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Drainage of coastal lowlands in NSW

Extensive flooding on the north coast of NSW in the latter half of the nineteenth century caused large agricultural losses, fuelling calls from the community for the draining of private freehold land on coastal floodplains. The government complied. The colonial Drainage Promotion Act 1865 and later, the Drainage Promotion Act 1901, were enacted to provide for the ‘better drainage of lands’ and the establishment of drainage unions.

Although frequently justified on the grounds of flood mitigation, an additional and often primary motive was the ‘reclamation’ of dry land often by the drainage of backswamps and the exclusion of tidal waters.

The NSW Public Works Department (PWD) Annual Report of 1906 noted, for example, that ‘on the coastal rivers, there are thousands of acres of swamp lands of the richest character that need only proper drainage to make them very valuable’, and concluded that ‘the drainage of these lands appears to be one of the surest and most profitable investments on which money can be employed. It will undoubtedly be the means of inducing closer settlement of the coastal districts of the State.’

From the early 1900s, the PWD facilitated drainage by conducting investigations and surveys, and designing swamp drainage schemes (PWD Annual Report 1902). By 1907, work was in progress or applications for drainage had been made for several areas including Cudgen (Tweed coast), Belongil (Byron), Newrybar – North Creek and Bungawalbyn (Richmond), Everlasting Swamp and Shark Creek (Clarence), Kinchela, Frogmore and Seven Oaks (Macleay) and Pipeclay (Manning).

Little publicly funded drainage occurred from about the 1910s to the early 1950s due to wars and the depression. However, following major flooding in 1949 and the early 1950s, several large flood mitigation and drainage schemes began, often extending and augmenting the early drainage networks. In the lower Macleay, the Macleay River County Council progressively implemented several major flood mitigation and drainage works that continued into the mid-1970s.

Richmond River County Council (constituted in 1954) also embarked upon a major program of works, while significant construction of works by the Clarence River County Council was carried out after 1959 and through to the early 1970s.

Constructing a drain in the Macleay region, early in the 1900s.

The 1960s appear to have been the most energetic period for the construction of drainage and flood mitigation works generally. Much of this work was supported and/or undertaken by successive local and State governments, which facilitated the construction of extensive drainage systems by drainage unions and private landholders.

The floodplains of the northern rivers of NSW have now been extensively drained, with large networks of flood-gated drainage channels. These works are now owned and operated by councils, county councils and drainage unions.

Important changes in the pattern of land ownership on the floodplain occurred as a result of flood mitigation schemes and the associated activities of drainage unions and other landholders in many valleys. Landowners subdivided properties into smaller holdings, often consisting of lower floodplain land only, which generally relied on effective drainage and flood mitigation for economic viability. The main period of construction of major drainage and flood mitigation works has now passed. Coastal floodplains are under renewed pressure from both agricultural and urban development, but the main focus in agricultural areas is on redesigning existing works and alternative ways of operating control structures.

The former NSW Government undertook a significant project to map drainage networks. It not only accurately located drainage works that may have been subject to consent and licensing, but also assisted the development of acid sulfate soil management strategies for designated ‘hotspots’.