The Gualcarque is a modest river by any hydrological measure. It flows eastward for about 2.4 miles from its source in the Opalaca reserve to the reserve's border, where the only road along its entire course -- the V-608 -- crosses it. From there it turns north through the Montana Verde wildlife reserve. The water emerges from a geothermal zone associated with the Azacualpa thermal springs southwest of Lake Yojoa, part of an extensional tectonic system with Holocene volcanic activity. Water samples from the Gualcarque recorded temperatures as high as 52.5 degrees Celsius. But the river's significance to the Lenca communities along its banks is not geothermal. It is existential. They fish in it, wash in it, irrigate their corn and bean fields with it, and drink from it. Their spiritual traditions hold it sacred. When construction machinery arrived in 2006, the Lenca understood immediately what they stood to lose.

Beginning in 2006, the Chinese state company Sinohydro, the World Bank's International Finance Corporation, and Honduran company Desarrollos Energeticos S.A. -- known as DESA -- planned four hydroelectric dams on the Gualcarque, the largest being the Agua Zarca Dam. The project would create a 300-meter-long reservoir, divert three kilometers of the river, and generate 22 megawatts of hydroelectric power. DESA financed the work through loans from the Dutch development bank FMO, the Finnish FinnFund, and the Central American Bank of Economic Integration. The Lenca communities along the river said they had never been consulted, as required under international law. Community members in Rio Blanco turned to the Council of Popular and Indigenous Organizations of Honduras -- COPINH -- for help. Together with Berta Caceres, a Lenca woman and co-founder of COPINH, they organized local assemblies that formally voted against the dam, filed complaints with government authorities in Tegucigalpa, and brought their case to the Inter-American Human Rights Commission.

In 2012, DESA began construction on land it had acquired, destroying corn and bean fields, fruit trees, and coffee plantations. By March 2013, DESA security officers had blocked community access to the river itself. The Lenca responded with a street blockade. They were met with violence, detention, and torture. In July 2013, during a peaceful protest near the dam construction site, Tomas Garcia was shot and killed, allegedly by members of the Honduran Army. Berta Caceres continued organizing despite escalating threats against her life. She won the Goldman Environmental Prize in 2015 for her work defending the Gualcarque. On March 3, 2016, gunmen entered her home in La Esperanza and shot her dead. She was 44 years old, a mother of four, and one of the most prominent indigenous rights defenders in the Americas. In 2021, a Honduran court found Roberto David Castillo, president of DESA, guilty of planning her murder and hiring the gunmen.

The killings did not silence the opposition. They amplified it. International attention intensified after Caceres's assassination, and the financial institutions backing the Agua Zarca project came under enormous pressure. In late 2013, Sinohydro had already terminated its contract with DESA. The IFC, citing human rights concerns, withdrew its funding. In June 2017, FMO and FinnFund suspended and ultimately withdrew their financing as well. The dam project, for which people had fought and died, collapsed not on the riverbank but in boardrooms in The Hague and Helsinki. The Gualcarque still flows through its reserves, still crosses under the V-608, still empties into the Rio Grande de Otoro. The Lenca communities still draw their water from it. Berta Caceres's words remain: giving your life for the protection of the rivers is giving your life for the well-being of humanity. She meant it in every sense the phrase can carry.