A Treatise On The Principles And Practice Of Harbour Engineering

32 HARBOUR ENGINEERING able risk, and the first step to be undertaken in any attempt at an ameliora- tion of the conditions was manifestly the creation of a sheltered area, within which barges could move freely and without danger. There were no natural features to lend assistance to such an undertaking, and purely artificial dispositions had to be made. The initial design was prepared by the late Mr Wm. Parkes, and consisted of two breakwaters projecting perpendicularly to the coast-line, with rectangular returns ter- minating centrally in pier heads, 450 feet apart. Subsequently, the plan was modified by the Marine Department, so that the return angles became Fio. 31. —Madras Harbour. Sketch showing extent of damage done by storm of 12th November 1881. obtuse and the entrance width was increased to 550 feet. The arrangement as adopted is shown in fig. 31. The north pier was commenced in 1875 and the south pier two years later. Unfortunately, as the worlc was carried out from the coast-line, the sand accumulated about it to the southward so rapidly as to cause the line of foreshore to keep pace almost with the work. It was only by pushing forward with despatch in the intervals between the monsoons that the walls were eventually got ahead of the sand drift. They reached their respective pierheads by the year 1881. At this epoch a disastrous cyclone occurred. On 12th November 1881, the sea swept over the breakwaters from both sides of the harbour, damaging the work to an enormous extent. Blocks of 27 tons a-piece were dismantled and flung into the inclosure, the walls were undermined by the scour (in places to the unprecedented depth of 22 feet below water) and some of the