My mind is still wandering the high desert before the dawn, breathing in the crisp dry air, the countless stars and the infinite depths of the spaces between them, marvelling at the austere beauty of the nearly inhospitable landscape. But at the same time my mind is furiously digging and building and planting wind-breaks and water storage, solar collecting systems that soak up the sun from dawn til dusk and store as much energy as possible in living water and living soil, making possible an ever more diverse array of life forms, even as they huddle together in the sheltering earth, holding fast against the cold dry empty entropy of space, consciousnesses burning through the long night.
A pond inside of a cave seems like it wouldn’t lose as much water to evaporation, nor lose as much heat to the night sky. What if you built some hollow spaces into the inner slopes of the crater and then used them to store water and heat?
Built into the south-facing interior slopes of the crater you could have a big insulated cavern/earth-sheltered-greenhouse that was almost completely glazed on the south sides soaking up the sun all day. At night you’d probably want some thermal shutters / insulative curtains. Inside of this solar-heated cavern could be multiple ponds aerated by cascading waterfalls, along with swimming, bathing, and relaxation spaces like showers, pools, hot tub, saunas, integrated with aquaculture and perhaps even tropical forest gardening.
Water heated in this space could be thermo-siphoned and/or pumped up to higher cisterns for storage and even perhaps periodically used to flood swales. Such flood irrigating might be done as often as monthly but would probably always be during the early pre-dawn hours, (mainly to reduce evaporation losses but perhaps also to add a little bit of extra heat at a time when it could potentially prevent an overnight frost.) Alternatively, sub-surface irrigation techniques could be used to further minimize evaporation while providing water to plants via wicking (capillary action.) Perhaps water could be piped into a series of unglazed, ceramic pots (ollas) buried in the rhizosphere.
Built into the non-south-facing interior slopes of the crater could also be caverns of varying sizes, some of which could be intentionally flooded to different degrees. Examples of some of these possible cavern aquaculture systems include: an underwater cave perhaps connected to ponds or chinampas outside, or just a chinampa or finger of a pond that is partly inside and partly outside of a cave, perhaps a duck island on a pond in a cave, or even just a trickle of clean water into a drinking bowl in the shade and shelter of a cave. Basically lots of habitable hollow spaces accessible to a variety of animals, (fish, crustaceans, reptiles, amphibians, ducks, chickens, bats, wild birds, small mammals, maybe sheep, almost certainly pigs during at least some phases for their prodigious pond-gleying, etc.) integrated with the cultivation of fungi and more shade-tolerant, water-loving plants.
A temporary soil-filled column connecting the submerged floor of a cavern with the tree-inhabited earth above the cavern might wick water up and eventually fill with tree roots. Once the roots reached the floor, the soil container could be removed, leaving a column of exposed living tree roots that would continue to move water up via capillary action. Maybe a variety of such dendro-rhizo-sculptures, (seriously rad and gnarly art, statues, tools, tool handles, furniture, and even structural components like frames for walls, roofs, doors, windows, and staircases,) could be grown from tree roots with enough time, patience, and foresight.
Of course, lots more structural complexity and cost is added when you start talking about building in caverns. And it adds complexity to the order of operations too, the transition from flattish land to a terraced crater with multiple caverns built in. The vast majority of the earthworks could happen almost all at once if nearly all the caverns were built and ready to be buried, but a more gradual transition might be more appropriate. Lots of questions. Still thinking about all this, but figured I would share some of my thoughts. I’d love to hear some of your thoughts and feedback, too!