Two trial holes should be dug each 1200 x 1200mm square and 750mm in depth, with a

smaller hole 300 x 300mm by 400mm in depth in the centre which is used for the

percolation (T) test (right).

smaller hole 300 x 300mm by 400mm in depth in the centre which is used for the

percolation (T) test (right).

A smaller test hole, 300 x 300mm by

400mm in depth, can also be used to

carry out a P-test which measures

lateral dispersion rather than vertical

dispersion as measured by the T-test.

400mm in depth, can also be used to

carry out a P-test which measures

lateral dispersion rather than vertical

dispersion as measured by the T-test.