Grand Solmar at Rancho San Lucas in Cabo San Lucas, Mexico
By Juan Padilla
Nestled between sapphire seas and dramatic desert landscapes, Grand Solmar at Rancho San Lucas offers its guests a massive lagoon pool with a lazy river, waterslides, several infinity pools and multiple swim-up bars for casual dining. Comfortably hidden away within the exclusive Rancho San Lucas private resort community, just north of bustling Cabo San Lucas, this luxury resort is above and beyond ordinary.
Constructed by award-winning builder Xavier Alvarez of MAXA Watershapes, the lagoon is particularly impressive because it is essentially an artificial seawater reservoir completely filled with salt water from the adjacent Pacific Ocean. The lagoon offers users a beach entry complete with sandy shores to imitate the feel of the ocean within the resort. But the location of the lagoon and its unique features provided multiple challenges to the construction and maintenance of the pool. From the challenge of building on top of a sand dune to battling the corrosion and sanitation issues associated with salt water, this lagoon construction was anything but simple.
The Grand Solmar is a half-acre project located on the Pacific Ocean side of Baja California. However, the beach near the resort has rough waters so the developers wanted to create the feel of the ocean within the resort itself. As a result, the lagoon was conceived from the necessity to create the feeling of the ocean, complete with ocean salt water pumped directly into the lagoon. The resort itself has its own desalination plant that supplies the resort's water so a portion of the water is pumped directly into the pool from the same pumping system used by the desalination plant. This lagoon reservoir, according to HKS Inc., the landscape architect on the project, was created to provide users with a beach experience while also acting as a reservoir to be used by the development desalination plant. The seawater is pumped directly from the ocean from a well located at the beach.
Baja California is essentially a desert next to the ocean, and building a pool in the desert isn't easy. "One of the biggest challenges was building this pool on top of what is essentially a sand dune," said Xavier Alvarez, owner of MAXA Watershapes, the design, engineering and builder of the lagoon at the Grand Solmar. "Dealing with all the sand and high winds was a constant struggle, especially from October through February when the area experiences particularly high winds."
Overall, the lagoon is composed of 4,560 square meters of water surface and holds roughly 900,000 gallons of water. Depths of the lagoon range from a maximum depth of almost 10 feet in some areas with beach entries in several areas as well as shallow portions where the water is only 6 inches to 3 feet in depth.
The pool was built using reinforced concrete walls lined with PVC that was then covered with a layer of shotcrete to protect the vinyl. To help control the sand from getting into the lagoon, MAXA also built a bern around the pool to help control invading sand.
The lagoon offers multiple water features throughout, including cascading rock water features that spray and aerate the water which simultaneously help with water circulation and flow. There is also a 10-foot-deep area with a diving tower. The two main water features—installed on opposite ends—provide the appearance of a natural waterfall and help to oxygenate the water. Due to the amount of water required to feed these features, four specialized pumps, offering a total flowrate of 2,400 gallons per minute, were installed. Additional features adjacent to the lagoon that use non-saltwater including a show fountain with 14 bubblers and two spas—one on each end. Also, there are two waterslides and a children's water play area next to the lagoon. All of these additional features require a separate equipment room far away from the main lagoon pump room to avoid long plumbing runs as well as to minimize the saltwater effects on the equipment. The water supply for these features comes directly from its own desalinization plant.
The biggest challenge on this project has been the use of ocean water within the lagoon. "To begin with, saltwater corrodes everything, and I mean everything," explained Alvarez. "From hinges and rails to pump room equipment, even wood is adversely affected by saltwater."
As a result, MAXA Watershapes did lot of learning and adjusting to come up with a pump room design configuration that could deal with the ocean salt water as well as create a maintenance and cleaning program for the lagoon. "We couldn't use the same type of pump room equipment on this project that we would use with a standard, non-saltwater pool," Alvarez said. "We ended up working very closely with Pentair to choose the correct mix of equipment that not only would work in this situation but would also have readily available parts in Cabo for repair and maintenance."
The water chemistry of the saltwater in the lagoon has been one of the biggest challenges for MAXA, because they replace the ocean water entirely every 72 hours. As a result, it becomes challenging to balance the water. The pH in the water is extremely high because the water is ocean saltwater. "With pH levels at 8 to 8.2, the sanitizers can become ineffective so we decided to install two, very large Pentair BioShield UV units that are 12 inches in diameter," explained Alvarez.
The UV has been highly effective at enhancing the power of the chemicals in the water especially if there are longer stretches of time between the replacement of the water. The UV is also helpful during the rainy season in Cabo San Lucas. "Our rainy season is almost like having multiple small hurricanes," Alvarez said. The winds and rain introduce large amounts of dirt, sand and rain that quickly alter the chemical balance of the lagoon water.
Especially when the lagoon first opened, the sand entering the lagoon was a serious challenge. "Sometimes we had to bring in an army of workers as we drained the lagoon to quickly, manually clean up all the sand in the vessel and refill it with water from the ocean in less than 12 hours."
This was especially the case after storms in the rainy season. Eventually MAXA was able to introduce the use of robotic cleaners into the lagoon vessel to reduce the amount of manual cleaning labor. "The robotic cleaners are terrific but unfortunately we are constantly replacing parts on the cleaners because the ocean salt water corrodes the metal components of the cleaners," Alvarez explained.
Because of the size, shape and varying depths of the lagoon, water flow and circulation were very strategically planned. To ensure proper circulation, the pool builder designed 87 floor returns fed with seven 6-inch lines, nine 6-inch anti-entrapment engineered floor suction lines, two 8-inch floor suction lines, eight 6-inch return lines for the water features, and six 6-inch skimmer lines. The flowrate was estimated at 4,872 gpm, and the total water feature flowrate was 2,400 gpm. The circulation system was designed to provide for a fast turnover rate when required, such as moments after a storm or high winds. Under normal circumstances, the equipment functions at an optimal flowrate to keep the water quality in check. "We also designed our own special skimmer returns," said Alvarez. In conjunction with the landscape architect's directions, the custom skimmers were made of masonry to blend in with the lagoon's esthetic design.
The equipment for the lagoon is comprised of eight Pentair THS sand filters, seven Pentair EQ pumps each of which is 10 HP in size, three variable frequency drives (VFDs) and two BioShield UV units. Both the filters and pumps require some special maintenance routines due to the nature of the ocean's salt water in the lagoon as well as the sand and silt that flows regularly into the lagoon's waters.
Basically, the lagoon's environment requires a lot of backwashing. "One of the reasons we really like using the THS horizontal sand filters is that they have a hatch that allows us to visually inspect the sand directly, to see how dirty it is getting," explained Alvarez. "Sometimes the sand looks like chocolate!" As a result, maintaining the sand sometimes requires that the maintenance team manually clean the sand in the filters. The sand in the lagoon's filters is backwashed weekly and manually cleaned about every two months—though most of the debris tends to accumulate at the top of the filter.
The EQ pumps have very few parts that corrode because even the motor on these pumps is totally enclosed and fan cooled (TEFC). However there is quite a bit of plumbing both for the lagoon as well as for the many water features that are a part of in the lagoon—both waterfalls and water bubblers. Initially, the plumbing was experiencing an extreme "hammer effect" and so MAXA worked with Pentair and determined that three VFDs could give the pumps the soft start needed to stop the hammer effect. Prior to adding the drives, the plumbing was experiencing some violent shaking and the pressure was such that it caused the plumbing connection to fail. However the VFDs allow the pump to 'soft start' allowing the system to be pressurized little by little. And conversely, it also allows the system to soft stop as well, decreasing the pressure and eliminating the hammer effect. In addition, the soft start and stop help protect the pump motor reducing the amount of maintenance and replacement of parts. This is particularly important in an area that is fairly isolated from major distribution centers, potentially making replacement parts scarce. There has been a learning curve associated with the VFDs in this operation, as standard protocol in Mexico has always been to change the pump motor bearings annually, as a part of a regular maintenance program. With the VFDs it's important that maintenance personnel understand they no longer need open the pump motor. That in fact, it will reduce the life of the motor to do so. As the new TEFC motors on the Pentair EQ pumps in combination with the Acu Drive XS variable frequency drive, allow maintenance personnel to do virtually nothing in terms of maintenance on the pumps and is why Pentair is able to offer a longer warranty on these pumps.
In addition to the protection to the pumps and the removing of the hammer effect on the plumbing, the variable frequency drives have also provided added energy savings to the property owners. By being able to dial the pumps to the exact flow rate required, the pumps are able to use less energy.
The variable speed drives and the UV units are fairly self-sufficient. The UV units require very little maintenance outside of making sure the lamp is clean and functioning. The VFDs require minimal maintenance and, in this salty environment, just need to be checked for corrosion and cleaned or repaired as needed.
Becoming 'Lagoon' Experts
The lagoon at Grand Solmar has now been operating for two years. MAXA Watershapes took care of every detail in house until every kink was worked out of the system. Last year MAXA Watershapes turned everything over to the resort's maintenance department and supervised as needed. The results are so successful and the owners of the resort have been so pleased with the results that they are now building an extension or 'Lagoon Part 2' within the resort.
"We have now become 'experts' on ocean saltwater pools," explained Alvarez. "Because we do all the building and engineering, we are able to control the outcome and ensure success."
MAXA Watershapes has been building in the Cabo San Lucas areas for the past 20 years and is known for putting a lot of heart into its projects. "Because we do everything in house, we are knowledgeable about the process in ways that other construction companies aren't able to offer. Our customers trust us because we pride ourselves on being educated by attending seminars and training in the U.S., following all APSP codes, putting an emphasis on detail and therefore we are able to guarantee superior results," Alvarez said.
Now MAXA Watershapes can add "salt-water lagoon experts" to their list of qualifications.
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