Planning for Flexibility & Wellness

The Ongoing Evolution of Natatorium Design

In 1868, the Cabot Street Bath opened in Boston, and according to the book Contested Waters: A Social History of Swimming in America, this was the first indoor swimming pool in the United States. Of course, chlorination and filtration systems weren't introduced until the next century, so swimming in a public pool was a pretty dicey proposition back then.



In our lifetimes, natatoriums have always been there, perhaps conjuring memories of vacations past, those first swimming lessons or attending a swim meet. And through the years they've evolved to keep up with changing demands, offering opportunities for leisure and entertainment, competition, fitness and exercise, instruction, therapy and socialization. And as technologies advance and users' desires change, aquatics planners and designers are always looking to improve and enhance the way that natatoriums operate and serve the public.


"As patrons have more frequent visits with longer stays, the actual and perceived health and wellness of a facility is in greater demand," said Dennis Berkshire, president of San Diego-based aquatic planning, design and consulting firm Aquatic Design Group. "To achieve this, engineers are turning to integrated computerized controls that monitor and manage the air and water systems. These systems have the capability of adjusting conditions based on bather use and other environmental conditions."


Berkshire explained that rather than a single disinfectant—chlorine, for example—these systems use both a primary and a secondary disinfection system. "The secondary disinfection is often ultraviolet or ozone disinfection systems. When managed correctly they can provide better air and water quality in the natatorium."

Another trend is to oversize the systems to allow them greater turnover of the air and water circulation and filtration systems, said Berkshire. "During peak loads the systems can increase the turnover and filtration of the water and air systems to maintain a quality chemical-free environment."

Scott Hester, president of Counsilman-Hunsaker, an aquatic planning and design firm headquartered in St. Louis, weighs in on how technology is driving designs. "Probably the biggest technology trend we are seeing today is with system controllers and the ability for equipment to communicate with each other. Today's chemical control systems have advanced to the point of being a pool system-wide controller whereby pumps, filters, heaters and chemical treatment systems are all communicating with each other.

"We are also seeing technology brought into the day-to-day operations in terms of record-keeping, pool testing, incident reporting, lifeguard certifications and other operational and risk management factors through the use of web-based digital documentation tools," said Hester.

Flexibility is another trend found in modern natatoriums. To serve the ever-increasing number of patrons, designs must be flexible to serve simultaneous use for a vast array of programs, explained Berkshire. "Water that is used for a competition swim team one hour may be used for recreation or swim lessons another. Spaces, pools and configurations must be designed to allow for multiple programs and uses to achieve a maximum utility and revenue potential for a facility."


Of course, Berkshire points out that mixed-use facilities require much more planning and forethought than a single-use facility, such as a competition pool. "Variables such as water temperature, water depth and pool configuration are all part of the pre-planning process. Planning must consider not only the multiple programs a facility is to support but also simultaneous programs as well. With the correct planning and construction, a facility can keep people and programs in the water all day long, which is key to a maximum operating cost recovery."

Of course, in these types of facilities, Berkshire stresses that staffing is also a strong consideration. "For example, a facility that will have lifeguards and constant supervision can stretch the limits in programming and amenities. Facilities that do not expect to have such staffing will be required to have a simpler design."

Given the expense of a natatorium building, single multiple-use pools were developed to provide a smaller footprint. And Berkshire explained how creating zones in that pool can serve multiple programs, allowing for a smaller building. "The disadvantage of this approach is that it can make staffing and supervision more difficult."


To provide the widest array of programming options, it's becoming increasingly common for facilities to provide multiple bodies of water, particularly since a single pool will provide a single water temperature. "Competitive water requires cooler water temperatures—typically 78 to 82 degrees—while recreation, learn-to-swim and therapy pools require warmer water temperatures—typically 82 to 90 degrees," said Berkshire. "By having multiple smaller pools, the water temperature and pool configurations are better suited to specific programs."

Additionally, with multiple smaller pools, a facility can close one or more of the pools if programming has less demand during certain times of the year, added Berkshire. "Since staffing is the single largest expense for facilities, this can reduce annual operating expenses and provide a better operating cost recovery."

Indoor pools provide many functions these days, and offerings are always being enhanced and expanded. "We continue to receive very positive feedback on wellness programming for all ages that isn't the conventional aqua aerobics that often targets senior populations," said Hester. "Especially at universities, aquatic managers are implementing classes for Aqua Physical (using tethered inflatable yoga-type mats that are great for balancing and core stabilization), Aqua Yoga, Underwater Spinning, Stand-Up Paddle Boarding, etc."

The city of Sioux Falls, S.D., retained Hester's firm to provide a city-wide aquatic facilities master plan, which led to the building of the Midco Aquatic Center, a 56,000-square-foot indoor state-of-the-art aquatic complex combining leisure areas with fitness and competition program spaces. The center houses three pools: a 50-meter competition pool housed in its own room, and recreation and warm-water pools which are located together in a different room. All feature ADA lifts.

The competition pool is used for swim meets and public lap swimming, according to Rich Carlson, a park district supervisor in Sioux Falls. It's also utilized by local swim clubs and two colleges. There are four diving boards, two basketball hoops, and on weekends, an inflatable volleyball court is set up.

Carlson said their mezzanine section has permanent bleacher seating for 500-plus spectators. "Parents are asked to sit in this area when their children have swim lessons. When we host large swim meets, the stands are mostly full." During these meets, food is also available for purchase. There are portable bleachers around the pool that teams use during swim meets.


The recreation pool—which features zero-depth/beach entry—is surrounded by windows to "bring the outside in." It offers open/recreational swim, water walking and swim lessons. Carlson describes some of its amenities, including a play feature with a large dump bucket, floating lily pads and netting for crossing, slide and spray features, a current channel and inflatable play features that are set up monthly.

"There's a waterslide that goes outside the facility and then back into the rec pool," said Carlson. "Also, once a month we have a movie on our video board and people are allowed to float on tubes, swim or sit in the mezzanine section. And we have a small splash pad outside the rec pool room that is open in the summer months."

The warm-water pool is used for recreation, swim lessons, water fitness classes and therapy. "On weekends it's very popular with kids because it's our warmest body of water."

Modern natatoriums are also upping the game when it comes to support areas, which can be another way to attract users and encourage them to stay longer. At the Midco Center there's a lounge with table seating, a 65-inch television, charging station, fireplace and concessions/vending. "The lobby area offers seating for people that use our concessions or a place to relax while their family and friends are swimming," said Carlson, adding that people like to have lunch or warm up during winter months if they're participating in activities at the adjoining park.


Equipment and systems that allow for more diverse use of a swimming pool are becoming more desired, according to Berkshire, explaining that these features allow facilities to attract patrons of all ages, increasing pool usage. He mentioned climbing walls, inflatable obstacle courses, underwater obstacle courses and drop-in exercise equipment such as bicycles, stair climbers and paddle board yoga. "The challenge with this equipment in a natatorium is adequate and accessible storage space. Overhead storage is being used for some of this equipment when it can be designed in a facility from the beginning."

The Midco Center has storage rooms for maintenance supplies and for recreation equipment, according to Carlson. There are also offices and four meeting/party rooms with pool access, which offer additional revenue-generating opportunities.

Moveable bulkheads allow multiple programs to occur in a single pool. "The bulkhead can also allow a pool to have shallow areas to support fitness and recreation while still maintaining deep water for a faster and better competition pool area", said Berkshire.

The Midco Center utilizes two bulkheads in the competition pool, which Carlson said are used daily to divide the pool into three bodies of water. "One section is for walking/public lap swim, the middle is for lap swim and practices, and the third section is a diving well so people can use the diving boards." Carlson said they're also useful for swim meets, creating two 25-yard pools for a total of 20 lanes. When setting up for long course, the two bulkheads are docked together on one side of the pool with starting blocks.


Natatorium wall and ceiling surfaces are now given more consideration for longevity, reflectivity, acoustics and corrosion resistance, according to Berkshire, who added that poor lighting in older facilities resulted in lackluster water. But he stresses that overhead lights must be serviceable. "To satisfy both concerns, modern lighting systems incorporate LED light sources with deck area serviceability, combined with surfaces that reflect the light to provide a bright and inviting environment. Natural lighting is often desired, but special attention must be given to control glare on the pool water."

Bershire explained that as facilities incorporate more programming, mechanical systems have had to evolve, since successful programs translate into more bather loads over longer periods of time. This results in greater loads of organics and pollutants to the pool water with less time for systems and staff to maintain the water. To account for this, higher turnover rates have been incorporated into modern pool designs, including the secondary and supplemental disinfection systems. "The evolution of variable frequency drive units has provided smart pump controls, allowing us to design pools with the ability to slow the water flow down when water quality and program usage allows," said Berkshire. "Wi-Fi connections to the smart pool controllers allow staff to monitor and control the systems with smart phones and tablets to ensure better water quality and reduce staffing."


For indoor facilities, controlling chloramines is a major consideration, and Berkshire said there is no silver bullet to solve this issue. "A coordinated effort of smart pool controllers, supplemental disinfectants such as ultraviolet, ozone and advanced oxidation systems, and natatorium air handling systems can ensure that chloramine issues are minimized or eliminated."

Air and water exchanges are another tool facilities are implementing. And new chemical controllers can now measure and monitor free versus total chlorines in the pool water, and control turnover rates, levels of supplemental disinfectants and other parameters to control chloramines, added Berkshire.

Hester agrees that the issue of chloramines continues to be a hot topic. "There are even industry suppliers who have developed building conditioning systems that are specific to removing chloramines from the surface of the pool, thereby improving indoor air quality." He mentions competition pool projects at Michigan State and Purdue that have taken a comprehensive re-design approach from the pool and mechanical engineering team. "The Model Aquatic Health Code (MAHC) also has a special ad hoc committee that's currently meeting and looking to set the bar with best industry practices."


In Alabama, the Huntsville Aquatics Center recently finished renovations, adding a 50-meter competition pool and warm-water instructional pool to the existing multipurpose pool. The three pools are located in separate areas of the facility, hosting recreation and lap swimming, recreational diving board use, water exercise and instruction, triathlons, swim and dive competitions, Paralympic and Special Olympic events, water polo and private parties/events.

Between the pools, there is seating for more than 2,000 spectators. "In the old natatorium we have collapsible bleacher seating for approximately 800. In the competition pool the stadium that overlooks the pool is all permanent seating. Over 300 of the seats have chair backs, arm rest and cup holders. The rest of the stadium is bleacher seating," said David Kalange, aqua activities manager in Huntsville. He added that the competition pool utilizes a bulkhead, allowing for different setup options.

Ricky Wilkinson is director of general services for the city of Huntsville, and he explained that the new pools use regenerative media filtration systems. The original pool system was converted to high-efficiency sand filters, and the heating and ventilation units were also upgraded.


The ventilation systems for the new pools were designed to combat the usual air quality issues, according to Wilkinson. "We have four dedicated units for the new competition pool and one for the instructional pool. These units pull roughly 85 to 90% outside fresh air into the pool environment and use the balance of makeup air from the environment. In both pools the ductwork was installed high in the area with the diffusers 'washing' air down the exterior walls. Each pool has a separate ducted exhaust. The grilles for the exhaust were placed low (at deck level in the competition pool) in an effort to pull the air from down the walls and across the pool surface to evacuate the chloramines."

Back at the Midco Aquatic Center, Carlson explained that all four bodies of water (including the splash pad) have their own filtration system and UV system. "Each body of water presents its own challenges based on bather load and time of year." The pools use regenerative media filters, and the competition pool uses two due to its size. "Each room has air-handling units to help control the air quality. If there's an issue with chloramines, we would superchlorinate the pool. Our maintenance staff does a great job tracking free chlorines to avoid any issues with chloramines," said Carlson.

Locker rooms and changing rooms are also critical components to successful natatoriums. "Family locker rooms have been a must-have for some time now. However, we're seeing a trend toward unisex spaces that in some cases are open to the natatorium space," said Hester. "In this approach lockers, cubbies, bench seating, sinks and even hair dryers are available and used by both men and women in a common space. This area is then surrounded by individual toilet rooms, changing rooms and showers."


Berkshire agrees that all-gender facilities are becoming standard, and added that as programming has diversified, the demands of locker rooms have also evolved. "Space for teams, seniors and children must be accounted for. Attention to spaces that can be monitored for safety as well as safe egress in emergencies must also be provided for."

As the cost of building new facilities continues to increase, Hester said that finding ways to repair or renovate existing facilities may be the only option for some to meet project budgets. "In these instances, there should be a balance of addressing both the physical as well as functional issues. When simply repairing physical issues in an older natatorium, millions of dollars can quickly be spent without any impact to the functionality of the facility."

Berkshire agrees, adding that many existing facilities are faced with providing updated amenities and programming. "Modernization projects need to address not only the pool but the building and mechanical systems as well. By evaluating existing deficiencies, programmatic need, desired needs, potential enhancements and anticipated needs for the next 20 years, a modernization project can be a huge success. Successful facilities can cater to the program needs of the entire community."

Simply put, modern natatorium design focuses on quality, according to Berkshire. "Quality of air, water and spaces. Better air and water quality mean a healthier atmosphere for patrons and employees." RM