Maciço Calcário Estremenho · about 2 km from Amiais de Baixo
Nascente do Alviela (Olhos de Água)
- Max depth215 m
- CertificationFull cave
- SpecialExperienced divers
Diving and fills
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The dive
A permanent karst spring west of Alcanena, in the south of the PNSAC.
Profile and sections
A permanent karst spring west of Alcanena, in the south of the PNSAC. The first dive was in 1961 (150 m, -35 m); a Franco-Portuguese team reached -130 m in 2004–2008, and since 2016 AESDA/XploraSub have explored further (-150 m in 2018, -215 m in 2020).
- Depth and profile
- Over 1250 m of underwater tunnels down to -215 m (AESDA/XploraSub, October 2020: the deepest cave dive in Portugal). You are soon deeper than -40 m, with long decompression.
- Configuration
- Exploration level: deep and long, with trimix and CCR or a lot of bailout (estimate).
- DPV: DPV possible (estimate)
- Long, deep passages: a scooter can help (estimate).
- Gas
- Trimix from 40 m
Who can dive where
- At least Full cave
- Configurations: Sidemount / CCR / Small cylinders / no-mount (speleo sumps)
- Configuration unknown — research beforehand
- Goes down to 215 m (trimix or deco may be needed)
- Experienced divers only
This is how the planner decides who in your team may dive this cave. Rules your own trip adds (organizer, a mail, the AI) show with your trip.
How to get there
PNSAC authorisation required. Only in the dry season: in the rainy season the strong current and flow make it virtually impossible to get in. The dry entrance is awkward and time-consuming: drops of 3 m and a tunnel 10 m long and 1.3 m high.
Around Nascente do Alviela (Olhos de Água)
FillsNo fill station known nearby
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