Qualla: Castanhão Dam

Castanhão Dam: Introduction

Sat, 18 Apr 2026 00:00:00 GMT

Photo credit Fabiobarros, CC BY-SA 4.0. The Jaguaribe was once called the largest seasonal river in the world - a river that ran in the wet months and turned to dust in the dry ones. For centuries, families in the Ceará sertão timed their lives to its rhythm. Then in 1995 the state started building a wall to change that. Seven years of construction later, on 23 December 2002, they closed the gates on the largest public reservoir in Brazil. The Castanhão Dam now holds 6.7 billion cubic meters of water - enough to cover 36,000 hectares when full - and keeps the Jaguaribe flowing year-round to a metropolitan region of nearly four million people. It is the reason Fortaleza has taps that work.

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Image: Fabiobarros | CC BY-SA 4.0

Castanhão Dam: A Dam a Century in the Making

Sat, 18 Apr 2026 00:00:00 GMT

Photo credit Brazil_location_map.svg: NordNordWest derivative work: Виктор В (talk), CC BY-SA 3.0. The idea of damming the Jaguaribe in this particular spot came from the Cunha family, who dominated the political oligarchy of the Ceará interior in the early twentieth century. They owned the Castanhão farm. The farm is now entirely submerged. The federal government's drought-re...

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Image: Brazil_location_map.svg: NordNordWest derivative work: Виктор В (talk) | CC BY-SA 3.0

Castanhão Dam: The Engineering

Sat, 18 Apr 2026 00:00:00 GMT

Photo credit Fabiobarros, CC BY-SA 4.0. The main dam wall stretches 1,500 meters long and 11 meters wide, pierced by 12 floodgates and four dispersing valves, with a 106-meter spillway and a crown elevation of 111 meters. The reservoir it creates stretches 58 kilometers from southwest to northeast along the Jaguaribe, ...

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Image: Fabiobarros | CC BY-SA 4.0

Castanhão Dam: Nova Jaguaribara

Sat, 18 Apr 2026 00:00:00 GMT

Photo credit Brazil_location_map.svg: NordNordWest derivative work: Виктор В (talk), CC BY-SA 3.0. The dam was controversial long before it was finished. Filling the reservoir required the flooding of the entire municipal seat of Jaguaribara - not just a few outlying farms, but the town itself. Thousands of people had to be relocated. A new town, Nova Jaguaribara, was construc...

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Image: Brazil_location_map.svg: NordNordWest derivative work: Виктор В (talk) | CC BY-SA 3.0

Castanhão Dam: The Drought That Almost Emptied It

Sat, 18 Apr 2026 00:00:00 GMT

Photo credit Brazil_location_map.svg: NordNordWest derivative work: Виктор В (talk), CC BY-SA 3.0. From 2012 through 2016, Ceará lived through its worst drought since 1910 - just 516 millimeters of rain across the worst years. The Castanhão, which had reached 97 percent of capacity in 2009, began a steady decline. By the end of 2012 it sat at 55 percent. By February 2016, rele...

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Image: Brazil_location_map.svg: NordNordWest derivative work: Виктор В (talk) | CC BY-SA 3.0

Castanhão Dam: What the Dam Holds

Sat, 18 Apr 2026 00:00:00 GMT

Photo credit Fabiobarros, CC BY-SA 4.0. On a normal year the Castanhão holds about 37 percent of Ceará's total water storage capacity. Roughly 3.8 million people in the Fortaleza metropolitan region depend on it for drinking water. Another 43,000 hectares of irrigated agriculture depend on it too, along with the port a...

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Image: Fabiobarros | CC BY-SA 4.0