transient modelling with recharge monthly data

i'm new to transient modelling, so I will make a dumm question: I have monthly recharges in shapefiles that I want to input into the model, to do transient simulations. However, once in the model, I find no obvious way of doing this. If i go to Time-serties editor and do Import, it asks me for a .pow file. In the FEFLOW videos there is no description of the structure of this .pow file. How do I input my recharge monthly shapefiles into the model and link to time-series? What is the structure of this .pow file? Do I require it to do transient?

Hi Emilia

The .pow files are defined as two columns (time - recharge). I am attaching an example (be careful with the units).
For 2D models, I usually define the recharge though Neumann BC's, and, for 3D models the recharge is only defined on the top layer through material properties (inflow/outflow).

Hugo Ninanya
hninanya@outlook.com

thanks for the answer. At least now I know the structure of a pow file. Thank you!
However I do have a problem. First my recharge is not a unique value for the whole model domain. In fact it is a patch of different values, in accordance with soil characteristics and land cover. So I do have not one value for each time step (which I assume is the first column) but several. In this case, how do I build my pow? And in fact is there no other simpler alternative to input the recharge values? I have my stuff in shapefile.

You can link the data in the shapefile to a user defined element distribution, but only one time step at a time as user data distributions can't be time varying for some reason. So, you could have one element distribution for January, one for Feb etc. Only practical if you have cyclic yearly data.

Then you need to make the in/out flow on top/bottom equation calculate the recharge for each time step with reference to the user data. For example, you could enter a series of IF equations that check model time, and if in certain ranges read the data from the correct elemental array.

For a model longer than 1 year, I'd set up an intermediate POW file with day in column 1 and the month of the year in column 2. Then in the in/out on top/bottom equation refer to the POW data to look up which monthly array to use as an index, and then use IF statements to pick the actual array to be used.

Having said all that, I do areally distributed recharge differently. I have a POW file with daily rain, a user elemental reference distribution for landuse that contains a multiplication factor, and another user elemental reference distribution for soil that contains a second multiplication factor, and multiply the three in the afore mentioned equation.

Attachment shows how to refer to monthly arrays.

i want to add daily recharge data for the model more than 20 years. but shapefile only support 200 somthing timesteps. any other way?

Yes, the dbf-format for storing attribute information of the shapefile has limitations in the number of columns. You could try to use another method to assign time-series for the recharge. Please try to use [b]Use Map Data: Assigning Time Series to Material Data[/b]:
http://www.feflow.info/html/help71/feflow/mainpage.htm#rhtocid=8.2.1.0_6&t=09_Parameters%2FMaterial_Properties%2Ftime_varying_materials.html%23Use_Map_Data%3A_Assigning_Time_Series_to_Material_Data