MODEL NAME AND VERSION: VFSMOD-W Vegetative Filter Strips Design and 
Modeling System, v5.x.x, Nov. 2008

****************      NEW IN VFSMOD v5.x      ******************
* - code restructured to include pollutant trapping component  * 
* - addition of the pesticide reduction of Sabbagh et al (2009)*
* - design now includes filter design for pesticide reduction  *
* - error checking if input files are missing                  *
****************      NEW IN VFSMOD v4.x      ******************
* - automatic inverse calibration engine                       *
* - global sensitivity and uncertainty analysis modules        *
* - updated versions of the vfsm/uh programs                   *
* - updated program built-in help file (calibration component) *
****************************************************************

DESCRIPTION: VFSMOD-W is a complete design-oriented computer modeling 
system (VFSMOD-W). The  MS-Windows32 graphical user interface (GUI) 
integrates the numerical model  VFSMOD, a utility to generate source 
(upslope) disturbed area inputs for the  model based on readily 
available NRCS site characteristics (UH), and vegetative filter strip 
design, uncertainty and sensitivity analyses menu-driven components.
    VFSMOD, the core of the modeling system, is a computer simulation 
model created  to study hydrology, sediment transport and pesticide
trapping through vegetative filter strips (VFS).  The model comprises
the following: a) a finite element solution is done for the  overland
flow equations for the strip; b) infiltration within the strip is
computed using the Green-Ampt method for unsteady rainfall; c) sediment
deposition and filtration is modeled using an implementation of the 
Univ. of Kentucky grass filtration model; and d) new contaminant 
transport component (first implemented pesticide reduction of Sabbagh et
al., 2009). This model formulation effectively handles  complex sets of
inputs similar to those found in natural events. The  improvements of
this combined model over previous models are the inclusion of:  a) 
state of the art description of flow through the filter; b) changes in
flow  derived from sediment deposition; c) physically based time 
dependent soil water  infiltration; d) handling of complex storm 
pattern and intensity; and e) varying  surface conditions (slope and
vegetation) along the filter. The model is targeted at studying VFS
performance on an event by event basis. VFSMOD, when  combined with the
upslope source area input preparation utility (UH), becomes a  powerful
and objective VFS design tool. Although the model was originally 
developed as research tool, VFSMOD-W can now be used by planners and
regulators  to design optimal filter strips for specific scenarios, and
to determine  relative effectiveness of existing VFS.
    The design objective implemented in VFSMOD-W is to find optimal 
constructive  characteristics (length, slope, vegetation) of a VFS to 
reduce the outflow of  sediment from a given disturbed area (soil, 
crop, area, management practices,  design storm with desired return 
period) to  achieve a certain reduction in % sediment (i.e. that for 
TMDLs). In the  MS-Windows VFSMOD-W modelling system, versions 2.x and 
up, the design task is  automated. The projects for each combination of 
design inputs are automatically  created within the program GUI after 
the user selects a range on the desired  parameters. This new version 
also automatically produces combined analysis  output tables. 
Additionally, the program provides two powerful tools. Once the  
optimal design parameters are selected an uncertainty analysis can be 
conducted  using the graphical tools provided. The objective of this 
analysis is to  identify the level of confidence that the adopted 
design has against the  uncertainties present when selecting the model 
inputs. Finally a sensitivity  analysis procedure is included in the 
GUI to identify the parameters to which  the model is more sensitive 
for a given scenario, thus allowing the user to  economize effort by 
focusing on better identifying just the sensitive  parameters. New in
v4 is an automatic inverse calibration engine, global sensitivity and
uncertainty analysis modules, updated versions of the vfsm/uh programs,
and updated built-in program help file (for the calibration component).
    Documentation for the model is available in several forms (web, 
printable PDF  and on-line program help). This version of the model 
uses inputs that are easily  obtainable from tables and other sources 
contained in the manual.

DESCRIPTION OF NEW FEATURES (v5.X.X)
Major release, version 5.x.x of vfsmod-w with the addition of the pesticide
reduction components of Sabbagh et al (2009). This includes:
- Restructured VFSM code and GUI to add water quality components while 
ensuring backwards compatibility. New IWQ flag added at the end of IKW file
 inputs. If "1" is present there it will expect a new input file with IWQ 
extension and produce a new output OWQ file. If no flag is present or a 
character other that "1" is there it will execute with no water quality 
component. The new program files WQSUB.f handles the processing of the water
quality component when the component is selected. In addition, changes were
made to VFSMOD.f, INPUTS.f, FINPUTS.f and OUTMASS.f.
- Output reader now views the .OWQ
- The "Design" feature of the program also considers pesticide trapping if
the orifinal VFSM project has the IWQ=1. The .CSV output file then contains
a new column (PDR=pollutant delivery ratio).
- Error checking on input files. It will print error and exit gracefully
if any of the project files are missing

DISTRIBUTION: via WWW
USA: http://carpena.ifas.ufl.edu/vfsmod

CONTACT INFORMATION:
R.Munoz-Carpena (carpena@ufl.edu), University of Florida

MODEL INPUTS:
- Vegetative Filter Strip length and slope
- Vegetation characteristics including surface
- Vegetation characteristics including surface roughness, average 
height roughness, average height
- Green-Ampt infiltration parameters for the filter
- Design storm or event hyetograph for the area
- Source (disturbed) upslope area characteristics (dimensions, slope, 
crop practices and NRCS runoff and erosion parameters)
- Pesticide characteristics (when options is selected)

MODEL OUTPUTS:
- Detailed outputs on transport and deposition of sediment within the 
filters
- Detailed outputs on runoff depth and velocity within the filters
- Summary outputs showing sediment in and out along with infiltration 
within the filters (this is used for the design guide)
- Filter effectiveness indicators
- Analysis of sensitivity of selected parameters (if desired)
- Uncertainty analysis of modeling inputs (if desired)
- Design response curves to identify optimal filter dimensions or 
vegetation cover to achieve user defined runoff/sediment reduction rate 
(if desired).
- Pesticide trapping in the filter (when option is selected by the user)

RELATED PROJECTS: Hatch USA-CSREES S-1004 Regional Project: 
"Development and Evaluation of TMDL Planning and Assessment Tools and 
Processes"

DISCLAIMER:
VFSmod was originally developed in the Department of Biological and 
Agricultural Engineering by Dr. Rafael Munoz-Carpena under the 
direction of Dr. John E. Parsons at North Carolina State University.
The model and associated documentation is supplied as-is with no warranty
- explicit or implied. The model is provided to as an educational, 
research and planning tool. This version is the fourth moving the model
from a research tool to one available for general users. As with any model,
the results are totally dependent on the user's ability to wisely select
input parameters that represent the "field" and to interpret the results.
We will make every effort to provide assistance and encouragement as our
other commitments allow. We do ask that you reference our work if you 
find it helpful in your pursuits and also that file bugs or suggestions
to help us improve the program (use form on-line).

Bugs - v5.x.x
None reported yet

Bugs - v4.x.x
None reported yet

Bugs - V2.2.2
1. In the sensitivity analysis section.  If one runs any of the parameters
singly and then repeats the same run with Dp selected, they may get different
results for the Ss sensitivity simulations. The input data for Dp was not
being reset to the original values correctly for the next simulation. This
only affects sensitivity simulations with Ss. If Ss sensitivity is run
alone without selecting Dp, then the results are based on the values of
Dp in the base input datasets selected. This has been fixed in version 2.2.3.

Bug Fixes in the Fortran source code for vfsm.exe (v2.2.1)
- Fixed infiltration solution issue when initial F is 0. It was caused 
by the Newton-Raphson solution algorithm used in the Mein and Larson 
time implicit solution to the Green-Ampt equation. The solution will 
not take as a seed total infiltration F= 0.
- Added work-around for problem found when compiling vfsm with the unix 
g77 (gcc v3.1) fortran compiler. There is a bug in the compiler by 
which local variables are not treated properly. This gave different 
(incorrect) results for the cumulative flows calculated in kwwrite.f 
(written in .ohy file) between code compiled with g77 and other 
compilers (including those in PC). The cumulative values are now 
declared in a common block to force them to be static.

NEW FEATURES IN RELEASE V2.2.XX
I) New, more intuitive, menu labels and lay-out
II) Expanded and improved sensitivity and uncertainty analyses 
procedures. Individual filter areas or combines source-filter areas can 
be now analyzed individually. Multi-dimensional analysis is also 
available as well as print-out of graphical results. Ranges of user 
selected parameters are now automatically checked against physically 
admissible values.
III) VFSMOD and UH have been further refined to improve integration 
with the GUI environment and graphical inputs.
IV) Improved handling of special cases (small runoff, impermeable 
surfaces, saturated soils, etc).

NEW FEATURES IN RELEASE V2.00.XX
I) Model now packed together with MS-Windows GUI for Design and 
Modeling.
II) The new integrated package now includes design, sensitivity and 
uncertainty analysis under the program GUI.
III) Enhaced web and PDF documentations, including new a manual Part to 
discuss the MS-Windows package
IV) Extensive program help built into the MS-Windows (GUI)

NEW FEATURES IN RELEASE V1.06:
I) Fixed problem when incoming sediment was 100% fine. This was caused 
by a line out of sequence in sediment filtration subroutine (step3.f). 
Fixed.
II) changed affiliation of one of the authors.

NEW FEATURES IN RELEASE V1.05:
I) New way of handling a sediment filled strip (grassed.f) . After this 
happens (NFUP=1), all the sediment inflow is routed to the outflow end 
(no deposition) and without stopping the simulation. This way the 
simulation summary (*.osm) now shows realistic trapping efficiencies 
and mass balance (outmass.f).
II) Sediment trapping subroutine (step3.f) re-worked to avoid problems 
with equilibrium slope Se in some cases that led to NaNs.
III) Output format for saturated hydraulic conductivity changed to 
exponential.

NEW FEATURES IN RELEASE V1.04b:
I) Windows GUI to handle UH and VFSMOD programs now available. Both 
fortran codes modified to produce outputs suitable for the GUI.

NEW FEATURES IN RELEASE V1.04:
I) Input preparation program, UH
A program for preparing VFSmod inputs is included as integral part of 
this release. UH uses readily available data to automatically create 
VFSmod the following input files: a) rainfall hyetograph; b) runoff 
hydrograph from source area; and c) erosion loss from source area and 
sediment concentration in runoff. The utility is based on the following 
methods:
- Generates rainfall hyetographs using SCS method
- Generates runoff hydrographs using SCS curve number method and Unit 
hydrograph method
- Erosion estimates done using a version of the modified Universal Soil 
Loss Equation for storm events
- Modifies the Rainfall erosivity factor ± three options
II) Project files added
VFSmod (and UH) now handle project files. This enables the user to use 
any naming convention and directory structure for inputs and outputs.
III) Improved model outputs
New output files give more details on the simulations and a new output 
summary file summarizes filter performance (*.osp)
IV) Updated and expanded documentation.
The manual has been revised and now contains numerous new sections on 
model use, reference tables for inputs to use in the model, and new 
documentation on the UH utility. An on-line version of the manual can 
be found on the web site and a PDF version is included in the 
distribution files.


