Ancient adobe structures in Peru have come under threat due to El Nino-triggered rains, which could severely damage archeological sites that the country has strived to preserve.
Chan Chan, the ancient city in the Moche Valley outside Trujillo was once a thriving capital of the Chimor Empire, built to make use of the valley's precious water resources and irrigation systems over a thousand years ago.
Located on the northern coast of present-day Peru, about 480 km north of Lima, the ancient city is one of the largest and most important pre-Hispanic earthen architecture cities in the Americas. In 1986, it was inscribed on the World Heritage List for its extensive, hierarchically planned remains, which include remnants of the industrial, agricultural, and water management systems that sustained it.
Today, however, the clay architecture built centuries ago is vulnerable to flooding, soil erosion, and moisture damage.
"As the buildings are made of earth, rainwater erodes the surface of the walls and then seeps into the interior, creating grooves and voids through water-flow erosion. In the most severe cases, it may even affect the core structure of the walls, leading the wall or the whole structure to collapse," said Henry Gayoso Rullier, head of the Research, Conservation and Enhancement Unit of the Chan Chan Archaeological Complex Special Project.
To prevent rain erosion, archaeological conservators have installed roofs with drainage systems in key areas of the ancient city. Staff regularly repair the wall surfaces with chemical curing agents and mud.
"Depending on the specific area and conditions, we install roofs with drainage systems over certain sections to prevent rainwater from falling directly onto the walls, particularly those with decorative elements. For undecorated walls, we apply a protective layer to the top and then cover the sides and surfaces with a sacrificial layer, namely a thick coating of adobe and mud, to encase the entire structure. This ensures that when it rains, the water erodes this protective layer first, sparing the original wall from direct damage," said Rullier.
El Nino-triggered weather threatens preservation of Peru's world heritage site Chan Chan
