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Drinking Water Directive - Water Supply Zones

Miroslav FANTA
By Miroslav FANTA Replies (3)

Our institution CENIA (Czech Environmental Information Agency) is responsible for coordination of INSPIRE acitivities in the Czech Republic.

Providers of DWD data in our country asked us for support concerning the preparation of Water Supply Zones layer for INSPIRE purposes. The Water Supply Zones are reported under Drinking Water Directive as "point objects" specified by their centroid coordinates. Can you provide some hints or recommendations how these zones should be created and classified for INSPIRE? (points or polygons? classification classes and their boundaries? representation of large agglomerations - one object for entire agglomeration or individual objects by city quarters? link to relevant water sources / water protection areas? etc.). 

The "Zone Type Code" parameter codelist here:  does not contain any item relevant for water supply zones. Out of available values in this codelist, which one should be used for water supply zones dataset?

I have checked availability of these data in INSPIRE geoportal here:

6 metadata items provided by NL, BE and LU are available, but in reality one of them represents water suply zones only: 

BE: Zones de distribution en eau potable

Spatial data theme of this dataset is "Area management / restriction / regulation zones & reporting units".

unfortunately, the appropriate map service does not work properly, it can be added to the map composition, but the data are not displayed. In the preview vindow, background map and legend are displayed only (according to this legend, water supply zones are represented by polygons - all objects by one color, i.e. in one class).

Thank you very much.


  • Stefania MORRONE

    By Stefania MORRONE

    Hi Miroslaw,

    the water supply zones are "areas managed" under the Drinking Water Directive and well fit the scope of the Area Management / restriction / regulation zones & reporting units INSPIRE data theme.

    Regarding the geometry representation, the AM Data Specification state that "Typically the representation of the geometry of a ManagementRestrictionOrRegulationZone shall be either a GM_Surface or GM_MultiSurface. However, it has been recognised that at some levels of detail the geometry may be represented as either a GM_Point or GM_Curve.Consequently, any constraints on the geometry representation have been removed".

    This means that point geometry can be used because in this case it corresponds to the level of detail of the source data set .

    Regarding the Zone Type code, the is the value to use.

    To further specify that the source data set contains water supply zones under the Drinking Water Directive, the specialisedZoneType attribute (optional attribute) could be used. In fact, this attribute is meant to provide an additional value to further specialise the type of zone specified in the zoneType element. 

    The specialisedZoneType can contain any value defined by data provider (as long as it is made available in a public register – ref. Article 6(3) of the Implementing Rules).

    More specifically, the does not contain any value (empty code list). The AM Data Specification state that the values for the specialisedZoneTypeshould be derived from relevant domain-specific controlled vocabulary, where available". An extension of the INSPIRE code list SpecialisedZoneTypeCode is provided in the Eionet Data Dictionary, but currently it does not contain any value for water supply zones under DWD (read more on the specialisedZoneTypeCode in this Thematic Cluster post.).

    Regarding the WMS layer,  follow what specified in Sec 11.1 of the Data Specification for the layer AM.DrinkingWaterProtectionArea and in Sec 11.2.7 for the style relevant to abovementioned layer (for points, the geometry is rendered  as a square with a size of 6 pixels, with a light blue(#BED2FF) fill and a black outline).

    Hope this helps



  • Miroslav FANTA

    By Miroslav FANTA

    Dear Stefania,

    thank you very much for your prompt reply.

    Concerning Zone Type Code attribute, using of suggested "drinkingWaterProtectionArea" codelist item could be considered as problematic from the first point of view, because meaning of the drinking water protection area (= area from which the drinking water is taken) is different from the water supply zone (= area supplied by drinking water). On the other hand, if appropriate clarification is provided in the specialisedZoneType attribute (for example: "water supply zone (DWD)") and if we consider, that no more suitable value is available in the ZoneType codelist, then suggested solution is OK.

    I have just one additional question (which could be relevant also for other Area management topics) - if polygon dataset is provided by country within this theme, is it allowed to use overlapping polygons?

    Example: agglomerations A, B and C are served by drinking water sources 1 and 2. Out of this, agglomeration A is served by source 1 only, agglomeration C is served by source 2 only and agglomeration B is served by water mixed from both sources 1 + 2. In such case, water supply zone relevant for drinking water source 1 includes agglomerations A + B and water supply zone relevant for drinking water source 2 includes agglomerations B + C. If the water supply zones are represented by polygons, these polygons will overlapp in the area of agglomeration B. Is such solution acceptable?


  • Stefania MORRONE

    By Stefania MORRONE

    Dear Miroslav,

    the solution is acceptable.



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