Polder Holter Hammrich

53.192777777778 7.5744444444444Coordinates: 53 ° 11 ′ 34 " N , 7 ° 34 ′ 28" E

Polder Holter Hammrich (view from the inlet and outlet structure in the east of the polder)

The Holter Hammrich polder is a relief polder in the Lower Saxony municipalities of Rhauderfehn and Ostrhauderfehn and the municipality of Detern in the joint municipality of Jümme in the district of Leer .

The polder is located in the Leda-Jümmeniederung in the district of Leer directly south of the Leda at the confluence of the main Fehn Canal. In the west it borders on the Holter Sieltief.

Most of the approximately 240 hectare polder is in the municipality of Rhauderfehn. A small part in the northwest of the polder lies in the municipality of Detern, another small part in the southeast in the municipality of Ostrhauderfehn. The storage volume of the polder is around 3.8 million m³. Construction of the polder began in September 2008. The official commissioning took place on May 30, 2011. The polder was flooded for the first time in January 2012.

For the polder, 3.1 km of new dykes were built along the Holter Sieltiefs, the Wersenweg and further to the existing dike of the Hauptfehnkanal, and a further 800 meters of dykes were reinforced. Most of the soil for the construction of the dykes was taken from the later polder, which later resulted in still waters .

The Polder Holter Hammrich is divided into two parts, the two areas are separated by the Heuweg. The western, 143 hectare sub-area "Leyßer Hammrich" was designed as a habitat for meadow birds. Except for a pond that was already there before the redesign, it is extensively managed as grassland. Most of the area is flooded in winter and spring by a controlled increase in the water level. In this way, a cultural landscape is to emerge as it was widespread in the Leda-Jümme area before the intensification of agriculture until the early 1950s. The eastern, 80 hectare sub-area "Altes Tief" is not cultivated. A diverse mosaic of shallow water zones , trees, reeds and wet grassland was created here. The approximately 1.4 km long polder canal was created in this sub-area. The vegetation is left to develop naturally.

There is an overflow weir between the two sub-areas so that different water levels can be set in them. There are pumps at four points along the dyke leading to the Leda so that water can be added during dry periods. Another three adjustable pipe outlets are to the Holter Sieltief in the west, another to the Urender Schloot in the south of the polder.

The inlet and outlet structure is located in the east of the polder at the confluence of the main canal with the Leda in the dike between Leda and the polder canal. It has two gates, each seven meters wide, through which up to 130 m³ of water can flow per second.

The polder is located in an extensive marshland . It is characterized by grassland on damp to wet locations and thus a habitat for numerous waders and meadow birds . Here come u. a. Lapwing , black godwit , redshank , curlew , common snipe and avocet as breeding birds , but also songbirds such as meadow pipit , skylark , black and bluethroat , pond warbler and marsh warbler , reed bunting , various ducks and geese and other birds. More than 60 species were documented in breeding bird surveys between 2008 and 2010.

The polder also has an important function as a feeding habitat and resting or wintering area for migratory birds. Over 40 species were documented in guest bird surveys.

Amphibians also benefit from the still waters. In the long term, the otters should also return to the area.

The polder can be circled on a 7 km long circular path, which partly runs on the dike. From the dike of Leda and the main canal, the area is often clearly visible. At the Holter pumping station between Holter Sieltief and Leda and at the inlet and outlet structure at the confluence of the main canal into the Leda, there are elevated viewpoints. In the south of the polder on the dike at the Alten Tief there is a screen wall with information boards, from which the area of the Alten Tief can be viewed through slits.

Web links

Commons : Polder Holter Hammrich - Collection of pictures, videos and audio files

Polder Holter Hammrich , Lower Saxony State Office for Water Management, Coastal Protection and Nature Protection (flood protection)
Model project "Holter Hammrich" , Lower Saxony State Agency for Water Management, Coastal and Nature Conservation (Biotope Protection)
Information leaflet on Polder Holter Hammrich (PDF; 2.1 MB), Lower Saxony State Agency for Water Management, Coastal and Nature Conservation
Experience nature in the Polder Holter Hammrich (PDF; 2.1 MB), experience nature in Lower Saxony
Development concept Holter Hammrich , map of the Leda-Jümme-Verband

Individual evidence

↑ ^a ^b “Holter Hammrich” model project - brief description , Lower Saxony State Agency for Water Management, Coastal Protection and Nature Conservation . Retrieved June 21, 2012.
↑ Model project "Holter Hammrich" - location in the area , Lower Saxony State Office for Water Management, Coastal Protection and Nature Conservation. Retrieved June 21, 2012.
^ Polder Holter Hammrich , Lower Saxony State Agency for Water Management, Coastal Protection and Nature Conservation. Retrieved June 21, 2012.
^ ^A ^b Elke Wieking, Ole Cordsen, Philipp Koenen: Hinterland under! , Ostfriesen-Zeitung , January 6, 2012. Retrieved June 21, 2012.
↑ ^a ^b ^c model project "Holter Hammrich" - nature conservation concept , Lower Saxony State Agency for Water Management, Coastal and Nature Conservation. Retrieved June 21, 2012.
↑ Polder Holter Hammrich , Natural Objects of the Month, District of Leer. Retrieved May 8, 2019.
↑ Holter Hammrich , Working Group Feuchtwiesenschutz Westniedersachsen e. V. Accessed June 21, 2012.
^ Breeding bird registration , Lower Saxony State Agency for Water Management, Coastal Protection and Nature Conservation (PDF, 251 kB). Retrieved June 21, 2012.
↑ Recording of guest birds , Lower Saxony State Agency for Water Management, Coastal Protection and Nature Conservation (PDF, 124 kB). Retrieved June 21, 2012.
↑ Model project “Holter Hammrich” - visitor concept , Lower Saxony State Office for Water Management, Coastal Protection and Nature Conservation. Retrieved June 21, 2012.

[kurz-1] “Holter Hammrich” model project - brief description , Lower Saxony State Agency for Water Management, Coastal Protection and Nature Conservation . Retrieved June 21, 2012.

[2] Model project "Holter Hammrich" - location in the area , Lower Saxony State Office for Water Management, Coastal Protection and Nature Conservation. Retrieved June 21, 2012.

[Polder-3] Polder Holter Hammrich , Lower Saxony State Agency for Water Management, Coastal Protection and Nature Conservation. Retrieved June 21, 2012.

[OZ-120106-4] A ^b Elke Wieking, Ole Cordsen, Philipp Koenen: Hinterland under! , Ostfriesen-Zeitung , January 6, 2012. Retrieved June 21, 2012.

[Natur-5] model project "Holter Hammrich" - nature conservation concept , Lower Saxony State Agency for Water Management, Coastal and Nature Conservation. Retrieved June 21, 2012.

[6] Polder Holter Hammrich , Natural Objects of the Month, District of Leer. Retrieved May 8, 2019.

[7] Holter Hammrich , Working Group Feuchtwiesenschutz Westniedersachsen e. V. Accessed June 21, 2012.

[8] Breeding bird registration , Lower Saxony State Agency for Water Management, Coastal Protection and Nature Conservation (PDF, 251 kB). Retrieved June 21, 2012.

[9] Recording of guest birds , Lower Saxony State Agency for Water Management, Coastal Protection and Nature Conservation (PDF, 124 kB). Retrieved June 21, 2012.

[10] Model project “Holter Hammrich” - visitor concept , Lower Saxony State Office for Water Management, Coastal Protection and Nature Conservation. Retrieved June 21, 2012.