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.

2

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

3

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.

4

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

5

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.

6

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.

7

• 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.

8

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.

9

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?

10

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?

11

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

12

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.

13

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).

14

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

15

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

16

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.

17

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

18

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

19

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

20

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.

21

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.

24

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.

26

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

27

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.

28

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