To the Leni-Lenape, the Delaware was known as Poutaxat, Mochijirickhickon, and Lenapewihittuck. In the summer of 1609, Henry Hudson sailed the Half Moon into its wide mouth at the bay, and more white men — including William Penn — arrived to name and claim the water. The Dutch called it South River. It was the Swedish River to the Swedes. In 1610, an English captain was blown off course and named the river in honor of Thomas West, 3rd Baron De La Warr and governor of Virginia, a man who may have never even seen it.

The Delaware was far from pristine when Gen. George Washington crossed it on an icy Christmas night in 1776 to surprise the Hessians in Trenton. One of its tributaries, known as Cooconocon by the Lenape, ran directly through Old City in Philadelphia, where tanneries and slaughterhouses contaminated what came to be known as Dock Creek. Benjamin Franklin, in his last will and testament, left money for the city to address storm-water runoff and the fouling of drinking water. Dock Creek was eventually subverted into a sewer and paved over.

Library Company of Philadelphia A map of Philadelphia from 1800, with the city extending from the Schuylkill to the Delaware Rivers, and from Vine Street to present-day South Street.

A century later, some still found transcendence in the river.

Library of Congress Walt Whitman in 1869.

“Forenoon, crossing the Delaware, I noticed unusual numbers of swallows in flight, circling, darting, graceful beyond description, close to the water,” the poet Walt Whitman wrote in 1879. "Thick, around the bows of the ferry-boat as she lay tied in her slip, they flew; and as we went out I watch’d beyond the pier-heads, and across the broad stream, their swift-winding loop-ribands of motion, down close to it, cutting and intersecting.” Whitman came to know the river well, traveling between Camden and Philadelphia on that ferryboat.

The watershed is a source of income, drinking water, and recreation for tens of millions of people. Yet in Philadelphia, where the Delaware River runs deep and wide, it hasn’t always been a source of pride. Mostly, the river’s been a busy commercial highway here, with steel leviathans ferrying products from crude oil to cocoa beans into its ports. For many the river is simply an obstacle to cross, and worse, both a toilet and a dumping ground, at times for human bodies.

Philadelphia Water Department Historical Collection The Laurel Street Sewer in Northern Liberties, seen here in 1914, was one of many large sewers that emptied millions of gallons of raw sewage a year into the Delaware River.

The Delaware was long a killing field for aquatic life, including the prehistoric sturgeon that grew thick as logs and the once-ubiquitous shad, a fish said to have played a critical role in the Revolutionary War by saving Washington’s troops from starvation.

But a 1934 article in The Inquirer complained that the few remaining shad that made it up the river tasted like “petroleum.”