Recharge zones

[Natasha R G]

Hie everyone

I got these recharge values calculated from my monitoring wells, using the Water Table Fluctuation method. So when it comes to assigning the recharge zones, is it wise to make each of the wells a recharge zone? I realised the problem with doing this is that only 1 cell is assigned a recharge value, so only 8 cells in total get a recharge value. How best can I account for this?

Thank you in advance

Kind regards

Natasha

[Pierre Matran]

Hi Natasha,

How about performing spatial interpolation between your recharge point (wells) over your model grid to get continuous value of recharge ...?

Pierre

--
You received this message because you are subscribed to the Google Groups "MODFLOW Users Group" group.
To unsubscribe from this group and stop receiving emails from it, send an email to modflow+u...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/modflow/CAL_3HiNcPh-8H1j79%3DH3xVWYrDsgffBE_n3m8MRZrv0roj1crw%40mail.gmail.com.

[Natasha R G]

Hie All

Following my previous email, I did the spatial interpolation, and the model failed to converge. However, if i use a single value of recharge on my whole model domain it does converge. What could be possibly going wrong?

Regards

Natasha

To view this discussion on the web visit https://groups.google.com/d/msgid/modflow/CALGJR7uzEjXTa3JdiiTHd0Y1U3-rMbe3rXwB7Zs18A9TbAPVPA%40mail.gmail.com.

[blazer....@gmail.com]

Hi,

Ok, that's sounds weird! But we need more details to help you more:

- Are you using a GUI like ModelMuse, Visual Modflow ... or the python package FloPy to build your model?

- What modflow version do you use ? (MODFLOW-2005 or MODFLOW6)

- What kind of package did you use for the recharge condition (rch or rcha)?
- What kind of interpolation did you perform (krigging, idw, ...)?
- Does your interpolation correspond to your grid (same nrow, ncol or same cell node numbers if you are working on unstructured grid ..)?

Regards,

Pierre

[Richard B. Winston]

Maybe some cells are going dry especially in areas with lower recharge.

To view this discussion on the web visit https://groups.google.com/d/msgid/modflow/CAL_3HiMhhMD8NJfp%3D7k%2BARcVBe9M0yrdyX%2BsqcSUVhX%2BqU%3D5Sg%40mail.gmail.com.

[Natasha R G]

Hie

Thanks for your response.

I am using ModelMuse, MODFLOW2005 and the rch package.

So i basically imported my recharge  as a point.shp, with 8 points (as seen on the excel sheet attached earlier). I then used the nearest point interpolation method in ModelMuse. I am not quite sure how to determine whether my interpolation and grid align. Please advise on how I can do that.

I noticed that, when I apply a single value of recharge to my wetland boundary(polygon.shp), which is basically my whole model domain, my model converges perfectly. Using this technique isn't however so favourable because my recharge is variable throughout my wetland, with the salt pans having the highest recharge rate. 

So, does it mean recharge should always be imported as polygon.shp instead of point.shp?

Kind regards

Natasha

To view this discussion on the web visit https://groups.google.com/d/msgid/modflow/20ae434f-c1c9-4bba-a444-fc812a31654cn%40googlegroups.com.

[Richard B. Winston]

You should color the grid with the recharge to make sure it is being applied the way you want it to be applied.

To view this discussion on the web visit https://groups.google.com/d/msgid/modflow/CAL_3HiO_w9sQd-WfTuSPRP%3Dv0JC1OFok6oeF8LvE2Q11oCb-3w%40mail.gmail.com.

[Natasha R G]

Thank you. 

I ended up establishing polygon.shp of recharge zones, the model seems to run properly after that. Thanks once again!

Regards

Natasha

To view this discussion on the web visit https://groups.google.com/d/msgid/modflow/7d8f0e37-1216-42cd-8cf7-25d3ca0e180a%40mindspring.com.