The "green" Strawberry Creek by citizen reporter
The “bright green” Strawberry Creek on June 9. Photo: Linda Schacht Gage
The “bright green” Strawberry Creek on June 9. Photo: Linda Schacht Gage

If you have been walking along Strawberry Creek on the UC Berkeley campus recently, you may have done a double-take: much of the water is a bright green.

One reader, Linda Schacht Gage, was so taken aback by the color that she sent Berkeleyside the photo above, snapped on the north side of campus near University House. She asked us to investigate.

We turned to the person who knows Strawberry Creek the best (or at least has a public contact number) : Tim L. Pine, an environmental specialist at UC Berkeley’s Office of Environment, Health, & Safety.

Pine said the green comes from a non-toxic dye that is used to check the quality of the pipes that feed into the creek.

“Utility plumbers are checking for cross connections (where sanitary sewers may be attached to storm drains,” Pine wrote in an email. “These were fairly common way back in the early part of the 20th century and both the city and campus are very old.”

“The dye is nontoxic but very visible,” Pine continued. “It’s known as fluorescein dye and is used extensively to make things more visible, including the surface of the human eye!”

The testing happens a few times every week during the summer when the water level is low, according to Pine. Generally, the bright green color dissipates by the time the water reaches Oxford Street, but sometimes the plumbers have gotten the concentration of the dye wrong, causing concern off-campus when people see the water, he said. Sunlight also breaks down the dye.

It’s not the first time in recent history that Strawberry Creek has turned an unexpected color. In May 2014, the creek ran bright orange after a food-grade dye was inadvertently washed into a storm drain at the northeast corner of the UC Berkeley campus. The dye had been used by a student group as part of a Holi festival event, according to the university.

And that same month, the creek was also the subject of a “site-specific ritual performance” that involved the unraveling of a blood-red cloth into the water. Called ‘NOMAD: The Blue Road,’ the event was hosted by a collaborative of Bay Area and international dancers and musicians who supported ‘daylighting’ Strawberry Creek and other hidden urban streams.

Strawberry Creek honored, mourned in weekend ritual (05.19.14)
Strawberry Creek turns bright orange due to food dye spillage (05.04.14)
Oil spill on campus, environmental impact being assessed (12.11.11)

Berkeleyside publishes many articles every week. To see all our stories in chronological order, and read ones you may have missed, check out All the News.

Frances Dinkelspiel, Berkeleyside and CItyside co-founder, is a journalist and author. Her first book, Towers of Gold: How One Jewish Immigrant Named Isaias Hellman Created California, published in November...