MODFLOW/SEAWAT 2000WMD Report
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MODFLOW/SEAWAT-2000WMD Report – Version 4 Jorge Restrepo Angela Montoya September 2008 Prepared by the Department of Geosciences, Florida Atlantic University. For the South Florida Water Management District, Water Supply Department. MODFLOW/SEAWAT 2000WMD Report Blank page 2 MODFLOW/SEAWAT 2000WMD Report Acknowledgements Administrative Support: Jeff Giddings, South Florida Water Management District. Reviewers: Special recognition for Laura Kuebler. Reviewers: David Garces, Jeff Giddings and Hope Radin. 3 MODFLOW/SEAWAT 2000WMD Report Blank page 4 MODFLOW/SEAWAT 2000WMD Report Table of Contents Acknowledgements ........................................................................ 3 Table of Contents ............................................................................. 5 List of Tables ...................................................................................... 7 List of Figures ..................................................................................... 9 INTRODUCTION ............................................................................... 11 Introduction Specific to MODFLOW-2000 .................................................. 12 Introduction Specific to MT3DMS ............................................................... 14 Introduction Specific to SEAWAT-2000 ...................................................... 15 Running MODFLOW-2000 and SEAWAT-2000 ............................................ 15 SCOPE OF WORK FOR THE SOURCE MIGRATION FROM MODFLOW-96 TO SEAWAT-2000WMD ........................................... 16 IMPLEMENTATION OF THE SOURCE MIGRATION ........................... 17 Introduction .................................................................................................. 17 General Procedure for Memory Allocation .............................................. 17 INTRODUCTION OF THE MIGRATED PACKAGES TO THE SEAWAT 2000WMD ........................................................................................ 18 Utility Generation (UGEN) Package........................................................... 18 UGEN General Files ...................................................................................................................... 19 SEAWAT package input files using the UGEN ............................................................................. 21 Wetland (WTL) Package ............................................................................. 22 Strongly Implicit Procedure (SIP) Package Enhancements .................... 23 Reinjection Drainflow (RDF) Package ....................................................... 24 5 MODFLOW/SEAWAT 2000WMD Report Multi-Operation Diversion (MDIV) Package ............................................. 24 Trigger Package (TRG) with Multi Well Types ............................................ 26 Multiple Budget (MBUD) Package ............................................................. 28 Interpolation Head Boundary (HBXY) Package ....................................... 28 SEAWAT-2000WMD MODEL VERIFICATION ................................... 29 UTILITY WELL CREATION PACKAGE IN MODFLOW (PRE-WEL/WELT) ......................................................................................................... 30 Model Information ....................................................................................... 30 Permit allocation ......................................................................................... 31 REFERENCES ..................................................................................... 33 Appendix A ..................................................................................... 37 LECsR main name-file and output for the first 100 stress periods for both MODFLOW-96 and SEAWAT(v4) 2000 WMD ................... 37 Appendix B ..................................................................................... 39 LWCFL main name-file and output for 250 stress periods for both SEAWAT(v3) 2000 WMD and SEAWAT(v4) 2000 WMD ................. 39 Appendix C ..................................................................................... 41 USGS case 7 “7_swtv4_ex” main name-file and output for both USGS SEAWAT(v4) and SEAWAT(v4) 2000 WMD .......................... 41 6 MODFLOW/SEAWAT 2000WMD Report List of Tables Table 1 Files used in the pre-processor utility .............................................................................................. 30 7 MODFLOW/SEAWAT 2000WMD Report Blank page 8 MODFLOW/SEAWAT 2000WMD Report List of Figures Figure 1 Example of a portion of the source code is illustrated. .................................................................. 19 Figure 2 CHD, the program showing the interpolation procedure. .............................................................. 21 Figure 3. Time series for the target stage level for a sink cell. ..................................................................... 26 9 MODFLOW/SEAWAT 2000WMD Report Blank page 10 MODFLOW/SEAWAT 2000WMD Report MODIFICATIONS TO MODFLOW/SEAWAT-2000WMD SOURCE CODE INTRODUCTION The purpose of this research is to modify the SEAWAT-2000 (Langevin et al., 2003) software to make it compatible with the customized hydrologic packages used by the South Florida Water Management District (DISTRICT). The updated source code is called herein SEAWAT-2000WMD. The Resource Evaluation and Subregional Modeling Division(RESM) has been using various source codes of MODFLOW and SEAWAT for modeling projects of its own, but so far there is no single source code capable of covering all the required functionality entirely. Thus, the updated code will increase the current capabilities of the modeling software used by the RESM Division by allowing just one program to handle all the tasks that previously were performed by different source codes. RESM applies models using both SEAWAT-2000 and MODFLOW-96 (Harbaugh and McDonald, 1996). A problem arises from the fact that these codes do not include many of the custom packages that RESM applies (e.g., Wetland, Diversion, and GEN packages). The Division would like to combine the hydrologic functionality of the custom packages with density-dependent software in order to properly maintain one source code version. Constant density models have been developed in MODFLOW-96 while the newer codes, such as SEAWAT-2000 (which is built around the more recent MODFLOW-2000 (Harbaugh et al., 2000)), offer both constant and variable density applications with solute transport capabilities. Improving the source code will keep modeling applications current with the needs of the DISTRICT. The Diversion and Wetland packages will be generalized to closely represent the process for the physical system under south Florida conditions (e.g., time- dependent operational rules in the Diversion, solving the diffusion equation using the Wetland package for surface water in any cell presenting flooding conditions). SEAWAT-2000 (Langevin et al., 2003) is a combined version of MODFLOW (Harbaugh et al., 2000) and MT3DMS (Zheng and Wang, 1999; Zheng, 2006) designed to simulate three-dimensional, variable-density ground-water flow and multi-species transport. The Variable-Density Flow (VDF) Process in SEAWAT was based on the constant-density Ground-Water Flow (GWF) Process of MODFLOW. The VDF Process uses the MODFLOW and MT3DMS methodologies to solve the variable-density ground- water flow and the solute transport equations, respectively. The MT3DMS part of SEAWAT is referred to as the Integrated MT3DMS Transport (IMT) Process. 11 MODFLOW/SEAWAT 2000WMD Report Background material is available in the published user guides for SEAWAT, SEAWAT- 2000, MODFLOW-2000, and MT3DMS. The version of SEAWAT used herein (Langevin et al., 2007) is capable of simulating simultaneous solute and heat transport and the effect of fluid viscosity on resistance to ground-water flow. SEAWAT simulates heat transport using the intrinsic capabilities of MT3DMS. With this approach, the effect of temperature is calculated as one of the species being computed by MT3DMS. Other features have also been implemented by the USGS to this version of SEAWAT to improve overall functionality. The new main features are: • An option to update the flow field if fluid densities have changed under a user-specified value. This option may substantially reduce runtimes for some simulations where a new flow solution is not needed for each transport time-step. • Auxiliary variables can now be used with the Time-Variant Constant-Head (CHD) package to designate the reference density associated with the prescribed head. This option allows for more control of boundary heads specified with the CHD package (e.g., sea water). The performance of the updated code program for SEAWAT-2000WMD has been tested in several applications including the Lower East Coast Subregional Model and Lower West Coast Floridan Aquifer Model. Future applications, however, might reveal errors that were not detected in the test simulations. Users are requested to notify FAU of any errors found in the computer program. For convenience, the AMG solver code (Wilson and Naff, 2004) is distributed with SEAWAT-2000. The AMG solver is, however, produced by Institute for Algorithms and Scientific Computing (SCAI), Sankt Augustin, Germany, and thus, though freely distributed, subject to restrictions as defined by SCAI. Introduction Specific to MODFLOW-2000 MODFLOW is a computer program that simulates three-dimensional ground- water flow through a porous medium by using a finite-difference