A Conceptual Design of a Floating Island City for Overcrowded Countries




Carl T.F. Ross & Mohamed Amin Afshar

(University of Portsmouth, United Kingdom)





The paper presents a conceptual design of a floating island city.   The authors commence the paper, by explaining the need to build floating island cities, because of increasing global populations and the possible forthcoming decrease in dry land area, due to climate change and flooding.  The paper then discusses the history of the design of floating island cities and states why they should be preferred to land reclamation projects.  The paper then discusses the current design in some detail, which is called 'Water Britain' and shows that the project is feasible.  The city is to be built on a rectangular pontoon of length about 2.8 miles (4.5 km) and of width about 1.8 miles (2.9 km).  The vessel is designed to house about 50,000 inhabitants.  In additional to residential accommodation, the city will have 'high-class' retail outlets and 'high-tech' type industries, together with schools, a university, a marina, a hospital, leisure areas, etc., etc.  It is expected that the cost to build the floating island city will be about £15 billion.


1.0 Introduction

1.1 Motive

The Ice Mountains on Greenland are melting. Now Greenland is the second largest island in the world; its surface area is about nine times that of the UK and if these ice mountains continue to melt at their current rate, then it is believed, that by the turn of the present century, they  will completely disappear.  As a result of this, the Earth’s sea levels will rise by about 6.7metres (22ft)  (see the ‘Global Warming’ page on Carl Ross’ Website). This therefore may cause flooding, on an unprecedented scale to low lying cities such as London and Portsmouth.  Indeed, the majority of the land on Portsmouth is a maximum of only about 3m (9.84 ft) above sea level and therefore a rise in sea levels will  cause considerable damage to the city; unless a solution can be provided. One such solution, that is put forward in this paper is to design and construct a floating island city, which in this paper is called ‘Water Britain’.  Today, Portsmouth is the second most densely populated city in the UK; after inner London. Furthermore, it's estimated that its population will increase by between 2.5% and 4.9% in the year 2015. This will not only lead to a rise in traffic, noise pollution, and air pollution, but also the population rise will increase the demand for housing. Should the supply of housing fail to keep pace with demand, then house prices will clearly increase; a feature, which we have already seen in the 2000's. What’s more, such a rise in population will increase the need for additional land for people to live on; in the present paper, a floating island city is proposed. This is because only 29% of the Earth's surface is dry land and in the 21st century, in order to cope with a global population rise, which is likely to increase from about 6.5 billion to about 9 billion in 2050, the seas will have to be colonised! Of course, the land to the north of Portsmouth can be converted to housing. However, this will detrimentally affect the natural environment and will almost certainly arouse protest among various pressure groups. The sea to the south of Portsmouth, however, provides the potential for locating a floating island city. This can be an attractive possibility to some of the existing residents of Portsmouth. Such a concept could also help solve similar problems associated with other overcrowded places, such as the  Netherlands, Hong Kong, Singapore and Japan. Moreover, on the 25th June, 2008, the 'Bush' White House announced that rising sea levels were a threat to western global defence, because many of the military establishments would go underwater, due to rising sea levels.  On the BBC 2 'Newsnight' TV programme, figures of $50 billion were mentioned to overcome the problem!  This statement makes the building of a floating island 'city' a much more viable proposition.


1.2 The advantages of a floating city over traditional land reclamation

The advantages of adopting a floating island city, instead of using land reclamation are as follows

·     It is cost effective when the water depth is large.

·      It is more environmentally friendly; it does not damage the marine eco-system or silt-up deep harbours or disrupt tidal/ocean currents.

·      Floating island cities are easier and quicker to construct than land reclamation projects.

·      A modular form of construction allows expansion of the city to be carried out easily; the modules can be launched from their building berths and then floated to the site, where they can be assembled.

·      It is protected from earthquakes, cyclones and tsunamis.

·   Floating Island cities do not suffer from soil subsidence.


1.3 The State of Art of Floating Technology

During the 20th century, large  floating technology has appeared in the form of storage facilities, emergency bases, oilrigs, bridges, power plants, docks and piers and the idea of floating island cities first came into fruition in the 1970s.  This was the construction of a semi-submersible unit of a floating city, which was produced at the Okinawa International Ocean Exhibition . Many design sketches of floating cities have since been drawn, but no floating island cities have actually been built.


1.4 The Proposed Designs of some Floating Island Cities


1.4.1 The Floating City ‘IjmeerText Box: 1990’s

In the Amsterdam-Almere region, there appears to be a rapid increase in population. This, together with climate change, rising sea levels and ongoing urbanisation, has prompted a study of the design of a floating island city. Students at the Delft University of Technology, Netherlands, proposed the design of locating a floating city in the Ijmeer region. This was, and we quote, from their 'publication', to “develop a more self-supporting, non-risk concept of urbanisation in the Almere-Amsterdam region, that will contribute to further economic and technological development in the Rhine Delta”. This floating city, shown in Figures 1 and 2; will provide accommodation for an area, where, the opportunity for housing development is somewhat limited and there exists a shortage of homes.



Figure 1:Ijmeer Floating City’. (1, highway bridge connecting Amsterdam with Almere; 2,road leading to ferry port; 3, metro station; 4, dock for big ferries and private boats; 5,  parking facilities; 6, dock for carrying inhabitants cars to their homes; 7, 8 floating pathways (car access only allowed for emergencies); 9, Accommodation unit with 60 houses; 12, courtyard providing access to people homes; 18, Accommodation unit with 12 houses)



Figure 2:  Cross-section of an accommodation unit for the floating city ‘Ijmeer’. (12, spacious courtyard; 16, closed loop water heat exchanger; 21, mooring facility)



1.4.2 ‘Triton City, USA’

Waterfront living is a much required facility of a city  in the USA and because of this the 'Triton City' design was carried out.  The city offers the advantages of rapid access to the downtown area and also has a suburban open space view. During the 1960s, the supply of such property with waterfront living was somewhat limited in the USA, in which existing structures were old and their renovation and refurbishing was extremely expensive (Triton Foundation and R. Buckminster Fuller). Even today, waterfront living in a city, can only be afforded by people on high incomes. To make waterfront living affordable to those on  middle incomes, the United States Office of Housing and Urban development came up with the idea of placing a floating module on the waters near the urban area, which can be used for living space. It was anticipated that this floating city could commence with a population of between 3,500 to 6,500 people; about the size of a neighbourhood community. It was realised that a  population of about 5,000 would be enough to support an elementary school, a supermarket, and local convenience stores and some services. If the community reached from15,000 to 30,000, then it would be considered to be a town. In this case, an additional modular unit will have had to be added, so that it may include a high school, more recreational facilities and also some industry. If this community reached a population of between 90,000 to 125,000, it would be considered to be a city. An additional module would have to be  be incorporated; this would provide facilities for government offices, medical facilities, a shopping centre and perhaps  a community college and more  industry.


1.4.3 ‘Sea City’

‘Sea City’ was a conceptual design for a self-sufficient floating island city, which had a  multiple industry community of about 50,000 people; it was put forward as a feasibility study by Kay van Dyke, a civil engineer at Kirkland Civil Engineering.

The sea environment at which a city was to be placed influences its design and Van Dyke realised this and  put forward a design, which varied for each ocean environment. In the case of the open sea environment, where the hydrodynamic forces acting on the structure are the highest, Van Dyke based his design on a floating marine community of 15,000 people, as proposed by John Craven, Hugh Burgess and Kiyonori, at the 1976 ocean exhibition in Hawaii. Craven et al’s design used a pattern of semi-submersible units (see Figures 4 and 5), arranged in a circle, where each unit was designed to minimize the surface area presented to the waves at the waterline. The use of narrow columns supporting platforms above the wave level allowed these units to reduce the hydrodynamic forces from the waves. On these platforms were living and working space modules. Sea City used 3.3 of Craven et al’s marine community units.





Figure 3: Model of the 'Triton' floating city module












Figure 4: Cross section of a semi-submersible             Figure 5:  Craven et al's Marine community for 15,000 people

 unit for Craven et al’s Marine community




It is worth pointing out that Consafe Offshore of Sweden, built a semi-submersible unit, for North Sea oil operations, similar to the one put forward by Craven et al. The unit included a fresh water supply, a sewage treatment plant, medical service equipment, recreation rooms, kitchens, a bakery, a mess hall, and oilrig equipment. According to Van Dyke, to build 'Sea City', it  would require 83 of these units for living space and another 50 units for other needs.

With regards to the coastal waters' category, where the hydrodynamic forces on the structure are lower than in the open sea, Van Dyke proposed the use of barges that held lightweight structures. This was a rather more simple structure than the one proposed by the Pilkington Glass group (see Figures 6 and 7). An example of Van Dyke’s proposal is the ABS class A1 ocean-going barge (see Figure 8) which can accommodate 1,200 people in 4-men cabins and includes medical facilities.  It also included recreation space, food service, fresh water, sewage treatment; all in modules stacked 4-6 storeys high. According to Van Dyke, to build 'Sea City', it  would need 42 of these barges for residential space, and another 30 barges for commercial and industrial spaces.

















Text Box: Figure 6: Cross section of the Pilkington Glass proposal showing mechanical rooms, 19 storey breakwater
Text Box: Figure 7: Model of the Pilkington Glass proposal for a city of 30,000















Text Box: FFigure 8: An ocean going barge 

2.0 Population of the proposed Design, namely ‘Water Britain’.


2.1 Population Size

Population size will influence the design of the proposed floating city. To begin with, we will use a relatively small population. The population for our floating city will be around 50,000, which is relatively small for the UK; it is about a quarter of the population of Portsmouth.

Comparable towns in the UK include (2007 figures) the following:

Winchester     41420 people

Lancaster       45952 people

Canterbury     43552 people


2.2.0 The breakdown of the Population of the proposed city

2.2.1 Households


Household Composition



Estimated No of people in Water Britain living in this household type

One-person households



Married Couple Households without children





Married Couple Households with children





Cohabiting Couple households*

(without children)





Cohabiting couple households with children





Lone parent households



Other(e.g. Students transients etc)



*Percentage of cohabiting couple households with/without children based on Portsmouth


Table 1: Household Composition in ‘Water Britain’, based on average of 4 UK cities (See appendix 1)


2.2.2 Family Size

Household composition

Family Size

One-person households


Married Couple Households without children


Married Couple Households with children


Cohabiting Couple households (without children)


Cohabiting couple households with children


Lone parent households











Table 2: Family Size in Water Britain based on UK Average of 1.8 children per family




3.0 The size of ‘Water Britain’


The current population of Portsmouth is approximately 200,000 and its land mass covers an area of approximately 40 km²(15.45 mi2). In order to attract people to live in the proposed city, namely ‘Water Britain’, we need to provide them with either a financial incentive such as a reduced council tax or an opportunity for better employment or an improved quality of life. Therefore it is proposed that ‘Water Britain’ should have a lower population density than Portsmouth. For the purpose of this study, we shall assume that the size of ‘Water Britain’ should be 13 km² (5 mi2- about one-third the area of Portsmouth); a pontoon of size 2.8 mi (4.5 km) by 1.8 mi(2.9 km) might be suitable for carrying the city. 



4.0 The development of ‘Water Britain’


A floating city will be considered a massive undertaking. Table 3 shows some examples of very large projects and their associated developers, in which either a national government or a financially capable company or a consortium of companies built them. Although not a viable option for ‘Water Britain’, a floating city could also be built by a consortium of local authorities as a way to relieve themselves from their overspill populations. An example of this is Milton Keynes, which helped remove the over crowded areas of London by attracting their overspill population into this new town. Once populated, this city will be managed by the local authority; in this case either Portsmouth City council or Havant Borough Council or similar.







Channel Tunnel

Consortium of companies

Airbus A380

Company with annual revenues exceeding $39 billion

Trans-Alaska Pipeline System

Consortium of companies

Three gorges Dam













Table 3: Examples of Super-Engineering Projects.



5.0 The Market for ‘Water Britain’


5.1 Product and Customers

The revenue from building this city will come from renting or selling the structures, which make up the city such as houses, retail units, industrial units, hotels, hospitals and offices, etc.


5.2 The potential for success                                                     

The advantages of living in this city are:


·      Being free from natural disasters such as earthquakes or floods or tsunamis.

·      Living in a better quality property at slightly higher costs.

·      Having a more temperate climate around you.

·      Possibility of a safer environment.

·      Far less pollution.

·      Modern Surroundings.


A floating island city may eventually attract investment from businesses, particularly those within the service sector. This will bring its own benefits, such as employment, which itself will have a multiplier effect in terms of increasing disposable income among the inhabitants; this will generate a demand for goods and services, thus enhancing the financial health of existing businesses, while generating further interest among new investors.

Ultimately, the floating city will have all the benefits that one may find in land-based cities, without some of the necessary problems.



6.0 The location of the floating city


6.1 The Sea Environment

The 3 types of ocean environments include:

1. Open sea - over 12 nautical miles from the shoreline, with

2. Coastal waters - Within 12 nautical miles from the shoreline

3. Protected waters (e.g. Langstone Harbour, Portsmouth Harbour) - significant wave height of 1.04m at Portsmouth Harbour entrance and a wave height of 2.10m at Langstone harbour entrance.

The further away this city is from the shoreline, the higher the construction costs, the increase in travel expenses of its inhabitants and the more isolated its inhabitants may feel from the rest of the country’s population. Placing this city in the open sea should not therefore be an option for the proposed ‘Water Britain’ city. Protected waters near Portsmouth, such as Langstone Harbour and Portsmouth Harbour, are too small and are not practical locations to locate such a structure and may arouse heavy opposition. This therefore leaves coastal waters as the most suitable sea environment for the proposed city.


6.2 The Site Allocation of the city

When determining the site of this floating city, the following things must be considered:

·      Effect on people living in neighbouring towns (e.g. Portsmouth or Hayling Island)

·      Travel distance for its citizens when going to the mainland for work or other reasons

·      Draft Limit - when designing the pontoon, the draft limit must be of such length so that the effect of tide does not cause the pontoon base to come into contact with the seabed. The draft limit h required is determined using the buoyancy equation:


Text Box: Where 
m = mass of city in kg
g = acceleration due to gravity=9.81ms^-2
ρ = density of sea water = 1032kg/m³
V = volume of water displaced by the pontoon base in m³ = Area of pontoon in m² × Height of pontoon submerged in water in (m)=Ah







The mass 'm' of the city can only be found once the space requirements for all elements of this city are determined and their weight is estimated. An admiralty chart (see Figure 9) can be used to determine which part of the sea meets the required depth.  According to our calculations, the draft for our floating island city, with mostly 3 storey buildings, will be about 5m; see later in the present text.





Figure 9:  A sample from an Admiralty chart



·      Laws and regulations - as the concept of a floating city will be new to Britain, it is expected, that certain laws and regulations that are in existence should be adapted or changed to allow for such a project to go ahead. The Coastal Protection act of 1949, amongst other acts, is concerned with the issue of positioning such a structure in the sea. This act takes into account the danger or obstruction to navigation when deciding where to position this city.


7.0 The design of ‘Water Britain’


7.1 Analysis of existing concepts.

Several existing conceptual designs, which have been mentioned in the introductory section, are evaluated here, together with their advantages and disadvantages.

7.1.1 The Floating City ‘Ijmeer’

Although industry has not been included in this design, this can easily be added with the addition of more pontoon modules.



· Idea of preventing cars from driving over the bridge reduces the threat of road accidents

· Uses of maximum potential of water; both as an infrastructure and as an open space.



·        Some rooms  are very close to the motorway


7.1.2 'Sea City' (coastal water category)


·        Space efficient

·        Simple to construct


·        Not very attractive


7.1.3 'Triton City'


·  Space Efficient

·  Versatile



·  Very dense construction

·  Not very attractive


7.2 The design concept of ‘Water Britain’

The proposed design must include a large pontoon floating structure, a mooring facility to keep the floating structure in place and an access bridge or floating bridge to get to the floating structure from shore and a breakwater.



8.0 Facilities and other requirements


8.1 Residential Accommodation


Based on information from the Chartered Institute of Environmental Health, the minimum space required for each room in a house in multiple occupation (e.g. students) accommodating 5 people is as shown in the following table:








Dining Kitchen


Bedroom 1 (2 people)


Bedroom 2 (2 people)


Bedroom 1 (1 person)


Living Room




Bathroom*                                          2.9m²

Total Living Area (LA)              69.44m²

Adding 50% for the structure, partitions, exterior circulation, corridors etc (Triton Foundation, 1968) brings the total space S to approximately 100m².

Space for building plot P is given by



P=Building foot print size

S=Total Space

N=Number of floors


If number of floors N is 2

Assuming the exterior  space,  such as (garden, drive way, etc.) is the same as the building foot print, the total plot size PT is approximately 100m².

In table 4 are given the accommodation sizes given to houses outside the category of a house in multiple occupation;  flat sizes are also included.



Accommodation Type

No of People












Approx 60










Approx 60

































Luxury Houses






















inside 3 storey building


equal to 1 plot size









inside 3 storey building











Inside 3 storey building




 Table 4: Accommodation requirements



Household Composition

  Accommodation type suited for this kind of household composition



One-person households

·      2 bedroom terraced house

·      2 bedroom flat

·       2 bedroom semi-detached house

·       Studio Flat


Married Couple Households without children

·      2 bedroom terraced house

·      2 bedroom flat

·      2 bedroom semi-detached house

Cohabiting Couple households

(without children)



Married Couple Households

with children

·       3 bedroom detached/semi-detached house

·       Small or medium sized 4 bedroom detached house

·       4 bedroom semi-detached house

·       4 bedroom terraced house

Cohabiting couple households with children



Lone parent households

·       4 bedroom detached house

·       4 bedroom semi-detached house

·       4 bedroom terraced house



















Table 5: Relationship between household composition and accommodation type




8.2 Accommodation for short –term basis

Accommodation Type (Catered)


Size (s) in m²

 5 star Hotel: 4 storeys



2-4 star hotels: 4 storeys




Bed and Breakfast: 2 storeys






Whereas most cities draw tourists because of their cultural heritage and sporting events, the floating city that this paper proposes will draw tourists because it will provide a new and different experience. The city will undoubtedly be an engineering marvel, fulfilling people’s imagination. Table 6 below gives the size and quantity of serviced (catering included) accommodation required for this city, that is accommodation targeted at tourists. Non-catered accommodation could include student halls of residence as they are unoccupied by students for 5 months of the year.







Table 6: Hospitality services – Type, Quantity and Size



8.3 Schools, Colleges and a University

The following information is based on the data obtained from National Statistics Office.

The age range of pupils within the different types of schools in the UK can be seen from Figure 10.


Figure 10


Grammar schools have been excluded from this list since only 4% of people in England are educated there. The data in Table 8 gives an estimate of the number of people in each age group within this city, which covers a portion of school/pre-school age. These values have been based on the average value for each age range for seven British cities.












0 - 4








0 - 5








10 - 14 








15 - 19









Table 7: The percentage age group breakdown for 7 UK cities



Age range

Average (%)

Number in this age group



(6.04/100) × 50000 = 3020



(6.30/100) × 50000 = 3150



(6.50/100) × 50000 = 3250



(7.40/100) × 50000 = 3700








Table 8: Numbers in age groups


Table 9 gives the percentage of 3-4 year olds taking up early education places by type of provider, expressed as a percentage of the total 3-4 year old population of England.




Education Provider

% of 3-4 year olds in education by type of provider in England

Private and voluntary providers


Independent schools


Maintained nursery and primary schools


(56% Full Time)

Special schools










Table 9: Percentage of 3-4 year olds taking up early education places by type of provider.


We should note that the total does not add up to 100, as children attending more than one provider may have been counted twice and will thus have affected the percentage values.  Also, these values take into account the number of 2 year olds receiving education. Since the number of 2 year olds in education is very small compared to the number of 3-4 year olds, their population estimate for this city will not be taken into account when estimating the number of people requiring pre-school education in this city. Using these percentage values, as if they took into account the 3-4 year olds and assuming there is an equal amount of people in each of the age years of the age group 0-4 (1208 per year), an estimate of the number of 3-4 year olds receiving education in this city by type of provider can be given by Equation 1. The results are shown in Table 10.


Text Box: Number of 3-4 year olds receiving education  
by this type of provider 
Text Box: % 3-4 year olds receiving education  
by this type of provider in England                            
Text Box: Estimated number of 3-4 year olds in this city           
Text Box: × 
Text Box: =
Text Box:  




Equation 1.





Estimated number of 3-4 year olds children attending

Private and voluntary providers


Independent schools


Maintained nursery and primary schools


(117 four year olds at primary school)

Special schools










Table 10: Estimate of number of 3-4 year olds receiving education in this city by the type of provider



This method can also be used to determine the number of people in primary and secondary education in this city.

Education is compulsory between the ages of five and sixteen and is divided into a primary and secondary stage. Using the data from table 3 an estimate of the number of people, where full time education is compulsory to them at primary level (age 5-11), assuming there are an equal amount of people in each age of the age groups which are linked to primary school, is:


As some 4 year olds will also be attending primary schools for their pre-school education, there number must also be accounted for to determine the total number of people attending primary level schools in this city. Therefore, assuming there are an equal amount of 4 year olds in each of the three types of maintained schools, the number attending primary schools using table 5 is


Four year olds


To work out the number of people where full time education is compulsory to them at secondary school level (age 11-16), we will need to estimate the number of people aged 15 and 16 in this city. From table 3 these two age years are attached with the age years of 17-19 to give an estimate of the percentage of 15-19 year olds within this city. This time, we will not assume that there are an equal amount of people in each age year of this age group as the estimated percentage value for this age group was obtained by getting the average of seven UK cities where the latter ages of the age group were affected by people coming to work and study in these cities.  So, the number of people aged 15 and 16 is therefore going to be less than those aged 17, 18 or 19. Now, by first assuming there are an equal amount of people in each age year of the age group 15-19 and then decreasing the result by 10% to get a more accurate figure, an estimate of the number of people where secondary school level is compulsory to them is:




Now that we have the number of people in compulsory education, we will need to estimate how many there will be in each of the types of schools which they could attend as shown in Figure 2.  Our analysis for this is shown here:


· Special schools

In   January 2007 2.9% of people across all schools in England had statements of Special educational needs of which 36% of them attended special schools whilst the number of those without statements attending special schools was approximately zero. Therefore an estimate of the number of people in this city attending special schools is given by:


Number of people in all         × percentage of people              × percentage of people

Schools in this city                    with SEN with statements          with SEN with statements

                                                                                            attending special schools


As the percentage of people with statements of special educational needs, attending special schools below five was approximately zero in England in, their population estimate will not be taken into account when doing the above equation.            

An estimate of the number of people receiving further education at school in this city using the table is 180.


Other schools include:


·      Independent schools

·      Comprehensive schools


·  The number of primary school pupils (including 4 year olds) at each of the two possible schools they could attend at their age is roughly equal


A campus for a university for about 5,000 students will be built.


8.4 Hospitals


Currently, the number of beds per 1000 population in the UK is 4.1. Furthermore, the average space required per bed is 69m².  Since the proposed floating city accommodates 50,000 people, we need to have a hospital covering area of approximately 14,000 m². 


8.5 Marina


The distance of the waterline to the surface of the pontoon is considered to be the appropriate length of the ramp that provides a link between the marina and the pontoon structure. The angle of the ramp to the side of the pontoon must be safe for both tourists and yacht owners. Therefore, the larger the distance between the waterline and the surface of the pontoon, the longer the ramp must be and the further out the marina is from the edge of the pontoon. Therefore if this distance is similar to that of a ship's hull, then the ramp will have to be very long and may need to be supported by pillars sitting on the seabed. One method of preventing the marina from being so far out from the edge of the pontoon, due to the length and angle of the ramp to the pontoon side, is to replace one of the rectangular pontoon units positioned in front of the marina with a right angle triangular prism shaped pontoon which provides a route from the pontoon to the marina at its sloping side, see Figure10 below. Other than the marina, facilities for tourists (restaurants, shops, hotels, public car parking, etc) and yacht owners (yacht chandlery, boat repair shop, showers, changing rooms and lockers, outdoor boat storage area, marine supply and administration office, boat trailer parking need to be located alongside or near to it.  A breakwater will not be required for this marina, as there is already one around the pontoon.




Figure 11: Ramp between pontoon unit and marina.



Space and Size:

Marina: 240m×120m.

Associated facilities 360m×140m.


8.6 Recreation and Open Spaces

Open spaces and recreational areas such as parks, playing fields are needed in a city. Some of these areas will be used as venues for rugby, football, and cricket matches and may be home to some local sport clubs, whilst others may just include a garden with walkways and a children’s playground. New towns in Britain consist of 15-30% of open space[1].


Table 11 below shows the parks/open spaces, which will be included within this city and together cover an area of 2km².










Large area for picnics,  recreational activities and circus venues


720 × 300



Sport Centre –see table 3 in appendix for details

400 × 400


Town Park

120 ×150


Park with bowling grounds, field with foot paths and tennis courts

150 ×170


Cricket Pitch

100 × 120


















Table 11: Outdoor Leisure space


 8.7  Material of construction of 'Water Britain'


It is proposed that 'Water Britain' is constructed from an 'S' glass composite material or a similar material and not (say) from concrete.  This is because the the hydrodynamic forces that the structure will normally experience, will cause the structure to flex and some parts of the structure will go into tension.  Now, concrete is very weak in tension; according to Case et al, the strength of concrete in tension is only about 3 MPa, while its  strength in compression is about 30 MPa.  In contrast to this, the strength of high-strength glass-fibre is about 1600 MPa, or over 50 times the maximum strength of concrete,  Additionally, the density of concrete is about 2410 kg/m3, while that of 'S' glass fibre composite is about 2000 kg/m3, so reserve buoyancy of the structure will not be a problem. Furthermore, as 'S' glass composite has a high sound absorption coefficient, almost as good as that of an acoustic tile, less noise will be transmitted from adjacent dwellings constructed from 'S' glass composites, than in dwellings constructed from conventional materials on land. The houses will be built to good 'eco' standards, with good heating insulation in the walls and 'roofs'.  Additionally, solar panels will be embedded into the vast majority of the roofs to produce electrical energy locally.  Installation of the solar panels on the roofs should be easier than on conventional roofs because the roofs will be made of 'S' glass, which will be about 100 times stronger than conventional roof tiles. It is suggested that the structure is built in a modular fashion, where each module can be launched from its building berth and then floated to the site, where it will be assembled.  In general, roads will be constructed from hard wearing plastics or similar materials.


8.8  Drainage and Sewerage


As the structure is made from a composite material, drainage and sewerage systems will be less of a problem; these systems being of a 21st century design, unlike many British cities which are based on 19th century designs.  Flash flooding will almost be impossible and the roofing 'tiles' will also be constructed from composites, so leaking roofs will not be a problem and should last for much longer than conventional tiled roofs.   The sewage will be treated and pumped out to the open sea, about one to two miles from the structure.  Flooding  from tsunamis, hurricanes and earthquakes will almost  be  negligible.


8.9  Power


This will, in general, be in the form of electricity and will be supplied from the mainland.


8.10  Agriculture


The growing of vegetables will be possible if a new method of agriculture, invented at Epcot, USA, is adopted.  This method is called 'hydroponics'; the method does not require soil.  All the method requires is water, air, sunshine and nutrients.  The method can be used for growing cucumbers, tomatoes, lettuces, cabbages, turnips, beetroot, potatoes, carrots, maize, fruits, etc., etc.  The method is not really suitable for growing dense quantities of grass, etc., etc.  The method of 'hydroponics' may require gravel, rocks, etc., but not soil.  The method has the advantage that root crops grown by this method are less prone to root diseases. According to Dr. Howard R. Mesh, in his book on "Hydroponic Food Production", yields of cucumber  in conventional agriculture are normally about 7,000 lbs/acre, but this will rise dramatically to 28,000 lbs/acre, when grown hydroponically.   Similarly, the yields for tomatoes, when produced by conventional agriculture are about 5 to 10 tons/acre, but when grown hydroponically, yields are from 60 to 300 tons/acre.  Dr. Mesh also states that Canada consumes about 400 million pounds of tomatoes per annum and to produce this yield by conventional means, about 25,000 acres are required.  In direct contrast to this, if the same annual yield is grown hydroponically, only about 1,300 acres are required!   Hydroponic agriculture lends itself particularly favourably to strawberry growing, because as there is no soil for the strawberries to rest on, less 'soil damage' occurs to the strawberries, than when the strawberries are grown conventionally. Additionally, because of the more precise and regular spacing  between plants with hydroponic agriculture, it lends itself more readily to robotic control, thereby making the growing of crops less labour intensive and cheaper to grow and harvest.  It must be remembered that some countries are using bio-fuels to combat detrimental climate change, but the present authors would like to point out that the grain required to feed one adult for a year is roughly the same as the grain required to produce one tank full of ethanol fuel for a 4x4 motor car!  This is worsened by the fact that it takes about 10 lbs of wheat to produce 1 lb of meat and the problem is further complicated by the fact that the burgeoning middle classes of China and India are eating more meat than their less educated cousins!   Thus, we will need more land to grow food!  In general, lawns will be made from a material similar to "Astro Turf".


8.11  Hydrostatic Stability and Buoyancy


This will not be a problem, because the city pontoon is about 2.8 miles (4.5 km)  long and about 1.8 miles (2.9km) wide, and as hydrostatic stability is roughly proportional to the width of the pontoon squared; the metacentric height of the vessel will be huge; in fact its metacentric height will be in the region of 139,000 m!  Our calculations show the mass of the vessel will be about 65 million tonnes and its draft will be about 5 m.  Additionally, the vessel will be located in coastal waters, where the maximum wave height will not be particularly large.  Additionally, as the strength: weight ratio of the structure will be much higher than if it were constructed in concrete or steel, hydrostatic stability and buoyancy will not pose a problem.


8.12 Cost of Construction


If 25,000 dwellings are built at an average cost of about £300,000- per dwelling, the cost of the residential accommodation will be about £7.5 billion.  It is expected that the cost of the remaining infrastructure will be of a similar order to this, so the total cost of the island city will be about £15 billion.  If this is an underestimation of the total cost of construction of the vessel, one must remember that the cost of the international space station, in outer space, was about £53 billion, thus, the vessel is affordable, especially as much of the residential accommodation and infrastructure can be sold!.


8.13  Employment


Employment will usually be of the 'high-tech' variety or light industry, which will include design, electronics, computing, service industries, etc.


9.0 The City Layout


9.1 The City Centre

Town centres accommodate administrative, socio-political, cultural, educational, and commercial institutions on a national, environmental, city, or city district, and at regional level (town Centres Planning and Renewal). A planned city such as Milton Keynes was designed for a target population of 250,000 and its city centre covers an area of 2.15km² (0.83 mi2). Using a similar proportion, this will give the area of the city centre for this floating city of about 0.50km² (0.19 mi2).




Total m²




Library: in city centre


70 ×80




Cinema:2 screens



Museum: marine






University: 5000 students



Law Courts (magistrates)

Other court types: those in nearby cities could be used






Town Hall



Police Station



Post Office: branch



Tourist information centre




Bus and coach station














    9.2 The outline of the city

By using the space requirement stated above we can sketch a plan of the city and its city centre.



The City Centre




 The General City Plan





10.0 Conclusions


The paper has presented the conceptual design of a floating island city located anywhere in the world, but especially in the UK.  Several other existing designs have been discussed, together with the proposed design. In order to take this project further, it will be necessary to carry out an in-depth engineering analysis in sections such as; buoyancy and hydrostatic stability, together with structural strength, materials to be used, mooring, breakwater design, sewerage, agriculture, power supply etc., etc

Although at the moment, the idea of a floating island city may appear to be far fetched, it can be seen that already in the 20th century the application of floating technology has included the design of oil storage facilities, oil rigs, bridges etc.  Moreover, as more land will be required in the 21st century to feed and house a growing global population, the best way to accrue the additional land is by constructing floating island cities, because some 71% of the Earth's surface is covered by water. It will be necessary for mankind to colonise the seas in the 21st century!  It should be noted that due to some regional problems in land that is submerged in shallow waters, it might not always be possible to reclaim this land , using traditional land reclamation techniques. In these cases, the concept of a floating island city may be the best option available. Additionally, the advances made in the design and construction of large offshore structures, such as oil platforms, can be extended to the construction of a floating island city. Furthemore, the building of floating island 'cities' should prove of considerable military value, because the rising sea levels will pose a major threat to western military bases, as many of these will go underwater when the sea levels rise by 6.7 m (22 ft).

However, one of the factors, which might inhibit such a concept being realised, in the near future, is the vast amount of capital that will be required to carry it out; about £15 billion! It is very important to acknowledge that such an idea must be fully supported by the government of the day in order to come into effect. In any case, monetary figures of about $50 billion were mentioned on the BBC 2 TV programme, namely, 'Newsnight', on June 25th, 2008,  to overcome the problem of the forthcoming demise of western global military bases, due to rising sea levels.  Floating island cities will also be of interest to other crowded countries and countries that are likely to be flooded by the encroaching seas caused by global warming, together with those countries that are likely to be affected by tsunamis, earthquakes and cyclones.  In the UK, London will be an area where floating island cities may help to alleviate overcrowding.  In this case, floating island cities can be placed in the Thames' Estuary, off the coasts of Kent and Essex. It is suggested that for the present design, the pontoon base of the city, together with the buildings on top of the pontoon base, are constructed from high-strength, low-density composite materials, which are thoroughly water-proofed and can resist large dynamic forces.




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Paxman, Jeremy, Newsnight,  BBC2 TV, 25th June, 2008.


Appendix 1



Percentage of city population within each type of Household


One-person households

Married Couple Households without children

Married Couple households with children

Cohabiting Couple households

Lone parent households

All others (students, transients etc)





































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[1] Triton Foundation and R. Buckminster Fuller