Once you have installed a RWH system it is a good idea to also set a system for monitoring.
How much water you are catching
How much of this you are using
How much you are recharging
This will help you to provide concrete evidence of the impact of rainwater harvesting
If the data is positive it will help to catalyse other people to follow in your footsteps.
How can you monitor quantity of water recharged?
Water level monitoring – using a water level indicator
Infiltration test – using a flow and water level meter
Frequency of monitoring – Monthly, pre and post-monsoon
Can arrive at trends of water table
Monitoring extraction from tubewell will give you total extraction. (Hours of pumping X yield of tubewell)
CSE has been regularly monitoring water levels in 21 model RWH projects.
What we found was that in the places where rainwater harvesting was undertaken, the water levels had not declined.
In the same period, there was a general decline in the water table in the areas of Delhi where the model projects were situated.