piloting rainwater harvesting for mus in dire dawa, ethiopia

EVERY DROP COUNTS!

Sean Patrick- 26th June 2013

Piloting Rainwater Harvesting for MUS

Dire Dawa, Ethiopia –

The lessons

Sean Patrick- 26th June 2013

Sand dams & Subsurface dams

Small dam built on seasonal riverbeds,

the raised wall captures some of the surface runoff and stored within the coarse sand deposits

Wall is built above ground,

with a spillway to allow continuous flow of water downstream

Sean Patrick- 26th June 2013

Subsurface…

SSD- impervious wall constructed on a bedrock in a trench across the valley/stream

Wall is below ground and holds flow of a natural aquifer

Capacity for the dam increased easily by adding layer of concrete wall

Sean Patrick- 26th June 2013

The Lessons• Institutional arrangements, Coordination and

Harmonization,

• Determining technology choices

• Technical design considerations, and

• MUS Field implementation considerations

Sean Patrick- 26th June 2013

Institutional, Coordination and Harmonisation

• Participation is not a straight forward concept

• High capacity demands

• Lateral and diagonal communication very crucial though difficult

Sean Patrick- 26th June 2013

Technology choice

• Local resources available

• Topography factors

Sean Patrick- 26th June 2013

Technical design considerations

• MUS: proper needs and source assessment takes time

• Projects need to be flexible to accommodate possible design alterations– Gravity water– Deep trenching

Sean Patrick- 26th June 2013

MUS Field implementation

Financial implicationsCement vs clayMachinery vs local labour

Timing matters- flash floods

Sean Patrick- 26th June 2013

Challenges for Replication

Topographical suitability (RB 25metres, hilly, soil- sand and gravel, reservoir should be based upon impermeable bedrock,

High technical requirements Not readily available in rural communities…continued need for NGO support

Sean Patrick- 26th June 2013

Justification: Benefits Vs Cost

Undeniable need of clean water in arid and semi-arid areas

Highly effective method in areas with limited rainfall and dependable infrastructure

Dam capacity expansion is cheaper; raising the walls

Sean Patrick- 26th June 2013

Justification…

Strong community involvement, old system improved

Use of locally available resources and

• Substantial offshoot benefits: re-vegetations, landscape management, new ecological zones and agri-practises

Sean Patrick- 26th June 2013

Thank You

Sean Patrick- 26th June 2013