Dealing with Potential Flooding

The entire Hafencity area is located outside the flood protection structures (Fig. 3.36).

Fig. 3.36 Flood protection plan (Source: GHS, 2002)

This means that two options for protection are available: close the area with a dike or adjust the urban design to flooding and high tides. Because a dike would have disconnected the site from the river physically and visually, the choice was made to find solutions in the urban design. This resulted in a two-level city. A part of the site is heightened in order to stay dry during high tides and the rest of the area, the lower levels, is prepared for wet circumstances. The elevated parts are realised at least at 7.5 above normal level. Footbridges and bicycle-paths at these levels can be used for emergency transportation and evacuation in periods of flooding (Fig. 3.37).

The heightened parts are located in the central areas of the piers and are at least 20 m away from the quay. This results in lively interaction between public space, which occasionally is flooded, and the water of the river. The ground level of the buildings is positioned at least 20 m away from the quay, but it is aloud to build

Fig. 3.37 A footbridge becomes an emergency and evacuation route (Source: GHS, 2002)
Fig. 3.37 (continued)

second floors over the public space and the water. This results in the design of unique buildings (Fig. 3.38), which are overlooking the water-edge, but are also including public spaces and routes. The base of the buildings is treated in order to withstand flooding by the use of extra thick glass for the windows on the ground floor and by using wooden protection against large floating material.

Because the entire area contains these unique 'balcony-buildings' it seems that this part of the city centre is uplifted and becomes more or less footloose, even if there is no flood (Fig. 3.39). The Hafencity area is lived at three levels: the water level, ground level and balcony level.

The Hafencity project illustrates that high tides and floods can be inspirational and lead to architectonical and urban diversity. The threat is not opposed by a pure technical and single-minded solution, but forms a challenge for the urban design.

Fig. 3.38 (continued)

Fig. 3.39 Elevated buildings above a flood level proof public space (Source: GHS, 2002)

This approach combines the safety of the inhabitants of the area with spatial qualities. The area contains different habitats during times the environment is changing. It is positioned in, on and along the river Elbe.

3.4 Thames Gateway - London 3.4.1 Thames Estuary 2100

The estuary of the Thames is in direct connection with the North Sea, which indicates that tidal influences will be felt in the Thames. As sea level rises and amount and strength of storms increases the chances at flooding are increasing as well. In order to prepare the estuary for these future changes the so-called Thames Estuary 2100 project is conducted.

In general, the UK Environment Agency defines four major focal points in adapting the country to climate change (Environment Agency, 2007a). The first point is to increase the investments in flood defences. Secondly, a more strategic approach to manage the coastline is required. Organisations that are involved along the coast need to work together to take sensible, long-term decisions about the way the coasts are used. The protection of the coast from future flooding and the risk of storm surge, as well as realignment, and possibly relocating people and homes or abandoning agricultural land needs to be reconsidered. The third objective is to use water more efficiently, because due to climate change it is expected that the amount of available water will decrease. Finally, conservations and habitats need to be protected. Existing nature conservations are to be made resilient to climate change and the movement of species needs to be encouraged by managing habitats at a landscape scale.

The effects of climate change, such as sea level rise, increased rainfall and storm frequency mean that London and the Thames Estuary will be at greater risk of flooding in future years. Furthermore, many flood risk areas are undergoing development and regeneration, meaning that more people, buildings and infrastructure are likely to be exposed to the risk of flooding in the future.

Although London's existing tidal defences offer a high level of protection from today's flood risks, they were only designed to provide protection up until 2030. While slight modifications to these defences could extend their useful life by a few more years, the need for a long-term, strategic look at London's flood defences is becoming increasingly apparent.

Thames Estuary 2100 is an Environment Agency project (Source: www.environment-agency.gov.uk/te2100) to develop a tidal flood risk management plan for the Thames estuary through to the end of the century. The final plan will recommend what flood risk management measures will be required in the estuary, where they will be needed, and when over the coming century, based upon the climate changes and sea level rises we face.

The plan will take into account the increasing flood risk due to:

• Natural ageing of flood defence infrastructure;

• Changes in land levels;

• New developments in the tidal flood plain.

Thames Estuary 2100 is the first step of the process and will help shape the way in which future flood defence schemes are designed and managed. Taking action now will allow time for research, design and the physical construction of the defences. Thames Estuary 2100 aims to:

• Look at tidal defences in the context of the wider Thames Estuary setting;

• Assess the useful life of the existing defences and gain an understanding of the 'drivers' (i.e. climate change, urban development, social pressures and the environment);

• Inform and gain support of political and funding partners and stakeholders; and

• Prepare and manage a programme of studies (linked with consultation) that will eventually lead to a strategy for flood risk management in the Thames Estuary for the next 100 years.

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