FEFLOW 6.1_Groundwater recharge input

Hi Users,

The domain consists of 15 polygons. Groundwater recharge data will be inputted into 3D model as daily data for the period of 10 years. How can I input those data to the model? (In FEFLOW 6.1 also showed the way to input GW recharge corresponding to different polygons, but that way  seems to be simple and not able to apply for hourly or daily data of long period).
Thanks in advance,
Lamm

Hi Lamm,

There's an overview of all the different options for assigning time-varying material data in chapter 10.10 in the User Manual (also available from http://feflow.com/manuals.html).

Peter

Thanks for your response.

I have reviewed different options in chapter 10.10. For the method of “Assign Time series to Material Data”: The input map contains one attribute field with all the time stages corresponding to parameter value. However, maximum column could be created in the attribute is only 255 columns. This is impossible to create the number of columns that are more than 255 (for example: 10 years x 365 days = 3650 columns).
I suppose that the method of “Time-series Joining to Maps” could be suitable for my case. However I do not know how to assign different polygons with the corresponding Time series data.  Could you please show me steps to do it?
Lamm

Hi Lamm,
There's a detailed description of the workflows for the different options in the FEFLOW help system: In the tree on the left-hand side, go to Workflows -> Model Setup -> Assignment of Time-Varying Material Properties.

I hope this can help!
Peter

Just noticed that I had not commented on the number of columns yesterday: There's no limit on the number of columns in FEFLOW. Depending on the format you use, there might be limits in the software you are using to create the files. For example, old versions of Excel only support 256 columns (which used to be quite relevant when working on the dbf tables of shape files in Excel). However, newer versions do not have this limitation (but do no longer allow to save dbf...). To overcome these limits, you can also join several tables in FEFLOW if necessary.

I experienced some problems by using the method "Use Map Data: Join Time Series to Maps" (which would be the method of joice in the above case, i suppose).

I had 20 years of groundwater recharge daily values and about 30 different timeseries.

1) I exported the elements (ca 100000) of the first slice and assigned each element one of the 30 timeseries nr in ArcGIS.
2) Then I used the method above, but there were allways some elements with wrong timeseries.

Only by repeating these steps (1+2) for elements with the wrong timeseries, I could solve the problem. In addition this is a very slow process. It didn't help to merge elements in the element shape with the same timeseries.

It is also impossible to export the assigned timeseries (possibly because of the huge amount of data).

My workaround was to analyse and write directly into the ascii-fem file with python.

One reason for this could be a snap distance set to something larger than 0. Then also neighboring elements may get the value set for an element, and the time series ID finally found on the neighboring elements will depend on the input order (order of polygons in the file). So when doing polygon import, you should typically set the snap distance to 0.

Hi Florian,

What are the 30 different time series in 20 years of groundwater recharge? You mean that 30 different timeseries correspond to 30 polygons located in your model domain? Could you explain in more detail?
Did you mention on the polygons in your Domain when inputting the data into your model?
I have reviewed all the methods offered by FEFLOW 6.1 in chapter 10.10 and supposed that these methods are still not clear to input different polygons with corresponding daily data for over a long period (e.g.  from 5 years). Perhaps, this is a limitation of Model!

Lamm

@Lamm
Yes, 30 different timeseries for corresponding 30 polygons.
The Feflow 6.1 Help offers the chapter workflow. one of the features is "Assignment of Time-Varying Material Properties". There you'll find the method offered "Join Time Series to Maps". It is possible to join timeseries (pow data) to polygons (shape). In the end it worked, as well as following budget analysis. There seems to be no limitation (<20years).

@Peter
I'm quite sure that i used a snap distance of 0. (I remember even trying -1). I still hope that Feflow 6.2 offers a method which uses the timeseries editor (like boundary conditions, wells etc.).
I attached two screenshots. The colors correspond to areas of the same groundwater recharge. Colour values are different in both screenshots, they only should cover the same elements. As one can see, there are allways some with wrong values.
You don't have to go into detail, if it's not a known issue. I only wanted to say: Be careful.

Hi Florian,
I need to know the structure of the file.pow (time-series file) which includes TimeSeriesID, Time, and Values. Could you please send it to me?
Lamm

FEFLOW Help System:
Reference -> File Formats -> Database -> *.pow

Hi all,

In 3D groundwater flow model by using Feflow 6.1, I want to ask about the sign for assigning groundwater recharge. Does it minus (-) or plus (+)?

When using the in-/outflow on top/bottom or the source/sink material parameter, inflow (recharge) is positive, outflow (ET for example) is negative. When using a Neumann boundary condition (for example in the case of a vertical cross-sectional model), inflow is negative, outflow is positive.

Hello Peter,
Related to the recharge, I would like to know if i can use the same recharge input file (which has been calculated for a bigger mesh size) to the one with the smaller mesh size?
Thank you

Recharge is in the unit [L/T] (or - equivalent - [L³/(TL²)]), representing a volume of water per time and area. Thus you can basically use the same values, no matter what the element size is.

Dear Peter,

Thanks for your answer. Now I have another problem with the recharge input.
We calculate the recharge from another model but the exported file (in .xls or .cvs) could not import into Feflow.
Could you explain more detail about the structure of the import file for recharge data. I tried to read the description for .pow file in the Help but it still complicated.
Thank you very much.