The influence of compartmentalisation on flooding in Central Holland
MSc Thesis Appendices
A Selection of project area iii B History of land reclamation ix C Simulation results overview xi D Roughness coefficients lv E Excursions lvii F Assumptions lxix
E.P. de Bruine
ii Compartmentalisation Central Holland: Appendices
Appendix A Selection of project area
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Several dike-ring areas are available as a study area. Primary selection criteria are location (downstream, interaction between sea and river) and expected economic damage + casualties. Much information is gained from Rijkswaterstaat (2004b) and Klijn, Van der Klis, Stijnen and Kok (2004).
...... Figure A-1 Safety standard per dike-ring area. Source: meetkundige dienst.
iii Compartmentalisation Central Holland: Appendices
Downstream polder
This criterion limits the number of dike-ring areas available for this study considerable. If all dike-ring areas upstream of the ‘Land van Altena’ are left out, only 17 of the 56 dike-ring areas remain: numbers 14-34a (figure A-1)
Damage
Some downstream dike-ring areas contain large economic values. Especially Central Holland and IJsselmonde contain significant larger economic values than the other dike-ring areas. The damages are based on Rijkswaterstaat (2004b) Note that the damages are calculated by dividing the total expected damage by the kilometres of dike surrounding the area. In figure A-3, the damages to be prevented are shown for each dike-ring area.
...... Figure A-2 Dike ring Damage/km dike Damage/kilometre dike rates for downstream dike-ring areas. Number + description Million euros Source: Rijkswaterstaat (2004b) ...... 14 Central Holland 1000 17 IJsselmonde 590 29 Walcheren 230 20 Voorne-Putten 220 22 Eiland van Dordrecht 220 16 Alblasserwaard 220 32 Zeeuwsch Vlaanderen 190 19 Rosenburg 180 15 Lopik- en Krimpenerwaard 180 30 Zuid-Beveland west 120 34 West-Brabant 110
iv Compartmentalisation Central Holland: Appendices
...... Figure A-3 Damage/kilometre dike rates for all dike-ring areas. Source: Rijkswaterstaat (2004b)
v Compartmentalisation Central Holland: Appendices
Casualties
The number of casualties is also estimated in the same study of the RIVM. The results can be seen in the figure below. It can be noted that in Central Holland (14), IJsselmonde (17) and Alblasserwaard (16) a high number of casualties are expected. These areas are densely inhabited and have a low land level.
...... Figure A-4 Casualties in case of a flooding source: Rijkswaterstaat (2004b)
Interaction sea-river
For research purposes a sufficient large influence from sea and river is desirable. The influence of the river Scheldt is much smaller than the influence of the other two rivers on the estuary. For this reason, the South West islands of the province of Zeeland (dike-ring 28 till 33) are not chosen as a study area.
Selection
If the reasoning above is followed, a first selection of dike-ring areas can be made.
1. Dike-ring areas Central Holland (14), IJsselmonde (17) and Voorne-Putten (20) are considered the most interesting study areas. The influences of sea and river are expected to be present in sufficient amount. Damages and casualties due to a flooding event are predicted to be high. Central Holland and Voorne-Putten offer good possibilities for compartmen- talisation.
2. Dike-ring areas 22, 25 and 26 are second best: Dordrecht (22) is small, but has a high economic value and number of inhabitants. Goeree-Overflakkee (25) and Schouwen-Duiveland (26) are larger but contain lower economic values. vi Compartmentalisation Central Holland: Appendices
Selection
Central Holland is selected from the selection as study area. It has by far the most economic values to protect. The size and location of the area make i