Ongoing Information for HELP-D Users

Current version of HELP-D is HELP 3.95 D, update 1 (version number 3.95.1.7, which is displayed after launching the program in the menu item "Help / About HELP"). If you do not use the current version it is strongly recommended to upgrade to it (more information).

Model HELP 3.95 D

Issue #9: Final water storage of a layer at the end of the simulation period is (far) above total porosity

Reason: This error occurs if the percolation through a liner is larger than the calculated maximum percolation through a layer in the subprofile below the liner (i.e. through a layer with a relatively low saturated hydraulic conductivity). For example, this will happen if you have a liner of three layers (clay - GCL - clay) with the GCL having a lower saturated hydraulic conductivity than the clay and you declare the upper clay layer as barrier soil layer and the GCL and the lower clay layer as vertical percolation layer. Then the final water storage of the GCL will be above total porosity.

Workaround: Check your design and the assignment of layers to layer types. In the example above combine the three layers (clay - GCL - clay) to a single barrier soil layer; see the User's Guide on pp. 32 bottom and 33.

Remarks: This issue is not known to occur in model HELP 3.07. It is caused by the correction of another error in HELP 3.07 (see Berger 2002, p. 197, first error shown in Fig. 5).

Model HELP 3.07

Major issues known to the author are described in the paper:

• Berger, K., 2002: Potential and Limitations of Applying HELP Model for Surface Covers. Practice Periodical of Hazardous, Toxic, and Radioactive Waste Management, Vol. 6, No. 3, July 2002, pp. 192-203