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Vision 2030
The resilience of water supply and
sanitation in the face of climate change
Technology fact sheets
Authors:
Dr Katrina Charles, Robens Centre for Public and Environmental Health, University of Surrey
Dr Kathy Pond, Robens Centre for Public and Environmental Health, University of Surrey
Dr Steve Pedley, Robens Centre for Public and Environmental Health, University of Surrey
Contributors:
The authors would like to thank the following individuals who participated in a working session to
define climate risks and technology vulnerabilities and adaptations:
Mr Chee-Keong Chew, Water, Sanitation, Hygiene and Health, World Health Organization
Dr Barbara Evans, Water and Environment, University of Leeds
Professor Barry Lloyd, Centre for Environmental Health Engineering, University of Surrey
Mr Brian Reed, Water, Engineering and Development Centre, Loughborough University
Ms Beth Scott, Policy and Research Division, Department for International Development
Professor Mike Smith, Water, Engineering and Development Centre, Loughborough University
Dr David Sutherland, Principal Consultant, Atkins
Dr Richard Taylor, Department of Geography, University College London
Disclaimer
The fact sheets were prepared in good faith. The named authors alone are responsible for the views
expressed in this publication. Neither the World Health Organization and University of Surrey, UK,
nor their employees, contractors or subcontractors, make any warranty, express or implied, or
assume any legal liability or responsibility for its accuracy, completeness, or any party’s use of its
contents.
The fact sheets are not edited by the World Health Organization to conform to the full requirements
of WHO style. The published material is being distributed without warranty of any kind, either
expressed or implied. The responsibility for the interpretation and use of the material lies with the
reader. In no event shall the World Health Organization be liable for damages arising from its use.
Introduction
The Technology projection study (included in this CD-ROM) discusses a number of themes related
to climate change, and in particular describes the consequential changes in rainfall patterns, and the
observed and perceived impact of these changes on drinking-water supply and sanitation facilities.
The evidence gathered from the literature, and from the opinions and experiences of experts
working in the field, demonstrates the vulnerability of drinking-water supply and sanitation
facilities, at all levels of sophistication, to the vagaries of the present climate. These observations
suggest that without intervention, the vulnerability of these facilities to climate-induced damage
will increase in the future as climate conditions become more extreme. This assumption is
supported by the opinions of many of those working in the water and sanitation sector.
The evidence gathered in preparing that report also showed that there are interventions that can be
made to reduce the vulnerability of drinking-water supply and sanitation facilities to climate
change. Several examples of successful adaptation were noted. Based on the positive results of
those interventions and the opinions of water and sanitation professionals, we have compiled a
series of fact sheets containing guidance about the kind of interventions that may be considered
suitable for increasing the resilience of drinking-water supply and sanitation facilities to the
consequences of several climate-change scenarios. These notes should not be considered a complete
authoritative guide to the interventions that can be made to protect these facilities from climate
change. The impacts of changing patterns of rainfall are many and varied, and will be conditional
on the local environment. Similar scenarios, therefore, will have different consequences depending
on where they occur. These guidance notes provide a first attempt at presenting a framework for
adaptation in the water supply and sanitation sector and, as such, they are intended to raise
awareness of the potential problems that will be faced in the short to medium term in the water and
sanitation sector. Their contents are not fixed but will change and grow over time as new
knowledge and experience are added to them. Most of all, however, the guidance notes are intended
to promote debate in the water and sanitation sector.
The intended users of these guidance notes are water supply and sanitation professionals, water
resource managers, public health professionals, communities managing their own water supplies,
and nongovernmental organizations working in the water supply and sanitation sector.
Four climate scenarios are addressed in these vulnerability and adaptation guidance notes:
• increase in precipitation, with increase in rainfall intensity;
• increase in precipitation, with no increase in rainfall intensity;
• decrease in precipitation, with increase in rainfall intensity;
• decrease in precipitation, with no increase in rainfall intensity.
The fact sheets are divided up by key issues for water supply and sanitation facilities as a result of
these four climate scenarios. The relevant key issues for each scenario are indicated in Table 1.
The adaptations have been divided into four categories:
• capital expenditure, which includes long-term adaptations that will not necessarily be
suitable for immediate implementation;
• operational expenditure, which includes adaptations that can be made to existing systems;
• monitoring, which includes programmes that can be implemented immediately to support
planning decisions, or implemented in the long term to support continuing decisions;
• Socioeconomic tools such as community education, training and public awareness that can
support short-term and long-term adaptations.
Table 1
Summary of problems relating to climate change for four different scenarios
Scenario Key issues
Increase in
precipitation,
increase in
rainfall
intensity
Increase in
precipitation,
no increase in
rainfall
intensity
Decrease in
precipitation,
increase in
rainfall
intensity
Decrease in
precipitation,
no increase in
rainfall
intensity
Increased risk of flooding � � �
Increase in groundwater
recharge, with a rise in groundwater level, increases in
interflow and more saturated
soils
� �
More extreme rainfall events � �
Increased run-off with more
erosion
� �
Water availability decreases
including less surface flow, drop
in surface water levels, and
decreased groundwater levels
� �
In all cases we refer the reader to the Water Safety Plan approach as a means of consistently
ensuring the safety of a drinking-water supply. Model water safety plans for the water facilities
referred to below are provided in
http://www.who.int/water_sanitation_health/dwq/wsp170805AppB.pdf.
The water supply and sanitation facilities discussed in these fact sheets are those defined as
“improved” by the WHO/UNICEF Joint Monitoring Programme on Water Supply and Sanitation
(see Table 2). Levels of coverage are discussed in Chapter 4 of the Technology projection study,
based on data from the WHO/UNICEF Joint Monitoring Programme.
The fact sheets provide guidance with regard to vulnerability and adaptation of water supply and
sanitation facilities to the effects of climate change. They deal with the following key themes:
Water supply
− Flooding increases
− Groundwater recharge increases
− Increase in extreme rainfall events
− Run-off increases
− Water availability decreases
Sanitation
− Flooding increases; increase in extreme rainfall events
− Groundwater tables rising
− Water availability decreases.
Table 2
Definitions of improved water supply and sanitation facilities
Water supply or sanitation
facility
Notes or definition
Utility-managed piped water
supplies
May have either a surface water or groundwater source, and include
infrastructure such as a reservoir and a treatment plant, with treated
water delivered to users via a piped network.
Community-managed drinking-
water systems
These may be with piped or non-piped distribution. The definition of a
community drinking-water system will vary. It may be based on
population size or the type of supply; or based on the approaches to
administration and management. Drinking-water systems in periurban
areas in developing countries – the communities surrounding major
towns and cities – may also have the characteristics of community
systems.
Public standpipes Standpipes deliver water supplied by a utility or community managed
supply, and hence have the same vulnerabilities as one of those systems.
However, with public standpipes, the water is not delivered to the
consumers, but to a tap or standpipe for which there is public access.
Protected wells Includes boreholes and dug wells.
Protected springs A protected spring is one in which the eye of the spring (where the water emerges from the ground) has a protective wall or box around it.
The area behind the box is backfilled with stones to filter the
groundwater.
Rainwater collection Collection of rainwater from roofs: rainwater is collected in guttering
placed around the eaves of the building.
Sewers Sewer systems collect all household wastewater, as well as industrial
and commercial wastewater, and transport it via a network of sewerage pipes to a central treatment or disposal site. Combined sewer systems
are included in the definition of sewers.
Septic tanks Septic tanks collect all household wastewater, and should collect only
wastewater, not storm water.
Improved pit latrines Includes pour-flush latrine, and simple (or double) pit or ventilated
improved pit latrine, allowing for acceptable local technologies.
Composting or dry latrines Composting or dry latrines are constructed with the collection chamber
for faeces (and urine) above ground. The position of the collection
chamber facilitates drying of the contents and easy access for its
removal.
Key issue: Flooding increases Utility-managed piped water supplies
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
Increased flooding
reduces the availability
of safe water resources.
Flooding events increase
the level of chemical and
microbiological
contamination in water
sources, increasing the
risk to public health.
Increased suspended
sediment load carried by flood waters exceeds the
treatment capacity of
water treatment facilities.
Develop, implement and
update water safety plans.
Design flood storage areas
on rivers to mitigate the
impacts of floods. This may
include implementing land
management activities to
increase infiltration of water and reduce severity of
floods, e.g. terracing,
adequate urban drainage, reforestation, retention
basins.
Adopt higher design
standards for infrastructure
to take higher and more
frequent floods into
consideration, particularly in
terms of return periods for significant events.
Best management practices (grass swales, permeable
surfaces, balancing ponds).
Seasonal forecasting.
Flood forecasting.
Hydrological monitoring
stations.
Rain gauging.
Earth observation data.
Enhanced inspection of
infrastructure.
Raise awareness among
the public of the risk of
contamination during
floods and the reduction
in drinking-water
availability.
Dissemination of public
health advisory notices with advice about dealing
with the issues.
Possible mechanisms
include posting leaflets,
door-to-door visits, and
radio and television
announcements.
Fluctuating surface
water levels may cause
problems for
infrastructure
Water intakes may be
left exposed as water
levels fall.
Develop, implement and
update water safety plans.
Design water intake to
Switch to groundwater
sources when available.
Repair damage as
Hydrological monitoring
stations. Rain gauging.
Earth observation data.
Raise awareness among
operational managers of
the need for enhanced
inspection procedures.
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
Highly turbulent water
flows in rivers after
heavy rain may damage
intakes.
accommodate varying water
levels (for example floating
booms). River intakes
strengthened to withstand
more turbulent flows.
Develop groundwater
sources where feasible.
necessary.
Plan for emergency water
supplies.
Enhanced inspection of
infrastructure
Communicate the
justification for enhanced
inspection as a result of
climate change.
Floods may overtop
reservoir causing
structural damage
Catastrophic failure of
dams, leading to reduced
storage capacity and
potentially damaging
releases of water.
Design overflows for source
reservoirs to prevent failure
Maintain spillways and
channels in good order.
Early warning system
installed.
Disseminate early
warnings.
Update and disseminate
evacuation procedures.
Increase frequency with
which emergency
procedures are practised.
Flooding of treatment system
Floods may lead to structural damage of the
treatment works, or to
the failure of pumping stations. Water supplies
fail.
Develop, implement and update water safety plans.
Site water treatment works and other major
infrastructure away from
flood zones, or build
appropriate flood defences.
Protect electrical
installations.
Smaller more localized treatment systems may help
to spread risk of widespread
water shortages.
Plan after-flooding response to assess and
address infrastructure
damage.
Take treatment unit offline
and apply corrective action.
Planned emergency
response. Increase
chlorination. Plan for
emergency supplies.
Intensify monitoring of water quality after event
and before going back
on line.
Manage communication of early warning of event
to the public.
Develop communication
procedures for notifying
the public when the water
is safe. Possible
mechanisms include
posting leaflets, door-to-
door visits, and radio and
television
announcements.
Raise awareness among
water engineers of risks
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
from water quality
changes during flooding
and how water treatment
can be adapted to manage
the risks.
Groundwater quality
deterioration during floods
Floodwaters contaminate
shallow and deep groundwater sources
through damaged or
disused boreholes.
Shallow groundwater
may also be affected by
infiltration of flood
water through soil
layers.
Develop, implement and
update water safety plans.
Improve source protection.
Introduce chlorination where
not previously applied.
Relocate groundwater
source.
Impose well head
protection areas and well head inspection
procedures.
Increase chlorination of the
water after flood.
Intensify water quality
monitoring after flood.
Raise awareness among
water engineers of risks from water quality
changes during flooding
and how water treatment
can be adapted to manage
the risks.
Manage communication
of early warning of event
to the public.
Develop communication
procedures for when
water is safe. Possible mechanisms include
posting leaflets, door-to-
door visits, and radio and
television
announcements.
Surface water quality
deterioration during
floods.
Floodwater carries
increased sediment load
that may exceed the
treatment capacity of the
water treatment works.
Run-off water from
upstream may carry
Develop, implement and
update water safety plans.
Adapt water treatment for
flood conditions depending on water source and
contamination.
Select appropriate water
treatment stages to suit
water quality.
Dig out buried intakes after flood waters recede.
Design and implement a
monitoring programme
of flooding in water
sources.
Monitor silt build-up in
reservoirs.
Raise awareness among
water engineers of risks
from water quality
changes during flooding
and how water treatment can be adapted to manage
the risks.
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
higher concentrations of
chemical and microbial
contaminants.
Introduce additional, more
robust barriers and treatment
stages.
Relocate abstraction points.
Monitor raw water
quality.
Manage communication
of early warning of event
to the public.
Develop communication
procedures for when water is safe. Possible
mechanisms include
posting leaflets, door-to-door visits, and radio and
television
announcements.
Entry of contaminated
flood water into water
supply pipes.
Localized or widespread
contamination of the
water distribution
system.
Develop, implement and
update water safety plans.
Where possible, aim to site
pipes in area of low risk of flooding.
In areas where flooding is likely, aim to keep water and
sewage pipes separate in
case of cross contamination
through fractures.
Relocate water pipes away
from open sewers and
drainage channels.
Implement pipe
maintenance programme to
reduce leakage and the
potential for ingress.
Implement pipe
maintenance programme to
reduce leaks from sewers, particularly where located
close to water pipes and
where cross connection is
possible. Include cut-off
walls in high-risk areas.
Implement rehabilitation
programmes to improve
hydrostatic pressure.
Flush out flooded pipe
network after waters have receded to remove
sediments. Shock
Design and implement a
monitoring programme
for flooding of the pipe
network. This might
include monitoring of water pressure in pipes,
water quality
monitoring, or a reporting mechanism for
when areas above pipes
are flooded.
Review risks and need
for refurbishment or
replacement.
Raise awareness amongst
the public of
contamination issues
during floods and
reduction in drinking-water availability. This
may be done by posting
leaflets, door-to-door visits; radio and TV
announcements to inform
people to boil water.
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
chlorinate the system and
introduce increased
chlorination until risk of
contamination has been
reduced.
Entry of contaminated
water at service reservoir.
Localized or widespread
contamination of the water distribution
system.
Develop, implement and
update water safety plans.
Re-line reservoirs.
Re-point concrete reservoirs.
Replace or repair damaged
access points to the service
reservoir.
Clear drainage channels.
Take tanks offline for
repairs.
Flush tank and distribution
before re-commissioning.
Repair leaks, drains and
valve box. Repair valve if
showing signs of wear
Validation by water
quality monitoring at times of major works.
Regular inspection.
Periodic integrity testing.
Tracer tests.
Raise awareness among
the public of contamination issues
during floods and
reduction in drinking-
water availability. This
may be done by posting
leaflets, door-to-door
visits, and radio and
television announcements
to inform people to boil
water.
Contamination of drinking-water in supply
affecting large
populations.
Major public health risk. Develop, implement and update water safety plans.
Decentralize and diversify water systems to mitigate
the number of people
affected.
Develop back-up sources,
such as linkages to other
sources or emergency tank
supplies, to mitigate risk.
Zoning of water supplies for monitoring and
management of distribution
system.
Implement leak detection
and repair procedures.
Intensification of water quality monitoring above
minimum level specified
in WHO guidelines.
Raise awareness among the public of
contamination issues
during floods and reduction in drinking-
water availability. This
may be done by posting
leaflets, door-to-door
visits, and radio and
television
announcements.
Establish communication procedures with the
relevant public health
departments.
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
May also require the
issue of warnings to boil
water.
Enhance and practice emergency response
procedures.
Flooding causes damage
to bridges that support
trunk mains or
distribution pipes over
rivers.
Localized or widespread
disruption to water
supplies.
Develop, implement and
update water safety plans.
Review relative risks and the
cost-benefits of laying the
trunk main under the river or
supporting from bridge over
the river. Select most cost-
beneficial option.
Install multiple crossings for
distribution pipes.
Install isolation valves at
both sides of crossing.
Carry out regular
inspection and
vulnerability assessment
of structures.
Develop monitoring,
management and
communication
procedures with the
bridge owners, if
different from water
supply provider.
Community-managed piped water supplies
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
Increased flooding
reduces the availability
of safe water resources.
Flooding events increase
the level of chemical and
microbiological
contamination in water
sources, increasing the risk to public health.
Develop, implement and
update water safety plans.
Adopt higher design
standards for infrastructure to take
Seasonal forecasting.
Flood forecasting.
Establish centralized support unit to provide
Hydrological monitoring
stations.
Enhanced inspection of infrastructure.
Raise awareness among
the community of the
risk of contamination
during floods and
reduction in drinking-water availability.
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
Increased suspended
sediment loads carried
by flood waters may
exceed the treatment
capacity of any small-scale water treatment
system that has been
added to the supply.
higher and more frequent
floods into consideration,
particularly in terms of
return periods for
significant events.
Where possible,
implement land
management activities to increase infiltration of
water and reduce severity
of floods, e.g. terracing,
reforestation.
technical and
administrative assistance
in the event of flooding
Dissemination of public
health messages with
advice about dealing
with the issues,
including household treatment and boil water
notices where
appropriate. This may be done by posting leaflets,
door-to-door visits, radio
and television
announcements, and by
posting notices in
prominent places in the
community.
Fluctuating surface water levels may cause
problems for
infrastructure.
Water intakes may be left exposed as water
levels fall.
Highly turbulent water
flows in rivers after
heavy rain may damage
intakes.
Develop, implement and update water safety plans.
Strengthen river intakes to withstand more turbulent
flows.
Develop groundwater
sources where feasible.
Establish centralized support unit to provide
technical and
administrative assistance in the event of flooding.
Switch to alternative
sources when available.
Repair damage as
necessary.
Plan for emergency water supplies.
Hydrological monitoring stations.
Enhanced inspection of infrastructure
Raise awareness among community members of
the need for enhanced
inspection procedures.
Communicate the
justification for
enhanced inspection as a
result of climate change.
Floods may overtop
reservoir causing
structural damage.
Catastrophic failure of
the dam, leading to
reduced storage capacity
Design overflows for
source reservoirs to
prevent failure.
Maintain spillways and
channels in good order.
Evaluate need for early
warning system.
Disseminate early
warnings.
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
and potentially
damaging releases of
water.
Evaluate the need for
evacuation procedures.
Increase frequency with
which emergency
procedures are practised if appropriate.
Flooding of water
treatment system.
Distribution of
contaminated water
through the distribution
system.
Water supplies fail.
Structural damage to the
treatment system.
Develop, implement and
update water safety plans.
Site the water treatment
works and other major
infrastructure away from
flood zones, or build
appropriate flood
defences.
Protect electrical
installations, e.g. with
walled treatment plant or sandbag defences.
Establish centralized
support unit to provide
technical and
administrative assistance
in the event of flooding.
Plan after-flooding
response to assess and
address infrastructure
damage. Take treatment unit
offline and apply
corrective action.
Planned emergency
response. Increase
chlorination. Plan for
emergency supplies.
Sanitary inspection.
Increase monitoring of
water quality after event
and before going back
on line, possibly using
external support systems.
Manage communication
of early warning of
event.
Develop communication
procedures for when
water is safe.
Raise awareness of risks
from water quality changes during flooding
Raise awareness about risks from infrastructure
damage after flooding
and how to assess and
address them.
Raise awareness of the
need for household water
treatment.
Groundwater quality
deterioration during floods.
Floodwaters contaminate
shallow and deep groundwater sources
through damaged or
disused boreholes.
Develop, implement and
update water safety plans.
Improve source
protection.
Impose well head
protection areas and well head inspection.
Sanitary inspection.
Intensify water quality
monitoring after flood.
Develop communication
procedures for when water is safe.
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
Shallow groundwater
may also be affected by
infiltration of floodwater
through soil layers.
Risk to public health from consuming the
water.
Relocate groundwater
source where possible.
Shock chlorination after
flood.
Raise awareness about
risks from water quality
changes during flooding
and the need for
household water
treatment. Possible mechanisms include
posting leaflets, door-to-
door visits, radio and television
announcements, and
positing notices in
prominent places in the
community
Surface water quality
deterioration during
floods.
Floodwater carries
increase sediment load
that may exceed the treatment capacity of any
small-scale water
treatment system that is part of the supply
system.
Run off water from
upstream may carry
higher concentrations of
chemical and microbial
contaminants.
Risk to public health
from consuming the
water.
Develop, implement and
update water safety plans.
Adapt water treatment for
flood conditions
depending on water source and contamination.
Introduce additional more
robust barriers and
treatment stages.
Relocate abstraction
points, where possible.
Select appropriate water
treatment stages to suit
water quality.
Dig out buried intakes
after the flood waters recede.
Sanitary inspection.
Simple monitoring of raw water quality, e.g.
turbidity.
Develop communication
procedures for when
water is safe.
Raise awareness about
risks from water quality changes during flooding
and the need for
household water
treatment. Possible
mechanisms include
posting leaflets, door-to-
door visits, radio and
television
announcements, and posting notices in
prominent places in the
community.
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
Issue boil water notices
where appropriate.
Entry of contaminated
flood water into water
supply pipes.
Widespread
contamination of the
water supply system.
Risk to public health from consuming the
water.
Develop, implement and
update water safety plans.
Aim to site pipes in area
of low risk of flooding.
Relocate water pipes away
from open sewers and
drainage channels.
Introduce a pipe
maintenance programme
to reduce leakage and
potential for ingress,
possibly with the aid of a central support system.
Rehabilitation to
improve hydrostatic
pressure.
Flush out flooded pipe
network after waters
have receded to remove
sediments.
Shock chlorination.
Sanitary inspection.
Develop and implement
reporting mechanism
when areas above pipes are flooded.
Review risks and need
for refurbishment or
replacement.
Raise awareness about
risks from water quality
changes during flooding
and the need for
household water treatment. This may be
done by posting leaflets,
door-to-door visits, radio
and television
announcements, and
posting notices in
prominent places in the
community.
Issue boil water notices where appropriate.
Develop communication procedures for when
water is safe
Contamination of
drinking-water in supply
affecting whole
community.
Severe risk to public
health from consuming
the water.
Develop, implement and
update water safety plans.
Develop back-up sources,
such as linkages to other
water sources or
community water supply
systems.
Develop emergency back-
up supplies.
Regular programme of
leak detection and repair.
Sanitary inspection. Raise awareness about
risks from water quality
changes during flooding
and the need for
household water
treatment
Issue boil water notices where appropriate.
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
Develop communication
procedures for when
water is safe
This may be done by
posting leaflets, door-to-door visits, radio and
television
announcements, and posting notices in
prominent places in the
community.
Enhance and practise
emergency response
procedures.
Flooding causes damage to bridges that support
mains or distribution
pipes over rivers.
Localized or widespread disruption to water
supplies.
Develop, implement and update water safety plans.
Review risks and benefits of burying main under
river or supporting from
bridge over the river.
Select least risk option.
Install isolation valves at
both sides of crossing.
Carry out regular inspection and
vulnerability assessment
of structures.
Develop monitoring, management and
communication
procedures with the bridge owners, if not
owned by the
community.
Public standpipes
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
See also utility- and community-managed piped water supplies
Standpipes inundated
with contaminated
floodwater.
Standpipes become
inaccessible or are
damaged by the floodwater.
Quality of the water at the standpipe
deteriorates and there is
potential for more
widespread
contamination of the
distribution system.
Develop, implement and
update water safety
plans.
Place on elevated
platform to allow access during floods.
Construct standpipes
from durable materials to
reduce damage during
floods.
Review the risks and
benefits of removing the standpipe if it is located
in an area at high risk of
flooding.
Adopt a standpipe
maintenance programme
to reduce potential for ingress (e.g. chambers
are sealed).
Develop response plan
after flooding to assess
damage to standpipes
and to inform future
improvement.
Flush out pipes and
clean standpipes after
floods.
Sanitary inspection of
standpipe.
Increase water quality
monitoring after floods
have receded.
Raise awareness about
risks from water quality
changes during flooding and the need for
household water
treatment.
Issue boil water notices
where appropriate.
Develop communication
procedures for when
water is safe.
This may be done by posting leaflets, door-to-
door visits, radio and
television
announcements, and
posting notices in
prominent places in the
community.
Protected wells (boreholes and dug wells)
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
Increased contamination
of groundwater and lateral flow in soil.
Floodwaters introduce
contamination into the groundwater by
Site well away from
latrines and other sources of groundwater
Repair rendering of well
wall when necessary.
Sanitary inspection.
Monitor the response of
Prevent latrines being
constructed nearby.
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
infiltration though the
soil, by damaged or
disused bore holes or
dug wells. Lateral flow
increases, transporting
contaminants below the surface.
Significant public health risks from consuming
the water.
pollution. groundwater levels and
quality to flooding, to
identify vulnerability.
Raise awareness about
risks from water quality
changes during flooding
and the need for
household water
treatment.
Issue boil water notices
where appropriate.
Develop communication
procedures for when
water is safe.
This may be done by
adding warning labels to
contaminated wells and
boreholes and removing the notices when the
water is safe.
In areas where there is a
high density of boreholes
and dug wells, consider
developing an
association of well
owners and stakeholders
to manage and monitor wells and provide
guidance to users.
Raise awareness of well
use in emergency
situations.
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
Well is inundated.
Widespread
contamination of the
aquifer, causing long-
term problems with the
quality of water in the
well.
Significant public health
risks from consuming the water.
Build bunds (banks,
dykes or levees) to divert
flow, or raise the well
head.
Site on embankments.
For deep wells, ensure
the casing extends below the level of shallow
aquifers.
Extend lining above
ground.
Convert dug wells to
hand pumped tubewells
with sanitary completion.
Improve well lining to
prevent ingress of water
from soil and shallow
groundwater, where
appropriate.
Implement land
management activities to reduce severity of
floods, e.g. terracing,
adequate drainage, reforestation, retention
basins.
Repair and clear ditches.
Increase size of ditch.
Repair plinth.
Shock chlorinate well
water after the floods
have subsided.
Provision of alternative
water sources during
inundation or household
treatment.
Sanitary inspection.
Increase water quality
monitoring.
Monitor conductivity if in coastal or estuarine
areas.
Raise awareness about
risks from water quality
changes during and after
flooding, and the need
for household water
treatment.
Issue boil water notices
where appropriate.
Develop communication
procedures for when
water is safe.
This may be done by
adding warning labels to
contaminated wells and
boreholes and removing the notices when the
water is safe.
In areas where there is a
high density of boreholes
and dug wells, consider
developing an
association of well
owners and stakeholders
to manage and monitor wells and provide
guidance to users.
Raise awareness of well
use in emergency
situations.
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
Prepare flood risk map
and update as necessary.
Protected springs
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
Entry of contaminated
surface water at the
spring.
Erosion around the
spring box, damaging
protection.
Quality of water from
the spring deteriorates.
Water quality changes
may be rapid but short-
term if contamination
enters at the spring.
Significant public health risks from consuming
the water.
Ensure spring water
collection and storage
infrastructure are
properly designed,
protected and maintained
to prevent entry of
contaminated water, and
are constructed from durable materials.
Build bunds (banks, dykes or levees) and cut-
off drains to divert flow
away from collection
area.
Regularly check the
infrastructure and repair
if necessary.
Maintain surface water
diversion ditch above
and around spring.
Sanitary inspection.
Raise awareness among
users about risks from
water quality changes
during and after flooding
and the need for
household water
treatment.
Advise community to
avoid using
contaminated springs for drinking during and after
floods, until quality has
been verified.
Issue boil water notices
where appropriate.
Develop communication
procedures for when water is safe.
Groundwater quality deteriorates.
Quality of the water from the spring
deteriorates. Water
Investigate alternative sources if appropriate
and possible.
Properly seal abandoned wells to protect
groundwater quality.
Water quality monitoring after a flood
to verify that water
Advise community to avoid using
contaminated springs for
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
quality changes may be
long-term if the aquifer
becomes contaminated.
Maintain well head or
spring head protection
areas.
quality is not
compromised.
drinking during and after
floods, until quality has
been verified.
Raise awareness among
users about possible contamination of the
aquifer following floods,
irrespective of localised flooding at the collection
area.
Flooding reducing
availability of safe
water.
Eye of the spring
submerged under
floodwater.
No access to water
source.
Develop springs outside
flood prone areas, where
possible.
Implement land
management activities to reduce severity of
floods, e.g. terracing,
adequate drainage, reforestation, retention
basins.
Prepare flood risk map
and update as necessary.
Investigate alternative
sources.
Raise awareness among
users of potential
consequences of
flooding on the quality
of water and actions to
be taken in such circumstances.
Rainwater collection
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
Collection or storage
facilities are inundated.
Rainwater collection or
storage systems become
inaccessible.
Introduction of contamination into the
rainwater storage
system.
Avoid using
underground storage
facilities in flood prone
areas, and ensure proper
design and maintenance of all storage and
collection facilities to
prevent contamination.
Raise level of storage
tanks where possible.
Consider accessibility
issues when designing rainwater collection for
an area to ensure that
some supplies are accessible in floods.
Consider increasing capacity.
Investigate alternative
sources.
Clean and disinfect all
storage and collection
facilities, after
inundation in flood
water, before use.
Strengthen collection
and storage facilities.
Plan for collection of
increased silt load.
Sanitary inspection.
Monitor for microbial
contamination where
possible.
Raise awareness among
the users about possible
contamination of the
system following floods,
including contamination of the stored water.
Provide information
about increased silt load
and increased capacity.
Key issue: Groundwater recharge increases Utility-managed piped water supplies
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
Potential deterioration in
the quality of
groundwater sources as a
result of more rapid
transport of water in
subsurface, and potential
compromising of
sanitation systems.
Rising groundwater
levels flood sanitation
systems, creating
pathways for the
potentially rapid
dispersal of
contaminants into
groundwater.
Rising water level
mobilize microbial and
chemical contaminants.
Ingress of groundwater
into treated water
supply, potentially
contaminating water.
Significant public health
risk from consuming the
water.
Develop, implement and
update water safety
plans.
Investigate increasing
protection zones around
wells, to reduce
contamination sources.
Adapt water treatment to
respond to changing
water quality.
Increase the depth of
well intakes, where
possible.
Move towards
continuous positive
pressure in system.
Investigate the benefits
of placing increased
reliance on groundwater systems in areas of rising
groundwater, provided
appropriate treatment
can be added.
Maintain positive
pressure in pipes
wherever possible
Pipe maintenance
programme to fix leaks
in pipes.
Design and implement a
monitoring programme
for groundwater sources
based on groundwater
level.
Monitor the response of
groundwater levels and
quality to increasing rainfall, to identify
vulnerability.
Monitor water quality in
at-risk pipe networks
Raise awareness among
resource managers,
water and sanitation
professionals, public
health professionals and
consumers about
possible groundwater
contamination issues and
health impacts.
Raise awareness among
consumers of the need for household water
treatment.
Issue boil water notices
when appropriate.
Increase vulnerability of
flooding (see flooding).
Community-managed piped water supplies
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
Potential deterioration in
the quality of
groundwater sources as a
result of more rapid
transport of water in subsurface, and potential
compromising of
sanitation systems.
Rising groundwater
levels flood sanitation
systems, creating
pathways for the
potentially rapid dispersal of
contaminants into
groundwater.
Rising water level
mobilizes microbial and
chemical contaminants.
Ingress of groundwater into treated water
supply, potentially
contaminating water.
Significant public health
risk from consuming the water.
Investigate increasing
protection zones around
wells, to reduce
contamination sources.
Adapt water treatment to
respond to changing
water quality.
Develop, implement and
update water safety
plans.
Investigate the benefits of placing increased
reliance on groundwater
systems in areas of rising groundwater, provided
appropriate treatment
can be added.
Increase the depth of
well intakes, where
possible.
Move towards
continuous positive
pressure in system.
Establish centralized
support unit to provide
technical and
administrative
assistance.
Maintain positive
pressure in pipes
wherever possible.
Pipe maintenance
programme to fix leaks
in pipes.
Design and implement a
monitoring programme
for groundwater sources
based on groundwater
level.
Monitor the response of
groundwater levels and
quality to increasing
rainfall, to identify
vulnerability.
Sanitary inspection.
Raise awareness among
the community of the
risk of contamination
from rising.
Dissemination of public
health messages with
advice about dealing
with the issues,
including the need for
household treatment and
boil water notices where
appropriate.
This may be done by
posting leaflets, door-to-
door visits, radio and television
announcements, and by
posting notices in prominent places in the
community.
Increase vulnerability of
flooding (see flooding).
Public standpipes
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
See utility- and community- managed piped water supplies
Protected wells (boreholes and dug wells)
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
Potential deterioration in the quality of
groundwater sources as a
result of more rapid transport of water in
subsurface, and potential
compromising of
sanitation systems.
Significant risk to the health of consumers.
Increase in groundwater level could also lead to a
reduction in the
vulnerability of
protected wells and
provide a more
sustainable water supply
than alternative water
supply options.
Investigate increasing protection zones around
wells, to reduce
contamination sources.
Adapt water treatment to
respond to changing
water quality.
Set intakes at greater
depth or modify
pumping regimes, where
feasible.
In the event of a
decrease in the
vulnerability of
protected wells, an
increase in the reliance
on groundwater sources
should be considered.
Establish centralized support unit to provide
technical and
administrative assistance.
Act upon sanitary risk
inspections.
Design and implement a monitoring programme
for groundwater sources
based on groundwater level.
Monitor the response of
groundwater levels and
quality to increasing
rainfall, to identify
vulnerability
Sanitary inspection.
Prevent latrines being constructed nearby.
Raise awareness among users of the wells about
risks from water quality
changes during flooding
and the need for
household water
treatment.
Issue boil water notices
where appropriate.
Develop communication
procedures for when
water is safe.
This may be done by
adding warning labels to
contaminated wells and
boreholes and removing
the notices when the water is safe.
In areas where there is a high density of boreholes
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
and dug wells, consider
developing an
association of well
owners and stakeholders
to manage and monitor
wells and provide guidance to users.
Raise awareness of well use in emergency
situations.
Protected springs
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
Increased flow of the
spring may cause
damage to the existing
infrastructure.
Spring protection
damage, leading to
increase vulnerability of
the spring to ingress of surface contamination.
Significant risk to the health of users of the
spring.
Investigate installing
additional drainage or
overflow pipes to
alleviate pressure build-up.
Design and construct spring box storage to
account for increase
flows.
Repair structure and
reinforce as necessary to
reduce risks identified by
sanitary inspection.
Establish centralized
support unit to provide technical and
administrative
assistance.
Sanitary inspection. Communicate risk to the
users of the spring.
Advise household
treatment as necessary.
Potential deterioration in
the quality of
groundwater sources as a
result of more rapid
transport of water in
subsurface, and potential
compromising of sanitation systems.
Significant risk to the
health of users of the
spring.
Investigate increasing
protection zones around
source, to reduce
contamination sources.
Adapt water treatment to
respond to changing water quality.
Act upon sanitary risk
inspections.
Establish centralized
support unit to provide
technical and
administrative assistance.
Design and implement a
monitoring programme
for groundwater sources
based on groundwater
level.
Monitor the response of spring discharges to
Raise awareness among
users of the springs
about risks from water
quality changes and the
need for household water
treatment.
This may be done by adding warning labels to
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
groundwater levels and
quality to increasing
rainfall, to identify
vulnerability.
Sanitary inspection.
contaminated springs
and removing the notices
when the water is safe.
Key issue: Increase in extreme rainfall events
One of the main impacts of more extreme rainfall events will be flooding, so these tables build on the vulnerabilities of general flooding with
vulnerabilities associated with heavy rainfall and flash flooding.
Utility-managed piped water supplies
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
See also key issue: Flooding increases
Damage to
infrastructure.
Potential failure of the
drinking-water supply
system and loss of
service.
Public health risk from
contaminants entering
the water distribution system through damaged
pipes.
Design or adapt reservoir
overflows and spillways
to cope with larger
flows.
Adopt higher design
standards for
infrastructure to take more frequent extreme
weather events into
consideration.
Develop, implement and
update water safety
plans.
Response plan after
flooding to assess and
address infrastructure
damage.
Plan for emergency
supplies of drinking-
water to be available in the event of system
failure.
Hydrological monitoring
stations.
Rain gauging.
Earth observation data.
Enhanced inspection of infrastructure.
Raise awareness among
the public of the risk of
contamination during and
after extreme rainfall
events.
Raise awareness among
water engineers of risks from water quality changes
during extreme rainfall
events, and how to manage the risk.
Disseminate health
advisory notices to the
public with advice about
dealing with the risks.
Develop communication
procedures to notify public
when the water is safe.
Issue boil water notices if
appropriate.
Possible mechanisms
include posting leaflets,
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
door-to-door visits, and
radio and television
announcements.
Treatment and pumping
systems unable to work
if electricity is affected.
Potential failure of the
drinking-water supply
system and loss of
service.
Have reservoirs
throughout pipe network
to store treated water and
provide gravity fed water.
Develop, implement and
update water safety
plans.
Fill local reservoirs prior
to large storms to
provide gravity flow.
Hydrological monitoring
stations.
Rain gauging.
Earth observation data.
Enhanced inspection of
infrastructure.
Raise awareness among
the public of the risk of
contamination during and
after extreme rainfall events.
Raise awareness among
water engineers of risks
from water quality changes
during extreme rainfall
events, and how to manage
the risk.
Disseminate health advisory notices to the
public with advice about
dealing with the risks.
Develop communication
procedures to notify public
when the water is safe.
Issue boil water notices if
appropriate.
Possible mechanisms include posting leaflets,
door-to-door visits, and
radio and television announcements.
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
Increased erosion
leading to more polluted
run-off, with silt and
nutrients.
Increase in suspended
sediment loads may
exceed the treatment
capacity of the water
treatment facilities.
Public health risk from
contaminants entering
the water distribution system.
Land management –
minimize erosion with
planting schemes, buffer
strips and storm water
management.
Develop, implement and
update water safety
plans.
Maintain vegetation in
buffer strips next to
rivers.
Monitor water quality
and adapt treatment
processes to ensure that
water quality is not
compromised, such as by
increasing sedimentation time and improving
filtration systems.
Raise awareness among
the public of the risk of
contamination during and
after extreme rainfall
events.
Raise awareness among
water engineers of risks
from water quality changes during extreme rainfall
events, and how to manage
the risk.
Disseminate health
advisory notices to the
public with advice about
dealing with the risks.
Develop communication
procedures to notify public
when the water is safe.
Issue boil water notices if
appropriate.
Possible mechanisms
include posting leaflets,
door-to-door visits, and radio and TV
announcements.
Increased risk of
landslides on steep slopes causing damage
to infrastructure.
Potential failure of the
drinking-water supply system, and loss of
service.
Build treatment works
and pipe networks away from slopes that are at
risk of slippage.
Reinforce slopes where
there is a risk of slippage that may damage
infrastructure.
Hydrological monitoring
stations.
Rain gauging.
Raise public awareness on
risk of contamination during and after extreme
rainfall events.
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
Public health risk from
contaminants entering
the water distribution
system through damaged
pipes.
Reduced access to the
affected areas.
Develop, implement and
update water safety
plans.
Implement leakage
reduction plan, as
leakage can contribute to
landslides.
Enhanced inspection of
infrastructure.
Raise awareness among
water engineers of risks
from water quality changes
during extreme rainfall
events, and how to manage the risk.
Disseminate health advisory notices to the
public with advice about
dealing with the risks.
Develop communication
procedures to notify the
public when the water is
safe.
Issue boil water notices if
appropriate.
Possible mechanisms
include posting leaflets,
door-to-door visits, and
radio and television
announcements.
Groundwater quality,
particularly at shallow
depths, may deteriorate. Increased lateral flow in
soils may also spread
contamination.
Public health risk from
contaminants entering
the water distribution system.
Develop, implement and
update water safety
plans.
Consider constructing
deeper wells.
Ensure that wells are
sealed to several metres
below the water table.
Monitor water quality
and adapt treatment
processes to ensure that water quality is not
compromised.
Raise awareness among
water resource managers
and water engineers about the potential for lateral
transport of pathogens and
subsequent contamination of water.
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
Consider alternative
sources.
Disseminate health
advisory notices to the
public with advice about
dealing with the risks.
Develop communication procedures to notify the
public when the water is
safe.
Issue boil water notices if
appropriate.
Community-managed piped water supplies
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
See also key issue: Flooding increases
See also utility-managed piped water supplies
Increased risk of
landslides on steep slopes causing damage
to infrastructure.
Potential failure of the
drinking-water supply system, and loss of
service.
Public health risk from
contaminants entering
the water distribution system through damaged
pipes.
Reduced access to the
affected areas.
Where possible, avoid
installing pipes on slopes that are at risk of
slippage.
Develop, implement and
update water safety
plans.
Reinforce slopes where
there is a risk of slippage that may damage
infrastructure.
Establish centralized
support unit to provide
technical and administrative
assistance.
Raise awareness among
the community about the damage that landslides
can cause to
infrastructure and the potential effect on the
water supply system.
Public standpipes
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
See also key issue: Flooding increases
See also utility- and community-managed piped water supplies
Increased risk of
landslides on steep
slopes causing damage
to infrastructure.
Loss of water supply to
the standpipes.
Permanent loss of standpipe.
Site standpipes away
from slopes that are at
risk of slippage.
Reinforce slopes where
there is a risk of slippage
that may damage
infrastructure. If standpipes are located
on at-risk slopes, ensure
proper drainage.
Local professional
management (water
kiosks) rather than free
public standpipes will
create positive incentives
for management and protection of the
infrastructure.
Raise awareness among
the community about the
damage that landslides
can cause to infrastructure and the
potential effect on the
water supply system.
Protected wells (boreholes and dug wells)
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
See also key issue: Flooding increases
Increased risk of
landslides on steep
slopes causing damage
to infrastructure.
Permanent loss of
borehole or well as a
result of it being buried
under the landslide.
Damage to the structure of the borehole or well,
Build wells away from
slopes that are at risk of
slippage.
Reinforce slopes where
there is a risk of slippage
that may damage
infrastructure.
Monitor microbial
quality of water after the
well or borehole has
been renovated.
Raise awareness among
the community about the
damage that landslides
can cause to wells and
boreholes.
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
leading to a temporary
loss of supply.
Groundwater quality,
particularly at shallow
depths may deteriorate.
Increased lateral flow in
soils may also spread
contamination.
Significant public health
risk from consuming the
water.
Investigate increasing
protection zones around
wells, to reduce
contamination of
sources.
Site well away from
latrines and other
sources of groundwater
pollution.
Ensure that wells are
sealed to several metres
below the water table.
Sanitary inspection.
Monitor microbial
quality of water.
Raise awareness among
the community about the
potential for lateral
transport of pathogens,
and the potential for
contamination of water during and after extreme
rainfall events.
Raise awareness among
the community about the
benefits of household
water treatment.
Develop communication
procedures for notifying the community when the
water is safe.
Protected springs
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
See also key issue: Flooding increases
Increased risk of
landslides on steep slopes causing damage
to infrastructure.
Permanent loss of spring
as a result of it being buried under the
landslide.
Damage to the structure
of the spring, leading to
a temporary loss of supply.
Construct collection and
storage infrastructure, and fencing from durable
materials to reduce
damage during extreme
events. Ensure they are
properly designed and
maintained.
Reinforce spring
infrastructure and surrounds to prevent
slippage.
Sanitary inspection. Raise awareness among
the community about the risk of landslides and the
damage that they can
cause to springs.
Raise awareness among
the community about the benefits of household
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
Significant public health
risk from consuming the
water.
water treatment.
Develop communication
procedures for notifying
the community when the
water is safe
Groundwater quality, particularly at shallow
depths may deteriorate.
Increased lateral flow in
soils may also spread
contamination.
Quality of the water from the spring
deteriorates. Water
quality changes may be
long term if the aquifer
becomes contaminated.
Investigate alternative sources, if appropriate
and possible.
Properly seal abandoned wells to protect
groundwater quality.
Maintain well head or
spring head protection
areas.
Water quality monitoring after a flood
to verify that water
quality is not
compromised.
Advise the community to avoid using
contaminated springs for
drinking during and after
floods, until quality has
been verified.
Raise awareness among
users about possible
contamination of the
aquifer following floods, irrespective of localized
flooding at the collection
area.
Rainwater collection
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
See also key issue: Flooding increases
Increased risk of
landslides on steep
slopes causing damage
to infrastructure.
Permanent loss of
rainwater collection
system as a result of it
being buried under the landslide.
Ensure appropriate
design, construction and
maintenance, and use
durable materials. Ensure sufficient
overflow or bypass
Replace roof material
where appropriate.
Sanitary inspection.
Make regular checks to
ensure the infrastructure is not damaged.
Raise awareness among
the owners and users of
rainwater collection
systems about the damage that landslides
can cause to
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
Damage to the structure
of the collection system,
leading to a temporary
loss of supply.
facilities.
infrastructure.
Key issue: Run-off increases
Similarly to the impacts of more extreme rainfall events, one of the main impacts of increased run-off will be flooding, so these tables build on the
vulnerabilities of general flooding.
Utility-managed piped water supplies
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
See also key issue: Flooding increases
Erosion exposing and
damaging pipe work.
Potential failure of the
drinking-water supply
system and loss of
service.
Public health risk from
contaminants entering
the water distribution system through damaged
pipes.
Land management –
compaction of soils and
planting above pipes,
under paved roads etc.
Develop, implement and
update water safety
plans.
Implement leakage
reduction plan, as
leakage can contribute to
landslides.
Hydrological monitoring
stations.
Rain gauging.
Enhanced inspection of
infrastructure.
Raise awareness among
water engineers of risks
from water quality
changes from run-off
and how to manage the risk.
Disseminate health advisory notices to the
public with advice about
dealing with the risks.
Develop communication
procedures to notify the
public when the water is
safe.
Issue boil water notices
if appropriate.
Possible mechanisms
include posting leaflets,
door-to-door visits, and
radio and television
announcements.
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
Increased erosion
leading to more polluted
run-off, with silt and
nutrients.
Increased suspended
sediment loads may
exceed the treatment
capacity of the water
treatment facilities.
Public health risk from
contaminants entering
the water distribution system.
Land management –
minimize erosion with
planting schemes, buffer
strips and storm water
management.
Develop, implement and
update water safety
plans.
Maintain vegetation in
buffer strips next to
rivers.
Monitor water quality
and adapt treatment
processes to ensure that
water quality is not
compromised, such as by
increasing sedimentation time and improving
filtration systems.
Raise awareness among
water engineers of risks
from water quality
changes from run-off
and how to manage the
risk.
Disseminate health
advisory notices to the public with advice about
dealing with the risks.
Develop communication
procedures to notify the
public when the water is
safe.
Issue boil water notices if appropriate.
Possible mechanisms
include posting leaflets,
door-to-door visits, and
radio and television
announcements.
Community-managed piped water supplies (see also utility-managed piped water supplies)
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
See also key issue: Flooding increases
Increased erosion
leading to more polluted
run-off, with silt and nutrients.
Increased suspended
sediment loads may
exceed the treatment capacity of the water
treatment facilities.
Public health risk from
contaminants entering
the water distribution
system.
Land management –
minimize erosion with
planting schemes, buffer strips and storm water
management.
Develop, implement and
update water safety
plans.
Maintain vegetation in
buffer strips next to
rivers.
Establish centralized
support unit to provide technical and
administrative
assistance.
Monitor water quality
and adapt treatment
processes to ensure that water quality is not
compromised, such as by
increasing sedimentation time and improving
filtration systems.
Raise awareness among
the community of the
risk of contamination during and after extreme
rainfall events.
Disseminate health
advisory notices to the
public with advice about
dealing with the risks.
Develop communication
procedures to notify the
community when the
water is safe.
Issue boil water notices
if appropriate.
Possible mechanisms
include posting leaflets, door-to-door visits, and
radio and television
announcements.
Public standpipes (see also utility- and community-managed piped water supplies)
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
See also key issue: Flooding increases
Erosion damaging
standpipe.
Destruction of the
standpipe and loss of
service.
Public health risk from
contaminants entering the standpipe.
Land management –
minimize erosion with
planting schemes, buffer strips and storm water
management.
Use durable materials in
construction.
Maintain conditions
which mitigate erosion,
e.g. compaction of soils and plants in buffer
strips.
Establish centralized
support unit to provide
technical and
administrative
assistance.
Sanitary survey. Raise awareness among
the community about the
damage that erosion can cause to infrastructure,
and the potential effect
on the water supply system.
Disseminate health
advisory notices to the
public with advice about
dealing with the risks.
Develop communication
procedures to notify the community when the
water is safe.
Issue boil water notices
if appropriate.
Possible mechanisms
include posting leaflets,
door-to-door visits, and
radio and television
announcements.
Protected wells (boreholes and dug wells)
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
See also key issue: Flooding increases
Erosion Permanent loss of
borehole or well.
Damage to the structure
of the borehole or well,
leading to a temporary loss of supply.
Public health risk from
contaminants entering
the standpipe.
Ensure that well heads
are properly designed to
prevent erosion damage that may increase
infiltration.
Use compaction of soils
and planting around
infrastructure to increase
durability of structures.
Maintain conditions
which mitigate erosion
e.g. compaction of soils and plants in buffer
strips.
Monitor microbial
quality of water after the
well or borehole has been renovated.
Raise awareness among
the community about the
damage that erosion can cause to wells and
boreholes.
Develop communication
procedures to notify the
community when the
water is safe.
Protected springs
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
See also key issue: Flooding increases
Backfilled areas become
eroded leading to
contamination in
recharge area.
Damage to the structure
of the spring, leading to
a temporary loss of
supply.
Public health risk from
contaminants entering the spring.
Ensure that collection
infrastructure is properly
designed to prevent
erosion damage that might compromise the
integrity of the structure.
Ensure that fencing and
ditches are in good
repair; drain surface
water. Re-lay grass.
Sanitary survey.
Microbiological
monitoring of the spring water after rehabilitation.
Raise awareness of
possible water
contamination as a result
of erosion damage.
Rainwater collection
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
See also key issue: Flooding increases
Erosion around storage
area.
Damage to the structure
of the rainwater storage
tank, leading to a temporary loss of
supply.
Public health risk from
contaminants entering
the storage tank.
Ensure that area around
storage infrastructure is
designed to mitigate erosion; for example,
compaction of soils and
plants in buffer strips.
Maintain conditions
which mitigate erosion
e.g. compaction of soils and plants in buffer
strips.
Sanitary survey. Raise awareness among
users about the risks to
rainwater infrastructure from erosion.
Key issue: Water availability decreases Utility-managed piped water supplies
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
Insufficient water for
demand.
Water shortages and
potential for water
rationing.
Public health risk from
inappropriate water
saving in the home.
Low pressure in system may allow ingress of
contamination into the
water distribution network.
Intermittent water
supplies and pressure
changes in the
distribution network lead
to damage of the
infrastructure.
Develop, implement and
update water safety
plans.
Improve efficiency of
water use in non-
domestic water use.
Increase water storage capacity to provide
supply over extended dry
periods.
Investigate alterative
water sources and water
harvesting methods.
Investigate water reuse
schemes.
.
Develop emergency
water plan for times of extreme scarcity, such as
linkages to other sources
or emergency tank supplies.
Decentralization of
water systems may allow
for quicker adaptation to
local conditions.
Pipe maintenance
programme to reduce
leaks.
Prioritize allocation for
domestic use.
Monitor water pressure
in pipes to aid in
detection of leaks.
Monitor water use.
Water resource
monitoring.
Implement education
programme to reduce
water demand.
Raise awareness of reuse
of wastewater for
agricultural and
industrial purposes.
Implement discussions
with other water users
such as irrigators to manage the resource
cooperatively.
Promote the importance
of hygiene.
Review water pricing
policy as a method of
demand management.
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
Integration of systems
may protect from water
shortages. Conjunctive
water use.
More pronounced and
changing seasonality of
water supplies.
Increased levels of
contamination of the
source water, particularly at the end of
periods of drought.
Insufficient water to
meet demand.
Low pressure in system
may allow ingress of
contamination into the
water distribution network.
Intermittent water supplies and pressure
changes in the
distribution network lead
to damage of the
infrastructure.
Develop, implement and
update water safety
plans.
Increase water storage
capacity to provide
supply over extended dry
periods.
Increase infiltration to
groundwater when water
is available.
Investigate
supplementary water
sources.
Pipe maintenance
programme to reduce
leaks.
Prioritize allocation for
domestic use.
Water resource
monitoring.
Implement discussions
with other water users
such as irrigators to manage the resource
cooperatively.
Implement education
programme to reduce
water demand.
Raise awareness of reuse
of wastewater for
agricultural and industrial purposes.
Less water used for
critical domestic
purposes.
Public health risk from
inappropriate water
saving in the home.
Research low-water
usage appliances for
non-critical domestic
use.
Maintain a minimum
domestic supply.
Water use surveys. Promote the importance
of hygiene and raise
awareness among the
public about low water
use systems.
Decreased water flow
may result lower quality
Quality of the raw water
may deteriorate to the
Develop, implement and
update water safety
Seasonal forecasting. Water resource
monitoring.
Raise awareness among
water engineers of
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
source water; for
example, increase in
turbidity.
point where it exceeds
the treatment capacity of
the water treatment
facility.
Public health risk from consumption of the
water.
plans.
Redesign treatment plant
and improve filtration
systems.
Monitor water at inflow
and adjust treatment
accordingly.
possible contamination
issues resulting from
decreased water flow.
Decreased water flow
may lower levels in
reservoirs and damage
infrastructure or restrict
use.
Potential deterioration in
the quality of the stored
water.
Dams may be weakened
by prolonged low-
storage levels.
Investigate use of
underground storage.
Adapt intake
infrastructure to handle
low flows.
Adapt reservoirs to
handle low water levels.
Adjustable intakes to
draw from optimum
levels in the reservoir.
Water resource
monitoring.
Promote the importance
of hygiene and raise
awareness among the
public about low water
use systems.
Falling groundwater levels affect productivity
of supply wells.
Wells become unproductive, leading to
a loss of water supply.
Evaluate the vulnerability of wells to
seasonal and sustained
drought.
Manage groundwater
abstraction to maintain
drinking-water supply.
Investigate developing
deeper wells.
Promote rainwater harvesting to enhance
groundwater recharge.
Seasonal forecasting. Monitor the current relationship between
groundwater levels and
climate.
Implement discussions with other water users
such as irrigators to
manage the resource cooperatively.
Implement education
programme to reduce
water demand.
Raise awareness among
all stakeholders of reuse
of wastewater for agricultural and
industrial purposes.
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
Investigate the reuse of
wastewater for artificial
groundwater recharge.
Develop, implement and
update water safety plans.
Water becomes too
saline to use.
Loss of water supply. Develop, implement and
update water safety
plans.
Determine the cause and
degree of vulnerability.
Investigate treatment
systems that can treat
salinity.
Investigate alternative
water sources.
Promote rainwater
harvesting to enhance
groundwater recharge.
Investigate the reuse of
wastewater for artificial
groundwater recharge.
Investigate the potential
for conjunctive use of
water sources (blending
and dual multiple
sources).
Monitor salinity levels. Start discussions with
irrigators and other
aquifer users about the
risks to water quality
from different water
practices.
Reduced moisture in
soils may cause movement, damaging
infrastructure.
Movement and
infrastructure damage.
Ingress of contamination
into water system
Design for movement,
e.g. by using shorter lengths of pipes; or use
non-reticulated systems
on site.
Adapt maintenance
programme to identify breakages.
Monitor integrity of
pipes and reservoir structures.
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
through damaged pipes.
Public health risk from
consumption of the
water.
Leakage management
programme.
Community-managed piped water supplies (see also utility-managed piped water supplies)
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
Insufficient water for
demand, or increased
seasonality of water.
Water shortages and
potential for water
rationing.
Public health risk from
inappropriate water
saving in the home.
Low pressure in system
may allow ingress of contamination into the
water distribution
network.
Intermittent water
supplies and pressure
changes in the
distribution network lead
to damage of the
infrastructure.
Restrict water supplies
and switch pipes off.
Develop, implement and
update water safety
plans.
Improve efficiency of
water use in non-
domestic water use.
Increase water storage
capacity to provide supply over extended dry
periods
Investigate alternative
water sources and water
harvesting methods.
Investigate water reuse
schemes.
Pipe maintenance
programme to reduce
leaks.
Prioritize allocation for
domestic use.
Establish centralized
support unit to provide
technical and administrative
assistance.
Monitor for microbial
quality of water.
Educate communities
about reliable water
sources: how to select
them, what makes them
reliable, etc.
Raise awareness among
the community about
issues of quality and
infrastructure damage associated with
intermittent piped
supplies.
Promote the importance
of hygiene.
Implement education
programme to reduce
water demand.
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
Develop emergency
water plan for times of
extreme scarcity, such as
linkages to other sources
or emergency tank
supplies.
Integration of systems
may protect from water shortages.
Shared water use.
Decreased water flow
may result in increased
turbidity and decreased
dilution of pollution.
Quality of the raw water
may deteriorate to the
point where it exceeds
the treatment capacity of
the water treatment facility.
Public health risk from consumption of the
water.
Develop, implement and
update water safety
plans.
Redesign treatment plant and improve filtration
systems.
Establish centralized
support unit to provide
technical and
administrative
assistance.
Water resource
monitoring.
Monitor water at inflow
and adjust treatment accordingly.
Raise awareness among
the community of
possible contamination
issues resulting from
decreased water flow.
Disseminate health
advisory notices to the public with advice about
dealing with the risks.
Develop communication
procedures to notify
community when the
water is safe.
Issue boil water notices if appropriate.
Public standpipes (see utility- and community-managed piped water supplies)
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
The vulnerabilities, impacts and adaptations that are relevant to, and will affect the operation of public standpipes have been covered in the tables dealing with
utility- and community-managed piped water supplies.
Protected wells (boreholes and dug wells)
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
Insufficient water for
demand
Water shortages and
potential for water
rationing.
Public health risk from
inappropriate water
saving in the home.
Investigate alternative
and supplementary water
sources and water harvesting methods, such
as rainwater collection
and water reuse.
Prioritize water use for
drinking.
Investigate methods for
the artificial recharge of groundwater
Investigate catchment management practices to
promote infiltration.
Consider deepening the
wells and boreholes.
Ensure high levels of
maintenance on wells to
avoid unnecessary losses of water at the point of
use.
Monitor water use at
well for user pays
scheme, and assist in demand management.
Monitor the ability of
wells to cope with
current droughts
Implement education
programme to reduce
water demand.
Promote the importance
of hygiene.
Educate communities
about reliable water
sources: how to select
them, what makes them
reliable, etc.
Increased use of viable
wells causes increased
wear and tear, and
increased water demand.
Damage to well or
borehole increases the
risk of contamination
entering water source.
Determine the degree of
vulnerability through
investigating linkages
between climate and
Ensure high levels of
maintenance on in-
demand wells.
Sanitary survey.
Monitor the ability of
wells to cope with
Implement discussions
with other users of the
aquifer such as irrigators
and private well owners
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
Public health risk from
consumption of the
water.
groundwater, e.g.
residence times.
current droughts. to manage the resource
cooperatively.
Less water available for
hygiene and cleaning.
Public health risk from
inappropriate water
saving in the home.
Research cleaning and
hygiene methods that
have low-water usage.
Water use surveys. Raise awareness of the
importance of hygiene.
Groundwater levels
dropping, especially during a dry period or
season.
Water shortages and
potential for water rationing.
Public health risk from
inappropriate water
saving in the home.
Increased risk of
contamination of the
water at the end of the drought.
If supply from the well is
already variable, consider that the current
well may need to be
extended or new deeper
wells may need to be
installed.
Install relief wells that
can be uncapped for easy
use in dry periods to supplement existing
wells.
Determine the degree of
vulnerability.
Concentrate water
quality monitoring during periods of high
risk at the end of the
droughts.
Start discussions with
irrigators and other aquifer users about the
risks to water quality
from different water
practices
Water quality
deteriorates with increasing salinity.
Loss of water supply. Determine the cause and
degree of vulnerability.
Investigate treatment
systems that can treat
salinity.
Identify alternative, non-
saline sources.
Promote rainwater
harvesting to enhance
Monitor salinity levels. Start discussions with
irrigators and other aquifer users about the
risks to water quality
from different water
practices.
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
groundwater recharge.
Investigate potential for
re-use of treated
wastewater for artificial
groundwater recharge.
Protected springs
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
Insufficient water for
demand, including
seasonal shortages.
Water shortages and
potential for water
rationing.
Public health risk from
inappropriate water
saving in the home.
Investigate alterative and
supplementary water
sources and water
harvesting methods such
as rainwater collection
and water reuse.
Prioritize water use for
drinking.
Investigate methods for
the artificial recharge of
groundwater.
Investigate catchment
management practices to
promote infiltration.
Ensure high levels of
maintenance on springs
to avoid unnecessary
losses of water at the
point of use.
Monitor water use at
spring for user-pays
scheme, and assist in
demand management.
Monitor the ability of
springs to cope with
current droughts, and
map vulnerable springs.
Implement education
programme to reduce
water demand.
If appropriate, review
water pricing policy as a
method of demand
management.
Educate communities about reliable water
sources: how to select
them, what makes them reliable, etc.
Increased use of viable
springs increases water
demand.
Damage to the spring
increases the risk of
contamination entering
the water source. Public
health risk from
consumption of the water.
Determine the degree of
vulnerability through
investigating linkages
between climate and
groundwater, e.g.
residence times.
Ensure high levels of
maintenance for spring
infrastructure.
Monitor the ability of
spring to cope with
current droughts.
Implement discussions
with other users of the
aquifer such as irrigators
and private spring
owners to manage the
resource cooperatively.
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
Less water available for
hygiene and cleaning.
Public health risk from
inappropriate water
saving in the home.
Research cleaning and
hygiene methods that
have low-water usage.
Water use surveys. Raise awareness of the
importance of hygiene
and low water methods
available.
Springs become less
productive.
Loss of water supply.
Public health risk from inappropriate water
saving in the home.
Install storage facilities
to maximize collection.
Investigate other water
sources.
Determine the degree of
vulnerability through
investigating linkages
between climate and
groundwater, e.g.
residence times. Ensure
ability to cope with current droughts.
If the spring is known to be dependent on local
weather conditions,
consider that the spring
may have a limited
lifespan.
Ensure high levels of
maintenance for spring
infrastructure.
Monitor the ability of
spring to cope with
current droughts.
Implement a demand
management plan for
household water use and for other uses of the
spring and the aquifer.
Raise awareness of the
importance of hygiene
and low water methods
available.
Water quality
deteriorates with
increasing salinity.
Loss of water supply. Determine the degree of
vulnerability.
Identify alternative, non-
saline sources.
Investigate treatment
that treats salinity.
Monitor salinity levels in
groundwater.
Start discussions with
irrigators and other
aquifer users about the
risks to water quality
from different water practices.
Rainwater collection
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
Reduced rainfall or
changes in seasonality of
rainfall.
Reduced water
availability with the
potential loss of supply.
Increase size of
collection and storage
facilities to maximize
collection at other times.
Investigate alternative
and supplementary water
sources such as water
reuse.
Ensure that system is
maintained so that it is
functions well when it
rains.
Monitor water use to
assist in demand
management.
Implement education
programme with the
community of users to
reduce water demand.
Educate communities
about reliable water
sources: how to select
them, what makes them
reliable, etc.
Reduced water quality as
a result of build-up of
contaminants on
surfaces.
Public health risk from
consumption of the
water.
Divert “first-flush”
rainwater for uses other
than drinking.
Treat water before
drinking.
Sweep collector surfaces
during long dry spells.
Monitor microbial
quality of water where
possible.
Educate the users about
quality issues of “first-
flush” rainwater.
Key issues: Flooding increases; increase in extreme rainfall events; run-off increases
For sanitation facilities, there are many similarities between the impacts of extreme rainfall events, increased run-off and flooding, and hence these
three scenarios have been combined here in the guidance notes for increases in flooding.
Sewers
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
Infiltration of flood
water into sewer, leading
to plug flow of
pollutants and resuspension.
Overloading of treatment
works.
Pollution of water resources downstream.
Ingress of silt.
Use sustainable urban
drainage systems and
separate sewers.
Encourage decentralized
systems.
Clean sewers regularly.
Clean drains regularly
especially just before wet season.
Monitor silt levels,
blockages, cross-
connections and so on, in
drains and sewers.
Stop illegal connections
to foul sewers.
Inundation of sewerage
system including
treatment works.
Catastrophic failure of
the system.
Install flood defences,
catchment management.
Encourage decentralized
systems.
Invest in emergency
response equipment e.g.
mobile pumps kept in separate location.
Rehabilitation plan.
Rising receiving water
levels.
Overloading of sewers,
leading to backing-up.
Shallow sewers.
Flap valves.
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
High flows cause sewers
to flood into
environment and houses.
Decrease diameter of
pipes to attenuate and
store water.
Separate sewage and
stormwater systems.
Consider use of small
bore or other low-cost sewerage options at local
level to reduce costs of
separate systems.
Design decentralized
systems to minimize
impact of local flooding.
Education about hygiene
and cleaning up after
flooding.
Treatment and pumping systems cannot work if
electricity is affected.
Ensure that sewers are gravity flow wherever
possible. Low-cost and
shallow sewers have much lower pumping
requirements.
Local decentralized treatment will reduce
pumping costs and
enable local responsive management when
system is vulnerable to
damage.
High flows wash out
sewage treatment plant
and sewage pumping
stations.
Large populations
affected by flood
damage and
contaminated
floodwater.
Use sewage overflow
routing or storage to
protect treatment
processes and other
infrastructure.
Design decentralized treatment to minimize
damage to locality of
flooding.
Have spare parts
available.
Local management of
decentralized systems
may improve response
time for urgent maintenance and flood
protection.
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
Decentralize wastewater
systems to mitigate the
number of people
affected by shut downs
of sewers resulting from flooding.
Gravity only systems, shallow sewers.
Erosion exposing and
damaging pipe work,
especially simplified
sewerage.
Site pipe away from
drainage channel.
Compaction of soil and
planting above sewers,
under paved roads etc.
Adopt more conservative
design standards for
infrastructure to take more severe and more
frequent extreme
weather events into
consideration (the more
expensive option), or
have systems that can be
quickly and cheaply
replaced.
Low-cost sewers can be
more easily maintained
or replaced when
damaged, but are more
vulnerable to erosion.
Have spare parts available.
Increased risk of
landslides on steep slopes.
Damage to
infrastructure.
Build treatment works
and sewer networks away from slopes that
are at risk of slippage.
Reinforce slopes where
there is a risk of slippage that may damage
infrastructure.
Raise awareness about
the damage that landslides can cause to
infrastructure.
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
Implement leakage
reduction plan, as
leakage can contribute to
landslides.
Put in urban drainage.
Flooding causes damage to bridges and other
structures that support
pipes.
Adopt higher design standards for
infrastructure to take
higher and more frequent
floods into
consideration.
Install sewers on bridge
least prone to being
damaged by floods.
Install storm water tanks
to provide overflow
storage.
Have spare parts available.
Raise awareness about potential dangers
associated with physical
infrastructure failures.
Septic tanks
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
Back flow of sewage
into the house.
Install non-return valve
that can be shut in event
of a flood; do not use the
septic tank again until
waters have receded.
Regular emptying
services to minimize
faecal sludge build-up.
Raise awareness about
potential health issues
associated with sewage.
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
Inundation of the
system, resulting in
contamination of
surrounding area with
sewage.
Where possible, site tank
away from water supply.
Raise awareness about
potential health issues
associated with sewage.
Flooding of septic tank
resulting in accumulation of silt.
Design to prevent
ingress of silt.
Septic tanks and pump
chambers can fill with silt and debris, and must
be pumped out and
cleaned after a flood.
Ensure adequate access
to tanks so that they can
be cleaned.
Flotation. Structural damage to
tank, for example from movement.
Use durable materials in
construction of tanks.
It is important that tanks
are full of water during a flood to prevent damage
to the infrastructure.
However, lids need to be properly fitted and
secured to prevent
sewage overflow.
Education and increased
awareness of issues
surrounding damage and
when to replace.
Increased risk of
landslides on steep
slopes.
Damage to
infrastructure.
Avoid using soakaways
on slopes that are at risk
of slippage, as they can
contribute to landslides
(or ensure they are piped
away from the slope).
Reinforce slopes where
there is a risk of slippage
that may damage
infrastructure.
Raise awareness about
the damage that
landslides can cause to
infrastructure, and the
potential contamination
issues related to damage.
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
Erosion of soil around
the tank and absorption
field.
Damage to
infrastructure. Reduced
efficacy of the
absorption field.
Planting of grasses and
shrubs on the absorption
area, and around the
tank, to reduce erosion.
Repair erosion damage and sod or reseed areas
as necessary to provide
turf grass cover.
Build bunds (banks,
dykes or levees) to divert
flow away from system.
Check the vegetation
over the septic tank and
soil absorption field after
flooding.
Flooding of the
absorption field with
sewage sludge.
Install non-return valve
that can prevent flow to
the field in event of a
flood.
Inundation of the soakaway.
Delay using septic tank until flood waters and
groundwaters have
receded.
Educate about avoiding using the absorption
field until groundwaters
and floodwaters have receded.
Raise awareness of signs
of failure of an
absorption field, and
how to fix it or construct
a new one.
Improved pit latrines
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
Pit overflowing or
inundated; very mobile
contamination.
Faeces leaving pit and
causing pollution
downstream.
Silt and solids entering pit and filling it.
Design pit to allow regular
emptying and post-flood
rehabilitation to remove silt.
Proper pit covers to prevent material flowing out in a
flood.
Investigate overflow
mechanisms to filter water
to reduce pressure build-up.
Where possible, site latrine
away from water supply, and away from areas prone
to flooding.
Build pit latrine
superstructure at the same
level as the houses, as these usually are above normal
flood level.
In urban areas, consider
small pits which need
regular (monthly or less)
emptying to minimize the
amount of faecal matter
exposed to flooding.
Consider if dry or
composting latrines or sewerage is appropriate.
Regular pumping or
emptying of pit latrine
(particularly in urban
setting).
Monitoring and
regulation systems
should focus on
emptying and faecal
sludge management as well as construction of
latrines – to ensure that
systems are in place.
Raise awareness about
potential contamination
of drinking-water
supply and need for
regular emptying.
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
Increased intentional
emptying of pits during
floods.
Widespread
contamination with
faeces.
Regular pumping or
emptying of pit latrine
(particularly in urban
setting).
Monitoring and
enforcement systems
should focus on
emptying and faecal
sludge management, as
well as construction of latrines – to ensure that
systems are in place.
Raise awareness about
potential health issues
associated with sewage.
Raise awareness about
potential contamination of drinking-water
supply.
Inundation or erosion. Collapse of latrine. Site latrine away from
drainage channel.
Use durable materials in
construction to protect pit
covers.
Proper compaction of soil
around the latrine and presence of adequate base
and earth filling to protect
pits, pit covers and slabs.
Install robust upper
foundations, collar and
footing to protect from
erosion and flooding
damage.
Small pits in urban areas to
minimize risk of collapse.
Build bunds (banks, dykes
or levees) to divert flow away from latrine.
Regular maintenance
essential to limit
vulnerability to collapse.
Hygiene promotion.
Education on regular
maintenance
requirements.
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
Planting of shrubs around
the pit to reduce erosion
damage.
Adopt more conservative
design standards for infrastructure to take higher
and more frequent events
into consideration (more expensive), or have systems
that can be quickly and
cheaply replaced.
Damage to the
superstructure.
Make more durable,
especially the bottom 30cm,
or choose a cheaper
temporary option that can
be reinstalled rapidly.
Latrine not accessible. Find a new site, not subject to such frequent flooding,
or construct temporary
latrines in refuges.
Pit latrines sited in flow paths.
Filling up with water or overflowing.
Insert a bund. Seasonal emptying.
Increased risk of
landslides on steep
slopes, causing damage
to infrastructure.
Avoid building pit latrines
on slopes that are at risk of
slippage.
Reinforce slopes where
there is a risk of
slippage that may
damage infrastructure.
Raise awareness about
the damage that
landslides can cause to
infrastructure, and the potential contamination
issues associated with
damages.
Composting or dry latrines
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
Pit inundated. Faeces leaving chamber,
leading to pollution in
the environment.
Design toilet to be
appropriate to flooding
levels (e.g. above ground
chambers, rather than
small pits).
Capacity to restart
composting following
event. Redress moisture
balance.
Ensure that users know
they should keep
moisture out after
flooding.
Increased intentional emptying of pits during
floods.
Widespread contamination with
faeces.
Awareness of importance of not
emptying during floods
where there is no use of
compost.
Inundation or erosion. Collapse of latrine. Site latrine away from
drainage channel.
Use durable materials in
construction to protect
pit covers.
Proper compaction of
soil around the latrine
and presence of adequate
base and earth filling.
Build bunds (banks,
dykes or levees) to divert
flow away from latrine.
Planting of plants around the pit to reduce erosion
damage.
Adopt more conservative
design standards for
infrastructure to take
Regular maintenance
essential to limit
vulnerability to collapse
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
more severe and more
frequent extreme
weather events into
consideration (more
expensive), or have
systems that can be quickly and cheaply
replaced.
Damage to the
superstructure.
Make more durable,
especially the bottom
30cm, or choose a
cheaper temporary
option that can be
rapidly reinstalled.
Latrine not accessible. Find a new site, not subject to as-frequent
flooding, or construct
temporary latrines in refuges.
Pit latrines sited in flow
paths.
Filling up with water or
overflowing.
Insert a bund. Seasonal emptying.
Increased risk of
landslides on steep
slopes, causing damage
to infrastructure.
Avoid building latrines
on slopes that are at risk
of slippage.
Reinforce slopes where
there is a risk of slippage
that may damage
infrastructure.
Raise awareness about
the damage that
landslides can cause to
infrastructure, and the
potential contamination
issues associated with damages.
Key issue: Groundwater tables rising
Sewers
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
Sewer surrounded
by water.
Overloading.
Damage to sewer
(scouring or washout of bedding, and flotation
leading to cracking of
the sewer pipes).
Do not locate sewers in
soils which are regularly
waterlogged.
Low-cost and shallow
sewers may be less
susceptible and above groundwater levels.
Septic tanks
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
Flotation of septic tank. Damage to
infrastructure.
If groundwater rises
above the bottom of the
tank, the tank will need
to be secured to prevent
floating during pump-
out.
Education and increased
awareness of issues
surrounding damage and
when to replace.
Inundation of soakaway. Increased potential for
contamination of groundwater.
Treatment of sewage by soil in soakaways may
be reduced.
Use shallower
infiltration trenches or introduce artificial
wetlands or reedbed
systems to improve effluent treatment.
Monitor water quality
and groundwater levels.
Education to increase
awareness of the risks of sewage upwelling if
soakaways are
waterlogged.
Ensure that septic tanks
are emptied regularly.
Septic tank fills and
backs up.
Where possible, site
system away from water
supply.
Design septic tank
systems in conjunction
with drainage to lower the groundwater table.
Introduce trees and other
plants to improve
drainage and increase
water loss by
transpiration.
Education to increase
awareness of possible
contamination of water
resources.
Improved pit latrines
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
Inundation of the pit from below.
Contamination of groundwater and soil,
potentially reaching
drinking-water resources.
Provide protected water supply.
Consider options: shallower pits and more
frequent emptying;
dry composting latrines;
sewerage.
Regular pumping or emptying of pit latrine
(particularly in urban
setting) – link to smaller pit sizing.
Monitor drinking-water quality.
Education to increase marketing and user
education of alternatives.
Inundation of pit. Pit collapse. Build round pits instead
of square to increase
stability.
Use durable materials in
construction to protect pit covers.
Raise awareness about
the dangers of unstable
pit latrines, and under
what conditions these
might occur.
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
Proper compaction of
soil around the latrine
and presence of adequate
base and earth filling to
protect pits, pit covers
and slabs.
Install robust upper
foundations, collar and footing to prevent
collapse.
Small pits in urban areas
to minimize risk of
collapse.
Introduce trees and other
plants to improve drainage and increase
water loss by
transpiration.
Key issue: Water availability decreases Sewers
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
Less water available. Low or intermittent
flows may lead to
blockages building up
more quickly.
Increase attention to
construction quality and
setting out of sewers.
More inspection
chambers and rodding
eyes.
Steeper falls and
increased pumping.
Consider low-flush
toilets.
Low-cost, small-bore,
shallow, and solids-free
sewers (with interceptor chambers) all work
better with lower water
availability than
conventional systems.
Consider decentralized
wastewater systems.
Consider grey water recycling for toilet
flushing.
If no water available,
sewers will not be a
Adapt maintenance
programme to reduce
blockages and increase
flushing.
If low flows available,
investigate alternative
methods to flush out or
maintain sewers.
Local management of
shallow and low-cost
sewers.
Improve solid waste
management especially
for fat solids.
Monitor water
availability.
Monitor sewer performance for
blockages.
Educate people about
what is appropriate to be
flushed down toilets in
low flows. If necessary, advice may need to
include that paper cannot
be flushed down toilet.
Ensure that no waste
disposal units allowed in
sinks.
Educate people about
low-flush toilets.
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
viable option. Investigate
other systems for
management of human
excreta.
Less water availability. More concentrated
sewage at treatment
plant.
Adapt treatment
processes to be able to
cope with more concentrated sewage,
e.g. more stages.
Consider diluting flows
before treatment.
Design effluent
standards for the context.
Treatment processes that are appropriate may
change with drier
conditions, for example ponds or reed beds can
be used in dry
conditions.
Decentralized systems
can be managed more
responsively.
Plan for increased
operational expenditure
requirements, e.g. power.
Reduced flows in surface
water.
Decreased dilution
resulting in higher
pollution loads in downstream water
bodies.
Improve the treatment of
sewage before discharge
to receiving waters.
Adapt sewage discharge
infrastructure to be
Increase monitoring of
pollution.
Reconsider effluent
standards and adapt for
changes in potential dilution.
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
suitable for low flows.
Consider design of
downstream water
supplies to take account
of increased pollution loads.
Reduced water for
irrigation.
Increased wastewater
use, and use of polluted
receiving waters.
Design distribution
system for wastewater
and an appropriate level
of treatment.
Consider disposal during
wet season.
Establish an appropriate
pricing scheme.
Health surveillance and
food quality monitoring.
Education to increase
awareness of possible
contamination of water
resources.
Changing moisture
levels in soils.
Movement and
infrastructure damage.
Design for movement,
e.g. shorter lengths of
pipes; or use non-reticulated systems on
site.
Adapt maintenance
programme to identify
breakages.
Monitor sewer
performance for
blockages and breaks.
Septic tanks
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
Less water available for
flushing and cleaning.
Toilet and discharge pipe
becomes dirty or
blocked.
Examine lower-water
use approaches (plastic
seals rather than water seals, for example) and
slabs that are easier to
clean.
Increase attention to
construction quality and setting out of sewers.
Consider feasibility of
households doing more
regular cleaning, rodding etc.
Improve solid waste
management, especially
for fat solids.
Septic tank system
inspections.
Education and awareness
of lower-water use
latrine options.
Educate people about
what is appropriate to be
flushed down toilets in
low flows. If necessary,
advice may need to include that paper cannot
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
More rodding eyes.
Steeper falls.
Consider low-flush
toilets.
If no water available,
septic tanks will not be a viable option. Investigate
other systems for
management of human
excreta.
be flushed down toilet.
Ensure that no waste
disposal units allowed in
sinks.
Educate people about
low-flush toilets.
Increased distance to
groundwater tables
Reduced risk of
groundwater pollution
Septic tanks become
more viable option
Changing moisture
levels in soils
Movement and
infrastructure damage
Design for movement. Adapt maintenance
programme to identify
breakages.
Monitor performance for
blockages and breaks.
Improved pit latrines
Adaptation methods Vulnerability Impacts
Capital expenditure Operational expenditure Monitoring Socioeconomic tools
Less water available for
flushing and cleaning.
Toilets become dirty or
blocked.
Examine lower-water
use approaches (plastic
seals rather than water seals for example) and
slabs that are easier to
clean.
Consider feasibility of
households doing more
regular cleaning.
Latrine inspections. Education and awareness
of lower-water use
latrine options.
Minimum standards for
slab construction.
Increased distance to
groundwater tables.
Reduced risk of
groundwater pollution.
Pit latrines become more
viable option.