I wouldn’t say that the water loss is tiny. I’m assuming average temperatures between 90-100° F when operating and low humidity (<30%) and I found a source saying that the city of pheonix estimated that an Olympic swimming pool loses 2500-5000 gallons of water per month. That has mostly to do with surface area but I’m assuming they have at least one of those pools in the park, maybe multiple. Could be up to 15,000 gallons/month just for pools alone.
Then we talk about the water slides which, if you’ve ever been on a water slide, you know that they waste water. Water leaking from the slides may be gallons an hour and the agitation of the water will speed up evaporation. I’d say each slide loses somewhere around 10-20 gallons an hour as a guess. You multiply that by 15 slides and you’re getting 150 gallons per hour, 12,000 gallons a day.
So not to put it lightly but this one park could be losing over a million gallons of water a year. Easily. And in a desert that’s nothing to scoff at.
I did all my math before researching but I found an article from the guardian that uses very similar numbers. Mine are higher but this park is also bigger.
I was under the impression that the bulk of water consumption for modern water parks was from flushing toilets bathroom facilities, so I’ll have to defer to your assumption of 20 gallons per hour for a slide. If a slide can accommodate 20 kids per hour, that means 1 gallon per kid, which seems pretty reasonable.
When we talk water consumption in regard to bathroom facilities, you might get into the weeds a little bit. In most modern countries, water from waste facilities is not “wasted” and is instead treated and returned to reservoirs or rivers. Upon being returned, the contaminants are diluted by the natural water source and then are eaten and processed by organisms that will rebalance things. And many areas in the US draw from aquifers that are replenished by adding this water back into the ground which takes years and further filters the water.
The reason evaporation is a problem is because we don’t have to consider those complicated factors when the water is returned to the air. It is purely wasted in the sense that it will be dispersed in the air and we have no control over where it goes after that. If you have an abundance of water and your aquifer is at equilibrium, no problem. But if you’re in a desert and having to desalinate water from an ocean to fill your water park, that’s a big issue. Basically it’s hard to know exactly how bad this park would be without context of its resource systems.