Reservoir (artificial lake)11.3 km²Τεχνητή λίμνη Ιλαρίωνα

Ilarionas Reservoir

Ilarionas Reservoir is a reservoir (mapped as an artificial lake) with an area of 11.3 km² (OpenStreetMap). Its dam is Ilarionas Dam (130 m high, OpenStreetMap). It lies in the municipalities of Deskati, Servia and Grevena (regional units Grevena and Kozani, Western Macedonia). The nearest town with a page is Deskati, 6.9 km from the shore in a straight line.

Open on the map

What kind of water it is

The facts of the water body, with the source of each row.

Facts: Ilarionas Reservoir
Item	Value	Source
Kind	Reservoir (artificial lake)	OpenStreetMap
Area	11.3 km²	OpenStreetMap, worked out from the polygon
Dam	Ilarionas Dam	OpenStreetMap
Dam height	130 m	OpenStreetMap

The area of a reservoir changes with the water level; the table shows what OpenStreetMap maps, not the current level, the volume of water or the capacity.

Where it lies

Municipalities with at least 5 % of the Greek surface, by the municipal boundaries of OpenStreetMap.

Municipalities that hold the Greek surface
Municipality	Regional unit	Share of the Greek surface
Deskati	Grevena	71 %
Servia	Kozani	23 %
Grevena	Grevena	5 %

Official bathing-water sites

The official bathing-water register has no site that the European Environment Agency (EEA) classes as a lake site and that lies within 250 m of the shore of the reservoir. That does not mean swimming is allowed or forbidden, or that the water is clean or unfit; it only means there is no official classification here.

The beaches with an official water-quality classification are in the beach list; the method is explained at the end of the page.

All beaches with an official classification

Places nearby

Pages of this site, in a straight line and on the same side of the water, nearest first.

Towns and villages

Deskatitown, 6.9 km from the shore
Aianitown, 7.3 km from the shore
Kiposvillage, 10.7 km from the shore

Sights

Assumption of Mary Church, TornikiMonastery, on the shore
Zavordas MonasteryMonastery, on the shore
Aiani Archaeological MuseumMuseum, 7.9 km from the shore
Museum of the Macedonian Struggle, KozaniMuseum, 8.1 km from the shore

Peaks

Vounasapeak 1,580 m, 2.9 km from the shore
Kamvouniamountain 1,615 m, 8.7 km from the shore
Kissavosmountain 1,094 m, 10.0 km from the shore

Nearest airport

Kozani National AirportKZI, 33.8 km

Daylight

Sunrise and sunset at the point on the water that the map shows, for the 15th of each month, in Greek time (Europe/Athens). Calculated with the standard solar-geometry formula for a flat horizon; terrain around the water and cloud are not taken into account.

Daylight by month
Month	Day length	Sunrise	Sunset
January	9.6 h	07:52	17:30
February	10.7 h	07:27	18:07
March	11.9 h	06:46	18:38
April	13.2 h	06:56	20:09
May	14.3 h	06:18	20:39
June	15.0 h	06:03	21:02
July	14.8 h	06:15	21:01
August	13.8 h	06:43	20:31
September	12.5 h	07:12	19:43
October	11.2 h	07:41	18:55
November	10.0 h	07:17	17:18
December	9.3 h	07:47	17:08

Climate of the nearest settlement

This section is about Deskati, the nearest settlement with a page, not about the water itself. The water temperature of the reservoir is not in the open data we use.

Monthly averages for Deskati, not for the reservoir
Month	Mean temperature (°C)	Rain (mm)
January	2.1	53
February	3.6	49
March	7.1	51
April	11.3	42
May	16.8	48
June	22.2	37
July	25.5	30
August	25.2	28
September	19.8	55
October	14.1	66
November	8.6	62
December	3.5	70

NASA POWER (MERRA-2), period 2001–2020, model cell about 10 km from the settlement (a grid of about 50 km). Monthly averages from a regional model, not station readings and not a forecast.

How the numbers were counted

The water body, its outline and its name are OpenStreetMap's (ODbL, Geofabrik snapshot 24 Sep 2026, processed 9 Oct 2026). The area was worked out from the polygon, simplified to about 150 m, and is the area the map shows, not an official figure. A water body has a page when it has a name, an area of at least 2 km² in OpenStreetMap and at least 1 km² inside a Greek municipality.

The municipalities, the Greek part and the overlap with Natura 2000 sites come from a grid of about 10,000 points over the polygon's box: the points that fall inside the water and inside an OpenStreetMap municipal boundary or a YPEN (geoportal) Natura 2000 site are counted. The percentages are a sample, not an exact surface measurement.

The towns, beaches, sights and peaks of the "Places nearby" section are pages of this site. Distances are in a straight line from the nearest shore, not road kilometres, and a place is left out when sea lies between it and the water. A bathing site of the register counts as being on the lake when the EEA classes it as a lake site (the specialisedZoneType column of the classification table) and it lies within 250 m of the outline; of the register's sites that have a page on this site, the EEA classes only 2 as lake sites.

OpenStreetMap does not link this water body to a Wikidata item, so the page has no surface height, depth, inflows or outflow from there.

The dam comes from OpenStreetMap (the nearest named dam within 1,500 m of the shore), and its height from the OpenStreetMap height tag, which we have not checked.

Sources

Every figure on this page comes from the sources below, with the date each was updated.

OpenStreetMap: lakes, reservoirs, lagoons and damsOpenStreetMap contributors, via a Geofabrik snapshot · Geofabrik snapshot of 24 September 2026 · Date: 9 October 2026
Monthly climate normalsNASA POWER, MERRA-2 meteorological model · 2001–2020 climatology period returned by NASA POWER · Date: 24 September 2026
Designated bathing waters (locations)Ministry for Environment and Energy: YPEN geoportal · Current bathing season register · Date: 20 September 2026
Bathing water quality classificationEuropean Environment Agency: WISE Bathing Water Directive database · Latest assessed season in the EEA database; every season from 2011 is kept as a per-beach history · Date: 9 October 2026
This water body in OpenStreetMap (link only)OpenStreetMap contributors, ODbL

Page updated 7 October 2026.