This document summarizes a study assessing the risks of climate change on urban development and drainage. It outlines the objectives to evaluate the impact of climate change on urban rainfall extremes and revise drainage design criteria. The methodology uses climate models and downscaling to estimate impacts and urban rainfall-runoff simulation to obtain runoff data. A literature review covers topics like drainage infrastructure design, sewer systems, urban resilience, and impacts of climate change. The conclusions state that evaluating climate change impacts increases drainage reliability and development needs to consider adaptation, mitigation and resilience.

1. INDIAN INSTITUTE OF TECHNOLOGY ROORKEE
Abhishek Chintawar, M.Tech, IIT Roorkee - 247 667 (UK) India
ASSESSING THE RISKS OF CLIMATE CHANGE IN URBAN
DEVELOPMENT AND DRAINAGE
DEPARTMENT OF WATER RESOURCES AND
DEVELOPMENT

2. 2
CONTENTS –
 Introduction
 Objectives
 Methodology
 Literature Review
 Conclusion
 References

3. 3
INTRODUCTION – What is Climate Change
UNFCCC IPCC
Change of climate that is attributed directly
or indirectly to human activity that alters the
composition of the global atmosphere and
that is in addition to natural climate
variability observed over comparable time
periods.
Change in the state of the climate that can
be identified by changes in the mean and/or
the variability of its properties, and that
persists for an extended period, typically
decades or longer.

4. 4
Causes of Climate Change -
 Natural Causes –
• Volcanic Activity
• Solar Output
• Earth’s orbit around the sun
 Anthropogenic Causes –
• GHG’s
• Degradation of Forests

5. 5
Effects of Climate Change –

6. 6
OBJECTIVES -
 Assessment on the urban rainfall extremes and urban
drainage. ( Majorly due to the anthropogenic factors )
 Revisions in the design criteria by considering the impact of
climate change.
 Improvement of the urban drainage system performance.
 Adopting practices to ensure adaptation, mitigation,
resilience and the responses.

7. 7
METHODOLOGY – CLIMATE CHANGE IMPACT
ESTIMATIONS ARE BASED ON SIMULATIONS WITH CLIMATE MODELS
Theory -
 Conducting CC studies on
urban drainage is highly
complicated, mainly because
of low resolution of data,
which cannot be applied to
local regions.
 There is a gap in between the
local drainage scales and the
model scales.
Figure -

8. 8
METHODOLOGY -
Models -
 General Circulation
Models GCM’s a d
Regional Circulation
Models RCM’s .
 Downscaling of results
fro GCM’s/RCM’s are
needed because these
models are not able to
describe the rainfall at
high resolution required
for drainage studies.
Figure -

9. 9
METHODOLOGY -
MODELS -
 GCM’s Spatial Resolutio is
100 by 100 km whereas of
RCM’s is y k a d 5
by 50 km.
 RCM’s a use i itial a d
boundary conditions from the
output of GCM’s, si e RCM
accounts for finer scale.
DOWNSCALING -
 Downscaling is the process of
moving from large scale
predictor to the local
predictand, and through this
process a relationship
between the predictor and
predictand is obtained.

10. 10
METHODOLOGY -
 After the downscaling is done the obtained results are then
verified. Climate models provide an assessment of
anthropogenic impacts only.
 After that we use Urban Rainfall-Runoff Simulation to obtain
the runoff data for the urban catchments. This data is then
further used for all design purposes.
 Suitability should be checked before adoption the modelling
and downscaling technique since projected impacts are
uncertain due to uncertainty in climate projections and also
due to uncertainties in models, since models are often
calibrated and validated against past data which may have
only few extremes.

11. 11
LITERATURE REVIEW -
SR.
NO.
AUTHORS TOPIC OBJECTIVES CONCLUSIONS
1. Mailhot,A.,
et al.,(2009)
Design of urban
drainage
infrastructure
Revision Modifies the IDF curves. 3
parameters – climate
projections, level of
performance, expected lifetime.
2. Semadeni-
Davies, A., et
al.,(2008)
Sewer system Impact of CC Increase sewer infiltration,
Reduced capacity of system due
to overflow.
3. Leichenko,
R.,(2011)
Urban resilience Need of urban
cities to become
resilient
Ecological, disaster risk,
economics, governance.
4. Willems, P.,
et al.(2013)
Urban drainage
design rules -
Belgium
Revision Change in IDF, Systems currently
designed for 20yr return period
might flood with a mean
recurrence interval of 5yr by
end of the century.

12. 12
LITERATURE REVIEW -
SR.
NO.
AUTHOR TOPIC OBJECTIVES CONCLUSIONS
5. Willem,P., et
al.(2012)
Impact
assessment
Methods and
shortcomings
Statistical downscaling better than
dynamic downscaling, 25yr time
series are too short for trend
detection for single precipitation
series.
6. Ashley, R. M.,
et al.(2005)
Flooding Predicting risks
and responses
Current sewer modelling techniques
replicate the performance of below
ground pipe systems, but do not
accurately predict surface flows that
occur after the onset of flooding.
7. Hamin, E. M.,
et al.(2009)
Urban form
and CC
Balancing
adaptation and
mitigation
Mitigation-To reduce global warming
over long term(dense), Adaptation-
Protect from sudden dangers(open).

13. 13
LITERATURE REVIEW -
SR.
NO.
AUTHOR TOPIC OBJECTIVES CONCLUSION
8. Arnbjerg-
Nielsen, K., et
al.(2013)
Impacts of CC Rainfall
extremes due
to
anthropogenic
induced CC
Majority of GCM simulations are
based on low CC scenario,
leading to calculated global
surface temp. increase of 2-3°C.
Combination of natural and man
made causes is difficult to
assess.
9. Karamouz, M,
et al.(2010)
Improvement of
drainage
performance
Selection of
BMP’s
Algorithm is developed selecting
the BMP’s to i prove syste
performance and reliability in
dealing with floods.

14. 14
CONCLUSIONS -
 Evaluating CC and its impact on urban flooding increases
the reliability of urban drainage.
 Urban development should be done keeping in mind
parameters like mitigation, adaptation, resilience, etc.

15. 15
REFERENCES -
[1] Arnbjerg-Nielsen, K., Willems, P., Olsson, J., Beecham, S.,
Pathirana, A., Gregersen, I. B., & Nguyen, V. T. V. (2013).
Impacts of climate change on rainfall extremes and urban
drainage systems: a review. Water Science and
Technology, 68(1), 16-28.
[2] Ashley, R. M., Balmforth, D. J., Saul, A. J., & Blanskby, J. D.
(2005). Flooding in the future–predicting climate change, risks
and responses in urban areas. Water Science and
Technology, 52(5), 265-273.
[3] Hamin, E. M., & Gurran, N. (2009). Urban form and climate
change: Balancing adaptation and mitigation in the US and
Australia. Habitat international, 33(3), 238-245.

16. 16
REFERENCES -
[4] Karamouz, M., Hosseinpour, A., & Nazif, S. (2010).
Improvement of urban drainage system performance under
climate change impact: Case study. Journal of Hydrologic
Engineering, 16(5), 395-412.
[5] Leichenko, R. (2011). Climate change and urban
resilience. Current opinion in environmental sustainability, 3(3),
164-168.
[6] Mailhot, A., & Duchesne, S. (2009). Design criteria of urban
drainage infrastructures under climate change. Journal of
Water Resources Planning and Management, 136(2), 201-208.
[7] Semadeni-Davies, A., Hernebring, C., Svensson, G., &
Gustafsson, L. G. (2008). The impacts of climate change and
urbanisation on drainage in Helsingborg, Sweden: Combined
sewer system. Journal of Hydrology, 350(1), 100-113.

17. 17
REFERENCES -
[8] Vörösmarty, C. J., Green, P., Salisbury, J., & Lammers, R. B.
(2000). Global water resources: vulnerability from climate
change and population growth. science, 289(5477), 284-288.
[9] Willems, P., Arnbjerg-Nielsen, K., Olsson, J., & Nguyen, V. T.
V. (2012). Climate change impact assessment on urban rainfall
extremes and urban drainage: methods and
shortcomings. Atmospheric research, 103, 106-118.
[10] Willems, P. (2013). Revision of urban drainage design
rules after assessment of climate change impacts on
precipitation extremes at Uccle, Belgium. Journal of
Hydrology, 496, 166-177.