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Building the Waterfall Pond |
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First, there was a Houston suburbs backyard. It had a fence around it. It had
evil Bermuda grass from fence to fence to foundation. It wasn't very exciting
to look at. Even after we dug a few little pocket borders along the back fence
and planted a few tropicalish shrubs and perennials, the situation wasn't much
improved. This garden was clearly missing something: moving water. Coming from
our Pennsylvania garden, which featured two ponds (a little one
that I built myself and a big one that we had professionally
installed, the lack of water feature was an obvious deficit in our new
environment.
So we decided we'd get a pond. It would have to be professionally installed
– I trust myself to create a rubber-lined hole in the ground (which was
basically what our PA little pond was), but not to put together the more
intricate features that make a pond really work: a bog filter, a waterfall,
attractive rock placement, and all those other niceties. Problem was, building
a pond isn't cheap, and we had just bought a house. So we hemmed and hawed for
a while, leaving the garden in its uninspiring state, until finally, in spring
of 2017 (9 months after moving in), we bit the bullet and commissioned the local
experts to build us a pond. The local experts being
Nelson Water Gardens, who
seem to be the primary pond-building gig in town. The pond was to be nominally
6 × 10 ft in dimension, with some kind of waterfall crashing down from
a bog filter. That's about as much definition as we agreed on – the rest
of the plan would have to come together as the pond was being built. We secured
a time slot in April for the project to kick off, and I secured a day off on
the first day of the project, to see how things would come together.
Early on the appointed Tuesday, the first job was to define the location of the
pond. It had to stay 7 feet away from the fence, to clear the utility easement
along the back of the yard, and ideally wouldn't cut into the swale that directs
the rain from Houston's frequent torrential thunderstorms away from the house
and yard, toward the street. The first impressions of the pond, rendered in
spray paint, looked like this:
That meant the pond would be vaguely kidney-shaped, with the filtration bog
and waterfall off the back, all placed in front of a couple of small satsuma
orange trees we had planted earlier in the year. It was positioned such that it
would be right in front of us as we opened the back door onto the patio. At this
stage, we were under the impression that the bog filter would take up the entire
area behind the pond, with waterfalls down into the main pond at a few thoughtfully
defined locations.
By early afternoon, the grass had been stripped from the projected pond
area, and efforts were underway to build concrete forms that would define the
perimeter of the main pond. All of the sod that was removed went into holes
I was concurrently digging to create new garden borders along the back fence
so that the new planting areas would be raised above the surrounding lawn
– the projects complemented each other nicely.
In the process of defining that shape, it looked like the front-to-back
dimension wasn't going to be nearly 6 ft. I negotiated some extra width, but
had to accept that the pond was then going to extend into the center of the
swale. I decided that was more than worth it: I'd deal with drainage later,
getting all the pond we were looking for was most important.
Just after the concrete rim had been poured, a big thunderstorm rolled in,
and chased the pond crew away. By the time I returned from work the next day,
they had started up again, and made a good bit of progress:
The pond shape, in all its shapeliness, is now nicely defined in concrete
(is it a kidney? is it a peanut? who knows?), and the main pond is being dug,
with soil deposited behind the project to form a raised planting area. Behind
the main pond, the area that was to be the bog was starting to take shape,
constructed from cinderblocks filled in and cemented together with concrete mix.
Two more days to go – would the project be finished on time? By the next
afternoon, a lot more has come together:
The digging is now all done, and the pond is lined in heavy black rubber.
Some of the decorative rock is also being placed – an irregular brown
rock known as "moss rock" around these parts, named for the patches of
lichen that decorate its surfaces. It is now also evident that the pond
crew's creative lead has decided to take a different approach to the bog
from the one explained to us: the bog itself is a fairly small triangular
feature at the back right, while the rest of the area behind the pond
defines a stream that carries part of the water coming down from the fall
leftways to enter the pond on the other end. While we weren't sure if the
smaller bog would meet all of the pond's filtration needs, the stream
certainly sounded enticing!
The picture above shows some more detail of the bog and stream area. The
bog in the back is filled halfway up with concrete; the PVC pipe that will
carry water up from the main pond into the bog extends to just above the concrete
bottom. Across the front of the bog several rocks define where water will
cascade down – half of it directly down into the right side of the pond,
the other half to flow through a stream that has another small bog area (the
oval ring of rocks) incorporated into it. Dirt is piled up behind this area
to just about the height of the stream.
Along the side of the main pond, rocks are being cemented in place to hide
and protect the liner. Compared to both of our previous ponds, the liner in
this one will be much better hidden, besides the obvious areas in the bottom of
the pond itelf: no ugly rubber in view above the water line.
The last day of the project has arrived. As the first order of business,
the front edge of the pond is
finished off with decorative rock, cemented in front of the liner along the
water's edge to prevent a direct view to the rubber. Then flagstones are
placed atop the entire edge assembly to finish it all off.
In another of the final touches, the distribution pipes for the bog
filter are installed: the pump submerged in the main pond discharges water
up a pipe to the concrete-bottomed bog area, where the flow splits into two
PVC distributors. Both are cut crosswise at frequent intervals along their
length to allow the water to emerge uniformly. This arrangement avoids high
velocities in the quiescent bog zone so that biosolids can settle and
be consumed by beneficial bacteria that establish themselves in the filtration
media. The distributors terminate in threaded plugs, which provide access to
the pipes for cleanout. In the next step, the triangular bog area is filled
with pea gravel almost to the top, with the cleanout plugs sticking out just a
little above. When the pump is operating, there's about an inch of water above
the gravel, gently flowing toward the waterfall defined by the flat rocks at
the left of the photo. The bog walls will be covered by flat rocks to hide the
rubber lining.
At this point, we leave the scene to go pick up some fish, waterlilies, and
other plants at Nelson's retail center in Katy. By the time we return, the pond
is operating, and almost full of water. After installing the plants, we take
the first photo of our fully functional pond:
The water would stay cloudy for a few more days, as the fine dust on the
rocks used in construction settled out. And we'd spend the next few weeks
adding a few more plants, creating a little patio area in front of the pond,
and crafting garden borders around the rest of the pond – we're not
fond of the grass-bordering-pond look. The photo below shows the look six
weeks later.
We're pleased with the way our pond is shaping up; it brings the
garden alive, and entices us to spend more time in the backyard, to feed the
fish, watch the dragonflies, toads, and water spiders, and listen to the
rush of water across rocks as we tend to the rest of the garden. While this
concludes the story of the building of the pond, I'll continue to update the
page about the pond and its plantings as the
waterfall pond continues to evolve.
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Last modified:
November 04, 2017
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