A French drain was installed at the Lincoln Memorial to protect the foundation from storm water. (Courtesy of Library of Congress)

About 70 percent of the Earth’s surface is covered in water. The human body is more than 60 percent water. A splash of water in a single-malt scotch opens up the taste considerably.

Water is important. And yet don’t you sometimes just hate the stuff?

For much of the East Coast, this spring and summer has been the Season of Rain. Last month, Washington experienced its second wettest June on record. So far this year, we’re running nearly nine inches over our typical total-precipitation level.

It wouldn’t be so bad if all those rain drops flowed in an orderly fashion: down the gutter, into the creeks, rivers and bays, and on to the sea. Unfortunately, many of them misbehave, finding their way into basements and garages. In my neighborhood, many of us dread heavy D.C. thundershowers, because we know they involve sump pumps, wet vacs and dehumidifiers.

Henry Flagg French didn’t have any of those technologies when he set out to combat the scourge of unwanted water. He was born in 1813, and they hadn’t been invented yet.

Henry was a gentleman farmer from New England. Although he didn’t go to college, he became a lawyer, like his father, who was attorney general of New Hampshire and a judge on that state’s Supreme Court. Henry would go on to practice law in Boston and serve as an assistant secretary of the Treasury in Washington, appointed by Ulysses S. Grant.

But what really fascinated Henry was agriculture. He knew that what often ruined perfectly good farm land was too much water. Draining farm fields could improve their value. French also believed that disease was caused by “miasma,” the unhealthy vapors that rose from swampy places. He was convinced that a wet basement could make you sick. It may have been that belief that inspired him to travel to Europe in 1857 after the death of his first wife. Could her consumption have been prevented if the cellar of their farmhouse didn’t regularly get a foot of water in it?

Henry visited the United Kingdom and the Netherlands. When he came back, he published “Farm Drainage.” The 1859 book is the drainage world’s “Principia Mathematica,” its “On the Origin of Species.”

In one chapter Henry wrote, “from the time when Noah and his family anxiously watched the subsiding of the waters into their appropriate channels, to the present, men must have felt the ill effects of too much water, and adopted means more or less effective, to remove it.”

Henry described various drainage techniques — the Deanston System, the Keythorpe System, the Wharncliffe System. He calculated the discharge volume of pipes of various diameters. He weighed the pros and cons of different pipe styles.

And he recommended something that has helped many of us who live in constant fear of rain: an excavated trench filled with gravel in which rests a perforated pipe to carry away surface and groundwater. He called it a cellar drain. We know it as the French drain.

I always thought the French drain was named after those people in France. No, it was named after Henry Flagg French, who once lived in a house at 137 East Capitol St.

Steve Andras , who runs a basement waterproofing company in Westport, Mass., came across Henry’s book in 2006 and became obsessed with the man and his pioneering methods.

“In order for you to understand why somebody does something, you have to understand everything about them, what kind of personality they had, what they were thinking,” Steve told me.

Steve spent seven years researching Henry’s life. He traced Henry’s footsteps in Europe, and visited Henry’s houses in Exeter, N.H., and Concord, Mass., inspecting drainage systems that Henry installed — and that still work today.

Steve even bought a microfilm set of correspondence between Henry and his brother, Benjamin B. French, commissioner of public buildings in Washington during Abraham Lincoln’s presidency.

Steve found the handwriting in the letters hard to read so he would project them on a big screen at his house. “It was as if I was watching a giant movie,” he said. “I’d transcribe every letter they wrote back and forth.”

In 2013, Steve published “French Drain for Health,” a paperback on the history of cellar drainage that focuses on Henry’s exploits.

Henry Flagg French died in 1885. His youngest son did not follow him into drainage, farming or the law. What interested the younger French was making art. He was very good at it.

How good? You be the judge: Daniel Chester French, son of the man who gave us the French drain, created the statue of Lincoln that sits in contemplative silence in the Lincoln Memorial.

And guess what was installed around the memorial in 1994 to help usher water away from the foundation. That’s right: French drains.

E before I

I misspelled the last name of D.C. restaurateur Duke Zeibert in my column yesterday. And his famous restaurant closed in 1994, not 1991.

Twitter: @johnkelly

For previous columns, visit washingtonpost.com/johnkelly.