By Col S G Dalvi (retd.)
According to Skymet Weather, Monsoon 2016 is likely to remain above than the normal at 105% (with an error margin of +/-4%) of the long period average (LPA) of 887 mm for the four-month period from June to September. Last two years country we experienced deficit monsoon. It is a very good news.
Marathwada receives around 800 mm of annual rain fall. Even if 50 % of rain fall deficit will have 400 mm of rain fall in the region. Let us analyse potential of 400 mm of rain fall. 1000 sf ft of catchment area like roof top of village houses, will receive around 40,000 liters of rain water. At 40 liters of daily authorization of water per person this is enough to cater for 200 days of water for family of 5 . This is over & above what is supplied by local body Govt. So the problem lies in lack of awareness every where. I have not considered the addition water available, due to the Rain Water Harvesting. Govt of Maharashtra has all GRs , rules & regulations for recharging of Ground Water using Rain Water Harvesting methods. However this has only remained on paper. Now is the time to make citizens all over aware of this. Provide them necessary help to execute these projects on village houses before coming monsoon.
I had visited a village Kamkaheda in Beed District some time back to spread awareness on Rainwater Harvesting.Some details are given below
22 x Bore wells
1 x open well
680 mm average annual rain fall
658 x Houses
5.26 lakh sq. ft. of roof top area of houses acting as rain water catchment area
3.15 crore litres the rain water potential of the roof top catchment area.
4000 population of village.
7875 liters of rain water per person annually.
At 40 liters per day per person, this village requires 5.84 crore liters of water. Rain alone can provide 3.15 crore liters ie around 54 % of annual water need of the village population. If groundwater table is recharged properly you tend to get much more or harvested water from the ground water. This I am quoting from my experience of working in this field for last 14 years.
All the stake holders especially Govt bodies at all levels must work on war footing to implement Roof Top Rain Water Harvesting in maximum villages.One of the most economical & easy to implement system is Roof Top Rain Water Harvesting. One has to channelise roof top rain water through rain water drain pipes, filters to bore well or open well. This will take care of recharging of groundwater aquifers. One must note the potential of rain water of their local area.
For 100 sq meter roof top catchment area, Annual average rainfall of 750 mm
100 x 750/1000 = 75 meter cube of rain water
1 meter cube of water = 1000 liters of water
so Mumbai will receive around 300,000 liters of water & villages in Marathwada with average annual rain fall 800 mm will get around 80,000 liters of rain water on roof top of 100 sq meter or 1000 sq ft. In a village in Marathwada family of 6 staying in a house with 1000 sq ft roof top area ,in normal monsoon will receive 80,000 liters of water sufficient to meet annual water needs of this family of 6.
This natural bounty is being wasted all over today. Monsoon is almost 2 months away. We need to supply them water but more important is to train them to execute RWH projects in village for better future. This will not only ease out water crisis problems but also help improve ground water table.
My sincere request to all ,to spread awareness among citizens about potential of Rain Water & benefits of Roof Top Rain Water Harvesting.
(Col S G Dalvi (retd.) is district manager (Pune) of the the Climate Reality Project, India and Director, Parjanya : Rain water Harvesting Consultancy)