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The Interreg IVB North Sea Region Programme

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Zonation of the TIDE estuaries


by Lindsay Geerts, Kirsten Wolfstein, Sander Jacobs, Stefan van Damme & Wouter Vandenbruwaene

3c. 2c. Zonation per estuary - Weser

There are five common (administrative) zonation schemes for the Weser estuary. The zonation of the Weser estuary includes four different levels; the zonation schemes according to WFD and BHD are both assigned to level 3 (fig. 5).

Level 1 includes the entire estuary from downstream of the weir Hemelingen (TIDE-km 0) where the tidal influence is stopped to the seaward border of the outer Weser estuary (TIDE-km 134, see level 2). The border of the outer Weser corresponds with the seaward border of the euhaline zone mentioned under level 4 (see also figure 5).

Level 2 is based on a common zonation scheme drawing a distinction between the lower Weser estuary (TIDE-km 0-69) and the outer Weser estuary (TIDE-km 69-134).

Level 3 includes the zonation schemes deduced according to WFD and BHD. Both comprise three zones. The zone borders according to the both directives differ slightly from each other and from the other zonation levels.

Level 4 consists of five different salinity zones defined according to the Venice system. The salinity zone borders correspond with level 1 and level 2. Figure 5 shows the geographical position of the five salinity zones along the Weser estuary. This zonation scheme was inter alia used for the recent fairway deepening.

A detailed description of the underlying parameters for the zonation is given in table 4 and 5. The basic characteristics of the Weser zones at level 4 are hydrological and morphological characteristics, the average salinity distribution according to the Venice system and the influence of tributaries and anabranches.

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Important to know

Reports / Measures / Tools

Tool: Zonation of the TIDE estuaries (Recommendation)

Management issues

What is important in establishing a zonation for estuaries?


SalinityVenice-systemZonation approach