Introduction
The United Nations Sustainable Development
Goals [3] (SDG) aim to provide a framework for
the challenges that need collaborative and joint
focus from governments, the private sector, civil
society, and people. These challenges include
some important global environmental factors.
One of the challenges mentioned is to take
urgent action to combat climate change and its
impacts, partly because of emissions of carbon
dioxide (CO 2 ) and other greenhouse gases
resulting from the use of fossil fuels [4]. Climate
change is related to urban water management
since a changing climate impacts weather, with
the intensity of rain events, rising sea levels, i.e.,
in many areas and others, perhaps the opposite
effects occur. The challenge is not only urban as
water management affects land-use management.
The problem of managing the impacts of severe
amounts of water is, therefore, becoming more
complex. There is a need to be able to assess
systems of systems across a catchment.
This entry introduces the main concepts used
in modelling urban surface water runoff and, as an
example, presents a model of the Amager district
of Copenhagen, Denmark. It is intended as an
introduction for those interested in urban drainage
modelling. The approach used in the example
presented for inspiration aims to illustrate the
opportunities in urban drainage modelling and is,
in principle, independent of location.
There are several inherent difficulties in managing the overall challenge of a severe rain event.
Water engineers and hydrologists have developed
advanced modelling tools for analysis given the
increased complexity of observed phenomena.
Development of Challenges in Urban
Surface Water
The effects of the changing weather on the environment, infrastructure, and people vary with the
weather and climate ranging from droughts to
elevated water levels in rivers and rising sea levels
from increased freshwater runoff. In many places
around the world, the change in weather results in
more and more significant rain events as well as
more severe rain events [5], while others suffer
from more intense and more prolonged droughts.
In urban areas such as in Denmark, which
follows European Union Water Management
guidelines and directives, rainwater is led out of
the city through sewer systems into local rivers or
streams, often passing through a wastewater treatment plant. In Europe, though there was significant post-World War II modernization, there
remain substantial portions of the sewer system
in urban areas established in the eighteenth and
nineteenth century [6]. The networks have since
expanded and many of them renovated to accommodate urban growth. The primary purpose of the
sewer system has been and is today to store and
transport wastewater as well as runoff from
rainwater.
Designing a sewer system to be able to handle
the water which runs off and does not percolate
into the ground during rain is a challenge by itself.
Engineers have been managing the problem by
developing methodologies for dimensioning and
designing sewer systems to drain the surface during rain and ensure that they understand and build
into codes the effects of not only subsurface systems but also surface (asphalt) and supra surface
(roof) drainage systems.
An example of how engineering societies take
responsibility for the development of the design
approach is the Engineering Society in Denmark
[7]. They have since 1949 published general
guidelines and advice to the engineering community [7] as do many other authorities or experts in
other jurisdictions around the world [8]. When it
is found relevant, they update or publish new
guidelines – generally based on advances in
research or observational evidence demonstrating
the need for design updates.
When rain events become more (or much less)
severe, the capacity and the design of the sewer
systems do not match the future needs as the flow
conditions of the systems change. In the case of
more intense water flow, the direct approach may
be to aim for expanding the network to accommodate higher capacity. However, expanding networks by increasing the size is expensive and
thus often not an option. Therefore, both the
230
Urban Drainage Modelling for Management of Urban Surface Water
The United Nations Sustainable Development
Goals [3] (SDG) aim to provide a framework for
the challenges that need collaborative and joint
focus from governments, the private sector, civil
society, and people. These challenges include
some important global environmental factors.
One of the challenges mentioned is to take
urgent action to combat climate change and its
impacts, partly because of emissions of carbon
dioxide (CO 2 ) and other greenhouse gases
resulting from the use of fossil fuels [4]. Climate
change is related to urban water management
since a changing climate impacts weather, with
the intensity of rain events, rising sea levels, i.e.,
in many areas and others, perhaps the opposite
effects occur. The challenge is not only urban as
water management affects land-use management.
The problem of managing the impacts of severe
amounts of water is, therefore, becoming more
complex. There is a need to be able to assess
systems of systems across a catchment.
This entry introduces the main concepts used
in modelling urban surface water runoff and, as an
example, presents a model of the Amager district
of Copenhagen, Denmark. It is intended as an
introduction for those interested in urban drainage
modelling. The approach used in the example
presented for inspiration aims to illustrate the
opportunities in urban drainage modelling and is,
in principle, independent of location.
There are several inherent difficulties in managing the overall challenge of a severe rain event.
Water engineers and hydrologists have developed
advanced modelling tools for analysis given the
increased complexity of observed phenomena.
Development of Challenges in Urban
Surface Water
The effects of the changing weather on the environment, infrastructure, and people vary with the
weather and climate ranging from droughts to
elevated water levels in rivers and rising sea levels
from increased freshwater runoff. In many places
around the world, the change in weather results in
more and more significant rain events as well as
more severe rain events [5], while others suffer
from more intense and more prolonged droughts.
In urban areas such as in Denmark, which
follows European Union Water Management
guidelines and directives, rainwater is led out of
the city through sewer systems into local rivers or
streams, often passing through a wastewater treatment plant. In Europe, though there was significant post-World War II modernization, there
remain substantial portions of the sewer system
in urban areas established in the eighteenth and
nineteenth century [6]. The networks have since
expanded and many of them renovated to accommodate urban growth. The primary purpose of the
sewer system has been and is today to store and
transport wastewater as well as runoff from
rainwater.
Designing a sewer system to be able to handle
the water which runs off and does not percolate
into the ground during rain is a challenge by itself.
Engineers have been managing the problem by
developing methodologies for dimensioning and
designing sewer systems to drain the surface during rain and ensure that they understand and build
into codes the effects of not only subsurface systems but also surface (asphalt) and supra surface
(roof) drainage systems.
An example of how engineering societies take
responsibility for the development of the design
approach is the Engineering Society in Denmark
[7]. They have since 1949 published general
guidelines and advice to the engineering community [7] as do many other authorities or experts in
other jurisdictions around the world [8]. When it
is found relevant, they update or publish new
guidelines – generally based on advances in
research or observational evidence demonstrating
the need for design updates.
When rain events become more (or much less)
severe, the capacity and the design of the sewer
systems do not match the future needs as the flow
conditions of the systems change. In the case of
more intense water flow, the direct approach may
be to aim for expanding the network to accommodate higher capacity. However, expanding networks by increasing the size is expensive and
thus often not an option. Therefore, both the
230
Urban Drainage Modelling for Management of Urban Surface Water