Editing Espoo (section)

=== Inland waters ===
There are over a hundred lakes and ponds in Espoo, of which 73 have an area of over a hectare.<ref name="paikkala"/>{{rp|5}}<ref name="jarviwiki">[http://www.jarviwiki.fi/wiki/Espoo Espoo] {{Webarchive|url=https://web.archive.org/web/20220927030711/https://www.jarviwiki.fi/wiki/Espoo |date=27 September 2022 }}, ''jarviwiki.fi''. Accessed on 9 September 2019.</ref> The lakes in Espoo were formed when the land slowly started rising after the continental ice sheet had thawed, and water started flowing into the crevices in the bedrock. The oldest lakes in Espoo are Kalatoin, Iso Majaslampi, Orajärvi and Pieni Majaslampi, all located over 80 metres above sea level. At that time, what is now the Baltic Sea was in a so-called [[Yoldia Sea]] phase, which had formed when the surface of the [[Baltic Ice Lake]] had lowered tens of metres in a short time. Nuuksio slowly expanded into part of the mainland and new lakes were formed when the sea level sank. Development stopped for about a millennium and a half when the ancient Baltic Sea changed into the [[Ancylus Lake]]. Its surface was originally about 60 metres above the current sea level. The Ancylus Lake formed into the salty [[Littorina Sea]] when the current [[Danish straits]] started opening up. The surface of the Littorina Sea was about 34 metres above the current sea level. At that time, almost all lakes in northern Espoo had been separated from the sea. Only the lake [[Nuuksion Pitkäjärvi]] remained as a narrow, [[fjord]]-like bay. The shore of the Littorina Sea remained at its place for a long time as upthrust slowed down. Rocky rims remain of the ancient sea shore on hills and cliffs. Nuuksion Pitkäjärvi only separated from the sea and became an inland lake about five millennia ago. About four millennia ago the land had risen so far that also [[Lake Bodom]], [[Lippajärvi]] and other pools in central Espoo changed from shallow bays into lakes.<ref name="paikkala"/>{{rp|15}}

Most of the lakes in Espoo are located to the north of the [[Finnish national road 1]], particularly in the lake highlands in Nuuksio. There are three pools named Pitkäjärvi ("long lake"): [[Pitkäjärvi]], Nuuksion Pitkäjärvi and [[Velskolan Pitkäjärvi]]. The largest lake in Espoo is [[Lake Bodom]] with a surface area of 4.1 square kilometres and an average depth of 4.3 metres.<ref name="järvien">[https://web.archive.org/web/20161028131718/http://www.espoo.fi/download/noname/%7BC89C4628-8F1E-4D99-B9E8-EC0D8657A3CD%7D/36868 Selvitys Espoon järvien tilasta], environmental centre of Uusimaa. Accessed on 9 November 2017.</ref>{{rp|50}} The largest depth of Nuuksion Pitkäjärvi is 18 metres and the average depth is 6.5 metres, and there are tens of lakes and ponds in its [[drainage basin]] of 60 square kilometres.<ref name="järvien"/>{{rp|37}} There are few lakes in southern Espoo. The shallow lake [[Hannusjärvi]] with a surface area of six hectares is located in [[Kaitaa]]<ref name="järvien"/>{{rp|53}} and the small lake [[Pentalanjärvi]] is located in the island of [[Pentala]].<ref name="järvien"/>{{rp|55}}

Because the sweet water pools to the south of the [[Salpausselkä]] ridges formed when the ancient bays separated from the sea into lakes because of upthrust, only very few islands developed in them.<ref name="paikkala"/>{{rp|15}} One of the few inland islands in Espoo is an island of fifteen hectares in the lake [[Saarijärvi, Espoo|Saarijärvi]] located near the border to Vihti. There was a suggestion to name the rocky island covered in pine forests as Partiosaari, but nothing became of this.<ref name="paikkala"/>{{rp|61}}

The differences in the surface heights of the lakes in Espoo are considerable. Lake Pieni Majaslampi is located the highest up, 97 metres above sea level. Lake Saarijärvi near it is located 25 metres lower. Because of the height differences, small rapids sometimes form in spring time in the creeks between adjacent water pools.<ref name="ahola">Ahola, Joel: ''Nuuksio: retkeilyopas & kartta''. Helsinki: Retkeilymedia Ahola ja Affecto Oy, 2008. {{ISBN|978-951-593-200-6}}.</ref>{{rp|50}}