To: MAYOR AND CITY COUNCIL
From: ELIZABETH HAUSE, WATERFRONT AND COMMUNITY SERVICES DIRECTOR MARC WEINER, COMMUNITY DEVELOPMENT DIRECTOR
TITLE
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DISCUSSION AND POSSIBLE ACTION REGARDING THE SEASIDE LAGOON REHABILITATION PROJECT
APPROVE THE FINAL PREPARATION AND SUBMITTAL OF A COASTAL DEVELOPMENT PERMIT APPLICATION TO THE CALIFORNIA COASTAL COMMISSION FOR THE SEASIDE LAGOON REHABILITATION PROJECT AT 200 PORTOFINO WAY
APPROVE THE ENVIRONMENTAL EXEMPTION DECLARATION FOR THE PROJECT
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EXECUTIVE SUMMARY
The City is proposing the rehabilitation and modernization of Seaside Lagoon to replace aging infrastructure, address current water quality and public health requirements, and maintain the facility's longstanding function as a low-cost public waterfront recreational amenity. Following extensive community outreach, engineering and cost analysis, and regulatory review, in April 2026 the City Council directed staff to proceed with a project scope that can be delivered within available funding while maintaining the project's primary recreational and Measure C objectives.
The proposed project includes a new five-foot-deep recirculating recreational lagoon with beach areas, sand entry and water play features, a new mechanical building with contemporary water filtration and pump equipment, a new restroom facility, upgraded utilities and infrastructure, ADA-accessibility improvements, enhanced fencing, new shade structures, landscaping, and other site improvements.
The lagoon is within the CA Coastal Commission’s jurisdiction and requires approval of a coastal development permit (CDP). In order to complete construction of the Seaside Lagoon Rehabilitation Project prior to the start of the 2028 Summer Olympic Games, the CDP must be approved in early 2027.
On August 25, 2026, the Harbor Commission held a special meeting to review the project scope and environmental determination and received public testimony. As discussed in greater detail below, the Harbor Commission voted to find that the project design, as presented, is consistent with the applicable CEQA exemption determinations. Separately the commission voted to recommend the City Council not proceed with the current project design. The Commission instead recommended the City Council 1) pursue the design initially approved in 2024, which included greater water depth, a sand bottom, saltwater, and year-round activation amenities; 2) accommodate State guidelines for 2050 sea level rise; and 3) seek an extension of the related State grant.
Staff recommends advancing the project scope (as designed and discussed in April 2026) and submitting the corresponding CDP application to the California Coastal Commission. Following submission of the CDP application, staff will work with Commission personnel to address any public access, water quality, hazard, or sea level rise considerations/modifications that arise during the entitlement review. Any refinements to the project requested by the Commission will be presented to the City Council for final confirmation.
BACKGROUND
Seaside Lagoon is a City-owned recreational facility located within King Harbor at 200 Portofino Way within the Parks, Recreation, and Open Space (P-PRO) zone in the coastal zone. Constructed in 1962, Seaside Lagoon has served the residents of Redondo Beach, the greater Los Angeles area, and visitors from throughout California. Seaside Lagoon is open to the public between the Friday of Memorial Day weekend and Labor Day every year. For the 2026 summer season, the Lagoon received over 50,219 visitors, and over 100 reservations for camp and summer program activities.
The facility consists of a man-made, tidally-influenced saltwater swimming lagoon, sandy beach areas, picnic facilities, playgrounds, restroom facilities, and other visitor-serving recreational amenities. The Seaside Lagoon has operated seasonally as a public swimming facility for decades and is a long-standing defining feature of King Harbor. The facility's original infrastructure including its seawater intake, discharge, and chemical treatment systems have reached the end of their useful life. Continued maintenance of these structures has become increasingly difficult and costly. The systems do not allow for modern water circulation and filtration and rely on the intake and discharge of millions of gallons of ocean water each day. The antiquated systems predate modern water quality discharge requirements and frequently expose the City to violations and fines that are administered by the Los Angeles Regional Water Quality Control Board (Regional Board). Accordingly, the City has been evaluating and seeking funding for long-term site rehabilitation alternatives for the Seaside Lagoon for nearly two decades. The most recent planning and community outreach efforts for reconstruction of the Lagoon are outlined below.
2021-2022: Waterfront Public Amenities Planning and Community Outreach
The City began planning for the rehabilitation of Seaside Lagoon in 2021 as part of the King Harbor Public Amenities Plan, with extensive community engagement including pop-ups, community meetings and online surveys. Outreach continued through 2022 and included multiple public meetings and events, with hundreds of residents and stakeholders participating in the feedback process. These outreach efforts considered a range of potential aquatic amenities and improvements to Seaside Lagoon.
2022-2023: Transition to Seaside Lagoon Project Design
Following the broader waterfront amenities planning process, the City moved into the design and engineering phase for the Seaside Lagoon project. The City Council approved the Lagoon’s design RFP in May 2022, received three qualified proposals, and selected NUVIS to lead the design, engineering, environmental review and entitlement process. The City and NUVIS then began project-specific community engagement and design development in 2023.
2023-2024: Project-Specific Community Outreach
The City continued public engagement as the Lagoon design developed, including pop-up events, stakeholder meetings and Harbor Commission subcommittee meetings. A December 2023 community workshop specifically explored potential year-round amenities, including lap swimming and various wave-oriented concepts. This outreach informed the development of multiple conceptual design alternatives and refinement of the preferred project scope.
2024-2025: Harbor Commission and Council Review
The Harbor Commission considered the Seaside Lagoon project on September 9, 2024. At the meeting, the Commission discussed the various design options, including the style and orientation of new potential restroom, locker, office and cabana buildings, the configuration of a new promenade, alternative water sources, and the possibility and cost of a wave making feature. The Commission ultimately voted 7-0 to recommend that the City Council pursue a complete renovation of Seaside Lagoon using a phased approach, with Building Placement Option 2 and Promenade Design Option 2.
The Commission’s recommendation was for a complete, multi-phased renovation, recognizing that the City would need to construct the project in phases as funding became available. The September 2024 staff report estimated the cost to construct the selected design at approximately $31.1 million, while Phase 1 was estimated at approximately $7.0 million. The concept contemplated obtaining entitlements for the entire project while using the funding available at the time to construct Phase 1.
On October 15, 2024, the City Council reviewed multiple conceptual alternatives, and, in alignment with the Harbor Commission’s recommendation, directed staff to continue development of “Design Option 2”, which envisioned a combined recreational lagoon and lap swimming facility integrated within a single water feature together with associated recreational amenities, and a two-story building to hold administrative and lifeguard offices.
The direction provided by Council in 2024 was not based on a construction-ready design. It was direction to proceed with the selected design concept, pursue entitlements, and to begin developing more refined project plans and specifications and associated construction cost estimates. That distinction is important because many of the issues that ultimately changed the project scope could not be fully evaluated until the design was developed further and more specific feedback from staff at the applicable regulatory agencies was provided.
2025-2026: Refined Project Engineering and Regulatory Review
As engineering and budget assessments advanced, several factors required modification of the original concept:
• Coordination with the Los Angeles County Department of Public Health determined that the lap pool and recreational lagoon could not operate as the combined water feature contemplated in the 2024 concept. The two uses would need to be physically separated, with significant decking setbacks and fencing between them. Incorporating the health department requirements into the project design substantially increased the cost of providing both a separate lap pool and recreational lagoon. By 2026, the estimated cost for the updated Phase 1 configuration exceeded $16 million.
• Additionally, geotechnical investigations identified a high groundwater table that limited the feasibility of excavating the lagoon to its current and desired depth. The design team determined that excavation beyond approximately 3.5 feet of depth, would encounter significant groundwater and result in substantial dewatering requirements and associated construction costs. The cost and variability of dewatering was one of the critical reasons for ultimately refining the project scope. The potential need to construct and install a sheet-pile system was also a major concern.
At the time these engineering determinations were made, the City had approximately $7.9 million remaining in the project account and it was clear the lagoon could not be constructed at its current depth nor include a separate lap pool within budget. As such, staff and NUVIS revisited the design and identified what could realistically be built using the available funds.
April 2026: City Council Direction
On April 21, 2026, the City Council considered the updated project scope, construction cost estimates, and level of available funding for the Seaside Lagoon Rehabilitation Project. Following discussion, the City Council directed staff to proceed with a reduced project scope that was within available funding and achieved the project's principal objectives, including modernization of the Lagoon's aging infrastructure, compliance with current water quality and public health standards, consistency with Measure C, and completion of construction prior to the 2028 Olympic Games. The Council also discussed identifying additional funds (and later appropriated QUIMBY monies) to support building the lagoon to a depth of five feet (by increasing the decking height), include a prefabricated restroom with two unisex stalls in the project, upgrade the facility’s perimeter fencing with an eight-foot-tall tube steel fence, and to include a sand entry in and around the lagoon’s water feature.
August 2026: Harbor Commission Special Meeting
The Harbor Commission held a special meeting on August 25, 2026, to review the Seaside Lagoon Rehabilitation Project. City staff and the City's consultants presented the project history, existing site conditions and constraints, and the updated design elements following Council's April discussion, including the revised lagoon depth, new pump and filtration building, restroom facility, perimeter fencing, and related site improvements.
Following the discussion, the Harbor Commission voted 7-0 to find that the project design, as presented, was consistent with the applicable California Environmental Quality Act (CEQA) exemption determinations. The Commission separately voted 7-0 to recommend the City Council not proceed with the design as presented.
Instead, the Harbor Commission recommended the City continue to pursue the design initially approved in 2024, including greater water depth, a sand-bottom lagoon, saltwater, and year-round activation amenities. The Commission also recommended the Project accommodate the State's 2050 sea level rise guidelines and the City Council seek an extension of the related State grant.
Project Design
The proposed project replaces the aging seawater lagoon and supporting infrastructure with a modern recreational swimming lagoon that complies with current public health, safety, accessibility, and water quality standards. The project is designed to improve the year-round functionality of the site, while maintaining expansive public open space and creating flexible areas capable of accommodating passive recreation, community gatherings, and special events.
The architecture and site design were developed to enhance the waterfront recreational facility with high-quality public spaces through the integration of recreational amenities, landscaping, and architecturally compatible buildings. The proposed improvements maintain the open character of the site, strengthen connections to the Harbor waterfront, and enhance accessibility throughout the facility through new pedestrian pathways, plazas, and gathering areas.
The existing seawater lagoon would be replaced with a new recirculating recreational lagoon utilizing a closed-loop filtration and treatment system. The lagoon is designed with a walk-in sand beach entry along the northern shoreline that gradually transitions into a deeper swimming area on the harbor side with a maximum water depth of five feet and a plaster-finished bottom. A submerged dividing wall separates the shallow sand-bottom recreation area from the deeper swimming area with a line of buoys located above the dividing wall to clearly identify the transition for users. Sand beaches surrounding the majority of the lagoon are included to create a natural beach environment while maintaining a defined swimming area. The project also includes new water play features, improved pathway circulation around the lagoon perimeter, enhanced landscape and hardscape, and expanded opportunities for recreational use.
Figure 1: Lagoon Cross-Section
In addition to the lagoon improvements, the project includes construction of a new 2,660-square-foot, approximately 18.5-foot-tall pump station and equipment building to house the mechanical, filtration, and water treatment systems required to operate the recirculating lagoon. A new two-sided restroom building is also proposed to serve both Seaside Lagoon patrons and visitors utilizing the adjacent Harbor waterfront promenade and public boat launch. The architectural design of these buildings incorporates articulated façades with white painted brick, standing seam metal roofs, coordinated exterior materials that will complement the existing structure, and architectural detailing that complement the surrounding Harbor environment while maintaining a low-profile scale appropriate for the waterfront setting. Supporting infrastructure improvements include new utilities, drainage facilities, grading, lighting, electrical improvements, and other infrastructure necessary for the long-term operation of the facility.
The project substantially enhances the lagoon adjacent recreational facilities through the addition of ADA-accessible pedestrian pathways, ADA-compliant ramping into the Lagoon water, plaza areas, a 12-foot-tall luau shade shelter, picnic and barbecue facilities, seating areas, decorative paving, improved perimeter fencing, and removable partition fencing that allows the water area to be separated and secured when not in operation, and allowing public access to the surrounding sand areas adjacent to the waterfront. Extensive landscape improvements include new trees, shrubs, irrigation, and natural grass areas to enhance the visual quality of the site, and provide additional shade.
Figure 2 - Seaside Lagoon Fencing
Implementation of the project requires demolition and replacement of portions of the existing lagoon infrastructure, including removal of the existing lagoon basin, mechanical equipment, additional restroom facilities, fencing, hardscape improvements, selected landscaping, and associated site improvements. Existing sand will be relocated and reused where feasible, mature palm trees will be preserved or relocated where practical, and new landscaping will be installed throughout the project area. The project has been designed to minimize impacts to existing recreational facilities while preserving significant landscape features wherever feasible.
Overall, the proposed improvements will transform Seaside Lagoon into a modern, year-round waterfront recreational destination while preserving its role as a public swimming and beach recreation facility. As depicted in the project plans and architectural renderings, the project combines contemporary coastal architecture, high-quality landscape design, enhanced public amenities, environmentally compliant and sustainable operational systems, and upgraded recreational facilities in a cohesive waterfront environment. The project preserves public views toward King Harbor and the Pacific Ocean, maintains human-powered watercraft access to the Harbor, improves accessibility and visitor comfort, and provides modern infrastructure capable of supporting the continued operation of Seaside Lagoon in compliance with current public health, safety, and environmental regulations, and consistent with the City's King Harbor Amenities Plan and Measure C.
Measure C Compliance
The project is designed for consistency with the voter-approved requirements of Measure C, which amended the Public, Recreation and Open Space (P-PRO) regulations applicable to the Seaside Lagoon Regional Park. Measure C requires that if the existing saltwater swimming facility is replaced for water quality purposes, it be replaced with a recreational swimming facility of at least equivalent water surface area that complies with applicable public health, safety, and environmental regulations while preserving the park's primary recreational amenities, including the sandy beach, volleyball courts, picnic and barbecue areas, play equipment, luau shelter, restroom facilities, human-powered watercraft access, and public open space. The proposed project satisfies these requirements by replacing the existing lagoon with a modern recreational swimming facility of equivalent surface area that complies with current public health and water quality standards, preserves the site's recreational function and visitor-serving amenities, maintains public access and open space, and continues Seaside Lagoon's long-standing role as a premier waterfront recreational destination.
Coastal Access
The proposed project maintains and enhances public coastal access by improving pedestrian circulation, accessibility, and visitor-serving amenities without restricting access to the Harbor or waterfront promenade. Improvements include new ADA-accessible pathways, plazas, landscaping, and reconfigurable fencing that allows greater year-round public access to the park and lawn space when the lagoon is not in operation. The project also includes a new two-sided restroom building that will serve both Seaside Lagoon patrons and the general public accessing the waterfront promenade. Staff finds the project improves public coastal access and is consistent with the public access policies of the Coastal Act.
Noise
The project consists of rehabilitation of the existing Seaside Lagoon and replacement of aging infrastructure, including the lagoon, pump building, restroom facilities, shade structures, landscaping, and site improvements. The project does not increase the intensity or capacity of the existing recreational use and is not expected to generate additional long-term operational noise. Construction-related noise will be temporary and subject to applicable City regulations.
Parking
The proposed improvements modernize the existing Seaside Lagoon without expanding its recreational use or increasing visitor capacity. The project does not introduce new commercial uses or development that would increase parking demand. Existing public parking facilities serving King Harbor and Seaside Lagoon will continue to accommodate the project. Staff finds the project will not result in significant parking impacts.
Traffic/Pedestrian Access
The project replaces and upgrades existing recreational facilities without increasing the intensity of use or generating additional vehicle trips. Improvements include ADA-accessible walkways, enhanced pedestrian connections, new plazas, landscaping, and improved circulation throughout the site. These improvements enhance pedestrian safety and accessibility while maintaining existing traffic patterns. Staff finds the project will not result in significant traffic impacts and will improve pedestrian access to Seaside Lagoon, the waterfront promenade, and adjacent Harbor amenities.
Environmental Status
The proposed project is categorically exempt from the California Environmental Quality Act (CEQA) pursuant to CEQA Guidelines Sections 15301 (Existing Facilities) and 15302 (Replacement or Reconstruction). The project consists of the rehabilitation and modernization of the existing Seaside Lagoon through the replacement of aging recreational infrastructure, including the lagoon, pump building, water treatment systems, restroom facilities, utilities, hardscape, and landscaping, while maintaining the existing recreational use and operational capacity of the site. The replacement improvements will serve substantially the same purpose at the same location and do not result in an expansion of the facility or its intensity of use. Staff has also determined that none of the exceptions to the use of a categorical exemption identified in CEQA Guidelines Section 15300.2 apply.
At its August 25, 2026 special meeting, the Harbor Commission considered the CEQA determination as part of its review of the project and voted 7-0 to recommend the Council approve the CEQA Exemption Declaration.
Project Questions
During the August 2026 Special Meeting of the Harbor Commission, questions arose regarding certain elements of the Seaside Lagoon rehabilitation project. Those questions are answered below.
Does the Seaside Lagoon Rehabilitation Project accommodate 2050 Sea Level Rise Guidelines?
The Project is subject to, and will be evaluated for consistency with the California Commission’s 2024 Sea Level Rise Policy Guidance and the California Ocean Protection Council’s 2024 State Sea Level Rise Guidance. Staff have met with Coastal Commission personnel to discuss the Project’s compliance with these Guidelines. The discussions with coastal staff indicate the proposed Seaside Lagoon Project design will comply. It is important to note that the State guidance does not establish a single elevation that projects must meet by 2050. Rather, it provides a range of scenarios and recommends that projects consider location, anticipated service life, potential consequences of flooding or failure, and the ability to adapt over time.
For the Los Angeles tide-gauge area, the guidance projects approximately 0.4 to 1.1 feet of sea level rise by 2050, relative to the year 2000, and approximately 0.6 to 6.3 feet by 2100 depending on the scenario. The guidance therefore emphasizes an adaptive approach for projects with long service lives rather than requiring projects to be constructed initially to accommodate the highest projection in year 2100.
The current sand bottom Seaside Lagoon is excavated to provide roughly 8 feet of water depth when full. The concrete liner of the new Lagoon is expected to be roughly 4 feet higher than the current excavated depth of the facility and include approximately 2 feet of sub material. In 2019 Pace conducted a study that showed the Lagoon maintains approximately 2 feet of tidally influenced water during the offseason. Accordingly, the concrete liner and base for the new lagoon are planned to be built above this elevation. If the mean tide line rises a full foot over the next 25 years, a portion of the sub material will be subjected to periodic ground water. The concrete liner should however remain above the mean high tide line.
The Seaside Lagoon Project does not include an adjustment to the existing seawall or bulkhead, so no specific construction is proposed for those features to accommodate 2050 sea level rise projections. However, it is important to note the Lagoon’s structural design incorporates a pressure-relief system to address elevated groundwater pressures and buoyancy during significant groundwater events, providing added resilience as groundwater conditions change over time. The design also accommodates future adaptation measures that could be constructed should sea level rise become a significant operational concern. These include raising or modifying the bulkhead or coping, improving backflow protection, and relocating or adapting ancillary facilities as conditions warrant.
In short, the project is designed to meet current sea level conditions and accommodate an appropriate initial sea level rise planning horizon, while preserving the ability to implement additional adaptation measures if needed, as sea level rise occurs. The California Coastal Commission will evaluate the Project’s proposed sea level rise strategies as part of the CDP review process.
What will be the impact to the Lagoon during storm surges, and how will the project protect the Lagoon's structural integrity?
The proposed Lagoon is designed to withstand significant storm-related groundwater fluctuations through a pressure-relief system incorporated into the Lagoon structure. This system will allow elevated groundwater pressure beneath the concrete shell to dissipate, reducing upward buoyant forces and protecting the structural integrity of the Lagoon during significant groundwater events.
Storm surge and sea level rise present related but distinct engineering considerations. Sea level rise is a gradual increase in coastal water levels over time, while a major storm can temporarily increase both coastal and groundwater elevations. Because the proposed Lagoon is a below-grade, concrete-lined structure, elevated groundwater beneath the Lagoon can create hydrostatic pressure and upward buoyant forces.
NUVIS evaluated this condition using the project’s geotechnical information and determined that, during a significant groundwater surge, portions of a deeper Lagoon could experience buoyancy forces greater than the self-weight of the concrete bottom. Under the current analysis, areas deeper than approximately 2.33 feet would require additional buoyancy protection.
Three preliminary approaches were evaluated to address this condition:
• Tiedown piles: Mechanically anchor the Lagoon structure to resist upward buoyant forces. NUVIS' preliminary order-of-magnitude cost was approximately $53.89 per square foot.
• Structural concrete system: Construct two 12-inch concrete slabs connected by approximately 18-inch square concrete columns, with the intervening space infilled with concrete to provide additional structural weight. The preliminary order-of-magnitude cost was approximately $113.70 per square foot.
• Pressure-relief system: Use a lighter concrete slab incorporating pressure-relief valves to allow groundwater pressure beneath the Lagoon structure to dissipate during an elevated groundwater condition. This is the option included in the proposed design and has cost of approximately $29.89 per square foot.
Based on current site conditions, geotechnical information, and engineering evaluation, NUVIS is incorporating the pressure-relief approach into the design. The system addresses the identified buoyancy condition by allowing groundwater pressure beneath the Lagoon to dissipate rather than relying solely on additional structural weight or mechanical anchoring. It also provides resilience as groundwater conditions change over the life of the project.
The design team also evaluated permanent subdrainage beneath the Lagoon. Because the Lagoon structure is above the anticipated normal groundwater table, a subdrainage system would primarily operate only during unusual groundwater surges and would require pumps and associated infrastructure that would need to be maintained despite limited normal use. Based on the current groundwater conditions and engineering evaluation, NUVIS does not recommend permanent subdrainage as part of the final design.
Can the Seaside Lagoon be designed as a saltwater amenity, and how would the cost compare with a chlorinated freshwater system?
The Seaside Lagoon could potentially be designed as a saltwater system, but it would be subject to significant regulatory challenges as compared to a fresh water system. In this context, “saltwater” would refer to a conventional saltwater pool system, rather than a system using seawater. A saltwater pool uses water with a relatively low concentration of dissolved salt and an electrolytic chlorine-generation system to produce chlorine for disinfection. The system remains a recirculating pool system and would not have the salinity of ocean water.
Converting the currently proposed chlorinated freshwater recirculating system to a saltwater system is technically feasible, though cost and discharge requirements may create regulatory constraints and operational consequences. Based on preliminary estimates from the design team, a saltwater system would add approximately $150,000 to $200,000 in initial construction costs. Ongoing operating costs are expected to be higher than a traditional chlorine system but would depend on the type of system selected and the amount of required salt, replacement of electrolytic cells, increased equipment maintenance, effectiveness of corrosion-resistant components, additional water-quality monitoring, and other potential maintenance requirements.
The more significant consideration is water discharge for both routine filter backwash and evacuation of pool water in significant volume. The proposed Lagoon is designed as a closed, recirculating system, substantially reducing the need for high volume discharge and eliminating the historical direct discharge to King Harbor. While a saltwater system would also be recirculating, the addition of salt introduces an additional water-quality consideration whenever Lagoon water must be discharged.
Discharge of salt water from the lagoon to the environment (street, storm drain or directly to the harbor) is in violation of the City’s Municipal Code and strictly prohibited by State Law without a discharge permit from the Regional Board, which is in contradiction to project goals to no longer be obligated by such a permit.
The new system must be designed to discharge to the City’s sewer collection system. Discharge to the City’s sewer system is regulated by the City and by the Sanitation District of Los Angeles County, the agency that manages municipal sewage transmission, treatment, and eventual ocean discharge for much of the county.
The City has not yet quantitatively evaluated impacts of salt water brine from both the lagoon and filter backwash water to its sewage infrastructure, primarily the Portofino Pump Station located just outside of the entrance to the facility. Salt water, in anticipated concentrations, is markedly more corrosive than fresh (chlorinated) water and would likely reduce the life span (and therefore reliability) of Portofino Pump Station’s mechanical and electrical components. The pump station was just rebuilt, but not with regular concentrations of saltwater in mind. More work is needed to quantify the impacts of a salt water system on City infrastructure, especially the Portofino Pump Station, but qualitatively staff anticipates increased expense in maintenance and operations of the sewer system under a salt water scenario.
The Sanitation District must operate under its NPDES discharge permit, which is also regulated by the Regional Board. Under current Los Angeles Regional Water Quality Control Board requirements of that permit, dechlorinated swimming-pool water may be discharged through the municipal storm drain system when specified water-quality and best-management-practice requirements are satisfied. These requirements address chlorine, pH, pollutants, and total dissolved solids, including salts. In addition to these discharge parameters, pool water from systems commonly referred to as “saltwater pools” may not contain salt concentrations that exceed applicable water-quality objectives. Large-volume discharges are also subject to additional discharge-management and notification requirements.
These parameters should be considered a minimum standard from the Sanitation District, but more specific standards may apply. For instance, the County’s Public Works Department, where it serves as the authority having jurisdiction over the sewer collection system, does not allow discharge of saltwater from pools to the sewer system and significantly controls the manner and requirements of discharge of fresh water from pool facilities. Although the County Public Works Department is a legally sperate agency than the Sanitation District, these agencies share employees, and therefore concerns and have adopted a strict “no” policy when it comes to discharge of salt water to the sewer system. More work needs to be done as design develops to understand specific application of Sanitation District standards and regulatory constraints to this project, but it will not likely result in an operationally simple or economical advantage for the City.
The restrictions to be imposed by the Sanitation District will result in an important operational distinction between the two systems. With the proposed freshwater system, the City would manage the water-quality requirements associated with a conventional chlorinated recirculating pool. A saltwater system would add salt concentration as another parameter that must be monitored and managed before water could be discharged. This could become particularly significant when the Lagoon needs to be partially or fully drained for major maintenance, repairs, or other circumstances requiring the removal of a substantial volume of water. The City would need to confirm that the salt concentration of the discharged water complies with applicable water-quality requirements or constraints and identify an alternative approved method of disposal if needed (e.g. tanker truck).
The discharge issue is particularly relevant given the City's experience with the existing Lagoon's historic flow-through system and its associated NPDES requirements. One of the objectives of the proposed rehabilitation is to move away from that direct-discharge model and establish a more manageable, closed recirculating system. Introducing salt into the new system would not recreate the historical system, but it would reintroduce an additional water-quality consideration and uncertainty that the freshwater system avoids.
For these reasons, while a saltwater system is possible, the currently proposed freshwater recirculating system provides a more straightforward approach from a regulatory and long-term operational perspective. The estimated $150,000 to $200,000 initial construction premium for a saltwater system is just the initial cost. Lifecycle cost increases would also need to be considered together with the additional water-quality monitoring, discharge management, and operational considerations associated with managing salt in the Lagoon water.
What is the ongoing operational cost associated with the new Seaside Lagoon design, and how does it compare with current costs?
The new Lagoon, as proposed, is expected to have a positive net annual impact on the City’s Tidelands Fund as compared to the current facility.
The Lagoon is not expected to materially change the daily staffing model. Lifeguard, cashier, guest-service, and similar seasonal staffing requirements are expected to remain generally comparable to the current operation. Staff is, however, evaluating the possibility of extending the operating season beyond the current Memorial Day through Labor Day schedule to capture additional warm-weather demand. An extended season would increase staffing costs, with a portion potentially offset by additional admissions revenue.
Some maintenance activities will change as a result of the new lagoon configuration and treatment system. The proposed Lagoon would operate as a recirculating system rather than the existing flow-through seawater system. Water would be filtered, chemically treated, and returned to the Lagoon rather than continuously drawn from and discharged to King Harbor. This change is expected to substantially reduce the City's regulatory burden and costs associated with the existing direct discharge. The current operation requires approximately $50,000 annually for water-quality monitoring and testing under the City's NPDES requirements and has resulted in more than $935,000 in historical penalties associated with discharge exceedances.
The recirculating system will, however, introduce other types operating costs. These include potable water for the initial fill and replacement of evaporation and splash-out losses; electricity for pumps and filtration equipment; chemicals; filter maintenance; periodic cleaning; occasional sewer discharge fees; and routine removal of accumulated sand and debris. However, the proposed Lagoon will contain substantially less water than the existing facility. The existing Lagoon holds approximately 1.4 million gallons, compared with an estimated 770,000 gallons in the proposed Lagoon - a reduction of approximately 45 percent. Based on an estimate provided by Cal Water, filling the proposed Lagoon once would cost approximately $12,300. Ongoing potable-water consumption would primarily be associated with evaporation, splash-out, maintenance, and other water losses, rather than the continuous seawater intake and discharge required by the existing system.
The difference in water volume is particularly significant when considering the existing flow-through operation. Past Regional Water Board documents indicate that the existing system was designed to receive approximately 3,200 gallons per minute of seawater and discharge approximately 3,200 gallons per minute of dechlorinated water to King Harbor while the Lagoon was in operation. The proposed recirculating system would eliminate this continuous intake and discharge and substantially reduce the volume of water required to fill and maintain the Lagoon.
The new configuration will also require periodic removal of accumulated sand and particulates. Filtration inlets are being designed above the lagoon floor to reduce the amount of sand entering the filtration system. Staff may use commercial in-water pool vacuums or similar equipment to remove accumulated sand and debris. The frequency and cost of this maintenance will depend on actual operating conditions and the amount of sand migrating from the surrounding beach area into the deeper portion of the Lagoon.
The City's annual operating budget provides an existing baseline for Seaside Lagoon operation including personnel, maintenance, chemicals, supplies, and internal service costs. The proposed recirculating system will eliminate or reduce certain existing costs, particularly those associated with continuous seawater circulation, discharge monitoring, and regulatory compliance, while introducing some new costs associated with potable water, filtration and system maintenance.
Staff is continuing to evaluate the anticipated operating costs of the proposed system, including staffing, potable water, electricity, chemicals, filtration and maintenance, water-quality monitoring, regulatory compliance, equipment replacement, and periodic maintenance, but expect the Lagoon’s fiscal bottom line to be improved following construction of the new facility.
Coastal Commission Coastal Development Permit Application
The Seaside Lagoon Rehabilitation Project is located within the California Coastal Zone and within an area subject to the California Coastal Commission's retained coastal development permit jurisdiction. As part of the entitlement process for the proposed rehabilitation, the City will need to obtain a Coastal Development Permit (CDP) from the California Coastal Commission.
The City has been coordinating with Coastal Commission staff during the development of the project. Staff has discussed the proposed project, including the reduced project scope directed by the City Council in April 2026, the project's recreational and public access components, water quality considerations, and sea level rise and coastal hazard issues. These discussions have helped identify information and technical analysis that will need to be addressed as part of the CDP application.
The CDP application will include the project plans and supporting technical materials necessary for the Commission's review. The application is expected to address, among other matters, the project's consistency with applicable Coastal Act policies; public access and recreational use of the site; coastal hazards and sea level rise; water quality; site design and visual resources; and construction-related impacts. The City's environmental documentation and applicable technical studies will be incorporated into the application materials as appropriate.
Following submittal, Coastal Commission staff will review the application for completeness and consistency with the Coastal Act and applicable policies. Commission staff may request additional information or revisions as part of its review. Once the application is complete and staff has completed its analysis, the project will be scheduled for consideration by the Coastal Commission at a publicly noticed meeting. Commission staff will prepare a staff report and recommendation, and the Commission will ultimately determine whether to approve, conditionally approve, or deny the CDP.
The purpose of the City Council's action at this time is to authorize staff to proceed with the final preparation and submittal of the Coastal Development Permit application. This action would initiate the Commission's formal review process and would not constitute approval of the CDP itself. The final project remains subject to the Coastal Commission's review and action.
Staff recommends the City Council authorize staff to proceed with final preparation and submittal of the Coastal Development Permit application for the Seaside Lagoon Rehabilitation Project and to continue coordination with California Coastal Commission staff throughout the permitting process. Staff also recommends the City Council approve the environmental exemption declaration.
COORDINATION
The Community Services Department coordinated this report with the Community Development and Public Works Departments.
FISCAL IMPACT
The estimated construction cost for the reduced-scope Phase 1 project is approximately $11.5 million, including Council’s direction from April 2026 on Lagoon depth, additional restroom facilities, and fence replacement. Approximately $10.9 million in combined State grant and City funding is currently available in the project account for construction. Additional Quimby funds are expected to be appropriated following the final contract bidding process if needed. Staff is also pursuing grant funding through the Statewide Park Development and Community Revitalization (SPP) Program to help support the project.
APPROVED BY:
Mike Witzansky, City Manager
ATTACHMENTS
• Conceptual Plans and Renderings
• Exemption Declaration