HSSM simulates contamination associated with these fuels by using three simplified modules that represent the vadose zone, the fuel lens within the capillary fringe, and the aquifer. Each module was developed from a semi-analytical solution of the governing equations. The simplified solutions reduce the extensive computational burden of a fully numeric approach. Lack of availability of field data often limits usage of complex models, and HSSM attempts to include the important phenomena at a reasonable data and computational cost.
The three modules of HSSM are linked in a windows interface that allows for interactive input of data, running of the models, and automated graphing of the model output. A two volume user's guide provides specific instruction for running the model, guidance on selecting input parameter values and interpreting the model output, in addition to the theoretical background of the model. Example applications to field data problems are available from Internet links given on the HSSM distribution page.
The model conceptualizes the release as consisting of
1) vertical transport from near the surface of the capillary fring,
2) radial spreading of an LNAPL lens through the capillary fring and dissolution of
LNAPL constituents into a water table aquifer, and
3) transport in the flowing ground water to a potential exposure lication.
Each component of the conceptual model is treated as a distinct process by separate
models. This report describes the modules for the vados zone, lateral spreading at the
water table and dissolution of constituents into the aquifer, and aquifer transport of
the dissolved constituents to receptor points. Spreading of the hydrocarbon lens and
dissolution of hydrocarbon constituents are transient phenomena, and the aquifer
transport model must be capable of adressing a time-variable source term. This is
incorporated through application of Duhamel's principle to a gaussian-source plume
model. The resulting screening model is computationally efficient and has only
moderate parameterization requirements. Both DOS and Windows interfaces are
provided to create input dada sets, run the model, and graph the results. These
interfaces simplify the procedures for running the model so that the model user may
focus on analysis of his/her problem of interest. To that end, guidance is given for
selecting parameter values and several utility programs are provided to calculate
certain parameters. Typical example problems, which begin with a general problem
statement, show exactly how each parameter of the model should be chosen.
The HSSM model system and its documentation are available for microcomputer (DOS, Windows) systems.
Sorce of abstarct:HSSM homepage at EPA-CEAM (10/99).
Download Installation Instructions for all CSMoS Software (9,683 bytes)
Download HSSM for Windows Installation Disk (1,181,002 bytes) Version 1.20a
Download HSSM for DOS Installation Disk (831,398 bytes) Version 1.10 - Apr '94
Example applications of HSSM to field data
Download HSSM Volume 1: Users Guide (1,205,858 bytes)
Download HSSM Volume 2: Theoretical Background and Source Codes (1,611,238 bytes)
Download HSSM Volume 2: Parameter Variation Data Sets (44,579 bytes)
Download HSSM Readme File (30,974 bytes)
Note: The above documentation files are in Adobe Acrobat (PDF) format: The Adobe Acrobat Reader is available Free from Adobe
Example applications of HSSM to field data