
                      Sagehen Sample Problem for GSFLOW
                                 January 2012
 
A sample problem with GSFLOW data sets is provided in this subdirectory
to verify that GSFLOW is correctly installed and running on the system.
The sample problem also may be looked at as an example of how to use the 
program. The sample GSFLOW model is for the Sagehen Creek Watershed, 
and is described in the GSFLOW documentation (Markstrom and others,
2008).

Several Control and batch files are provided to run the sample problem
in different model modes and for different module, solver, and input-data
set options that are available for a GSFLOW simulation. These example 
files are provided for use with an executable compiled for your Linux
computer named gsflow that is stored in the GSFLOW_1.1.5/bin subdirectory.
The Control and batch files found in the subdirectory:
GSFLOW_1.1.5/data/sagehen/control_linux and are for the following seven
simulation conditions:

1. GSFLOW mode using the PCG solver and PRMS parameters split into five 
     separate Parameter Files. This condition also provides an example of the 
     use of the subbasin module, and a separate PRMS Parameter File 
     (subbasin.params) is provided to illustrate specification of the relevant 
     parameters: gsflow.sh and gsflow.control
2. GSFLOW mode using the NWT solver and PRMS Parameter Files for condition 1:
     gsflow_NWT.sh and gsflow_NWT.control
3. GSFLOW mode using the PCG solver and climate_hru module using pre-processed
     input climate data, to replace PRMS modules temp_1sta, precip_1sta, 
     ddsolrad, and potet_jh. Four of the Parameter Files used
     for conditions 1 and 2 are unchanged, and the fifth modified to include
     parameters required for use with the climate_hru model and to remove
     parameters not needed for climate_hru: gsflow_climate_hru.sh
     and gsflow_climate_hru.control
4. PRMS-only mode using four Parameter Files, three of which are the same
     as those used in condition 1 and one of which was modified for a PRMS-only
     simulation. The Control File includes only those parameters needed for
     a PRMS-only simulation: gsflow_prms.sh and gsflow_prms.control
5. PRMS-only mode using pre-processed climate data using Parameter Files 
     very similar to condition 3, with the addition of a Parameter File that 
     contains parameters for groundwater cascades (ncascdgw.params): 
     gsflow_prms_climate_hru.sh and prms_climate_hru_control
6. PRMS-only mode demonstrating use of the Map Results module using five Parameter
     Files, four of which are the same as used in condition 4 and an additional
     file that specifies the mapping between the HRU and MODFLOW cell maps (file
     gvr.params): gsflow_prms_map_results.sh and gsflow_prms_map_results.control
7. MODFLOW-only mode using the PCG solver, a minimum-input Control File, and
     a PRMS Parameter File that contains GSFLOW-specific parameters required 
     for MODFLOW-only mode (a Data File is not necessary for a MODFLOW-only
     simulation): gsflow_modflow.sh and gsflow_modflow.control

The data-input files for the problem can be found in the input subdirectory, 
which contains modflow and prms subdirectories. The modflow subdirectory contains 
files related to the MODFLOW and MODFLOW-NWT components of GSFLOW. The prms 
subdirectory contains the Data and Parameter files for each simulation. The 
files ending in 'day' refer to pre-processed climate-data files used with the 
Climate by HRU Distribution module.

To execute a simulation condition, type one of the shell script file names
within the GSFLOW_1.1.5/data/sagehen/control_linux directory from an xterm window.

A gsflow.log file will be written directly to the directory from which a
simulation is initiated. Output files (recharge.monthly, recharge.yearly,
and recharge.total) generated by the Map Results module used in simulation
condition six will be written to this directory. Additional output files will be
written to the output subdirectory and to the modflow and prms subdirectories
under the output subdirectory. The names of the output files are specified in
either the GSFLOW Control File or the MODFLOW name file for each simulation.
Several types of files will be generated, each of which is described in detail
in the GSFLOW documentation. These include:

1. GSFLOW water-budget file (example: gsflow.out)
2. GSFLOW comma-separated-values (CSV) File (example: gsflow.csv)
3. PRMS water-budget file (example: sagehen_prms.out)
4. MODFLOW or MODFLOW-NWT listing file (example: sagehen.mf.list)
5. Calculated heads file for MODFLOW or MODFLOW-NWT (example: 
     head_sagehen.out)
6. MODFLOW GAGE Package output files (example: sagehen_sfrseg13.out)
7. MODFLOW UZF Package output files (example:uz1_sagehen.out)

Several output files are provided with the distribution for comparison
to the results of your simulations. These files are provided in the 
output-test subdirectory and are arranged by the simulation mode and
seven model conditions described above. The results provided were
generated using a executable compiled for a 32-bit Linux-based computer
using gfortran version 4.4.3.

Note that the results calculated using the version 1.1.5 release of the
code differ somewhat from previous results because of the bug in the
Soil Zzone module that was identified and fixed for the 1.1.5 release
(see the file "GSFLOW_v1.1.5_Updates.pdf").


Reference:

Markstrom, S.L., Niswonger, R.G., Regan, R.S., Prudic, D.E., and
Barlow, P.M., 2008, GSFLOW--Coupled Ground-water and Surface-water
FLOW model based on the integration of the Precipitation-Runoff
Modeling System (PRMS) and the Modular Ground-Water Flow Model
(MODFLOW-2005): U.S. Geological Survey Techniques and Methods
6-D1, 240 p.
