pack material
Graded gravel and sand aggregates placed around a well screen or subsurface drain to prevent the infiltration of fine materials. See [[gravel filter]].
Authorization Path: 2.4.5.2.20.15
Graded gravel and sand aggregates placed around a well screen or subsurface drain to prevent the infiltration of fine materials. See [[gravel filter]].
Authorization Path: 2.4.5.2.20.15