For years, we’ve written about water levels on Europe’s rivers. Usually the questions come in some variation of these: Will there be enough water for my cruise? Is the Rhine too low? Should I avoid the Danube in August?

After what we’ve seen this summer, I think there’s a more interesting question to ask: How is river cruising adapting to a changing climate?

Because it is adapting. This summer has certainly tested the industry, particularly on the Rhine and Danube, the two great arteries of European river cruising. Low water on portions of those rivers disrupted numerous sailings, while other waterways, including the Elbe, have faced their own challenges.

But that distinction matters. Europe’s rivers are not one hydrological system. Conditions on the Seine, Rhône, Saône or Douro can be very different from conditions on the Rhine or Danube, just as the managed canals used by hotel barges present another set of circumstances entirely. Historically low water affected the Rhine, Danube and other European waterways, and Viking reported that more than half of its European river-cruise days were affected during part of the third quarter. That’s extraordinary.

But something else extraordinary happened: Most cruises still operated. That doesn’t mean every passenger received exactly the vacation he or she expected. There were changed embarkation points, buses, altered itineraries, ship swaps and cancellations. You’ll find some of their stories in the comments of our water levels discussion.

But increasingly, the river cruise industry’s response to low water isn’t simply to stop sailing. It is to find another way to operate.

The Ship Swap Has Become Much More Sophisticated

Ship swaps aren’t new. We were writing about them long before this summer. But they’re evolving from an emergency workaround into something that cruise lines can actually design their fleets around.

Viking is probably the clearest example. It operates identical Longships in opposite directions along the same rivers. When a section becomes unnavigable, passengers can leave one ship, typically go on an excursion, and continue their journey aboard an identical sister ship waiting on the other side. Ideally, you return to the same cabin number you left that morning. Your luggage is already there.

AmaWaterways is doing much the same thing and says it is deliberately building sister ships so swaps can be made as seamlessly as possible. Think about what that means. Climate resilience is becoming part of fleet planning.

The Ships Themselves Are Changing

That’s happening below the waterline too. AmaWaterways says its forthcoming AmaRudi will have a shallower draft than AmaMagna, specifically giving it greater ability to operate when rivers are low. Draft is simply how deeply a ship sits in the water. Every additional inch can matter when you’re trying to cross a shallow section of the Danube or Rhine.

So naval architects have an interesting problem: How do you continue giving passengers larger cabins, restaurants, pools and all the amenities we’ve come to expect while designing a vessel that needs less water beneath it? We’re going to see more answers to that question.

And another change is happening in the engine room. As we write in one of our new stories this week, 15 new river ships are being equipped with large battery systems, including vessels being built for AmaWaterways and Uniworld.

They’re not completely electric ships. They’re hybrids. But batteries can allow them to operate portions of their journeys with less dependence on conventional engines, potentially reducing emissions, noise and vibration. That’s another form of adaptation—this time aimed at reducing river cruising’s environmental footprint rather than simply dealing with the consequences of a warmer climate.

We’re Adapting As Travelers, Too

Passengers are changing as well. For years, summer was almost automatically considered prime time for European river cruising. We’re no longer sure that’s the case for everyone. Spring and fall have become increasingly attractive. Temperatures are generally cooler. Crowds can be smaller. And depending on the river and the year, water conditions may be more favorable.

That doesn’t mean we’re going to tell you that May is “safe” and August is “dangerous.” Rivers don’t work that way. We’re been doing this long enough to know that high water can cause problems just as low water can. A river that looks troublesome one week can recover quickly after rainfall.

There is no water-level guarantee when you book a river cruise months in advance. Instead, we need to become smarter about risk rather than trying to eliminate it. That means looking at the river, the season, the ship and—something increasingly important—how the cruise line responds when things don’t go according to plan.

The Cost Of Adaptation

There’s also a financial side to all of this. In another story this week, we look at estimates reported by Barron’s suggesting that this summer’s low water could cost Viking $30 million to $50 million in lost revenue, along with roughly $150 million in future-cruise vouchers issued to affected passengers.

That’s a reminder that ship swaps, buses, rerouting passengers, issuing credits and repositioning vessels aren’t free. Resilience costs money. Building new ships with shallower drafts costs money. Battery systems cost money. Maintaining fleets large enough to position sister ships on opposite sides of a trouble spot costs money. Some of those costs will inevitably become part of the economics of river cruising.

We’re Still Cruising Europe’s Rivers

None of this makes us less enthusiastic about river cruising. Ralph has been hosting river cruises and barge trips in Europe for years, and he’ll continue doing so.

But we need to stop talking about every drought as though it is an isolated event that will eventually pass and everything will return to the way it was. Europe’s climate is changing. River cruising will change with it.

Some of that change will happen in ways passengers never see: shallower hulls, batteries beneath the decks, sophisticated weather and river monitoring, ships being strategically positioned hundreds of miles apart.

Other changes will be obvious. We may cruise more in April, May, September and October. Itineraries may become more flexible. And travelers may start considering a cruise line’s ability to handle disruption almost as carefully as they consider its cabins and cuisine.

That’s not a gloomy outlook. It’s actually a fairly encouraging one. River cruising exists because humans learned how to work with rivers—locks, dams, canals, ports and ships all represent adaptations we’ve made over centuries.

Now we’re entering another period of adaptation. The rivers are changing. And so are the ships that sail them.