Darin Brenner

A magical vision
of water, stone, plants and lore -

 A Brook in New Zealand

by Darin Abraham Brenner
Auckland, New Zealand

Click images to enlarge

Firstly, before sharing but a small piece of the watershaping and water gardening found down under here in the "small" country of New Zealand I would like to thank WGI Online for giving us the opportunity to share with readers some creative ideas and uniquely New Zealand scenery and flora.


THE SCENE

Our project began in the quiet semi-rural estate community of Whitford, outlying the city limits of Auckland. Whitford, only a short time ago, was mostly dairy land and pig farms but now is a thriving exclusive country estate property overlooking an estuarine bay of the Hauraki Gulf on the eastern side the North Island of New Zealand.  

Our client in this project envisioned a stream with waterfalls following the length of the gently down-sloping meandering driveway. At first view the site gave me the exciting impression of a blank canvas waiting to be painted. The existing landscape was empty, having grown in with only grasses and weeds after the house construction had been finished one year earlier. The site has northern exposure, which here in the southern hemisphere of New Zealand translates to lots of sun.


There was a masonry basalt rock retaining wall located towards and to the side of the lower portion of the proposed water feature area. At first glance I knew the backside of the retaining wall would likely provide a suitable location for all the pumps and controls needed to operate and maintain the entire feature. Not only would the retaining wall provide a discreet location in which to hide the equipment and be centrally located, but also the retaining wall would greatly muffle and reduce any noise generated by the equipment.

The official "ground breaking" was in the early autumn, which for us in the southern hemisphere typically begins in April. We fortunately had about two decent months of weather before the winter storms commenced. The storms sometimes chased me off the landscape, sending me to the vehicle first and then usually home.  

  New Zealand is renowned for its inherent natural splendor and beauty of its geography, featured in recent blockbuster movies like Lord of the Rings, the Last Samurai and King Kong. New Zealand is a relatively young nation mostly dedicated to farming from north to south. The city centers contain most of the country's population, those being Auckland, Hamilton, Wellington, Christchurch and Dunedin. More than 75% of the five million or so people live in these city areas. You find most of the New Zealand landscape open natural country, some of it impacted by agricultural alterations, but much of it is either natural grass/tussock lands, coastline, or rugged mountains.
It's examples of natural New Zealand environments that I chose to incorporate into the client's landscape. The geography and geology I imagined for the stream and various pools would be snapshots taken right from the natural wonders of the New Zealand bush country. I chose to mimic streams and flowing water one might find in the Southern Alps, in particular the Otago region of the South Island, and I wanted to incorporate scenery and topography found in the Lake Taupo region of the North Island. New Zealand, particularly the North Island, is volcanic in nature with volcanic domains, mountains and geothermal activity areas abounding.  

I found it appropriate to re-create freshwater thermal artesian springs one might see in nature and did so by building, under gravel, spring bubblers/jets circulating water in the pools up to the surface. Fortunately, and much to my own interest, the client wished to use native plants for effect and to reduce the need for irrigation. I chose to go with various natives for both the landscape plantings as well as the marginal and aquatic plantings. Some were found locally. Others came from unique and exotic places in other New Zealand regions, and suited the vision I had for the client's stream and pool. 



THE CONTRUCTION

Work began in earnest by excavating the lowest pool/pond area, then moving to the pump shed area. We gradually worked up the driveway creating ledges and changes in grades to serve as waterfall locations. Finally we shaped and dug the various stream and landscape contours up to the starting pool at the top of the driveway.

Upon finishing excavation I dressed the stream bed and pond basin with a good layer of screened topsoil to cover up any minor blemishes that could put the liner at risk. The soil allowed me to contour the grade and shape details more precisely throughout the entire stream. We placed a slotted flexible drain pipe into the deepest portion of the main pool area to assist with any runoff that might collect under the liner, since most of the soils present on site were clay-like.

This project required using a durable robust liner as an earthen pond construction was out of the question. We needed something that could handle large feature rocks one to two tons each, some stacked on top of one another to act as cliffs and ledges for the waterfalls, others used singly for effect. From past experience in the United States I knew of only one such liner candidate, that being the Firestone EDPM Rubber Pondguard. This liner also holds up for decades against direct UV light and extremes in climate such as freezing and heat. We had to import it from Australia.

To increase the tensile strength of the liner we chose to underlay most of the liner with a felt-like geotextile fabric. Firestone recommends installing such an underlayment to increase the strength ratio of the liner by a potential extra 500 to 600% as weight is displaced on it. Underlayment also serves to protect the liner from abrasions and punctures. As extra protection the main waterfall area was padded with pieces of foam carpet padding, bed-like sponge foam pieces, and remnant pieces of liner. Besides the layer under the liner, another layer of underlayment was added to protect the liner from the sharper points of feature rocks, stones, pebbles and sand, and to reduce slippage of any of these materials from the slopes/inclines.

In discussion with the client, I opened up the idea of conserving water usage and reducing overall energy consumption by constructing what Filtrific LLC of the US calls "Vanishing Water". Essentially vanishing water is allowing a stream and/or waterfalls to be periodically shut off either manually by the homeowner or having routine shutdowns programmed into a timer with overflow water stored.


We used ballast tanks to store or draw water separately and in combination with the main pond. We decided to set the tanks on their own with a separate pump and connected them directly to the pond liner with two modified large PVC pipe inlets set just below the high water mark in the pond. Either submersible or centrifugal pool pumps can be used. We find pool-type pumps best suited to our water feature flow and head height requirements. They also assist us in conserving energy for the client as they last longer and are typically are more energy efficient when you need good flow and feet of head. Maintenance access also tends to be better.


Main pond

The client's house is situated in an area that requires the use of rainwater tanks and/or a bore well for domestic use. Any water garden, pond or water features is eventually going to need water to keep it at an appropriate level. To meet this challenge we needed to consider the fact he has only two 20,000 litre (5,300 gallon) in-ground concrete water tanks, no bore well, and a swimming pool in the backyard.   

The stream is approximately 85 to 90 feet or roughly 26 meters. The width of the stream varies, at its starting waterfall, from roughly 1.5 feet (.5 m) to well over 6 feet (1.8 m) before slipping into the main waterfalls above the final pool. Final maximum waterfall height above the main pool is roughly 1 meter (3.3 feet). We introduced hidden water returns in a number of places along the stream's length to give the appearance of natural downstream width increments and flows. This scale and the limited domestic water supply were the reason for using a vanishing water system.  
     
To keep the main pool's water quality and the biological health in check we use a separate pump to draw water from the skimmer tank and recirculate it to just above the main waterfall, which runs 24 hours a day and 365 days a year. This smaller pump turnover is about 70 gallons (265 liters) per minute. The larger pump driving flow up the driveway to the stream can move more than 105 gallons (397 liters) per minute. We set the larger pump to run only when the client is normally at home, in the morning and again in the afternoon, shutting down before midnight when any guests leave. Weekends are not adjusted in an effort to conserve water. By operating the stream with this schedule we not only reduce the client's pump runtime, but more significantly we avoid the heat of the day when, especially in summer, evaporation rates in the stream would be quite high.

 


To match the water loss of the entire feature we installed two autofills directly from the client's domestic water supply. The autofills are kept in check with an irrigation controller to prevent the client's domestic pump from continual or occasional on-off cycles. The water level is maintained by using float switches in combination with irrigation solenoid valves. It took us some time to properly balance the amount of water needed to maintain the water feature over an extended period of time. 
Most of the waterfalls were constructed with the natural rock slabs and pieces we found at a local farmer's quarry. We added pieces of replicated rock to give the impression of natural formations and cracks. These also serve to cover up and blend the waterfall ledges and backside seals, and to anchor the rocks more firmly. The rocks needed placing with specialized heavy equipment. We used a combination of a hired crane, a six-ton demolition excavator and, of course, my "strong lanky arms"! The pump shed was entirely constructed of faux rock over a frame as it was the only way to blend it with the scenery naturally, and yet provide a protective shell and lid for the pump and controls.  

The pond/pool area is shallow, only 400 mm (1 foot and about three inches) to meet the city council safety standards regarding fencing around deep water. We elected to keep the look of the pool open with little in the way of aquatic plants. The cobble rock we used provides a far better aquatic scene and keeps down maintenance. Besides, Otago streams are sparse in aquatic flora in faster flowing waters, except for perhaps some shoreline marginal vegetation. Streamsides in Taupo often are fairly lush, with greenery butting right into the water. Eroded soil and clay embankments and small gorge canyons are the norm. Bits and pieces of Taupo-like streamsides are incorporated into our project. It made sense to construct a bog area adjacent to the main pool that we could decorate with plants and provide a natural backdrop for the tail of the pool. The bog includes a small shallow pond and a lined soil, pumice and peat area that stays water-saturated day in day out.


THE ILLUMINATION

In an effort to reduce future maintenance we retrofitted all landscape lighting fixtures and aquatic lights with LED lamps. The LEDs have the same intensity and we could match the color hues desired and the beam angles needed. The use of either fiber optics or LEDs can be especially useful when considering aquatic lights.

Many halogen lamps supplied with aquatic fixtures can be as short-lived as one year or less, depending upon the run times. I expect the LEDs to last for more than five years, perhaps ten. By using LEDs we are saving demands on the transformer and ultimately on total energy needed to operate the system. Typically, standard low voltage lighting systems require hundreds of watts of power delivery but in the case of LED lamps we are cutting the power use by three-quarters overall. Besides the aquatic light fixtures we use some landscape light fixtures to enhance and illuminate specific points of interest such as feature rocks, a stone stream crossing, native Nikau palm and cabbage trees, and some of the waterfalls.


THE FLORA

Stream sides in the Otago region of New Zealand are sparse, almost desert-like, as the region lies in the backside "banana-belt" of the Southern Alps mountain ranges. The country in the area tends to be open tussock grasslands with occasional random twiggy shrubbery and unique expansive ground covers. I used a number of Carex and Festuca grass species to give the stream the appearance of open country and to make for interesting effects when the wind blows as it often does in this open coastal landscape.

We filled in with various shrub and ground cover species often found in the sub-alpine and lower slopes of the Southern Alps, trying to stay away from sensitive species that might not tolerate the warmer temperatures of the Hauraki Gulf. Mixed with these, we brought in native plants found in the Taupo region of the North Island and a few species naturally found in the Whitford area. These ultimately help us to tie the water feature in to the surrounding landscape for a flowing natural feel.

Some examples fitting the bill included:

Astelia nervosa
Astelia solandri 
Blenchnum penna-marina
Carex comans
Carex testacea
Carex lambertiana
Chionochloa flavicans
Coprosa acerosa
Coprosma rugosa

'Clear Water Gold'
Corokia cotoneaster
Dianella nigra
Festuca novae-zelandiae
Hebe subalpina
Libertia peregrinans Raolia parkii
< Scleranthus uniflorus
Tetragonia tetragonioides
Xeronema callistemon
 

For added interest, I found Drosera binata, a unique native carnivorous plant that suits the peat bog. Drosera binata is the only species of sundew with forked leaves and is New Zealand's largest representative of the genus. The erect leaves of this plant grow rapidly, unfurling like fern fronds and reach full size (to 30 cm [12"] tall) after the first one or two leaves. Often the first leaves are forked only once but in some forms may eventually fork six times forming 12 leaf tips or points. Plants may flower several times from late spring through to early autumn.

 

In autumn the leaves slowly wither and die leaving only the resting bud behind, which can withstand frosts and occasional snow. It is often found in peatlands, wetlands and bogs, seepages, lake margins, drainage ditches, and poor sandy or clay soils in the North, South and Stewart Islands below about the 1000 m (3300') altitude ranges.   

In the plant scheme we could not do without adding a few Russell Lupines (Lupinus polyphyllus) dotted near the stream course. Lupines are not necessarily native to New Zealand but they might as well be. They have made themselves quite at home here, especially in the foothill regions near rivers of the Southern Alps. If you ever take a drive to Mt. Cook or Milford Sound, you'll know what I'm talking about.
I also thought it would be interesting to include a number of specimens of Clemisia major var. brevis, a peculiar variety coming straight off the North Island's volcanic peak Mt. Taranaki's sub-alpine slopes. 

For aquatics and marginals we kept it simple yet aimed to convey the impression of the areas we were trying to replicate. Submerged aquatics are minimal. I used both Glossostigma elatinoides and Lilaeopsis novaezelandiae, native varieties that are often are found in close proximity to fresh water artesian springs. They form dense mat-like covers over the bottom of natural spring pools and streams. Elatinoides can also be found in some of the faster flowing cobble streams of the South Island. We added a few Eleocharis parvulus, a short variety also known as "Hair Grass" to the flowing water areas to accentuate the movement of the water and give it a nice texture. E. parvulus is a slow grower and stays bunched together, sending out runners from the main parent plant over time. It can be completely submerged or be placed on the shoreline.  
The only other submerged aquatic I thought a good candidate is the native Waoriki (Maori named) Ranunculus amphitrichus, a coriander/cilantro-looking variety which is also a very good oxygenator. It has bright green glossy parsley-like foliage on long slender trailers. Seasonally it smothers itself in tiny yellow flowers. R. amphitrichus can be planted in up to 30 cm (12") of water or marginally. 


Moving to the marginals and bog plants, species include many endemic to New Zealand but not exclusively:   

Baumea teretifolia
Bolboschoenus
fluviatilis
Carex capillacea
Carex geminata
 
Carex resectans
< Selliera radicans
Sparganium subglobosum
Sporodanthus ferrugineus >


THE FAUNA

Naturally the stream and vegetation attract a plethora of bird and insect life. Many plants we selected either were nectar-producing or flower-to-seed or -berries. We specifically chose a few species for their ability to attract butterflies, in particular, the Red Admiral and the Monarch.

Flax (Phormium sp.) often attracts the infamous Tui bird (Prosthemadera novaeseelandiae) of New Zealand. Since the feature's completion, we have noticed that a number of migratory birds visit the waters for a quick drink, but have to watch out for our client's stealthy and camouflage-colored cat! 

 

We placed some plant species such as Tetragonia tetragonioides near large feature rocks which are palatable to the indigenous lizards. Once the pond biologically balanced itself I thought it good to introduce the native fresh water mussel (Kahika to Maori) Hiriidae as they are often found in New Zealand streams. Other "mentionables" are the fresh water shrimp Paratya curvirostris, the important native fish banded kokopu of the genus Glaxias and the common bully (Gobiomorphus cotidianus). Banded kokopu are famous for there ability to leap up and over high waterfalls. 
     

IN CONCLUSION

Simply put, I hope this article gives readers the chance to learn about and hopefully visit New Zealand, and to enjoy the splendid natural beauty and wildlife the country offers. Further I hope it provides a sample of ideas, concepts and thoughts to consider, include or expand into any water feature or water garden creation. As we say here, "Good on you mate!" 


More images >

Links for additional information:

www.nzfreshwater.org - information and organization involved with New Zealand native aquatic life
www.nzpcn.org.nz - information repository for all New Zealand native plant species
www.niwa.cri.nz/ncabb/aquaticplants - research information concerning native aquatic plants
homepages.woosh.co.nz/brianquinn/index.html - New Zealand Carnivorous Plant Society
www.oratianatives.co.nz - native plant nursery specialized in rare and endangered varieties
www.filtrific.com - U.S. based; unique mechanical filtering components and patented vanishing water systems
whakaahua.maori.org.nz/manu.htm - Maori site with New Zealand wildlife photos and more
 



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