Traditional ecological knowledge, TEK, is a cumulative body of knowledge, practice, and belief about the relationships of living beings with one another and their environment, handed down by cultural transmission (Berkes, 1999). It is usually studied within ethnobiology. Lo-TEK approaches the same knowledge as engineering. A root bridge, a reed hall, a sewage-fed fishpond, and a temple-run irrigation calendar are infrastructure in the plain sense, built things that carry loads, move water, treat waste, and feed cities, designed and refined over generations. The prefix inverts hi-tech. Industrial infrastructure tends to be capital-intensive, single-purpose, and to depreciate from the day it opens. These systems are labour-intensive and multi-purpose, and many of them strengthen over time because the organisms they are made of keep growing. The documented cases span 18 countries and four ecosystem types, mountains, forests, deserts, and wetlands (Watson, 2019), most of them outside state planning systems, which is one reason they have received little attention in sustainability practice. Vernacular architecture has been studied for decades; the difference here is that the subject is landscape and infrastructure rather than houses, and that the systems are described as technologies.

Living root bridges, reed halls, chinampas, and bheri ponds share several characteristics. They are built from living or locally abundant material, they do several jobs at once, and they strengthen with age and maintenance.

Four properties recur across the cases. The infrastructure is symbiotic: it depends on fig roots, willows, reeds, fish, or algae, and sustains them in turn. It is multi-generational, built over lifetimes and maintained through custom and inheritance rather than project budgets. It is low-energy, running on gravity, sunlight, growth, and labour. And it is multi-functional, so that a single system delivers food, water treatment, flood control, transport, habitat, and ceremony at once. The chinampa is a compact example. One field produces crops, filters lake water, shelters axolotl, and defines a canal that is also a road. These traits match what regenerative systems design tries to specify from first principles, and they are inseparable from place in the way bioregionalism demands: a subak makes no sense outside its watershed. They are also human-scale craft, legible, repairable, and taught by demonstration, which also makes them difficult to specify or procure through conventional contracts.

Institutions now count this knowledge formally. The UN Declaration on the Rights of Indigenous Peoples (2007) affirms rights to traditional knowledge, and the 2019 IPBES Global Assessment drew on Indigenous and local knowledge throughout, noting that lands managed by Indigenous peoples, roughly a quarter of the world's land surface, are declining more slowly than the rest. Seen this way, Lo-TEK documents a form of peripheral technology: practice that persisted outside industrial systems and is now being reconsidered. The framing carries three known risks. Treated as a category, TEK can reduce governance systems and relationships to data for outside researchers, valued only when useful to settler institutions (Whyte, 2013). A design audience can romanticize systems under severe pressure from land seizure, pollution, and outmigration, or borrow the form of a root bridge as a style while ignoring the 30 years of tending it took. And the systems resist scaling: a bheri pond works because a fishing cooperative sells the fish and a subak works because the temple calendar is binding, so a pond transplanted without the cooperative does not work as a treatment system. Projects that work tend to be led by the communities that hold the knowledge and to support their continuity rather than the export of forms. For designers, the main lesson is a broader definition of ecological intelligence, one in which people are among the species a landscape sustains and maintenance is part of the design.