Model distribution 706/546-3549
BBS 706/546-3402 FTS/250-3402
Purpose:
PIRANHA is a computer-based ecological risk assessment tool. The system includes
a Geographic Information System (GIS) based facility for locating biological resources
potentially at risk from pesticides and industrial chemicals, a toxicological inferencing program
for species-to-species extrapolation of acute toxicity (TIP), models for predicting ambient chemical
exposures in aquatic and agro-ecosystems
(PRZM and
EXAMS),
and bioaccumulation models for aquatic fauna (FGETS).
PIRANHA functions under an interactive platform which incorporates soil, crop, pesticide property, and meteorological data bases.
Model algorithms:
(This discussion is directed to the components of PIRANHA that relate to estimating exposure concentrations from agricultural chemicals.)
Pesticide transport to receiving waters, via runoff and eroded sediment, is calculated using PRZM (Release 1). The creation of input files are automated by the PRZM Input Collator (PIC) which is an interactive platform that allows the user to build scenarios of interest by selecting the crop, pesticide, geographical area, soil, and meteorological period of interest. Geographical-based data is delineated at the Major Land Resource Area (MLRA) scale. Exposure concentrations in aquatic environments are predicted from EXAMSII (Version 2.94).
Input Parameters: Input parameters are those required for PRZM and EXAMS which are found in separate summaries on each of these models. The PRZM input file created from PIC contains default parameters based on the selected geographic region, soil, weather station, pesticide and crop. The user must provide dates of pesticide applications, amount of applied, and depth incorporated, and the climatological period to be simulated. Default values may be changed through menu options in PIC or any standard ASCII editor (run external to PIRANHA). EXAMS input files must be created from scratch or by modifying existing example scenarios.
Output Parameters: Output files are those created from PRZM and EXAMS with the additional feature that an output file from PRZM can be created to provide runoff loads directly into EXAMS.
Critical Assessment:
Strengths of Model:
Ability to rapidly create and execute PRZM simulations, especially for users who are not proficient with DOS or FORTRAN input file formatting. Linkage of models and data bases. Use of default values provides quick, conservative estimates of leaching potential for screening purposes.
Weaknesses of Model:
Must stay within confines of single meteorological station, or at least same geographic region. Does not provide a way to save frequently developed scenarios. Portions are still under development (e.g., AidEXAMS, full data base development for MLRAs).
Internal Diagnostics: Good, on-line help available
Current Version No.: 2.0
source of abstract: ACPA Modeldatabase (04/1998)
Known Bugs: Option to view PRZM output file only allows viewing of EXAMS transfer file. Option to edit soil information in PIC is programmed wrong in that the user must select the option not to edit soil information. Option to edit PRZM titles does not work. New simulations from previously created PRZM files based on "GETINP" do not update the EXAMS loading files.
Input Parameters:
Input parameters are those required for PRZM and EXAMS which are found in separate summaries on each of these models. The PRZM input file created from PIC contains default parameters based on the selected geographic region, soil, weather station, pesticide and crop. The user must provide dates of pesticide applications, amount of applied, and depth incorporated, and the climatological period to be simulated. Default values may be changed through menu options in PIC or any standard ASCII editor (run external to PIRANHA). EXAMS input files must be created from scratch or by modifying existing example scenarios.
Output Flexibility: Little beyond standard PRZM and EXAMS output files(which have their own levels of flexibility).
Graphic Capability: PRZPLOT permits graphical display of annual variations in total pesticide losses, sediment and runoff losses, and precipitation. (The PIRANHA Graphical Display System (PGDS) allows a the user to construct a GIS -intersection of crop growing areas and biological species distribution.)