Otterndorf pumping station
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The pumping station Otterndorf with its 483 square kilometer catchment area of the main performers in the drainage Hadeln , the Sietlandes , Bad Bederkesas and parts of Börde Lamstedt . Strictly speaking, since 1953 it has consisted of two pumping stations that are technically completely separate from each other, and for their operational safety a common emergency power generator has been available since 1996 .
Drainage area
The drainage area extends over the Bederkesa drainage association with its 29 municipalities and a catchment area of around 26,000 hectares. Small pumping stations transport the water from the tributaries to the height of the 25-kilometer-long Hadelner Canal , which leads it into the Elbe .
The other part of the drainage area comprises the approx. 22,000 hectare area of the Medemverband. This water is mainly brought in through the Medem . In this drainage area, two stage pumping stations were built around the same time as the Otterndorfer pumping station: One in Ihlienworth , where today five watercourses merge to form the Medem, and a second at Nordleda on the Wilster . The stepped pumping stations raise the water of the canals and small rivers so that it flows downhill to Otterndorf. In the southern part of the drainage area of the Ihlienworth pumping station, the control of floods remained difficult, so that in 1971 another pumping station went into operation near Steinau , which drains into the Hadelner Canal. With the construction of the third pumping station, the direction of flow in the upper reaches of the Medem (usually referred to as floodplain) was reversed.
prehistory
Before 1850, the entire land of Hadeln as well as the Bederkesa office and parts of Lamstedt were drained only by the Medem river. Especially the Hadler Sietland around Ihlienworth and Steinau , which is below sea level, had major problems with the water in the rainy months. Since the water also flowed from the Bederkesa office to the south into the deeper Sietland, severe floods often spoiled the harvests and thus repeatedly undermined the efforts of the Sietlanders for more yields.
The Hadelner Canal was built as a drainage canal around 1853 . The water flowed away faster through the new canal, but since the Sietland was still the lowest point, the water flowed away more slowly here than from the higher areas. Only when their drains were closed to prevent excessive drainage, the water of the Sietland could drain. When the low tide of the Lower Elbe was higher than the mean low tide when the tidal range was low , when the wind was unfavorable or when the Elbe flooded the river, the water from the Siethland could hardly flow away. The construction of the pumping station in 1928 improved this.
technology
Pumping station from 1928
Schütz (passive drainage) closed
because the pump from 1928 is working
The Otterndorf pumping station has the largest centrifugal pump in Europe. With a diameter of 4.40 m it is unsurpassed as a single pump in Europe (as of 2006). A well-known regional picture shows a rider in the 3.5 m high pipe through which the pumped water flows into the Elbe.
Operated by MAN diesel engines, the pumping station performed 24 cubic meters per second at a delivery height of 1.60 m. If the 18 t pump is switched on and runs at normal operating speed, the water level in the canal in front of the pumping station drops by 20 cm within minutes. Since the modernization in 1996, the old centrifugal pump of the "diesel pumping station" has been driven by two 400 kW electric motors. In order to be able to pump independently of the general electricity supply if necessary, an emergency power generator with a diesel engine was installed.
Electric pumping station
In the winter of 1950/1951 the pump of the diesel pumping station failed for several months, which is why the stage pumping stations had to stop operating. As a result of the lack of drainage, 80 square kilometers in Sietland were flooded up to 50 centimeters high. Therefore, in 1953, another pumping station was built next to the diesel pumping station, the building of which stands as a bridge over the associated drainage canal. Two pumps work here, driven by 500 kW electric motors . With a delivery height of 1.60 m, you can pump approx. 20 cubic meters of water per second (i.e. 20,000 l / s) through the Medem pumping station "lock" into the port of Otterndorf and thus into the Elbe.
Locks
Until 1854 there had been three sluices next to each other at the mouth of the Medem, locally all called “sluices”. They were inadequate for both flood protection and drainage.
Canal lock
The Hadelner Canal , built between 1852 and 1854 , got its own lock some 400 m further east. From 1854 it was designed as a tunnel vault lock with a pair of mitred gates and was 36 m long and 6.1 m wide. Since the experts expected an enormous increase in the volume of goods traffic, the lock was expanded in 1968. In the spacious lock chamber behind the dyke, three Kümos with a length of 57 m, a width of 5.2 m and a draft of 1.5 m can be locked at the same time. In principle, small vehicles can also be funneled into the small chamber in the dike's culvert. Since it doesn’t bring any relief for the lock keeper and skippers can easily panic in the darkness of the Siel, this is rarely done. In 1985 the lock was completely renovated and a hydraulically driven lifting gate was installed for the second dike safety .
Medem lock
The three wooden locks at the mouth of the Medem were only replaced by a lock that was state-of-the-art at the time in 1861–1864. It was built on the site of the old central lock. The passages of the other two locks were sealed. In 1993/1994 the lock was replaced by a new building. The lock chamber is hidden in the dike body, but receives daylight through a window.
Medem pumping station "sluice"
The 1928 diesel pumping station was built near the east of the three locks from before 1854, using their water connections. The channel of the electric pumping station from 1952/1954 was laid directly next to that of the diesel pumping station. Both pumping stations are behind the dike and pump into what is, however, a very small grinding bosom from which the water flows through a sluice, the so-called “pumping station sluice”, into the outer medem and thus into the Lower Elbe. The current sewer system "Schöpfwerkschleuse" is a new building as a replacement from 1995/96. This passage through the dike is not designed for vehicles. As long as the pumping stations are pumping, a contactor closes the outlet of the central channel of the pumping station so that no water flows back into the Medem. If the water level outside the dike is low, passive drainage is also possible here by opening the contactor.
Cross connection
Since 1956, just behind the dike, a narrow canal, the so-called piercing, has connected the Hadelner Canal with the Medem, so that the pumping station can also drain the canal. Its inlet is, however, divided by a longitudinal wall; the old pumping station primarily drains the canal, the new pumping station primarily the Medem.
Dike security
The canal lock is currently a weak point in the dike line, as the height has not yet been adjusted to the current dike profile. A completely new building is planned and will completely replace the old lock. The planning was almost complete and the start of construction was planned for the end of 2013. A recalculation of the costs in 2013 resulted in a value of 50 million euros, compared to an estimated 28 million euros until then. For this reason, planning was postponed for the time being and other cheaper options are to be examined. In the area of the Hadelner canal lock, the main dike has an understick of up to one meter. The construction of the Hadelner canal lock is therefore an urgent coastal protection measure to achieve the desired level of coastal protection.
Otterndorf lock of the Hadelner Canal, gateway to the Elbe
Otterndorf lock of the Hadelner Canal, gateway to the canal
Inside of the Medem lock
guides
It is possible to organize guided tours by staff at the Otterndorf tourist information office.
Web links
Individual evidence
- ↑ a b Gerhard Großkopf: Coastal protection and internal drainage between the Weser and Elbe. In: Johann Kramer, Hans Rohde (edit.): Historical coastal protection. Dyke construction, island protection and inland drainage on the North and Baltic Seas. Konrad Wittwer, Stuttgart 1992, ISBN 3-87919-163-8 , pp. 255–288, here p. 286.
- ^ Otterndorf water and soil associations: Modernization of the Otterndorf estuary pumping station
- ↑ The construction of the Hadelner canal lock is a done deal
Coordinates: 53 ° 49 ′ 22.7 " N , 8 ° 53 ′ 37.2" E