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Harvest From the Heavens

September 8, 2008

By MORGAN, Jon

Two Wairarapa farmers have found a way to turn winter rain into life-giving summer irrigation. ——————– IT’S HOSING down in Wairarapa. Rivers are threatening to burst their banks, great lakes of water are pooling on the pastures and everything — sheep, cattle, men and dogs — are splattered in mud. But Ed Beetham and Mike Southey are smiling — for them, the rainwater is money in the bank.

The chances are that in just six months the sodden scenery will have transformed into parched and dusty fields. The only moisture will be the sweat dripping off furrowed brows.

But the two sheep and beef farmers will still be smiling. They have built dams to collect the winter and spring rainwater so it can be used to irrigate pastures in the summer and autumn months. The stored water enables them to prosper in the dry when others are forced to focus on survival.

It means they can grow more grass and greenfeed, run more sheep and build up the strength of lamb-producing ewes as they go into the arduous winter months. In the sheep industry’s recent hard times this has meant the difference between handy profits and disastrous losses.

The idea of building dams to capture rainwater that would otherwise be washed out to sea sounds so clear-cut that the obvious question is, why isn’t every farmer doing it? But it is not as simple as that.

It has long occupied the thoughts of Greater Wellington regional council land management officer Stan Braaksma. His more than 30 years in farm planning have included a lot of time spent on designing dams for farm reticulation.

“Over the years, experiencing the droughts we get in the Wairarapa, I used to think, ‘Gee, there’s a lot of water that runs down the gullies when it’s not needed’.

“The idea of harvesting that water always sat in the back of my mind.”

Mr Southey, who farms at Wainuioru, east of Masterton, with wife Roz, was having the same thoughts. “It struck me that when you have a blimmin’ dry summer you’re never in control, you’re always fighting against nature. I thought about all the water that came through the farm in winter and spring and how useful it would be in summer.”

Mr Southey’s first idea was to dam a gully, but Mr Braaksma found it wouldn’t store water properly. “I got my thinking gear working and looked around for what would be an ideal site. I soon found the right paddock,” Mr Braaksma says.

To successfully store water, three criteria have to be met:

* Catchment size, which is the amount of water that can be captured.

* A suitable storage site, such as a flat paddock that can be enclosed with earth walls.

* Storage big enough to irrigate the intended area. The rule is to have 1.5 hectares of catchment for every 1ha of irrigated land.

Mr Southey’s 90,000-cubic-metre dam was built in 2003, taking water from two gullies into an unproductive basin, and he began irrigating 24ha in November the next year.

An old tractor motor pumps the water through a network of underground pipes to a K-line pod system. The pods spray a radius of 25 metres.

A year later, his neighbour, Mr Beetham, began looking around for a place for his own dam. Mr Braaksma found the ideal spot, a large shallow basin at the edge of a line-up of several gullies. When the winter rains filled it, 140,000 cubic metres were collected — enough to fill 75 Olympic-sized swimming pools.

The dams could not have been built at a better time. Wairarapa has suffered two droughts in a row over the past two summers. Though the two farmers intended the dams to be enough to take them through a normal dry summer, they have been life-savers in a drought.

“The last drought pretty much sucked the dam dry,” Mr Beetham says. Did it do its job? “Oh definitely, big time.”

The irrigated 55ha allowed him and farm manager Russell Hewson to finish lambs that would otherwise have been sold on a flat store market. It also allowed them to trade lambs — buying in the mid- $20 and selling at $60 — and later in the season they were able to put ewes and ewe hoggets on the same country to get their weights up for tupping. These stronger ewes have pregnancy-scanned at about 170 per cent, while most others in the district are at 140-150 per cent.

Mr Southey has had the same experience. “It was business as usual for us despite the drought,” he says. He finished lambs he would have to sell at store sales and did well from trading.

AgResearch scientists have taken an interest in the dams, studying the changes they make to the two farms. Dry matter production on Mr Southey’s irrigated pastures has increased by 20 per cent from November to March, a rate of improvement that was maintained even in a drought year. He also used the irrigation to ensure new pasture was well-established. On Mr Beetham’s property, the increase has been as great as 66 per cent. The quality of the pasture has also improved.

The research also found that the pastures grew better in winter as well as autumn. Their root systems had not been damaged by drought and responded to rain.

In a normal summer, Mr Beetham expects to face two or three months of dry weather. But the dam means he doesn’t have to sell lambs in late December-early January. “We can finish them, then we can trade lambs and do a reasonable job. If it’s like last season, when we’ve got four to five months of dry, we can finish that trading, and still have grass we can use to get up to speed for tupping.”

It means he is not put in the position of a drought-hit farmer whose breeding stock has been so badly affected that it takes two years before lambing percentages recover.

The cost of building the dam wasn’t prohibitive, he says. “It’s a lot less than buying another 60ha and you get the additional benefit of being weatherproofed.”

A year ago he compared farming operations with a friend at Pongaroa.

“He lost 500 ewes in the dry and we worked out that that loss, plus allowing for the effect on his ongoing lambing percentage, was enough to have paid for my system in one hit.”

The dam also saves him from extra expense. In the drought he would have had to destock at a loss and to have provided supplementary feed for his breeding ewes.

“But they are never quite good on it. You end up tupping a 55kg ewe instead of a 64kg one and it pulls your lambing percentage back. For us, that could be from our present 145 per cent to 120, which is 500 lambs less. At $60 each, that’s $30,000 lost, just like that.”

Mr Braaksma says there has been a lot of interest from other farmers in building more dams and a few proposals are on the drawing board. But not everyone has the right country for it. “I’ve been to farms and have had to walk away. They’ve got erosion, or a lack of storage or the dam would be too far away from the irrigated field.”

Shallow, flat country is needed for storage and most farmers will have to sacrifice some good land to be able to irrigate the remainder.

As the rain drums on the roof, Mr Southey, Mr Beetham and Mr Hewson sit back comfortably. It’s winter but their dams are filling with summer water.

“It’s like making baleage,” Mr Hewson says. “It’s feed being stored there and we don’t have to do anything. It’s happening all by itself while we’re sitting here.”

He describes building the dam as the “single most positive thing I have ever done on a farm”.

And, in summer, the benefits are not just financial. “It gives you a lift,” Mr Southey says, “to drive down the road and come across your own oasis of green grass.

“Having that water supply means you’re in control, you’re not scared of a dry summer, you’re not panicking, thinking you’ve got to get your lambs to the store sales before everyone else so you can keep your losses down.”

“That’s right,” Mr Beetham says. “You’re thinking positively. The extremes of weather aren’t the big worry they used to be. We’re getting all this rain, but we’re still positive, thinking, ‘This is great, we’re banking this water’.”

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