Download Free Aquifer Parameter Estimator Book in PDF and EPUB Free Download. You can read online Aquifer Parameter Estimator and write the review.

This 53-page report details aquifer parameter estimation in and near Cedar Valley, west of Utah Lake and the Lake Mountains, in Utah County, Utah. The UGS conducted five aquifer tests on the two most important aquifers in the study area-the principal basin-fill aquifer and the fractured-bedrock aquifer. The aquifer tests on bedrock wells are of particular interest because of the importance of the bedrock groundwater resource in the Cedar Pass area, where surface water and groundwater are scarce. The tests reveal valuable information about the interface between the basin-fill and bedrock aquifers, a key path for groundwater discharge from the Cedar Valley groundwater basin. Aquifer test analysis was combined with re-analysis of existing aquifer-test data and specific-capacity data from well logs to determine a range of hydraulic conductivity, transmissivity, and storativity for the aquifers. Anisotropy was identified in both the basin-fill and bedrock aquifers, and the bedrock aquifer was found to be bounded by semi-permeable aquifer boundaries; a wedge of Tertiary volcanic rock and buried faults are the likely barriers to groundwater flow near Cedar Pass.
Numerical models of flow and transport processes are heavily employed in the fields of surface, soil, and groundwater hydrology. They are used to interpret field observations, analyze complex and coupled processes, or to support decision making related to large societal issues such as the water-energy nexus or sustainable water management and food production. Parameter estimation and uncertainty quantification are two key features of modern science-based predictions. When applied to water resources, these tasks must cope with many degrees of freedom and large datasets. Both are challenging and require novel theoretical and computational approaches to handle complex models with large number of unknown parameters.
This study is an effort to investigate two parameter estimation approaches in groundwater modeling, sequential and combined. Most researches imply that simultaneous use of flow and transport observations would be more beneficial in parameter estimation, however some other researchers rise questions about this approach. They believe due to the differing geological properties of aquifers and consequently differing mathematical basis of groundwater flow compared to transport simultaneous use of different observations might not be useful in every cases. Despite the fact that parameter estimation or inverse modeling is not a new method in groundwater modeling, most modelers tend to use forward modeling to estimate parameters. In this research a synthetic heterogeneous K-field is created using SGeMS Sequential Gaussian Simulation. This K-field, derived zones of porosity and defined boundary conditions make our simulated confined aquifer. The model synthetic observations obtained from forward models MODFLOW and MODPATH, are used in the process of parameter estimation using PEST++. In order to have a better look at the model and find its weak points, different scenarios have been defined. Applying the principle of parsimony, difficulties have been added gradually in each scenario for the model. The sequential approach performs two calibrations: a flow calibration using head observations followed by the transport calibration using travel time observations. Both sets of observations are applied simultaneously in a single calibration run in the combined approach. Although, comparing estimated parameters with the initial synthetic reality values shows the better modeled results for both hydraulic conductivity and porosity while we apply combined approach. However time-cost along with difficulties to find a best weighs in combined approach imply that these differences are not significant.
In recognition of the trend toward using numerical methdos for analyzing aquifer test data, Aquifer Test Modeling delineates the application of numerical Laplace inversion analytical equations and numerical models and demonstrates the use of public domain software. Written by a leading expert with over fifty years of experience, this highly practical text provides a thorough grounding in the terms and methods employed in aquifer test modeling, while also establishing a protocol for organizing and simplifying conceptual model definition and data analysis. Using graphs, tables, and sample datasets to enhance understanding, the author delineates the five major steps involved in the aquifer test modeling process. He discusses the importance of the conceptual model definition as a framework for organizing, simplifying, and idealizing information. The chapters cover the selection of appropriate aquifer test mathematical model equations compatible with previously defined conceptual models and highlight the importance of reviewing the mathematical assumption and the adjustment of data for any departures. They also explain format selection, technique selection, well function or drawdown calculation, and calibration. The book provides five sample data sets to assist the reader in becoming familiar with WTAQ and MODFLOW aquifer test modeling input and output data file contents with confined nonleaky and unconfined aquifer conditions. It includes conceptual models consisting of abbreviated descriptions of aquifer test facilities, aquifer test data, and aquifer parameter values together with selected sample file sets. These are just a few of the features that make the book a valuable tool for estimating the supply and contamination characteristics of aquifers.