3 Study Area: The Backbarrier Tidal Flats of
Spiekeroog
3.1
Description of the Spiekeroog Backbarrier System
Andreas Hild
The Wadden Sea of the southern North Sea covers an area of about 9.300 km
2
and
represents one of the largest intertidal regions on earth (Fig. 3.1.1). Between Den
Helder and the Jade Bay (near Wilhelmshaven), the West and East Frisian Wadden
Sea forms a classical barrier island chain (Backhaus 1943). The island Spiekeroog
is located in the eastern part of this chain. Its backbarrier system, the main research
area of ELA W A T, is connected to the North Sea via the Otzumer Balje
(Fig. 3.1.2), a tidal inlet which separates Spiekeroog from the neighbouring island
Langeoog in the west. Referring to mean tide high water (MThw), the tidal basin
of the Otzumer Balje covers an area of about 73.5 km
2
(Walther 1972). The basin
is bordered by two watersheds: In the west by the Langeooger Plate, in the east by
the Hohe Bank. The distance between the island and the mainland averages 6.5 km
and the island has a length of approx. \0 km. The intertidal section of the Spiekeroog backbarrier system covers about 80 % of the area and is comparable to that of
other East Frisian tidal basins. The North Frisian and the Danish Wadden Sea have
about 70 % tidal flats on average, but the Sylt-R0m0-bight comprises only 30 %
intertidal areas (Reise & Riethmuller 1998). With an average tidal range of 2.7 m
at the western end of Spiekeroog island and of 2.9 m in the front of the mainland,
mesotidal conditions prevail in this backbarrier system (Niemeyer & Kaiser 1994).
At standard sea level (NN) the water volume in the catchment area amounts to
0.112 km'. The volume of water that is exchanged during a tidal cycle via the
Otzumer Balje is calculated to be 0.292 km' on average (Chap. 3.3).
The whole area is located in the "Wadden Sea National Park of Lower Saxony".
This National Park, which has been established in 1986 distinguishes three zones
with different degrees of protection. Large parts of Spiekeroog and the backbarrier
area fall into the highest protection category zone I (quiet zone) and 2 (intermediate zone), where an economic use is not allowed or only with restrictions. The
regulations are determined by the National Park decree.
The majority of the investigations were carried out in two sub-areas of the
backbarrier system: the Swinn- and the Groninger Plate (Fig. 3.1.2). The most
important sampling points, which are referred to in later chapters, are indicated in
Figs. 3.1.3 and 3.1.4 and listed in Table 3.1.1.
Spiekeroog
3.1
Description of the Spiekeroog Backbarrier System
Andreas Hild
The Wadden Sea of the southern North Sea covers an area of about 9.300 km
2
and
represents one of the largest intertidal regions on earth (Fig. 3.1.1). Between Den
Helder and the Jade Bay (near Wilhelmshaven), the West and East Frisian Wadden
Sea forms a classical barrier island chain (Backhaus 1943). The island Spiekeroog
is located in the eastern part of this chain. Its backbarrier system, the main research
area of ELA W A T, is connected to the North Sea via the Otzumer Balje
(Fig. 3.1.2), a tidal inlet which separates Spiekeroog from the neighbouring island
Langeoog in the west. Referring to mean tide high water (MThw), the tidal basin
of the Otzumer Balje covers an area of about 73.5 km
2
(Walther 1972). The basin
is bordered by two watersheds: In the west by the Langeooger Plate, in the east by
the Hohe Bank. The distance between the island and the mainland averages 6.5 km
and the island has a length of approx. \0 km. The intertidal section of the Spiekeroog backbarrier system covers about 80 % of the area and is comparable to that of
other East Frisian tidal basins. The North Frisian and the Danish Wadden Sea have
about 70 % tidal flats on average, but the Sylt-R0m0-bight comprises only 30 %
intertidal areas (Reise & Riethmuller 1998). With an average tidal range of 2.7 m
at the western end of Spiekeroog island and of 2.9 m in the front of the mainland,
mesotidal conditions prevail in this backbarrier system (Niemeyer & Kaiser 1994).
At standard sea level (NN) the water volume in the catchment area amounts to
0.112 km'. The volume of water that is exchanged during a tidal cycle via the
Otzumer Balje is calculated to be 0.292 km' on average (Chap. 3.3).
The whole area is located in the "Wadden Sea National Park of Lower Saxony".
This National Park, which has been established in 1986 distinguishes three zones
with different degrees of protection. Large parts of Spiekeroog and the backbarrier
area fall into the highest protection category zone I (quiet zone) and 2 (intermediate zone), where an economic use is not allowed or only with restrictions. The
regulations are determined by the National Park decree.
The majority of the investigations were carried out in two sub-areas of the
backbarrier system: the Swinn- and the Groninger Plate (Fig. 3.1.2). The most
important sampling points, which are referred to in later chapters, are indicated in
Figs. 3.1.3 and 3.1.4 and listed in Table 3.1.1.