Water Johads: A Low-Tech Alternative to Mega-Dams in India

water johad india

When the British colonized India, they imposed their own system of water management, which included the building of large-scale dams, sewers, and irrigation channels. This high-tech approach continues today, as the World Bank is urging India to build enormous dam projects to fight drought and depleted aquifers. The Indian government has followed its advice. Its first Prime Minister, Jawaharlal Nehru, called dams the “Temples of modern India”. Since then, India has built over 5,000 dams and large reservoirs. [1]

However, before the British arrived, people on the subcontinent used traditional low-cost, low-tech engineering to collect rainwater for thousands of years. This involved the placement of thousands of small structures throughout rural areas which, in one way or another, catch excess rainwater from the monsoon months and allow it to slowly percolate into the groundwater during the dry season. To maintain and manage these structures, community-based management schemes were necessary. However, these were actively discouraged during British rule and following independence. As a result, in the 20th century many of these small reservoirs fell into disrepair.

[Read more…]

Micromachines: Decentralized Urban Services in South-Asia

VelochariotArchitects Damien Antoni and Lydia Blasco have compiled an interesting document that focuses on small-scale technology in countries like India, Vietnam, Cambodia and Thailand. They photographed, and made technical drawings of miniature taxi’s, family run water turbines, domestic rain harvesting systems, pedal powered kitchens, home digesters, and the like.

The architects consider their work to be a toolbox, a starting point for thinking outside the conventional norms and recepies. They argue that decentralized services are more flexible, provide more autonomy, and are more efficient in space, energy and materials.

Antoni and Blasco present, in their own words, an equivalent to Neufert’s “Architect’s data“, the book for architects that records standardized dimensions for centralized systems. “Micromachins” is written in French but the visuals dominate.

“Micromachins”, Damien Antoni and Lydia Blasco, 2011 [download the page to get the high resolution PDF-document]. Thanks to Yann Philippe Tastevin. Update: the architects have added a new link with colour pictures and English translation.

Covered Bridges: How to Build and Rebuild Them

covered bridges how to build and rebuild them“This manual is intended to provide comprehensive support to those involved with maintaining, assessing, strengthening, or rehabilitating covered bridges, especially heavy timber truss bridges. At one time, the United States reportedly had 14,000 of these unique bridges dotting the countryside over a surprisingly large area. Now, fewer than 900 of the historic structures survive.

Timber bridges initially were built without coverings and failed in just a few years because of rot and deterioration, because chemical wood preservatives were not available or used. Builders familiar with the construction of houses, barns, and large community structures naturally added siding and roofs to help protect the bridge. They understood that the covering would soon pay for itself. They believed that regular maintenance and occasional replacement of the light covering was far easier and cheaper than building an entirely new bridge. North American covered bridges still serve after nearly 200 years, due in part to the continued soundness of the trusses, which was possible only with these protective coverings.”

Covered Bridge Manual“, 327 pages, US Department of Transportation, 2005. Via Arquitectura y madera. Previously: wooden bridges / wooden pipelines. Picture by Rainer Ebert.

Engineering for the Ecological Age: Lessons from History

Lower Calyx dome under construction All three tile layers are visible photos Michael Ramage

Engineering for the ecological age: lessons from history” (video) by John Ochsendorf. Skip the extremely irritating introduction to the speaker and start at 10:50. Via Ecodemica. Related: Tiles as a substitute for steel: the art of the timbrel vault & Timbrel vaulting in South Africa. Photo: Michael Ramage.

Human Powered Dredger (1859)

human powered dredger

Click on the illustration below to see the plan in high resolution. Source: “Mémoires et compte rendu des traveaux de la société des ingénieurs civils, Vol.12, 1859“.

Dredger

Wooden Bridges

wooden bridge new

This wooden bridge (length 32 metres, width 12 metres, height 16 metres) was inaugurated on April 15th in Sneek, the Netherlands. The “Krúsrak” is the first wooden bridge in the world that can support the heaviest load class of 60 tons. Its life expectancy is 80 years.

Thanks to a chemical treatment of the softwood, the bridge can withstand insects, fungi and the harsh weather conditions in the most northern province of the Netherlands (Friesland). Wooden bridges require much less energy to construct than steel or concrete bridges.

Only the road-surface of the “Krúsrak” is made of steel – originally it was planned to be of wood, too, but then it should have been 2 metres thick. More information here (in English) and here (in Dutch).

Related: Covered bridges – how to build and rebuild them. Also: wooden pipelines.