# Hydrological changes and flooding in Chile

> Live situation record from CLSTR: https://clstr.news/situations/hydrological-changes-and-flooding-in-chile
> Updated: 2026-10-05T09:58:08.000Z. Sources: 13. Developments: 2.

The Santa Juana Reservoir in Chile has reached its maximum storage capacity, necessitating water releases through its spillway. This release, alongside mountain snowmelt, has increased flows in the Huasco River, leading to alerts for Vallenar and Alto del Carmen.

In the Perales Viejos sector of Vallenar, an overflow affected five homes and a main road, leaving roughly 12 people isolated. While SENAPRED reported the situation in that sector has been controlled, authorities remain on alert for downstream areas. The General Directorate of Water (DGA) anticipates significant hydrological shifts, projecting that Huasco River volumes could exceed double the historical average between September 2026 and March 2027.

## Timeline

### 2026-10-05: Santa Juana Reservoir reaches capacity, increasing Huasco River flows

The Santa Juana Reservoir has reached capacity, causing increased flows in the Huasco River and flooding in Perales Viejos, Chile, amid seasonal snowmelt.

7 sources. https://clstr.news/cluster/santa-juana-reservoir-reaches-capacity-increasing-huasco-river-flows

### 2026-09-15: Water reservoirs in Chile and Spain face varying drought conditions

Reservoirs in Chile and Spain face different water security challenges: Chile's Puclaro Reservoir has recovered to 30% capacity, while Spain's Pontillón Reservoir faces a critical 20-day supply limit.

6 sources. https://clstr.news/cluster/water-reservoirs-in-chile-and-spain-face-varying-drought-conditions

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Cite as: Hydrological changes and flooding in Chile. CLSTR, https://clstr.news/situations/hydrological-changes-and-flooding-in-chile