Christchurch Drainage Board

The surveyor, Captain Joseph Thomas, chose the site for the new settlement of Christchurch in 1849, ahead of the arrival of the first planned settlers in December 1850. He envisaged a city covering around 1,000 acres around the Avon river. Although slightly raised, the site was part of a much larger area of tussock and dune covered swampland pitted with water bearing gullies and raised sand dunes.^[1] Thomas' site presented the soon to arrive settlers with two problems. First, the land had to be drained, and once drainage of surface water, the condition of the underlying land made installing drainage pipes difficult.^[2][3]

From 1853, responsibility for managing the water sodden land in the early days lay with the Canterbury Provincial Government and, from 1862, with the Christchurch City Council, although the council's responsibilities then lay only within Thomas' original city belt. In addition, from 1864, different Roads Boards undertook some drainage work as well.^[4] The original clean water soon became polluted and disease ridden as the population increased, thereby adding another problem for the newly created settlement.^[5]

The Canterbury Provincial Council, formed in 1852, had neglected infrastructure work, had built only a few open stormwater drains and little else. This presented a problems for the Christchurch City Council, formed in 1862. In particular, Christchurch was noticeably unhealthy, with residents facing water borne deceases caused by the lack of effective drainage. The council which quickly established in 1862 the Sanitary Commission and the Inspector of Nuisance.^[3] The Provincial surgeon in 1862 noted the causes of increased fever illnesses: “Undrained swamps and basins of stagnant water…; Cesspools; Surface water that was draining into the wells and the river and “generally every condition necessary for the development of a virulent fever existed.”^[3] In 1864, the CCC adopted a plan to take "night soil" to the sandhills in Bromley and establish sewerage pipes. The pipes that had to be brought in did not begin arriving into Lyttelton until 1866. Another cause of delay was that the council could not afford the pipes the new drainage, not helped by The Ratepayers Society that encouraged residents not to pay their rates.^[3]

By the 1870s, there were annual epidemics of diphtheria. In 1875, 152 people died from typhoid and this lead the CCC and surrounding road boards to meet to resolve the problem.^[3] In late 1875, the Christchurch District Drainage Act was passed, coming into effect in January 1876.^[3][6] It established the Christchurch Drainage Board with the dual tasks of land drainage and wastewater management.^[5] The Public Health Act 1876, gave it responsibility for the Board of Health. The engineer, William Clark, drew up a drainage scheme for the city and surrounds which was published in 1878.^[3] A key feature was the separation of wastewater and stormwater, underground ovident pipes and a sewerage pumping stations to take wastewater to Bromley sandhills. The first station opened in 1882 when 33.35 miles of connected sewer pipes had been laid, and many of the drains are still used in the 21st century.^[7][8] Improvement in public health was immediately apparent. The Drainage Board passed its responsibilities for the costly Board of Health to the CCC in 1885. Despite no longer having to pay for the Board of Health pipes, and managing only five pipelaying projects of its own between 1881 and 1884, the Drainage Board still ran out of money. In 1885, it did however set up the Bromley Sewerage Farm. Sewerage Stations pumped wastewater to the farm where it was treated before being drained into the estuary.^[8]

In 1901, keen to avoid an outbreak of bubonic plague that had recently reached Sydney, the CCC helped fund the laying of more sewerage pipes. It was particularly keen to end the remaining night soil collections.^[3] The dry earth pan and night-soil collection had been set up in 1877 and operated by John Brightling. Night soil collection still took place into the 20th century.^[9]

From 1882, a system was first constructed on Clark's initial plan with sewerage pipes within the original city belt; gravity took the sewage to a pump station on Tuam Street from there, it was pumped to the Bromley Sewage farm to Bromley, in an underground pipe for one and three-quarter miles to then continue along surface drains to the Bromley sandhills. These sandhills were levelled in 1882-83, paddocks were created and after simple treatment there, sewage was sent out into the estuary.^[10]

As the population grew, the Drainage Board lay more and longer sewage pipes. Pump stations were also built to serve increasingly occupied suburbs outside the city belt, such as Sydenham, Merivale and Richmond.^[11] After WW1, the Board’s area of responsibility expanded ad hoc to cope with an ever-increasing population. More pipes were laid to serve outlying suburbs and 24 new pump stations came into use between 1927 and 1931, the main two being on Woodham Road and Randolph Street.^[12] The Board's district had been about 140sqkm, with boundaries on the Heathcote River and the around the watershed of the Avon and Styx Rivers to the north. Small areas south of the Heathcote had later been added the district and Sumner came within the Board's district too in 1940. There were further minor extensions in 1951-52 and the Board's district was significantly extended in the 1980s to cover land around Brooklands and Kainga in the north. At its end the Board was responsible for around 290sqkm.^[10]

From 1949, the Board took steps to modernise the existing sewage farm. Building a new Treatment Plant at Bromley began in 1958 and it opened in 1962. A key improvement on the earlier farm was the use of two stage rather than one stage waste treatment.^[13]

In the 1980s, the Board's narrow responsibilities made it less suited to environmental issues associated with the loss of surface water.^[14] An example of the clash between drainage and environmental issues was the Woolston Cut, commissioned in 1986 by the Drainage Board to mitigate riverside flooding along the Woolston Loop of the Heathcote River by diverting tidal upstream water across a wide man-made canal, thus by-passing the loop. This resulted in saline water reaching normally freshwater areas further upstream, with devasting environmental effects.^[15] The solution later adopted was to build a barrage on the loop that only diverted water upstream at times of flooding.^[15][16] In 1989, the Christchurch Drainage Board ended as it merged with Christchurch City Council under wider local government reform.^[17]

• Christchurch Wastewater Treatment Plant