Issue with mapping drain coverage to MODFLOW

[RSP21]

Hi All, 

I have created a few drain coverages, when I map these coverages to MODFLOW, one stress period before that defined in the original coverage becomes active as a drain. 

For example, in the screenshot below in the coverage I define the beginning of drainage at timestep 61 (as indicated by a conductance value of 1).

However, when examining sink/sources for cells defined as a drain using that coverage, the timestep prior to the one defined in the coverage becomes active and is given a conductance value ~ half of that given to other stress periods as shown in figure below:

The final  drainage timestep in the coverage is correctly defined as the final drainage timestep once mapped, however it too is given a conductance value ~half of that given in the interim stress periods.

Could someone please advise what is happening here, and whether it is possible to have a consistent conductance value assigned to the timesteps originally defined in the coverage?

[Sean Czarniecki]

Tough to describe here, but I'll try to do it briefly.  You actually have to set it up to have 2 values for the same time.  The first value would be zero and then second will be one.  Then when you want to end having it be one, you make another entry for that same time and make it zero.  It ensures that there is no averaging from one time step to the next.