Generalised hydrogeological map of Lower Saxony, 1 : 200 000 - Groundwater salinisation
(HUEK200GWVS)
The map shows groundwater salinisation at a scale of 1 : 200 000.
Fresh water aquifers are only encountered in Lower Saxony to maximum depths of 300 m. They are limited to regions in which the water is constantly replenished by infiltrating precipitation (active water exchange zone). Below this, increasingly salinised groundwater is observed (delayed water exchange zone). At greater depths this is underlain by a zone of predominantly stagnating groundwater.
The close relationship between freshwater reserves and active water exchange makes groundwater dynamics one of the central criteria when evaluating aquifer exploitability and for delineating groundwater bodies. The depth of the salinised water, i.e. the depth of active water exchange, is primarily controlled by the hydraulic properties of the strata involved and the potential of the percolated freshwater body. It can accordingly be highly variable.
In large watercourses (e.g. Elbe, Weser and Aller lowlands), where the hydrostatisc pressure is suddenly dissipated as a result of the movement of large volumes of groundwater into the watercourse, widespread pressure drops can occur, thus allowing infiltration of deep, salinised water into shallow aquifers (inland salinisation). The salinised deep groundwater zones are often associated with the Quaternary meltwater channels incised into the older subsurface. Here, the salinisation depth lies at a level where no aquifers exist outside of the channels. Furthermore, around 400 km² are classified as inland groundwater salinisation areas. They are caused by leaching processes acting on elevated salt domes (salt dome leaching, subrosion, cf. North German salt structures, 1 : 500 000, © BGR, 2008). As a result of the general rise in sea level along the North Sea coast following the last ice age, sea water entered inland aquifers on a broad front (coastal salinisation), thereby displacing the existing fresh water. A coastal strip 20 km deep, covering a total of 2,500 km², was impacted by this type of groundwater salinisation, making it predominantly useless for groundwater exploitation. Only on the coastal islands have fresh water lenses formed beneath the dunes as a result of infiltrating precipitation, allowing limited potable water production. In total, regions in Lower Saxony with an overall area of around 6,500 km² 2 are affected by groundwater salinisation, making groundwater exploitation either difficult or impossible.
To delineate the regions with salinised groundwater, the results of water analyses, geoeletric soundings and exploration wells with geophysical down-the-hole logging were evaluated. A body of water is referred to as salinised if the chloride content exceeds 250 mg/l, corresponding approximately to the human taste limit. In unconsolidated rock the map differentiates between completely salinised groundwater bodies or whether salt water was only encountered in part of the groundwater. In consolidated rock, only shallow salinisation is shown, including around salt spoil heaps
Informations about data
- Editing state:
Erfassung bzw. Erstellung der Daten ist abgeschlossen (completed).
- Date of last publication:
01.01.1987
- Information about data origin:
An Datengrundlagen sind eingegangen:
- Bohrungen der Bohrdatenbank Niedersachsen
- Wasseranalysen
- geoelektrische Sondierungen
- geopysikalische Bohrlochmessungen
- Karte zur Lage von Salzstöcken (BGR)
Ein Wasser wird als versalzt bezeichnet, wenn sein Chloridgehalt 250 mg/l übersteigt, was in etwa der menschlichen Geschmacksgrenze entspricht. In der Karte wird im Lockergestein unterschieden, ob der gesamte Grundwasserkörper versalzt ist oder ob Salzwasser nur in einem Teil des Grundwassers angetroffen wurde.
Contact person
Phone:
+49 (0)511-643-3613
Fax:
+49 (0)511-643-533613
Online access to data
To access the data online you can use the following applications/services:
Distribution information
Common informations (order proccess, product choise, prices):
Kostenfreier Download über den NIBIS-Kartenserver oder Kosten über den Datenvertrieb des LBEG entsprechend der Gebührenordnung
Data formats
- ArcGIS-Shapefile
(
Version:
unknown)
- JPEG
(
Version:
)
- PDF
(
Version:
unknown)
- TIFF
(
Version:
unknown)
Data medium
- DVD (dvd)
- CD-ROM (cdRom)
- Ausdruck (hardcopy)
Distribution contact
Phone:
+49 (0)511-643-3354
Fax:
+49 (0)511-643-533354
Additional information about the data
- Format of data:
digitale Karte in Raster- oder Vektorform (mapDigital)
- Topic:
Geowissenschaften
(geoscientificInformation)
- Key words:
NIBIS-Metadaten, opendata, inspireidentifiziert, opendata, sgd_Hydrogeologie
- Key words GEMET:
Geology
- Thesaurus name:
GEMET - INSPIRE themes, version 1.0
- Thesaurus date of puplication:
2008-06-01
- Geometry type:
Fläche (surface)
- Scale:
1:200000
- Coordinate system:
4647; ETRS89 / UTM zone 32N (zE-N)
(Europäisches Terrestrisches Referenzsystem von 1989 / Universale Transversale Mercatorabbildung Zone 32N)
- Altitude reference system:
DE_DHHN92_NH
- Reference layer:
Datenbestand (dataset )
- Language:
ger
- Character set:
utf8
Access- and security restrictions
- Security classification:
unbeschränkt (unclassified)
- Restriction of application:
Es gelten keine Zugriffsbeschränkungen.
Information about content (auto detected)
- Amount datasets/features:
250
- Spacial notation:
vector
- Eastern longitude:
6.5475
to
11.7416
- Northern latitude:
51.225
to
53.9343
About this data description
- Metadata standard:
Standard
ISO 19115
,
version
ISO 19115:2003/Cor. 1:2006 (E)
- Metadata status:
27.11.2024
- Metadata language:
ger
- Metadata character code:
utf8
Metadata contact