I've been thinking about trying to depict some of the ideas from this conversation: https://slrpnk.net/post/12735795, using a sort of flat, diagram-like style similar to this old photobash:
Though a bit more complex. The obvious answer is 'don't build cities in swamps' but we already have a bunch of them, and though I don't live there I recognize that they have a lot of unique cultural and historical value and are peoples' homes, so I'm interested in what a solarpunk-adapted version of these would look like.
At the same time, I know basically nothing about New Orleans or similar areas, have no background in civil engineering, and no qualifications to make this except for the capability to do so using an old version of GIMP. So I'd absolutely love to identify issues, places to make improvements, and things that are missing now rather than once I've spent days chopping up images and finessing them into something coherent.
So what'd I get wrong? What's unworkable, out of scale, or dangerous? What style of buildings or cultural touchstones would you like to see? What kind of plants are missing?
I think these look great! It’s definitely possible to have elevated cities and this was a common solution for cities in flood-prone areas prior to modern flood-control infrastructure like dams and levees.
I would look to real world places for inspiration. Many seaside towns reserve the first floor for parking because of possible storm surges. Obviously parking isn’t really needed in a solarpunk city, I would think about uses for this space that can either survive or be easily moved in the case of flooding. Your ideas seem fine although the marketplace would have to be thoughtfully designed to make it portable.
My city of Sacramento historically was very flood prone (and arguably still is, if the levies fail). An interesting feature of our history is that the entire existing downtown was lifted up to reduce flooding risk—this included buildings, sidewalks, streets. Everything! Kind of amazing, really. This particular strategy does leave some issues—the space under many streets is hollow and basically unused, although maybe a creative use for it exists. It also poses challenges in planting trees and building in spaces above the tunnels since they were only designed for a specific load.
Older houses in Sacramento also often have an elevated first floor with external stairs which I find charming. Historically the first floor was used for carriages but today people either park there or store other items. So a similar strategy to what you have here, except the space is more enclosed. This works well here because the city is very flat, so even during floods there is little current. Areas with hilly topography or with coastal flooding need open space on the lower floor to allow moving water to pass under without damaging the structure.
I would also look into “sponge city” concepts with bioswales, rain gardens, etc. Another possible source of inspiration is the chinampas agricultural system in Mexico. This is an extremely productive agricultural system created by alternating deeper ditches/canals with elevated areas. This allows for more ecological diversity to grow different crops. While I don’t think it’s wise to convert existing swamps to this system due to their imperiled status, swamps aren’t particularly hospitable to have in our cities, so this could be another possible strategy to deal with seasonal flooding in existing settlements.
Climate-induced flooding is going to be a major challenge in the future and I think we’ve really only begun to reckon with this new reality.
I’m amazed the entire downtown was elevated. Do you know enough about that subject to have an opinion about elevating the Ferry Building in San Francisco? That has to be done for it to survive.
I realized I never replied to this. I'm definitely not an expert on this type of work--I would guess it's possible but the question in today's economic system is whether it's cost effective. I don't know the answer to that question.
Hi, I've been reading up on chinampas to try to get the details right and I was hoping to borrow some of your tree knowledge. Most sources mention a willow (Ahuejote (Salix bonplandiana)) and a cypress (Taxodium mucronatum) as the trees they used to reinforce/replace the underwater fences for soil retention. I'm sort of doing this picture as if its in New Orleans (for some of the buildings and other details anyways) and I think that's outside these specific trees current ranges. I was wondering: can I swap in any other cypress or willow since there are some native to Louisiana or would some cause problems?
Here's what I've got so far:
I'm probably not showing enough alternating layers of plant matter and mud, but I'm hoping it gets the point across. I've tried to find good sources, so far these diagrams are my favorites:
Some seem to show floating islands or like, a floating top layer with water underneath, inside the reed wall, which seems weird and inaccurate from what I've read. At this point, I mostly just want to get all the trees added, make sure they're realistic, and find some accurate roots to include to show how they reinforce the earthworks. From what I've read it sounds like willow and cypress just kind of put roots everywhere (I'm used to being able to find clearer diagrams for trees like pines and oaks, but have struggled to find good drawings for these. Also might add cypress knees in the waterways where they're really well established, we'll see. Then I'll start cleaning up the image and getting everything to match aesthetically.
Great work researching this!
In term of those trees--Taxodium distichum is very similar to T. mucronatum and will make a great replacement for a New Orleans version of chinampas. Many botanists now consider them part of the same species and it takes an expert to even tell them apart.
Willows are a more diverse group but in general they all grow well in flooded areas, so I am sure another species will work for this. I am not familiar with the specific species found in that area. I would probably just pick one that has a similar size and structure and call it good enough. Or you could just leave it as generic willows if you want since it might take some experimentation to pick the best species.
That said, I think other flood-tolerant trees could have their place in this system. Really it's just substantial woody plants that can grow in flooded, disturbed soil. I don't know the species in Louisiana super well since I don't live there but if there are other species that fit that bill I think you could also include them.
Thanks!! That's really good to know about Bald Cypress! That was my first guess for selecting trees. I ended up picking them and black willows, just based on range and look but I'll take your advice and leave the willows generic. I think these chinampas are kind of overgrown at the moment, but I figure the trees don't cover the entire thing, just the corners. I was able to find some roots to reference (mostly from washouts or other exposed roots) and tried to get the details right for cypress and willow (but I'm not an arborist and had trouble finding info on depth). Let me know what you think!
Generally, the depth that tree roots grow to varies greatly depending on soil conditions and species and isn't very well studied due to the difficulty and destructive nature of such research, so this might not be fully answerable. In most cases, tree roots won't grow very deep in poorly oxygenated, wet soils but I don't have much experience with the roots of these species, so they could be exceptions. Certainly their ability to survive and grow in these aquatic environments that are deadly to other trees suggests that they might be.
Another factor is that if there is a seasonal fluctuation in water level, which would be the case in most places on earth, then the roots can grow deeper during the dry season and might be partially underwater during the wet season, similar to what you've depicted here.
Thanks, I appreciate you taking the time to answer my questions!
Sure, happy to tall trees any time haha. They are a big interest of mine.