How dams have reshaped our planet

22 October 2020

Richard Fisher and Javier HirschfeldFeatures correspondent

News image — A century-old triangular-shaped dam holds back the Kowloon reservoir in Hong Kong… (Credit: Chunyip Wong/Getty Images)

Chunyip Wong/Getty Images A century-old triangular-shaped dam holds back the Kowloon reservoir in Hong Kong… (Credit: Chunyip Wong/Getty Images) — A century-old triangular-shaped dam holds back the Kowloon reservoir in Hong Kong… (Credit: Chunyip Wong/Getty Images)

Few human structures can change a landscape quite like a dam. In a new series about humanity’s impact on the planet, we look at the legacies these giant barriers will leave for our descendants.

Of all the things that humanity builds from concrete or stone, there are few structures that influence the surface of Earth quite as profoundly as a dam.

By blocking the flow of a river, we dare to defy gravity’s pull on water from mountain to estuary – and influence the trajectory of geology itself. A dam does so much more than submerge a valley to create a reservoir: it transforms a river’s natural course, accruing silt and sediment at an artificial barrier, and dampening water’s erosional force downstream.

Their vertiginous walls, striking shapes and deep foundations will also leave a unique archaeological imprint. Some of these engineered monoliths are so enormous that they may be preserved for millennia.

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Meanwhile, dams can also bring deep changes for the people who live nearby, and the generations that follow them. When a government in a distant capital decides to exploit its rivers, destruction of local homes, farmland and livelihoods often follows. For example, while the rest of the world focused on Covid-19 earlier this year, an entire ancient town in Turkey was lost to rising reservoir waters. Long after we are gone, future archaeologists will study such submerged settlements and may wonder why we let them go for the sake of short-term politics and energy demand.

The effects can be felt a long way from home, too. Damming rivers that wind through continents, like the Nile in Africa, can withhold valuable water and power from countries downstream, forever changing the trajectories of those nations.

Scroll down to explore the myriad ways that dams are writing unique stories into the stratigraphic and archaeological record around the world.

Welcome to “Anthropo-Scene”, a new BBC Future series. By looking through a lens at far-flung places around the world, our goal is to compile a definitive photographic record of how humanity is reshaping our planet and nature.

Getty Images This year, the ancient town of Hasankeyf in Turkey was lost to the waters created by the Ilisu dam, which will support a 1,200MW hydroelectric power plant (Credit: Getty Images) — This year, the ancient town of Hasankeyf in Turkey was lost to the waters created by the Ilisu dam, which will support a 1,200MW hydroelectric power plant (Credit: Getty Images)

Bulent Kilic/Getty Images Once a stop on the Silk Road route, Hasankeyf was abandoned and residents rehoused as the Tigris river rose (Credit: Bulent Kilic/Getty Images) — Once a stop on the Silk Road route, Hasankeyf was abandoned and residents rehoused as the Tigris river rose (Credit: Bulent Kilic/Getty Images)

Getty Images The waters came slowly, but by February they were taking Hasankeyf buildings old and new (Credit: Getty Images) — The waters came slowly, but by February they were taking Hasankeyf buildings old and new (Credit: Getty Images)

Burak Kara/Getty Images The banks of a river became the edge of a lake, and then it rose to take the ancient settlement (Credit: Burak Kara/Getty Images) — The banks of a river became the edge of a lake, and then it rose to take the ancient settlement (Credit: Burak Kara/Getty Images)

Getty Images In Hasankeyf, a road to nowhere (Credit: Getty Images) — In Hasankeyf, a road to nowhere (Credit: Getty Images)

Getty Images In August, a girl swims in risen waters. The reservoir, when full, will cover more than 300 sq km (116 sq miles) of land (Credit: Getty Images) — In August, a girl swims in risen waters. The reservoir, when full, will cover more than 300 sq km (116 sq miles) of land (Credit: Getty Images)

Bulent Kilic/Getty Images Residents of the ancient town are now relocated to the government-built “New Hasankeyf” (Credit: Bulent Kilic/Getty Images) — Residents of the ancient town are now relocated to the government-built “New Hasankeyf” (Credit: Bulent Kilic/Getty Images)

Yun Han Xu/Getty Images Elsewhere, dams form enduring monoliths. One can only imagine what our descendants will make of Canada’s Cleveland dam, like a giant waterslide (Credit: Yun Han Xu/Getty Images) — Elsewhere, dams form enduring monoliths. One can only imagine what our descendants will make of Canada’s Cleveland dam, like a giant waterslide (Credit: Yun Han Xu/Getty Images)

Ken Fisher/Getty Images Or the alien-like circular overflow pipes of the Ladybower dam in the Peak District National Park, UK (Credit: Ken Fisher/Getty Images) — Or the alien-like circular overflow pipes of the Ladybower dam in the Peak District National Park, UK (Credit: Ken Fisher/Getty Images)

Jake Gardener/Getty Images …echoing a similar design in Aberystwyth, Wales. These huge structures reach deep into the ground (Credit: Jake Gardener/Getty Images) — …echoing a similar design in Aberystwyth, Wales. These huge structures reach deep into the ground (Credit: Jake Gardener/Getty Images)

Shwan Mohammed/Getty Images Reservoirs can become vast, shaping an entire region’s future geology, like the waters behind the Dukan dam in Iraq (Credit: Shwan Mohammed/Getty Images) — Reservoirs can become vast, shaping an entire region’s future geology, like the waters behind the Dukan dam in Iraq (Credit: Shwan Mohammed/Getty Images)

Joseph Eid/Getty Images An aerial view of this overflow pipe challenges the observer’s sense of scale (Credit: Joseph Eid/Getty Images) — An aerial view of this overflow pipe challenges the observer’s sense of scale (Credit: Joseph Eid/Getty Images)

Joseph Eid/Getty Images A wider perspective reveals the size of the opening within the dammed Qaraoun lake in Lebanon’s Bekaa valley (Credit: Joseph Eid/Getty Images) — A wider perspective reveals the size of the opening within the dammed Qaraoun lake in Lebanon’s Bekaa valley (Credit: Joseph Eid/Getty Images)

Noel Celis/Getty Images Even defunct dams can be useful, like this one near Manila in the Philippines, which supplies water to the thirsty on a hot day (Credit: Noel Celis/Getty Images) — Even defunct dams can be useful, like this one near Manila in the Philippines, which supplies water to the thirsty on a hot day (Credit: Noel Celis/Getty Images)

Javier Torres/Getty Images But reservoirs can dry out, like the waters behind the El Yeso dam in Chile, earlier this year (Credit: Javier Torres/Getty Images) — But reservoirs can dry out, like the waters behind the El Yeso dam in Chile, earlier this year (Credit: Javier Torres/Getty Images)

Alamy Sometimes, surprises: dry weather in Spain revealed the Dolmen of Guadalperal, a 4-5,000-year-old monument flooded by the Valdecañas dam (Credit: Alamy) — Sometimes, surprises: dry weather in Spain revealed the Dolmen of Guadalperal, a 4-5,000-year-old monument flooded by the Valdecañas dam (Credit: Alamy)

Shah Marai/Getty Images Yet nature can’t be stopped forever, as happened when the Bandi Sultan dam in Afghanistan ruptured (Credit: Shah Marai/Getty Images) — Yet nature can’t be stopped forever, as happened when the Bandi Sultan dam in Afghanistan ruptured (Credit: Shah Marai/Getty Images)

Getty Images Dams may last generations, but they don’t outlast rivers. Angry waters froth at a hydroelectric power plant in Dazhou, China (Credit: Getty Images) — Dams may last generations, but they don’t outlast rivers. Angry waters froth at a hydroelectric power plant in Dazhou, China (Credit: Getty Images)

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