# Arroio São Luiz dam emergency in São Marcos > Live situation record from CLSTR: https://clstr.news/situations/arroio-so-luiz-dam-emergency-in-so-marcos > Updated: 2026-09-27T10:57:48.000Z. Sources: 37. Developments: 2. Following heavy rainfall in Rio Grande do Sul, the Arroio São Luiz dam in São Marcos was placed under a red alert due to structural cracks and leaks in the spillway and buttress. The dam, containing approximately 420,000 cubic meters of water, posed an imminent collapse risk, leading to the evacuation of roughly 170 residents and significant utility disruptions affecting thousands of properties. To mitigate the danger, technical teams from Corsan and the Municipal Water and Sewage Department utilized high-power pumps to reduce reservoir levels, achieving a flow rate of 3.2 million liters per hour. These efforts aimed to relieve pressure on the structure while regulating outflow to the Jaguari River. By late September, the situation was downgraded from an emergency to an alert level. As the risk stabilized, 185 residents were authorized to return to their homes. While access to the dam remains restricted for ongoing permanent repairs, the immediate threat of collapse has subsided. ## Timeline ### 2026-09-27: São Luiz dam in São Marcos downgraded from emergency to alert The São Luiz dam in São Marcos, Brazil, has moved from emergency to alert status. Residents are returning home after technical teams stabilized structural fissures and lowered water levels. 5 sources. https://clstr.news/cluster/so-luiz-dam-in-so-marcos-downgraded-from-emergency-to-alert ### 2026-09-22: Arroio São Luiz dam collapse risk triggers evacuations in São Marcos A red alert has been issued for the Arroio São Luiz dam in São Marcos, Brazil, due to structural cracks. Approximately 170 residents have been evacuated as authorities work to reduce water levels. 35 sources. https://clstr.news/cluster/rio-branco-addresses-waste-accumulation-and-environmental-damage --- Cite as: Arroio São Luiz dam emergency in São Marcos. CLSTR, https://clstr.news/situations/arroio-so-luiz-dam-emergency-in-so-marcos