24. What can we learn about New Zealand's first settlers from canal networks established around New Zealand long ago?

2.5 Canal Networks

Across New Zealand, there are significant engineering feats from past centuries, one of the most notable being the construction of canals to drain swamps for agricultural production and fish management. A few key examples of these feats are:

Lower Wairau River Canal System

In 1912, the Journal of the Polynesian Society published details of a canal system discovered in the Lower Wairau River, Marlborough. This intricate network stretches around 20 km in length, 3 meters wide, and ranges from 60 to 90 cm in depth. Approximately 60,000 cubic meters of soil were excavated to create the canals. Locals believe that their Iwi ancestors constructed these waterways.

Awanui River Canal System In 1928, Edwin Harding published details of a complex network of drains bordering the Awanui River, Kaitaia, in the Journal of the Polynesian Society. Harding noted that "almost every hollow that had once been a lake or swamp had been similarly drained." Some drains were straight and cut to the most direct outlet, with certain cuttings exceeding twenty feet in depth. The largest of these drains extended for over a mile. While many drains have been obscured by gum digging, cultivation, or drifting sand, some of the more striking works remain.

The Archaeological Assessment of Effects: Awanui Flood Scheme Effects 2019 records numerous references to this prehistoric drainage network, which has been overlaid with modern drainage channels. Drainage in this low-lying area is critical for both cultivation and flood prevention. Over time, inhabitants of the region have had to maintain this network as earlier drains became ineffective.

Both the Lower Wairau River and Awanui River drainage networks stand as examples of long-term engineering projects, initiated centuries ago, requiring substantial manpower and time, all carried out using manual methods. The identification of who carried out these projects, and when, remains unclear, as no written records were available at the time.

What archaeological features in New Zealand can you nominate where the identity of the builders remains uncertain or debated? Who do you think were New Zealand's first settlers?

Your next read in the series: 25. What DNA evidence exists in New Zealand suggesting human habitation over two thousand years ago?