Using Landsat images to assess the impact of the 2013 Dakar rally in the Nazca-Ica sector of the Peruvian coast

“Since its beginnings, the Dakar has been driven by a collective passion for wide open spaces and exceptional natural sites.” (link)

How many of you know that the Rally Paris-Dakar does not exist anymore? Or, to be precise, that it is now simply called Dakar, even though it does not run to that city anymore? As stated on their website, it ha become “a nomadic international event”. Since 2009, the Dakar takes place in South America, and in 2012 and 2013 the route included Peru.

“With a strong attachment to respecting such sites, the rally organisers constantly seek out means to reduce its impact on the environment and to preserve the heritage of the countries that it crosses.” (link)

But a total of 449 vehicles in the competition (183 bikes, 38 quads, 153 cars and 75 trucks) plus an unknown number of support vehicles must have left traces. The question is: where, and how much area is affected? I wrote an email to the contact address given at the Dakar website to enquire about the actual route of the Dakar in the Nazca-Pisco segment in the Peruvian coastal desert. I never got an answer. I wrote some more emails to different people, but nobody could give me any details about the actual route.

A large (3.5 km long) Nasca geoglyph in December 2012, before being damaged by the 2013 Dakar. Limited damage by earlier offroad vehicle traffic is visible, but the feature itself was still mostly intact.

A large (3.5 km long) Nasca geoglyph in December 2012, before being damaged by the 2013 Dakar. Limited damage by earlier offroad vehicle traffic is visible, but the feature itself was still mostly intact.

What I usually do when I can’t be in the region that I’m interested in is to turn to remote sensing. Google Earth doesn’t have 2013 coverage of that area yet, so my next choice was the good old Landsat 7. It has been in orbit for 14 years now, and the images acquired after 2003 are affected by striping due to the failure of the scan line corrector (SLC). Fortunately, the area I was most interested in is also the area least affected by the SLC failure.

I downloaded two georeferenced Landsat scenes through Earth Explorer. These scenes were acquired shortly before (LE70060702012294CUB01, 20 October 2012) and after (LE70060702013008CUB00, 08 January 2013) the stage of the Dakar that crossed this part of the coast (07 January 2013). The panchromatic band 8 of the Landsat data was used because this is the band with the highest spatial resolution (15 m). A simple change detection returned those areas where reflectance has increased between the two dates. In many parts of the Peruvian desert, reflectance is increased by surface disturbance which exposes lighter sub-surfaces material that is otherwise covered by a dark desert pavement.

Results of change detection (areas where surface reflectance increased between 20 October 2012 and 08 January 2013). Yellow indicates likely effects of the Dakar, red indicates likely traces of other offroad traffic and construction.

Results of change detection (areas where surface reflectance increased between 20 October 2012 and 08 January 2013). Yellow indicates likely effects of the Dakar, red indicates likely traces of other offroad traffic and construction.

“In preparing its route, the Dakar has always devoted particular attention to preserving certain sites considered as sensitive. […] In Peru, the authorities of the Ministry of the Environment and the Ministry of Culture are involved in the creation of the route, which was jointly supervised by both of the ministries and the rally’s organisation teams.” (link)

Zooming in to an area where I had documented a Nasca geoglyph less than a month before the Dakar (the easternmost impacted area in the overview map; a few kilometres west from Santa Cruz) did not exactly make me feel good: Instead of following last year’s narrow route just outside the valley of the Rio Santa Cruz, the 2013 rally went right across the large geoglyph and several other archaeological sites. Some damage by offroad vehicles had occurred before the Dakar, much of it likely due to traffic related to the construction of new power pylons. Damage to the geoglyph by the Dakar however was devastating. Most of the vehicles in the rally were driven across the geoglyph. In contrast to previous damage by individual vehicles (which in most cases appear to have at least respected the numerous stone piles which make up the outline of the geoglyph), the sheer number and high velocity of the competition vehicles caused much greater destruction.

Comparison of Landsat 7 images of 20 October 2012 (left) and 08 January 2013 (middle) and reflectance changes between the two dates (right) show the impact of the 2013 Dakar. Geoglyphs are shown by yellow lines.

Comparison of Landsat 7 images of 20 October 2012 (left) and 08 January 2013 (middle) and reflectance changes between the two dates (right) show the impact of the 2013 Dakar. Geoglyphs are shown by yellow lines.

Not that nobody knew about the archaeology in the area – not far away, there are numerous large signs delimiting the Zona Arqueológica Pampa de Huayuri to both sides of the newly-built power pylons. The large geoglyph is very visible from a small hill right on the side of the Carretera Panamericana. So why was this archaeological site unnecessarily sacrified for a short-term “nomadic international event”?

The large Nasca geoglyph before being damaged by the 2013 Dakar, as seen in December 2012 from a hill on the side of the Carretera Panamericana.

The large Nasca geoglyph before being damaged by the 2013 Dakar, as seen in December 2012 from a hill on the side of the Carretera Panamericana.

P.S.: I would be grateful if somebody could contribute recent (after 07 January 2013) ground or aerial photographs.

P.S.2: A scientific paper on this topic has been published here: Hesse, R., in press. Combining Structure-from-Motion with high and intermediate resolution satellite images to document threats to archaeological heritage in arid environments. Journal of Cultural Heritage.

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2 thoughts on “Using Landsat images to assess the impact of the 2013 Dakar rally in the Nazca-Ica sector of the Peruvian coast

  1. Pingback: Dakar rally revisited: assessing the impact of the Ocober 2013 Dakar Challenge on archaeological heritage in coastal Peru | x years Before Present

  2. Pingback: Insistimos ante la necedad: el Dákar 2013 sí dañó las líneas de Nasca | Útero.Pe

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