|WEPP Release Notes|
Changes in WEPP 2012.8
WEPP model version 2012.8 was released on October 3, 2012. The following is a list of changes since the 2010.1 release:
WEPP Model Updates:
WEPP Windows Interface Updates:
Comments on changes between WEPP model 2008.907 and 2010.1
WEPP model version 2010.1 was released on January 28, 2010. The following is a list of changes since the 2008.907 release:
1. Fixed problem where watershed runoff may be larger than precipitation – This change was to correct a bug in the water balance when upland lateral subsurface flow was added to channels.
2. Fixed problem where soil water content could exceed soil porosity – This change was to correct a bug under very mild freezing conditions where the top 10cm of the soil could exceed the maximum soil water content.
3. Fixed problem where negative soil moisture outputs reported – This change was to correct a problem in surface temperature when freezing soil under certain half thaw conditions.
4. Added soil thermal conductivity adjustment input – Additional input was added to frost.txt customization file to adjust thermal conductivity of unfrozen soil.
5. Adjusted output formatting – Main model text output file has added decimal places to display very small soil loss values.
6. Plant output formatting – The OFE column in the plant output was missing. The rill and interrill cover values were reversed.
7. Added frozen water soil content to graphics output – This contains frozen soil water amount by layer and also total.
8. Fixed evapotranspiration in graphics output – The total evapotranspiration amount was not always the sum of the soil and plant transpiration amounts.
9. Fixed water balance issues – The updated computed runoff values were not being used in all cases. The runoff values may be adjusted by reduction of runoff volume caused by infiltration during the recession for partial equilibrium hydrographs.
10. Updated Single Storm Hydrograph – Used updated runoff values to compute. Allowed more lines to be output to show a more complete hydrograph.
11. Fixed deep percolation problem caused by thin bottom soil layer - If the bottom soil layer is very thin the deep percolation will be restricted causing the soil profile to hold more water. The code has been adjusted to round the bottom soil layer to a 20cm boundary to get full percolation.
12. Added subsurface runon and snow columns to water balance output.
13. Fixed contouring bug where out-of-date contouring scenarios were applied.
14. Fix for freeze/thaw energy getting out of bounds causing large erosion results.
15. Rainfall intercepted by residue – is separated from soil evaporation output, previous WEPP versions included this in Es.
16. Rainfall on snowpack – the rainfall interception amount is now set to zero if there is any snow depth on the day of rainfall.
17. Contouring Fix – Chezy depth-discharge coefficient was being calculated incorrectly.
18. Sediment Yield in Multiple OFE hillslopes – Fix to calculate sediment based on rill width and not topmost rill width which may cause sediment yield to exceed soil loss.
19. Interface fix for CLIGEN PAR file generation – skew parameter was not being calculated correctly when a new PAR file was created from observed data.
20. Interface Change Cover Calibration Tool – In the initial conditions record the rill and interrill cover parameters are filled in with the target cover %.
21. Interface Fix Irrigation – More days can be handled in the fixed date irrigation schedules.Comments on changes between WEPP model 2006.5 and 2008.907
WEPP model version 2008.907 was released on October 3, 2008. The following is a list of changes since the 2006.5 release:
Modifications of Winter Hydrology Subroutines in WEPP
A detailed description of the winter hydrology changes is available here - winter hydrology changes as a PDF file. A short description follows and is also available as a PDF file here - winter hydrology changes (short).
Other changes include the following:
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 , 2004.6 and 2004.700
, 2004.6 and 2004.700
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:
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://topsoil.nserl.purdue.edu/nserlweb/weppmain/cligen/