70
5 Challenges: Sectoral Descriptions
but the publication of Brahms (1754) might be seen as one point of change, especially in
Germany. The transition went differently in The Netherlands and in northern Germany, but
was triggered by storm surges in 1953 (The Netherlands and the UK) and 1962 (Germany).
Although the strategies have been revised, the way of doing so was different. Nevertheless,
both approaches led to a similar result: the best possible protection of people and their
assets against flooding at the coast. In general, the dikes were heightened and strengthened
by the available techniques based on sophisticated models and methods to determine the
height of future water levels.
5.1.4 Delineation of the Dutch Approach
The severe impacts of the storm surge in winter 1953 were a shock for all Dutch inhabitants. This event also caused severe impacts in the UK, for example, DCCF (1955),
4 but
in The Netherlands approximately 1900 people lost their lives. Several dike failures led to
enormous floodings – see, for example, Slager (1992); TAW (1998) and Seijffert (2001).
A detailed description on how the safety standards were found and how the different Delta
Commissions have worked in The Netherlands (Delta Commission I (1953–1960), Delta
Commission II (1975–1977), Committee Boertien I (1992), Committee Boertien II (1993)
and Delta Commission 2008) can be found in, for example, Yska (2009) and Voorendt
(2015).
As a reaction to the disaster in 1953 the coastal protection strategy was totally reworked for The Netherlands (TAW, 1998). A master plan to increase the safety of the
low-lying areas was established in the 1960s. The basis was the Flood Defense Act (FDA)
established in 1953. Up until the 1950s the risk of flooding was estimated on the basis of
intuition and experiences, as (complex) simulations or calculations to determine the risk of
flooding were not possible. The first step of the advisory board of the Delta Commission
was to investigate whether the water level of the 1953 flood (NAP
5 +3.85 m, Hoek van Holland) could be exceeded and the second step was to investigate the costs of increasing the
safety level in comparison with the expected economic benefits (e.g., van Danzig, 1956;
TAW, 1998, 2000). Based on the consideration of several uncertainties for the design of
protective elements the Delta Commission I decided for NAP +5 m in Hoek van Holland
as starting point for safety standards – see, for example, Peerbolte (1993). The result was
the classification of the Dutch coastline and the rivers into four safety levels (see Fig. 5.6),
6
that is, ranging from 1 to 10,000 for highly populated areas with high economic values to
1 to 4000 at the Westerschelde estuary and the north-east of The Netherlands, and 1 to
1250 at the rivers – see, for example, Delta Commission (1961) and TAW (2000). The
proposed coastal works, called “Delta Works”, were largely completed in the late 1980s.
4 Further information: www.metoffice.gov.uk/news/in-depth/1953-east-coast-flood
5 Normaal Amsterdam Peil = Amsterdam Ordnance Datum.
6 The safety levels are exemplified by the risk of failure of the protection infrastructure by over
topping.
5 Challenges: Sectoral Descriptions
but the publication of Brahms (1754) might be seen as one point of change, especially in
Germany. The transition went differently in The Netherlands and in northern Germany, but
was triggered by storm surges in 1953 (The Netherlands and the UK) and 1962 (Germany).
Although the strategies have been revised, the way of doing so was different. Nevertheless,
both approaches led to a similar result: the best possible protection of people and their
assets against flooding at the coast. In general, the dikes were heightened and strengthened
by the available techniques based on sophisticated models and methods to determine the
height of future water levels.
5.1.4 Delineation of the Dutch Approach
The severe impacts of the storm surge in winter 1953 were a shock for all Dutch inhabitants. This event also caused severe impacts in the UK, for example, DCCF (1955),
4 but
in The Netherlands approximately 1900 people lost their lives. Several dike failures led to
enormous floodings – see, for example, Slager (1992); TAW (1998) and Seijffert (2001).
A detailed description on how the safety standards were found and how the different Delta
Commissions have worked in The Netherlands (Delta Commission I (1953–1960), Delta
Commission II (1975–1977), Committee Boertien I (1992), Committee Boertien II (1993)
and Delta Commission 2008) can be found in, for example, Yska (2009) and Voorendt
(2015).
As a reaction to the disaster in 1953 the coastal protection strategy was totally reworked for The Netherlands (TAW, 1998). A master plan to increase the safety of the
low-lying areas was established in the 1960s. The basis was the Flood Defense Act (FDA)
established in 1953. Up until the 1950s the risk of flooding was estimated on the basis of
intuition and experiences, as (complex) simulations or calculations to determine the risk of
flooding were not possible. The first step of the advisory board of the Delta Commission
was to investigate whether the water level of the 1953 flood (NAP
5 +3.85 m, Hoek van Holland) could be exceeded and the second step was to investigate the costs of increasing the
safety level in comparison with the expected economic benefits (e.g., van Danzig, 1956;
TAW, 1998, 2000). Based on the consideration of several uncertainties for the design of
protective elements the Delta Commission I decided for NAP +5 m in Hoek van Holland
as starting point for safety standards – see, for example, Peerbolte (1993). The result was
the classification of the Dutch coastline and the rivers into four safety levels (see Fig. 5.6),
6
that is, ranging from 1 to 10,000 for highly populated areas with high economic values to
1 to 4000 at the Westerschelde estuary and the north-east of The Netherlands, and 1 to
1250 at the rivers – see, for example, Delta Commission (1961) and TAW (2000). The
proposed coastal works, called “Delta Works”, were largely completed in the late 1980s.
4 Further information: www.metoffice.gov.uk/news/in-depth/1953-east-coast-flood
5 Normaal Amsterdam Peil = Amsterdam Ordnance Datum.
6 The safety levels are exemplified by the risk of failure of the protection infrastructure by over
topping.