# Siwa Salt Oasis (DD-675)

> Siwa is an oasis town in Egypt's Matrouh Governorate, in a depression that reaches about 19 m below sea level. It lies about 50 km east of the Libyan border and 560 km from Cairo, and about 25,000-30,000 people live there. It has roughly 200 natural springs (one study counts 226) and several large salt lakes. Most springs draw on a shallow limestone aquifer, the Tertiary Carbonate Aquifer, which is moderately to highly saline. A 2026 study found that the shallow aquifer is recharged mainly by upward flow from the deep Nubian Sandstone Aquifer, whose 'fossil' paleowater is about 4,300 to 14,200 years old. Because Siwa is a closed basin, excess irrigation and drainage water has nowhere to go. The salt lakes grew from about 23 km² in 1990 to about 61 km² in 2020, and Egypt's water ministry calls waterlogging and salinity chronic problems. The vivid turquoise pools that visitors float in are very salty. The oasis was also home to the ancient oracle of Amun, which Alexander the Great visited.

- Department: Locations (also Nature)
- First published: 2025-11-29
- Last updated: 2025-11-29
- Permalink: https://detailenjoyer.com/case/siwa-salt-oasis/
- Author: Marcus Easterling (DetailEnjoyer), The Detail Department

## Quick facts

- **DD-675-F01**: Siwa has roughly 200 natural springs. _(Write-up · Exhibit B (Springs))_
- **DD-675-F02**: Siwa's salt lakes grew from about 23 km² in 1990 to about 61 km² in 2020. _(Write-up · Exhibit D (Growing salt lakes))_

## Write-up

Floating in the Sahara. Siwa's salty springs lie 50 km from the Libyan border.

1. **Where**: Siwa lies in a depression in Egypt's Western Desert, about 50 km east of the Libyan border and 560 km from Cairo. The depression reaches about 19 m below sea level.
2. **Springs**: There are roughly 200 natural springs. A 2015 soil-science study counted 226, tapping a shallow aquifer with moderate to high salinity, plus about 150 deeper wells with fresher water.
3. **Fossil water**: The deep Nubian Sandstone Aquifer holds paleowater about 4,300 to 14,200 years old. A 2026 study found it supplies most of the shallow aquifer's recharge through faults, so the springs are partly 'fossil' water.
4. **Growing salt lakes**: Siwa is a closed basin with no outlet, so irrigation drainage collects in its lakes. Salt-lake area grew from about 22.6 km² in 1990 to about 60.6 km² in 2020, and waterlogging has damaged farms and buildings.
5. **Management**: Egypt's water ministry has raised embankments around Lake Siwa, drilled deep wells to blend fresher water with saline water, and started building a 33.7 km canal to carry drainage water to a depression east of the oasis.

## Related case files

- [Water Table Troubles (DD-071)](https://detailenjoyer.com/case/water-table-troubles/): Another case about depleting groundwater
- [Danakil Depression (DD-055)](https://detailenjoyer.com/case/danakil-depression/): Another salt-crusted desert depression below sea level
- [The Red City (DD-198)](https://detailenjoyer.com/case/the-red-city/): I linked more from North Africa

## Reel vs. record

- **Health claims**: 'therapeutic qualities' is a tourism claim. I found no rigorous medical evidence for it, and this case gives no health advice.
- **Water source**: most springs discharge from a shallow, increasingly saline limestone aquifer. That aquifer is largely recharged by the deep Nubian Sandstone Aquifer, whose paleowater is about 4,300-14,200 years old (Hydrogeology Journal, 2026).
- **Count**: the oasis has about 200 springs. One study counts 226, so 'over 200' is reasonable but varies by source.
- **Missing problem**: Siwa is a closed basin, so excess drainage water has expanded the salt lakes from about 23 km² (1990) to about 61 km² (2020), causing waterlogging and soil salinization.
- **Not renewable**: the deep 'fossil' water is non-renewable, and modeling projects 30-40 m of drawdown by 2100 at current pumping rates (Hydrogeology Journal, 2026).

## Video: Siwa Salt Oasis: Floating in the Sahara

- Duration: 20.8 s · Published: 2025-11-29
- File: https://detailenjoyer.com/assets/videos/DRqoY9VjE_Y.mp4

### Transcript

DID YOU KNOW? The water in Siwa Oasis, Egypt, is famed for its high mineral content and therapeutic qualities, drawn from natural springs that have sustained the oasis for thousands of years. Located deep in Egypt's Western Desert, Siwa's water emerges from underground aquifers fed by ancient fossil water reserves, creating over 200 springs and salt lakes that shape the region's unique ecosystem. NOW YOU KNOW!

## Questions & answers

**Q: In which country is Siwa Oasis?**  
A: Egypt, about 50 km east of the Libyan border. _(Source: Write-up · Exhibit A (Where) · Wikipedia: Siwa Oasis)_

**Q: Roughly how many natural springs does Siwa have?**  
A: About 200. _(Source: Write-up · Exhibit B (Springs) · Wikipedia: Siwa Oasis; Egyptian Journal of Soil Science (2015): Assessment of drainage water quality in Siwa Oasis)_

**Q: Siwa's depression reaches about how far below sea level?**  
A: About 19 m below sea level. _(Source: Write-up · Exhibit A (Where) · Wikipedia: Siwa Oasis)_

**Q: Which deep aquifer holds Siwa's 'fossil' water?**  
A: The Nubian Sandstone Aquifer. _(Source: Write-up · Exhibit C (Fossil water) · Hydrogeology Journal (2026): Groundwater salinity sources and inter-aquifer mixing dynamics in Siwa Oasis, Egypt)_

**Q: Why have Siwa's salt lakes grown?**  
A: It's a closed basin, so irrigation drainage collects in the lakes. _(Source: Write-up · Exhibit D (Growing salt lakes) · ESS Open Archive preprint (2024): Sustainable development of the water resources in Siwa, Western Desert, Egypt; Egyptian Journal of Soil Science (2015): Assessment of drainage water quality in Siwa Oasis; Egypt Ministry of Water Resources and Irrigation: Siwa Oasis Development Project)_

## Sources

- [Wikipedia: Siwa Oasis](https://en.wikipedia.org/wiki/Siwa_Oasis)
- [Hydrogeology Journal (2026): Groundwater salinity sources and inter-aquifer mixing dynamics in Siwa Oasis, Egypt](https://doi.org/10.1007/s10040-026-03078-3)
- [Egyptian Journal of Soil Science (2015): Assessment of drainage water quality in Siwa Oasis](https://doi.org/10.21608/ejss.2015.1568)
- [ESS Open Archive preprint (2024): Sustainable development of the water resources in Siwa, Western Desert, Egypt](https://doi.org/10.22541/essoar.170542141.14906606/v1)
- [Egypt Ministry of Water Resources and Irrigation: Siwa Oasis Development Project](https://www.mwri.gov.eg/?lang=en&page_id=34022)

## Cite this case file

Easterling, Marcus. "Siwa Salt Oasis." The Detail Department (DetailEnjoyer), case file DD-675, last updated Nov 29, 2025. https://detailenjoyer.com/case/siwa-salt-oasis/