Under the bonnet with due diligence

Subject: 166 canopy hectare Vineyard development

Location: 1980 North Bank Road, Marlborough

The following is the high level detail from an investigation into the suitability of a bare land block for viticulture. Marlborough, the home of ‘Marlborough Sauvignon Blanc’ is becoming increasingly planted; the end is in sight at which point the only increase in supply for NZs most popular export wine will come from yield increases. The most popular areas, for example the lower Wairau plain, are virtually fully planted – and land values are very high at well over $200,000 per canopy hectare. So the growth is occurring on the periphery of Marlborough – up the Waihopai Valley and the upper Wairau Valley. These sites are cheaper to establish or buy (half the price), but come with increased risks – for example the risk of frost damage. The key with any significant investment decision is the measured assessment of site risk.

The following is, at least in the writers opinion, a great example of how a very good agriculturalist can assess a project and make a high quality, value creating decision. For those not aware, the premise is that a vineyard can be developed for between $100,000 to $107,000 per canopy hectare but will, on full development, be worth $133,000 per canopy hectare (independent valuation). I need to credit the work to Brian Woods of Sacred Hills Marlborough for the following.

Aspect – a good sheltered site. The large upper terrace with fall down the valley allows for the majority of this area to be planted with a north-south row orientation. With Mount Royal and Mount Fishtail dominating the sky line, this area is sheltered from the worst of the Marlborough nor ’wester. This will lower the trans-evaporation rate on the canopy over the height of summer.

To the east, a ridge separates the Onamalutu Valley from Bartletts Creek. This ridge has the effect of protecting this site from the cold easterly wind that follows the Wairau River up the valley. Further up, the Southern valleys on the other side of the river, this same protection is found. The result of less cooling easterlies is higher temperatures over flowering, leading to more consistent yields. The site has some Easy Hill. These faces will also be planted with a north-south orientation. Dry sunny faces, but still sheltered from the wind. The River Terrace is a large flat area which slopes south east, but this is only discernible due to the direction of the creek flowing across the block. This block is sheltered from the nor ‘west wind and it still receives some of the benefit of being protected from the easterly.

Soils – deep topsoil over gravels with an accessible water table. River Terrace 46 Ha. Soil type: Waimakariri. This top soil is 900mm deep and then runs into Wairau river gravels. A small ridge of these gravels shows on the surface adjacent to the southern boundary.

  • Main Terrace 80 Ha. Soil type: Kaituna. This top soil ranged in depth from 150mm to 250mm, before running into clay-bound gravel consisting of flaked schist and small quartz.
  • Back Terrace 21 Ha. Soil Type: Kaituna. The soil profile ranged in depth from 250mm to 500mm before running into clay-bound gravels. This soil had ridges with larger Fabian’s Creek stone mixed into the profile.
  • All of the above soils had gravels mixed into them at a depth of 900-1000mm, providing good drainage.
  • A pan was found in the flats running east west at the base of the easy hill country. This pan was easily broken through and will be the result of intensive grazing by cattle.
  • Easy Hill 15 Ha. Soil Type: Tuamarina. This profile ranged from 150mm-200mm before running into clay. Minimal contouring will be required to make these slopes operational. The abundant top soil will allow the stripping and contouring to take place without any impacts on fertility.
  • The soil pH was lower than desired and 3 tonnes of Ag lime will be applied.
  • The Olsen P levels were variable but 300 kg/ha of superphosphate has been applied, so re testing will be need to be carried out prior to planting.
  • All of the plantable area for viticulture has been cropped in the past and has been ploughed and worked extensively.
  • The clay component of these soils adds good water holding capacity, which will contribute to minimal irrigation being needed.

Drainage. This is a higher rainfall area and good drainage is important to allow management activities to continue uninterrupted over winter. Open drains in the side gullies, combined with significant fall from the back of the blocks to the front, sees water moving off the paddocks very quickly. Nova coil is planned to be utilized to link wet hollows to the main drains. Boundaries will be re drawn to keep drains within the vineyard boundary and under the vineyard control.

Water Consent. Water permit Uxxxx, a maximum take of 52.1 litres per second or 4,500m3 per day. The system is designed to apply the maximum of 9 litres/vine/day with 1.0L/hr drippers @ 0.6m spaced dripline (3.0L/vine/day) with 2.5m row spacings, assume 8 irrigation zones. (Average 20Ha each).

The targeted water volume per day per vine will be at 5 litres per day. This will allow for 44.44% redundancy in the system.

The development will also be applying for a class C water permit. The class C permit will have a higher extraction rate allowing for a faster dam fill. Although not strictly necessary this will add another level of flexibility to the system.

Water Storage. The property has any number of sites for water storage, but we have selected an area that has steeper contours, making it less desirable to plant. At 5.8 Ha we will have ample room for the 80,000m3 dam. This volume of stored water will allow for 8 weeks of watering at 4 litres per vine per day.

Once established, the vines on the lower 46 Ha river terrace will need minimal or no irrigation. This area will be planted in vines grafted on Schwarzmann root stock. These vines will soon establish a root system in the water table at 900mm-1000mm deep. This, combined with good management of the stored water and available ground water, will allow the dam to supply the vineyard for up to 80 days on stored water. 

Historically, Wairau class B is shut down over summer, usually for a period of a 10 days. Rainfall in the high country sees the river recharge and dams are topped up while the river is at a higher flow. The records show that in the last 50 years the river has not been below the threshold for irrigation for more than 45 days.

Telemetry. Telemetry will be installed as a requirement of the water consent. This will provide historical and live data in regards to water use.

The frost fans will also have telemetry installed to provide historical and live data from 32 sites on the vineyard.

Soil moisture probes will be installed to monitor and report soil moisture.

Flood Protection. The lower terrace is adjacent to the Wairau River for approximately 1.2 kilometres. There is 450m of stop bank already in place. We plan on extending this stop bank by another 500m. The vineyard upstream of our development has 1600m of stop bank in place, which adds significant protection to us.

A regular programme of maintenance for the stop bank is planned and willow plantings will be made to add another layer of protection.

Bartletts Creek has a stop bank in place adjacent to block Q - this is also protected by willow trees.

Fabians Creek will have a small berm-type bank constructed on the southern side of approximately 1m in height this will protect a hectare of plantings in block E.

The Council has been onsite to inspect the condition of the existing banks and to discuss the proposed works and they will work with us through the consent process.

Roading. The Northbank Road provides good access to the bottom terrace and, due to this running along the length of the frontage, minimal internal roading will be needed. Fabians Valley Road runs north - south for the length of the main top terrace. This provides access through the centre of the 80 Ha of main terrace. Bartletts Creek Road. This road bisects the large main terrace and provides good access to the back terrace.

An all-weather track will be formed to the dam site.

Roading and all-weather access is critical for the development phase and for the operation of the vineyard. These existing roads are a real bonus for this site.

Resource Consent/Permits. The dam will need a consent application. Consents/ building permits will be needed for the erection of frost fans. There are no neighbours which will affect the placement of fans. A consent to take class C water will be applied for to enable Dam filling during high flow. Class C is still available.

If practical, and subject to engineering advice, we will be diverting some drains. This will require a consent. As these drains do not flow over summer, there is unlikely to be any issues with realignments.

The process of developing the vineyard is a permitted activity and all of the above consents are part of a standard and well understood process.

Permits to convey water across the roads through the property will be required.

Building permits will be required for sheds.

Frost. The following brief overview summarises data from 3 Climate Towers at a property on North bank Road encompassing Bartletts Creek:

“Initial data suggests frost will pose a risk to the proposed vineyard development. Coolest temperatures were found at the tower located furthest up the valley and temperatures appeared to warm toward North bank Road. A detailed frost profile has yet to be completed, but data suggests minimum temperatures are higher than those recorded at Climate Consulting’s reference Wairau Valley AWS located at Wairau Valley Township by 1.0 – 1.5°C.

Inversion strengths are strongest furthest up the valley (>2°) and weaken toward North bank Road. This reflects increased air movement draining the Wairau Valley, as opposed to quite different drainage winds from the Bartletts Creek tributary. Wind machines could be expected to provide an effective means of frost protection from the majority of frost events, however, wind machine spacing should tightened to no greater than 5ha / machine over northern-most (assuming) cooler areas of the property.

Wind drift speeds were light – moderate, although marked changes in drift direction were observed reflecting cool air drainage from a number of smaller contributing gullies and valleys. Wind direction frequency analysis performed as part of the full frost report will ultimately dictate numbers and positions of wind machines.

Stu xxxx

Climate Consultant.

The fan placement plan provided by NZ Frost Fans shows 3 fans covering the cooler part of the block at present. Adjustments can be made regarding placements once tree removal has been factored into the plan.

Summary. The combination of aspect, water availability and storage matched with soil types make this site a very attractive viticultural proposition. However the data gathered by Climate Consulting confirming that this site can be adequately protected from frost events by frost fans offers the final assurance that this site can be developed and operated as a reliable productive viticultural unit.

Sacred Hill is satisfied that this site meets and surpasses what has been accepted as land suitable for viticultural development.

Maybe few that started this article got to its end – one I suspect has to love the science of agricultural and horticultural science to like this sort of thing. But it is this sort of detail and knowledge that creates economic value for investors and we are privileged to be working with our partners, Sacred Hill, on this project. For more information on the project and to order an Information Memorandum for the investment, please click here.