal conditions. The analysis of field measurements and numerical modeling is synthesized, and it is demonstrated that the flows within Deep Bay are characteristic of a well mixed/weakly stratified estuary. The small freshwater flows make insignificant contribution to the salinity structure of the outer Deep Bay area, which is mainly influenced by the inflow introduced from the Pearl Estuary. Based on the validated hydrodynamic model, the tidal flushing is studied using a 3D conservative mass transport model. The flushing times of different parts of Deep Bay are quantified via systematic numerical simulation including: i) real tidal forcing on Deep Bay model and ii) typical M2 tides on a local model with only one tidal open boundary. It is demonstrated that the flushing rate is approximately 0.04 per day (flushing time 25 days) in the inner bay, and increases beyond the middle bay rapidly, to 0.3-0.4 per day at the outer end. The flushing rate is significantly affected in both the dry and wet season by salinity gradients. The dispersion of a continuous pollutant source into Deep Bay is also studied. It is demonstrated that this dispersion conforms to the flushing features within the bay. The source remains in the inner bay area with a high concentration, but is rapidly diluted beyond the Shekou cape cross section of middle Deep Bay. It is therefore demonstrated that severe water quality deterioration in Deep Bay occurs mainly in its inner bay area, and that any "red tide" occurring from time to time in inner Deep Bay will not spread to the bay as a whole. DOI: 10.5353/th_b2979900 Subjects: Hydrodynamics - Computer sim

A derivative of the Encyclopedia of Inland Waters, Biogeochemistry of Inland Waters examines the transformation, flux and cycling of chemical compounds in aquatic and terrestrial ecosystems, combining aspects of biology, ecology, geology, and chemistry. Because the articles are drawn from an encyclopedia, they are easily accessible to interested members of the public, such as conservationists and environmental decision makers. This derivative text describes biogeochemical cycles of organic and inorganic elements and compounds in freshwater ecosystems

As a part of the New York (NY) Bight Feasibility Study, a three-dimensional, time-varying numerical hydrodynamic and transport model of the NY Bight was developed by the U.S. Army Engineer Waterways Experiment Station. For this purpose, the three-dimensional hydrodynamic model CH3D-WES was used, along with a boundary-fitted grid in the horizontal and 5-10 sigma layers in the vertical. The model was calibrated and verified with the field data measured in April and May 1976. As a demonstration of the feasibility of long-term simulation, hydrodynamics and transport were modeled for the period April - October 1976. Model results were furnished as input to a water quality model of the NY Bight, which reproduced successfully the hypoxic event of 1976. This user's reference manual presents a brief description of the theory of the numerical model and its various features. The structure of the computer code, the function of various subroutines, the formats of input data, various data files required, and available output options are described in detail. For illustrative purposes, sample listings of input files are furnished for an example case simulating hydrodynamics and transport in the NY Bight for the month of April 1976. (AN).