mickelsp / rainfallandpipelines

Why isn't moving large volumes of storm water via pipeline feasible?

RainfallAndPipelines

Why isn't moving large volumes of storm water via pipeline feasible?

Inspired by these Tweets: "@LuluFriesdat I like the idea but could pipelines even begin to accommodate these types of storms? I don’t have the engineering knowledge to know. I agree this is the new normal & will get worse." "@jennycohn1 I would like to hear from ppl with engineering experience. We pipe massive amounts of gas & oil across the entire continent. Why not water?"

“Why not water?” It’s a good question, and in places like California, we do pump water over long distances via the California aqueduct. So why doesn’t it make sense to try to pump water from a storm like Florence? In short, the volume would overwhelm any efforts to pump it. 1/8

Here’s a rough estimate to show us why: Florence was estimated to drop 18 trillion gallons of water over 7 days ( https://mobile.twitter.com/RyanMaue/status/1040467582120337408 ) which averages to almost 10 billion cubic meters per day. That’s a hard number to wrap our brains around, but for comparison... 2/8

...the California aqueduct is basically a big water pipeline with a capacity of 370 cubic meters per second ( https://en.m.wikipedia.org/wiki/California_Aqueduct ). At 370 cubic meters every second, it would take the California aqueduct about 304 days to move all the water from one day of Florence. 3/8

If instead, we wanted to move all the water in only a day? Then, we’d need about 304 California aqueducts all working at full capacity to move the water from one place to another in a day’s time. That’s a tall order! 4/8

Additionally, where do we put all that water? Lake Mead is the largest reservoir in the United States ( https://en.m.wikipedia.org/wiki/Lake_Mead ), and even if it started completely empty, three days of Florence would fill it entirely. 5/8

Pumping it into the ocean sounds good except the storm surge during the storm makes it difficult: all the rivers in the Carolinas are basically aqueducts to the ocean, and they flood because the water has nowhere to go and backs up in the rivers. 6/8

Finally, what does a more normal storm look like? The USGS has a rainfall calculator ( https://water.usgs.gov/edu/activity-howmuchrain.php ): for 2” of rain falling over a 10-mile by 10-mile area, we still expect about one California aqueduct to take 10 hours to move all the water somewhere else. 7/8

I hope that helps. We do have a lot of pipelines in the US, but the sheer volume of water moved in, even by regular storms, dwarfs our abilities to manage it. Storm surge and high tide can be scary because they prevent normal river drainage during heavy rainfall events. 8/8