Rain Rain Come Again!
A good example of a "quick greening" solution where detailed analysis is required before being implemented! The cleverly avoided subject in rainwater harvesting is the rainfall volume and its inconsistency throughout the year. There will be high rainfall periods and low rainfall periods which means the harvesting is obviously volume dependent at that point of time! Taking average annual rainfall as the baseline gives a false impression on the projected harvesting volume - there will be dry periods and super-heavy rainfall which might mean much of the rain simply overflows the containment vessel. Taking into account this factor and the overall carbon emitted to build the tanks, piping and the use of pumping energy, the overall benefit to mother earth might fall into the negative!
What should be the solution?
1) Reconsider the need for fish pools or fountains! - Yes they add beauty but is the evaporation rate and pumping energy green? Some may say bodies of water help cool the surrounding but truth is that no reliable figures are availble on the actual benefit!
2) Think of plants that are native and can live within the weather condition - excellent solution simply because alien species of plants is not encouraged in the real "green" solution.
3) Use water facilities wisely and fittings that are water efficient - spending the extra on this means real savings - using less through efficiency!