Much of the Hastings urban area was built on the flood plain. The wetlands were drained and stop-banks erected to contain the rivers and streams, protect the town and expedite the conveyance of water to the sea. Now during the summers most of us are told to preserve water, while irrigators take far more water from our rivers than our statutory plans allow for to replace soil moisture deficits. And, in places, our ground water resources are actually being mined during the summer. For several years now, record low levels have been monitored for the Heretaunga aquifer system.
In Napier, the shallow lagoons were also drained and filled in as suburbia spread outwards from the Napier Hill. The numerous roads joined all the dots, and along the motorway Napier now has to pump water up hill so that we can drain much of Napier City during medium to heavy rainfall events. There are half a dozen pumps going continuously to keep the Landcorp Farm and Napier Airport above water. Napier is fortunate that an extended period of heavy rainfall has not coincided with a severe power outage.
With the climate change scenario of rising seawater levels, the outlook is for greater saltwater intrusion inland, particularly when groundwater pressures decline. Summer low-flow periods in our rivers and lower ground water levels in the aquifers heighten the risk. Some wells put down for fresh water abstraction have come up with salt water several kilometres inland (e.g. Euchre Flats).
Many of our fresh water resources that were previously regarded as a public good are slowly but surely being transferred to private enterprise via resource consents to abstract water. What is left in the rivers is deemed to be sufficient for the rest of us, and for the aquatic ecosystem each river contains. Our rivers are supposedly managed for aquatic ecosystem purposes.
When river flows recede due to our extended summers and constant water abstraction, the remaining water warms up and the volume of algae increases rapidly. This is partly due to the concentration of nutrients that flow from the intensively farmed or cropped areas. There’s a perception that this only happens during rainfall events, but it is also induced through irrigation over heavily-fertilised pastures and crops. The nutrients flow readily through the alluvial soils and into groundwater, which continues to do its thing, flowing along underground flow paths and emerging into our rivers via springs.
Consequently, many of our favourite swimming holes ain’t what they used to be, and previously unknown (for Hawke’s Bay) species of toxic algae are becoming more prevalent. Natural biodiversity is slowly being displaced by more pollution-tolerant species.
For many years there has been a default limit on the application of nitrogenous fertilisers to land, of around 150 kilograms per hectare per year. But when you add in the amounts being added from intensive farming activity, then it is not surprising there is a steady buildup of nitrogen and phosphorus in both ground and surface waters. The control over adverse effects of activities on natural resources rests with regional councils, but there is a perception that they have been a bit lax in their duties in catchments like the Tukituki and Taharua.
Our regional plan defines a hazardous substance in accordance with the definition in the Hazardous Substances and New Organisms Act, 1996, which is:
(a) With one or more of the following intrinsic properties:
(iii) A capacity to oxidise:
(v) Toxicity (including chronic toxicity):
(vi) Ecotoxicity, with or without bioaccumulation; or
(b) Which on contact with air or water (other than air or water where the temperature or pressure has been artificially increased or decreased) generates a substance with any one or more of the properties specified in paragraph (a) of this definition.”
In some circumstances, this could be applied to excessive fertiliser use, especially if toxic algae are a result. One of our kaumatua once mentioned that the best way to monitor the effects of land use activity would be to require water abstractors to get their domestic water downstream from their property. This would guarantee cleaner rivers for the rest of us. If carried through to ground water use, we could require them to use the shallow aquifers for their water supply. At the moment, they take the clean water from the deeper aquifers and discharge fertilisers and effluent above shallow ground water and into rivers to the detriment of the rest of us.
The use of nutrient budgets for catchments has been investigated rigorously since the mid-1990’s, but due to its possible restriction on land-use intensification, has not been implemented. The use of water quality standards is also ticking away in the background at central government. They have already put out the standard for drinking water supply, but you need to be a scientist to understand most of it. In simple terms, adherence to the standard requires treatment of water to keep the contaminants below a set level. In practice, these levels often become a target instead of a maximum level and contamination is allowed to rise towards the set level. Then in some circumstances they allow for a few exceedences as well.
Water quantity is managed through minimum flows and allocatable volumes. The minimum flow for a river or stream is the “environmental bottom line” and when flows are lower than the minimum flow, water quality declines rapidly. Excessive abstraction ensures that the bottom line is reached more often and faster than previous. The control of fresh water, its management or mismanagement is causing tension not just in Hawke’s Bay, but on the national front as well. Given current trends, we may soon have to stop calling it fresh.
The main problem with water management in New Zealand is that there is a lack of co-ordination and overall direction. For our coastal marine area we have the New Zealand Coastal Policy Statement which regional authorities must give effect to, so there is the opportunity for consistency across the country. There is no parallel National Policy Statement or regulation for managing fresh water. Consequently fresh water management has been defined through regional planning and case law at the Environment Court.
The previous Labour government attempted to address the anomalies within water management through their Sustainable Water Programme of Action (2004), but they had a preference for taking advice and guidance from regional councils and industry, and the programme stalled. With the change of government, National’s direction for water management has been clearly signaled with the drama in Canterbury and the sacking of their regional council. This was clearly in response to the Environment Canterbury approach to proposals for transferring large percentages of river water to private water companies. National’s message to Environment Canterbury appears to be “stop getting in the way of progress”.
The general public and environmental groups in Canterbury have certainly made their position clear with the massive rally in opposition to the government’s sacking of a democratically-elected council, and the appointment of commissioners to speed up the water and irrigation companies’ plans.
Here in Hawke’s Bay we are just getting into this type of stuff with proposals for several dams within the Tukituki and Ngaruroro catchments, and with the Mohaka dam proposal currently on hold. A water company structure has been promoted at HBRC and the feasibility studies for the Tukituki and Ngaruroro are well underway. Further reforms to the Resource Management Act may restrict public participation as infrastructure and access to natural resources are given a higher priority than the public interest. It will be interesting to see what the Environmental Protection Agency does going forward, as they will be making the major decisions on matters deemed to be “in the national interest”. The growth in regional economies could be construed as part of this picture, especially during the current recession.
What to Ask about Water?
- Why have rivers like the Tukituki and Ngaruroro been over-allocated for water abstraction?
- Should a monetary value be placed on the water itself?
- What water conservation measures should be in place for homes, businesses and farmers?
- Should resource consents limit the use of fertilizers to protect water quality?
- Will constrained water supply limit growth in HB in the future?
- If we proceed with dams and water harvesting schemes, who should pay for them?