Flood protection for Hamburg s Niederhafen port. Construction of the new Niederhafen flood protection barrier in Hamburg city centre

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1 Flood protection for Hamburg s Niederhafen port Construction of the new Niederhafen flood protection barrier in Hamburg city centre

2 Construction of the new Niederhafen fl ood protection barrier Plans have been drawn up for the construction of the new flood protection barrier over a length of 625 m at the Niederhafen port between St. Pauli Landungsbrücken and Baumwall. Reason for action Flood protection requires foresighted action. Today s meas urement and calculation methods, computer simulations and scientific findings enable us to analyse storm surges with greater precision and make better forecasts of future flood characteristics. As part of an extensive construction programme, Hamburg is modernising and reinforcing its flood protection barriers in order to increase safety for people, goods and property. Location The Niederhafen flood protection section is an exposed location in Hamburg which includes the city s best-known promenade, a major attraction for tourists from all over Germany and even further afield. The promenade links St. Pauli Landungsbrücken with the historic Speicherstadt warehouse area. As the HafenCity area is developed further, this harbourside promenade will become even more significant. Existing structure The current construction came into being between 1964 and 1968 as part of the modernization of Hamburg s flood protection system in the aftermath of the storm surge in Taking account of traffic planning for the harbourside road and an intended partial shifting of the elevated railway s viaduct, the shoreline was shifted out into the Elbe by up to 20 metres during this period. The barrier structure gives protection up to a height of 7.20 m above sea level (a.s.l.). Both the shoreline and the viaduct follow the historical structural line of the commercial and residential buildings along the streets Vorsetzen and Johannisbollwerk. This results in the distinctive sharp bend in the shoreline at the Niederhafen port about halfway along this stretch, a spot which is emphasised to this day by the fortification from the Second World War. The promenade on top of the flood protection barrier provides an undisturbed view of the Elbe and the port. Below the promenade, parking spaces are provided within the structure itself. A preliminary inspection revealed that significant supporting elements of the present structure are overburdened and that the foundations, in particular, are in need of reinforcement. Increasing the existing barrier s height would be structurally very complex and elaborate, as well as unsatisfactory from a technical point of view. Planning In the Hamburg Architectural Olympics competition in 2006, urban planning requirements for a redevelopment of the installation were formulated as follows: In the last analysis, the intention is that in addition to the flood protection barrier, an attractive promenade should be devel oped in an exposed position in Hamburg. The promenade should be suitable for a variety of uses, function as a high- calibre connecting path, and generate numerous pathway intersections while simultaneously helping to define the cityscape. Picture 1: Plans, aerial photo montage from the west For you. For Hamburg.

3 E l b e N i e d e r h a f e n Site plan: Plans with connecting pathways to the urban residential area Picture 2: Plans, view of Baumwall The plans for the redevelopment work are in conformity with the award-winning design draft prepared by the architecture firm Zaha Hadid, whose central approach is to open up the promenade to the urban surroundings and the water. To achieve this, the linear structure which lies high above street level because of the flood protection system will be hollowed out at the points where streets from the adjacent urban district meet the barrier structure. The solution comprises cone-like insections for stairs whose shapes resemble that of small amphitheatres. In this way, passers-by at street level will have an undisturbed view of the people strolling along the promenade and the masts and superstructures of the ships in the Niederhafen port. Similar stairs will be constructed on the Elbe side in alternation with the access paths from the city centre. For the promenade, this alternation will bring about an oscillating sequence which repeatedly narrows and expands. On the shore side, a number of buildings whose ground floors are to be made accessible from street level will be integrated into the overall structure. The existing structure will be demolished for the redevelopment work. The new structure has been planned as a massive construction with deep foundations. As the new flood barrier will be higher and wider in overall terms, a cantilever structure into the Elbe will also have to be included. A minimum width of 10 metres has been stipulated for the promenade. There will again be car parking facilities within the structure, and on the street side it will be possible to accommodate shops and other utilisations. Picture 3: Existing structure, view of Baumwall

4 C i t y S p o r t h a f e n Picture 4: Existing structure, flood protection with promenade Planned cross-section with waterside stairs Protected height Elevated railway Notional max. water level Parking level Shop Footpath Cycle lane Road Median strip Service road Average high water level Retaining wall Main sewer Average low water level Retaining wall The shore-side stairs will be oriented towards the streets Stubbenhuk, Neustädter Neuer Weg, Rambachstraße, Reimarusstraße and Ditmar-Koel-Straße. New pedestrian crossings are going to be built to connect these with the promenade. The stair units facing the water side will also provide seating facilities, thereby making it possible to enjoy the undisturbed view of the port, the harbour ferries, and the Cap San Diego and Rickmer Rickmers ships away from the flow of pedestrians on the promenade. The platforms of these stairs on the water side are planned to be 5.40 m a.s.l., which means that they will be submerged by the Elbe only during very severe storm surges in the autumn and winter months. Thanks to the shore-side utilisations within the structure itself, the access paths to the parking facilities and the special shape of the stairs, the new facade facing the city side will be more appealing than the present construction. On the street side, a pavement will be laid along the entire length of the construction. Here, for the first time, there will also be a separate cycle lane for cyclists heading towards the city centre. Ramps located at Baumwall and Landungs brücken will connect the facility with street level in a manner that provides full accessibility for the physically handicapped. And a third ramp, located centrally between the two, will ensure continued access also for motor vehicles to the Überseebrücke. Extension heights When a new flood protection barrier is being built or an existing one significantly reinforced as part of the construction programme, allowance must be made for a possible further increase of 0.80 m (extension capacity) in the future. In the Niederhafen flood protection programme, this extension capacity is already being added (single-stage extension). This provides both the best, from a design point of view, and the most economical solution under the specific conditions imposed by the location and the plans. The extension heights are 8.60 m a.s.l. in the eastern section of the new structure and 8.90 m a.s.l. in the western section. Construction schedule The construction schedule provides for two construction stages over the length of the construction site which are to be completed consecutively, beginning with construction stage 1. The stage is structured in such a way that the access restrictions will be kept within specified areas. When the work is being performed in construction stage 1, the promenade to the west of the Überseebrücke will remain unaffected. During construction, restrictions will also be necessary in the areas adjacent to the construction site. The street sequence Johannisbollwerk, Vorsetzen, Baumwall will, depending on the progress of construction, be used partly for construction site purposes and therefore be restricted to one lane for

5 Construction stage 2 Construction stage 1 Construction schedule construction stages drivers. The water side will also be affected, however. There, ground areas will be closed section by section for work and material pontoons and/or jack-up platforms, and pontoons will be moved temporarily. Not only protection from storm surges in the winter months, but also the protection of low-lying areas of the city from summer high tides, must be guaranteed at all times. In addition to this essential basic condition, access paths must be maintained as far as possible and must continue to be The history of the Niederhafen port The Niederhafen was a significant commercial port in Hamburg from the 17th to the 20th century. When the Binnenhafen port at the mouth of the Alster was no longer able to absorb the briskly expanding volume of overseas trade, further berths were set up downstream. The name Niederhafen ( low harbour ) arose from the position of this port area beneath the timber raft barrier ( Niederbaum or low raft) between Baumwall and Kehrwiederspitze, which served to safeguard the entrance to the port. The expansion of the ramparts, the city s fortifications during the Thirty Years War, also shaped this area of the harbour front with the Johannis bastion, a reminder of which is still provided today by the street name Johannisbollwerk. Up until the start of the 18th century, the berths were extended several times using rows of pile moorings. Here, the cargo from the large ships arriving from overseas was transshipped on to smaller barges and lighters. The Johannis bastion, which stood until 1838, was demolished to make way for a massive bank wall. In 1873, the built-up street Vorsetzen was broadened with a bank wall measuring some 16 m. As early as 1889, this wall was so dilapidated that it had to be closed and operations using manual swivel cranes had to be abandoned. In 1893 a new quay wall was constructed with a massive superstructure and a foundation of wooden stakes. The shoreline was again pushed out into the Niederhafen, this time by 20 m. A temporarily erected English church situated level with the site of the former bastion had to make way for the development of the port. Quay sheds for domestic German maritime traffic on the Hamburg-Rhine line were erected for port transhipment purposes and the quay wall was equipped For you. For Hamburg. made attractive for visitors and tourists as well. The hub of the construction stages will therefore be the Überseebrücke bridge. The Überseebrücke s bridgehead will have to be expanded. Here, a temporary bridge will continue to ensure access to the Überseebrücke s pontoon facilities, the Cap San Diego, and the Vorsetzen pontoon including the launches and the City Sporthafen recreational harbour. Passability for pedestrians and cyclists in the construction site area will be guaranteed by signposted alternative routes. with gantry cranes. After the Second World War, quayside cargo handling was discontinued here, and in the 1950s all the sheds were demolished, with the areas being levelled and some of them used as car parking facilities. After the flood in 1962, the present-day flood protection barrier was erected along with the promenade. This was followed in the 1980s by the construction of the road along the harbour front. Picture 5: Vorsetzen ca Picture 6: Johannisbollwerk ca. 1930

6 Hamburg s public flood protection line Length 103 km of which dykes 78 km of which flood protection walls 25 km Constructions 82 of which storm surge barriers 6 of which locks 6 of which tidal gates 20 of which pumping stations 10 of which gates and other closing devices 40 Niederhafen flood protection data Length of the enhanced section 625 m New, increased height 8.60 to 8.90 m a.s.l. Planning approval procedure Application Dec. 2009, approval March 2011 Scheduled construction period Publisher, contacts Project management Landesbetrieb Straßen, Brücken und Gewässer Divison of Surface Waters and Flood Protection Phone (040) Architecture ZAHA HADID LTD ARCHITECTURE Project and support structure planning INGENIEURBÜRO GRASSL GMBH Road and traffic planning SCHMECK-JUNKER INGENIEURGESELLSCHAFT MBH Technical building services RMN INGENIEURE Geotechnical consulting GRUNDBAUINGENIEURE STEINFELD UND PARTNER GBR Environmental impact assessment LANDSCHAFT & PLAN Design, picture credits Design Hamburg Agency of Geoinformation and Surveying Picture credits Cover picture Picture 1, 2 and 3, montage Picture 4 Picture 5 Picture 6 ON3 Studio ON3 Studio LSBG Photography by Otto Reich, Museum for Hamburg History Photography by Strumper & Co., Museum for Hamburg History updated January 2013