Paul Kephart's Advice about the Natural Pool Conversion

Yesterday we had a visit from Paul Kephart of Rana Creek, who advised us on how we might go about building our wetland pools in stages, and answered other questions.

Paul is an interesting person, engaging yet taciturn. As if he waits for the breeze of what's going on to lift his sails, and then he's off. Paul told us how he had been up in San Francisco a couple days earlier, for the unveiling of a large living wall he designed, a mural in plants with an abstract design. He was expecting a small party. Instead Willy Brown himself (ex speaker of the California Assembly, ex mayor of SF) was the MC and lauded Paul at some length, in front of 250 people. 

This pic. is not of the SF living wall - it's part of of another wall, taken from Rana Creek's FB page.
I can't yet find any images of the wall on the net. However on the 7story blog, I read this:
The Living Wall is a collaboration between ClementinaCares, the Yerba Buena Community Benefit District and 7Story. The piece was designed by internationally acclaimed landscape architect Paul Kephart of Rana Creek, known most recently for the living roof at the California Academy of Sciences. 7Story helped shape the vision funded by YBCBD and managed the project.
It is rather exciting for us to have an internationally acclaimed landscape architect design our living pool, I confess (along with his skilled team, including Zakiah who we met when she came and took measurements and who did the meticulously detailed CAD work).

And to have him offer to drop off his concrete-cutting saw when we need to use it. He and Rat also talked about their deep and abiding love of digging. I'm sure that's not one of the things Willie Brown waxed lyrical about. Paul also talked about the uncertainty of his work in this field over the past 26 or so years. How just when the money ran out and there was no work in the queue, miraculously another contract would pop up and keep them afloat.

We delved into the nitty-gritty of implementing the wetland pools that will filter the swimming pool water to crystal clarity (we hope).

I asked about the amount of water flow required. He explained that we will be able to calibrate the velocity using a valve that switches the flow between the current system and the new wetland filtration system, such that it's enough to keep things moving but not so much it disturbs the substrate. When we get it just right, we can measure the flow by (somehow) temporarily redirecting the water to measure how long it takes to fill a bucket.

The water will come into the wetland at the bottom of the backmost pond and filter upwards, fill the pond and spill over the weir, allowing sediment to settle and be munched on by the plant roots and organisms around them, then it fills the next pool, which is shallower, and then to a narrow third pool, before it spills into the swimming pool. Everything is very low, walls just inches above ground level, and the pools excavated below ground level. (Time to call in a few favors from some young and able-bodied friends and relations!)

As far as how to break the project into stages, he said we could pour the backmost pool concrete all by itself, and then later do the next pool... and so on. He answered Rat's more technical construction questions. (I was happy that Rat was happy and forget those details.) Paul explained how we have to calculate back from the swimming pool level and lip of the final pool that pours water into the swimming pool, to get the levels right for the other pools, because our ground falls away towards the back.

Plan view of the part of the wetland pools that flows under a low bridge and into the pool (on right).

I asked about that edge, the final weir where the water flows into the swimming pool, which I couldn't visualize from the drawings. He explained where the curb would be, oh and here's an idea, just save the bits of concrete from the existing lip, cut them up carefully, and use them as capstones for the weir. Nice! We need someone with some artistic ability to give us these sorts of ideas.

Elevation of area where water flows to pool (many labels hidden, color added)

That segment of the swimming pool edge will be lower than the rest, and as we sit looking over at the wetland from the opposite side of the pool, we'll be able to look right through and into the planted area. Nice nice! Plus we won't have to drain the pool to do the work, it seems. Bonus!

Paul also looked at my small and messy wetland native plant propagation area with great delight and confirmed that I do have iris leaved rush, which is in the planting list, and a couple other things, too, and verified that the leafy thing is a weed - I'll have to compost it.

My messy start to wetland propagation. Wild ginger, Asarum caudatum, is one of the things doing well.
 The iris leaved rush, Juncus xiphiodes, and smooth horsetail, Equisetum laevigatum and tall flatsedge, Cyperus eragrostis are growing well and sprouting - I'll have to do some potting on before too long.

Equisetum laevigatum is sprouting new growth

And I have lots. LOTS. Of baby Cyperus eragrostis sprouting in the greenhouse, ready to be potted into liners today. A few anyway.

In general, Paul got us enthused and encouraged - we who had descended into a deep pit of trepidation about the size of this project and its feasibility. And he reassured us that he would be there for informal advice and involvement along the way, allaying our fears that Rana Creek would sweep on to other yet more magnificent projects and forget all about little old us!


Country Mouse said…
I do have some qualms about that sedge spreading, QBC - but our wetland is an artificially wet environment in an otherwise dry (chaparral and Mixed Evergreen Forest) area - C eragrostis grows natively a mile or two from here, but I've never seen it growing near our place. So I'm hoping it will behave itself. If not - I would look for a better mannered sedge type plant to be sure. Thanks for coming by!
This will be an amazing project! I think you made the right decision to hire someone who seems like he knows what to do.
Country Mouse said…
Thanks, Sage - I hope your comment is as wise as your name :-) - we shall see how we progress...
ryan said…
That's a great project. We suggested this to a client once, but they were too skeptical and we didn't have the confidence or experience to try to convince them. I've been wanting to see the process. It'll be interesting to see how it all works out.