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Reservoirs.EARTH
Spain
High

Alsa - Mediajo

Cantábrico Occidental

Capacity

22 hm³

Coordinates

0.000°N, 0.000°E

Operator

Cantábrico Occidental

86.4% full

Current fill

86.4%
High

vs 7 days ago

0.0%

stable

vs 1 year ago

0.0%

year-over-year

7-day trend

stable

Technical specifications

Total capacity22 hm³
Usable capacity22 hm³
Primary use
OperatorCantábrico Occidental
River basinCantábrico Occidental
Data source:embalses.net·Last reading: 2026-09-07

About Alsa - Mediajo

As of September 7, 2026, Alsa - Mediajo is filled to 86.4% of its total capacity, holding roughly 19 hm³ of water out of a maximum 22 hm³. At this level the reservoir is high.

Over the most recent week on record the fill level has held broadly steady (+0.0 pts), and it sits close to where it was a year earlier.

Across the readings we hold for Alsa - Mediajo — 419 data points between September 4, 2018 and September 7, 2026 — the level has ranged from a low of 63.6% (November 8, 2022) to a high of 104.5% (March 31, 2026). On average the reservoir is fullest around May and at its lowest around November.

It is operated by Cantábrico Occidental. It lies within the Cantábrico Occidental basin at 0.000°N, 0.000°E.

Key facts

Current fill level
86.4%
Water stored
19 hm³
Total capacity
22 hm³
7-day change
No change
Year-on-year
No change
River basin
Cantábrico Occidental
Operator
Cantábrico Occidental
Coordinates
0.000°N, 0.000°E
Last updated
September 7, 2026

Recent readings

DateFill levelVolume (hm³)
7 Sep 202686.4%19
1 Sep 202686.4%19
25 Aug 202690.9%20
18 Aug 202686.4%19
11 Aug 202686.4%19
4 Aug 202690.9%20
28 Jul 202690.9%20
21 Jul 202690.9%20
14 Jul 202695.5%21
7 Jul 2026100.0%22
30 Jun 2026100.0%22
23 Jun 2026100.0%22
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