Tuesday, October 21, 2008

Agricultural discharges along the lower Ventura River

Last year local beach users documented extreme impacts from new agriculture on Taylor Ranch, above the beach at Emma Wood State Beach. Irrigation of the new plantings resulted in runoff from the impervious plastic sheeting commonly used with industrial strawberries.

This year we are seeing a repeat. Here's a photo of the Ventura River taken from the Main St Bridge on Friday Oct 17.

Here's a report from Santa Barbara ChannelKeeper:

Surfers and concerned citizens have been expressing alarm about unusually muddy water flowing down the lower Ventura River into the ocean, and Stream Team volunteers have been working to identify the source. Over the last two months, we've recorded unusually high turbidity (water clarity) at our sampling site under the Main Street bridge, including the highest dry weather turbidity measurement we've had in eight years of sampling. Upstream measurements at our sampling site near Stanley drain have been normal, indicating that the source of turbidity is somewhere in between these two sites. The biggest recent change to adjacent land use has been the expansion of agricultural operations along the western bank of the lower river.

Recently, a small crew of dedicated Stream Team volunteers helped us investigate the lower river, and found that the river bed is choked with fine sediment. A small drainage ditch has been cut into the western stream bank by irrigation runoff from adjacent agricultural operations. This ditch carries so much sediment into the river, estuary, and ocean that it has significantly increased turbidity. Of additional concern is the potential for agricultural pesticides and fertilizers to contaminate downstream waters.

Agricultural operations are regulated by the State's Porter Cologne Water Quality Control Act under the Conditional Waiver of Waste Discharge Requirements for Discharges from Irrigated Lands. They are required to have in place a water quality monitoring program, a Water Quality Management Plan, and Best Management Practices (BMPs) that ensure they are not significantly impacting downstream water quality. Channelkeeper has written a letter to the Los Angeles Regional Water Quality Control Board requesting they inspect adjacent agricultural operations to ensure that these measures are being implemented, and our volunteers have approached the City of Ventura with these same concerns. City staff have already contacted the facility to discuss irrigation runoff issues and future BMP improvements. Channelkeeper and Stream Team will continue to monitor conditions along the lower river.