What might the Tidal Basin look like in the next century? Here are some ideas for its soggy future.

The National Mall’s Tidal Basin is home to the city’s iconic cherry blossom trees, which provide a backdrop for the annual National Cherry Blossom Festival, not to mention countless spring outings, family photo shoots and, nowadays, Instagram photos.

It’s also, well, tidal — which means it’s prone to flood, a situation that’s only expected to get worse as climate change and sea level rise take their toll in the coming decades.

So the National Park Service, the Trust for the National Mall and the National Trust for Historic Preservation came up with the National Mall Tidal Basin Ideas Lab to do something about it. They asked five prominent landscape architecture firms to lay out how the Tidal Basin might evolve over the next 150 years.

What the firms came up with runs the gamut, from doubling down on engineering to keeping the Potomac River at bay to building elevated walkways, from replanting the cherry blossoms on the ballfields of West Potomac Park to allowing each…