A pipe is to be installed between points $A$ to $D.$ The ground level has been recorded and the required level for the underside of the pipe at point A has been calculated. The pipe must fall at a stated gradient $($the ratio of change in vertical height with horizontal distance, $V$:$H$ is given in the table below$),$ with the pipe reducing in level from A to D$.$ A traveller $($height provided in the table$)$ is to be used in conjunction with sight rails to ensure the excavation reaches the correct depth and the pipe is installed at the correct fall. The sight rails must be more than $500mm$ above the ground but less than $1\mathrm{.}7m$ above the ground surface.

$\backslash$table$[[$Point$,\backslash$table$[[$Chainage$],[(m)$