Evaluation of Hydraulic Conductivity Estimates from Various Approaches with Groundwater Flow Models     

Dongwei Sun  Ning Luo  Aaron Vandenhoff  Wesley McCall  Zhanfeng Zhao  Chenxi Wang  David L. Rudolph  Walter A. Illman 《Ground water》2024,62(3):384-404

Significant efforts have been expended for improved characterization of hydraulic conductivity (K) and specific storage (S_s) to better understand groundwater flow and contaminant transport processes. Conventional methods including grain size analyses (GSA), permeameter, slug, and pumping tests have been utilized extensively, while Direct Push-based Hydraulic Profiling Tool (HPT) surveys have been developed to obtain high-resolution K estimates. Moreover, inverse modeling approaches based on geology-based zonations, and highly parameterized Hydraulic Tomography (HT) have also been advanced to map spatial variations of K and S_s between and beyond boreholes. While different methods are available, it is unclear which one yields K estimates that are most useful for high resolution predictions of groundwater flow. Therefore, the main objective of this study is to evaluate various K estimates at a highly heterogeneous field site obtained with three categories of characterization techniques including: (1) conventional methods (GSA, permeameter, and slug tests); (2) HPT surveys; and (3) inverse modeling based on geology-based zonations and highly parameterized approaches. The performance of each approach is first qualitatively analyzed by comparing K estimates to site geology. Then, steady-state and transient groundwater flow models are employed to quantitatively assess various K estimates by simulating pumping tests not used for parameter estimation. Results reveal that inverse modeling approaches yield the best drawdown predictions under both steady and transient conditions. In contrast, conventional methods and HPT surveys yield biased predictions. Based on our research, it appears that inverse modeling and data fusion are necessary steps in predicting accurate groundwater flow behavior.  相似文献   

MATLAB Algorithm Availability Simulation Tool     

Shau-Shiun Jan  Wyant Chan  Todd Walter 《GPS Solutions》2009,13(4):327-332

This paper describes a set of MATLAB functions currently being developed for Space Based Augmentation System (SBAS) availability analysis. This toolset includes simulation algorithms that are constantly being developed and updated by various working groups. This set of functions is intended for use as a fast, accurate, and highly customizable experimental test bed for algorithm development. A user-friendly interface has also been developed for the tool. It is open source and can be downloaded from the Stanford GPS Research Laboratory web site (). Therefore, it provides a common ground for different working groups to compare their results. This paper demonstrates the utility of this toolset by analyzing the SBAS service volume models for the Conterminous United States. The paper describes the functionality provided within the software, and shows an example set of contour plots which are the means for investigating how different algorithms and parameters impact availability.  相似文献   

Urban sprawl and its impact on sustainable urban development: a combination of remote sensing and social media data     

Zhenfeng Shao  Neema S.Sumari  Aleksei Portnov  Fanan Ujoh  Walter Musakwa  Paulo J.Mandela 《地球空间信息科学学报》2021,24(2):241-255

Urbanization is one of the most impactful human activities across the world today affecting the quality of urban life and its sustainable development. Urbanizat...  相似文献