Packer Test (Lugeon) for rock underwater (below a lake)

[Silty]

Hi All,
I am going to do packer tests to get permeability of rock below a small lake (approximately 5 m of water above the surface of bedrock). The drilling and test will be done from a barge.
When I look at text books, I see below groundwater level a pump out test is better than a pump in test, but couldn't find much about pump out test and how it gives Lugeon.
Any explanation or referral to proper references will be appreciated.
Thanks

 

[GeoEnvGuy]

When you perform packer testing in bedrock you are determining the permeability of each interval tested typically 5, 10, or 20 ft lengths. With this information you can plan your grouting program or estimate inflow at different elevations for underground workings.

Doing a pump out test with a pump in the hole you are determining the overall permeability of the borehole and aquifer. Given that the permeability in bedrock is controlled by small fractures and is not a homogeneous isotropic medium the packer test provides a better characterization of the bedrock permeability.