As highlighted in the recent HBRC report, one of the key challenges facing Heretaunga (Hastings, Napier and the Heretaunga plains) is how we enhance and use our water resources for the mutual benefit of the environment and our economy.
In the face of imminent climate change we are blessed with a simple and affordable solution, unlike most of our neighbours in NZ and the rest of the world. We can affordably store water in the winter when it is abundance and release it into our environment in the summer.
In the past the economy has taken preference to this unique resource at the cost of the environment, and this is not acceptable or sustainable going forward. We need to fix the environmental challenges whilst we continue to support our growers and our industry who underpin the jobs and the wealth of our region. We are in the very fortunate position of being able to do both with relatively low capital cost, this is a win/ win opportunity. We have a raft of commercial water users, some for short periods over the summer period and others for the whole year.
The challenge is that we have very strong demand for irrigation water over the summer and this affects the water table and often results in the water levels in our streams and water ways dropping, some drying up entirely. This has a negative effect on our wildlife habitat, especially tuna. We need a water plan that enables our economy to grow whilst protecting and enhancing our environment.
The current proposal is to allow water users to take water from the aquifer, albeit it at a reduced level (refer TANK) and to establish two environmental water storage schemes. One at the Glazebrook site and eventually the other at the WhanaWhana site. These schemes will create approximately 25Mcu of water storage and be predominantly for environmental use, with only small direct commercial application. I.e., we store the water in the winter from high river overflows and release it into the Ngaruroro and the Karewarewa/Paritua stream respectively. The water released into the Paritua, will pass through Bridge Pa and Paki Paki on its way to the Karamu, maintaining the streams water level in the summer during high irrigation use.
The use of augmentation such as is currently used on the Raupare, which was a brilliant initiative by the local growers should be continued and extended to other streams not directly on the Karamu. Our commercial water users need to take all their water from the aquifer, all stream and river takes need to be phased out.
The community should put up the capital and invite other interested investors such as Tangata Whenua to invest. The annual operational costs and return on capital should be funded by the commercial water users through an environmental rate. This will be a relatively small cost when put across all commercial water users. We should exclude ordinary householders and health providers from the environmental rate.
This is an easy and obvious solution to manage our water resource for our economy and our environment over the next very challenging decades. We all know that climate change is here, it is already devastating many regions of our world and we will not be exempt. If we don’t prepare now we will just sleep walk in to an economic and environmental disaster with tremendous negative consequences to our region and to the health of our people.
Wonderful to see Rex in favour of water storage .If only he and his fellow Romans had waxed so lyrical in 2016 . I wonder what changed his mind?,
WOW, Tim, your slip’s showing
The water in the aquifer is, or should be, naturally filtered and pure. It was once the best drinking water in the country. It is a resource like no other – itself an important part of the environment you talk about protecting. That is the water we need to care for – even Managed Aquifer Recharge is a risk to its purity.
Yes to small dams – but use those for the irrigators, not the aquifer, the heart of the system.
Sounds like you’re suggesting a Special Partnership relationship to me Rex. If one group contribute more they’ll expect special treatment. Enough already.
The aquifer is so interconnected whether you take from a surface/river consent or a bore is irrelevant . As mentioned in the TANK report. To the point that they acknowledge the creation of zone 1 low flow cut off is not enough.
On low flow stop all irrigation . The river will recharge more quickly . But no strangely TANK said effects to great to cut off all irrigators . Until you do that there will be no solution . Just a two tier system . Those on low flow playing there part in protect thevenvironment and those continuing to irrigate knowing they’ve got away with it again.
An alternative for the Big dam in the Tukituki river?
The most common methods and proposals to have more access to water is by building a big dam in a river, or creating holding ponds.
The same result can be achieved by building a lot of very small permeable dams in the river; they are usually called a weir. This is mimicking what a river already does. In heavy rainfall the water would build up before each small permeable dam of saw about 1 to 1.5 m high and overflow when the top is reached. When the rain stops the weir slowly releases its water, and the surrounding area upstream soaks up the water in the soil. Thus we have created a water storage that slowly releases it water over time. Now, if each than can hold the water back for a week, than 50 dams hold it theoretically back for a year. The beneficial side effects are that it reduces the chance of a flash flood and creates recreate wetlands that we have lost in the past.
If we build these weirs in the upper regions of the river catchment area, than we get the maximum benefit with the minimum amount of impact on productive land. Building each of these weirs can be done by using the readably available river stones. The stones can be held together in a net structure, or a cage. If we start building the weirs in the upper regions of the river we can slowly progress downstream while assessing the impact, and fine tuning the methods and structure.
The cost of each weirs would be very small, and the total cost compared to a big dam would be still a lot less in my estimation.
Of course such an idea needs further researching and an assessment of the local impact and possibilities needs to be undertaken.
My wife and I are very impressed with the concept suggested by Aaldert Verplanke for creating a series of weirs in our water supply rivers. Let’s work on it.
Worth a try .Be interesting to see how long the weirs would last when the river is running at 1200 cumecs .