6:39 am
  Local News
  State / National / World
  Opinion / Letters
  Arts / Entertainment
  Submit Event
  Comics / Games
  DJ Designers
  Advertise With Us
  About Us
Sewer leak contaminates popular park: San Mateo working to repair pipe, clean Laurel Creek
August 05, 2014, 05:00 AM By Samantha Weigel Daily Journal

Samantha Weigel/Daily Journal
Laurelwood Park in San Mateo has been plagued with a strong odor due to a sewage pipe that leaked into Laurel Creek more than a week ago.

Sewage traveled about three-fourths of a mile from north of State Route 92 into the creek.

A sewage leak that contaminated Laurel Creek and caused a foul odor at Laurelwood Park has San Mateo city staff working to repair a faulty pipe and clean up the environmentally sensitive habitat.

Sewage from residential and office complexes on the north side of State Route 92, just west of Hillsdale Boulevard, seeped about three-fourths of a mile down toward the popular Laurelwood Park for several days, said Gary DeJesus, deputy director of environmental studies in the city’s Public Works Department.

“When the pipe broke, sewage followed the natural drainage course of the storm system and eventually took the path of least resistance and ended up at the outfall of Laurelwood Park,” DeJesus said.

The city first realized it was sewage contaminating the creek on Friday and sprung to action. Staff immediately diverted the leak and worked through the weekend to repair the cracked 8-inch diameter clay pipe, DeJesus said.

“We were hopeful to have it repaired on Friday, but it turned out to be more of an effort than we anticipated because it’s on a steep hillside and all of the excavation had to be done by hand. So we’re expecting crews to be done [Monday],” DeJesus said.

The pipe had been likely been leaking for at least a week, as DeJesus said the city misdiagnosed the first sewage test after an initial report of a strong odor at the creek July 25.

A second report was made July 30 and another on Aug. 1, which was when further tests revealed the presence of ammonia, DeJesus said. The timing of the tests are likely proof that the leak had only occurred for a short period because it takes time for waste water to break down into ammonia, DeJesus said.

“When these sewer lines break, oftentimes they can fail all at once, but oftentimes it’s a slow process,” DeJesus said. “And it takes time for it to get to its peak of intensity so, I can’t say for certain, but it could be why it was harder to detect.”

Staff immediately began pumping water out of the creek on Friday and will continue to take daily water samples until the levels on the creek are back to normal, DeJesus said.

“If it had gone unattended, eventually sewage begins decaying and breaking down and sucks up oxygen in the water. And what you get is an oxygen deficit and it begins to impact insects and wildlife and those things that rely on the water, and also the odor,” DeJesus said.

Further plans for the park and creek, which serves as a natural drainage system for landscape irrigation runoff and the storm system for the subdivisions in the area, include planting 66 trees as part of the mitigation for the Kingridge Sanitary Sewer Line Improvement Project.

The project, aimed at preventing sanitary sewer overflow into the creek, involves replacing 1,500 feet of sewer line within the Kingridge Canyon between 36th and 42nd avenues, according to a Public Works staff report.

The project was mandated by the Regional Water Quality Control Board through a cease and desist order and began in 2011, according to the report.

The construction site was densely populated with trees and necessitated the removal of 17 trees to gain access into the canyon, according to the report.

In return, the city chose to expand the existing creek corridor by planting 66 mitigation trees within upper Laurelwood Park along the fork of Laurel Creek adjacent to the existing turf area, according to the report.

The construction related to the tree mitigation project is expected to begin in September and last through December, according to the report.

Because the trees will take six to 10 years to establish themselves, the area will be closed to foot traffic during the monitoring period to ensure the survival of the trees, according to the report.

The Parks and Recreation Commission will review the Kingridge Sanitary Sewer Line Improvement Tree Mitigation project at a meeting beginning 7:30 p.m. Wednesday, Aug. 6 at City Hall, 330 W. 20th Ave., San Mateo. For more information visit

(650) 344-5200 ext. 106



Tags: dejesus, creek, report, water, trees, according,

Other stories from today:

Sewer leak contaminates popular park: San Mateo working to repair pipe, clean Laurel Creek
San Mateo County Community College District seeks $388M bond: Funds would go toward modernizing buildings and updating labs, computers
Half Moon Bay streets to be repaved

Print this Page Print this Page  | 
<< Back
Return To Archives

Daily Journal Quick Poll
Are you planning to go to any Pride events this weekend?

Yes, up in the city
Yes, locally
Not this year
I'm passing


©2017 San Mateo Daily Journal
San Mateo County high school sports