Annieville Elementary School
Rain Garden (2010)
9240 – 112th Street, North Delta
A historic community
The community of Annieville, like much of North
Delta, used to be covered by dense forest that soaked up rainwater
like a sponge. Water not needed by the forest moved slowly through
the soil, being cleaned and cooled, before reaching Annieville’s
many streams such as McAdam, Collings, Norum, Honeymushroom, Kendale
and Knudson.
With such a good water supply, salmon thrived in
these streams, and in the Fraser River where the streams empty.
Annieville’s First Nations and new settlers alike enjoyed the
abundance of salmon in the area. In 1870, Annieville became the home
of the very first salmon cannery in BC. During its first season, the
cannery shipped over 30,000 pounds of salmon!
 Since
the 1960s, Annieville has grown rapidly. Most of the forest has been
replaced by buildings and pavement – impervious surfaces that can’t
absorb rainfall as the forest once did. Instead, rainfall runs off these
surfaces, down storm drains and straight into salmon habitat. Warm
polluted water has replaced the cool filtered water that once entered Annieville’s streams. Not surprisingly, salmon populations have
plummeted. The salmon cannery is long gone.
 Norum & Collings creeks flow through narrow corridors of remnant forest.
Most of their watershed area is now covered with impervious surfaces
such as roofs and pavement. Annieville School is in upper right corner
of photo.
One small step for salmon
In 2010 – 140 years after the opening of the old
cannery – Annieville Elementary School became home to Delta’s third
school rain garden (following Cougar Canyon in 2006 and Chalmers in
2009). The garden filters and absorbs rainwater runoff from adjacent
pavement, removing pollutants and recharging groundwater.
Here’s how things looked before the rain garden
was created (left, facing north; right, facing south):
There were a couple of sickly trees, lots of
weeds, and a storm drain that received a heavy flow of runoff from
the school driveway and parking lot.
Delta Engineering worked its usual magic,
installing an imitation streambed with highly absorbent soils, and
planting 2 healthy new trees.
Streamkeepers and Grade 4-7 students planted an
additional 300 shrubs and ground covers (purchased with funds from
Delta, the Pacific Salmon Foundation, and Coast Capital Savings).
The primary grades then mulched the entire garden with woodchips,
which maximize water absorption and also protect against soil
compaction, erosion and weeds.
Functional limitations
Budget was not sufficient to allow for relocating the
pre-existing storm drain to the far end of the garden (as far away
as possible from the water intake area). Nor is the garden large
enough (in relation to the size of the paved area that it drains) to
risk closing off that storm drain.
So instead, Delta crews installed a riser on the drain, so that
water can pool in the rain garden to a depth of 4-5 centimeters,
before it overflows down the drain. A larger garden, a drain
relocation and/or a higher tolerance for pooling would have
increased the garden’s capacity in heavy or extended rain events.
However, the garden does do an excellent job of completely absorbing
light to moderate runoff. As the vegetation grows, absorption and
filtration capacity will keep improving.
Annieville is a neighbourhood of walkers, a great many of whom
comment on how beautiful the garden looks, and how nice that it’s
functional too!
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Cougar Creek