For several years the Arroyo Seco Stream Team has been collecting water quality data at various key sites in the Arroyo Seco. These wonderful volunteers are providing an invaluable service because water quality monitoring is a key tool to improve the health of the Arroyo Seco watershed.
The water quality data collected will:
Seasonal monitoring is essential for an accurate assessment of the water quality of the Arroyo Seco because the ecological life of the watershed varies with the seasons. Changes in weather conditions have a great influence on water quality. Heavy rainstorms in the winter and early spring introduce large amounts of pollutants due to runoff. In the summer, reduced flows and higher temperatures caused by dry weather alter the conditions. Baseline monitoring data (chemical, physical, biological) are necessary to identify vulnerable areas to be targeted for improvement.
Water quality in the Arroyo Seco Watershed is degraded in several significant ways. The Hahamongna Basin is a Superfund site due to the presence of volatile organic chemicals and perchlorate. Nitrates from past agricultural practices and septic tank systems are a significant factor in some parts of the watershed. Street runoff from throughout the watershed pollutes the Arroyo Seco stream with trash and contaminants, and the Los Angeles Regional Water Quality Control Board has detected unacceptable levels of coliform from animal waste.
2006
June 2007
July 2007
August 2007
September 2007
October 2007
November 2007
December 2007
January 2008
February 2008
March 2008
April 2008
May 2008
June 2008
September 2008
2007-2008 Summary
Confluence - The site were the Arroyo Seco joins the Los Angeles River near downtown Los Angeles.
North Branch - A major tributary which flows through Sycamore Grove Park in Northeast Los Angeles.
Golf Course - The Arroyo Seco Golf Course in South Pasadena.
San Rafael - The creek coming from Johnson Lake in Pasadena entering the Arroyo a bit north of the South Pasadena city line.
Restoration (BFI) - The low flow streams in Pasadena's Lower Arroyo.
Seco Street - The storm drain system which drains much of Northwest Pasadena and enters the Arroyo near Brookside Park just south of the Rose Bowl.
Flint Canyon - The Arroyo tributary which drains La Canada Flintridge and meets the Arroyo just north and to the west of Devil's Gate Dam in Hahamongna.
Altadena Drain - The storm drain outlet from Altadena near the top of the Hahamongna basin.
El Prieto - The canyon near the Forest Services homes above the mouth of the Arroyo and Jet Propulsion Laboratory.