How to get freshwater in coastal areas?

Tackling salinity and climate change in Bangladesh and The Netherlands

Reinier Visser Water resources specialist

Intro Acacia Water

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Context of water availability in coastal zones

•  50% of world population in coastal zones •  Fresh water availability under increasing pressure

–  Increasing demand –  Decreasing availability

•  Current water management systems under pressure –  Water follows function and focus on main water systems –  little urgency for efficient water use –  Lack of knowledge and the issue of perceptions –  Enough water, but in the wrong place at the wrong time

Increased vulnerability: decreasing access to sufficient water of good quality

We have options to adapt to these changes, but we will face many challenges

So what can we do?

•  Improve resources management •  Demand management •  Increase capacity

Strategy towards sustainable water management in coastal zones

•  Getting the facts on the table •  Making both the physical and the

institutional landscape more robust through an integrated landscape approach

•  More long term solutions; think small, not just big

Many buffering options

Example cases Bangladesh – The Netherlands: similar systems for different uses

–  Bangladesh – MAR for rural water supply –  The Netherlands – MAR for agriculture

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Bangladesh - MAR system

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Goal: Fresh water self sufficiency and reliable access safe water in saline areas

Advantages

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•  Improved year-round water availability

•  Improved water quality and reduced health risks

•  Suitable for local-scale application •  Cost-effective •  Resilient to disasters

Upscaling

•  20 systems tested, 75 additional systems being implemented

•  Over 1 million people could use this system within 3 target districts in Bangladesh

•  Many saline deltas world-wide •  Main challenges:

–  O&M and management –  Institutional setting

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Spaarwater (Save-water): agricultural water conservation in saline delta’s

Goal: Fresh water self sufficiency and optimized crop yields in saline areas

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Closing the cycles •  Testing different technologies, example Spaarwater Location Breezand

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CAPTURING STORAGE USE

Capturing and storing •  Source: 1.5 ha tile drainage via collector drain •  Storage

–  Subsurface storage (10m – 20m below surface) –  1 infiltration well & 3 abstraction wells (2 filters each) to enhance removal of biological

contaminants

ditch

üEC ûEC

Tile drainage

Filter

Subsurface storage

-10m

-20m

brakish water

fresh water

Optimizing water usage –  Subsurface drip irrigation and fertigation –  Real time monitoring (groundwater and soil

moisture) –  Real time control of water and nutrient flows

Subsurface drip irrigation

-10m

-20m

brakish water

fresh water

Drip lines

Moisture in the rootzone

Dry

Participatory planning process

Based  on  facts  and  knowledge  of  all  stakeholders;  sustainable  strategies  and  measures  are  dra7ed  and  eventually  implemented.    

Improved water management, a joint responsibility

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•  Participation of all stakeholders in water management and monitoring •  Decentralized water management enabled by new technology •  Local (user) monitoring data linked to central database

Cooperation between Acacia Water, akvo and SODAQ

The smartphone as a lab

Concluding remarks •  Bangladesh – The Netherlands, similar systems different use

–  Bangladesh low-tech low cost (manual operation) –  NL high-tech higher cost (automatic operation)

•  Many other solutions available, huge potential for improving water availability in coastal areas

•  Integrated approach to achieve sustainable strategies and measures •  All stakeholders participate

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More information: Bangladesh MAR system:

–  Video: Underground Freshwater Storage- a cross country learning –  Book:

Underground fresh water storage A practical solution to increase water security in saline deltas

Farming water supply systems:

–  www.dynamicwatersystems.nl –  www.spaarwater.com

www.acaciawater.com

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