Water, Water Everywhere

Ahh, the rainy season. We here in North King County are in that magical place between Seattle and The Puget Sound Convergence Zone. In other words, no one knows what the weather will be like. Ever.

Weather systems come rolling in off the Pacific and as soon as they hit the shore the wind is forced up, cools, and drops a great deal of rain. If you get tired of our rain, remember, the Hoh River Rainforest gets perhaps 200 inches per year. In addition, the prevailing winds tend to split and go around the Olympics to the north and south. When they get back together they party. Cold upper winds get pulled down and warmer, wetter winds get thrown up, causing chaotic weather below- big clouds, more precipitation, all that.  Generally this Zone is coincident with Snohomish County, but the effects can often be felt down to the University District in Seattle and depending on wind direction can show up way up in Skagit County or all the way down to Pierce County.

According to the National Oceanic and Atmospheric Administration (NOAA)  Seattle gets 37.07 inches of rain a year on average, Everett gets 37.54 inches and Tacoma gets 38.95. That doesn’t sound like much difference, but both Tacoma and Everett are cooler on average than Seattle, so feel damper. Seattle is on the edge of the rain shadow of the Olympic Mountains. Olympia isn’t, so they get over 50 inches, and Sequim is deep in it, getting only about 16 inches a year.

So what? We all know it’s rainy. Mother Nature shows us all the time. When it falls down here we mutter and zip up our jackets; when it falls as snow up in the Cascades we rejoice, unless we have to drive the pass. And rejoice we should! That snowpack is our drinking water, our crops’ irrigation, our salmon’s environment, and our hydroelectric power. However, it will be declining over the next few decades as the average snow level rises, so we will be able to rely on it less and less.    

Seattle Public Utilities, other local utilities, and we consumers, have done excellent things in the last thirty years in conservation, driving down per capita water usage from 150 gallons per person per day to about 105 gallons. Those numbers sound high because they include all users, home and commercial, but the total consumption has gone down as well.

As I wrote in all the impervious surfaces produce hard runoff that injures the rest of our natural systems. And in I advocated for greater in-city water storage to offset the loss of snowpack storage in the future. That doesn’t have to take the form of massive reservoirs all over town, but could be dispersed household by household.

There is a rainwater collection system already in place if we want to use it. It’s called the ‘roof.’ Assuming precipitation at 37 inches per year times a roof area of 1000 square feet times 144 square inches per square foot divided by 231 (cubic inches per gallon) it will collect 23,000 gallons per year!  Rainwater collection barrels are widely available, but I’m thinking of something a bit bigger. 23,000 gallons is most of what a household needs for a year, so if each could have a filtration system it could be potable, or if that’s prohibitive blocks or neighborhoods could combine resources to purify larger volumes. In any case, no treated water need ever be used on gardens again.

There are, of course, many things we can do individually. The EPA talks about further things people can do to reduce their water usage and impacts.