United Nations
Commission on Sustainable Development

Background Paper

       Strategic Approaches to Reduce the Impacts of Natural Disasters 
                    on Freshwater Resources and its Supply



      A.   General
      B.   Background


      A.   Extreme Hydro-meteorological events
            1.   Floods
            2.   Droughts
            3.   Storm surges

      B.   Effects of Climate Variations and Climate Change
            1.   El Nin~o
            2.   Climate Change

      C.   Geological Catastrophes
            1.   Earthquakes
            2.   Volcanoes

      D.   Human Induced Disasters
            1.   Pollution


      A.   Structural Measures
      B.   Non Structural Measures
      C.   Emergency Response


      A.   Conclusions
      B.   Recommendations and Priority for Strategic Action
            1.   Growing Awareness
            2.   Integrated Freshwater Resource Management
            3.   Generation of Financial Resources
            4.   United Nations Responses in Support of Actions


                                 A.   General

1.    The primary goal of natural disaster reduction is to lessen the impact
of hazards on human lives.  One of the most severe hazards causing natural
disasters is that of floods. Yet ironically, droughts are also an important
cause of natural disasters.  Water management is therefore an important issue
in natural disaster reduction.

2.    Water is the most valuable resource for societies: an essential
component of welfare and productivity. The world■s agriculture, hydroelectric
power production, industrial needs, inland navigation are dependent on the
natural endowment of surface and groundwater resources. Reducing the impacts
of natural disasters on water resources is therefore necessary for sustainable

3.    All natural disasters have impacts on water resources. Their protection
should systematically be taken in account within preventive and mitigation
measures. Distinction should be made between water-related disasters and
disasters affecting water resources. «Water-related disasters» is a term
referring to floods and droughts, i.e. disasters which find their origin in
hydro-meteorological extreme events but this term does not specifically
include their impacts on water resources, even though both are closely linked.
Nevertheless, other disasters such as earthquakes and volcanoes have also
dramatic effects on water management and freshwater supply.

4.    Progress in the field of integrated water management, could at present,
allow us to cope with the complexity and specificity of natural disasters
caused by extreme hydrological events. The present document is an attempt to
deal comprehensively with the impacts of natural hazards on water resources
and freshwater supply, and proposes strategic approaches to reduce them. 

                                B.   Background

5.    This document is a joint International Decade for Natural Disaster
Reduction (IDNDR) / World Meteorological Organization (WMO), contribution to
the sixth session of the Commission on Sustainable Development (CSD) scheduled
to meet in April 1998. It provides an input for the Report of the Secretary
General on Strategic Approaches to Freshwater Management.

6.    Disaster prevention and mitigation with regard to freshwater is an issue
addressed in Agenda 21 (United Nations Conference on Environment and
Development ; Rio, 1992) : «Water resource management must be developed within
a comprehensive set of policies for (i) human health; (ii) food production,
preservation and distribution; (iii) disaster mitigation plans; (iv)
environmental protection and conservation of the natural resource base...»

7.    Following recommendations from various reports mentioning the need for
water-related, or more specifically, freshwater resource-related disaster
mitigation and preparedness, IDNDR is honoured to provide this document in
line with the Mar del Plata Action Plan (Argentina, 1977), the International
Drinking Water Supply and Sanitation Decade (1981-1990), the Technical
Conference on the Hydrology of Disasters (WMO, 1988), the Dublin
Statement (International Conference on Water and Environment, 1992), and in
accord with considerations of the Committee on Natural Resources of the
Economic and Social Council (see E/C.7/1994/2).

8.    The impacts of natural disasters on water management will be reviewed in
the first section. The current methods in water-related risk management will
be presented. In order to face new challenges and risks associated with the
21st century development requirements, recommendations for priorities in
strategic actions for protecting water resources and freshwater supply will be


                   A.   Extreme Hydro-meteorological Events

                                  1.   Floods

9.    Floods are the most common cause of natural disaster and lead to the
greatest number of deaths and the most physical damage. However, even if
floods are perceived as causing the most severe water-related disasters, their
potential impact on water supply and water-resource management is often not
taken adequately into consideration in disaster prevention activities.
The reason for this is that priority is generally given to the protection of
lives and property. It is also because in times of abundance of water, access
to drinkable water is often not questioned.  The excess of water during floods
is difficult to use because it is often contaminated by mud and other
pollutants.  This water should be carefully stored in reservoirs
and purified, especially since floods can destroy water purification and
supply systems.

10.   A flood plain is land situated next to a river and directly subject to
flooding. Because flood plains are generally flat, located near water and
usually fertile, they have been attractive places for human settlements and
development since the dawn of civilization despite the risk of loss of
property and lives from flooding. Flood plains, through their multiple
ecological functions, naturally control flood and erosion by reducing flow
velocities, flood peaks and by stabilizing soils. They also maintain the
supply and quality of groundwater by promoting infiltration and aquifer
recharge and by increasing base flows. Finally, by reducing sediment
loads, filtering nutrients and pollutants, processing organic and chemical
wastes, and by moderating water temperature, they maintain surface water

11.   Therefore, in addition to protecting developments in the flood plains
from loss, any flood plain management plan should also aim to protect the
natural and cultural resources located in the flood plain. The protection of
these resources will not only lead to the maintenance of a good quality water
supply but will also preserve the natural flood-alleviating functions of the
flood plains. In view of such facts, flood control measures presented in
paragraph II, should not only aim to protect lives and property but should
also integrate the protection of water resources and supply. Such measures
will be proposed in chapter III.

                                 2.   Droughts

12.   Droughts and floods are at opposite hydrological extremes. While water
is regarded as a given, something to be taken for granted, in some countries
where water shortages almost never occur, it is something rare and precious,
for example in Africa, in small island developing states (SIDS), and in
developed countries such as in the USA and Australia. 1997■s World Day for
Water (WMO - 22nd March 1997) was being undertaken on the theme "Water
Resources Assessment", and with the slogan: "The World■s Water - Is there
enough ?". Even though this questions remains an open one, when considering
future global aspects of water use in relation to increased urbanization,
population density and industrialization, the answer is definitely negative
for some parts of the world today.

13.   Droughts are a consequence of the combined lack of the runoff to rivers,
precipitation and groundwater resources. The consequences of droughts are felt
most keenly in arid areas. However, drought should not be confused with
aridity nor with desertification which might be caused by land abuse. Droughts
occur on all continents (Chile, Mexico, India, and China), though recently the
most devastating drought occurred in the Sahel Desert of Africa. Development
in these countries is hindered by droughts. 

14.   Deforestation and overgrazing in many countries of the world lead to
desertification. Therefore, desertification in addition to climate change,
make the problem of droughts a global one. However, well managed lands will
recover from droughts with minimal adverse effects if the rains return. On the
other hand, the combined effect of drought and land abuse may lead to faster
erosion, faster run-off of river water and larger floods without
replenishment of the aquifers if the rain returns. 

15.   The problems of floods and droughts are two-fold :
      - they are both hydrological extremes related to weather and
climate ;
      - their impact can be worsened by careless human activity.
As will be seen in chapter II, measures to reduce their impacts can be
studied jointly since for both, it is necessary to store water, to
control its flow and to enhance its infiltration in the soil. Their
relation with climate can also be approached simultaneously.

                               3.   Storm-surges

16.   Many floods in coastal areas and in river estuaries of a continent or an
island are due to storm-surges which result from the sea being driven onto the
land by meteorological forces. Storm-surges are commonly associated with
tropical cyclones but they can occur with any intense storm. Flooding due to a
storm-surge can have destructive effects, even more than the strong winds.
Wave action, normal tides and storm-surges can have a combined effect
resulting in high-water levels which can be damaging. Buildings, roads and
public utility services may be destroyed or disrupted. Powerlines may be
downed by the storm and desalination units may be disabled. Water storage
tanks may be destroyed and sewage treatment systems disabled. 

17.   The violence of a storm-surge is most often be followed by water
scarcity. Not only may water-supply systems be disrupted for several months,
but the intrusion of saltwater would burn grass, kill bushes and affect the
freshwater resources. Water quality may be affected after a storm-surge and
many fish and shellfish may perish. Aquatic habitats may be disturbed by
physical disruption of the shoreline, freshwater flowing into lagoons as a
result of the plentiful rains. 

             B.   Effects of Climate Variations and Climate Change

18.   Floods and droughts, even if local phenomena, can be related to
large-scale or global climate mechanisms. Climate variations is a term
referring to «year to year» or inter-annual fluctuations in the annual cycle,
including also anomalous cycles ranging from two to ten years in duration.
Climate variability persistent over a ten years period is referred to as
climate change. Through the study of atmospheric teleconnection mechanisms
between remote areas of the planet, scientists are now increasingly able to
link extreme weather events such as droughts and storms with climate
variations and climate change. 

                   1.   El Nin~o-Southern Oscillation (ENSO)

19.   One of the most spectacular climate variation consequences is El-Nin~o.
The El Nin~o event, a warm water current along the coast of Peru and Chile, is
part of a climatic phenomenon known as the El-Nin~o-Southern Oscillation
(ENSO) which strongly affects tropical and mid-latitude countries. Impacts of
ENSO are droughts over southeast Asia, heavy rains in the tropical Pacific and
the west coast of the Americas at tropical and mid-latitudes. At the same time
droughts appear further east, over northeastern Brazil and southern Africa.
The generation of ENSO is not yet fully understood. Its recurrence interval
varies from two to seven years, with an average of four years.

                              2.   Climate Change

20.   The Working Group II of the Intergovernmental Panel on Climate Change
(IPCC, 1995) concluded that: «There is evidence, from climate models and
hydrological impact studies, that flood frequencies are likely to increase
with global warming». Global warming can be expected to produce changes in the
frequency of intense rainfall. Higher sea-surface temperatures can be expected
to increase the intensity of tropical cyclones and to expand the area over
which they may develop. Rainfall intensity is likely to increase with
increasing greenhouse gas concentrations and there may be an increasing
concentration of rainfall on fewer rain days. 

21.   Changes in the magnitudes of snow-melt and rain-on-snow floods will
deserve particular attention in some temperate regions ; floods caused by
snow-melt may increase. Impacts of climate change are expected to be greater
on Tundra Lands and in alpine regions. Deglaciation on temperate mountains
would increase sediment loads in alpine rivers and accelerated sedimentation
in lakes and artificial reservoirs. Lakes dammed by landslides, moraines and
glaciers may drain suddenly and produce floods or debris flows of an order of
magnitude larger than normal stream flow. Less snow and glacier ice will
influence the seasonality of river flow by reducing melt-water production in
the warm season. The expected smoothing of the annual runoff amplitude could
be both beneficial (e.g. energy production in winter, reduction of summer
flood peaks) and adverse (e.g. reduced water supply for summer irrigation in
dry areas, more frequent winter floods). The general tendency in high
mountains will be an increased vulnerability of people, transport routes, and
economic infrastructures. 

22.   As climatic warming occurs, there will be notable changes in the
hydrology of Arctic areas. River-ice regime might be altered and substantial
effects on the hydrology can be expected that will affect flow, water levels,
and storage. For cold continental rivers, many hydrologic extremes, such as
low flows and floods, are frequently more a function of ice effects than
landscape runoff. Projected climates will delay the timing of freeze-up and so
prolong the autumn low flow period. At break-up, the rapid hydraulic storage
and release of water by river-ice jams often forms the most significant
hydrologic event of the year. Of all river-ice processes ice jams are the
major source of economic damages. Changes in damages from such events depend
on how climate change affects the frequency and severity of river-ice
freeze-up and break-up events. 

23.   Drought has generally received little attention, but it is reasonable to
think that an increase in the frequency and intensity of floods may be
associated with an increase in the occurrence and severity of droughts in
order to compensate the first extreme and to reestablish the natural energy
and water balance. 

24.   It thus appears that progress in climatology and in the development of
numerical models not only enable scientists to relate extreme weather events,
such as floods and droughts, with climate variations like ENSO, but they can
give some insight to climate change scenarios due to global warming, such as
sea level rise and changes in frequency, strength and geographical
distribution of extreme events. These results should be of great help in
taking the right measures and in building up the adapted policies. 

25.   In view of possible climate change scenarios, natural disaster
prevention and mitigation have an even greater importance.  It is now possible
to build up policies based on climate studies results, in order to get ready
for the expected impacts of climate change. Until now, states and societies
have learned from the past and may be, more or less, prepared to face
certain events which are recurrent. But up-to-date measures and policies will
no longer be sufficient if the intensity of extreme events increases and if
their geographical distribution changes. The uncertainty brought on by climate
change will have to be taken into account in risk management.

                         C.   Geological Catastrophes
                               1.   Earthquakes

26.   Recently, urban growth in areas with a high risk of seismic activity has
highlighted the risk of disruption faced by resources and water supply
infrastructures. This risk is particularly important when considering that the
increasing population density of certain cities is already reaching the limits
of water resources available. The rapid industrial expansion as well as the
increase in waste waters also create serious pollution hazards in earthquake
prone areas. 

27.   The impacts of earthquakes on water management and development include
dam failure, and the ensuing flooding. This is particularly relevant since
large reservoirs may increase the seismicity of certain areas. Water pipelines
might also be disrupted. The resulting water cuts will affect the emergency
response. The damaged water system will, with time, increase, the number of
casualties for a given earthquake.

28.   Water leakage due to the fissuring of the pipelines and water reservoirs
associated with ground deformation and soil failure may also occur. The
resulting rise in groundwater levels under a city may result in subsidence and
an increase in the risk of liquefaction during the aftershocks. The risk of
pollution due to the collapse of liquid storage tanks and other industrial
installments are to be considered as well. 

29.   In many areas, water for irrigation, domestic and other uses, is
transported in large quantities through open aqueducts. Ground shaking may
result in negligible local damage or readily repairable failures, but a major
earthquake would destroy such aqueducts and restoring them to full capacity
may require many months. Water wells may also be affected by earthquakes, when
drilled in unconsolidated material. These wells can be severely damaged
through strong ground shaking, lateral displacement, and high ground

                                2.   Volcanoes

30.   An erupting volcano may, of course, destroy nearby water supply
structures. Specific to volcanoes are, however, the ash clouds with
accompanying pyroclastic flows which may pollute the water resources and cover
catchments over a large area, making water unusable for a long time after the

31.   Rivers originating from volcanic zones may have varying chemistries
which can affect aquatic ecosystems downstream and subsequently, fisheries.
Another natural disaster resulting from volcanic activities is the risk of
flooding due to the melting of snow and ice on the flanks of a volcano with
ensuing mud flows and landslides.

                         D.   Human Induced Disasters

                    1.   Water pollution and contamination

32.   Water is necessary for industries which are therefore often located near
a river. Thus, natural disasters may not only affect the water resources and
their management directly but floods and earthquakes may also destroy
industries producing or using toxic materials or dangerous chemicals which
might be released into floodwaters. The polluted water may cause death or
diseases by poisoning. 

33.   Such catastrophes, even if induced by natural phenomena, are not «
natural » in themselves. Their origin is human industrial activity and they
can be avoided through properly applied policies and good decision making.
With increased urbanization, increase in population density and
industrialization, the problem of pollution might also become more

34.   Worldwide, considerable disease is linked to the interrelated problems
of water quality, water availability, sanitation and hygiene. A reduction in
water supply could reduce the water available for drinking and washing, and
lower the efficiency of local sewage systems, leading to increased
concentration of pathogenic organisms in raw water supplies. Additionally,
water scarcity may necessitate the use of poorer quality sources of
freshwater, such as rivers, which might be contaminated. Warming of
above-ground piped-water supplies also affects water quality through the
proliferation of amoebas.  

35.   Aquatic ecosystems such as ponds and wells, and irrigation and drainage
systems, provide breeding grounds for certain parasites or disease vectors.
Natural networks of rivers, lakes and marshes, also play a role in the
transmission of water-related and vector-borne diseases. If these undergo
increased flooding, community water supplies could become contaminated,
leading to greater incidence of faecal-oral diseases such as cholera, typhoid,
hepatitis A and diarrhea. 

36.   Developing countries are at most risk with respect to waterborne and
water-washed diseases, and urban communities are at greater risk than rural

37.   Following a flood, sanitation problems due to disruption of water or
sewage systems and prevention of solid-waste collection and disposal, often
contribute to increased infectious disease incidence and may kill people
particularly through watery diarrhea. 

38.   Any increase in heavy precipitation and consequently in runoff from
agricultural lands, would also be likely to increase contamination of water
with chemicals such as pesticides. Human exposure to toxic agents and
chemicals from agricultural lands and industrial sites may then occur if water
or animals that have become contaminated are consumed. Chemicals
may also persist for a longer period of time in flooded soils than in
non-flooded soils.

                             II.   RISK MANAGEMENT

39.   As most disasters are specific to certain locations (flood plains,
unstable slopes, seismic regions, in proximity to volcanoes, arid regions), a
primary form of prevention consists of avoiding as much as possible these
particularly dangerous areas. Such a measure is called « non-structural » in
opposition to structural measures, which are protective works (such as dams,
dikes, and levees). In the next chapters, both types of measures will be
presented with their application to water management from the resource to its

                           A.   Structural measures

                                  1.   Floods

40.   Structural measures to limit the effect of floods include the
construction of dikes, flood banks or levees to divert the flood waters ; dams
and reservoirs to retain flood waters upstream ; and channel improvements to
evacuate flood waters more rapidly. These measures have proved to be very
effective in saving lives and property, but they are often expensive,
both to build and to maintain. An advantage of structural methods is that they
can be effective in protecting existing developments on the flood plain. By
contrast, many non structural measures may only benefit new developments. 

41.   However, structural measures protect losses only up to a certain level
of risk. Precaution should be taken that a false sense of total security is
not created in people■s mind. If dams and dikes are built to protect the flood
plain from a « 100-year » flood (i.e. a flood which intensity appears, in
average, once in hundred years) and that a « 500-year » flood occurs,
inundation may most certainly not be avoidable.

                                 2.   Droughts

(a)   Surface Water Management

42.   Structural measures to limit the consequences of hydrological droughts
are similar, in their concept, to those that can be taken for floods. The use
of reservoirs for storing the excess flows from wet years is even more
important when coping with droughts. But this is not always practical in arid
and semi-arid zones where a great deal of stored water is lost through
evaporation. Natural drinking ponds are typically very shallow in such regions
were 95% of the water is lost by evaporation. One solution lies in increasing
the depth of water by creating small deep artificial reservoirs within these
natural ponds. A second solution for these same arid and semi-arid areas is to
construct small reservoirs in the upper reaches of intermittent streams or to
use covered cisterns supplied by natural or artificial impermeable

(b)   Groundwater Management

43.   The use of surface water supplies is, however, not always possible
during severe droughts, so it is necessary to make use of available
groundwater resources. Groundwater is less sensitive to evaporative loss and
sometimes entirely unaffected, when deep enough. During hydrological droughts,
the use of groundwater is general in all countries. Too large a depletion of
the aquifer, or its total exhaustion, before the end of drought must be
avoided. In countries at all levels of development, aquifer levels are being
lowered to dangerous levels by excessive or unsustainable demands, causing
land subsidence, saline intrusion and degradation of the fissure network. To
avoid overexploitation of groundwater resources requires the quantification of
existing water resources and the optimization of their use. Structural
measures to optimize groundwater management are the artificial augmentation of
aquifer recharge which can take two forms :

      - increasing the area covered by the floods in arid countries and
      also increasing the duration of  the submersion using a small dam
      and diversion channel ;
      - directing water to wells, or to locality of very high
      infiltration capacity.

                         B.   Non-structural measures

44.   Non-structural measures include all measures related to policy
determination and application such as physical planning (zoning, urban and
regional planning, building codes). Other mechanisms, especially in developed
countries, would include the use of financial instruments, such as mortgage
policies, loans or subsidies for housing or the development of business or
insurance as incentives for prevention. Early warning using forecasts are also
useful non-structural preventive measures all the more because predictions are
progressively more accurate.

                                  1.   Floods

(a)   Flood plain management

45.   The non-structural flood defense measures to be considered here include
land-use planning and zoning to control the use of flood-prone areas,
flood-proofing of existing structures, soil and water conservation to reduce
flood flows, and forecasting and warning systems. Among these non-structural
measures, the most important one is the control of flood plain development.
Flood plain maps indicate the areas with high flood risk and are used as
the basis of flood plain management. They show where development needs to be
controlled if flood damage is to be reduced. A variety of methods is available
for controlling development and the particular methods adopted will depend on
the legal and administrative systems of the country. Usually, control will
involve some sort form of land-use regulations. 

46.   The regulations do not need to prohibit all development on the flood
plain. A feature of use in most flood plains is that designated activities can
be interrupted at flood times with only relative inconvenience. Incentives to
choose safer areas, when possible, should be given for developments that would
suffer greater from floods (e.g. agriculture, camping or hotels).
On the other hand, there are facilities that should never be located in the
flood plain because they will be needed in times of flood emergency. These
include hospitals, telephone exchanges, electricity sub-stations and emergency
control centres and water supply systems.

(b)   Floodproofing

47.   Floodproofing is a means of protecting individual structures from the
effects of flooding and consists in elevation above the flood level, and flood
walls. These are used to protect houses but can be applied to water plants and
purification systems too. Water supply and sewage systems must be safe from
flooding and designed to prevent contamination of flood waters.

(c)  Soil and water conservation

48.   The aim of soil and water conservation is to catch more water close to
the place where it falls. Such measures are important since human activity
often reduce infiltration by increasing runoff and erosion in catchments.
Reforestation, terracing, contour ploughing, small ponds or farm dams are
beneficial measures to the soil and the water. Promoting a good deep
soil profile, capable of storing a substantial volume of water, with a healthy
cover of vegetation, whether trees, crops or grass, can only reduce flooding
and increase flows during dry periods, thus making the water more readily
available for human use.

(d)   Flood forecasting and warning systems

49.   Flood forecasting is based on weather forecasts, telemetry network,
radar and satellite data, river gauges network. Input data and model results
can be displayed graphically for the use of the forecasters and telexes, faxes
or e-mails, for sending forecast results to the end-users can be generated

50.   The general population also needs to know how to respond in case of an
emergency and this requires well organized preparedness. The warnings are
disseminated to the population by official announcements through the radio and
television and through official channels. However, people often fail to heed

                                 2.   Droughts

51.   Non-structural measures to reduce the impact of droughts are also very
similar to those mentioned for floods. Land-use and management, logistical and
social measures for mitigating drought consequences are most practical and
effective. In the developed world, an important objective of drought planning
is to diversify activities to include drought tolerant ones such as
industry and tourism. In the less developed world, the theory of integrated
development of drought response fails to take into account the existing
cultural, social and economical environment. Inappropriate technology, human
and stock disease, inadequate infrastructure, all stand as obstacles to the
actual implementation of a sophisticated drought plan. 

52.   Everything that might obviate the catastrophic consequences of droughts
should be attempted. The first set of measures concerns the improvement of the
availability of water during the drought by artificial modification of surface
flows, by a greater or better utilization of groundwater, or by a combination
of the two. The reduction of water losses is also important and consist in
reducing the losses in the irrigation system or reticulation network of
domestic water supply and reducing evaporation from water surfaces. 

53.   Unhappily, it has been found impossible to meet water needs during the
more severe droughts strictly by technical means. Measures other than the
purely technical ones should be taken including : food storage during wet
years, insurance, international help. 

54.   Many of these measures require international efforts, for instance, the
integrated management of large basins, or aquifers which straddle national
boundaries. Of equal importance is the international effort needed for the
selection and marketing of agricultural products. One should also stress the
international role of transmitting experience and technology from one country
to another, from developed countries to developing countries and also between
developing countries facing the similar problems. 

55.   Finally, there is hope for better prevention and preparedness through
the progress of climatological studies dealing with the hydrological cycle.
Research would result in a better understanding of the physical mechanisms of
the distribution of, and the contents of atmospheric water vapor. Knowledge on
freshwater fluxes between the atmosphere and the ocean is also necessary for
the study of precipitation and evaporation patterns. Such studies could help
to predict floods and droughts better through the understanding of
teleconnection between remote areas (i.e. remote cause and effect relations).
When coupled with hydro-geological studies, they could also enable enhanced
groundwater management practices to be employed.

                            C.   Emergency response

56.   No system of defense can protect against all hazards nor achieve a zero
risk-level. The marginal cost of reducing each additional increment of risk
typically rises rapidly as reliability approaches 100%. Hence, decision makers
usually deal with 90%, 95%, and 99% levels of reliability as useful
performance measures of the available quality and quantity of water.
Emergency measures are therefore necessary. 

57.   Emergency response systems are more or less similar for any natural
disaster and involve the same civil defense personnel, first to educate, then
to alert the population and, when necessary, to help protect them. In the case
of an emergency, response should take in account the possible scarcity of
water after a disaster, and advance storage should automatically be part of
emergency measures.


                               A.   Conclusions

58.   A natural phenomenon, however violent, does not necessarily cause a
disaster: there is a disaster only if the phenomenon in question strikes an
unprotected or poorly protected human settlement resulting in the loss of
lives. Loss of lives may also occur when drinking water is absent or polluted.
In general, most countries and societies have faced drinking water
shortages due to natural weather and climate variability (floods and
droughts), earthquakes and volcanoes, desertification, overexploitation and
pollution of the resource base. Therefore, management of water resources
inherently entails mitigating the effects of hydrological extremes and
providing a greater degree of reliability in the conservation and delivery of
water-related services. 

59.   Water management consists in protecting the water resources and
developing its distribution. It should therefore include measures to prevent
the loss of water resources and to protect freshwater supply sources and
systems from natural disasters and their consequences, in particular,
pollution, due to human activity. Some measures to prevent from and reduce the
impacts of the main natural disasters have been described in the previous
chapters. Even though significant progress has been achieved in disaster and
water management, especially in developed countries, natural hazards are
suspected to become even more hazardous, due to climate change. Structural and
non-structural measures taken in response to past events might no longer be
sufficient alone to cope with more intense or geographically altered
water-related disasters. 

60.   Moreover, adequate supply of freshwater may be one of the most
challenging problems of the next century : water is not only scarce in arid or
semi-arid areas, but is becoming an increasing problem in urbanized regions,
because of increase in population density, industrialization and pollution. 

61.   As adopted at the Nineteenth Special Session of General Assembly
(September 1997), Resolution S-19/2 of the -Programme for the Further
Implementation of Agenda 21■ recommends that « programmes for sustainable
development should give higher priority to the implementation of the
commitments made at the World Conference on Natural Disaster Reduction held at
Yokohama, Japan from 23 to 27 May 1994. » (see A/CONF.172/9 and add.1).
Paragraphs 73 to 75 refer to -natural and technological disasters with an
adverse impact on the environment■, and urge for the strengthening of coping
mechanisms and policies designed to reduce the socio-economic impact of
disasters, in particular an appropriate transfer of technology and adequate
early-warning systems. Further recommendations for action are proposed in the
next chapter, in order to give higher priority to natural disaster
prevention and mitigation, within the framework of freshwater resources
management and supply.

            B.   Recommendations and priority for strategic actions

                            1.   Growing Awareness

62.   A disaster is not an unavoidable phenomenon - it is an extreme act of
nature which, often complicated by human activity, severely impacts human
lives.  Although not much can be done to prevent natural phenomena such as
floods and earthquakes, human activities can modified to become more
harmonious with their natural environment, in order to reduce the
hazard's impact. This applies to all human activity - from that of
individuals, to communities, to nations. 

63.   Of course, natural disasters cannot be predicted with a great deal of
accuracy, and there is always the risk that they could strike anywhere, at any
time.  Societies prepare for such risks through the acceptance of certain
levels of risk and reliability - as explained above, water managers usually
deal with 90%, 95% and 99% levels of reliability. These levels of risk
and reliability are based on an analysis of cost effective standards, and on a
goal of zero loss of lives.  However, societies■ prevention and preparation
mechanisms are faced with increased risk due to the uncertainty brought on by
climate change and because of urbanization, increase in population density and

64.   A 1% risk, i.e. the risk that a disaster occurs, on average, once in
hundred years, may not be a valid concept anymore. Therefore, any false sense
of security in the population should be erased through prevention. While some
populations may be familiar with water scarcity and recurrent natural
disasters such as cyclones or floods and droughts, a very high number of
people not only in developing countries but also in developed countries, have
no knowledge of emergency response. 

65.   To ensure that a culture of prevention prevails in the twenty-first
century century, IDNDR proposed a Action Plan 1998-1999 which was endorsed by
all Members of the Scientific and Technical Committee for IDNDR at its ninth
session, held in Geneva from 13 to 17 October 1997 and positively presented
the 3rd November 1997 at the fifty second session of the General Assembly 
under Agenda item 98 (d), (A/52/560). 

66.   One important aspect of the Action Plan 1998-1999 relates to the
anticipation of the kind of disasters likely to prevail in the twenty-first
century. Early warning, as well shared knowledge and technology issues are 
primary themes of the plan upon others based on the original aims of the
Decade. Successful early-warning depends on translating technical and
scientific knowledge into an understandable message that informs a political
decision-making process. Early warning is therefore a cross-cutting issue, and
the role of the Decade■s programmes as a bridge between science and the users
is vital. (see A/52/561).

                2.   Integrated Freshwater Resources Management

67.   No matter how effective water policies may have been in guiding water
resources management over the past decades, such policies may no longer be
suitable for meeting the challenges of the next century. 

68.   At a national level, water resources management is typically divided
among a number of governmental sectors and/or ministries. This means that
water policies are not the exclusive domain of water as a resource sector but
overlap with other sectoral policies. In many countries, the ministry of
agriculture has purview over irrigation, and many policies concerning this
extremely important water use are established by this agency. Similarly, other
water use such as hydroelectric power and navigation are the policy domain of
the ministries of energy and transport. Urban and rural water supply and
sanitation are often concerns of the ministries of health and human
settlements, while environmental agencies establish policies for
water quality and preservation of natural aquatic ecosystems, and forestry
agencies are often involved in watershed management activities which have
major repercussions on water resources. In addition, macro-economic policies
on finance, budgets and trade can have important impacts on water resources

69.   Since a natural disaster affects all sectors, there is a need to develop
an overall water policy based on appropriate land-use management. To alleviate
human induced droughts and floods, occurring on a regional scale due to
inappropriate land-use practices, standards for land-use should be developed
to minimize erosion and maximize the interception and infiltration of water. 
These standards should be developed in cooperation with the aid of the
scientific community. 

                    3.   Generation of Financial Resources

70.   Money may be a leading constraint for the improvement of water
management and freshwater resource protection. One way of dealing with the
financial problem and to obtain the needed additional funds would be through
charges for water pollution or for water consumption. However, most of the
people who are currently unserved by water supply in developing countries are
poor and unable to pay the full cost of additional services. Since
water is crucial for development in any country, public, governmental and
international commitment to water management and freshwater supply should be
increased as a high priority investment. 

71.   Increased flood frequencies probably would lead to increased
expenditures on flood management. There is a lack of information about the
economic impact of droughts and therefore, only marginal interest exists in
planning for droughts. The magnitude of drought impacts is assumed to be less
than that of other natural hazards because losses associated with
other natural hazards are more evident and generally are incurred during short
periods of time. In contrast, drought losses generally are distributed over
longer time periods. When the true costs of drought are known, drought losses
can dwarf the losses from other natural hazards. 

72.   The World Bank has laid out a framework for water resource management
that is expected to serve the needs of developing nations well into the next
century and to meet objectives of Agenda 21 of the Rio Conference on
Environment and Development. At a regional level, some banks have also become
aware of the need for proactive mitigation measures before disasters strike
and include vulnerability analysis and risk assessment in their

73.   At the global scale, the international insurance and reinsurance
industry may be seriously threatened by global warming effects. The primary
purpose of insurance is, of course, to pay for the damage caused by a
disastrous event, but it is also often recommended as a means of good
development. Insurance could be a useful tool for preventive measures if
its cost is in proportion with the risks. It could thus encourage people to
settle or to move in safer areas. 

74.   In most developing countries, the full cost of insurance in high-risk
areas is too financially burdensome for many property owners. Insurance
premiums must be based on a full assessment of risks, for instance, with the
use of mapping data. In developing countries, this assessment is usually
lacking and the general interest for buying such insurance policies is
low. Therefore, it is difficult to control construction of economic structures
in high-risk areas of most developing countries except through incentive

75.   By encouraging the protection against natural disasters, through loans
or assistance for housing or business, the government can also implement
prevention measures and, in so doing, create the conditions for a culture of
prevention to develop.

              4.   United Nations Responses in Support of Actions

76.   The International Decade for Natural Disaster Reduction (IDNDR),
launched its 1997 public awareness campaign around the theme « Water - Too
much...Too little...Leading Cause of Natural Disasters ». It aimed to raise
the awareness of the fact that unsustainable development patterns that ignore
sustainable water management are exposing urban and rural communities to
greater risks. 

77.   IDNDR has established a regional office for Latin America and the
Caribbean. This helped to raise regional interest in making prevention and
mitigation measures a development priority, in particular in the health
sector. An IDNDR proposal for « Disaster mitigation and preparedness for water
supply systems in Latin America and the Caribbean » has been elaborated
together with the Pan American Health Organization (PAHO), a regional office
of the World Health Organization (WHO). The project is funded by Germany and
its objective is the prevention and mitigation of damages caused to water
supply and sewage systems (treatment plants and pipelines). 

78.   Since water is essential for sustainable development, prevention and
mitigation measures to reduce the socio-economical impacts of natural
disasters should include the protection of water resources and of freshwater
supply. Conversely, water managers should take into account the prevention and
reduction of water-related disasters. This could be achieved through the
implementation of similar projects as the one conducted in Latin
America and the Caribbean. 

79.   Newly observed phenomena, such as the possibility of long term climate
change with the expectation of disastrous effects on a global scale or, on a
shorter term, the irregular occurrence of El Nin~o- Southern Oscillation,
create further uncertainties and new challenges for institutionalized warning
practices. The combination of the forces of natue with the ill-considered, or
uncontrolled, behaviour of humankind, can easily increase the vulnerability of
communities and threaten the assets on which they must depend. 

80.   In that context, the General Assembly urges the Secretary General to
include th El Nin~o Southern Oscillation (ENSO, or most commonly known as « El
Nin~o ») phenomenom and its consequences in the ongoing activities of IDNDR to
improve the effectiveness and increase international coordination of
early-warning systems with regard to natural and similar disasters (see

81.   In line with the resolution on « International cooperation to reduce the
Impact of the El Nin~o phenomenom » adopted by the General Assembly on 
(date?), at its fifty second session (A/52/... (A/C.2/52/L.37), it is
recommended that the Commission on Sustainable Development :

      (i)  Encourages and supports the elaboration and implementation
      of national, regional and international projects aiming at
      reducing and preparing the impacts of disasters on water
      resources and water supply systems. Such projetcs could be part
      of an existing, or the starting point of new Natural Disaster
      Reduction and Prevention programme.
      (ii)  Encourages the research activity on climate and its impacts
      in the context of natural disasters. Moreover, existing
      scientific knowledge should be applied and technology should be
      used to better :

      - control human occupancy of flood-prone lands;
      - plan drought mitigation measures, in particular adequate land-
use management.

82.   In this vein, climate information and prediction services, including the
frequency and intensity of past storms, data on air humidity, precipitation,
evaporation, runoff, river or reservoir gauges, could be used and developed
for water management and disaster reduction. WMO has responsibility at the
intergovernmental level for coordinating and supporting action by Member
States to collect and distribute the meteorological and hydrological data and
information that are needed to forecast water-related disasters and mitigate
their effects. This involves the World Weather Watch, the Hydrology and Water
Resources Programme of the Organization and the Climate Information and
Prediction Services (CLIPS) project which aim is to provide the various users
(decision makers, policy makers) with a package of relevant climate
information and prediction services. Such tools are developed from statistics
based on observation, real-time satellite observation and numerical models
results. The implementation of integrated information management systems and
real-time data observation and reporting systems, could provide the elements
to build and organize disaster prevention. 

83.   The Commission on Sustainable Development is therefore invited to:

      (i)   Support and encourage coordinated efforts among regional,
      national and international players in the use and development of
      modern climate information and prediction services.

      (ii)   Support and encourage the transfer of technology and
      capacity building necessary to the development of such services,
      particularly in developing countries;

      (iii)  Encourage international exchange of hydrological and
      meteorological data for conducting studies and support projects
      aiming to:

      - develop forecasts of flow and extreme hydrological regime in basins
        with joint use of water resources;
      - detect and prevent disasters due to insufficient water or
        temporary lack of water.

84.   In order to reduce the vulnerability faced with extreme
hydro-meteorological events, it is also recommended that the Commission on
Sustainable Development:

      (i)  Support and encourage Governments to apply such climate
      services to:

      - adopt a loss-minimization strategy for flood management,
        including structural and non-structural measures such as flood-
        proofing structures, flood insurance, flood warning systems,
        evacuation and restoration plans.

      - base redevelopment programmes following flood disasters on
        risk-minimization land-use controls and management strategies.
        Public investments, subsidies and incentives on private
        investment for redevelopment, should be in accord with such

      - plan drought mitigation measures based on specific rules for
        reducing water withdrawals. Efficient and equitable sharing of
        limited resources, through pooling of available supplies,
        allocations of use in line with the greatest social value, with
        appropriate compensation for losers may thus be achieved.

      - preventing and mitigating damages to water supply and sewage
        systems. By reducing the vulnerability of water supply systems
        to natural hazards, the population is less exposed to water
        borne disease risks.

      (ii)  Encourages Governments to develop policies, regulations and
      controls to reduce risks of water pollution due to the effects of
      natural disasters on the production and/or use of dangerous
      chemicals and toxic materials.

85.   Such measures are also relevant to other international programmes,

      - the United Nations Convention to Combat Desertification which
        was adopted by 108 parties in June 1994 and entered in force in
        December 1996;
      - the United Nations Centre for Human Settlements (« Habitat »).
        Its outcome, the Habitat Agenda (Habitat II ; Istanbul, June
        1996), reflects the priority issues to be addressed, such as
        natural disasters, availability of freshwater, environmental
        pollution and climate change.

86.   Since many United Nations Agencies are involved in these programmes and
in others, also relevant to water management and freshwater supply, it is
recommended that the Commission on Sustainable Development:

      (i)  Call on Member States to support the efforts undertaken in
      those programmes in order to achieve loss reduction as soon as
      possible, through close collaboration and concerted action at all

      - at an international level, between United Nations Agencies;
      - between nations themselves, especially between developed and
        developing countries, and between countries sharing the same
        water resources, the same risks, and the same goals, i.e. to
        reduce vulnerability to natural disasters ;
      - at a national level, between Ministries concerned with any
        aspect of water management as well as with natural disaster
        reduction ;
      - at an individual level between decision makers, policy makers,
        scientists and users.

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Date last posted: 8 December 1999 15:15:30
Comments and suggestions: DESA/DSD