Ōpāwaho / Heathcote River

Okay, so I'm here by the Ōpāwaho / Heathcote River, and it's pretty interesting how much history this place has. The Māori name, Ō-pā-waho, actually means 'The Place of the Outward Pā' or 'The Outpost', referring to a fortified settlement that was an outpost to Kaiapoi Pā. That pā was built on higher ground, just downstream from where the Opawa Road Bridge is now. It was apparently a really important resting spot for Ngāi Tahu people traveling between Kaiapoi Pā and Te Pātaka o Rākaihautū, which is Banks Peninsula.

This area was also a huge food source, a "mahinga kai," with things like blind eel and lamprey. Before European settlement, the river apparently meandered through extensive wetlands. I've seen some old maps, the 'Black Maps' from the mid-19th century, and they show this area was just full of flax, toetoe, raupō, tutu, ferns, and cabbage trees. It sounds like it was a really wet, low-lying area, and even higher ground would flood when the Waimakariri River overflowed. The iwi of Waitaha, Kāti Māmoe, and Ngāi Tahu had a really close relationship with this river, using it for food and transport for centuries. They'd hunt waterfowl and forest birds in the swamp forests and set traps for whitebait, flounder, and eel.

The European name, Heathcote, is pretty straightforward—it's named after Sir William Heathcote, who was the secretary of the Canterbury Association.

This river, which is primarily fed by springs near Templeton Road, flows through a lot of Christchurch, from Wigram all the way to Ferrymead, and eventually drains into the Avon Heathcote Estuary before heading out to Pegasus Bay. The Cashmere Stream is its biggest tributary, and the whole catchment area is about 100 square kilometers, extending out to Yaldhurst.

It's clear the river has faced some challenges over the years. Back in the day, it provided a lot of water for industries like wool scouring in Woolston, but that led to serious pollution until a sewer was built in 1966. Flooding was also a big problem. They tried to fix that in 1986 with the Woolston Cut, which was a 510-meter canal to bypass a long loop of the river. That cost about NZ$2 million, but it caused a bunch of trees upstream to die and banks to collapse because saltwater was traveling further up the river, killing the trees and weakening the soil. They ended up building the Woolston Tidal Barrage to help with that, which only opens during floods.

It's good to hear they're still working on it. The Christchurch City Council actually rated the water quality pretty poorly in 2020, with eight of the thirteen worst monitored sites in Christchurch rivers being in this catchment. But they've been building stormwater basins, like the Curletts and Wigram East basins, to improve water quality and manage flood risk, and also create recreational spaces. It seems to be working, because even with heavy rain in May 2021, no houses flooded above floor level, which is a good sign.