01 September 2014

Mark Pennington

Opinion: Kaitiaki – Protecting our Rivers

  • Debris screen at intake to flood management infrastructure. Photo: Mark Pennington.
  • A science-based management approach with a focus only on bank erosion, without consideration of ecological and other values. Photo: Mark Pennington.

In Māori mythology, taniwha are beings that live in the water where there are dangerous currents or rough seas, deep pools in rivers or dark caves. 

Although frequently considered as highly respected kaitiaki (protective guardians) of people and places, some traditions have taniwha as dangerous beings. Some can tunnel through the earth, uprooting trees in the process. Legends credit certain taniwha with creating harbours by carving out channels to the ocean. Taniwha are also associated with slips adjacent to rivers. It is best to avoid places inhabited by taniwha.

Māori mythology also references several gods, each of whom typically has a domain of responsibility. Some are quarrelsome, with conflicts existing at the boundaries of their respective domains. It is best to avoid these places, for fear of being caught up in the conflict. For example, if Tangaroa (the god of the sea, rivers, lakes and all that live within them) were to quarrel with Rongo mā Tāne (the god of kumara and all cultivated foods), this quarrel would occur at the interface between the rivers and the cultivated lands. Building a house in this location is potentially putting oneself in harm’s way.

There are recent examples of clashes between engineering/science and culturally-based decisions with regard to river management. Such examples include “Iwi says no to flood defence” (New Zealand Herald, 16 January 2006) and “Tough talking over flood issue” (Wanganui Chronicle, 17 March 2014). In the first of these, local iwi objected to the construction of a flood protection measure. While this construction could be shown, by engineering-based assessment, to offer flood protection to downstream houses, its construction would cut across significant cultural values.

Another example is where a marae exists within a floodplain, and the iwi seek to further develop the site and its surrounds. However, due to a significant flood hazard any further development in this area would be prone to an unacceptably high flood risk. A representative is quoted as saying that unless flood hazard in the area could be reduced, “We might as well chuck our money in the river” when considering development costs.

Both these examples demonstrate an apparent river management conflict. The scientific and cultural approaches have their own drivers and benchmarks, which are seemingly far apart. To mitigate this, several regions have adopted a co-management approach to river management, which covers sharing knowledge and resources to manage a river system in a collaborative way across these apparent conflicts, with decision making shared across different entities. There are numerous examples of successes in applying this approach; interestingly, there are also numerous examples of success in river management across apparently competing interests in areas where no formal co-management approach has been adopted.

Considering the mythology, a scientific approach to river management would endorse keeping one’s distance from dangerous currents in rivers and from dangerous seas, not because of a taniwha but because of an understanding of the likely hazards. Similarly, an understanding of fluvial geomorphology can explain changes in the course of a river (which may include uprooting of trees and avulsion) and stream bank undercutting leading to slips. While the taniwha explanation for these may or may not be accepted, the end result is the same where these effects are experienced adjacent to or within river courses. In the case of cultivating land too close to an active river system, the end result may be river bank and crop damage. It would be unwise (from a science-based perspective) to construct houses in these boundary zones – exactly as alluded to in mythology.

Essentially, river management often arrives at the same outcome whether an engineering/science approach or a culturally-based approach is adopted. The pathways to the solution may be different, but the end point can be the same.

With regard to water quality, while the apparently conflicting pathways appear different at the outset, the end point is often the same. Managing a waterway to ensure stream health from ecological perspectives generally aligns very well with cultural perspectives. Good stream health translates to an abundant food resource, often significant in cultural terms. Furthermore, good stream health is indicative of high water quality which makes it safe for contact recreation (swimming).

Current flood risk management is aimed at a wide coverage of values, as against the previously narrow focus on flood hazard only. The risk-based approach includes hazard assessment and a full assessment of consequences. Cultural health assessment is now frequently undertaken on river systems; it is interesting to note there is good overlap between this and a science-based stream health assessment or even a macroinvertebrate community index rating. Thus when a full risk-based assessment to prioritise options for floodplain management is undertaken, a similar prioritisation may be reached by taking the cultural pathway. The key to either pathway is evaluation from a broad perspective. If just a single value is considered in isolation, this is where conflict will frequently arise. The end result is a management option unlikely to satisfy either the science or culturally-based constraints.

Similarly, a waterway managed for debris accumulation, where it affects conveyance through a culvert underneath a road, may meet its primary purpose but potentially neglects other values. The result is that the destination arrived at via the science-based pathway is different to that which may be arrived at via the culturally-based pathway.

As long as the pathway followed in river management is followed to its endpoint so the assessment process undertaken is holistic and complete, the endpoint is very often the same regardless of the pathway followed. The end point could in sum be: “Stay away from dangerous waterways (avoid the taniwha), do not build in areas of high flood hazard or uncertainty in flood behaviour (avoid interfaces between gods), restore ecology (ensure food gathering) and maintain or restore water quality (make the water fit for swimming)”. The co-management approaches adopted around the country will no doubt seek to achieve these very outcomes, although it is hoped that ultimately such formal agreement will not be necessary in many instances, where all holistic river management pathways lead to the same endpoint.

Mark Pennington MIPENZ is the Chair of the Rivers Group, which is one of IPENZ’s Technical Interest Groups. The Rivers Group aims to bring policy makers, practitioners and community interests together to promote a multi-disciplinary approach for river management that reflects cultural and societal diversity in an integrated and holistic manner.