It helps to prevent sediment from entering the well.
Monitoring well filter sand.
January 29 2013 revision history.
The space between the screened section and borehole is backfilled with filter sand typically fraction silica sand.
Previous versions of the document are.
Selecting the appropriate sand pack can be a challenge.
The most recent version is presented in the top row of the table.
Piezometer 4 2 1 1 2 6 bentonite seal filter pack of sand figure 1.
Wells designed to monitor groundwater to evaluate the changes in the physical chemical and biological properties of water.
Generally a well functions as a monitor or as a pumping or production well.
The annular space above the sand pack is then sealed to prevent surface.
Well pack gravel is used for deep bed in ground wells to form a barrier between the screens and the natural deposit of the land which in turn allows for the well to provide very clean water.
Monitoring well design and installation february 2008 governor.
Mounded bentonite soil mixture well screen well cap riser or stand pipe unslotted soil surface unlined bore hole lined bore hole.
Thomas kwader presents some guidelines for making your choice.
Installation of a filter pack and screen may not be necessary for wells completed in competent bedrock.
If the well is completed with a screen as opposed to an open hole finish in hard rock then the screen usually is surrounded by a sand pack placed by the driller.
Design and installation of monitoring wells design and installation of monitoring wells 101 af r1 effective date.