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| After draining, the edge had to be cleaned and prep'ed for new work. |
With too much liner showing and a concrete retaining wall which wasn't wearing well either, we are draining the pond for re-working. Even though the liner and concrete wall were underwater when the pond is full, they could be redily seen through the clear water. With good weather and a bunch of new rock, the time had come to fix it.
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| A 'not so dry run' of new creek. |
At the
FrEdLey residence, as with all my ponds, they are primarily functioning water collector systems, but with aesthetic and habitat features often more noticable. And when you add
Fran Abel Landscape Design into the mix, the aesthetic component becomes so overwhelming that often people don't realize it's a functional and necessary water collection system.
It all starts at the upper pond where we collect the water from all three roofs (242,000 gallons per year) and any surface water runoff. However, with the healthy soil, mulch and bountiful plants, there has been no surface water to speak of since completion of site work two years ago.
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| Upper pond where water collects. |
From the small upper collection pond, the water travels down a stream between the buildings to a larger pond. This larger pond then drains to an adjoining fen or wetland where the water can linger until it is absorbed by the earth.
Everything works and looks great. The reason we're renovating the lower ponds is mostly because of water clarity. It wasn't until this summer that we began running a pump to have water in the stream when it wasn't raining. This water is drawn through a simple filter of PVC pipe with holes buried under pea gravel. Although simple. it works so well that our water has become crystal clear. Too clear, highlighting more than the fish!
So we've done two things. We've extended the stream up to the vegetable garden so that water from the ponds can be used for irrigation, and we've renovated the edges of the large pond to accommodate varying water levels and to provide more visual interest for viewing as well as a more natural lining for our Koi.
A little lesson in absorbtion.
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New stream extension between greenhouse
and upper pond. |
In order to do the work on the lower pond, we had to pump out most of the water. We pumped the water into our new (still unlined) creek bed over a three day period (it kept refilling with rain!)
Here is what we found. Our pump, by the way is modest, moving only 300 gallons per hour.
On the first day we pumped water for 6 hours lowering the main pond by 18" moving a total of 2200 gallons. Though the new stream is 30' long, only half of it ever saw water. It just vanished into the sand.
On the second, day we pumped water for 3 hours moving 1100 gallons of water. Interesting that the land had lost much of it's ability to absorb water from the previous day's pumping and the entire stream saturated and began to overflow into our upper pond. One day later, half the water and way less absorption because the soils were already saturated.
On the third day, we only pumped for 2 hours, about 700 gallons and the stream immediately began to overflow. Absorption had now entirely diminished.
What this says to me is even with sandy soil that appear to initially have superior drainage, watch out! The ground can become saturated quickly.
So even if you have loose sandy soils, if it's saturated and if there's hard pan (clay layer) below and when adjacent compaction prohibits lateral movement, then in floods, onto the streets, into the storm drains and out into the sound.
And shouldn't this water be dealth with on site anyhow? After all, the site was handling the water prior to clearing and building
At FrEdLey, this was our goal and the pond was designed to have a variable water edge and when it floods, it does so into a controlled wet land (fen) where the water can linger until the ground can absorb it, regardless of what's happening at the neighbors.
