October 30, 2011

An elegant solution to "What the #@%! am I going to do with those downspouts now?"

Creating a new rain garden and dry stream bed in Toronto

There's a new mandatory downspout disconnection bylaw  in Toronto enacted to "reduce the amount of stormwater entering the sewer system,...reducing the risk of basement flooding and releasing polluted rainwater into local waterways." Good intentions but what's a homeowner to do?

My client Christine modified this new regulation last year with my help. Originally her downspout ran away about 5' from her house's back wall and on to the lawn. This served the purpose of shedding rainwater from the roof's eaves (gutters) away from the foundation but posed hassles of a) tripping over the piece of ugly aluminum and b) not being able to run the mower over this area.

Dry stream bed with river rock, boulders and flagstone bridge by garden muses: a Toronto gardening blog
Can you find the downspout?

We discussed the idea of a soak pit by which the rainwater would be sent via a buried pipe to a leaching area. The excavated area would be covered with sod after being backfilled in order to prevent problems a) and b) noted above. But maintenance would be required periodically since the eaves often have leaves and spruce needles that inevitably would be sent to the pit and impede the percolation of precipitation.

Dry stream bed rain garden hiding disconnected downspout by garden muses: a Toronto gardening blog
My idea of a rain garden: sure beats looking at more lawn!

Another possible solution was a dry stream or river bed that receives the rainwater at grade and percolates it through the soil profile away from the house. This picture shows the finished area of about 5' long by 3' wide that connects a central circular bed (at the bottom) and the bed adjacent to the house's wall. 

I dug out a U-shaped trench increasing slightly in depth away from the house, lined the bottom with landscape fabric to prevent the surrounding soil mixing with the hardscape, added successfive layers of 3/4" drainage rock and various sizes of river rock and pea gravel. 

A rectangularish piece of random flagstone placed flush with the lawn provides a flat and safe "bridge" to cross. 

I added  (from the upper left clockwise) Northern Sea Oats (Chasmanthium latifolium), Variegated Broad-Leaved Sedge (Carex siderosticha ‘Variegata’), Siberian Iris (Iris sibirica ‘Caesar’s Brother’), Lady Fern (hidden by a yew branch lower right), and finally a "Crimson Queen" Japanese Maple that was languishing in deep shade in another part of the garden. The plants softened the hardscape and alluded to water-loving reeds.

Related to this post because we're in the same garden, I couldn't resist showing you an autumn beauty in a peaceful corner below. (You can see the same view in the summer in this post titled "A moment of rest in a Toronto garden".) 

Blooming White Pearl bugbane in front of cedar zen privacy screen and bench by garden muses: a Toronto gardening blog
Cedar privacy panel and bench lets you enjoy the 
blooming Snakeroots in peace and quiet
"White Pearl" Snakeroot (Cimicifuga syn. Actaea matsumurae "White Pearl") thrives in this area's partial shade. The white flowers don't have a scent that I noticed but getting blooms at this time of the year from a pest-resistant perennial is such a bonus. The cedar fence panel I constructed earlier makes a nice backdrop in this quiet corner of the client's garden.


  1. Anonymous2.11.11

    I like how the dry stream look just blends into the landscape. Also love the White Pearl Snakeroot. (I have the burgandy one in my garden, and it's great, but I'd never seen the white before). Very graceful!

  2. Thanks for dropping in, gardenmad. The dry stream was an interesting little project, trying to fulfill a function (proper drainage) with aesthetics. I love all snakeroots, "White Pearl" blooms really late here, a bonus in November!