When water is withdrawn from the sands, hydrostatic pressure in the sands is reduced, causing water to move from the clays and silts.
(water; is withdrawn; from the sands) (hydrostatic pressure in the sands; is reduced; T:When water is withdrawn from the sands)
water hydrostatic pressure in the sands
is withdrawn is reduced
from the sands
T:When water is withdrawn from the sands