Comments on changes between WEPP model versions 2004.7 and 2006.5
WEPP model version 2006.5 was released on May 18, 2006. The following is a list of changes since the 2004.7 release:
Subsurface lateral flow processing was added by Shuhui Dun and Joan Wu at Washington State University. More details about the processing can be found here. The water output file has a new column that indicates the amount of subsurface lateral flow for each day of the simulation. The pass files generated for watershed simulations have a new element name SUBEVENT to indicate any subsurface flow. The main output file for watershed simulations contains a field for the subsurface flow. In watershed simulations all upstream subsurface flow from hillslopes is added into the channel.
The soil file input can now include an optional restricting layer that defines the hydraulic conductivity of a restricting layer and the anisotropy (horizontal vs vertical) of the entire soil profile. A description of the new soil file can be found here. The new soil file has a different version number to indicate if the restricting layer is present. Existing soil files will work with the 2006.5 WEPP model.
WEPP rock correction factor change from Susan Skirvin, ARS Tucson Arizona. A detailed description of the change can be found here.
When 2006 version soil files are used the minimum saturated hydraulic conductivity is set at 0.000000108 mm/hr during the simulation. For other soil versions the minimum saturated hydraulic conductivity is set at 0.07 mm/hr.
Radiation inclinations are computed separately for each OFE in a watershed simulation to more accurately account for snow melt.
Formatting changes in several output files to account for more hillslope or channel identifiers and to fix column alignments.
Comments
on changes between WEPP model versions 2002.7
WEPP model version 2002.7 was publicly released in July 2002. WEPP model version 2004.6 was released on July 6, 2004 with the following changes:
The 2004.6 version includes several bug fixes and improvements, particularly to the model water balance and handling of plant and residue interception water.
Fixes
to watershed version where program would stop execution in the TABLE
function.
An error was identified in WEPP model version 2004.6 in predicting peak runoff rates for some situations, leading to unrealistic runoff and erosion rates. The 2004.700 updated model executable released September 14, 2004 corrects the problem.
Comments on changes between CLIGEN versions 4.2 and 5.2
CLIGEN
version 4.2 was modified to version 4.3 to allow simulation using single climate
station parameter input files, instead of the old "stations" and state
procedure. No changes were made in
v4.3 to computations within CLIGEN. Version
4.3 is used with the new sets of individual station parameter files provided by
the USDA-Forest Service, Moscow, ID. Corrected
and extended input parameter sets for individual U.S. stations have been
provided by the U. S. Forest Service, Moscow, Idaho. (Many derived from Arlin
Nicks' original data.)
CLIGEN
version 4.2 was subsequently recoded to conform to the "Water Erosion
Prediction Project (WEPP) Fortran-77 Coding Convention".
The code structure was radically simplified and the code extensively
commented. Corrections to peak
intensity calculations proposed by Dr. Bofu Yu, were added to the code, to make
peak intensity responsive to differences in latitude as originally intended.
The new code has been verified to give results identical to Dr. Yu's. Logic has also been added to CLIGEN version 5.2 to ensure
that the random numbers upon which Cligen's outputs are based on are of
satisfactory quality.
Because
CLIGEN uses single parameters to derive daily values for the entire month, three
schemes of interpolation/disaggregation were coded to provide more continuous
daily values between the monthly ones. These are:
1.
simple linear interpolation.
2.
Fourier series.
3.
a modified linear interpolation which preserves the mean value of the parameter
for the month.
The
impact of these interpolation schemes on predictions of runoff and soil loss by
WEPP is still under evaluation.
To
facilitate use of CLIGEN by user interfaces, the following command line options
were added: -S state number, -s station number, -i input filename, -o output
filename, -b beginning year, -y years duration, -r random seed, -I0 no
interpolation (default), -I1 linear interpolation, -I2 Fourier interpolation,
-I3 interpolation to preserve the monthly means, -?, -h help.
The
CLIGEN code is continuing to be evaluated and modified as necessary.
More information about CLIGEN 5.2 is available at: http://horizon.nserl.purdue.edu/Cligen/