Updates from Cowell Beach - November 2014

1. Coe
Cowell Beach Update
November 2014

2. What Storm Water Drains To
Cowell Beach?
Site Overview
Storm water drains to
Cowell Beach (except
during dry season
diversion) from:
Neary Lagoon
Laurel Creek
(thru Neary)
Bay Creek
(thru Neary)
Storm drain inlets
between Neary
Lagoon and Cowell’s
Beach

3. Beach Bummer List‐Why Now?
• The new sampling
location, called “Cowell
Beach West of Wharf,” has
made Heal the Bay’s Top
10 Beach Bummer List the
last 4 years.
• The other main Cowell
Beach sampling point, “At
the Lifeguard Station,” also
has similar diminished
water quality but has
never been on the Beach
Bummer list.
In 2010 the County permanently added a sampling point in front of
the Neary Lagoon beach outlet vault due to increasing bacteria
levels in 2008 at the regular Cowell Beach sampling point.

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County Environmental Health Services:
Cowell Beach Monitoring
County EHS Beach
Monitoring Locations
• Collects water
quality samples
along Cowell &
Main Beaches
• Sampling done at
least weekly all
year round, and
more frequently
during summer
• Cowell Beach, West
of Wharf, is
sampling pt. #0488

5. County Environmental Health:
• Conducts sampling at least
weekly all year round, and more
frequently during summer
• Cowell Beach “West of the
Wharf” posted due to high
bacteria levels
• Cowell Beach “At the Lifeguard
Station” often has elevated
bacteria levels in summer
• Cowell Beach “At the Stairs”
typically very clean
Cowell Beach Monitoring

6. City also monitors weekly for bacteria (since 2010):
• 3 Cowell Beach locations
• 1 Main Beach location
• 1 San Lorenzo River mouth station
Cowell Beach Monitoring

7. The Cowell Beach Puzzle
Unanswered Questions:
• Why does the area near the beach outlet vault (West of
the Wharf) typically have the highest bacteria levels?
• Why are bacteria levels much higher in summer?
• Data can vary wildly. Why?
• Have we found all controllable & human sources of
bacteria?
• When and how much benefit will we see from isolating
Neary Lagoon from Cowell Beach during the summer?

8. • City results also show
very low bacteria
during winter months
• Major sewer source
unlikely as levels would
be high year round
• In 2014, City added
caffeine test as possible
tracer for domestic
sewage: NONE found
so far
Cowell Beach Monitoring
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12/1/2013 1/30/2014 3/31/2014 5/30/2014 7/29/2014
5 sample Geometric Mean (CFU/100mL)
FECAL COLIFORMS
Geo. Mean Limit Fecal
ENTEROCOCCUS
Geo. Mean Limit Enterococcus
Geometric Mean (5 sample) Bacteria Levels at
Cowells Beach West
December 2013‐July 15, 2014
So, what’s the difference between winter & summer?

9. Cowell Beach‐Potential Factors
What’s different in summer?
More
• People using the beach
• Birds on the Wharf
• Sea lions on the Wharf
• Pigeons below the Wharf
• Seabirds, sometimes thousands, near‐shore
following fish bait balls
• Upwelling in Bay: small fish, squid, jellyfish, krill
• Trash on the beach

10. Cowell Beach‐Potential Factors
What’s different in summer?
Also:
• Neary storm drain lines tend to stagnate w/high
bacterial growth (improvements in progress)
• River tends to be shoaled: winter flows may improve
circulation & reduce pressure on groundwater
• Less wave action & storms
• Higher air & sand temperatures
• Off‐shore current changes

11. County of Santa Cruz
• Kelp may be a source of concern as rotting kelp can cause
amplification of bacterial concentrations at Cowell Beach
(kelp can serve as a substrate for bacteria).
• EHS has documented the potential for bacterial regrowth
in decaying kelp. EHS findings supported by a San Diego
study, by Weston Solutions, at a popular surfing beach
which also came to this conclusion.
• Due to abundant offshore kelp beds, kelp continually
washes up at Cowell Beach in spite of beach grooming
efforts. Thus, there is residual bacteria in the water for at
least several tidal cycles unless there is a significant
swell/wave action.
Environmental Health Services‐ Kelp Findings

12. What has the City Done
• Found an offset residential
bathroom sewer line joint.
Sanitary waste discharged into
rock wall along Pacific Ave., near
2nd St., flowing to street draining
to Cowell Beach.
• Promptly fixed in August 2013.
Sewer Lateral Investigation
A significant sanitary
waste source found &
eliminated

13. What has the City Done
In 2013, cap placed on a storm drain grate inlet, near RR
tracks under trestle bridge, inlet had been used as an
outdoor bathroom.
Inlet flows into Neary Lagoon drainage lines exiting at
Cowell Beach.
Area now patrolled regularly.
A sanitary waste source
found & eliminated

14. Neary Lagoon: Dry Season Diversion to
Wastewater Treatment Facility
• Summer diversion: 300,000‐
500,000 gallons per day
• Lagoon water is treated and
discharged via the plant’s
effluent pipeline to the Pacific
Ocean 1‐mile offshore Diversion since 1994

15. Neary Storm Summer Conditions
Even with diversion, some
water remains in the large
Neary storm drain pipes &
stagnates, causing
elevated bacteria levels in
the pipes.
Water can seep out, from
the uncapped pipelines,
under the sand at the
Cowell Beach outlet vault.
Thus, these storm drain
lines are a potential
source of bacteria at
Cowell Beach.

16. Isolating
Neary Lagoon from Cowell Beach
• Installed slide gates to block flow from Neary to
Beach (April 2014)
• Cleaned beach vault (October 2014)
• Cleaned & TV’d two Neary pipelines (October
2014)
• Install pipeline so water remaining between slide
gates and beach can be pumped to Sanitary
Sewer (to be constructed)

17. Neary Outlet at Beach
Inlet to Pump Station
& Neary Lagoon Pipes
Pipes under sand in summer

18. Slide Gates being Installed
Site prep:
dewatering
& cleaning
Culverts
under RR
tracks

19. Slide Gates Completed
April 20, 2014

20. City Increases Investigation Sampling
Neary Lagoon ‐Laurel Creek Upstream Monitoring
Conclusion to Date:
• High bacteria likely from
pets & other non‐human
sources
Results from 11 sets of samples:
• Only one “hit” for caffeine in
June, not detected again
• City continues investigation

21. City Efforts
• Expand monitoring at Cowell Beach and Neary
Lagoon for human DNA and caffeine.
• Monitor Cowell Beach further from shoreline.
• Monitor Cowell Beach more this winter.
• Study potential impacts from sand and kelp.
• Study relationship between bacteria results and
swell.
• Study near‐shore currents.
Further Work

22. Sewer Lateral Inspection Program
• Sewer lateral inspection program planned
for residential & commercial properties
• Lateral inspection required at time of sale
• Anticipated start date: 2016
City Efforts

23. Cowell Beach‐Conclusions
City has eliminated several direct sources of contamination
City has also reduced impacts from Neary Lagoon drainage
system
It may take time to see improved testing results at Cowell Beach
City plans to continue and expand testing at Cowell Beach
Expand public interactions with local community
Presentation by Suzanne Healy and Steve
Wolfman, Dept. of Public Works
Questions or For More Information:
Please call Steve Wolfman:
831‐420‐5428