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WASH Cluster – Emergency Training

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DR4 1

DRAINAGE

Session 4

Drainage Solutions

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WASH Cluster – Emergency Training

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Design exercise

Task: Calculate the dimensions of a soakaway pit to drain wastewater from a communal shower area.

A. In your groups, list the information you need to be able to do the calculation

B. Do your assessment (ask the trainer the questions)

C. Do the calculation

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WASH Cluster – Emergency Training

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• Answer Following ….

Session Number here 3

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WASH Cluster – Emergency Training

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Exercise answer• Quantity of wastewater:10 families X 20 l water / family / day =

200 l of water / day• Infiltration capacity of soil (loam): 18

l/m2/day• Infiltration surface area required:200 divided by 18 = 11 m2

If the soakaway pit has a rectangular section 1m x 2m, it needs to be this deep:

11m2 divided by 6m = Approximately 2m.

1 m

2 m

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WASH Cluster – Emergency Training

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SOAKAWAY, what is wrong here?DR4

Photo courtesy of John Adams

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WASH Cluster – Emergency Training

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Group WorkIn your group each person chooses one

drainage option belowChampion your drainage solution and debate amongst the group;

• The pros and cons of the drainage option• When would you use this solution?

OUTLET TO WATERCOURSE SOAKAWAYINFILTRATION TRENCH OPEN CHANNELEVAPORATION PANS PIPES/SEWERS

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