SUMMARY OF RECOMMENDATIONS FOR POLICYMAKERS ON ADAPTION TO CLIMATE CHANGE IN WATER ENGINEERING

Abstract

SUMMARY OF RECOMMENDATIONS FOR POLICYMAKERS ON ADAPTION TO CLIMATE CHANGE IN WATER
ENGINEERING

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NUMBER 3 / 2015
THE SPHERIC COMMUNITY SEE PAGE 73
MODELLING WATER WAVES
WITH GPUSPH
SEE PAGE 85
SPECIFICATIONS FOR PHYSICAL
AND NUMERICAL STUDIES SEE PAGE 90
hydrolink
SPH
[SMOOTHED PARTICLE HYDRODYNAMICS]
IN HYDRAULICS

93
hydrolink number 3/2015
IAHR
management of urban water systems. Various
impact assessment procedures and adaptation
measures should be developed and tested in
order to find the most cost-effective method for
management and control of the urban water
environment. Examples of some existing
adaptation measures are:
•Storage and infiltration devices together with
re-naturalization of urban watercourses are
more and more frequently considered and
their use should be further enhanced.
However, more research is necessary to
optimize their application particularly if condi-
tions are changing (drainage flow regime,
sediment inputs, vegetation growth linked
with temperature, etc.)
SUMMARY OF RECOMMENDATIONS
FOR POLICYMAKERS ON ADAPTION
TO CLIMATE CHANGE IN WATER
ENGINEERING
This report is a contribution of the IAHR Working Group on Climate Change to the scientific and
technical debate on this global challenge in the water sector. Some experts in different fields, from
our Association, reviewed and recommended structural and non-structural adaptation measures
being taken or to be taken in the hydro-environment engineering community to mitigate the impact
of climate change on humans, nature and infrastructures.
IAHR WORKING GROUP ON CLIMATE CHANGE
Trend analyses and changes
detection in space-time data
Public bodies dealing with the policy and
management of water resource systems, should
investigate adaptation measures to face the
following issues related to observed trends:
•Understand and quantify short- and long-
term trends in hydroclimatic variables
especially precipitation and streamflow and
other essential climatic variables
•Evaluate the occurrences, variability and
sudden changes of extremes (considering
frequency and magnitude) in space and time
and develop sustainable and climate-change
sensitive hydrologic designs
•Assess the influences of climate variability on
streamflow and precipitation changes at
different spatial and temporal scales consid-
ering the extent of regional climatology influ-
ences
•Understand changes in trends and attribute
or separate them based on natural
variability or anthropogenic influences
Rainfall and Runoff
Climate change is expected to cause a shift to
more intense individual storms and fewer weak
storms as temperatures increase. Return
periods are projected to be reduced by about
10-20% per degree Celsius (°C) over most of
the mid-latitude land masses, with larger
reduction over wet tropical regions. It is recom-
mended that design flood estimation and
planning for an asset or activity should
consider: service life or planning horizon, design
standard, purpose and nature of the asset or
activity, screening analysis, climate change
projections and their consequences of impact,
and statutory requirement. It is also recom-
mended to take into consideration also a class
of worst case extreme events estimated to
occur under climate change as survival critical
or edge of survivability, partly because
projected future changes in design value may
have high uncertainty.
Downscaling and Adaptation to
Urban Hydrology Scale
The main challenge in urban hydrology is to
predict accurately the future variability of urban
hydrologic processes (such as temperature,
rainfall, and runoff) at the scale of the urban
area in the context of climate change in order to
build suitable scenarios for the operation and
The competition between food, water and soil in drought-prone areas will become more severe in a
warmer climate (photo: R. Ranzi in Southern Vietnam)

drought. Droughts are expected to have their
patterns of occurrence and magnitude changed
in the future. Policy leadership is required to
support efforts toward identifying and funding
adaptation measures and related research
such as:
4Groundwater quantity and quality data
collection
4Conjunctive use of surface and ground
water resources
4Managed aquifer recharge
4Water reuse and brackish groundwater
supplies
4Rainwater harvesting
4Protection of groundwater supplies
4Improved tools for management, planning,
and decision making
4Water demand management
4Adaptation of policy, legal and institutional
frameworks for water management
Impact on Hydropower Generation
and Mountain Hydrology
The impact of projected rainfall and evapotran-
spiration losses changes at the global scale
imply highly variable spatial patterns of runoff
changes and resulting hydropower generation
potential. More clear is the projected impact on
mountain hydrology, with a projected shift of the
snowmelt season to early spring months, a
decrease of summer runoff and an increased
variability of runoff regimes, thus enhancing the
potential impact of droughts and floods on
inflow to reservoirs. Public bodies dealing with
the policy and management of water resource
and energy should investigate and implement
adaptation measures to face the following
topics:
•increasing variation (distribution and quantity)
on water incoming to hydropower reservoirs
imply the need of an increase of storage
volumes, in some cases.
•Adaptation measures at individual scale
(mainly storage or infiltration) should also be
favoured but they are only efficient up to
some given rainfall volume or intensity; so
they should be included in the overall
management plan at the municipality scale,
which requires complementary tools to
integrate water, social and economic issues
Adaptation in Groundwater
Management and Drought
Management
Groundwater will be increasingly critical in
sustaining water supplies through periods of
climate change as it will help balance the larger
fluctuations in precipitation and increased water
demands caused by high temperature and
Roberto Ranzi, and Guinevere Nalder
contributed to homogenize and assembly this
document.
The individual sections have been
prepared by the following
members of the group
Premlal L. Patel, SVNIT Surat, India
Ramesh Teegavarapu, Florida Atlantic
University, USA. Trend analyses and changes
detection in space-time data
James Ball, Sydney University of Technology,
Australia.
Prof. Eiichi Nakakita, Disaster Prevention
Research Institute, Kyoto University, Japan.
Rainfall and Runoff
André Paquier, IRSTEA, France
Van-Thanh-Van Nguyen, Mc Gill University,
Canada. Downscaling and Adaptation to
Urban Hydrology Scale
Sang-Il Lee, Dongguk University, Republic of
Korea
Carlos Galvão, Campina Grande University,
Brazil. Groundwater and Drought
Management
Gregory Shahane De Costa, UNITEC, New
Zealand. Impact on the Coastal environment
and adaptation in coastal engineering
Abdalla-Abdelsalam Ahmed, UNESCO Chair
in WR, Khartoum, Sudan
Elpida Kolokytha,- Aristotle University of
Thessaloniki, Greece. Trans-Boundary
Watershed Management
Yangwen Jia, Institute of Water Resources &
Hydropower Research, China
Young-Oh Kim, Seoul National University,
Republic of Korea. Decision Making for
Climate Change Adaptations and Water
Resources Management
Structural measures as reservoirs and irrigation channels can mitigate the effects of the projected
enhanced variability of runoff. But also non-structural measures as improved tools for management,
planning, and decision making in reservoirs operation can be effective for adapting to a changed water
cycle
94 hydrolink number 3/2015

IAHR
•Increasing damages to the connectivity of
water bodies and injures to the river
ecosystems imply reservoir regulation paying
more attention to environmental issues as an
adaptation measure.
•Increasing demand and competition among
different water uses imply more accurate
planning and management optimization of
the water resources and participation of
stakeholders in decision making processes.
Climate Change, Sea Level Rise and
its Impact on Land and Water
Sea level rise may also be ascerbated by storm
surges and wave set up. In addition to causing
loss of coastal land, these sea level variations
will directly impact the surrounding ground
water table. While construction of embank-
ments, dikes, and dams etc., could be imple-
mented in suitable areas to prevent land loss,
the preferable approach would be to demarcate
areas under threat and use them for recreational
purposes, with very minor construction.
Trans-Boundary Watershed
Management
The management of trans-boundary water-
sheds requires an integrated regional approach
which should consider:
•the increase in future water variability.
•Changing social, economic and climate
conditions which may alter current hydro-
political balances, in terms of potential
inability of states to meet their treaty commit-
ments.
•Water scarcity as effect of climate change will
have impact on international conflict and
security.
•An effective international legal framework
addressing future challenges of climate
change is required.
Decision Making for Climate Change
Adaptations and Water Resources
Management
The decision making process under a changing
climate should be based on principles that can
handle effectively primary attributes of climate
change such as deep uncertainty and non-
stationarity. Good decisions under climate
change can:
•perform reasonably well over the entire range
of uncertainty,
•allow various options through the entire
decision making process,
•be iteratively refined as new information
including trial errors is available,
•take into consideration a class of worst case
extreme events estimated to occur under
climate change as survival critical or edge of
survivability.
Key aspects to be considered in the decision
making process include:
4Climate change impact on water resources
management
4Technical adaptations to Climate Change
4Institutional adaptations to Climate Change
4Legislation adaptation to Climate Change
4Capacity building improvement
4Public involvement improvement
About the IAHR Book Series
This Book Series includes Design Manuals
and Monographs. The Design Manuals
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series editor Peter A. Davies
;ƉƵď͘ŶůΛƚĂLJůŽƌĂŶĚĨƌĂŶĐŝƐ͘ĐŽŵͿ͘
New in the Series IAHR Monographs
Hydraulicians in the USA 1800-2000
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Willi H. Hager
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