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The urban palimpsest

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5 min read

In 1229, Christian monks in Jerusalem, rummaging about for parchment, unbound a centuries-old codex, scraped off what was written on it, refolded the leaves in half, and wrote atop the now-smaller book, at right angles, new liturgical texts for the Holy Land’s faithful knights. After disappearing for centuries in a war or two, in the 1840s Doric Greek mathematics faintly visible under the liturgical text was spotted by a German Biblical scholar, who brought home a page that was translated, 75 years later, by Archimedean expert Johan Heiberg. Photographing the pages, he transcribed and published the results.

Disappearing again in the Greco-Turkish War of 1919-22, the palimpsest surfaced mysteriously in the ownership of ‘businessmen’ Louis Sirieux, who died in 1956 and whose daughter, unable to sell the manuscript privately, in 1998 put it up for auction in New York City. Sold to an anonymous private buyer, it was extensively studied with magnetic imaging, and in early 2009 new text was uncovered, a commentary on Aristotle attributed to Alexander of Aphrodisias. Under even that was a text by Hypereides, an Athenian politician from the fourth century BC. Today the whole palimpsest, with the only known copy of three works by Archimedes, is freely available online.

When it comes to American urbanization, cities are our palimpsest, and disasters scrape off what we have written. They are the unwished-for opportunity to envision the city anew.

Though the human tendency after a disaster is to return everything instantly to the status quo, cities benefit if we think of them as palimpsests, updated but with original details sneaking through, both physical and political. For a brief window of time, things are possible at speed and at scale, where regulations are waived so as not to obstruct the flood of empathy-driven capital arriving from government. What should a city do all at once, rather than in increments?

  1. Re-plat the grid. Every city is divided by streets and parcels – and as time passes, technology advances, buildings grow taller and communications get faster, the streets and land use patterns become too small to hold the newer, larger buildings that cities need. After London’s 1666 Great Fire, Charles II gave Christopher Wren carte blanche to redesign London …and to build what we now celebrate as St. Paul’s Cathedral.
  1. Replace the infrastructure wholesale. Just as one lays the carpeting before toting in the furniture, infrastructure should be laid down as a totality, with a strategic network, rather than snaked higgledy-piggledy through contorted rights of way. Patching or upgrading merely slows its inevitable obsolescence, but when the sewer pipes date from the 1850s, the roads from the 1930s, the building’s water piping from the time of lead (before 1979), or the insulation pre-Johns-Manville bankruptcy, a day comes when it all should simply disappear.
  1. Reclaim green space. Once a city is made, green space shrinks. Bit-by-bit it is intruded upon, often by transportation or power infrastructure that seems innocent enough at first but comes to overwhelm what remains of nature. Eventually it disappears entirely…until wholesale replacement of infrastructure offers a breath of fresh air. Park Avenue was created when the New York and Harlem Railroad was rerouted and the lines rebuilt underground. Central Park arose when a swampy landfill was drained, and its design commissioned by the state legislature specifically to enable pedestrians and carriages each to traverse the park without disturbing each other.

Scraping the city down to its palimpsest and then rebuilding it with a new plan is not only an opportunity to create a more efficient environment for inventing, earning and living, it also enables a society to practice selective active discard. After the disaster, what is preserved or restored is that which we rediscover or redisplay the historic, beloved or culturally unique – what we wish to remember of our shared past. What is imploded and trucked away are the past we would rather forget – the by-now-anachronistic smokestack industries that once were economic engines but are now CERCLA sites, or the ungainly or garish visual mistakes of bygone architectural fads.

We make these societal selections by our choices of tax incentives. Because the Historic Tax Credit is awarded to individual buildings, and only if the renovation meets scrutinized architectural standards, it enables both selection of the preservation-worthy and curation of the manner of that preservation.

When it comes to both remaking the grid and preserving the historic, tax incentives are critical, because they do two things:

  1. Incentivize at the margin. Historic preservation imposes a surcharge on redevelopment; the Historic Tax Credit can counterbalance that surcharge.
  1. Deliver soft equity. Properties need both debt (because it’s cheaper and reliably available in volume) and equity (to reassure the lender because it is paid only after the debt). But hard equity, which demands returns that are both rapid and large, is the enemy of public benefit, where the paybacks may be intangible, or shared publicly and given away for free. Soft equity, which can be contented by the return it gets solely from the tax incentives, is the friend of public benefit.

Post-disaster re-envisioning of the sustainable city also brings a further hidden gift – the focus of a national government’s full resources for benefit of a single impacted place. Because ad valorem real estate taxes are calculated based on property values, the city is derivatively the owner of roughly 20-25 percent of all assessable property within its boundaries. New money arriving in a flood, that repositions the city to be more sustainable and economically attractive going forward, is a federal grant that the city converts into invisible equity in the new buildings, new businesses and new homes built atop its palimpsest.

David A. Smith is founder and CEO of the Affordable Housing Institute, a Boston-based global nonprofit consultancy that works around the world (60 countries so far) accelerating affordable housing impact via program design, entity development and financial product innovations. Write him at dsmith@affordablehousinginstitute.org.