Wednesday, March 14, 2012

Slipping away in New Zealand

When I arrived in New Zealand in September 2011 for a visit, the first place I went was to spend a few days visiting one of my sets of host parents (there were four altogether) from my exchange 17 years ago.  I spent Christmas 1994 with them at their bach at Omaio. As we passed through Ohope, they pointed out the land they'd bought to build their retirement home on--this is the home I visited them in.
Whakatane, on the North Island. Ohope is over the hill from it.
Whakatane and Ohope are in the Bay of Plenty, a gorgeous part of New Zealand with a great climate. The two are separated by a headland.  From the top are fantastic views, but like many headlands, the tree-covered slopes drop pretty steeply down to the beach. And this is the problem.
Ohope Beach
The headland separating Whakatane (left) from Ohope (right).
For some reason unknown to me, the land at the base of the headland, and at the base of a lot of the cliffs in the area, is zoned for housing. People want waterfront property, and they pay big money to build homes here.  Which is all very well, unless it's a wet year. Because in a wet year (and there have been a few of those lately) the cliffs become very unstable.  This has had disastrous results. Homes have been destroyed, and in 2011 a teen was killed in his home by a landslide.

Scar from a recent slip in Whakatane

One afternoon my host parents and I went for a walk along the beach, past several scars from landslips. (Thankfully, their property is not at risk of being buried). It was devastating to see the damage to some of the homes. I didn't have the heart to photograph the homes, because at least one of them belongs to friends of my host parents.

Cliffs behind Ohope Beach. Anything not green is the site of a landslide.
Just out of this photo, to the left, a house was destroyed by a landslide. Fortunately no one was hurt. You can see the big scar at the end of the beach, and another smaller one behind the house.

A big slip at the end of Ohope Beach. Fortunately, the only thing wiped out was a  footpath. My host father is standing at the base of the cliff just left of center.
Besides the fact that the slopes are unstable, from what I can tell the hillsides are loosely consolidated sands and/or paleosols (I wasn't about to go digging around at the base of one of the slips). This is obviously a huge problem, made worse by the pohutakawas (the beautiful North Island "Christmas tree" that blooms red in December). Their gorgeous blossoms don't make up for the fact that they are a bit of a nuisance plant. Their roots don't go deep, they spread out, so that instead of stabilizing the slope they weaken it close to the surface. With heavy rains/runoff, it's a deadly mix.  Come to think of it, I wouldn't want to be at the base of one of these cliffs during an earthquake either.
Part of the problem--the pohutakawas