MAZ

Dear feflow user,

I need some information regarding Discret Feature parameter assignement. My apologies, if questions are basic, but I am a beginner with felfow 6.1.

I would like to modelise a drain which connect two part of a same unconfined aquifer. the upstream portion of the drain collects groundwater. Then the water flows in a closed conduit, and finally water is returned to the aquifer.

My mesh already includes a line which represents the drain. According with user manuel, I should apply Manning-Strickler flow law as 1d feature element. Once I do this, several parameters appear:
1-Cross-sect. area
2- Roughness coefficient
3-Specific storage (compressibility)
4-source/sink
5- In-transfer rate
6-Out-transfer rate

For 1 and 2, I have any problem to assign the correct value. But for the rest I'm not sure. I need help about how to assign properly the parameters:

Does the parameter 3 is relevant in the case of Manning-Strickler flow law? Usually the specific storage is related with confined aquifer, isn't it ? Is it indispensable to set this parameter in my case ?

As I understand, the point 4 is useful when water is added (source) or withdrew from the system. In my case, the drain doesn't bring or extract water from system. Is it correct to pass over this parameter, in my case ?

As I understood, In and out-transfert parameters are used when groundwater is connected with streamflow like a river. Relevant parameter is the transfer flux, and it's Kc/e  ratio (1/m), where Kc = hydraulic conductance of a clogging layer and e = thickness of clogging layer. As the drain is connected with groundwater, I guess this parameter should be assigned, is it right? However, I have no idea about how calculate transfer flux parameter. Indeed drain doesn't have any clogging layer with a low hydraulic conductance as a river ! I could eventually assigned a high Kc value and consider "e" as drain thickness

Cou you provide me some advice for this issues ?

Thank you in advance