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News of the Arroyo


Runoff fouling Arroyo Seco





October 19, 2007 - The Star-News reports on the results of recent water quality testing in the Arroyo conducted by the Arroyo Seco Stream Team.


Elise Kleeman, Staff Writer


Pasadena Star-News


PASADENA - The Arroyo Seco is polluted with high levels of fertilizer runoff, bacteria and algae, officials from an environmental protection group said Thursday.

"There are extensive amounts of what we're testing for - the iron, the nitrates, the turbidity," said Andy Byrne, watershed coordinator for the Arroyo Seco Foundation.

Nitrates are a component of fertilizers, and turbidity is a measure of the suspended particles in the water, including sediments and algae.

Byrne's conclusions are based on monthly water-quality analyses of 10 locations along the Arroyo.

The data - from water samples collected this summer and analyzed at Pasadena Water and Power laboratories - is available on the group's Web site,

It shows that the river water becomes increasingly polluted as it makes the approximately 15-mile journey from where it exits the Angeles National Forest near JPL to where it meets the Los Angeles River near the intersection of the Pasadena (110) Freeway and the Golden State (5) Freeway.

Still, said USC environmental engineer Teh Fu Yen, the pollutant levels found in the Arroyo are not a big cause of concern.

"It's high, but it's not that high," he said of the levels reported by the foundation.

Even though the Arroyo Seco won't be catching on fire any time soon, Byrne said the data still show dramatic potential for improvement.

As an example, he points to a short section of the river between Brookside Park and the Colorado Street Bridge, where part of the water has been diverted away from the concrete channel and into two more natural streams.

Because of the filtering effects of the native plants and muddy stream bottom, Byrne said, "every single measurement is better after it goes through the streams."

A long-term goal would be to restore larger stretches of the river, he said.

Among the dirtiest sites detected by the group's water testing volunteers, dubbed the Steam Team, is a tributary carrying storm drain runoff from much of northwest Pasadena.

It enters the Arroyo near the parking lots south of the Rose Bowl.

"There are thousands of cars going by over there, so any pollutants are going down into the stream," Byrne said.

During September's survey, conducted after a short rainfall that increased pollutant levels across the board, it was "off the charts for E. coli," had the second-highest levels along the Arroyo for nitrates, and was "by far the highest for turbidity," he said.

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