50 inches of Harvey

The home of a former City of Sequim staffer near Houston. A Mustang Shelby in the garage is just over 50" high...
The home of a former City of Sequim staffer near Houston. A Mustang Shelby in the garage is just over 50″ high…

This Harvey was no six-foot invisible rabbit.  This Harvey dropped four-feet-two-inches of rain on millions of Texans in less than a week.

When that many inches of rain land in your community in one storm, you can bet on a flood of tragic proportions.

In Texas, 1 million people evacuated and hundreds of thousands are without power, water, and/or have significantly damaged homes.  (Commentary: Although the Gulf Coast is prone to hurricanes, only 20% of Texans have flood insurance.)

You don’t need to be told that we’re very lucky in this regard here in Sequim.

50 inches is three times the average rainfall for Sequim per year—and thirty times larger than our typical large storms.

When Sequim gets 1.5-2 inches of rain in 24 hours, we see flooding.*  The infiltration systems can’t absorb that much water that quickly and what isn’t absorbed either ponds where it lands or flows into irrigation ditches and creek channels.  But within a few days, our porous soils have soaked up flood waters.

(Commentary: The number of Sequim-area residents with national flood insurance and recent claims filed for flood damage could each be counted on one hand.)

Now imagine 50 inches.  It’s about the height of a third grader.  It’s taller than a kitchen counter, a barstool, a bar, and certain very fast sports cars.

Even if taken on average, 10 inches per day for five days, it’s hard to imagine (and is not how hurricanes work).  This is a colossal amount of water to hit a saturated, flat landscape where potential outlets downstream are surely clogged with debris and more floodwaters.

ABCnews.com reports it to be 20 trillion gallons of water, enough to supply New York City for 50 years.  (Commentary: NYC and the East don’t need it.  What about how far that water would go in the arid west?)

With predictions for wetter storms and sea level rise over time due to increasing greenhouse gas emissions, flooding risks are increasing and flood insurance is more expensive.  Flood insurance has not been standard issue with homeowners’ policies for many decades, and indeed several major private insurers have scaled back or left Florida and other flood-prone states altogether.

All of which implicates the federally-funded national flood insurance program (NFIP), which is over $20 billion in debt since Hurricanes Katrina, Rita and Sandy.  Estimates for recovery from Hurricane Harvey now range from $75-160 billion.  (Commentary: Ironically, the NFIP is due to be reauthorized at the end of this month.)

How will restoration in Texas be funded?  My impulsive $10 donation at the drug store yesterday hardly made me feel hopeful, but with millions of similar donations perhaps it will make a dent.  (Commentary: Much better would be a thoughtful donation to a recognized charity such as the American Red Cross and others.)

What actually gives me hope?  Fortunately, helping others is a natural instinct, as we have seen on the news so many good Samaritans and volunteer professionals helping out in Texas.

My hope is that we help our collective future by directing more of our energy systems away from fossil fuels, toward renewables, to avoid flooding crises like Harvey over the long term.

*According to the Western Regional Climate Center’s database for Sequim, a 2-inch rainstorm happens roughly every 10 years; we’ve had six since 1980, measured at station “Sequim 2E,” the wastewater treatment plant near Sequim Bay.

Other statistics from abcnews.com.

Geek Moment:

For the 2017 water year on September 1 (starting Oct. 1, 2016):

> In Sequim, cumulative rainfall=14.9 inches (most recent rain recorded was 0.1 on August 13)

> Dungeness River at Mile 11.8, flow=152 cfs (now below typical/ long-term average)

> Bell Creek flow into Carrie Blake Park=dry; at the mouth=<0.5 cfs (1 cubic foot per second is just under 650,000 gallons per day)

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Ann Soule is a hydrogeologist immersed in the Dungeness watershed since 1990, now Resource Manager for City of Sequim. Reach Ann at columnists@sequimgazette.com or via her blog @watercolumnsite.wordpress.com. 

This article printed in the Sequim Gazette on September 6, 2017.

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