# Slapy Reservoir water level decline and species rescue

> Live situation record from CLSTR: https://clstr.news/situations/slapy-reservoir-water-level-decline-and-species-rescue
> Updated: 2026-10-22T04:22:00.000Z. Sources: 12. Developments: 4.

Extreme water shortages at the Slapy Reservoir in the Czech Republic have triggered large-scale rescue operations to protect aquatic life. To maintain water flow for Prague and other cities along the Vltava River, water managers have released water from the Orlík Reservoir, causing the Slapy water level to drop by nearly three meters, with daily decreases of ten to twenty centimeters.

In response, the Czech Union for Nature Conservation (ČSOP) has coordinated efforts to relocate endangered and native species, such as the protected painter’s mussel, to deeper waters. Volunteers have been instructed to focus on native species and avoid assisting invasive species. As of mid-October 2026, conservationists in coordination with Povodí Vltavy have successfully relocated more than 95,000 mussels, including rare species like the thick-shelled river mussel.

Despite recent rainfall, the water level remains low following a prolonged drought. The receding waters have recently exposed significant amounts of waste and debris on the reservoir floor and banks, including trash and car wrecks. To address this, the Vltava River Basin authority and the Czech Fishing Union have organized a large-scale cleanup event scheduled for October 28 to November 1.

Experts warn that these mussels are vital for filtering water and indicating environmental health. Because the task is too large for professional staff alone, organizers continue to call for public assistance through direct volunteer work and financial contributions to prevent mass die-offs.

## Timeline

### 2026-10-22: Slapy Reservoir water levels drop, exposing waste and debris

Drought and water level management at the Slapy Reservoir have exposed significant waste and debris, prompting a large-scale cleanup initiative and efforts to rescue rare mussels.

2 sources. https://clstr.news/cluster/slapy-reservoir-water-levels-drop-exposing-waste-and-debris

### 2026-10-13: Slapy Reservoir mussel rescue operation continues

Volunteers and conservationists are racing to save over 95,000 mussels stranded on the dry banks of the Slapy Reservoir in the Czech Republic following significant water level declines.

3 sources. https://clstr.news/cluster/slapy-reservoir-mussel-rescue-operation-continues

### 2026-10-05: Students rescue aquatic life at Slapská reservoir

Ecology students in the Czech Republic rescued hundreds of mussels and small fish trapped by low water levels at the Slapská reservoir during a coordinated environmental campaign.

2 sources. https://clstr.news/cluster/students-rescue-aquatic-life-at-slapsk-reservoir

### 2026-09-19: Slapy Reservoir rescue: Volunteers save mussels from drying waters

Volunteers are rescuing endangered mussels at the Slapy Reservoir in the Czech Republic after rapid water level drops caused by water management for the Vltava River left many aquatic animals stranded on dry's.

5 sources. https://clstr.news/cluster/slapy-reservoir-rescue-volunteers-save-mussels-from-drying-waters

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Cite as: Slapy Reservoir water level decline and species rescue. CLSTR, https://clstr.news/situations/slapy-reservoir-water-level-decline-and-species-rescue