New Zealand: Excellent Conference WAY down south

From 22 through 25 July 2012, I had the pleasure of attending a conference in Hamilton, New Zealand titled “Recent & Future Innovations in Erosion & Environmental Control”.  The conference was sponsored jointly by the Australasia Chapter of the International Erosion Control Association (IECA) and the New Zealand Institute of Highway Technology (NZIHT). 



Map shows locations of Auckland, Hamilton, and Christchurch

Hamilton, a city of about 125,000 is located some 100km (60 miles) south of Auckland, New Zealand’s largest city.  The local area is active geologically although there have been no local volcanic eruptions in the past 5000 years.  Hamilton is the administrative center for the Waikato Region of the North Island.  Hamilton is not a city to visit for exciting night life (not my motivation for being there) or the spectacular scenery found in many parts of New Zealand.  However, it’s a pleasant place and a convenient location for observing environmental controls associated with construction of a new, badly needed, multi-lane by-pass around the city.



Riverside setting for the IECA Australasian conference in Hamilton, New Zealand

This was the fourth joint conference of IECA and NZIHT.  Maybe plenty of previous practice has taught them how to do the job right.  At any rate, the conference was very ably organized by Jill Warner, a New Zealand member of IECA, with help from Michael Francombe, the president of IECA Australasia and Sandra Lanz, office manager for IECA’s new Region Two which also includes chapters in Malaysia, India, and South Africa.  It came off flawlessly and included knowledgeable speakers, a very informative field trip, a nice venue, and lots of great food!  Also Jill made arrangements with the local Maori (indigenous) gods for heavy rains during the two days we were inside for the conference and a pleasant sunny winter day for the field trip.

The conference featured local and international exhibitors
showcasing their erosion and sediment control products

On the first morning, we were welcomed to the conference by a distinguished Maori gentleman in a business suit who spoke to us alternately in English and Maori and acknowledged both the Creator and the Maori ancestors.  He also spoke of the history of the area.  We learned that Maori rights in New Zealand had been guaranteed by an 1840 treaty with the British settlers.  However, the settlers subsequently violated the treaty and illegally appropriated Maori lands.  Recently, the Maori (who make up about 15% of New Zealand’s population) have used the courts to regain some of their traditional lands and win compensation for other lands which they lost.

Keynote Speaker – Day 1:  Sustainable erosion control

President Michael Francombe, an Australian, introduced the keynote speaker and couldn’t resist some light-hearted jabs at the New Zealanders regarding the Aussie – Kiwi (New Zealander) rugby rivalry.  The keynote speaker, John McCullah is an erosion control and stormwater management consultant based in Redding, California who specializes in training.  John is well known in the erosion control industry for his entertaining but very educational series of “Dirt Time” training videos (www.watchyoudirt.com).  Recently, he has worked with CALTRANS helping them implement the U.S. Clean Water Act and stay out of trouble with California regulators.  John operates under a philosophy of “dirt is good” as long as it’s properly managed.  

John presented his “sustainability triangle” which emphasizes the interrelationship between water, soil, and vegetation.  In a sustainable system, of course, these three elements are in balance.  But, for example, when you strip the soil of its natural vegetative cover, raindrop impact erodes the soil as simply shown by the US Department of Agriculture’s cartoon film, Junior Raindrop, which dates way back to 1948 (John played it for us). 

[I’m writing this as my Bali – Hong Kong flight passes over the island of Borneo and crosses the equator.  It’s been a considerable visual diversion for nearly 2 hours.  Now that we’re out over the South China Sea I can continue.]

Here are some good points about sustainable erosion control that I picked up from John’s presentation:

- Mulching a disturbed surface is the best type of erosion control
- Imprinting is a better form of surface roughening than track walking with a dozer.
- Compost blankets, berms, and socks are 97% effective in controlling erosion.  They can hold 10 times their weight in water.
- Using dead tree trunks is an effective and more aesthetic replacement for riprap.
- It’s important to set the stage for natural succession by planting native grasses.
- Successful use of native grasses increases infiltration minimizing impervious areas.
- Landform grading (working along the contour) creates natural, curvilinear slopes.

Sustainable erosion control meets stormwater quality standards and minimizes costs by:

- creating long-term soil health
- providing locally-appropriate healthy plant communities
- achieving permanent soil stabilization.

John talked about and showed slides from the Lucas Creek stream restoration project that he worked on in a northern suburb of Auckland.  In a later post, I’ll have more to say about the project which I visited for a couple hours prior to leaving New Zealand for Australia.

John mentioned a couple of useful references:  Landforming by Schor and Gray (Wiley, 2007) and the erosion control manuals found on the CALTRANS website (www.dot.ca.gov).   He can be contacted at john@salicaec.com.  My only complaint about his presentation was that it contained so much useful information that my brain had a hard time keeping up!

“Dirt Man” John McCullah fires up conference participants

Keynote Speaker – Day 2:
Rebuilding Christchurch after the big quake

The keynote speaker for the second day of the conference was Greg Slaughter with Christchurch Rebuild.  You may recall that the city of Christchurch (largest city on New Zealand’s South Island) was devastated by a major earthquake in February 2011.  Grey described the quake and the damage it caused.  He also gave us a sobering but positive assessment of the progress to date in repairing some of the damage.

The city is not located on a major fault, and the shallow earthquake occurred on a previously unidentified, buried strike-slip fault.  As a result of the earthquake, the city’s location has moved slightly to the east with some areas moving up and others down.  The city is underlain by fine, unconsolidated volcanic sediments which liquefy during shaking.  The city’s building codes allowed for shaking but not for liquefaction.  The codes have now been changed as a result.

The city’s natural drainage patterns changed as a result of the earthquake.   Sewer mains were destroyed resulting in some 90,000 meters³/day of raw sewage initially discharging to local streams.  For a couple months following the earthquake, total suspended solids and fecal coliform levels went way up in these streams.  Fuel and chemical spills resulted in contaminated land issues which were addressed by a site management plan.  Parts of the city were left with a high water table.  Dewatering efforts with well points using sand filters appeared to work well at first but they were soon clogged by the fine volcanic sand.  Fortunately, most of these environmental impacts were only temporary.   

The clean-up and reconstruction effort is costing some NZ$2 billion (US$2.5 billion), a hefty sum for a country of less than 5 million people.  It includes repair or reconstruction of around 1000km (600 miles) of streets and highways and 100 bridges.  The aim of Christchurch Rebuild is to create a resilient infrastructure that the local people can feel confident about.

Perhaps there was one positive effect of the quake and its aftermath:  It has brought the people of Christchurch together and involved them in the clean-up and reconstruction effort.   It also provided an opportunity to introduce sustainable design into new construction and adopt a policy of waste minimization.  The knowledge gained from the quake and clean-up is being shared with Japan and California.

Other featured speakers

Amanda Davis from URS spoke about a power cable trenching project in New Zealand which had issues with dewatering, water crossings, and water pH issues.  Staff environmental trainers faced some communication challenges because a number of the workers were from the island nation of Tonga in the South Pacific and English was their second language.

Fiona Montfort from HEB Construction spoke about New Zealand’s 1999 erosion and sediment control guidelines.  She pointed out that some required mitigation measures often cost significant dollars (yes, they use New Zealand dollars not Pounds) for minimal environmental benefits.  She also emphasized the need for early contractor involvement when planning environmental mitigation on projects.  Construction personal often understand how to construct better environmental mitigation measures for a given situation rather than going strictly by the book.  They can also help find cost-effective solutions as well as helping price out costs for environmental measures.

Craig Redmond with the New Zealand Transport Authority in Christchurch spoke about the challenges in developing a national erosion and sediment control standard as mandated by the Resource Management Act of 1991.  He pointed out that a national standard needs to allow for regional variations.  He pointed out that standards are often too rigid whereas guidelines encourage innovation.  Therefore, a combination of general standards with more specific guidelines works well.

Graeme Ridley (RDE Ltd.) spoke about the Long Bay Development Project.  Some of the innovations they used were baffles and reverse slopes within sedimentation ponds, double primary spillways, fore bays with 15% of the pond volume, monitoring using automated samplers, and silt fence as a last line of defense.

Michael Francombe (Landloch) talked about his frustrations with contractors who keep relying on the same methods after repeated failures.  In particular, he chastised the mining industry for its failure to learn from past mistakes.  He also said there is generally a poor knowledge among contractors regarding the science of revegetation.  Michael noted some of the differences in the quality of erosion control on construction projects among the various Australian states.  Whereas New South Wales (Sydney is the state capital) has been a leader in erosion and sediment controls since the 1980s, the state of Victoria (Melbourne is the state capital) is “abysmal”.    

Michael Francombe provides an Australian perspective on erosion & sediment control innovation

Jake Crawford with HEB talked about wind erosion on “roading” projects (that’s “highway construction” to you Yanks).  Instead of spraying exposed surfaces with water, longer-lasting alternatives are spraying with soil stabilizing polymers which form a crust, magnesium chloride, hydromulching in sandy areas, and use of agricultural bio-solids (which he referred to colourfully as the “Power of Poo”).  Jake warned us to watch out for suppliers of these products who call for higher application rates than are needed.

Robert Coulson with Rural Supply Technologies Ltd. talked about stream erosion and the “green fix” (i.e., bioengineering).  Stream rehabilitation which makes use of “living walls”, compost blankets, created floodplains, and introduction of riffles with well-placed aggregate is typically longer-lasting, cheaper, more aesthetic, and lower impact than using traditional structures like gabions which often fail.  Communities are also more likely to support green fixes.

There were about 15 other speakers including me.  I presented a report of my reconnaissance last July of erosion problems in a mountain community in Ecuador.

First slide of my presentation on Erosion in the Andes

Kiwis say “seediment control”

Since the conference featured both Australian and New Zealand speakers, I had fun trying to pick out some subtle differences in their respective accents and word pronunciations.  Here are some observations I made about Kiwi pronunciation or at least this is the way some words sounded to my Yankee ears:

- Check dam sounds like cheek dam.
- Trench sounds like treench.
- Sediment sounds like seediment.
- Hay bales sounds like high bales.

I’m not saying that Kiwi pronunciation is “incorrect”.  Au contraire, I find it rather delightful.  And God knows, the Queen must cringe when she hears us Yanks butcher Her English.

In my next post, I’ll include photos from the conference field trip which gave us a chance to look at erosion and sediment controls on the Hamilton by-pass construction project.