• 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