Sand Dams Will Transform Millions of Lives
Transcript of Sand Dams Will Transform Millions of Lives
Sand Dams Will
Transform
Millions of Lives
The problem
• As many as 884 million people worldwide do not have
access to safe water(1) meaning their health and food
security are compromised.
• At least 830 million people worldwide are
undernourished(2).
• 80% of the world’s poor live in areas classed as
‘dryland’ – most rely on natural resources to survive.
• In drylands, rain falls in short intense rainy seasons -
much of the rainwater flows into seasonal rivers and
away into the ocean, leaving communities with water
for only short periods in the year.
• Regular drought, and the impacts of climate change
worsen this situation, increasing the periods of water
shortage.
The solution lies in capturing and storing the rain,
where and when it falls.
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Sources: (1) UNDP Human Development Report 2006, (2) FAO
Conservation leading to development
We support farmers to reduce extreme poverty through soil and water
conservation.
incomes
& health
food
production
water
supply
soil & water
conservation
Terraces
Sand Dams
Trees
Sand Dams
Pipelines
Water Tanks
Trees
Bee-keeping
Milk production
Trees
Inter-cropping
Crop diversification
Fruit & vegetables
Seed Banks
community self-help groups working together
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Soil and Water Conservation – 3 key ingredients
Un-terraced Land
• Up to 70% of water is lost
• Up to 250 tonnes of soil is lost per hectare
Water Scarcity
• 4-8 hrs are spent per day to collect water in
the dry season
• 8-12 hrs are needed during drought
Few Trees
• 95% of energy use in rural Africa comes from
trees
• Women spend 1-2 hours per day collecting
firewood
Terraced Land
• 95% of water is saved
• 97% less soil is lost
Local water source provided by sand dam
• 2-10 mn litres of water
• 0.5-1 hour to collect water in dry season
• 1-2 hours during drought
Tree Nurseries &
Planting
• Fuel self sufficiency
• Fruit and medicines
• Fodder & compost
• Increased soil &
water conservation
Without soil and water conservation: With terracing, trees & sand dams:
There are 3 key elements that interact to conserve soil and water:
terracing, trees and sand dams.
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Soil & water conservation enable improved
farming techniques
Benefits of soil and
water conservation
• more water and soil
in the farm
• more fertile soil
• less time collecting
water
• more time to farm
• potential to learn
and innovate
Sustainable solutions
• greater resilience to
drought
• increased food
production
• food security
• increased incomes
• improved health
Improved farming
• Inter-cropping
• Crop Diversity
• Fruit & Vegetables
• Zero-grazing
• Livestock & Bees
• Seed Banks
lead to lead to
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Community ownership and participation are essential
Excellent doesn’t give hand outs. We don’t impose solutions on
communities. We only support communities that have requested our
support.
• Farmers understand their problems and needs better than anyone else.
• Farmers talk. They share ideas and knowledge and learn from their peers.
• For long-term sustainability, the communities need to own their solutions
and manage them.
Our model enables farmers to choose their own solutions and solve their
problems themselves.
• Significant community labour is required for terracing, trees and sand
dams.
• The contribution of labour by farmers is equivalent to 40% of the total
project cost3.
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Sources: (3)
Community cooperation and participation in Kenya - “Mwethya”
• Cooperation, not competition: Mwethya,
meaning a group of willing workers, working
together, is an old tradition of the Kamba people.
• Building on tradition: When a community group
works with our partners, the Africa Sand Dam
Foundation (ASDF), they help other community
groups build sand dams and terraces, and in turn
are helped by other groups.
• The benefit is mutual: The work gets done faster
and the groups encourage and learn from each
other.
• Community exchanges: When communities visit
each other they motivate each other and share
ideas, technical expertise, and other resources.
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• Sand dams are the world’s lowest cost
method of capturing rainwater in dry rural
areas.
• They transform drylands into places where
people, plants and animals can thrive.
• To communities living in dryland areas,
sand dams are something of a miracle.
• Sand dams provide:
• Year-round water supply.
• Time and money for schooling, agriculture
and nutrition.
• Self-sufficiency for rural communities.
Sand dams will transform millions of lives
Sand dams work. We believe they will
transform millions of lives.
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What is a sand dam?
find a rock base in dry riverbed
build a reinforced concrete wall
A sand dam is a reinforced concrete wall built in a
seasonal riverbed to capture and store water beneath
sand, both filtering and protecting it.
A sand dam holds 2-10 million litres of water and is
the world’s lowest-cost rainwater harvesting solution.
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Seasonal rains quickly fill the dam with water and soil.
The soil is made up of silt and sand.
The heavier sand sinks behind the dam, whilst the lighter silt washes downstream.
How does a sand dam work?
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The sand accumulates until the dam is completely full of sand up to the spillway.
Water is stored within the sand making up 25-40% of the total volume.
This means that 2-10 million litres of water are captured - depending on the sand particle
size and the size of the dam.
How does a sand dam work?
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There are three main ways to abstract water from sand dams. The community decides on
the most appropriate option for them.
• Evaporation is reduced to a minimum when water is stored beneath sand.
• The sand also filters the water clean and protects it from parasite carriers such as
mosquitoes and snails.
• This reduces considerably the incidence of the world’s two biggest killers of children
under five: malaria and diarrhoea.
Getting water from sand dams
1. Scoop holes 2. Pipe filtration 3. Shallow wells
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Benefits of sand dams
Categories Indicators Before
Sand Dam
Construction
After
Sand Dam
Construction
Agriculture # of cash crops 1.5 2.8
% irrigated crops 37 68
Special aspects Water collection for domestic use
(minutes)
140 90
Water collection for live stock
(minutes)
110 50
Gender Average walking distance for
women to water (km)
3 1
Economic Income (US$/year) 230 350
Health % households suffering from
malnutrition
31.6 0
Source: Evaluation of sand dams, Albert Tuinhof of Acacia Institute
The benefits of sand dams are numerous: they improve water supplies, enable diversified
food production, improve health and incomes to name a few.
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Sand dams improve water supplies
• A sand dam creates a local, reliable, clean water
supply for up to 1,000 people for life.
• A sand dam stores 2-10 million litres of water each
season and recharges naturally.
• Held below the sand, water is prevented from
evaporating.
• A sand dam provides enough water for people to
drink, water their animals, and irrigate their crops.
A sand dam provides 1 person with clean water for life,
for just £10.
(Based on the typical sand dam in Kenya costing £10,000 and providing water for
1,000 people: Source Excellent Development).
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Sand dams enable food production
• Sand dams save farmers 2-12 hours every day.
• Time saved can now be invested in activities to improve
harvests.
• Having water nearby in the sand dams makes growing fruit
and vegetables possible.
• The water supply enables increased and diversified food
production.
• Farmers can irrigate crops even during the dry season.
£1 invested in agriculture and rural development generates a fourfold return Source: Adolf Kloke-Lesch, BMZ
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Sand dams benefit health & incomes
Water in sand dams is stored below sand. Unlike
open water dams or wells:
• Mosquitoes cannot breed – reducing the incidence
of malaria.
• Snails carrying the bilharzias virus cannot survive –
dramatically reducing the risk of diarrhoea.
• Animals cannot contaminate the water.
Thanks to a reliable, clean supply of water:
• Diets improve as farmers have time to improve
harvests and diversify crops.
• Incomes improve as people have time to spend on
livelihoods.
The UN estimates that every £1 invested in water
supply in developing countries delivers £6 in
increased incomes, health and education benefits. Source: Asia Waterwatch 2005
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Sand dams transform the environment
• Sand dams raise the water table in the area above and below the dam.
• Bio-diversity improves, as trees and indigenous species are able to thrive.
• Less than 3% of the water flowing downstream is captured by the dams meaning water
is not diverted away from downstream users.
• Sand dams reduce flood risks and increase downstream flow during dry seasons –
creating added benefit for downstream users.
View downstream from a sand dam in the Ilikoni Valley, Kenya.
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Source:
Sand dams offer excellent value for money
• Sand dams are the world’s lowest cost method of capturing rainwater in dry rural areas.
• Sand dams recharge naturally every season, storing 2-10 million litres of water year
round.
• Sand dams are built to last 50 years with no operational costs and require little or no
maintenance.
Technology Cost per 1,000 litres
Sand and subsurface dams 40p – 80p
Runoff open reservoirs £1.80 - £3
Underground tanks £2.40 - £14
Above ground tanks £18 - £60
Derived from Mati 2006 - SEARNET
Typical costs of rainwater harvesting technologies
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The potential for sand dams
• 40% of the world’s land is classified as drylands
• 2.3 billion people live in drylands
• 80% of the world’s poor rely on dryland resources
• 44% of the world’s food is produced in drylands
Source: UNDP
• Sand dams can be built anywhere where
there are seasonal rivers with sandy
sediment – conditions that are found
across the world’s ‘drylands’.
• However currently approximately 150
sand dams are being built per year
worldwide, mainly in Kenya. Excellent’s
mission is to change this.
Countries with examples of
sand dams or similar
structures.
Countries with regions suited
to sand dams.
Map derived from Excellent Development research 2009
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Where are sand dams found today
• There are references to sand dams (or similar structures) in the Mediterranean region
around 500 AD. They were also present in the 1800’s in Mexico and S.W.U.S.A, and
in the mid 1900’s in India and Namibia.
• Isolated examples found in Yemen, Jordan, Japan, Turkey, SW USA, Zambia, Burkino
Faso, Ghana, Ethiopia, Somaliland and Zimbabwe.
• First Kenyan dams built in 1950’s.
• Significant increase in the number of sand dams built in Kenya between 1980 and
2010, driven predominantly by the work of Utooni Development Project (UDO) and
Sahelian Solution (SASOL).
• Today approx.150 dams a year are being built, of which 100 are in Kenya by 3
organisations (ASDF, UDO and SASOL).
• Sand dams have recently been introduced into Mozambique, Ethiopia and Sudan
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Our Vision:
Sand dams will transform millions of lives.
Our Purpose:
• To support farmers in developing
countries to gain access to clean water
and grow enough food to eat and sell.
• To promote sand dam technology and
environmental conservation.
• To support organisations to implement
sand dams alongside food and water
programmes.
Excellent – Pioneers of Sand Dams
• Less than 150 sand dams are being built a year worldwide.
• Excellent’s goal is to enable 2,500 dams being built every
year by 2020.
• Meaning 3 million more farmers a year will gain access to
sustainable, clean water.
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Progress 2010-11
Uganda - WaterAid made a
learning visit from four
country offices to Kenya in
March 2010. WaterAid
Uganda has received
funding for a sand dam
programme and Excellent
and ASDF will provide them
with technical support.
Zimbabwe – Three staff
from the Dabane Trust
completed a learning visit to
Kenya in Jan. 2011 and are
planning a further visit of ten
team members in April 2011.
Excellent and ASDF will
support their programme to
build 21 dams by 2014.
Mozambique – We have
supported the creation of
CCM’s national sand dam
and agriculture programme.
Excellent facilitated a
strategy workshop to help
them think through all parts
of the programme. CCM
also completed a learning
visit to Kenya in Jan. 2011.
Kenya – UCCS completed a
learning visit to ASDF in
October 2010. Supported by
ASDF, we have also
enabled UCCS to pilot two
sand dams in Northern
Machakos in November
2010. We have been
planning for further support
for 2011-12.
Sudan – We supported SOS
Sahel Sudan to pilot sand
dams into their conflict
reduction programme, as a
way of managing the conflict
created by water shortages.
Kenya – We have signed a
strategic partnership with
ASDF to promote sand
dams, provide technical
assistance and learning
visits to Kenya.
We also funded 21 dams
and a food production
programme in 2010-11.
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Plans 2011-12 onwards
Uganda - WaterAid Uganda
has received funding for a
sand dam programme 2011-
14 and Excellent and ASDF
will provide them with
technical support. An initial
feasibility trip is planned for
September 2011. We have
also planned with WaterAid
UK strategic discussions
about a wider sand dam
initiative.
Zimbabwe – Ten staff from
the Dabane Trust will
complete a learning visit to
Kenya in April 2011. In
August 2011, Excellent and
ASDF will visit planned sand
dam sites and continue to
provide technical support for
their 21 dam programme
2011-14.
Mozambique – Having
funded the CCM Food &
Agriculture central team Jan
to March 2011; we are
agreeing how we can
support CCM in financial,
strategic and technical ways
during 2011-12.
Sudan – We are planning a
learning visit from SOS
Sahel Sudan to ASDF in
Kenya to share knowledge
on sand dam and agriculture
programmes during 2011.
Kenya – We are supporting
ASDF to develop their
capacity to provide both
learning visits to Kenya and
technical support overseas.
We are also supporting them
to develop their own
fundraising and donor
management capacity in
country.
Kenya – We are planning to
support a further pilot of five
sand dams with UCCS in
2011. We are also working
with ASDF to provide
technical capacity building to
UCCS in view of a full grant
management programme
during 2012.
India – We are currently
identifying potential partners
in dryland India to engage
with about sand dams.
We intend to carry out a
feasibility visit to a number
of NGOs in the first half of
2012.
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Why are sand dams not adopted more widely?
There are number of limitations to the wider adoption of sand dams:
• A lack of awareness. Sand dams are not in the ‘toolbox’ of water solutions that many
organisations support.
• A lack of technical knowledge and experience to design and construct sand dams.
• Terracing, tree planting and building sand dams is hard, physical work. It’s labour
intensive.
• Community engagement and ownership are essential. Engaging communities can be
time consuming, it needs dedicated face-to-face time.
• Sand dam technology needs to tested in new environments, it is not as simple as just
replicating what has been done in Kenya.
• Policies and funding often neglect rural drylands.
Sand Dams are a
simple and low-cost
technology but they
require hard work
and community
engagements.
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However, these limitations can be overcome by:
• Raising awareness of sand dams at all levels from
farmers to governments through a structured
advocacy programme.
• Demonstrating the benefits and impacts of sand
dams through completing research to collect
evidence.
• Increasing technical knowledge to design and build
dams through training, technical support and the
creation of learning resources for non-engineers.
• Showing more communities and organisations the
success of terracing, trees and sand dams through
hosting learning visits to Kenya and community
exchanges.
• Increasing understanding of sand dam application in
new environments through completing pilot projects.
• Engaging with and influencing policy makers and
funding agencies.
We want to raise
awareness of sand dams
at all levels and enable
other organisations to
learn about sand dam
technology.
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Excellent’s model to address these limitations
Activity Description
Strategic
Partnerships
• Develop partnerships with local NGO’s to deliver
integrated sand dam, food and water security
programmes.
Programme
Development
(including
sand dam
pilots)
• Test the application of sand dam technology in new
contexts.
• Structured process of testing sand dam technology in
new contexts including PESTLE (Political, Economic,
Social, Technical, Legal and Environmental) analysis.
Research • Conduct research, and support research organisations
to collect evidence that demonstrates the benefits and
impacts of sand dams.
Advocacy • Raise awareness of the role of sand dams in creating
food and water security in drylands.
• Influence policy makers and funders to support the
inclusion of sand dam technology as part of their
approaches and solutions to alleviating poverty in
drylands.
Learning
visits and
learning
resource
• Create learning resources, such as a Sand Dam Manual
(aimed at engineers) to enable organisations to gain the
knowledge to design and construct sand dams.
• Provide the opportunity for organisations to visit existing
strategic partners to learn about, and gain skills to apply
sand dam technology.
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Strategy for scaling up sand dam adoption
• Start small. Influence small scale
practice through supporting visits to
existing strategic partners.
• Increase the body of evidence to
demonstrate the benefits and impacts of
sand dams
• Utilise the success at small scale
practice and the increased research and
advocacy to influence policy
• Leverage the combination of small scale
practice success, policy, research and
advocacy to influence large scale
practice.
Influence
Policy
Influence Large-Scale Practice
Learning Resources
& NGO Visit Capacity
Enable
Small-
Scale
Practice
Research and Advocacy
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Conclusion
We cannot achieve our vision of transforming millions of farmers lives alone.
To enable 2,500 dams a year being
built by 2020:
• Many more people need to know
about sand dams.
• Many more people need to be
building sand dams.
• And many more people need to
advocate sand dams and their role
in achieving food and water security
in drylands.
• We need more strategic partners,
more research, more advocacy,
more training and learning materials.
• A combination of practice and policy
is needed, from the micro level
(grassroots community level) to the
macro level (government policy).
• And of course, to do this, more
financial investment.
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Appendix: Existing sand dam research
Examples of sand dam research institutions
• Vrije Univeristat, Amsterdam
• TU Delft University,
• Acacia Institute,
• RAIN Foundation,
• UNEP
Hut et al Effects of sand dams on ground water levels
L Borst et al (2005) Hydrology of Sand Storage Dams: A case study in the Kiindu
catchment, Kitui District, Kenya.
Jansen J. (2007) The influence of sand dams on rainfall-runoff response and water
availability
Jeroen Aerts et al (2007) Robustness of Sand Storage Dams under Climate
Change
Global maps
The maps on the following 7 slides show:
• World’s and Africa’s dryland regions
• World Poverty
• Water scarcity
• Food scarcity
• The impact of climate change on food production
Note the high correlation between dryland climate, poverty, water and food
scarcity.
Global climate: aridity
Africa: aridity
Yellow area: Drylands where
Precipitation/Evapotranspiration
< 60% and where Ephemeral rivers
(blue lines) are found.
Note: the mapping of ephemeral
rivers incomplete and in reality are
found across the yellow dryland
regions.
Source: RELMA, UNEP and CGIAR
research into the potential
application of sand dams
Global Poverty map
Global Water Scarcity
Examples of sand dam research
Vrije/TU Delft University, RAIN Foundation, UNEP
Global Water Resources
Global Food Scarcity
Impact of climate change on food production
Climate change in a typical river basin
Excellent’s comparison of water supply
technologies
TypeWater
technologyCost/m 3
Initial
Investment
Cost
Maintenance
Cost
Abstraction
Cost
Water
Quality
Environmental
ImpactsSustainability
Dams
Sand dams:
Infiltration gallery Very Low Medium Low V Very Low Very High Very Positive High
Dams
Sand dams: Scoop
holes Very Low Medium Very Low Very Low High Very Positive Very High
Dams Haffir/Earth dam Low Medium Medium V Very Low Very Low Positive Low
Tanks
Above ground
rainwater tanks High Medium Low Very Low High Neutral High
Tanks Underground tanks High Medium Low Very Low Medium Neutral High
Tanks
Rock catchment
with tank(s) High Medium Low Very Low Medium Neutral High
Wells
Wells: Open hand
dug Very Low Very Low Low Medium Low Neutral Very High
Wells
Wells: Hand dug
and pump Low Low Medium Low Very High Negative Medium
Wells
Wells: Hand
augered and pump Medium Medium Medium Low Very High Negative Medium
Wells Boreholes Very High Very High Very High Very High Very High Very Negative Very Low
WaterAid’s
comparison of water
supply technologies
How to build a sand dam
1. Community identifies 3 or more potential sites that meet their needs
2. Optimum site selected, design completed, materials quantified
3. Community collects rock, sand and water and land above dam site terraced
4. Legal agreements with adjacent land owners signed
5. Excavation of river sediment to bedrock for dam foundation
6. Weathered rock removed and fissures sealed with mortar
7. Infiltration gallery constructed upstream of dam connected to piped outlet or
pump
8. Timber formwork erected
9. Vertical steel reinforcement bars drilled into bedrock
10.Stone masonry (rocks bonded by sand and cement mortar placed in the
formwork
11.Horizontal lines of barbed wire every 30 cm binds the steel bars and rocks
12. Formwork removed after one day and dam watered morning and evening for
30 days to cure the cement