Agni: Coupling Model Analysis Tools and High-performance Subsurface Flow and Transport Simulators for Risk and Performance Assessments

Advanced Simulation Capability for Environmental Management (ASCEM) is an emerging state-of-the-art scientific methodological and computational framework for analyzing and predicting subsurface flow and contaminant transport in natural and engineered systems. ASCEM is supported by the U.S. Department of Energy Office of Environmental Management (DOE-EM). The ASCEM framework is designed to provide a modular, object-oriented, and open-source high-performance computational environment that will facilitate assessments of risk and performance for DOE-EM contaminated site cleanup as well as remediation and closure decisions. The ASCEM framework includes three major codes: Akuna, Agni and Amanzi. Amanzi is a parallel high-performance computing subsurface flow and contaminant transport simulator. Akuna is an advanced Graphic User Interface (GUI) that incorporates various data management and model development tools. Agni provides the coupling of Akuna and Amanzi by managing model input and output interactions between the user interface and the simulator. Agni drives Amanzi simulations based on a series of model analysis tools including parameter estimation, geostatistical simulation, uncertainty quantification, risk assessment and decision support. Agni offers efficient parallelization (using system calls, threading or MPI) of the model analysis and simulation tasks in multiprocessor heterogeneous clusters by balancing the utilization of computational resources based on runtime performance. Agni allows coupling not only with Amanzi but also with any other existing flow and transport simulator. Agni is an object-oriented code written in C++ that allows for incorporation of additional model analyses tools.