Tuesday, November 22, 2011

Why is the ocean brown?

Every time it rains, runoff from the land impacts the river and coast.  And although we have accepted the 'chocolate milk' surf as normal after it rains, it has not always been this way.  This is what is known as a 'Shifting Baseline.'  (See Shifting Baselines in the Surf)

Rainfall this weekend was equivalent to what is known as the 'design storm' - we received approximately one inch over a 12 hour period.  For regulatory and engineering purposes, this quantity of rainfall can and should be retained on site.  This requirement is in the Ventura Countywide 'MS4'  (Municipal Separate Storm Sewer System) Permit, as a standard that all new development will be held to.

The problem, however, is that over the past 100 years our development patterns have directed rainfall off the land, into storm drains, and directly into the river and ocean.


Here's what Ventura Avenue looked like during the rain: the parking shoulder was flowing like a creek.  This is an example of Urban Runoff, and the water here is carrying everything from 'dog poop' and trash, to brake fluid and pesticides, into the storm drains and out to sea.


A little further up the Avenue are the oil fields.  Here the runoff changes to a muddy brown.  Here erosion of soil from miles of oilfield roads in the hills and large impervious work yards flushes into the street...

...into the storm drains, and out to the ocean.  Any chemicals that have spilled or absorbed into the ground are flushed off the land along with this soil.

Santa Barbara ChannelKeeper Stream Team volunteers have been sampling this site for a couple of years, and although oil and gas is generally exempt from clean water rules, Santa Barbara ChannelKeeper has been successful in forcing Aera Energy to enroll in the industrial stormwater permit program.  

This video, starting around 3:20, describes ChannelKeeper's work and illustrates the runoff from this area, and also shows how security guards harass watchdogs, even though this is a public street.  


As the video illustrates, another major source of pollution agriculture.  Both livestock and irrigated crops contribute to water quality problems.  

One area we have been watching is the recent expansion of orchards and row crops at Taylor Ranch on the west side of the Ventura River.  This strawberry field was sprayed with chemicals on Friday, despite the storm bearing down on the region.  Because conventional strawberry growers use plastic to cover the ground, these fields generate significant runoff when it rains. 

Here a Santa Barbara ChannelKeeper volunteer is collecting a water sample from under the Main St bridge, just downstream of these fields.    Note the color of the river water. This sample will be analyzed for pesticides...  although a full-suite analysis would likely turn up a variety of pollutants.

Under the bridge is one of dozens of campsites in the floodplain - another issue of concern documented here: Salmon Run focuses on trash issue

We also went to look at the runoff onto Emma Wood State Beach from the strawberry fields up on the hill at Taylor Ranch.  This is a problem we first documented in 2007  when the fields were first developed.  We continue to received numerous reports from beach users, and this photo confirms that runoff still directly enters the ocean from these fields every time it rains.

The combination of all these sources, known as 'Non-Point Source Pollution' has a significant impact on our coastal water quality and health of the ecosystem.  The fine sediments that enter the river and ocean linger for months, and this is why the water at Surfers' Point often appears muddy, long after the rains have stopped.

This diagram summarizes the issues outlined here.  This is just a small part of the big picture...