Give us feedback


www.tide-project.eu

Project part-financed by the European Union (European Regional Development Fund)

The Interreg IVB North Sea Region Programme


Disclaimer:
The authors are solely responsible for the content of this report. Material included herein does not represent the opinion of the European Community, and the European Community is not responsible for any use that might be made of it.
Back to overview reports



Interestuarine comparison: Hydro-geomorphology

3d. Mouth definition

Within the TIDE project it was agreed to plot estuary characteristics along the length profile of the estuaries against the so called TIDE kilometers (i.e. the distance to an up-estuary boundary, for example a weir). This agreement was made to easily compare the results of the different TIDE work packages (hydro-geomorphology, ecology, measures,…). However, within the interestuarine comparison of this hydro-geomorphological study, it was found that the TIDE kilometers approach was not suitable and that the definition of “a mouth” was necessary to make a proper comparison between the different estuaries.

Different criteria (shape, tidal influence, river influence, geology, salinity) can be used to define the mouth of an estuary (e.g., Savenije, 2005). Within this study it was decided to define the mouth dependent on the research topics (for an overview of the research topics see §2). Two definitions for the mouth will be used in this study:
  • Mouth based on the width change (mouthgeo): once the width change at MHWL is below a certain threshold value, at that location the mouth area stops and the estuary starts (see Figure 8)
  • Mouth based on salinity (mouthsal): once the salinity of the summer salinity profile drops below 30 PSU, at that location the mouth area stops and the estuary starts
The definition based on the width change is for example necessary for research topic 1. There the effect of estuary funneling on the tidal amplification is studied. For research topic 3, saline intrusion plays an important role and there the mouth based on salinity is a more useful approach.
The relationship between the TIDE km’s, the distance to the mouthgeo, and the distance to the mouthsal is given in Table 6.



Table 6 – Relationship between the tide kilometers and kilometers to mouthgeo and mouthsal. For the Scheldt, the distance to Vlissingen is also provided
TIDE km Scheldt Elbe Weser Humber
Mouthgeo Mouthsal Vlissingen Mouthgeo Mouthsal Mouthgeo Mouthsal Mouthgeo Mouthsal
160 2 -7 0 -46 -11 -88 -58 -46 -51
150 12 3 10 -36 -1 -78 -48 -36 -41
140 22 13 20 -26 9 -68 -38 -26 -31
130 32 23 30 -16 19 -58 -28 -16 -21
120 42 33 40 -6 29 -48 -18 -6 -11
110 52 43 50 4 39 -38 -8 4 -1
100 62 53 60 14 49 -28 2 14 9
90 72 63 70 24 59 -18 12 24 19
80 82 73 80 34 69 -8 22 34 29
70 92 83 90 44 79 3 32 44 39
60 102 93 100 54 89 13 42 54 49
50 112 103 110 64 99 23 52 64 59
40 122 113 120 74 109 33 62 74 69
30 132 123 130 84 119 43 72 84 79
20 142 133 140 94 129 53 82 94 89
10 152 143 150 104 139 63 92 104 99
0 162 153 160 114 149 73 102 114 109


Back to top