A commission for a sensory garden for a Nursery in oswestry, requires a water pump to be made so that it can be operated by the children of the nursery. The pump is to get water flowing down a channel approx 135mm wide, 75mm deep and approx 9m long. To which the children can float hand made wooden boats down. There is no means of electric available either!!
The question is how to build a water pump suitable?