Do Rain Barrels Make Sense in Portland?

I think rain barrels are pretty much a waste of energy and resources in our climate.  They're a great idea, and in nearly every other part of the U.S., they can meet the needs of garden irrigation if they're sized right.  I guess they could here, too, but they'd have to be huge.

Here's the idea - you hook up a collection system to your gutter downspouts, so that all the water that rolls off your roof goes into a container.  During periods when your garden needs watering, you can tap into that storage of "free" water.  If you match the container size to your roof size, rainfall patterns, and garden requirements, you could take care of all of your irrigation needs with such a system.  You could also give yourself a big pat on the back for conserving treated tap water resources and diverting some stormwater from whatever treatment system it might be bound for.

The fundamental problem with this making this scenario pencil out in western Oregon (and much of the U.S. west coast Mediterranean climate strip) is visible right in the middle of the NOAA rainfall chart below.

Portland Rainfall Chart 2014

We don't get any meaningful rainfall for several months, starting around June 15 and ending around September 15.  Some years (2015) the rain stopped in early May and didn't come back until the beginning of October.  So a couple of 50-gallon rain barrels are enough to water for a week or so and extend your free water season into maybe mid-July.  But then they're pretty much useless for several months, just when you need them most.

We recently moved to Charlottesville, VA, where the rainfall patterns are quite different.  We get about the same amount of precipitation in a year, but it's evenly distributed.

Charlottesville, VA Rainfall Chart 2015

Summer thunderstorm activity is likely to fill your rain barrel every week, at least.  So that resource much more likely to be useable, and you don't need it as much since natural rain (and that uncomfortable high summer humidity) reduce the need for irrigation anyway.  This isn't an anomaly.  Much of the eastern half of the US sees a similar pattern.  Even in the arid intermountain west, or east of the Cascade mountains, there is much more frequent summer rainfall than in the west coast strip.

So unless you want to install a huge cistern to hold enough water to get you through the long dry summer, a rain barrel doesn't cut it.  And even if you install say ten fifty-gallon drums, that's only about $3 worth of water at Portland prices.  You'll have to fill those babies up quite a few times until they pay for themselves.

Urban Frog Pond

There are lots of Pacific Chorus Frogs around here.  Right now, in early February, they're getting serious about reproduction, and you can hear them croaking from nearly any suitable body of water.  Which means just about any puddle that isn't right out in the middle of the road.

When I was a kid, there was a little pond down the road from us, and I would collect one or two egg masses every spring, and raise the tadpoles in an aquarium on the front porch.  Tiny green frogs are frickin' adorable, but also the garter snakes that I would catch and observe for a while thought they were delicious.

Here, in the city, these animals aren't quite as easy to interact with as they were when I was a kid, but I want my daughter to be exposed to them.  I think if I provide a little artificial puddle, she might get to see some tadpoles turn into froglets this spring.  I've got a plastic tub, about 3 ft x 2 ft x 8" deep, and I'm going to set it in the ground next to a patch of irises in a shady part of the side yard.  I've heard frogs croaking on that side of the house lately, so I bet they'll find it soon enough.