HomeMy WebLinkAboutPA2024-0069_2025.10.17_Final EIR_Appendix C. Surf Lagoon Water Systems NarrativeSnug Harbor Surf Park Project Appendix
City of Newport Beach
Final EIR
Appendix C: Surf Lagoon Water Systems
Narrative
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Wavegarden Surf Farm – Newport Beach, CA – Surf Lagoon Water Systems Narrative July 18, 2025
General Description:
The proposed Surf Farm surf lagoon project will utilize proprietary Wavegarden wave generation technology to
create surfable waves within a large manmade body of water. This will be a purpose-built facility, dedicated to
the activity of surfing. The configuration of the lagoon, including the plan layout, water depth profile, perimeter
design, and water circulation and treatment systems are critical to the operation of the lagoon and wave
generation characteristics. The overall lagoon water surface area will be approximately 220,427 SF (5.06 ac)
and the total lagoon water volume will be approximately 10,200,000 gallons (38,600 m3).
The Wavegarden Cove wave basin design for this project will include two separate lagoon areas each
operating as independent bodies of water with dedicated recirculation and water treatment systems. Each
of the two lagoon areas (left and right side) will be equivalent in design and operation. Each lagoon area
will have a water surface of 110,213.5 SF and contain a total of approximately 5,100,000 gallons (19,300
m3) of water, continuously circulated, filtered, chemically treated, and monitored for water quality.
The lagoon water quality will be continuously monitored via an automated water chemistry control system,
maintaining the following water quality parameters at all times during facility operation:
• Water clarity/turbidity: < 5 NTU
• Oxidation Reduction Potential (ORP): minimum 650 mV - maximum 850 mV
• Sanitizer Residual: minimum 0.5 ppm FAC
• pH level: 7.0 to 7.6
Filling of the Lagoon:
The primary water source for initial filling of the lagoon will be the City of Newport Beach domestic water
supply. The peak water demand and associated service size/capacity is to be determined based on desired fill
time of the lagoon. In considering such a large lagoon water volume of 10.2 million gallons, it is possible that a
supplemental water supply may be necessary or desirable to increase the flow rate for initial filling of the
lagoon. Fill rate may be supplemented by use of a fire hydrant to increase water flow available for initial filling.
Filling schedule (date/duration) would likely require coordination with OCWD. Below is a chart indicating
required water service flow rate based on a total fill time ranging from 18 days at approximately 400 GPM, to 2
days at approximately 3,500 GPM.
Initial Fill Rate Study:
Lagoon Volume (gallons): 10,200,000
Fill time (days)18 14 10 8 6 4 3 2
Fill time (hours) 432 336 240 192 144 96 72 48
Avg. water elev. rise (in/hr) 0.17 0.22 0.31 0.39 0.52 0.77 1.03 1.55
Fill rate (gallons/min)394 506 708 885 1,181 1,771 2,361 3,542
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Make-up Water:
Make-up water will be required to maintain an appropriate water level in the lagoon as water is consumed
during normal operation. Water consumption will be due primarily to evaporation and wastewater expelled
during periodic filtration system cleaning cycles. There will also be some water volume lost to waste due to
water carried out of the lagoon when surfers exit, as well as “splash out” from wave action terminating at the
shore of the lagoon. The latter is somewhat undefined at this point in the design process as this will be
influenced by configuration of the lagoon shoreline, drainage systems, wave type and duration of wave
generation during general operation. Each of these factors will also vary dependent on number of users,
weather patterns and environmental conditions. A very rough estimation for average water consumption by the
lagoon systems is as follows:
Evaporation: Approximately 37,700 gallons per day (annual average)
Splash Out: Approximately 30,800 gallons per day (depending on use)
Filter Wastewater: Approximately 10,570 gallons per cycle (cycle duration varies)
Based on these criteria, it is estimated that make-up water service supplying a flow rate of 95 GPM will be
adequate to maintain water level in the lagoon during normal operating conditions. Water level in the lagoon
will be continuously monitored and make-up water introduced via an automated water level control system.
When lagoon water level drops below setpoint the autofill valve will open and run as needed to make up the
required water volume. The flow rate calculation is based on replenishing the anticipated water loss over a 12-
hour period.
Lagoon Water Treatment:
Water balance and sanitation of the lagoon water volume will be maintained via automated water chemistry
monitoring and control systems. The lagoon water characteristics will be similar to that of a traditional
swimming pool in terms of water balance, water clarity, and sanitation. Sodium Hypochlorite will be utilized as
the primary sanitizer and is one of the most common chemical compounds used to maintain a chlorine residual
in traditional swimming pool facilities. Muriatic acid will be utilized for pH maintenance. Both chemicals will be
dosed to the lagoon water through automated feeders in order to maintain a free available chlorine (FAC)
residual of minimum 0.5 ppm, an oxidation reduction potential (ORP) of minimum 600 mV, and a pH in the
range of 7.0 to 7.6. Water clarity/turbidity will be maintained below 5 NTU with aid of the filtration technology
described below. Balanced swimming pool water is generally considered safe to discharge to the storm sewer
system once the pool volume has been dechlorinated to a residual of zero.
An ultraviolet (UV) light system will be utilized as supplemental sanitation of the lagoon water. This system will
be designed to treat 100% of the recirculation flow rate of the lagoon filtration system and will serve to
inactivate chlorine resistant pathogens such as cryptosporidium.
Lagoon Water Filtration:
The lagoon water volume will be continuously filtered utilizing a proprietary state-of-the-art perlite regenerative
media filtration system capable of capturing particulate and removing contaminants from the lagoon water
down to the 1-5 micron range. Perlite filter media has been tested to be 99% effective at removing pathogens
such as cryptosporidium from the filtered water and therefore serves as an additional method of sanitation for
the lagoon water volume. Perlite filter media is derived from naturally occurring volcanic rock, is non-toxic and
environmentally friendly.
The proposed recirculation rate of the filtration system is 8,800 GPM resulting in approximately a 19.3-hour
turnover rate for the 10,200,000-gallon lagoon volume. The perlite filter media will need to be changed
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periodically. Filter cycle duration will vary with user loading, weather, and other environmental factors. It is
anticipated that the filter cleaning procedure will take place on average once every two weeks, but filter cycle
durations may be extended based on the factors mentioned above. When the filter media is changed, the
process will drain approximately 2,650 gallons of wastewater to the sanitary sewer system per filter (four filters
total). This wastewater volume will contain the spent perlite media. Filter backwash wastewater will be
discharged through an air gap to the sanitary sewer system managed by Costa Mesa Sanitation District. Local
utility elevation and capacity will be studied to determine the most suitable method of conveying filter
wastewater to the sewer system. Most jurisdictions will allow spent perlite media to be discharged into the
sanitary sewer system, but in some cases the spent perlite media must be strained out and disposed of
separately. Approximately 520 lbs of perlite media will be discharged with the wastewater flow for each filter
per backwash cycle.
Lagoon Maintenance Drainage:
There will be limited occasions when the lagoon may need to be partially or completely drained for
maintenance or for operations related reasons, such as a storm event introducing additional water volume to
the system. In a worst-case scenario when the entire lagoon would need to drained for repairs or
maintenance, the 10,200,000 gallon water volume would first be dechlorinated by dosing sodium thiosulfate
prior to pumping the water out to the storm sewer system. Approximately 575 lbs of sodium thiosulfate would
be required to dechlorinate the entire lagoon volume to a zero-chlorine residual. Granular sodium thiosulfate
can be dosed to the lagoon by hand or mixed as a slurry and fed via metering pump. The drain pump rate is to
be determined and would be dictated by the storm sewer or detention system capacity which will receive the
dechlorinated lagoon water. Dechlorinated lagoon water would be pumped to drain at an appropriate rate and
the timing of this would be coordinated by operations staff according to local utility requirements. Drain rates
and duration would be equivalent to the fill rate summary included above.
In the case of a storm event introducing additional water volume to the lagoon, the lagoon wave generation
systems can remain operational with a water level fluctuation up to 2-inches. Wavegarden proprietary water
management systems include meteorological monitoring to automatically restrict autofilling of the lagoon in
anticipation of heavy rainfall. For example, if we assume there is a torrential rain event expected for the
coming Friday, on Monday the system will automatically begin restricting autofill water introduction to the
lagoon, and by close of operations on Thursday the water level in the lagoon will have been reduced in
anticipation of the pending rainfall event. This system reduces the likelihood of water needing to be discharged
to waste due to a storm event. However, if there is a very large or unexpected rain event, a water level rise in
the lagoon greater than 2” would require water to be discharged to waste prior to restarting surfing operations.
That said, the lagoon basin is capable of receiving up to 11.8 inches of rainwater above normal operating level
before overflowing, so in the event of a major storm, the lagoon can hold a significant volume of water while
operations are paused allowing storm surge to dissipate prior to draining lagoon water and restarting surfing
operations. Any excess water would be pumped to drain at an appropriate rate and the timing of this would be
coordinated by operations staff according to local utility requirements. Prior to discharge the lagoon water
would be allowed to dechlorinate through natural dissipation during days of non-use, or alternatively sodium
thiosulfate could be dosed in the pipe flow or holding tank as the water is discharged. For every inch of excess
water elevation contained in the lagoon, the equivalent volume is approximately 137,409 gallons.
End of Surf Lagoon Water Systems Narrative