Sustainable Scientist

So, if global warming were to happen over the duration of one storm event, I’d say I’ve some small taste of the plight of coastal peoples. Last weekend in the Pacific Northwest it turned cold. So cold that Saturday we took the bus instead of riding our bicycles to the Urban Craft Uprising event held downtown at the Seattle Center.

I’d been feeling like snow for days – that feeling, growing up in the Great White North, of the prescience of snow. Well, lo and behold if it wasn’t snowing when we walked out of the craft fair! Great fat flakes drifting wetly to the ground, accumulating as slush on our naive streets and sidewalks. Cold, but what joy they brought! I sang every song I could think of containing the word ‘snow’ while we commuted to and from bus stops.

By Sunday morning the snowflakes had turned to slushgobs – slush fell from the sky, for hours. And by Sunday night gusting winds had brought a new front through and it was rain falling from a warm sky. And it fell and fell and fell, sometimes softer but mostly harder. A record rainfall of 5 inches fell in the heaviest 24 h of the storm. (For context, we get an average of 37 inches of precipitation per year, so Monday alone we got 14% of our annual rainfall!!)

‘All rivers lead to the sea’. Well, in urban environments all storm drains lead to the sea. Storm drains work like this: Water running on pavement falls through the metal grate of the storm drain and flows into a stream/lake/ocean. Pretty simple. In rural areas, the ground is permeable and acts like a sponge. When it rains the ground soaks up water until it is saturated, and then leaks the rainwater to streams over time. In unpaved areas, a big storm will increase water flowing in a river, but the peak flow is delayed depending on how saturated was the ground-sponge, and never reaches the levels it would in urbanized areas.

Pavement makes the ground impermeable to water. When there is a lot of pavement, e.g. urbanized areas like cities, there is no ground-sponge. Rain falls on roofs and pavement, collecting particulates and chemicals, and the cocktail rushes via storm drains into rivers. Streams in urban-impacted areas are ‘flashy’ – all the stormwater rushes in over a short amount of time leading to regular scouring of the stream bed (bye-bye salmon eggs) and high rates of erosion that can make the stream inhospitable to most aquatic life. I know – depressing. But educate and act, I say.

We got to see some of the downstream results of this process during the storm on Tuesday. Those of us living by ‘agua salada’ also contend with tides. As many of you know, our little fisherman’s cottage is perched directly on an old dock under which the tides rise and fall twice-daily. High tide on Tuesday was predicted for 12:17. By noon, the tide had reached the rafters of the dock. Our neighbor Judy’s dock (and by extension her house) was flooded. At its peak, the water had reached 6 inches below the dock and I could hear it lapping at our base boards. Had one of the big ships passed we would have been salty.

The weather broke in the night and this morning found blue skies and brisk winds. I went out to take a photo of the full rainbow that had formed over the mouth of the ship canal. Standing talking to my neighbor Dan, I glance down and see someone looking up at me from the water, now 4-feet below the dock on my left. It’s a harbor seal! I’ve never seen one so close up – it’s sleek grey head is streaked with dark marks. It’s obsidian eyes stare back at mine, nostrils opening and closing. It’s hard to tell if he is considering me in the way that I am considering him or if he is merely confused from all the turbidity and contaminants polluting his usually pristine home. After nearly a minute, he slips back down into the murk of the storm-stirred brackish water. Normally, this water is almost painfully clear, each pebble eerily outlined when the sweet and salty waters are mixing. But today, when the seal melts back into the water, he is gone.