Periodically, staff from the Ventura County Watershed Protection District perform special studies to address water quality issues.

Matilija Dam Water Quality Monitoring Project
As part of the Army Corps of Engineers Feasibility Study for the removal of Matilija Dam, a $60,000 Grant was awarded to the Ventura County Watershed Protection District (VCWPD) to collect and provide sufficient water quality data to identify the potential impacts to water quality and associated aquatic habitats with the removal of the Matilija Dam. Due to a shortage of rain during the 2003/2004 monitoring season, the VCWPD was granted a one-year extension to allow for the collection of additional wet event water quality data during the 2004/2005 winter season, which extended the grant through December 31, 2005.

The grant provided for the following:
• Installation of two automated water quality stations on Matilija Creek.
• Collection of water quality samples during 8 events (3 dry and 5 wet).
• Analyses of water quality samples for over 200 priority pollutant parameters, including toxicity, bacteria, nutrients, heavy metals, semi-volatiles, PCBs and pesticides

Some results derived from the sampling and analysis effort:
• No detections of organochlorine pesticides, orthophosphate pesticides, chlorinated herbicides, or semi-volatiles.
• No exceedances of water quality standards established by either the California Toxics Rule (CTR) or the Los Angeles Regional Water Quality Control Board’s Basin Plan for the Coastal Watersheds of Los Angeles and Ventura Counties.
• No significant difference between the upstream and downstream sites with respect to most parameters (see next bullet).
• Six detections of BOD and three detections of TKN at the downstream site, which may indicate a potential source of pollution entering the waterway between these two sites.
• Metals, nutrients and indicator bacteria detected much more frequently during wet events.
• Conductivity and chloride elevated during dry sampling events.
• No indication of either acute or chronic toxicity.

The full report is available both here and at the Matilija Dam Ecosystem Restoration Project website. Data from this study can also be found at the Ventura River watershed page on this website.