Permanente Creek Selenium TMDL

Permanente Creek is located in Santa Clara County. It flows through a variety of land use areas, including forest, industry, open space, highly developed urban areas, and discharges to the Lower South Bay via Mountain View Slough (Figure 1). Over time, Permanente Creek has undergone significant modification, including being channelized to provide flood control functions. The Diversion Channel near Berry Avenue in Mountain View diverts most of the winter flows to the adjacent Stevens Creek.

The 13-mile long creek was listed as impaired for selenium because observed total selenium concentrations in the water column exceeded the applicable chronic water quality objective of 5.0 micrograms per liter (µg/L).

Selenium is a micro-nutrient and in trace amount is essential in maintaining cellular functions; but at elevated concentrations, selenium is toxic to organisms resulting in embryo mortality or deformities. Egg-laying aquatic organisms, such as fish and birds, are most sensitive to selenium toxicity. Dietary uptake through food webs is the major pathway for selenium to bioaccumulate to toxic levels in the body of organisms.

Map showing the locations of Permanente and Stevens Creek watersheds as well as the location of the Lehigh Permanente Quarry in red outline
Permanente and Stevens Creeks Watersheds and
Lehigh Permanente Quarry Boundary (Red Line Encompassed)

(Map courtesy of Draft Lehigh Permanente Quarry Reclamation Plan Amendment Environmental Impact Report, 2011)


Available data and information suggests that discharges from Lehigh Permanente Quarry located in the upper watershed contribute most of the selenium in Permanente Creek. The Water Board has required Lehigh to conduct numerous studies to characterize the quality of its process/stormwater/groundwater and that of the creek to further evaluate selenium loads and degree of impairment. This information will be used by the Water Board to develop a TMDL to address the impairment.

The following photos show the quarry operation and the physical condition of Permanente Creek within the TMDL project area.

Photo of the Lehigh Permanente Quarry active mining site and quarry pit
Lehigh Permanente Quarry Active Mining Site and Quarry Pit

Photo of Permanente Creek within Rancho San Antonio open space area.  The photo shows a healthy creek with riparian vegetation.
Permanente Creek within Rancho San Antonio
Open Space Area

Photo of Permanente Creek before the diversion channel near Berry Ave. in Mountain View. The creek is flowing through a concrete trapezoidal channel at this location
Permanente Creek before the Diversion Channel
(Near Berry Ave in Mountain View)
Photo showing Permanente Creek near Crittenden Middle School in Mountain View. This is also a bottom of the watershed photo where the creek is confined to a narrow concrete channel.
Permanente Creek Near Crittenden Middle School,
Mountain View (Bottom of Watershed)

TMDL Development

Staff Technical Reports (coming soon)

U.S. EPA Selenium Criteria

For more information contact:
Tong Yin, Ph.D., P.E.
Water Resource Control Engineer
San Francisco Bay Regional Water Quality Control Board
1515 Clay Street, Suite 1400
Oakland, CA 94612
Phone: 510-622-2418
Fax: 510-622-2460