Editing Aller (Germany) (section)

=== Current flood protection ===
In the years 1954–1962, there was increased flooding along the Aller, which caused considerable damage to its water meadows. The flooded areas in the Aller valley varied between {{convert|300|and|5000|m|ft}} wide, mainly due to the uneven flow of the river. In 1961, the [[Landtag of Lower Saxony]] decided to regulate the Aller by widening it. The aim was to protect settlements as well as the agricultural economy of the villages and towns along the course of the river which were generally poorly protected from flooding. Most of the measures to regulate the Aller were established in the 1960s. They were followed by the construction of a {{convert|15|ha|acre|adj=on}} [[retention basin]] near Gifhorn in the 1970s. By contrast, plans for a retention basin on the bend in the Aller near [[Grafhorst]] were scrutinised between 1993 and 1996 on environmental grounds.<ref>
[http://www.wpk-gbr.de/allerknie.htm Allernknie] {{webarchive|url=https://web.archive.org/web/20050824151819/http://www.wpk-gbr.de/allerknie.htm |date=2005-08-24 }}</ref> The planned {{convert|12.5|km2|sqmi|adj=on}} "Fahle Heide" basin west of Gifhorn was never built due to lack of funding. As part of the widening of the Aller the banks were reshaped along large stretches. The state purchased strips of land up to {{convert|12|m|ft}} wide from those living along its banks. The banks were made flatter and lined with stones. Willows, alder and reed beds were planted. The Upper Aller was widened to {{convert|15|m|ft}}, the Middle Aller to {{convert|30|m|ft}} and the Lower Aller from its confluence with the Leine to {{convert|50|m|ft}}. Flood embankments were built along the Lower Aller near [[Rethem (Aller)]], [[Westen (Dörverden)|Westen]] and [[Häuslingen]].

==== Flood protection in Celle region ====
[[File:AllerAltencelle.jpg|thumb|The canal-like widened Middle Aller near [[Altencelle]]]]
As early as the 1980s the town of Celle had drawn up a "Plan for Flood Protection of the Celle Region".<ref>[http://www.celle.de/media/custom/342_6602_1.PDF Rahmenentwurf zum Hochwasserschutz der Region Celle]</ref> This described a combination of widely varying measures, such as excavation of the river shore, flood basins and dykes. On 6 June 2005 the town received authority to start the first stage of the flood protection project. In 2006 work was begun.<ref>[http://www.nlwkn.niedersachsen.de/master/C14994627_L20_D0_I5231158_h1.html NLWKN: Start der Hochwasserschutzprojekte in Celle]{{dead link|date=July 2017 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> This first part of the work entailed excavation of the river shore between Boye and the confluence with the river Fuhse, which were intended to increase the cross-section of the Aller channel during high water periods.<ref>[http://cdl.niedersachsen.de/blob/images/C17829250_L20.pdf Übersichtskarte der Vorlandabgrabungen in der Region Celle]{{dead link|date=July 2017 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> The flood basins have an area of about {{convert|15|ha|acre}} and are {{convert|1.5|m|ft}} deep, requiring about {{convert|240000|m3|ft3}} of earth to be washed away. The cost of the project came to around {{Euro|2{{nbsp}}million}}. Only two years later, it was determined that these first interventions of the river system had resulted in sand being permanently deposited in the Aller producing shoals. In May 2009, the shipping channel was dredged for the first time in the vicinity of the new flood basins so that ships could once again pass through. Now,{{when? |date=November 2024}} it is planned to redesign the basins and, in some cases to fill them in, in order to reduce the future dumping of sand.