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Working Group 1A - Comparison of Case Studies |
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Click
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Case
studyUtrecht GREEN STRUCTURE AND
URBAN ECOLOGY OF UTRECHT Sybrand Tjallingii -
Faculty of Architecture, Delft University of
Technology February 2003 1.
Introduction Urban green structure is
a new concept that points at the way urban green areas
connect to each other and to the urban structure as a whole.
In the 1980s, practitioners and researchers introduced the
green structure concept to discuss their analysis of green
network relations and to improve planning conditions for the
role of green areas in urban environments. In 2000, the
European Commission's initiative to stimulate CO-operation
in Science and Technology (the COST action programme)
provided an opportunity to start a COST action devoted to
the issues of green structure and urban planning
(www.map21ltd.com/COSTC11). The participants in the COST
action decided to have working groups for different aspects:
planning issues, human values and use and ecology.
Acknowledging the impossibility to strictly separate these
aspects in urban practice, we expect to throw more light on
the role of urban green structure if we look at it from
different points of view. The ecological viewpoint is the
basis of this case study on Utrecht. The meaning of ecology
is not self-evident. In municipal practice urban ecology
often refers to the study of wildlife in urban environments.
Yet, plants and animals are highly dependent on human values
and their protection or control requires planning. The
Ecology working group therefore decided to focus on
ecological processes: the physical processes that create
conditions for both urban residents and wildlife. Thus, the
ecological viewpoint is rather process-oriented than
object-oriented (Tjallingii, 2000). This leads to the
following questions that will structure the case study
report. 1. What are the elements
of the local green structure and how did natural and
cultural factors contribute to its present
pattern? 2. How is the urban
green structure related to local biodiversity? How green
structure may create conditions for enrichment? 3. How does the local
green structure relate to human health? What is the role of
pests? 4. How is urban green
structure related to local climate and hydrology? How may
green structure create conditions for
enhancement? 5. How are green
resources used and managed? What is the role of forestry and
farming? How does the local green structure relate to the
flow of organic matter? 6. What is currently
recorded about green structure? And how are monitoring
results used in evaluation studies? 7. What are the
objectives of green structure planning? How are these
objectives related to policy instruments? The second section of
this paper discusses the origin of the local green
structure; section 3 deals with the questions 2-6 and the
last question is the focus of section three. The case study is based
on the actor's active participation in several municipal
projects concerning water and green planning and the
management of public open space. For this report the
information was completed by an analysis of documents and
some interviews with key persons. 2. Origin and nature of
the Utrecht green structure This section analyses
the natural and cultural history of the network of green
areas that has been named the Utrecht green structure. After
an introduction to the landscapes of the Utrecht region, the
history of the city's green structure will be related to a
number of driving forces and transformation processes in
urban development. 2.1 Urban development
and landscapes Presently, the city of
Utrecht has approximately 250,000 inhabitants who live on a
surface of 91 km2. The Utrecht urban region has more than
half a million inhabitants and is a part of the Randstad
Holland metropolitan area. On the western edge of this urban
region is the so-called Green Heart, an open
meadow-landscape of approximately 50 km wide that is the
central part of the horseshoe of Randstad cities. To the
east, Utrecht borders on a wooded hill ridge pushed up by
glaciers in the ice age. South of the city, the big rivers
belonging to the Rhine delta dominate the open meadow
landscape. West and north of Utrecht the rivers used to meet
the sea and the resulting stagnant waters created big swamps
where thick layers of peat could develop. From the Middle
Ages till the nineteenth century, peat provided fuel for the
early industrial development in the cities. In the
beginning, the land was still dry and peat could be cut from
the surface. Later the pits filled with water and dredging
was the only way of peat mining. The result is a landscape
of lakes north of Utrecht. To the west the rivers deposited
clay on the peat layers. The basis of these different
landscapes is in their geology and soils: glacial sands to
the east, peat in the northern and western polders and river
clay to the south. A long cultural history has transformed
this rough basis into a rich variety of green areas. Apart
from the northern lakes, where recreation is the leading
activity, most of the green land is still in agricultural
use. But urban land-use is rapidly taking over. Figure
1. Landscapes of the Utrecht region. The map shows the
rivers, running from east to west. The brown coloured areas
to the east are woodlands. To the north, a landscape of
lakes is visible. All the white areas around the city are
meadows. The traffic network is in black and the water
network in blue. The map further shows the red 3-kilometre
distance line and the circle, which indicates the
10-kilometre distance from the built-up area. (source:
Gemeente utrecht, 2000). 2.2 The green structure
of streams The first and most basic
process that structures green areas in the city is the
meandering of rivers. De Bruin, van Dam and Wassink (1988)
edited a rich description of this history. The origin of
Utrecht's spatial structure goes back to the Romans who
founded the city two thousand years ago at a point where
they could cross the river Rhine. The name Utrecht is
derived from Ultrajectum, the last bridge. In those days it
was a real effort to cross the river that was the northern
boundary of the Roman Empire. In the centuries that
followed, the river Rhine transferred the bulk of its flow
to more southerly channels. In the middle ages the Utrecht
branch of the Rhine was cut off from the main stream. The
tamed river became a more convenient waterway and the high
banks that used to protect the city from the floods lost
their function. Merchants used the high banks to build their
warehouses and workshops. Today, there is only a small
stream called Kromme Rijn, that meanders through the city
where it splits up in two: the river Vecht goes north
towards the old Zuiderzee, the sea near Amsterdam and the
Leidsche Rijn flows to the west to reach the North Sea near
Leiden. These three, together with some smaller parallel
branches are the network of streams that shapes the urban
street pattern. The rivers in the inner city, the Oude
Gracht and Nieuwe Gracht, have a high road and a low road
with trees. Pedestrians can walk down the stairs and sit in
the outdoor cafés and restaurants that now have taken
over the occupation of the old high bank warehouses.
Richness in the details of nature and culture, like wall
vegetation and sculptured lantern consoles, contribute to
the typical Utrecht river profile that is not found in any
other Dutch city (figure 2). Figure
2. River branches have shaped the old city. The maps show the old
meanders of the river and the present street pattern. The
cross section shows the typical profile with the two levels.
In the surrounding
countryside towpaths accompany the Kromme Rijn, Leidsche
Rijn and Vecht rivers. Once used to pull vessels, they now
are footpaths that offer nice walks with beautiful views on
the water and on the estate parks that were planted along
the river by well to do citizens in former centuries. Parks
accompany the rivers in the outer parts of the city and in
the inner city trees line up along the waterways and turn
them into greenways (figure 3). Figure
3. The green structure of streams. River branches shape the
urban green structure and link the inner city green areas to
the surrounding countryside. 2.3 The green structure
of defence works the walks of Jan David
Zocher The second process that
has structured green areas in Utrecht is the history of
defence works that have been transformed into parks. In the
seventeenth century, the medieval brick walls were
reinforced with earthen walls but, soon, also these renewed
defence works could no longer resist the enemy's
cannonballs. At the beginning of the nineteenth century, new
fortresses built outside the city made the old city walls
redundant as defence works. Moreover, the old walls were
felt as a brick corset (Zijlstra, 1988: 32) for the growing
population of city. The city needed new space for further
growth. What was left of the ramparts and towers had turned
into a messy edge area and the city council felt it was
necessary to improve the image of the city in order to
attract wealthy merchants and give a new incentive to
economic development. The large number of unemployed and
poor citizens would also benefit from this development. In
1827 the council decided to demolish the old walls and
replace them by a park. The task to design the new walks was
given to the famous landscape architect Jan David Zocher,
who had performed a similar task in Haarlem and who, later,
would become the designer of the Amsterdam Vondelpark. The
brick walls were demolished and the earthen walls were
turned into little hills. Thus, Zocher created an excellent
starting point for a beautiful English Landscape style
design that was realised in the years between 1830 and 1860
(Becker-Jordens & de Vries, 1973). Today, the Utrecht
citizens speak about the Singels, referring to the walks
along the water, surrounding the inner city. The singel park
is a very popular walk for many residents and visitors of
the inner city who enjoy the old trees, nice views, a rich
bird life and, in spring, beautiful bulbous plants (Bals et
al. 1988). the Holland Water
Line The Lowlands provide an
opportunity to use water for a common defence of the cities.
The first chain of inundation areas, the so called Utrecht
Water Line, was an improvised project in 1629, when the
Dutch fought for their independence against the Spanish
(Will, 2002:30). Later, this idea developed into a planned
strategy that included the inundation of a network of
polders ranging from Amsterdam to the southern branch of the
River Rhine. Together, this network could protect the whole
of Holland. In the late seventeenth century, the Republic
built a chain of fortresses, sluices and inundation canals
to make this system operational in case of emergency. This
Old Holland Water Line was situated west of Utrecht and did
not protect the city. Two centuries later, however, the New
Holland Waterline included the defence of Utrecht by a
series of inundation works and fortresses on the eastern
side of the city. The first fortresses have been built from
1815 &endash; 1826. By the end of the century, improved
cannons required defence works at a greater distance from
the city and this led to a second chain of fortresses. For
military reasons, the area with the fortresses in the
eastern and north-eastern fringe of the city stayed green
until 1948 (Will, 2002:124). Therefore, the city first
expanded to the north and the west and it lasted until the
1960s before that urban growth took place on the eastern
side. Here, building activities included two residential
districts and the new university campus but the fortresses
stayed green and became the carriers of the urban green
structure. Because of their military function the public had
no access to the fortifications and this contributed to
their rich wildlife, as biologists discovered later (Maes,
1984: 27). In the last twenty years, some fortresses have
been turned into public parks, whereas others are now
protected areas. Figure
4. The green
structure of defence works. Old fortresses and
bulwarks are the carriers of green structure around the
inner city and in the eastern part of the city. 2.4 The green structure
of public parks In the Middle Ages, the
citizens of Utrecht could walk on the squares and courtyards
of churches, monasteries and castles. These places used to
be planted with elms and lime trees. After the Reformation
also the cloisters opened their courtyards to the public and
people could enjoy their herbs and fruit trees. Many of
these public green spaces still exist in the inner
city. The first public
recreation area originated in 1637. At the time, students of
the university, which was founded the year before, liked to
play a game with sticks and balls, the malie game (mall
game). The council wanted to keep the city attractive for
students and decided to create the Maliebaan, a one
kilimetre long green alley with six rows of trees that was
made for the game but soon became an attractive walk for
many citizens (Bongers et al. 1988: 10). It lasted until the late
19th century before municipal parks were felt to be a real
need for the city. In 1888, inspired by the success of the
singel walk around the inner city, the council decided to
have a competition for a new public park east of the city
centre. The result was the landscape-style Wilhelminapark,
named after the queen in that period. This park became the
attractive centre of the new developments between the
working class districts and the urban fringe with the water
line fortifications. Gradually, the establishment of public
parks became a regular feature of urban development, and the
first places chosen were old country estates with gardens
that became part of the growing urban area. Between 1880 and
1940, six smaller country estates were turned into public
parks and in 1962 the municipal council bought the larger
estates Old and New Amelisweerd, forming a green area of 200
hectares stretching for almost three kilometres along the
Kromme Rijn river. This park was to become the most popular
of Utrecht's parks with well over a million visitors per
year. The next step in the
history of urban green areas was the design of new parks as
a part of new residential developments. The city has grown
in a concentric way. The big medium-rise apartment-buildings
of Kanaleneiland and Overvecht were built in the 1960s. In
the 1970s and 80s a landscape oriented design resulted in
the low rise Lunetten district. The river Leidsche Rijn has
given its name to a big new urban district that is now under
construction. Here, 30,000 new dwellings will be built and
the same number of jobs created. Together, these districts
generated a new generation of public parks. With the
exeption of the Leidsche Rijn central park, most of these
new green areas are islands of green. Until now, they are
not connected by green ways. Between 1950 and 2000
urban planners also further completed the green structure of
rivers and fortifications, taking advantage of the
opportunities in different parts of the city. One of these
opportunities presented itself on the site of an old
gasworks area along a river branch near the inner city. In
the nineties, financial support made available for the
clean-up of contaminated soils paved the way to create the
Griftpark. Figure
5. The green
structure of public parks Together, the public
parks create a structure of spots rather than a network.
2.5 The green structure
of transport networks The construction of
waterways, railways and motorways has had a major impact on
green areas in the Utrecht area. Once the ships from
Amsterdam went through Utrecht on their way to the east. The
improvement of waterway connections between Amsterdam and
Germany, however, led to the construction of the Merwede
canal (opened in 1892). Half a century later, this canal had
to be replaced by the larger Amsterdam-Rhine-Canal (opened
in 1952). In the western part of Utrecht a section of the
old canal survived. The canal banks provide a green way that
is attractive for cyclists and pedestrians, but its
technical design does not create interesting new habitats
for wildlife. The railway verges demonstrate the opposite.
They do offer excellent habitats and corridors that
contribute to the ecological network. Cyclists, however,
usually prefer other green ways. The motorway verges are not
so special, whereas the motorways themselves create serious
barriers between green areas and between the city and its
surrounding landscape. In 1981, the construction of the A 27
motorway cut the Amelisweerd estate park in two and this
event is seen by many as one of the tragedies of recent
urban history. Figure
6. The green structure of transport networks Waterways and railways
add new green ways to the existing green
structure. 3. Green structure and
urban ecology This section first
discusses the way urban green structure creates conditions
for biodiversity. Then, there will be some remarks about
health and recreation. Together, these issues represent the
ultimate goals of green structure policy. Besides the urban
ecology of goals, however, there is also the 'ecology of
means' about the use of local resources for many cultural
and economic qualities of urban life. In this context, the
section discusses the management of water resources and the
maintenance of green areas. 3.1 Green structure and
biodiversity biodiversity of
Utrecht Surveys in the 1970s
revealed that the flora of the city of Utrecht and its
immediate surroundings counts approximately 700 species of
native plants, about half the total number for the
Netherlands (Farjon et al. 1987: 77). Taking into account
the presence of rare species in nature reserves in rural
parts of the country, this number is high. In comparison
with the 938 species found in a survey of the Province of
Utrecht (approximately 2000 km2), the 700 of the city
(nearly 100 km2) demonstrate the richness of the urban
ecosystem (Provincie Utrecht, 1984:168). The number of bird
species breeding in the city is 93, of which 46 feel at home
in the built-up area. Several groups of amateur biologists
have collected data about other organisms, such as
butterflies, amphibians and reptiles. These surveys do not
cover the whole of the municipal territory, but they provide
excellent information for the protection of these species
and for the improvement of their habitats. In different ways urban
green structure creates conditions for biodiversity.
surface and use of green
areas as a condition for biodiversity A first condition is the
surface of green areas. According to city statistics, the
total territory of the Utrecht municipality is now
approximately 100 km2. The built-up area covers about 70 %
of this area, agricultural land takes 24%. Roads take 4 %
and only 2 % is forest. These figures, however, do not say
much about the opportunities for wild plants and animals. On
the one hand, the built-up area figure hides parks,
cemeteries, private gardens and street trees. On the other
hand the figure for agricultural land refers to green house
horticulture and other intensively used farmlands that do
not offer any opportunity for wildlife at all. To describe
the interesting habitats, we need other
categories: 1. places with tolerated
spontaneous plant growth such as: walls, derelict and fallow
land, road verges, railway embankments and railway yards.
2. planted and
cultivated areas like alleys, allotment gardens, sports
fields, cemeteries, private gardens, parks and public
gardens. 3. protected natural
areas like fortresses, wet meadowlands, willow coppice and
estate parks (Farjon et al. 1987: 78). maintenance level
categories and biodiversity Within the public parks
and gardens, the maintenance level of green areas is
important. The green areas management department uses a
typology of maintenance categories for public green areas
that is shown in figure. 6. Figure 6. Maintenance
types of public green areas Best conditions for wild
plants and animals are found in the rough woodlands and
rough grass categories. As maintenance costs are low for
these areas, their surface increased in the 1980s, a period
of budget cuttings. In residential districts these
categories of green areas met with resistance. Wild was seen
as the result of neglect and in socially problematic areas
the wild bushes were soon perceived as unsafe. This led to a
preference for higher maintenance levels within the
districts. In areas between the districts, where the main
green structure is concentrated. Here, it is therefore
easier to create conditions for natural plant and animal
life. Here we find the larger green areas where biodiversity
can develop, not because of neglect or budget cuttings but
as a result of ecological maintenance practice. ecological corridors and
biodiversity Connecting corridors
between green areas are vital for crawling animals and for
the dispersion of seeds they carry with them. The role of
green corridors therefore has become an important issue for
urban ecologists. In their preparatory study of the Utrecht
Green Structure Plan Farjon et al. 1987: 87. point at the
following dispersion zones requiring attention in planning
and maintenance: 1. river zones of Kromme Rijn, Leidsche
Rijn and Vecht and adjacent green areas; 2. railways and
adjacent areas; 3. water courses with unpolluted water; 4.
ecological corridors situated along pedestrian and cycle
tracks in gradient areas between different soil types and 5.
a zone along the Amsterdam-Rhine-Canal that is used by
migrating animals in north-south direction. All of these
corridors are linked to the main urban green structure. The
regional authority of the Province of Utrecht established a
method of biotopes and ecological groups with a guiding
organism as a basis for ecological corridor planning (Van
Arkel et al. 1993: 95). The municipal green areas department
further elaborated this approach and generated maps for six
ecological groups, indicating the desired corridors and a
number of activities to remove constraints and improve
conditions (Oost et al. 1999: 39). abiotic conditions for
biodiversity Corridors only create
ecological conditions for biodiversity if they connect
habitats. Habitat qualities related to abiotic factors like
soils, ground water and surface water play a key role in
this context. Gradients at the landscape level between high
and low, dry and wet, sand and clay, create a frame for
diversity. One of the key factors is upward seepage of
groundwater in the north-eastern part of the city where the
sandy soils of the Utrecht Hill ridge are covered by thin
layers of clay and peat. This area is a potential source of
clean, nutrient poor water. Interesting gradients at
the scale of railway verges have been introduced by the use
of nutrient poor sand for construction. Nutrient rich is the
dominant feature of the urban environment and of the
agricultural land on the clay and peat soils around the
city. Therefore nutrient poor introduces ecologically
interesting gradients. The gradient between dry
and wet conditions on each riverbank and along all other
surface waters asks for detailed design and nature friendly
banks therefore have become a regular part of habitat
creation programmes in all parts of Utrecht. green structure as a
basis for present and future biodiversity Most of the above
mentioned ecological conditions may enhance biodiversity if
they are made manifest in the green structure levels
discussed in section 2: the rivers, the defence works around
the inner city and in the urban fringe, the larger parks and
the railway tracks. This implies that the urban green
structure creates the vital conditions for the preservation
and development of biodiversity. 3.2 Green structure,
health and pests Research about the use
of green areas in Utrecht revealed that 65-86 % of the
residents of different urban districts frequently visits a
park and 67-87% frequently visits a recreation area outside
the city (Hinssen 1993: 27). The Wilhelminapark in the city
and Amelisweerd, just outside the city, both attract
approximately one million visitors per year. The inner city
parks and the outer green areas are not exchangeable
(Hinssen 1993: 24). People love them for different reasons.
A direct cause and effect relationship between the presence
of green areas and human health is difficult to prove but in
general terms the healthy effect of outdoor activities in
green areas is clear (Van den Berg & van den Berg 2001).
The history of the
Griftpark is a paradox in this context. The highly
contaminated soil of the old gasworks could not be
completely purified. Therefore the area was considered too
unhealthy for residential development. As a result, a
beautiful park emerged in the heart of the city: unhealthy
in case you would grow fruit trees and eat the apples; very
healthy, however, for the stressed office workers looking
for a quiet park to have their lunch. Recently Van Bronswijk
(1999) pointed at the risk that more natural ecosystems in
urban areas could improve conditions for rats and
mosquito's. She even warned for a possible revival of
Malaria as a result of climatic change combined with the
presence of natural wetlands in Dutch cities. The reaction
from experts in the fields of entomology, epidemic and
tropical diseases was clear: there is no evidence of such a
threat (Takken et al. 1999: 836). The opposite is more
likely. If green structure is to be developed for a number
of activities, than, investment in environmental measures to
improve water quality is a logical step. Thus, in the last
twenty years, Utrecht invested in the connection to the
sewer system of old houses along the Oude Gracht, the
central green and water axis through the city. As a result,
there was a remarkable increase of oxygen in the water and
this, off course, contributed to all the activities related
to the Oude Gracht system. 3.3 Urban water and
climate More natural ecosystems
can also play their role in improving water quality and the
introduction of the wetlands as a part of the urban water
system is a good illustration of this ecology of means. Here
it is not an ecological goal like biodiversity that asks for
means, but it is the multifunctional goal of creating good
water quality that asks for ecological means. The new
Leidsche Rijn development will have a surface water system
in which water circulates from the built-up area into a lake
in the adjacent green lobe that is part of the urban green
structure. Here, the water will pass through the wetland
that will care for sedimentation and nutrient uptake. The
purified water will then recirculate into the built-up zone
(Spangenberg, 1995). The role of green areas
and street trees in moderating urban climate is clear in
general terms, but apart from some incidental discussions
about the need for a windbreak for cyclists, climate is not
an issue in Utrecht, nor in other Dutch cities. 3.4 Use of green
resources In the built-up area of
Utrecht approximately 150 hectares of green area are being
used as allotment gardens. Agriculture, most of all dairy
farming on meadowland, used to be the dominant land use of
the green areas around the city. In 1985 there were still 47
farms, but many of them were small hobby farms with part
time farmers (Wieringa, 1987: 19). Full-time farmers
increasingly face the need to industrialise and expand their
enterprise and this is extremely difficult in the urban
fringe that is full of uncertainties about urban expansion.
Several zones in the western and eastern Utrecht fringe area
are not yet urban and no more rural. The process of
urbanisation is more than the building activities. In recent
years, the rural perspective of a landscape produced by
agriculture changed into an urban perspective where planners
and politicians speak about urban landscape consumers who
have their preference for green area quality. In this
process of change the economic question is whether these new
consumers are really prepared to pay for the green landscape
they enjoy. Can the Green Heart become a Central
Park? One approach is the
Noorderpark, a 5,700 ha rural area just north of the city.
The area is part of the Randstad Green Stucture scheme that
aimed at creating larger green recreation areas situated
between the agglomerations of the Randstad Holland (van der
Cammen & de Klerk, 1986:304). It was this planning
document that introduced the term Green Structure to the
Dutch spatial planning vocabulary in the 1980s. The Randstad
Green Structure Scheme has a project budget and operates
under the legislation of the 1975 Relation Memorandum rules
that deal with payment for farmers who fulfil landscape
maintenance tasks. A different approach is
chosen for the Amelisweerd area, where the municipality owns
the land and leases it out to local farmers. In this way the
landscape can keep its qualities for human visitors and for
wildlife, and at the same time its resources are used by
farmers. 3.5 Surveys and
monitoring Utrecht has a long
tradition of experts who have initiated important ecological
studies about nature in the city. A working group of amateur
ecologists - with the long name Working Group for the
Restoration of the Quality of Life in the Old Districts of
Utrecht - explored the ecological treasures of the city in
the seventies and eighties. They published detailed studies
about green areas in and around the city (Werkgroep Herstel
leefbaarheid Oude Stadswijken Utrecht, 1997; Ministry of
CRM, 1982, Maes, 1984). In the preparation of the 1990 Green
Structure Plan, Farjon, Harms and Scheffer (1987) carried
out the first systematic analysis of present and potential
plant and animal life in the city. In the 1990s, the focal
point of green structure planning shifted towards improving
and establishing ecological corridors. This political
priority stimulated a number of studies that concentrated on
opportunities and threats to ecological pathways (Oost et
al. 1999). The resulting project implementation plan
(Gemeente Utrecht, 1977) included a monitoring task per
project. This will lead to a better understanding of the
impacts of interventions and maintenance practices. The
municipal department has no staff to do systematic surveys,
but private organisations are very active in parts of the
city. This is the case of the group that has taken care of
maintenance and monitoring of the Bloeyendaal park on the
east side of the city. Prior to every major
building or construction project the green areas department
carries out an ecological survey. 4. Green structure
planning in Utrecht This section reports
about a special case study on Green Structure Planning. It
starts with a description of the planning issues. Then the
1990 Utrecht Green Structure Plan will be analysed and the
final part discusses the issues in a wider perspective.
4.1 Green Structure
Planning the issues In the Netherlands,
Green Structure Plans (GSPs) emerged in the 1980s as a
sectoral planning instrument used by municipal parks and
green areas departments. Previously, urban parks, woodlands
and graveyards had been treated independently as separate
areas and policy documents on open spaces concentrated on
the quantity and distribution of the city's green areas. The
new approach introduced by GSPs treats these areas as a
coherent green network and emphasises their quality and
structure. At the end of the 1980s the ministries
responsible for urban green areas and urban development
jointly published a brochure that defined the Green
Structure Plan as follows. "A coherent package of
objectives, principles and priorities for the desired
quality of green areas in the public domain throughout the
whole municipal territory, leading to proposals for
sustainable development, with agreements about shared
responsibility and finances." (Meeus, 1989). Clearly, the
GSP is a strategic plan based on a consensus on the main
policy direction. The strategic plan aims to structure and
guide the development of operational plans for concrete
physical interventions in the urban landscape. Several issues
contributed to the emergence of this structural approach to
green area planning, each leading to hypotheses about the
role of green structure planning as a tool. This paper
explores and discusses the questions arising from these
hypotheses. The first issue is
whether green structure planning is a tool for defence or
integration. Increased competition for land within the
cities and in urbanising regions creates conflict, which is
described as a battle between red and green. Private and
public actors in the fields of housing, commercial
development and public buildings &endash; the red functions
&endash; tend to dominate at the expense of the green
functions such as agriculture, forestry, recreation and
nature conservation. Actors in the green sector consider
themselves to be the weaker party and feel the need for
defensive or even offensive strategies. The hypothesis is
that GSPs will strengthen the role of green areas in urban
development because they provide a structure for the network
of green areas. The question is whether the tool operates as
a defensive tool &endash; or possibly even an offensive tool
&endash; or that planners use it as an instrument for
integrating green areas into urban development. This leads
to the second issue, the potential synergy between green
area planning and other fields of planning. The second issue
concerns ecological networks, traffic and water. Since the
early 1980s, biologists have stressed the importance of
ecological networks of habitats, corridors and stepping
stones for the survival of wild species, and these networks
have become the cornerstones of nature policy at the
national and regional level. The hypothesis is that GSPs can
help to bring nature back into the heart of the city. In a
reaction to the domination of the car in urban development,
pressure is growing to develop networks of routes for
pedestrians and cyclists. Riverside parks and other linear
green areas provide a natural basis for these greenways in
the urban landscape. The hypothesis is that green structure
planning and the planning of walkways, cycle paths and
bridle paths are natural allies. In the field of water
management, valleys and river floodplains play an important
role in stormwater storage and flood prevention and in many
cities these areas are already part of the existing green
structure. The hypothesis, therefore, is that it will be
easy to develop joint strategies for water planning and
green structure planning. The question is how a GSP creates
links with planning for nature, water and traffic and how
this influences the role of green areas in urban
development. The third issue concerns
strategies and budgets. One of the reasons for making GSPs
is the perceived weak position of green functions in
budgetary negotiations. In contrast to buildings, green
areas rarely generate direct profits for private investors
and public sector investment in green areas can be a risky
business, too, because cities rely on the income they can
obtain from selling real estate to developers. In periods of
economic downturn or recession, as experienced in the 1980s
in the Netherlands, budgets for creating and maintaining
green spaces shrink. The hypothesis is that a GSP lists the
priorities for survival in times of financial difficulty
because it defines the backbone of the city's green areas.
The question is how GSPs are linked to investment strategies
and maintenance budgets. This leads to the fourth
issue, that of structure planning and projects: the links
between the strategic GSP and operational projects.
Individual green area projects may not form a coherent
whole; the essence of a GSP is to reach a consensus on the
creation of a coherent structure of urban green areas.
However, strategic plans such as GSPs tend to be rather
vague and may not lead to action on the ground. The
hypothesis is that a GSP will improve the conditions for
developing a coherent package of projects. The question is
how a GSP can perform the critical role of building bridges
between a strategy and actual projects. approach of the case
study and The Utrecht case study
that forms the basis for this paper resulted from the
author's involvement as a researcher and consultant in
several projects in Utrecht (de Jong et al., 1992;
Tjallingii et al., 1995). The analysis of green structure
planning in Utrecht is based partly on a more recent case
study carried out as part of the GREENSCOM project, an EU
Fifth Framework research project (Aalbers et al., 2002). The
picture was completed by a literature study and interviews
with key actors. Utrecht is an interesting case for
explorative research into the role of green structure plans.
Firstly, because the battle between red and green has at
times been dramatic at times. Secondly, because the city
made its GSP in the late eighties and followed this up with
a series of other strategic and operational plans, which
makes it possible to analyse the impact of the planning
instrument over a period of time. In general terms, the
analysis fits in with the methodology for case study
research described by Yin (1994). As a GSP is a strategic
plan, it only provides guidance for subsequent operational
plans. This implies that a GSP case study requires a format
that differs in some respects from the outline suggested for
operational plans by Francis (2001:20). Section two describes
the main features of landscape and urban development in
Utrecht and the planning history of the GSP. Against this
background, section three places the issues and hypotheses
in a wider perspective. The concluding discussion argues
that the problems do not require defensive or offensive
strategies but rather an integrated approach. Figure
7. The 1990 Utrecht Green Structure Plan. The map shows many green
structures as the different layers represented in the
figures 2 &endash; 6 are brought together in one map with
planning information. Dotted lines indicate planned
greenways. Figure
8. The Singel
Restoration Project From left to right: The
logo of the project; the map showing the missing link in the
Singel green structure; the cross section design; a part of
the singel after reconstruction. 4.2 The Utrecht green
structure planning experience the context of landscape
and urban development in the Utrecht area The city of Utrecht has
approximately 250,000 inhabitants in an area of 91 km2. The
Utrecht urban region has more than half a million
inhabitants and is a part of the Randstad Holland
metropolitan area. Utrecht is a river city.
The Romans founded the city at a point where they could
cross the river Rhine. The main channel of the Rhine now
lies further south and the remaining Kromme Rijn is only a
small river. It meanders through the city, where it divides
to form the river Vecht, which flows north, and the Leidsche
Rijn, which flows to the west. The land to the west and
north of the city consists of meadows on peaty soils, to the
north-east lies a Pleistocene sand ridge covered by woodland
and suburbs. But it is the river that shapes the urban
street pattern and green structure. Like many Dutch towns,
the inner city is surrounded by water and old
fortifications. In the nineteenth century these were
transformed into a narrow park and walkway, called the
Singel, which is now an important element in the urban green
structure. In the late nineteenth and twentieth century, the
green structure has been further enriched by a number of
public parks. To the west of the city centre, the map of
Utrecht also shows the old and the new shipping canals, that
link Amsterdam to the Rhine. The city has grown in a
concentric way. The Leidsche Rijn river to the west has
given its name to the latest large new urban extension now
under construction. This new district will contain 30,000
dwellings and there will be space for industrial estates
that can create the same number of jobs. Given its central
position in the country, Utrecht has become an important
road and railway junction. The green planners and many
residents suffered a traumatic experience when, in the early
1980s and after a battle of more than ten years, a new
motorway was built to the east of the city, cutting right
through the woodland of the popular Amelisweerd estate.
Here, indeed, urban development was the enemy of nature.
Another major project that deeply divided the community was
the enormous Hoog Catharijne shopping centre. A huge area of
the existing city and part of the beautiful Singel had to
give way to dynamic modern life. This turned out to be so
dynamic that just thirty years later this megaproject
already faces a megachange. Paradoxically, plans for the new
project include excavating the part of the Singel that had
previously been filled in. the 1990 Green Structure
Plan: defence or integration? The Utrecht Green
Structure Plan for the city was published in 1990. Figure 1
shows part of the GSP map. The green areas department
launched the GSP as a sector document; other municipal
departments played only a marginal role in its development.
In the introduction to the GSP the authors mention the
alarming economic situation as the main reason for
publishing the plan (Gemeente Utrecht, 1990:4). The plan
applies standards for the minimum amount of green area in
square meter per person to describe the shortages and
surpluses of green areas in different parts of the city.
Given the difficult financial situation, the plan proposes
overcoming the shortage in some districts by improving
connections to existing green areas, especially for cyclists
and pedestrians. A defensive attitude was
also adopted in discussions with the regional planners. The
GSP argues for a green belt around the city to contain urban
development, but the provincial planners were in favour of a
lobe structure of urban expansion interspersed with green
wedges (Gemeente Utrecht, 1990: 46). Following the efforts to
quantify the surplus and shortage of green areas in the GSP,
the green areas department commissioned new studies to
quantify the value of green spaces (Hinssen, 1992). Further
studies (Gemeente Utrecht, 2000) tried to collect
quantitative data on the demand for green spaces of
different qualities and sizes in the Utrecht area, but these
methods have still not been operationalised. Moreover,
focusing on hard figures to underpin the sector's interests
did not create a climate of cooperation with other
departments. potential synergy:
ecological networks, traffic and water Although other
departments of the municipal council have formally referred
to the GSP, there have been no significant joint planning
efforts. Opportunities for synergy between other planning
activities and green structure planning, for example with
the Bicycle Memorandum (1992), the Memorandum on Sustainable
Building (1993) and the second Environmental Policy Plan
(1993), were lost. The spatial planners, though, did do
justice to the GSP by explicitly mentioning in their 1995
Spatial Structure Vision that "the green structure should be
improved by making the surrounding landscape more accessible
from the city" (Gemeente Utrecht, 1995: 17). The realisation
of the Utrecht bicycle network was certainly aided by these
supportive policy plans. Efforts to combine the
green structure and the water structure have been less
successful. A study initiated by external consultants
proposed the creation of a coherent water and green
structure linking the city to the upstream Kromme Rijn
landscape and giving green spaces an important role in
rainwater retention (de Jong et al., 1992). These ideas met
with scepticism among the provincial and municipal water
officials, who were not prepared to relinquish their
traditional view that quick removal is the best way to deal
with rainwater in urban areas. The green areas department
itself made more specific recommendations on water
management in their 1995 report on the options for the
sustainable management of public open spaces (Tjallingii et
al., 1995: 56). At that time, the recommendations were
shelved. A few years later the water management officials
finally came round to the idea, but by then the green areas
department had already adopted another theme: biodiversity,
or urban nature. In 1998, the green areas
department published a Policy Framework for Urban Nature
(Gemeente Utrecht, 1998) which introduced urban nature as
the overarching principle of green structure planning. The
1990 GSP had hardly mentioned ecological corridors, but now
the policy makers started to define the green structure as
the spatial structure of the Ecological Network (Gemeente
Utrecht, 2000:4). The successful policy for the National
Ecological Network, launched in 1990 by the Ministry of
Agriculture, Nature Management and Fisheries (Ministerie
LNV, 1990), proposes corridors and stepping stones to allow
plant and animal species to migrate between habitats. A few
years later, the provincial authorities drew up plans for
the regional network (Provincie Utrecht, 1993) and the
municipal council followed suit. As the local ecological
network became the key issue, green structure planning
became more sectoral than ever. Surprisingly, but also
logically, green structure planning, for the first time,
began to adopt an offensive role. financial basis:
strategies and budgets The strategic 1990 Green
Structure Plan, which was intended only to create a
framework for concrete operational projects, had no budget
allocation and depended on other programmes for the
realisation of its proposals. This was not uncommon for
strategic plans, but in the years that followed the weakness
of this construction became apparent. In the 1990s the
economy picked up again and the municipality managed to fund
a sound implementation programme for green areas and linked
this to the 1998 Policy Framework for Urban Nature. Later,
the government ministries responsible for green areas and
urban planning launched a joint investment programme for
green areas in and around the cities as part of the national
urban renewal programme (Ministerie LNV & Ministerie
VROM, 1999). This further encouraged the parties involved in
green areas in Utrecht to cooperate (Gemeente Utrecht,
2000). Maintenance budgets,
too, benefited from the favourable economic climate, and
committed and active residents also helped to maintain green
areas. At the neighbourhood level, the city council
introduced maintenance contracts between the municipality
and groups of residents (Aalbers, et al. 2002:58). Currently
there are about 600 of these contracts, under which
residents do the work and the municipality provides a modest
budget, practical support and advice. These contracts are a
product of the district-oriented approach that has evolved
in many Dutch cities since the 1980s. green structure planning
and green projects In the early 1990s, the
GSP did not play an active role in creating suitable
conditions for project implementation. Nevertheless, Utrecht
has realised some spectacular green projects during the last
ten years. One of these is the Griftpark, the site of an old
gasworks near the city centre, which has been converted into
a beautiful park. A brownfield changed into a green area.
National funds from soil remediation programmes provided the
bulk of the huge sum required to transform this derelict
land into a healthy park. Another fine example of
a green project in the heart of the city is the Singel
restoration project mentioned above. The project description
does not mention the Green Structure Plan, but the project
website includes the GSP map, which illustrates a convincing
argument for restoring the missing link in the Singel (see
Figure 2). A larger&endash;scale
project is the masterplan for the new Leidsche Rijn urban
extension, which is evidence of a revival of integrated
green structure planning (Spangenberg, 1995). The
multidisciplinary project team for the new development
emphasised sustainable urban development issues and gave
green areas an important role in the design for the new
urban area. The centrally located park is connected to the
urban fringe and an old country estate by green fingers that
reach out between the neighbourhoods. The close relationship
between landscape and water planning became a landmark in
this emerging field of planning. More recently, local
government officials have started to use the updated green
structure map in negotiations with national and regional
governments on funding new green areas and regenerating
existing areas (Gemeente Utrecht, 2000). 4.3 Discussion
defence or
integration The Utrecht case
illustrates the shift in attention from individual green
areas to green networks. The change of emphasis towards
spatial green networks is a general trend among the 18 Dutch
municipal GSPs included in a survey by Meeus et al. (1989).
This trend is not limited to the Netherlands; a similar
change was found in the approach to the green zones central
to the transformation of the German Ruhr area (IBA
Emscherpark, 1992). Turner (1992) demonstrates the same
trend in the plans for green open space in London and
describes it as a shift from standards per 1000
(inhabitants) to green strategy. Previous reports, he
argues, have focused on the quantity and distribution of
open space. In the new approach the emphasis is on the
quality of open space and on its structural role (Turner,
1992: 385). Obviously, the authors of the Utrecht GSP were
reluctant to point to the spatial structures themselves as
an indication of the value of green spaces and commissioned
further research to quantify their value. This may be a
reflection of the defensive attitude that dominates the GSP.
Repeatedly, the GSP text speaks of "protecting green areas
from urbanisation as far as possible" (Gemeente Utrecht,
1990: 7). Even in recent interviews, planning officers from
the green areas department are sceptical and defensive:
"Although the importance of green areas in urban situations
is recognised, other interests often play a more important
role" (Aalbers et al. 2002: 98). The 1998 Policy Framework
for Urban Nature formally requires planners to refer all
building proposals in green structure areas to the city
council. Citizens may legally challenge the council
decisions. On five occasions since 1998, the courts have
allowed the council to build on this land. According to
department officials, the potential value of this policy is
uncertain. It is interesting to
compare the Utrecht case with Breda, a city where green
structure planning has played an important role since the
early 1980s. The Breda story illustrates a strategic
planning approach that started with the GSP and succeeded in
giving a prominent role to green areas in an integrated
approach to planning urban projects (Verburg et al.,1994;
Tjallingii, 1995: 125). In the Utrecht situation both the
Leidsche Rijn development and the Singel project confirm the
potential value of the GSP as a tool for integration. This
shows that a GSP, as proposed in the first hypothesis, can
act as a tool for strengthening the role of green areas in
urban planning. However, it seems as if the tool performs
best if it is not used in a narrow, defensive way, but in a
more open process to facilitate cooperation and integration
between green and red. ecological networks,
traffic and water The Utrecht case
confirms the hypothesis that the GSP tool has the potential
to bring nature back into the heart of the city. The Utrecht
planners felt the need to develop additional tools to
achieve this goal: a Policy Framework for Urban Nature and
an implementation programme with an annual budget. The
Utrecht case also illustrates that green structure planning
and the planning of pedestrian and bicycle routes are
natural allies. The 1990 GSP explicitly refers to this
combination, but apparently the plan did not play a
prominent role in the realisation of concrete greenway
projects. Although the hypothesis on joint strategies for
green structure and water planning is not supported by the
experience of the past decade, it seems that the Utrecht
planners were just late in discovering the potential of
combined green and water strategies. Other Dutch cities, for
example Breda and Drachten (Tjallingii, 1996: 114, 256), had
taken the lead, but after the successful Leidsche Rijn
planning experience Utrecht joined the pioneers in this
field. From a wider
perspective, nature and ecology are ambiguous concepts in
planning terms. On the one hand there is a concrete but
narrow object-oriented approach aimed at species and nature
reserves. On the other hand, there is a broad
process-oriented approach to ecology and planning. The
Strategy of the Two Networks (Tjallingii, 2000:104) uses
ecological processes related to water and traffic in a tool
for integrated urban planning. One implication is that green
and red are no longer considered to be enemies because both
are seen as part of the urban ecosystem. The dialogue between
object-oriented and process-oriented ecology in urban
planning is an international issue. In his study of
Scottsdale, Arizona, for example, Cook (2000) positions
himself as an object-oriented planner of ecological networks
for certain species. Turner (1998:137) looks at greenways in
a broad ecological way that is akin to the process approach
of Michael Hough (1984, 1995). Experiences in Dutch cities
suggest that a broad process approach creates good general
ecological conditions for urban life that may be further
developed for use in concrete species-oriented plans.
Starting with plans for individual species, however, does
not necessarily lead to good general conditions for urban
planning. strategies and
budgets The Utrecht experience
only partially supports the hypothesis that a GSP sets the
priorities for the survival of green areas when budgets come
under pressure. Although the municipal council adopted the
final document, the GSP was a product of one department and
so it did not reflect a broad consensus on priorities.
Moreover, the weak connection with financial planning has
been a major flaw of the GSP, especially in the first few
years. There are other options
for combining green structure planning and financial
planning, as demonstrated by the principle of give and take
in the Breda GSP (Verburg et al. 1994: 270). This implied
that in neighbourhoods with a lot of green areas some public
green could be turned into private green or even into red.
The GSP included the agreement that the Parks Department
itself could use the money generated in this way to improve
the quality of green areas in other places. This gave the
Parks Department the means to invest in the main green
network, even in a period of severe budgetary
constraint. In Utrecht, the link
between green structure planning and financial planning
became much stronger after the 1998 Policy Framework for
Urban Nature. The updated green structure map guided
negotiations between the local, provincial and national
governments on investment in green areas. The relationship between
spatial plans and investment is an emerging theme.
Traditionally, spatial planners have only had communicative
and regulative tools at their disposal to provide a
framework for investment by other parties. Hajer &
Zonneveld (2000: 339) argue for a rethinking of the
detached, coordinative role of spatial planners. The Utrecht
case study illustrates that what is discussed at the
national planning level is already being put into practice
at the local level. But at both levels the relevant question
is about the choice between sectoral projects or integrated
projects. In both new and existing urban districts it may be
obvious for local authorities to initiate projects that
integrate red and green, but Dutch municipalities do not
have many financial resources of their own. In this
situation, support from national sectoral ministries is
vital for local integrated projects. structure planning and
projects The hypothesis here is
that the GSP will improve the conditions for a coherent
package of projects. The Utrecht case study shows that the
1990 GSP can indeed be seen as a step towards a coherent
view of the connections between green areas. It took a
second round of green structure planning to establish a
clear link between this perspective and a programme for
project implementation. However, the Policy Framework for
Urban Nature that resulted from this second round became
more sectoral, with a narrow ecological orientation. It
gained strength but lost the wider perspective. Again, the comparison
with the Breda case is illuminating. In the Breda case,
green structure planning became an instrument for the
emancipation of the green sector and gradually led to the
creation of a fruitful climate of cooperation. A broad team
of committed politicians and officials from different
departments realised a wide range of integrated projects for
sustainable urban development. These projects combine water
and traffic issues with new habitats for wildlife and other
aspects. In 2002, for the third time in three years, Breda
won the sustainable city award, a competition between 300
Dutch municipalities. This demonstrates the city's
structural commitment to the issues that were put on the
agenda by the Green Structure Plan and other strategic
documents almost twenty years ago. enemies or
allies The discussion about
green structure planning, illustrated by the Utrecht case,
demonstrates the limited impact of defensive approaches.
Offensive strategies that combine spatial planning with
investment strategies may be more fruitful. However, the
best approach to the problems and challenges of urban areas
is not a defensive or offensive strategy for limited issues,
but an integrated approach. There is much to be gained by
making creative use of the opportunities that present
themselves if green structure planning joins forces with
planning for nature, greenways and water in the city. In
doing so, green structure planners can focus on contributing
to the quality of the built environment, rather than
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Working
Group 1A -
Comparison of Case Studies Other papers
relating to people/ ecology interface Sheffield to
do
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