The Aqueduct: Success at last?

Last week I was in Quebec City for the annual symposium of the Garden Writers’ Association. I met many interesting people from across North America (and one or two from England and elsewhere) and saw some private gardens that had much to offer. I visited some public gardens, some I hadn’t seen for years, and one I’d never seen before. I’ll write about these gardens, the people I met and the things I learned in the weeks to come.

But for now, it’s back to the aqueduct and the BIG ANNOUNCEMENT.

I think it is working! I think we have solved the myriad problems that plagued this project since the end of June. I can’t write this unequivocally, I hesitate even to think it, since I don’t want to jinx what now appears to be working well. But definitely water is flowing as it should.

The shrubs will eventually spread to cover the slope beyond the reflecting pond.
I will prune the boxwoods into round balls: little green drops of water.

My last post about The Aqueduct was a over a month ago, on July 22. Since then, we’ve proceeded systematically to check the source of each possible problem. For the second time we dug around the small pond that feeds the aqueduct. We relined the sides with clay. That seemed to do the trick. So I breathed a sigh of relief and sat back to enjoy the view.

Too soon. The pond held water perfectly — until the water rose to the finished height. At that point, the pond began to leak again, with water finding a way down the hillside underground. So once again we removed the rocks and the newly planted grasses that surround that pond. This time we raised the ground level a few inches and brought the clay higher up the sides.

The aqueduct holding pond gets re-lined with clay.
This is a very messy job.

This is a very messy job, particularly when you are working with pure clay and not clay mixed with rocks. (Although that isn’t much fun either.)

Messy boots, caked with clay.

The large culvert visible at the bottom of the pond allows us to drain the pond. We have to do this to ensure that water can flow freely underneath the ice in winter. But obviously the opening has to be covered for the pond to fill. Once the pond was relined, it became clear that the cover for the culvert wasn’t doing the job. We replaced it using an old-fashioned technique — a wooden plug that swells when wet. A local woodworker made the cover in a day. (Thank you, Greg!) It fits snugly into the 12″ hole and seals the gap.

We’ve had almost no rain in recent weeks so filling the pond took some time. After a few days, though, water began to flow. At first it was only a trickle.

Hooray! Water is flowing from one channel of the aqueduct into the next.
Finally.

The water falling into the basin pulsed, a heavier flow alternating with a drip, as if the water was mimicking the heartbeat of the earth. I didn’t know why the water pulsed. Was it caused by an unevenness in the steel channel? by the angle of the steel?

Then one night it rained, and the water flow increased, reducing friction. Suddenly, The Aqueduct was working! No pulsing, just water falling gently, as I had hoped.

Look closely and you’ll see water falling from the upper
and the lower channels.

There are minor issues to work out. The effect of the wind, for instance. The wind was blowing fairly hard when I took the photo below. When this happens, water is blown around. Not a problem, really, just something to be aware of. With more volume, though, when the water falls into the basin, it splashes back onto the wooden posts. This is not good — water on wooden posts means rotting wood. So in the weeks ahead, we’ll experiment, finding a visually pleasing way to direct the water away from the posts.

Water catches the wind as if falls from the aqueduct channel into the top basin.
We need to stop it splashing backwards into the wooden posts.

We need to correct the sinkhole that has appeared in one small section of the gabion wall.

A sinkhole appeared in the top of the gabion wall.
A few rocks and some dirt should correct this. I hope.

We’ll try to level the stainless steel lip, where the water exits, so that it flows out over the entire length of the lip rather than leaving one small section dry.

The section of the rill at the top of the photo remains dry.
We should be able to adjust this so that water flows over the entire length.

These are important but minor issues — they reperesent the fine-tuning that any large project requires. For the next month, I’ll simply enjoy the view. I’ll admire the interplay of clean lines.

Straight lines step up a steep hillside.

I’ll marvel at the softness of green grasses against the weight of rusting metal.

The ornamental grass is sporobolus heterolopsis.
It will change to a beautiful golden glow in the fall.

I’ll watch the flowers grow,

I had doubts about the perovskia but am liking it more and more —
particularly since it has been blooming for almost a month.

and wait for the cedar on the wooden planters to weather to the same grey as the steps.

The wooden planting boxes replace a railing and offer another spot to grow flowers and herbs.
The wood will change to a soft grey as it weathers.

I’ll begin to think about the final element of the project, re-designing the small pool where the rill ends.

The style of this pool no longer works with the clean, contemporary lines
of the aqueduct. We may add a coping, maybe a seating platform.
Ideas, anyone?

But mostly, I’ll keep my fingers crossed that the aqueduct continues to flow. It’s been almost a week now without problems. Long may it last!