# Why Colombia’s $4BN Dam Broke ![[images/Why-Colombias-4BN-Dam-Broke.webp]] **Creator:** The B1M · **Published:** 2026-01-28 · **Length:** 14:08 · [Watch on YouTube](https://www.youtube.com/watch?v=nOdeymwoZIk) > Caption source: YouTube **manual English (UK)** captions (`en-GB`), downloaded with **yt-dlp** on the **first attempt**. The manual track covers all of the narration but skips the **Brilliant** sponsor read (about 3:24–4:53). That gap was filled from the **auto-generated English** track: the first request hit an HTTP 429, and a spaced retry about 30 s later succeeded. TubeAlfred was not needed (0 credits). The manual track is the script and differs slightly from what is spoken in places. Timings here follow the auto track where the manual cues bunch together. The spoken close and outro differ from the manual text, as noted at 13:15. **No companion article was found on theb1m.com**: the site's 1,513-URL sitemap has no Colombia or Ituango dam page, and likely slugs return 404. Instead, facts were cross-checked against the Al Jazeera feature shown on screen at about 7:15, [Colombia's Hidroituango dam: 'There's a new war taking place'](https://www.aljazeera.com/features/2018/5/31/colombias-hidroituango-dam-theres-a-new-war-taking-place) (**Mary Atkinson**, 31 May 2018). It matches the **3,500** murders, **600** forced disappearances and **110,000** displacements (1990–2016), the reservoir covering mass graves, EPM's role, construction starting in **2010**, and the flooded engine room and the destroyed schools, health clinic and bridges. Al Jazeera puts the evacuation at "at least **24,000**" (the video says over 25,000) and the power share at "nearly **20 percent**" (the video says 17%). It also gives a projected **$5bn** budget, while the video's title says $4BN. The caption's "Columbia" is Colombia, "megaprojets" is megaprojects and "exasperated" means exacerbated. The **USD $100,000** acceleration contract (9:56) is reported as stated, though it looks implausibly small for a project of this size. YouTube chapters are used as section headings and line up with the captions. Screenshots come from the 720p stream (format 136). Host: **Fred Mills**. Paid promotion: **Brilliant** (30-day free trial at brilliant.org/TheB1M). The description also plugs Fred's book ***Mega Builds*** (pre-order), **Get Construction Talking** and *The World's Best Construction Podcast*. Additional footage and images: **Loren Moss**, **Noticias TN**, **Al Jazeera** (spelled "Al Jeezera" in the description), **EPM** and **El Tiempo**. A **VOA** logo also appears on screen at about 12:55. Special thanks: **Loren Moss** (financecolombia.com, @LorenMoss). ## Outline ### 0:00 Intro - **0:00** "This is the city of **Puerto Valdivia**. And it's being evacuated." **The largest dam Colombia has ever built is about to fail**, and the **25,000 people** who live downstream need to get out of the way, fast. - **0:26** This is the **Ituango Dam**, central to Colombia's ambition to become **energy independent** and part of its huge infrastructure building boom. - **0:35** It is **225 metres** high, "taller than a skyscraper". Behind it is a reservoir that can reach **127 km** in length and hold **2.72 billion cubic metres** of water. - **0:50** "And it's all about to come tumbling down." How did we get here? ![[images/Why-Colombias-4BN-Dam-Broke-t0003.webp]] ![[images/Why-Colombias-4BN-Dam-Broke-t0027.webp]] ![[images/Why-Colombias-4BN-Dam-Broke-t0050.webp]] ### 1:00 Evacuation - **0:59** On **13 May 2018** authorities sounded the alarm and evacuated, at first, just **600 residents** of Puerto Valdivia. A few days later the **entire town** was abandoned and its residents moved to temporary shelters. - **1:15** The flooding destroyed **59 homes, two schools, a health centre**, critical infrastructure and the town's **famous bridge**. What was left became a **ghost town**. - **1:24** The mass displacement made existing social problems worse in a region already hit by **violence and instability**. - **1:33** This was only a taste of what a full collapse could do; **only the side tunnels** had failed. A news clip warns that if **Hidroituango** breaks, it would endanger the **120,000 people** of the **Cauca River Basin**. - **1:50** Even with the all-clear to return, few wanted to. **More than 400 families** were homeless. - **1:59** Worse, this was no ancient dam in need of repair. Ituango was **brand new**, due to be finished **just weeks after** disaster struck: "a modern, state of the art project to lift the country to a higher level." ![[images/Why-Colombias-4BN-Dam-Broke-t0064.webp]] ![[images/Why-Colombias-4BN-Dam-Broke-t0076.webp]] ![[images/Why-Colombias-4BN-Dam-Broke-t0095.webp]] ![[images/Why-Colombias-4BN-Dam-Broke-t0115.webp]] ### 2:18 Biggest dam ever - **2:18** It was designed to be **Colombia's largest hydroelectric project**, eventually supplying **17%** of the country's electricity. - **2:26** Colombia needed the power. Its population grew from **33 million in 1990** to **46 million** just before construction began, and to **more than 53 million** today: "like adding the entire country of **Australia**" in a few decades. - **2:48** The grid was struggling. A huge dam could prevent **shortages and blackouts** and reduce reliance on **expensive thermal plants**. - **3:00** **Hydropower** already supplies most of Colombia's electricity and is one of the **cheapest** energy sources in the region. But many of its hydro plants date from the **1970s, or the 1990s at the latest** (on screen: **Salvajina Dam, 1985**). Newer, more efficient, higher-capacity plants would let the old ones be scaled back and retired. - **3:24** Sponsor segment (**Brilliant**, about 3:24–4:53, from the auto track). Brilliant teaches maths, engineering, AI and science through visual, interactive lessons, "like a gym for the brain", with personalised goals and streaks. It is pitched as a way to keep New Year's resolutions and get "your 2026 back on track". "Speaking of getting back on track, let's get back down to Colombia." ![[images/Why-Colombias-4BN-Dam-Broke-t0142.webp]] ![[images/Why-Colombias-4BN-Dam-Broke-t0165.webp]] ![[images/Why-Colombias-4BN-Dam-Broke-t0195.webp]] ![[images/Why-Colombias-4BN-Dam-Broke-t0240.webp]] ### 4:55 Taming the river - **4:53** Colombia's mighty rivers provide **agricultural abundance** but can be **unpredictable**. Besides generating power, the dam would **tame the Cauca River**. - **5:08** The **Cauca** is Colombia's **second-largest river** after the **Magdalena**. It winds **965 km** through the Andes and major cities before joining the Magdalena near **Magangué**. - **5:20** **Indigenous** and **Afro-Colombian** communities depend on it for fishing and transport. Millions live in its valley, one of the most densely populated **Andean corridors**. - **5:32** It supports the **Valle del Cauca**, one of Colombia's most productive farming regions. It irrigates **more than 200,000 hectares of sugarcane**, and the Cauca Valley produces **over 90% of Colombia's sugar** and **100% of its ethanol fuel blends**, with irrigation drawn straight from the river. - **5:59** Higher up the basin, in the **Eje Cafetero** (Coffee Axis), the Cauca's tributaries sustain another famous export: **coffee**. - **6:10** In all, the river sustains **one of the richest farming regions in Latin America** and food security for millions. - **6:19** "Where the river gives, it can also take away." **Seasonal flooding** has caused crop destruction, livestock losses, soil erosion and damage to infrastructure. Hidroituango's reservoir adds **flood-control capacity**: it can lower peak flows in rainy seasons, protect riverbank communities and their fields, and cut recovery costs. - **6:47** "From every angle, this was supposed to be a win." ![[images/Why-Colombias-4BN-Dam-Broke-t0300.webp]] ![[images/Why-Colombias-4BN-Dam-Broke-t0330.webp]] ![[images/Why-Colombias-4BN-Dam-Broke-t0360.webp]] ![[images/Why-Colombias-4BN-Dam-Broke-t0390.webp]] ### 6:50 An impossible location - **6:50** **Construction began in 2010.** The site in the **Central Andes** was incredibly difficult, and not just geographically. - **7:00** Politically, the region has been "well, violent", thanks to "Colombia's other famous export." The reservoir is thought to cover **dozens of mass graves**. - **7:14** Experts estimate **3,500 murders, 600 forced disappearances and 110,000 displacements** in the region between **1990 and 2016** (on screen: Al Jazeera's 2018 feature). - **7:25** The dam was **financed with public money**, and the government marketed it as a step away from that violence: a project to bring **peace and prosperity** "to a place that had never really known it." ![[images/Why-Colombias-4BN-Dam-Broke-t0418.webp]] ![[images/Why-Colombias-4BN-Dam-Broke-t0435.webp]] ![[images/Why-Colombias-4BN-Dam-Broke-t0450.webp]] ### 7:44 Building a megadam - **7:40** "Say it with us now": the first step in building any dam is **diverting the river**, usually through temporary **cofferdams** or channels that leave the site dry. That holds for the largest, highest and smallest dams alike. - **8:00** "Really take a look at it." The **canyon walls are deep**, and there is nowhere else for the water to go. Engineers had **one option: tunnels through the mountains**. - **8:15** Even reaching the site meant building **roads on cliff-like slopes** and carrying huge equipment around **narrow mountain passes**. - **8:25** In **2012**, as main construction of the **diversion tunnels** was beginning, the project became mired in controversy over a "nefarious" **bidding process**, **alleged corruption** and delay after delay. Work on the tunnels went ahead anyway. - **8:38** **Tunnel boring machines** could not fit, so the tunnels were dug "the old fashioned way. With **explosives**." In **drill-and-blast**, rigs drill holes in the rock face and charges fire in a timed sequence to fracture the rock. Loaders and trucks remove the spoil, and **shotcrete** (sprayed concrete), **rock bolts, steel ribs and mesh** stabilise the cavity. - **9:18** The work needed constant **ventilation, drainage and monitoring** to prevent collapses. The Central Andes is one of the most **geologically active** regions in the world, where landslides and earthquakes are "par for the course". - **9:34** By **2014** the tunnels were complete and the river could be diverted. "This is important", because it led to the disaster four years later. ![[images/Why-Colombias-4BN-Dam-Broke-t0480.webp]] ![[images/Why-Colombias-4BN-Dam-Broke-t0520.webp]] ![[images/Why-Colombias-4BN-Dam-Broke-t0555.webp]] ### 9:48 Rushed construction - **9:48** **Empresas Públicas de Medellín (EPM)**, the **state-owned utility** that designed and built the dam (on screen: EPM headquarters, Medellín). - **9:56** By **2015** the project was well behind schedule; it should have been finished the year before. EPM signed a "**USD $100,000**" contract (as stated) to speed things up. Work ran **24/7** and recovered **18 months** of delay, "but **shortcuts were taken**." - **10:14** EPM had strong **financial incentives** to stay on schedule. It would receive **USD $22.3 million** if the dam started delivering energy as promised **before December**. It had already counted the dam's revenue in its budget, so it risked losing **credit standing** and "falling into a financial hole". - **10:34** By **2017** the dam was **70% complete**. By **13 May 2018** it was just weeks from completion. - **10:44** Then one of the dam's **diversion tunnels collapsed**. Authorities ordered **more than 25,000 people** downstream to evacuate, fearing the dam could burst. ![[images/Why-Colombias-4BN-Dam-Broke-t0595.webp]] ![[images/Why-Colombias-4BN-Dam-Broke-t0610.webp]] ![[images/Why-Colombias-4BN-Dam-Broke-t0640.webp]] ### 10:55 Disaster strikes - **10:55** So how did it happen? The tunnels were dug through **highly fractured rock**, and the ground proved even less stable than engineers expected. The tunnels crossed **fault lines and crushed rock** prone to sudden deformation. **Groundwater had softened the rock**, so it could hold less weight, and rock quality changed from strong to crumbly **within a few metres**. - **11:10** Far more of the Cauca was flowing through the system. The dry season was over, and this was "a particularly nasty wet one." Even a **small deformation** in a tunnel lining could cause cracking, let water in or lead to larger structural damage. - **11:30** "And that is exactly what happened." A deformation **blocked one diversion tunnel**, and water pressure built up behind it until the tunnel, now a **pressurised cavity**, collapsed. With its main route gone, the river **overwhelmed the other two tunnels**, and within days all of them were destabilised or had collapsed. "**They lost control of the river.**" - **11:50** Engineers had to **raise the dam in a matter of weeks**, still working 24/7 with dump trucks and loaders, but now "motivated not by money, but by fear". The wall reached **225 metres**, high enough to hold back the rising water. - **12:00** They then opened the **spillway**, which had **never been used or even tested**. It gave the Cauca a controlled outlet and restored **partial stability**, "but it was far from over." - **12:15** The consequences included unplanned **flooding of the machine house** (the powerhouse), **structural damage to the intake components** and months of interrupted construction. - **12:26** A **Dutch underwater construction specialist** isolated the dam's **intake structures** underwater. It built **custom mechanical plugs** that let **divers seal off and dewater** entire sections. - **12:40** **New diversion tunnels** were built, and many of the old ones were abandoned. **Four more turbines** are still to come online, and **full completion is now due in 2027**. - **12:55** The lessons: "**money and political pressure cannot substitute for rigorous engineering practice**." **Local communities were not properly consulted**, and **environmental impact reports** ignored the enormous risk and human cost of a failure. - **13:15** Spoken close: the project shows the huge scale of infrastructure and its power to change the lives of millions, "often for the better, but sometimes for the worse." The manual (script) track reads instead: reach for the sky with ambitious megaprojects, but "remain at least a little grounded" so they don't change your country for the worse. - **13:35** Outro: Brilliant sponsor thanks and a subscribe call ("if you thought this video was **damn good**… make damn sure you're subscribed"). The manual track has a plug for *The World's Best Construction Podcast* here instead. ![[images/Why-Colombias-4BN-Dam-Broke-t0665.webp]] ![[images/Why-Colombias-4BN-Dam-Broke-t0700.webp]] ![[images/Why-Colombias-4BN-Dam-Broke-t0725.webp]] ![[images/Why-Colombias-4BN-Dam-Broke-t0750.webp]] ![[images/Why-Colombias-4BN-Dam-Broke-t0775.webp]] ![[images/Why-Colombias-4BN-Dam-Broke-t0805.webp]] ## Things mentioned ### Dams and infrastructure - **Hidroituango / Ituango Dam** (Proyecto Hidroeléctrico Ituango) on the **Cauca River**, Antioquia: Colombia's largest dam and hydro project. It is **225 m** high with a reservoir up to **127 km** long holding **2.72 billion m³**, and is meant to supply **17%** of Colombia's electricity. Construction began in **2010**, the diversion tunnels were finished in **2014** and a tunnel collapsed on **13 May 2018**. Completion is due in **2027**, with four turbines still to install. - **Diversion tunnels**: three tunnels driven by drill-and-blast through fractured, faulted rock. A deformation-induced blockage and collapse in 2018 led to the failure of all of them, and new tunnels have since been built. - **Spillway**: opened before it had ever been used or tested, to give the river a controlled outlet. - **Machine house / powerhouse** and **intake structures**: flooded and damaged, then isolated with custom mechanical plugs by Dutch divers. - **Salvajina Dam** (1985): shown as an example of Colombia's ageing hydro fleet. - **Puerto Valdivia's bridge**: the town's famous bridge, destroyed in the 2018 flooding. ### Places - **Puerto Valdivia**: evacuated town downstream of the dam, which became a ghost town. **Medellín**: home of EPM. - **Cauca River**: 965 km long and Colombia's second-largest after the **Magdalena**, which it joins near **Magangué**. Its basin has **120,000** people at risk. - **Valle del Cauca** (sugarcane and ethanol) and the **Eje Cafetero** (coffee); **Central Andes** - **Australia**: used for the population comparison ### Engineering - River diversion with **cofferdams** and channels vs **diversion tunnels**; **tunnel boring machines (TBMs)**, which could not reach the site - **Drill-and-blast** excavation, **shotcrete**, **rock bolts**, **steel ribs**, **mesh**, ventilation, drainage and monitoring - Failure mechanism: fractured and crushed rock, **fault lines**, rock softened by **groundwater**, variable rock quality and wet-season flows. A **lining deformation** caused a blockage, the tunnel became a **pressurised cavity** and collapsed, and the remaining tunnels were overwhelmed. - Emergency response: the dam was raised to 225 m in weeks, the **untested spillway** was opened and intakes were sealed underwater with custom **mechanical plugs** ### Money, politics and society - **Public financing**, marketed as a route to peace and prosperity - **2012** controversy: "nefarious" bidding, **alleged corruption** and delays - **EPM** incentives: a "USD $100,000" acceleration contract (as stated), **USD $22.3 million** for early energy before December and revenue already booked in its budget - Regional violence: **3,500** murders, **600** forced disappearances and **110,000** displacements (1990–2016); **mass graves** believed to lie under the reservoir; an oblique reference to cocaine as "Colombia's other famous export" - **Indigenous** and **Afro-Colombian** river communities; poor **community consultation**; **environmental impact reports** that ignored the risk to life ### Agriculture and energy - **Hydropower** is Colombia's main and cheapest power source; **thermal plants** are the costly alternative - **Sugarcane**: more than 200,000 ha, over 90% of Colombia's sugar and 100% of its **ethanol fuel blends**; **coffee** from the Eje Cafetero - **Flood control**: lowering peak flows to protect riverbank farms and communities ### People and organisations - **Fred Mills** (host); **Empresas Públicas de Medellín (EPM)**; an unnamed **Dutch underwater construction specialist** - **Loren Moss** (special thanks; financecolombia.com) - Footage credits: Loren Moss, Noticias TN, Al Jazeera, EPM, El Tiempo (a VOA logo also appears on screen) - **Al Jazeera** feature by **Mary Atkinson** (31 May 2018), shown on screen and used here for cross-checking ### Sponsor and The B1M - **Brilliant**: sponsor (maths, engineering, AI and science; 30-day free trial at brilliant.org/TheB1M) - ***Mega Builds*** (Fred's book, pre-order); **Get Construction Talking**; *The World's Best Construction Podcast* ### Figures and facts - 225 m high; 127 km reservoir; 2.72 billion m³; 17% of national electricity - 13 May 2018: an initial 600 evacuated, rising to more than 25,000; 59 homes, two schools and a health centre destroyed; more than 400 families homeless; 120,000 at risk in the Cauca Basin - Population: 33 million (1990), 46 million (before construction), more than 53 million (today) - Construction 2010; controversy 2012; tunnels done 2014; 70% complete in 2017; 18 months of delay recovered; completion due 2027 - **Since the video** (Colombian press, 2026): four of the eight units are running and units 5–8 are being rebuilt. Units 5 and 6 are slated for late 2027 and units 7 and 8 for 2028 (El Colombiano). The southern powerhouse works finished 18 days early in July 2026 (Portafolio). ## Biographies ### Fred Mills Co-founder and on-camera host of **The B1M**. He frames the story as a brand-new megaproject that came within weeks of completion before its diversion tunnels failed. He covers why Colombia needed the power and flood control, the violence around the site and the money pressure on EPM. He closes on the lesson that political and financial pressure cannot replace rigorous engineering. His book ***Mega Builds*** is plugged in the description. ### Empresas Públicas de Medellín (EPM) Colombia's **state-owned utility**, owned by the city of Medellín, which designed and built Hidroituango. The video describes how EPM paid to speed up construction, the incentives it had to deliver power early and the revenue it had already booked. It was in charge of the 2018 emergency response and is still completing the remaining turbines. ### Loren Moss Medellín-based journalist and publisher behind **Finance Colombia** (financecolombia.com) and a YouTube channel (@LorenMoss) covering Colombian business and infrastructure. The B1M credits him for footage and gives him special thanks. ### Mary Atkinson (Al Jazeera) Reporter on Al Jazeera's 31 May 2018 feature *[Colombia's Hidroituango dam: 'There's a new war taking place'](https://www.aljazeera.com/features/2018/5/31/colombias-hidroituango-dam-theres-a-new-war-taking-place)*, which appears on screen in the video. It documents the evacuation, the conflict-era violence and mass graves along the Cauca, and the protests against the dam. It is used here in place of a B1M companion article to cross-check names and figures.