Taming the wandering river

Early protection works

Since 1859, engineers have been developing systems and structures to protect us from Waimakariri River floods. Initially these works were isolated and blocked overflow channels but from 1922 when the Waimakariri River Trust was established more comprehensive works were undertaken.

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During the 1930’s, under employment schemes, hundreds of men armed only with shovels, picks and wheelbarrows created stopbanks and groynes along the river.

The original pine plantations along the river were also planted during the 1930’s Great Depression.
Miners, Harewood and McLeans banks blocked off the south channel so that the river was shifted to the north side of Templars Island. The South Branch of the Waimakariri River became the spring fed Otukaikino Stream which we enjoy today at the Groynes picnic area.

The protection system today

Built in the 1960’s, the stopbank on the north side of McLeans Island gave the “island” the same level of flood protection as Christchurch allowing the first recreation leases in 1969. This area was one of the first leases and was taken up by the Recreation Association of the Combined Working Clubs of Christchurch, which developed it as a picnic ground.

Without protection works the river would change course again through Kaiapoi or Christchurch. To protect people and property, engineers aim to minimize the river flood hazard through a system of stopbanks, groynes and planting. The current protection system is designed to withstand a 1 in 500 year flood.

Stopbanks are banks, which extend along the length of a river while groynes extend into the river channel and are usually armored at the river end. Stopbanks contain floodwaters and groynes and protection plantings on river berms slow flood waters so that stopbanks do not get eroded. River flood capacity is maintained by contractors who remove shingle from the riverbed for uses such as roading and concrete.

Waimakariri River - An important asset to the region