• Association of waterboard
„Ammerländer Wasseracht“
• Relocation of a dyke at
‚Aper Tief‘ river
Flood protection – Nature conservation
Ammerländer Wasseracht
Civil Engineer Richard Eckhoff, Ammerländer Wasseracht, Germany
Ammerländer Wasseracht
Association
Water and soil
board
Water flow
and
Landscape
management
Association
Water and soil board
Landschaftspflegeverband
Ammerländer Wasseracht
Ammerländer Wasseracht
Area: approx. 620 km² = 239 squaremiles
Duties, responsibilities:
water-conversation, guarantee of water-drain
in waters, ditches of 583 km II. category
435 km III. category
construction of watersources, near natural
construction
maintenance of areas, watercourses to protect
ecosystems, soil and landscape conservation
18 pumping stations
Barrages and weirs
Handling by own machines, employees and workers
Ammerländer Wasseracht
Water- and
soil board
Water flow
and
Landscape
management
Main Tasks: - Maintenance of waters of 585 km II. category
493 km III. category
- Construction of
waterways
- near natural construction
of waterways
Ammerländer Wasseracht
Water- and soil
board
Water flow
and
Landscape
management
Members of the Ammerländer Wasseracht
approx. 30.000 members
thereof approx. 21.000 minimum payer
(association fee 18,50 €/unit/year,
in summary approx. 390.000,00 €/year)
Agricultural and foresty area
approx. 55.300 ha (association fee 18,50 €/hectare
approx. 1,05 Mio. €)
urban association fee approx. 0,51 Mio. €
Ammerländer Wasseracht
Rearrangement of a sufficient flood protection
Creation of additional reservoirs, polders
Development of nature protection area Aper Tief
Rearrangement of a water flood plain
Townplanning development of community Apen
Encouragement of recreation
Observing nature development
Motivations,
aims of project
Relocation of a dyke at
‚Aper Tief‘ river
Flood protection – Nature conservation
The planning area is influenced by tides and is
drained artificially
The north and south catchment were drained by
one pumping station south of Aper Tief river
Ammerländer
Wasseracht
Existing
circumstances
Capacity of the old
pumping station:
1,0 m³/s
Area influenced by tides
Water level of Aper Tief:
mean tide level high: + 1,12 mNN
mean tide level low: + 0,30 mNN
Heights of ground level
lowest ground level: + 0,70 mNN
highest ground level: + 2,40 mNN
Aerial Photograph of Aper Tief river and of villages Apen, Augustfehn, Hengstforde,2008
River Aper Tief
Village Augustfehn Village Hengstforde Village Apen
Nature reserve
Flora
18,1 ha 3,3 ha 4,8 ha 5,8 ha 7,4 ha 7,9 ha 0,6 ha
9,5 ha -
1,4 ha 0,6 ha
- 30,0 ha 13,6 ha
Watercourse (FF\FZ River mud flat (FW) Ponds, lakes (SE\SR\SX) Redd, cane (NRG) Pionier vegetation (NP) Intensiv meadow (GI) Mesophiles meadow (GM)
2006 2004 Habitats
Changes of habitats
2004
2009
Ammerländer Wasseracht
Fauna Ammerländer Wasseracht
Bekassine
Entwicklung des Brutvogelbestandes (Arten)
12
23
38
0
5
10
15
20
25
30
35
40
Vorher-Zustand 1 Jahr nachher 4 Jahre nachher
Art
en
zah
l
Brutvogelbestand
gefährdete Arten
number of species of breeding birdsl
Tripled
endangered species from 5 up to 15
amount of breeding birds doubled
degree of fulfillment (UQZ)
breeding birds 2004: 20 % 2009: 63 %
fish 2006: 65 % 2009: 94 %
beetle/bugs high, dynamic, 32 equal species
12 species disappear
20 species new appear
dragonfly species from 14 up to 18
Gefleckte Heidelibelle
Changes 2005 – 2009:
increasing soil wetness
Sedimentation and erosion by tide influence
➨ change to swamp/wet land
Uprising groundwaterlevel from 90 cm below
surface in 2006 to 50 cm in 2009
Sediment of mudflat, stream sediment up to 10
cm in 5 years
appearance of fresh-water mudflat, a rare biotop
in north-west Germany
fresh-water
mudflat
Ammerländer Wasseracht Soil