Filters: Tags: Solute Transport (X) > partyWithName: Office of the Chief Scientist for Water (X)
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Movement of toxic and radioactive substances in aquifer systems occurs in all three phases and is controlled by both hydrologic and chemical forces. Solute movement can be greatly affected not only by physical dispersion, but by other factors such as exchange sorption, chemical kinetics, and ionic distributions. Movement of gases and particulate material in the unsaturated zone are controlled by many additional factors. Knowledge of how these physical and geochemical factors affect prediction of movement of toxic and radioactive wastes is only generally known for ideal systems. This project's objective is to develop field methods and techniques that will yield values for physical and geochemical factors of regional...
Categories: Project;
Tags: Groundwater Flow and Transport,
Radioisotopes,
Solute Transport,
Unsaturated Zone
a) Developing defensible conceptual models of processes influencing the mass transfer of inorganic contaminants between aqueous and solid phases. b) Translating conceptual models into quantitative models that can be used to predict the influence of mass-transfer processes on contaminant fate and transport in field applications. c) Developing approaches to obtain parameters required to describe contaminant mass transfer in quantitative fate and transport models that are, to the maximum extent possible, independent of field observations. d) Testing these approaches in laboratory experimental studies, field experimental studies, and field-scale plume characterization studies.
Biogeochemical processes associated with the microbial community (algae, bacteria, fungi) constitute the interface between solute transport and biotic production in riverine environments. Identifying and estimating the role of biotic processes such as nitrification and denitrification by bacteria, nutrient uptake and production by epilithic algal films and decomposition of particulate and dissolved organic matter, as well as abiotic processes such as absorption, are important for understanding the linkage between terrestrial, riparian, hyporheic and in-channel contributions to the nutrient chemistry of a drainage network. Relative biotic response to solutes in transport between pristine and anthropogenically modified...
The biological and chemical characteristics of aquatic environments depend on a generally complicated balance of physical, chemical, and biological processes. Basic to describing these characteristics is an understanding of transport processes including both advection and mixing. For a given water body, these processes depend heavily on the mass, momentum, and energy transfers at boundaries and the internal response of the system. Many of these transfers and responses are poorly understood. Broad goals of this project are to quantitatively understand the physical processes responsible for the transport of conservative and nonconservative solutes of biological and chemical importance. Through the use of time series...
Categories: Project;
Tags: Solute Transport
Saline hydrologic systems provide a wide range of conditions within which to examine hydrochemically important mineral reaction (alteration or genesis) and to better define reactants and products controlling the chemical composition of many natural waters. The effects of complex reactions, in addition to simple solution and hydrolysis, are reflected in relatively gross chemical change and interaction with fine-grained sediment. The objective of this project is to use saline environments to determine mechanisms and relative importance of mineralogic processes which influence the solute composition of natural waters.
Managing water use in riverine and estuarine systems requires an understanding of the governing supply, circulation, mixing, and flushing processes. Qualitative and quantitative evaluation of the hydrodynamic and transport properties of such water bodies can be computed via mathematical/numerical simulation models. To accurately simulate both the temporal and spatial variations of the flow, which significantly define the transport processes, the simulation model must be capable of accounting for hydraulic and tide-induced fluctuations, water withdrawals, discharges, winds, nonuniform geometric configurations, and other manmade or natural factors. Objectives of this project are to investigate and develop various...
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