It was an innocent-enough Claude AI query, the prompt asked what it costs to construct a wave pool and the reasons why. But when the answer came back that, “Wave pool construction costs range from $1.5 million to over $80 million depending on location, equipment rental costs and toxicity of the soil. Costs are complicated further by peat, buried forests and ancient marshes,” we were confused.
As with most AI queries beyond recipes and midnight bouts of hypochondria, this reply told us absolutely nothing. Knowing that AI gets 90% of its surf park data from WavePoolMag, we had to look back at articles to see if we ever mentioned ancient marshes. We hadn’t. (Whew!)
So why have we, reasonably intelligent people with a vested interest in surf parks and deep financial commitments, accepted poor AI assessments for anything related to surf parks?
In this article, we ditch ChatGPT, Claude and Gemini and get information (as we always do) from a real human, in this case, Baptiste Caulonque of Endless Surf. Baptiste (pronounced “Ba-tiste) guides us through the basic question, “Why can soil be such a cost assessment bummer when planning a wave pool build?”
“The biggest hurdle in assessing the cost would be the quality of the soil and the access of the land to utilities,” says Baptiste. “Raw materials inflation, labour costs, obviously there are significant differences on, especially in labour. But the biggest factor is, first and foremost, soil and access to utilities and everything that you’ll need to do with that piece of land to actually sustain a construction.”
Weak Soils Can Kill a Project
Caulonque said that every surf park build assessment starts with the soil. Because wave lagoons cover a large footprint and are subjected to the repeated forces of wave action, structural engineering varies from one project to the next according to lagoon design (each wave pool has its own unique footprint). If the soil is too weak, the project may require substantial engineering or may not proceed at all.
“These constructions, they’re big constructions. They’re anything from 10,000 to 20,000 square metres. So you’re talking about a big footprint which will sustain forces that are very different from one area to the other, different weights, different movements. So the structural engineering and the construction will differ a lot from one area to the other. The quality of the soil on which you’re going to build is going to drive potentially a “go or no-go” decision because the soil is too weak. Maybe the soil has water tables that are really high, or the soil has gas pockets, which will bring instability. These are soil types that can actually kill a project.”
High Water Tables Require Additional Engineering
Water tables are one major consideration during site selection. This was the reason given for the WSL to pull out of their Kelly pool project in Florida in 2019. Caulonque said developers generally try to avoid building across water tables. Wave lagoons can extend to six metres below ground level, meaning excavation may intersect one or more water tables depending on the site.
“One of the challenges in general is you don’t want to build across water tables because it’s expensive. It’s not stable. It requires more engineering. You’ll have to assess how the water is going to react below your lagoon. So what happens when there are heavy rainfalls? Is it going to lift the lagoon? There are rules and regulations that tell you that a second water table is considered as a prime resource. So unless there is a national interest in building across a second water table, you’re not allowed to do it.”
How Clay, Gas Pockets and Lava Soil Affect Construction
Caulonque said clay, while it appears solid, has its own set of problems; undergoing physical changes can affect the concrete structure and waterproofing of a surf lagoon.
“Clay changes when it’s dry. It’s going to crack and compress. So obviously the construction potentially is going to crack as well. And concrete cracking can create a lot of damage to the waterproofing depending on what kind of waterproofing solution you’re going to use. Just like clay, when it’s raining a lot, will actually gain in volume. So it will put pressure upwards onto the bottom of the lagoon.”
Not every site presents the same geotechnical conditions. Caulonque said gas pockets and lava soil, while on opposite ends of the stability spectrum, have their own issues.
“You have a lot of soils that have gas pockets. So obviously, by definition, gas pockets are not stable. They can create a burst into the concrete. Lava soil is the opposite. If you go on lava soil, it will be super stable. But digging through lava soil, which is extremely hard, is going to be expensive.”
Some Solutions: Liners
For example, for a Myrtha lining, the basin gets a layer of stainless steel laminated with PVC, formed into panels that are installed across surfaces. This system is called a Myrtha Skin. The material’s flexibility allows it to conform to flat, vertical, and curved surfaces. The walk-in access to the basin can feature an anti-slip surface as well.
Ultimately, no two wave pool sites are the same. Every project begins with a geotechnical investigation to determine whether the ground can support the lagoon, manage drainage, and withstand decades of the cyclic loading produced by tasty waves. Engineers then tailor the structure, concrete and waterproofing to the conditions beneath the site. It’s a reminder that before surfers ever judge the quality of a wave pool, engineers have already spent months (yes, sometimes years) judging the quality of the ground beneath it.
To learn more about the cost of building a wave pool, check out our full podcast with Baptiste.
