Jiale Wang

Thanks! I have got it :)

Thanks for your reply, Pete!

According to your annalysis, I think the reason is in the second case. Because the big spring's flux (160,000 m3/d) is so large that I have to use a large value of transfer rate.

Now I'm thinking of using fixed drawdown pumping well to represent the big spring. But I don't know how to set fixed drawdown pumping well in FEFLOW.

So could you tell me how to set fixed drawdown pumping well in FEFLOW?

Looking forward to your reply!

Hi! Now I'm modeling a big spring in a karst area. I used transfer boundary to represent the spring. The spring's outflow elevation was used to be reference hydraulic head. The parameter of transfer rate was calibrated accoring to the observed spring outflow.

But when I checked the outflow of spring through Budget analyzer to check the flux at the transfer boundary, the flux value wasn't changed too much even if I changed several orders of magnitude of transfer rate.

So my question is why the flux value at my transfer boundary wasn't changed when I changed the transfer rate severely?

Looking forward to your reply! Thanks!

Sorry I probably didn't express my intention clearly. In my description before, I just simplified the condition. In fact, boundaries of slice1 and slice2 both  are indeed flux boundaries according to hydrogeological analysis. So I would assign flux value on those two slice boundaries according to Darcy's law.

When calculating flux value at slice1 boundary, I use "K" of layer1 which is an aquifer. But when calculating flux value on slice2 boundary, I'm confused how to determine the "K", The "K" of upper aquifer or the "K" of lower aquitard, or an another integrated parameter?

Thanks!

The flux boundary is assigned on slice. In my model I have two layers- the upper is aquifer and the lower is aquitard, and I need to assign flux value on the boundary of slice2 which is between those two layers. So what did you mean by "additional layers"?

If I use transfer boundary, what dose "Reference hydraulic head" mean in my model and how to determine it. So I think the flux boundary is better.

Thanks for your reply! I have got the idea!

Thanks for your reply!

But when I set flux value on the boundary of slice2 which is between an aquifer and aquitard, I have to use Darcy's law (q=KI ) to estimate the flux value. Then which "K" should I use? The "K" of upper aquifer or the "K" of lower aquitard, or an another integrated parameter?

Thanks!

Hi! I'm a new user of FEFLOW. In my model, the northern boundary is impervious. So I didn't prescribe any boundary condition at this border, which means the northern border was set as a "0" flux boundary.
But when I check the flux across the northern boundary using the tool of "Fluid flux analyzer" after running the simulator, the value of fluid flux across the "0" flux boundary is not zero. So I'm very confused why the flux is not zero.
Looking forward to your reply! Thanks!

Hi! I'm a new user of FEFLOW. Now I'm very confused when I set flux boundary condition. I only have the data of hydraulic gradient and approximate hydraulic conductivity of different layers near the boundary. The boundary should be set as a flux boundary. And the flux value on boundary only can be estimated according to Darcy's law.
The first layer is an aquifer and the secend layer is an aquitard. Then when I set the flux boundary condition on the second slice between the aquifer and aquitard, how could I get the flux value according to Darcy's law, using the hydraulic conductivity of the upper aquifer or the lower aquitard?
Looking forward to your reply! Thanks!