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Rainwater cisterns: traditional technologies for the dry areas

Authors:
  • International Center for Agricultural Research in the Dry Areas (ICARDA), Amman, Jordan & Tottori University, Tottori, Japan
Rainwater Cisterns
Traditional technologies for dry areas
Akhtar Ali, Theib Oweis,
Abdul Bari Salkini and Sobhi El-Naggar
International Center for Agricultural Research in the Dry AreasInternational Center for Agricultural Research in the Dry Areas
P.O. Box 5466, Aleppo, Syria
About ICARDA and the CGIAR
Established in 1977, the International Center for Agricultural
Research in the Dry Areas (ICARDA) is one of 15 centers
supported by the CGIAR. ICARDA’s mission is to contribute
to the improvement of livelihoods of the resource-poor in dry
areas by enhancing food security and alleviating poverty
through research and partnerships to achieve sustainable
increases in agricultural productivity and income, while ensuring
the efcient and more equitable use and conservation of natural resources.
ICARDA has a global mandate for the improvement of barley, lentil
and faba bean, and serves the non-tropical dry areas for the improvement
of on-farm water use efciency, rangeland and small-ruminant production.
In the Central and West Asia and North Africa (CWANA) region, ICARDA
contributes to the improvement of bread and durum wheats, kabuli chickpea,
pasture and forage legumes, and associated farming systems. It also works on
improved land management, diversication of production systems, and value-
added crop and livestock products. Social, economic and policy research is
an integral component of ICARDA’s research to better target poverty and to
enhance the uptake and maximize impact of research outputs.
The Consultative Group on International Agricultural Research
(CGIAR) is a strategic alliance of countries, international and
regional organizations, and private foundations supporting
15 international agricultural Centers that work with national
agricultural research systems and civil society organizations
including the private sector. The alliance mobilizes agricultural
science to reduce poverty, foster human well being, promote
agricultural growth and protect the environment. The CGIAR generates global
public goods that are available to all.
The World Bank, the Food and Agriculture Organization of the United
Nations (FAO), the United Nations Development Programme (UNDP), and
the International Fund for Agricultural Development (IFAD) are cosponsors
of the CGIAR. The World Bank provides the CGIAR with a System Ofce in
Washington, DC. A Science Council, with its Secretariat at FAO in Rome, assists
the System in the development of its research program.
Rainwater Cisterns
Traditional technologies for dry areas
Akhtar Ali, Theib Oweis,
Abdul Bari Salkini and Sobhi El-Naggar
International Center for Agricultural Research in the Dry Areas
Rainwater Cisterns
II
Copyright © 2009 ICARDA (International Center for Agricultural Research in the Dry
Areas)
All rights reserved.
ICARDA encourages fair use of this material for non-commercial purposes, with proper
citation.
Citation: Akhtar Ali A, Oweis T, Salkini AB and El-Naggar S. 2009. Rainwater cisterns:
traditional technologies for dry areas. ICARDA, Aleppo, Syria. iv + 20 pp.
ISBN: 92-9127-223-X
About the authors
Akhtar Ali, Former Water and Soil Engineer, ICARDA.
Theib Oweis, Director, Integrated Water and Land Management Program, ICARDA,
Aleppo, Syria. E-mail t.oweis@cgiar.org
Abdul Bari Salkini, Former Agricultural Economist, ICARDA.
Sobhi El-Naggar, Project Director, European / Egyptian Financial Investment and
Sector Cooperation – Rural Component, Giza, Egypt.
International Center for Agricultural Research in the Dry Areas (ICARDA)
P.O. Box 5466, Aleppo, Syria.
Tel: (963-21) 2213433
Fax: (963-21) 2213490
E-mail: ICARDA@cgiar.org
Website: www.icarda.org
The views expressed are those of the authors, and not necessarily those of ICARDA.
Where trade names are used, it does not imply endorsement of, or discrimination
against, any product by the Center. Maps have been used to support research data,
and are not intended to show political boundaries.
Traditional technologies for dry areas III
Contents
Background ............................................................................................................. 1
Water scarcity in the dry areas ...........................................................................1
Why harvest rainwater? .......................................................................................1
The literature on water cisterns............................................................................2
Rainwater Harvesting and Utilization .....................................................................3
What is rainwater harvesting? .............................................................................3
Why is it critical in dry areas? ...............................................................................3
How to harvest rainwater? ...................................................................................4
Who should plan and pay for rainwater harvesting? .......................................6
Cisterns and Rainwater Harvesting ........................................................................7
History of cisterns ...................................................................................................7
Types of cisterns and their main components ...................................................7
Construction costs ................................................................................................8
Water use and management .............................................................................8
Planning and Development of Cisterns ............................................................... 10
Socioeconomic considerations ........................................................................10
Estimating water demand .................................................................................10
Location and storage capacity ........................................................................10
Rainfall and runoff ...............................................................................................11
The catchment area ..........................................................................................11
Environmental aspects .......................................................................................12
Construction of cisterns ......................................................................................13
Operation and maintenance ...........................................................................15
Common damage to cisterns ...........................................................................15
Sedimentation in cisterns ...................................................................................16
Maintaining water quality ..................................................................................16
Improving Cistern Efciency.................................................................................17
Improving water collection efciency .............................................................17
Increasing water storage efciency .................................................................17
Determining the multiple lling potential of a cistern .....................................18
Cistern water for agriculture ..............................................................................18
Conclusions and Recommendations .................................................................. 20
References ............................................................................................................. 20
Traditional technologies for dry areas 1
Water scarcity in the dry areas
During the past century the world’s popula-
tion has tripled, and water consumption has
increased six-fold. This has put severe pressure on
water resources worldwide, and particularly in ar-
eas where rainfall is already scarce. Of the global
freshwater supplies of 40,700 km3, only 12,500 km3
are accessible: 9000 km3 as stable river ows and
3500 km3 in reservoirs (Gleick 1993). With world
population at over six billion, available freshwater
is about 2000 m3 per capita per year. The popula-
tion is expected to reach 10 billion by the year
2050, which would reduce water availability to
1250 m3 per capita per year, barely above the
‘scarcity’ level of 1000 m3.
While water is a global issue, the critical factors
limiting its availability are not global, but rather
regional, national and local issues. This is because
in many cases water shortages are due to two
factors, often acting in combination:
Adequate water is not available at the loca-
tion of use
User communities lack the capacity to cap-
ture and store the available water.
Drylands cover over 40% of global area and are
home to about 700 million people (Parr and Stew-
art 1990). Water scarcity is a common feature of
dry areas, and directly affects food production
and livelihoods in rural areas. In the Middle East
and North Africa, for example, 15 of 19 countries
are below or near the water scarcity level. Nine
countries have less than 250 m3 per capita per
year, three others have 250-500 m3 (Gleick 2000).
Low and erratic rainfall, limited groundwater, and
high evaporation rates are the main causes of
water scarcity in these areas.
With the exception of major river basins, inhabit-
ants of dry areas have continually struggled to
cope with water shortages. The problems are be-
coming more severe. For example, in northwest
Egypt, water is transported by rail for hundreds of
kilometers to supply dwellings along the coast. In
Jordan, public water supply is limited to twice a
week; people buy water from private suppliers for
US$ 1-2 per cubic meter in summer. In mountain-
ous areas in Yemen and Pakistan, women spend
3-6 hours per day transporting water for house-
hold requirements. Across Africa, one study esti-
mated that 46% of the population lacked access
to safe drinking water and 34% lacked adequate
water for sanitation (Gleick 1998).
Why harvest rainwater?
Rainwater harvesting can help meet basic water
requirements and reduce water shortages. Rain-
fall is outside the farmer’s control, but a reason-
able amount of runoff can be captured even
from low rainfall by suitably modifying the catch-
ment area. Capture and storage of this precious
rainwater allows it to be used productively. Water
availability depends not only on the amount,
but also on the pattern of rainfall. Intense storms
generate high runoff, which is lost quickly with
little on- or off-site use. In India, where some areas
have an average annual rainfall of over 1000
mm, most rainwater ows away quickly, leading
to water shortages.
Background
This 2000-year old cistern in Syria is still in use.
Rainwater Cisterns
2
The literature on water cisterns
Rainwater cisterns are indigenous underground
water storage structures, widely used in the Ma-
trouh area in northwestern Egypt, in steppe areas
in Syria and Jordan, and elsewhere. Little informa-
tion is available on the design, construction and
operation of traditional cisterns. Most available
publications on water cisterns deal with rooftop
water harvesting, using pre-fabricated materials.
These cisterns are of very limited capacity (a few
cubic meters) and are more expensive than un-
derground cisterns. Most publications on rainwa-
ter harvesting are written for water professionals
and researchers, not for local users and develop-
ment practitioners.
This publication responds to the needs expressed
by water users, and especially by ICARDA’s
research and development partners. It will also
be useful to policy makers responsible for water
development in dry areas. Building on research
in dry areas in Egypt and elsewhere, it provides
information on rainwater harvesting, the design
and construction of cisterns, and improvement
of existing systems, covering traditional methods
as well as modern innovations. We try to explain
concepts as well as practical issues without using
technical terms that need detailed knowledge
of the subject. Background information about
northwest Egypt is presented in order to better
explain the context, and help readers apply the
techniques explained, to other areas with similar
conditions.
Traditional technologies for dry areas 3
What is rainwater harvesting?
Whenever rain falls over an area, part of it is
intercepted and inltrates into the soil. Excess
rainfall ows away downwards, from higher to
lower elevations, in the form of a ‘sheet’ or as a
concentrated ow. Collection, storage and utili-
zation of this running water is known as rainwater
harvesting.
The term ‘rainwater harvesting’ is derived from
the more general ‘water harvesting’ (Pacey and
Cullis 1999), which has a number of denitions.
Critchley and Siegert (1991) dened water har-
vesting as ‘collection of runoff for its productive
use’. Oweis et al. (1999) dened it as ‘the pro-
cess of concentrating rainfall runoff from a larger
drainage area (source) to a smaller productive
area (target)’. Figure 1 illustrates the concept.
Depending on the catchment characteristics,
small areas can produce runoff between 20 and
80% of the rainfall received. Generally, for a given
amount of rain, the smaller the area, the greater
the runoff efciency (runoff per unit area). At
watershed or basin scales, high abstraction losses
may result in low runoff efciencies, less than 5%.
Therefore, it is best to harvest rainwater at or near
the source, particularly in dry environments.
Why is it critical in dry areas?
Water is a basic requirement for life, livelihoods,
and economic development. In many areas, rain
is the only source of freshwater for drinking and
domestic use, so rainwater harvesting is critical.
Water harvesting can help improve local water
supplies in any area. It is particularly important in
dry areas, for several reasons.
Population growth and economic develop-
ment have created imbalances in water
availability and demand. Rainwater harvest-
ing can alleviate water shortages at local
level, and improve equity and reduce social
injustice within communities, and between
different communities that share a water
source
Drylands are fragile environments. Over-
exploitation and mismanagement of water
resources, and erosion caused by uncon-
trolled runoff, can cause irreversible damage.
Rainwater harvesting can help solve both
problems
Rangelands in dry areas often do not have
sufcient water for animals to drink, so grazing
opportunities are lost. For example in range-
lands in Syria and Jordan, livestock herd-
ers use trucks to transport animals from one
Rainwater Harvesting and Utilization
Figure 1. Schematic representation of a typical
rainwater harvesting system. In many dry areas, harvested rainwater in wells is the
only source of freshwater.
Rainwater Cisterns
4
place to another for better grazing; however,
lack of water restricts the use of many oth-
erwise potentially suitable areas. Rainwater
harvesting in these areas could make grazing
feasible.
The benets of rainwater harvesting are well
documented. They include improving the veg-
etation (Perrier 1990, Boers 1994, Oweis et al.
2001); arresting the degradation of soil and water
quality; and reducing the substantial time and
energy spent (by rural women) in fetching water
from long distances.
Pacey and Cullis (1999) identify three ‘target’ ar-
eas where rainwater harvesting could realistically
have a major impact:
Arid and semi-arid areas, where pastoralism is
the main livelihood, and fruit trees support a
small portion of the population
Tropical regions with steep topography,
where runoff generates and dissipates quickly
Isolated islands, where rain is the only source
of freshwater.
How to harvest rainwater?
Water harvesting methods vary, depending on
local conditions (see photos below). Depressions
in the ground are a natural way of water har-
vesting. Coarse streambeds may harvest runoff
to supplement sub-surface ows or recharge
groundwater. Most human-introduced methods
are purpose-driven. For example, rooftop water
harvesting helps to supplement domestic water
supplies, or to irrigate parks and gardens. Cross-
ow dikes harvest runoff to improve soil moisture
storage immediately upstream, to support crops
and orchards. Diversion structures across streams
divert ow to elds or other watercourses. Water
storage in ponds and reservoirs can serve many
purposes including municipal supply, irrigation,
and livestock watering. Cisterns in the Middle East
and North Africa are used largely for domestic
use and for watering livestock.
There are many ways to classify different water
harvesting methods. Oweis et al. (2001) divided
them based on micro- and macro-catchments,
Pacey and Cullis (1999) on source of water
and purpose of rainwater harvesting. Critchley
and Siegert (1991) classied them as micro-
catchments, external catchment systems, and
oodwater farming. Table 1 categorizes different
rainwater harvesting systems based on type of
structure, function, and characteristics of the im-
mediate environment.
Nomadic pastoralists face major problems in
transporting water. Rainwater harvesting is cheaper,
more practical, and more sustainable.
Negarim, a small runoff basin, typically used to
harvest water for fruit trees.
Traditional technologies for dry areas 5
Table 1. Different rainwater harvesting systems.
Type of structure Main function Characteristics of suitable location
Rainwater cisterns Store water from a catchment area
ranging from hundreds to thousands
of square meters
Stable catchment, preferably rocky, with
3-15% slope and soft bedrock for digging
Rooftop water harvesting Collect water from rooftop through
conduits via gravity ow, store in
tank
Adequate roof area (several hundred sq
meters) with stable surface material
Hillside conduits and tanks Water from hillside ows through
conduit into tanks, ponds, or directly
to elds
Stable hillslope, very low soil erosion, water to
be used nearby
Cross-ow dikes Intercept sheet ows, increase ow
residence time, improve inltration
and soil moisture storage
Land slope 3-8%, adequate soil depth
(preferably > 1 m) to store moisture. Crops
that will use stored soil moisture
Cross-stream dikes Capture concentrated stream ows,
store as soil-moisture for fruit trees or
crops
Wadis of slope < 7%, soil depth > 1 m,
preferably 2 m. Stable wadi sides. Suitable
spillover structures for disposal of surplus ows
Surface reservoirs Multi-purpose water storage Suitable topography and geology for
reservoir. Stable sides for dam and spillway
construction. Adequate catchment area, a
few sq km depending on water requirements
Sub-surface dams Underground storage Sand bed with shallow rock (2-3 m from bed).
Stable, narrow section to build dam
Continuous contour ridges
or Intermittent contour
bunds
Improve sheet ow inltration and
soil-moisture. Suitable for forage
shrubs, drought tolerant fruit trees,
and crops
Slope 3-6%. Catchment 10-15 m wide, with
low inltration rate
Runoff strips Stabilize yield of eld crops Slope 3-6%. Catchment 10-15 m wide, with
low inltration rate
Terraces Increase run-on residence time and
inltration, improve soil moisture Moderate hillslopes or undulating areas with
adequate soil depth for crops
Rooftop water
harvesting in
Ethiopia (left)
and Brazil (right).
Rainwater Cisterns
6
Who should plan and pay for
rainwater harvesting?
Technical issues are important in the design of
water harvesting structures. But socioeconomic is-
sues such as who should harvest and who should
pay, are as important – and sometimes even
more important – than the technical aspects. We
divide rainwater harvesting systems into two main
classes:
Rainwater harvesting that does not have
signicant off-site impacts. With a few excep-
tions, this type of harvesting does not require
large investments. Individuals or a small group
of beneciaries can afford the cost.
Rainwater harvesting that could have signi-
cant off-site or downstream impacts. This type
generally requires much larger investments,
beyond the capacity of individuals or small
groups.
In the rst category, the beneciaries will be a
group of individuals, so it is often expected that
the beneciaries should (or will) make the neces-
sary investment. However, most users of rainwater
harvesting are the rural poor, who may not have
adequate capital. In these cases, governments
should provide credit or make other arrange-
ments to enable people to make the relatively
small investments needed. The second category
is more critical, since the development of rain-
water harvesting systems at one location may
benet or disadvantage people or infrastruc-
ture downstream or elsewhere. In these cases,
thorough impact assessment is a prerequisite.
For example, construction of wadi dikes at one
location may reduce the destructive capacity of
water owing downstream or reduce sediment
deposition downstream. This might reduce the
damage to downstream infrastructure such as
reservoirs, culverts and transmission lines. In this
case, society, being a beneciary, should also
pay part of the investment costs. Other down-
stream benets will also benet society at large:
reduction in land degradation, improvement of
water quality. On the other hand, water harvest-
ing could sometimes reduce the water supply,
or even create water shortages, at downstream
locations – leading to questionable benets and
potential conicts.
Traditional technologies for dry areas 7
A cistern is a sub-surface water collection and
storage structure, generally dug at the lowest
level of a small catchment. To be effective, a
cistern should have an adequate catchment to
generate runoff under whatever rainfall condi-
tions are expected, a suitable underlying geologi-
cal formation, and should make efcient use of
stored water. The rst runoff from the catchment
is usually diverted away; only the subsequent
(cleaner) ow is allowed to enter the cistern. A
ditch disposes of the surplus water at downstream
through an outlet. The water from the cistern is
extracted manually by bucket or hand pump.
This water is used mainly for domestic and animal
needs. It could also be used for supplemental
irrigation of crops or trees if sufcient water is
available.
Although cisterns may not be able to meet the
total water demand of a rural community, they
can play a signicant role. These low-cost struc-
tures are affordable for poorer households, and a
safe, convenient way to store water for later use.
Cisterns are also convenient for irrigating small
pieces of land at varying altitudes (Liu 2000).
History of cisterns
Cisterns can be traced back to before 3000 BC –
and even earlier, when natural caves were used
to store water long before man-made cisterns
(Wahlin 1997). The oldest recorded house-cisterns
were built in Palestine before 3000 BC Wahlin
(1997) quoted an archeology encyclopedia:
The rst cistern was dug in the Middle and Late
Bronze Age, about 2200 to 1200 BC. The rainwa-
ter that was collected in them during the short
rainy season would be enough for at least one
dry season. In some parts of Palestine cisterns
were the main (sometimes even the only) source
of drinking water. In the early Iron Age (1200–1000
BC) the sides of the cisterns began to be cov-
ered with watertight plaster, which considerably
prolonged the time for which water could be
stored. It was this important innovation that made
it possible to extend the areas of settlement into
the mountainous part of the country.
Dug-in and stone-lined cisterns in loess soil were
built in Negev during the Iron Age. Rock-cut
cisterns date back to the Nabatean era around
two millennia ago. The intensive use of cisterns as
water storage structures has varied with location
and time. For example, the intensity of cistern
building increased in northern Jordan during
1100-1516 AD (Lenzen et al. 1985). There are nu-
merous old and new cisterns in the Syrian steppe
and parts of Libya, Tunisia and Palestine. Most of
these cisterns are a water source for nomads and
their livestock.
Around 300 BC the Romans began constructing
cisterns in northwest Egypt to harvest rainwater
for domestic use and livestock watering (MRMP
1992). The storage capacity of these cisterns was
500-1500 m3, the smallest for domestic use and
the largest for livestock. Cisterns were typically
built in a rocky area of moderate hillslopes. After
the Roman era, people continued to dig cisterns.
Currently, most cisterns are constructed in sizes
ranging from < 50 m3 in Jordan to about 300 m3 in
northwest Egypt.
Types of cisterns and their main
components
Two types of cisterns are common: single-cell and
multi-cell. The choice of single or multiple cells
depends on the rock and soil characteristics and
the storage requirement. Cisterns of larger ca-
Cisterns and Rainwater Harvesting
Roman cistern (1st to 3rd century AD) excavated at
ICARDA’s research station in Tel Hadya, Syria.
Rainwater Cisterns
8
pacity (> 300 m3) generally have more than one
cell, while single-cell cisterns are smaller, usually
built where soil and rock conditions do not allow
for large capacity.
A cistern has three main components: an inlet
including a settling basin, a shaft (mouth and
neck), and a storage chamber. The inlet allows
runoff to enter the storage chamber, while the
outlet allows excess water to ow out. The mouth
opening facilitates withdrawal of water from the
cistern, and is 50-75 cm in diameter. A wooden or
steel grate covers the opening to prevent the en-
try of contaminants. The chamber is excavated
in soft to medium soils underneath a layer of hard
sedimentary rock, 50 cm to 2 meters thick, which
forms a natural ceiling to the chamber. The inner
sides of the chamber are plastered to minimize
leakage. The chamber requires cleaning every
four to ve years if proper sediment traps are not
provided. Generally, water is extracted from the
cistern using buckets, although windmills, hand
pumps and diesel pumps are also used. A typical
cistern is shown in Fig. 2.
The shape and size of cisterns vary from one
place to another. Old Roman cisterns can be as
large as 1500 m3 (the larger ones were multiple-
cell cisterns with sub-surface side trenches).
Cisterns built in recent years are usually 100-
300 m3 capacity. The common chamber shapes
are circular, elliptical and rectangular (Fig. 3).
Construction costs
The cost of cistern construction generally de-
pends on the rock type, availability of skilled
labor, and location of the proposed cistern. The
major cost items are digging, plastering, the inlet,
and the cover. Labor constitutes by far the major
cost. A household survey in northwest Egypt and
cost estimates by the Matrouh Resource Man-
agement Project (MRMP) showed that the cost
varied between US$ 7 and US$ 15 per cubic me-
ter of storage capacity.
Water use and management
There is no binding rule for the use of cistern
water. Generally, drinking and household needs
take top priority, followed by animal watering,
and then supplemental irrigation. An MRMP farm
survey (unpublished data) showed that about
20% of households use cistern water only for hu-
man consumption, 40% for people and livestock,
5% for people and trees, and 35% for all three
uses. There was one cistern per household on
average; but variability was high: over 25% of the
population did not have a cistern, 52% had one,
16% had two, 6% had three or four, and 1% had
more than four (the maximum was eight cisterns).
Generally, a family depends on its own cistern for
water, but there are no restrictions on the use of
Figure. 2. Components of a typical single-cell cistern. Figure 3. Some common cistern storage chambers.
Traditional technologies for dry areas 9
cistern water. Even passers-by may use it for drink-
ing or for watering livestock. Small basins near
the cistern serve for animal watering; sometimes
water transportation may be required. Bedouin
communities are the largest users, and have a
long history of using cistern water, and the deci-
sion criteria and constraints to management are
well known. Traditional communal practices for
cistern management generally work well, but
increasing demand has raised new issues. Cistern
management follows some broad principles:
Cisterns for domestic use and animals are
separated from those for agriculture
All members of the family have equal rights
to water. In case of severe drought, cistern
water is used only for domestic purposes;
animals are sent to other areas where water is
available
The family makes joint decisions and the head
of the family is responsible for implementation
Maintenance expenses such as de-silting are
met by contributions from users at the time of
the operation. Cisterns are generally owned by a family, but non-
owners are permitted free access in most cases.
Rainwater Cisterns
10
Socioeconomic considerations
Since each cistern typically belongs to one fam-
ily, community issues generally do not affect
decisions on building or use of cisterns. Neverthe-
less, analysis of socioeconomic conditions and
the participation of beneciaries early in cistern
development could signicantly improve cistern
performance. When planning for a new cistern,
four factors are important:
Land ownership and its suitability for cistern
construction. For example, if the cistern owner
does not own or control the entire catch-
ment, this could later create social problems.
Ownership-related issues should be resolved
at the planning stage
Cisterns for domestic purposes should be
located in or close to the house(s) where the
users live. Cisterns based on rooftop or court-
yard water harvesting are best. Cisterns for
agricultural use should be located as close as
possible to farms
Appropriate topography and soil/rock condi-
tions may not be available everywhere. On
the other hand, the owners of a suitable loca-
tion may not have the capital to construct a
cistern
• Upstream–downstream conicts may be seri-
ous if a large amount of water is collected
and downstream users are affected. Studies
of previous inter- and intra-tribe conicts and
their management could help minimize future
conicts.
Estimating water demand
Most cistern users use the water very conser-
vatively, although there are some exceptions.
Based on experience in marginal dryland envi-
ronments in the region, the demands for cistern
water per day are:
Human consumption including drinking, sani-
tary and other uses: 50 liters per person
Sheep and goats: 5 liters per head
Camels: 15 liters per head.
Water demand for supplemental irrigation varies
greatly and is limited by local water availability
and storage capacity. As a rule of thumb, com-
pute the household’s total water demand based
on the above criteria, and add 30% to meet wa-
ter requirements for the family’s home vegetable
garden.
Location and storage capacity
Site selection for a cistern should satisfy four main
conditions:
Adequate rainfall, preferably 200 mm per
year with 4-5 runoff events
A stable catchment area
• Suitable soils/rock
• Easy access.
Rainfall and catchment characteristics dictate
the size of catchment needed. The most suitable
geological formation for the construction of a
rainwater cistern is a good quality, fault-free, 1-2
m thick rock, over 4-5 m deep soft soils. The rock
acts as a roof for the chamber, which is formed
by excavating the soil. Rock type and thickness
determine the cistern dimensions. A rapid assess-
ment with the users and/or community can be
helpful in decision making.
Planning and Development of Cisterns
Large numbers of cisterns have been built in the
Matrouh region in the past decade, improving
local water availability, but also affecting supplies
downstream.
Traditional technologies for dry areas 11
The top limestone layer determines the width,
while the underlying soil determines the depth
of a cistern (Fig. 4). Data for about 100 recently
constructed cisterns in northwest Egypt showed a
maximum cistern width of approximately 2.5 m for
50 cm rock thickness, 4 m width for 1m rock, and
5 m width for 2 m rock. There were large varia-
tions in dimensions, probably due to rock quality
and safety factors, so no denite conclusions can
be drawn. Nevertheless, excavating trenches of
shorter spans and longer sections can increase
cistern capacity. Once a safe width is deter-
mined, the length can be increased depending
on storage requirement. Impermeable or water-
tight soils are largely suitable, while a crack-free
and sufciently thick plaster layer is required
to avoid seepage from the storage chamber.
Indigenous knowledge is vital and should be used
wherever available. The design may be reviewed
during construction when information on the sub-
soil strata and rock is available.
Rainfall and runoff
The amount of runoff depends on two factors:
amount of rainfall and characteristics of the
catchment area. As an approximation, 100 mm
annual rainfall over a steppe type catchment
area with 30% bare rock and 3-5% slope could
generate 10-12 mm of runoff. To achieve good
design, a hydrological assessment should be
done, analyzing rainfall data to estimate the
average number of runoff-generating events per
year, the rainfall threshold value to initiate runoff,
and the expected runoff patterns and amounts.
Because rainfall is highly variable (Fig. 5), it is best
to use a conservative design, to minimize the risk
of inadequate water collection.
To estimate runoff patterns, it is desirable to col-
lect data under local conditions, and thus de-
velop rainfall–runoff relations under various sets
of conditions. However, if data are not available,
empirical tools and experience can substitute.
The runoff coefcient K, is runoff expressed as a
percentage of rainfall (i.e. runoff/rain 100). It is
location- and event-specic and should be ap-
plied to other environments with caution (Critch-
ley and Siegert 1991). At Saloofa near Matrouh,
average K values were 12-20% (MRMP, unpub-
lished data).
The catchment area
The catchment area collects runoff and directs it
to the cistern. The cistern capacity will depend on
the quantity of runoff, which in turn depends on
catchment size, rainfall, land slope and soil types.
Figure 4. Schematic diagram of rock and soil
formations in northwestern Egypt.
Figure 5. Annual rainfall at Matrouh, northwestern Egypt, 1944–1992.
Rainwater Cisterns
12
Factors affecting the catchment area
Topography and terrain prole (land slope,
drainage density and other micro-topographic
features) play an important role in runoff genera-
tion and transmission to the cistern inlet. Steep
topography reduces the time of concentration
and the inltration rate, resulting in higher runoff.
Flat or undulating topography with depressions
or other ow-retarding obstacles such as stones,
dikes or logs, reduces ow velocity, increases ow
time and inltration, and thus reduces the runoff.
A boundary ridge and/or ditch can help direct
sheet ow to the cistern. In loose-textured soil,
inltration is higher, therefore runoff is low. In com-
pacted soils or rock, inltration is low and runoff
is high. Runoff is also high in soils with a surface
crust.
A vegetation-free area generates more runoff
than an area covered with vegetation. Veg-
etation cover retards the ow and encourages
inltration, thus reducing runoff production. But
steep, vegetation-free relief could cause exces-
sive soil erosion, leading to poor water quality
and high management cost of the cistern. It is
necessary to achieve a good balance between
suitable topography, soil quality and vegetative
cover while choosing an optimum catchment
area in terms of runoff production.
Catchment area of existing cisterns
A well-designed cistern will have adequate
catchment area to ll the cistern more than once
a year. A survey of existing cisterns in the region
showed that the catchment area is usually a few
thousand square meters, with an average slope
of 2-6%, and sparse or negligible vegetation. Bare
rock and/or compacted soils generally domi-
nate catchments; these characteristics gener-
ate maximum runoff even in low-rainfall areas.
Inadequate catchment sizes fail to generate the
required amount of runoff. If the catchment area
cannot be increased, runoff can be increased by
treating the catchment area. This can be done
in various ways: clearing vegetation, surface
smoothing, removing obstructions (loose stones,
debris and logs), surface compaction, or using
synthetic or biological materials to seal the soil
surface. For example, potentially high inltration
spots can be treated with sealant, polythene
sheet or geo-membrane to reduce inltration
and increase water yield.
Table 2 shows a hypothetical estimation of catch-
ment size needed to ll a 100-m3 cistern once a
year under various rainfall conditions. It assumes
a runoff coefcient of 20% and is based on a 50-
year rainfall record.
Environmental aspects
Water quality is a major concern when cisterns
are used. Cistern water can be contaminated
during runoff over the catchment, or during and
after storage. The main pollutants can include
eroded soil, organic matter, human and animal
waste, dissolved salts and fuel oil. Stored water
can also become contaminated by exposure to
the atmosphere and during water lifting and/or
pumping. Selecting a suitable catchment area
and keeping it free of pollutants is the best way
to maintain water quality. It is essential to mini-
mize soil erosion by preventing soil disturbance
and providing a sediment trap at the cistern en-
try. The traditional practice of diverting away the
rst storm runoff is effective in reducing contami-
nation.
The downstream consequences of rainwater
harvesting may not be serious since the amount
stored in a cistern is relatively small. However,
construction of many structures in a small area
could markedly reduce downstream ows, and
this should be considered during planning. A
decision matrix can assist preliminary planning
decisions (Table 3).
Rocky catchments ensure high runoff and better
water quality; while the area needed is minimized.
Traditional technologies for dry areas 13
Construction of cisterns
Ground preparation
The rst step in cistern construction is to remove
the overburden (loose or soft soil over a hard rock
layer) to expose the rock layer. This is done either
manually with hand tools or with construction
machinery (such as a grader or blade-equipped
tractor), provided the machine operation does
not damage the rock. Removal of overburden al-
lows access to sound rock and provides informa-
tion on the extent of the rock layer. The overbur-
den should be dumped in a safe place, away
from the main structure.
Rock puncturing and development of cistern
mouth
Development of the cistern mouth requires care-
ful puncturing of the rock layer. Damage to the
rock during puncturing can be detrimental to
the cistern structure. First, heat the rock surface
where puncturing is required. Then excavate the
hot surface with hammer and chisel so that the
rock is not fractured. Depending on the rock type
and depth, heating might be required more than
once. Bore through the rock slowly and carefully
to create a hole through it, and then widen the
hole to the required mouth size (50-75 cm diam-
eter). The depth and quality of rock is assessed
at this time, to aid cistern design. The mouth
provides access for excavation of the soil un-
derneath. After construction, it is used to extract
water from the cistern. Rock boring is a very time-
consuming process and requires skilled labor. Ma-
chine drilling is a much faster method, but should
be used only if it does not damage the rock.
Development of storage chamber
Rock thickness and extent dictate the cistern
dimensions, shape and capacity. A bell-shaped
cistern of 100-300 m3 capacity can be accom-
modated under sound rock about 1 m thick.
Roman cisterns of larger capacities (1000-1500
m3) consisted of multiple cells with alternate side
trenches (Fig. 3). Excavation of the chamber
requires manual work, because the use of ma-
chinery is restricted due to the small opening and
exposed rock, and because the movement of
heavy machines over or near the cistern can se-
verely damage it. Excavated material is removed
by a bucket and rope at shallow depths, and a
pulley and bucket at greater depths. Dump the
excavated material away from the cistern so
that it does not add extra load to the rock cover.
Beyond the mouth opening, carefully enlarge
the excavation under the rock. Avoid over-exca-
vation as it may cause the sides to collapse and
endanger workers. Finally, ll in the cracks and
plaster the chamber to prevent seepage.
Table 2. Catchment size needed to ll a 100 m3 cistern under different rainfall regimes.
Rainfall (mm/year) Catchment size needed (m2) No. of years rainfall
exceeds 50-year average Chances of lling the cistern
once a year
50 10,000 48 96%
100 5000 33 66%
150 3333 20 40%
200 2500 13 26%
250 2000 3 6%
Calculation based on 50 – year rainfall data
Table 3. Decision matrix for planning of a cistern (assuming geology is suitable).
Small catchment area Large catchment area
Low rainfall Low runoff production potential. Small
cisterns can be developed. Need to improve
catchment area
Rainfall is the limiting factor for runoff
production. Increase catchment to
increase runoff
High rainfall Catchment area is the limiting factor. Select
cistern size depending on available catchment Ideal situation. Large cisterns can
be built if topography and rock/soil
conditions permit
Rainwater Cisterns
14
Building the superstructure
The above-ground part of a cistern is known as
the superstructure. It may include the inlet and
outlet, mouth and sand trap. The inlet is an open-
ing of 30-40 cm diameter at the ow route to
guide water to the cistern. A recess on the op-
posite side of the inlet serves as an outlet to safely
remove surplus ows to a downstream ditch. Steel
gratings on the inlet and outlet prevent the entry
of logs or other large contaminants. A masonry
or concrete wall 50-75 cm high, generally round
in shape, serves as the cistern mouth, which is
covered with a hinged steel or wooden cover. A
sand trap of about 1 m × 1 m × 1 m prevents sedi-
ments from entering through the inlet.
Treatment of catchment area
Improvements to the cistern catchment area
can induce runoff and increase runoff efciency.
The improvements are made by (i) clearing the
catchment of stones or debris, grading uneven
parts, and improving the approach conditions, (ii)
constructing a ditch along the lower parts of the
catchment boundary to guide ow to the cistern
inlet, (iii) adding salt or other admixtures that seal
the soil surface, reduce inltration and increase
runoff. The rst two methods are commonly used
in east Mediterranean countries such as Egypt,
Tunisia and Syria. Addition of salt or admixtures in
the soil is not common, because of the short-lived
effect and the possibility of affecting the qual-
ity of drinking water. People generally choose a
rocky catchment area, which has low inltration
and high runoff efciency.
Workforce and time requirements
Puncturing the roof rock and excavating the
chamber requires skilled labor. Punching and de-
veloping the hole takes 2-3 skilled workers about
two weeks, and soil excavation takes 4-5 work-
ers 1-2 months. Construction of the superstruc-
ture and sealing the chamber against seepage
requires a mason. Two masons and two laborers
could complete this task in 3-4 weeks. Depending
on the soil type and workers’ skill, a cistern of 150
m3 can be constructed in 3-4 months; mecha-
nized drilling through rock could reduce this time.
Safety measures during excavation
Under-designed or carelessly constructed cisterns
can be damaged or parts of the structure may
collapse. The following safety measures can re-
duce or eliminate the risks of structural collapse.
Select sound and compact rock at least 50
cm thick. Fractured or thin multiple-layered
rock can fail
Puncture the rock carefully, to avoid cracking
During excavation, leave one or two soil
columns intact, to support the rock cover
against the impact of excavation activities.
As a rule of thumb, the unsupported span of
rock should not exceed three times the rock
thickness
While excavating the sub-surface soil, con-
sider the slope stability. Widening should be
done gradually
Avoid extra load on the rock due to machin-
ery or dumped excavated material. This may
cause collapse of the cistern during construc-
tion
Sealing the soil surface with plastic sheet or special
chemicals can substantially reduce inltration and
increase run-off.
Compaction of micro-catchment surface reduces
inltration, helping to induce runoff.
Traditional technologies for dry areas 15
Construct the cistern during the dry pe-
riod, when soil moisture levels are low, and
complete the construction before the rainy
season begins. Do not work with moist soil,
because soil moisture and water seepage
reduce structural stability.
Operation and maintenance
The cistern water harvesting system consists of
a catchment surface, collection arrangement,
and a sub-surface water storage chamber. The
system is easy to operate and requires minimal
attention. Manual buckets, hand-driven pumps
or motorized pumps are used to draw water from
the cistern. Although laborious, the bucket is most
commonly used. Many hand-driven pumps have
been installed to draw water for domestic and
animal use, and motorized pumps for irrigation
using drip or sprinkler systems. There are two main
maintenance requirements: prevent the entry of
contaminants, and periodically clean the storage
chamber. Poor maintenance is usually due to
lack of knowledge or lack of money.
In dry areas with short rainy seasons, cistern
catchments usually remain unused for 7-8 months
per year. Many changes that reduce water
quantity and quality can occur during this period;
particularly vegetation growth, animals trespass-
ing and damaging the surface, and accumula-
tion of leaves and debris. Maintenance opera-
tions must be done before every rainy season:
compaction/treatment of loose soil patches,
repairing large cracks in paved catchments,
repairing of treated material (articial sheets or
sealant), repairing of ridges and ditches, de-
vegetation, and removal of leaves, debris and
logs. Fencing the micro-catchment partly or
completely and diverting the season’s rst runoff
away can reduce maintenance needs and sig-
nicantly improve water quality.
The deposition of sediment and biomass reduces
chamber storage capacity and adversely affects
water quality. These deposits must be removed
periodically. A sediment trap before the cistern
inlet can help reduce the entry of sediments.
Lack of regular maintenance can be detrimental
to cistern function and result in high rehabilitation
costs. Leakage of stored water is occasionally
reported; in these cases some treatment of the
storage chamber may be required. Maintenance
of the superstructure (inlet, outlet, approach
channel, mouth and platform) is simple and can
be performed by unskilled labor at little cost.
Common damage to cisterns
The most common major damage is the collapse
of underlying soil, rock roof slab, or both. This is
usually caused by serious water leakage through
ssures or cracks, fragmented or thin rock, natu-
ral hazards, or excessive overburden. Collapsed
cisterns are a major setback with both socioeco-
nomic and environmental implications: loss of
investment, loss of the primary freshwater source,
serious local damage to the land, poor quality of
stagnating water, and related implications such
as smell and disease. There have been occa-
sional mishaps of animals or humans falling in and
damaging cisterns.
Examples of
damage to
cisterns
Rainwater Cisterns
16
Rehabilitation of a collapsed system is difcult
and may require a large investment. However,
damage to the superstructure (inlet, mouth and
shaft) can be repaired with only moderate effort
and money. Alterations in the catchment area,
either naturally or by human action, can seriously
affect the cistern’s water harvesting potential.
Construction of roads, ridges, or culverts to divert
ow has led to the abandonment of some cis-
terns in the Mediterranean region. Before devel-
oping other infrastructure, planners must consider
whether (and to what extent) existing cisterns will
be affected.
Sedimentation in cisterns
User experience is that accumulated sediment
must be removed from the cistern every 4-5
years, which adds to recurring maintenance
costs. Soil erosion and debris/log ows from the
catchment are the main sources of sediment.
Flow concentration by water harvesting can
increase sediment entry into the cistern. Steep
slopes and weak soil structure in the catchment
area also increase sediment production. Vegeta-
tion cover in the catchment can reduce sedi-
ment, but also reduces runoff and may reduce
water quality below drinking standard. Sediment
can be reduced by treating problem spots in
the catchments, through compaction of loose
patches, treatment with impermeable mem-
branes, and breaking the steep land slopes. A
sediment-settling basin immediately upstream of
the entry point can signicantly reduce sediment
inow.
Maintaining water quality
Drinking water must meet microbiological, bio-
logical and physico-chemical quality standards.
Runoff water carries organic and non-organic
materials from the catchment into the cistern.
Several epidemic diseases are caused by bac-
terial contamination of water. Animal manure
can be the major source of the bacterium Esch-
erichia coli and other pathogenic microorgan-
isms and parasites. The rst runoff of the season
generally carries an abundance of such organic
matter. A water quality study by the Qasar Rural
Development Project in northwest Egypt (Vet-
ter 1994) found very high numbers of E. coli cells
(1000-10,000 times the WHO recommendations)
in 20 cisterns and four sub-surface reservoirs. Total
dissolved solids were 149-233 mg per liter. They
concluded that cistern water under natural con-
ditions did not meet health standards for human
consumption.
The following measures can improve the quality
of cistern water:
Keep the catchment clean or clean it before
the rainy season begins
Fence the catchment area to exclude ani-
mals
Keep a separate wooden or metal trough or
lined ditch or animals to drink from. This helps
keep the animals away from the cistern and
outside the catchment perimeter
• Divert the rst runoff and use it for agriculture,
do not let it ow into the cistern
Provide a settling basin to reduce entry of
sediment into the cistern
Whenever possible, have separate cisterns for
drinking from those for animal and irrigation
use
Boil cistern water before drinking it.
Well designed cistern, with settling basin and
sediment trap.
Traditional technologies for dry areas 17
In rural dry areas like northwest Egypt, demand
for water is growing, due to rapid population
growth. The supply of water of acceptable
quality is inadequate. Simultaneously, suitable
locations for building rainwater cisterns are also
diminishing. The solution would be to improve the
efciency of existing cisterns, to make more water
available with little investment. The performance
of cisterns is limited by inefciencies in collection,
storage and water use.
Improving water collection
efciency
The water collection efciency (WCE) of a cistern
system is the ratio of water collected by the cis-
tern to the rainwater received in the catchment.
WCE depends on catchment characteristics
such as soil, land use and topography that affect
runoff. The main catchment losses are inltration,
water retention in micro depressions and evapo-
ration, which may reduce water supply from the
catchment. If the approach to the cistern inlet
is poorly designed, a large proportion of event
runoff could be lost. Improvements in approach
channels and introduction of settling basin can
considerably improve WCE and reduce sedimen-
tation of the cistern. Catchment size and shape
are also important. The following guidelines can
help induce runoff and improve WCE.
Select catchment area with rock or com-
pacted soils. Avoid sandy soils because they
have high inltration rate and are not suitable
for runoff production
Clean the catchment, remove major vegeta-
tion, and improve the loose patches either
by compaction or by treatment with some
impermeable material. Grading the uneven
parts can also improve the runoff efciency of
the catchment
Construct the cistern in the areas where maxi-
mum ow converges. Alternatively, build a
ditch and/or ridge to guide ow towards the
cistern inlet
Provide an inlet of adequate size.
A study (IDRC 1996) looked at ve cisterns in
the coastal area of northwestern Egypt. One
cistern was not evaluated due to leakage. The
other four had WCE of 94%, 69%, 43% and 6%;
i.e. only one of the ve cisterns had good WCE.
A GIS-based study indicated that appropriate
placement of these cisterns were not located at
optimal places in the basins; more appropriate
location could improve WCE by 25-50% in each
case. This illustrates the importance of cistern
location to WCE.
Increasing water storage efciency
Cistern storage efciency is the ratio of the
amount of water stored in the cistern to the
amount of water supplied by the catchment at
the cistern’s inlet. Ideally, the entire runoff of the
rainy season should be stored, but this is rarely
possible because of storage limitations. Storage
can be increased by building new or larger cis-
terns and/or by multiple lling of existing cisterns
during the rainy season.
With new cisterns being built, there are few suit-
able locations available for additional cisterns
in northwest Egypt. At locations unsuitable for
cisterns, other water-harvesting structures have
been built as a substitute. These include sub-sur-
face concrete reservoirs, stone-masonry circular
tanks and circular tanks of composite sections
(stone masonry walls with concrete oor and
slab). However, these structures involve much
higher construction cost per cubic meter of stor-
age, compared to cisterns.
Improving Cistern Efciency
Newly built cistern in northwest Egypt, with approach
channel and settling basin.
Rainwater Cisterns
18
Experience shows that during the rainy season,
most catchments produce runoff larger than
cistern storage capacity. Improvement of exist-
ing catchments could further increase runoff.
Multiple lling of cisterns (more than once per
season) could capitalize on any additional runoff.
Using cistern water from a previous rainfall event
before the next event, creates additional stor-
age space. The emptied water could be used or
stored elsewhere in tanks for later use. One lling
usually meets basic human and animal needs,
and any extra water is available for agriculture.
Fills early in the season may be used for irrigation,
with subsequent or nal lls kept for domestic use.
Additional water can stabilize crop yields and
reduce the risk of crop failure, and soil moisture is
a low-cost storage method with minimal evapo-
ration losses.
Determining the multiple lling
potential of a cistern
The possibility of multiple lling depends on the
number of runoff-generating rainfall events. Data
on daily rainfall, and preferably detailed data on
rainfall events, can be used to assess catchment
runoff potential. IDRC (1996) suggested a rainfall
of 5 mm as the threshold value for runoff genera-
tion in northwest Egypt. At Matrouh (Fig. 6) rainfall
events of 5 mm will occur six times a year with a
probability of 80% and three times a year with a
probability of 90%. A 10 mm rainfall event will oc-
cur once a year with 90% probability, and three
times a year with 80% probability. The curves in
Fig. 6 provide a guideline for relling cisterns at
Matrouh.
Dry and wet years were computed using 48 years
of Matrouh data (Fig. 7). The criteria used: wet
years had annual rainfall greater than 125% of
long-term average, dry years had rainfall less
than 75% of average (Subramanya 1995, Rossi et
al. 2003). There were 18 dry years (38%), 13 wet
years (27%) and 17 average years (35%). Eight
years had rainfall less than half the long-term
average. This suggests that a design based on
average annual rainfall may fail to collect the
desired amount of water two years out of ve;
acute water shortage may occur in 17% of sea-
sons (about one year out of ve). Three-year av-
erages showed four dry spells and one severe dry
spell. Given this variability, cisterns must be based
on a conservative design, so that a reasonable
amount of water is available even during dry
years. This consideration is also critical for cistern
operation and management.
Cistern water for agriculture
People in many areas such as northwest Egypt,
Syria and Palestine also use cistern water for
agriculture. Nevertheless, due to limited supply
this should be restricted to high-value crops, and
to specic stages of these crops, to establish fruit
trees and to stabilize yield. The water from the
rst rain of the season, because of potentially low
quality for drinking and domestic use, can be
used for irrigation.
Figure 6. Probability of occurrence of 5 and 10 mm rainfall events at
Matrouh, northwest Egypt.
Traditional technologies for dry areas 19
Cultivating high-value crops
In northwest Egypt, cistern water is used to estab-
lish g and olive trees and home vegetable gar-
dens. It is also used to establish nurseries and for
supplemental irrigation. Supplemental irrigation, if
applied at the right time, can double or triple fruit
yields and thus substantially increase the farmer’s
income.
Efcient irrigation techniques
Techniques such as drip irrigation can reduce wa-
ter losses. They can be used for vegetables and
trees, and are particularly relevant for protected
(greenhouse) agriculture. Manual hose-irrigation
for small orchards and vegetable plots is labor
intensive, but feasible if cheap or family labor is
available. Flood or sprinkler irrigation involves high
water losses, and should never be done using cis-
tern water. Conjunctive use of rainwater harvest-
ing (using dikes) and cistern water for supplemen-
tal irrigation, can help support agriculture and
stabilize crop yields.
Improving cultural practices
Improved soil, crop and water management
practices should be encouraged. Cultural prac-
tices that ensure balanced inputs and services
can substantially increase production from a
given amount of water. Tillage, fertilizers and pest
control are particularly important. Weed control,
sowing time, seeding rate, irrigation scheduling
and improved crop varieties are also important.
Water demand by a crop can be reduced by
using water and soil conservation measures such
as mulches, and facilities to protect crops against
climatic extremes.
Figure 7. Inter-annual rainfall variability at Matrouh, showing dry and wet
years.
Olive trees are a major source of livelihoods in
northwest Egypt, but require supplemental irrigation.
Cisterns are a viable option.
Cistern water is normally for household use; but it can
also be protably used to cultivate high-value crops
in greenhouses.
Rainwater Cisterns
20
Rainwater cisterns are an effective, practical
means of storing water in dry environments,
such as northwest Egypt. They can help meet
water demand for domestic and livestock use
Cisterns are a good source of freshwater for
supplemental irrigation to orchards (e.g. olive
and gs in northwest Egypt) and a major
contributing factor to Bedouin livelihoods in
the area
Cisterns are a reliable, renewable source of
water and are widely used by local commu-
nities. They are low-cost, and can be eas-
ily built and managed by the communities
themselves
Water collection, storage, and use efcien-
cies of existing cisterns can be improved,
greatly increasing the return on investment
Non-availability of long-term rainfall data in
the dry areas is a major constraint for cistern
designers. Knowledge of long-term spatial
and temporal rainfall distribution can greatly
improve the development and management
of rainwater cisterns
Water contamination can be a health risk.
Sediment traps and grating at the inlet can
reduce levels of contamination. However, it is
recommended that cistern water be treated
before drinking, to meet health standards.
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Matrouh, northwest Egypt.
Wahlin L. 1997. The family cistern: 300 years of household
water collection in Jordan. In: Ethnic encounter and culture
change (M’hammed S M and Vikør KS, eds). Papers from the
3rd Nordic conference on Middle Eastern Studies, Joensuu in
the Finnish Karelia, 19-22 June 1995, Centre for Middle Eastern
and Islamic Studies, University of Bergen, Norway. C. Hurst &
Co (Publishers) Ltd., London, UK.
Conclusions
References
... Analysis of the likelihoods of storms in the locality is needed to help keep the last storm's stored water for later use. The same strategy can be applied for the enhancement of cistern storage (Ali et al. 2009). One however, needs to watch for downstream consequences as related to water rights (Bouma et al. 2011). ...
... Availability of a supplemental source of water, such as groundwater, would be the optimal solution. Water harvesting reservoirs and cisterns can be used to provide supplemental irrigation water (Ali et al. 2009). As indicated earlier, climate change is likely to intensify droughts, but also provides opportunity for more runoff to be harvested through more extreme events. ...
Article
Water resources in dry environments are becoming scarcer, especially under the changing climate. In response, rainwater harvesting (RWH) is being reemphasized with calls to revive the practice. Ancient knowledge on RWH-mainly the collection through runoff, storage, and use of rainwater for various purposes-is still relevant, especially for dry environments. However, many old practices and technologies may not be suitable or feasible for the present and future. Little has been done to modernize and (or) develop new practices and technologies based on ancient indigenous knowledge. Modernizing old practices or developing new ones and using them in integrated rangelands restoration packages with enabling policy environment can unlock their potential in many water-scarce regions of the world. This paper reviews the state-of-the-art of micro-catchment rainwater harvesting (MIRWH) in dry environments and discusses the opportunities available and the major obstacles faced in using it to restore degraded agro-pastoral ecosystems and support their sustainability. The review highlights the knowledge behind it, the practices developed over the years, and their relevance to today and the future. The paper indicates areas of modernization that can make it more feasible for the future of the dry environments, especially their role in mitigating and adapting to climate change. Conventional and passive approaches to restoring/rehabilitating degraded dry agro-pastoral ecosystems are either too slow to show an obvious impact or not progressing satisfactorily. One main reason is that, because of land degradation, the majority of rain falling on such ecosystems and needed for revegetation is lost with little benefit being gained. Adopting a more progressive intervention to alter the processes of degradation and move towards new system equilibrium is required. MIRWH can enable a large portion of this otherwise lost rainwater to be stored in the soil, and, if used in an integrated packages including suitable plant species and sound grazing management, it may support meaningful vegetation growth and help system restoration. The Badia Benchmark project, implemented by ICARDA in Jordan and Syria, has demonstrated the potential for adoption at large scale in similar environments. This case study illustrates the potential and the constraints of this practice.
Chapter
Rainwater harvesting is an ancient practice that helped in meeting basic water needs and reduced water shortages mainly in arid and semi-arid regions. Rainfall, through runoff, can be captured downstream of a suitable “catchment” area. The capture and storage of rainwater can be beneficially used. Harvesting water depends not only on the rainfall amount, but also on its pattern and intensity and on the catchment and storage conditions. Storage is a vital component of rainwater harvesting systems and can be surface or subsurface reservoirs or simply a soil profile. Uses include domestic, agriculture, industrial and environment sectors. Micro-catchment rainwater harvesting (MIWH) systems are based on having a small runoff catchment, normally at the household or farm level. In MIWH, runoff flows as sheet flow downstream to a storage facility to be used later for various purposes. Among the most common MIWH types are the Household systems including rooftops and cisterns and the Farm and Landscape systems including contour ridges, bunds, small runoff basins and strips. This chapter provides an overall description of the types, uses and limitations of MIWH. It also presents cases where MIWH plays an important role in providing necessary water for people and agriculture in addition to combating desertification and coping with climate change in dry environments. The implementation of those systems, however, face several technical, social, financial, and environmental constraints. Recommendations to help overcoming those constraints are provided for the rural dry environments where the need for water and food is critical.
Book
Full-text available
This Training Manual summarizes the major components of water harvesting techniques practiced in valleys, where channel flow is the predominant source of water. It covers four specific technologies adaptable by smallholder farmers. These are small earth dams, weirs, subsurface dams and sand dams. For each technology, the salient characteristics of the technology are described, as well as the planning, design, construction, management operation and maintenance. This manual is meant to improve the skills of engineers, technicians, extension workers, managers and practitioners engaged in water harvesting, especially those working in smallholder agriculture in Africa.
Book
Full-text available
This Training Manual summarizes the major components of water harvesting techniques practiced using open surfaces as catchment areas, where surface flows are the predominant source of water. It covers four specific technologies adaptable by smallholder farmers in the Nile Basin countries. These are (i) roof catchments, (ii) underground tanks, (iii) pans and ponds, and (iv) rock catchments. For each technology, the salient characteristics of the technology are described, as well as the planning, design, construction, management operation and maintenance.
Book
Full-text available
This Training Manual summarizes the major components of water harvesting techniques practiced using open surfaces as catchment areas, where surface flows are the predominant source of water. It covers four specific technologies adaptable by smallholder farmers. These are (i) roof catchments, (ii) underground tanks, (iii) pans and ponds, and (iv) rock catchments. For each technology, the salient characteristics of the technology are described, as well as the planning, design, construction, management operation and maintenance. This manual is meant to improve the skills of engineers, technicians, extension workers, managers and practitioners engaged in water harvesting, especially those working in smallholder agriculture in Africa. It is meant to inform, educate, enhance knowledge and practice targeting smallholder agricultural livelihoods
Article
Water harvesting techniques (WHTs) improve the availability of water, which is essential for growing crops, especially in arid and semi-arid areas. A decision support approach can help in the selection of WHTs suitable under site-specific bio-physical and socio-economic conditions. This paper describes a participatory approach for the selection of suitable WHTs in watersheds in (semi) arid regions. It builds on a database of suitability indicators for WHTs, which was developed by integrating worldwide knowledge on their suitability. Once developed, the approach was applied on a case study for WHTs in the upper Geba watershed in northern Ethiopia. First, based on evaluation criteria and participants' scientific and local knowledge, a pre-selection of most promising WHTs took place in a multi-stakeholder workshop. Next, the suitability indicators and a GIS-based multi-criteria analysis (MCA) were used to identify suitable areas for these WHTs. The results of the MCA were presented to stakeholders during a second stakeholder workshop. At this workshop, a final selection of WHTs to test was made based on a participatory ranking of WHTs using economic, ecological and socio-cultural criteria. The MCA approach was validated by comparing the predicted suitable areas with the already existing WHTs in the watershed. This led to the result that 90% of the existing check dams and 93% of the percolation ponds were correctly identified by the approach. We conclude therefore that this approach can be successfully applied for the participatory selection of WHTs and the identification of suitable areas for their implementation. Given that this approach is based on the newly developed database of WHTs, it can be easily applied in other (semi) arid regions.
Book
Full-text available
Significant vulnerability of water systems to drought is a common issue of water resources management in Mediterranean regions. This is due both to the increasing occurrence and severity of drought events and to the growing demand for municipal, tourist, and agricultural uses. The INCO-DC project entitled "A Decision Support System for Mitigation of Drought Impacts in the Mediterranean Regions" (DSS­ DROUGHT) addresses this issue, contributing to an improved management of water­ supply systems for irrigation, which represents the most consumptive sector of water resources uses in the Mediterranean region. In order to develop a comprehensive approach toward improved operation of irrigation systems under drought conditions, the project was developed around the following five main, strictly interconnected tasks: Identification of drought characteristics at a site and over a region Modelling irrigation management under conditions of water scarcity Modelling operation of water supply systems under drought conditions Integration of the developed methodologies within a Decision Support System software package Definition of requisites for Drought Watch Systems The research resulted in an advancement of knowledge through in-depth analysis of innovative methodologies, the development of tools to help decision-makers in coping with droughts through the implementation of the developed procedures in software packages, and the application of these tools to the case-studies identified by partners in their countries.
Article
Full-text available
"Dry areas occupy over 95 percent of the total lands of West Asia and North Africa (WANA) region. The area is dominated by a Mediterranean-type climate characterized by cool and rainy winters and temperate dry summers. Mediterranean sub-climates are usually differentiated by the length of the summer drought period and the temperatures during winter and summer."
Article
In arid and semi-arid regions, the scarcity of water can be alleviated by rainwater harvesting, which is defined as a method of inducing, collecting, storing, and conserving local surface runoff for agriculture. Rainwater harvesting can be applied with different systems, and this dissertation deals with the system of micro-catchments. A microcatchment consists of a runoff area and a basin area in which a tree is planted. The purpose of this study was to develop a design procedure for micro-catchments, applicable to environmental and human conditions prevailing in developing countries. Underlying the design procedure is an analysis of the water balance of the system.The design method is based on a prediction of actual transpiration by the numerical soil-water-balance model SWATRE, while the runoff component is predicted by a runoff model. The design- aims at sufficient soil water being available in an average rainfall year. Deep percolation losses occur in wet years, and water shortages in dry years. A tree suitable for these conditions is able to withstand dry periods and drought years. The practical problem selected for this study was the establishment of Neem windbreaks in Niger and Nigeria. Points to consider in the design are the seasonal distribution of rainfall, the soil hydraulic conditions, and the tree hydrological/ physiological characteristics.The theory of four surface runoff models is presented. These models are compared in their capability and accuracy to predict runoff volumes for micro-catchment design and in their model concept, structure, parameters, and input data requirement. A kinematic-wave model with depression storage and a linear regression model are considered the most suitable for micro-catchment design. The theory of the soil-water-balance model is discussed, as is the calibration of this model with data from Sede Boqer in the Negev Desert. The application of the model for micro-catchment design is demonstrated for an extremely and zone and an and zone in the Negev Desert.The extremely and zone is too dry for rainwater harvesting from micro-catchments, larger catchments being required there. In the and zone, the basin areas should be approximately 40 m 2for each tree, and the runoff areas 60 m 2. The design approach is applied to five weather stations in Niger and northern Nigeria where data were available. Data from a Neem windbreak at Sadoré in Niger were used to calibrate the model. Data from Niamey, near Sadoré, were used to compare runoff prediction with two runoff models and to predict micro-catchment design. The combination of a runoff-depth model and the soil-water-balance model was used to predict microcatchment design at Sadoré, and Tahoua in Niger and at Sokoto and Katsina in Nigeria.The conclusion of the design predictions is that the required runoff area per tree is about 40 m 2at Tahoua and about 20 m 2at Niamey, Sadoré, Sokoto, and Katsina. With such runoff areas, a good growth of trees could be achieved at degrees varying roughly from 40% of a certain target transpiration at Niamey, 50% at Sadoré, 80% at Sokoto, and 100% at Katsina. The overall conclusion is that, in and and semi-arid zones, runoff from small areas such as micro-catchments is an important potential source of water for the establishment, development, and growth of trees. A supply of runoff water can make the difference between death, survival, minimum development, and good growth of trees. Especially in dry years, the runoff water can considerably improve the environmental conditions in which the trees have to grow.The data required to apply this approach and arrive at a preliminary design are discussed. Rainfall and evaporation records are needed to supply important weather data. Data on topography, soil profile, soil hydraulic functions, and tree hydrological characteristics can be measured or estimated in the field, or determined in a laboratory from samples. With a preliminary design, well-conceived field experiments can be set up. As more data become available from the field, the design can be adjusted and worked out in detail for a particular location.The only potential alternative method of water supply to a windbreak would be trickle irrigation. But this would enhance the development of a shallow root system and would require a source of water, high capital investment, and irrigation management skills. All these requirements are difficult to realize for a windbreak. Instead, for this application, rainwater harvesting from micro-catchments is suitable, cheap, good, and efficient. Rainwater harvesting should be seen as complementing irrigated agriculture, rather than competing with it. Irrigated agriculture is practised on the best soils, where water is available to grow field crops. Rainwater harvesting is a good alternative on marginal lands where irrigation water is not available. Because of dry periods and drought years, rainwater harvesting works best for deep-rooting, drought-resistant trees.The technology involved is not complicated and can easily be adapted to local conditions of climate, soil, and trees. In many of these areas, there is a lack of water, wood, food, and shade, while wind erosion is a major problem. Windbreaks and shelterbelts can serve both the local population and the environment. Once the trees have been planted and the runoff areas constructed, some annual maintenance is needed but no continuous care. This is important for nomads, who are not farmers. Windbreaks demarcate and protect farmland, while large-scale shelterbelts consisting of different types of trees and bushes also serve nomads who do not settle. Microcatchments also reduce soil erosion by water, because they control surface flow. In addition, deep percolation in wet years recharges the groundwater. This can help to redress an upset regional water balance and combat desertification.
Article
In arid and semi-arid regions, the scarcity of water can be alleviated by rainwater harvesting, which is defined as a method of inducing, collecting, storing, and conserving local surface runoff for agriculture. Rainwater harvesting can be applied with different systems, and this dissertation deals with the system of micro-catchments. A microcatchment consists of a runoff area and a basin area in which a tree is planted. The purpose of this study was to develop a design procedure for micro-catchments, applicable to environmental and human conditions prevailing in developing countries. Underlying the design procedure is an analysis of the water balance of the system.The design method is based on a prediction of actual transpiration by the numerical soil-water-balance model SWATRE, while the runoff component is predicted by a runoff model. The design- aims at sufficient soil water being available in an average rainfall year. Deep percolation losses occur in wet years, and water shortages in dry years. A tree suitable for these conditions is able to withstand dry periods and drought years. The practical problem selected for this study was the establishment of Neem windbreaks in Niger and Nigeria. Points to consider in the design are the seasonal distribution of rainfall, the soil hydraulic conditions, and the tree hydrological/ physiological characteristics.The theory of four surface runoff models is presented. These models are compared in their capability and accuracy to predict runoff volumes for micro-catchment design and in their model concept, structure, parameters, and input data requirement. A kinematic-wave model with depression storage and a linear regression model are considered the most suitable for micro-catchment design. The theory of the soil-water-balance model is discussed, as is the calibration of this model with data from Sede Boqer in the Negev Desert. The application of the model for micro-catchment design is demonstrated for an extremely and zone and an and zone in the Negev Desert.The extremely and zone is too dry for rainwater harvesting from micro-catchments, larger catchments being required there. In the and zone, the basin areas should be approximately 40 m <sup> 2 </SUP>for each tree, and the runoff areas 60 m <sup> 2 </SUP>. The design approach is applied to five weather stations in Niger and northern Nigeria where data were available. Data from a Neem windbreak at Sadoré in Niger were used to calibrate the model. Data from Niamey, near Sadoré, were used to compare runoff prediction with two runoff models and to predict micro-catchment design. The combination of a runoff-depth model and the soil-water-balance model was used to predict microcatchment design at Sadoré, and Tahoua in Niger and at Sokoto and Katsina in Nigeria.The conclusion of the design predictions is that the required runoff area per tree is about 40 m <sup> 2 </SUP>at Tahoua and about 20 m <sup> 2 </SUP>at Niamey, Sadoré, Sokoto, and Katsina. With such runoff areas, a good growth of trees could be achieved at degrees varying roughly from 40% of a certain target transpiration at Niamey, 50% at Sadoré, 80% at Sokoto, and 100% at Katsina. The overall conclusion is that, in and and semi-arid zones, runoff from small areas such as micro-catchments is an important potential source of water for the establishment, development, and growth of trees. A supply of runoff water can make the difference between death, survival, minimum development, and good growth of trees. Especially in dry years, the runoff water can considerably improve the environmental conditions in which the trees have to grow.The data required to apply this approach and arrive at a preliminary design are discussed. Rainfall and evaporation records are needed to supply important weather data. Data on topography, soil profile, soil hydraulic functions, and tree hydrological characteristics can be measured or estimated in the field, or determined in a laboratory from samples. With a preliminary design, well-conceived field experiments can be set up. As more data become available from the field, the design can be adjusted and worked out in detail for a particular location.The only potential alternative method of water supply to a windbreak would be trickle irrigation. But this would enhance the development of a shallow root system and would require a source of water, high capital investment, and irrigation management skills. All these requirements are difficult to realize for a windbreak. Instead, for this application, rainwater harvesting from micro-catchments is suitable, cheap, good, and efficient. Rainwater harvesting should be seen as complementing irrigated agriculture, rather than competing with it. Irrigated agriculture is practised on the best soils, where water is available to grow field crops. Rainwater harvesting is a good alternative on marginal lands where irrigation water is not available. Because of dry periods and drought years, rainwater harvesting works best for deep-rooting, drought-resistant trees.The technology involved is not complicated and can easily be adapted to local conditions of climate, soil, and trees. In many of these areas, there is a lack of water, wood, food, and shade, while wind erosion is a major problem. Windbreaks and shelterbelts can serve both the local population and the environment. Once the trees have been planted and the runoff areas constructed, some annual maintenance is needed but no continuous care. This is important for nomads, who are not farmers. Windbreaks demarcate and protect farmland, while large-scale shelterbelts consisting of different types of trees and bushes also serve nomads who do not settle. Microcatchments also reduce soil erosion by water, because they control surface flow. In addition, deep percolation in wet years recharges the groundwater. This can help to redress an upset regional water balance and combat desertification.
Water harvesting -a manual for the design and construction of water harvesting schemes for plant production
  • W Critchley
  • K Siegert
Critchley W and Siegert K. 1991. Water harvesting -a manual for the design and construction of water harvesting schemes for plant production. FAO, Rome, Italy.
Adopting a sustainable livelihoods approach to water projects: implications for policy and practices. World Resources Institute ODI Working Paper 133. Overseas Development Institute
  • P H Gleick
Gleick PH. 1998. Adopting a sustainable livelihoods approach to water projects: implications for policy and practices. World Resources Institute ODI Working Paper 133. Overseas Development Institute, London.