Dark Zone to Flow

DARK ZONE TO FLOW

Few words of a wise old-man spoken to Rajendra Singh changed the path of Tarun Bharat Sanghs approach towards development. After that TBS never look back. It is Johad which made TBS a champion in the sphere of Rain-Water Harvesting. Till today, TBS constructed around 10,000 of johads with the contribution of villagers.

The impact of 25 years of tireless effort has brought about a significant increased from an officially marked dark zone to a water surplus zone.

Now begin with the story of the rivulet Arvari. The first step to make this stream alive was taken in 1987 by constructing a small Johad in a village Bhaota. Later seeing the advantage of johad, many villagers came forward to build such structures in their own areas. Now there was simply a craze for johads. And to this date, there are 375 RWH structures in the catchment area of the river Arvari.

Water in RWH structures raised the water table in the entire catchment area of the river. This in turn, enriched the forest in the same area. Forests and scrubs helped to retard the run-offs of monsoon waters. This way, in a decade, the river Arvari came to life from a dried up dead water-course. Today, the river-flow continues the year round.

Expert opinion R.N.Athavale, emeritus scientist at the National Geophysical Research Institute in Hyderabad, assessed the work done by TBS. His aim was to gauge the changes brought about by the RWH structures through certain estimates of the water balance of a typical river in the area. Here are some of his findings:

The annual average rainfall in the region is about 600 mm. Most of this rain (about 80 per cent) falls during the monsoon.

Before TBSs intervention in encouraging RWH, 35 per cent of the rainwater was lost immediately as seasonal run-off. Another 50 per cent was lost due to evaporation or transpiration.
Only 15 per cent of the rainfall naturally recharged the groundwater. Of this, 5 per cent became soil moisture, as the soil was too dry. Another 5 per cent constituted the base flow, implying the amount of groundwater returned to the surface stream or river. Of the remaining 5 per cent, some parts were tapped by wells and used, but the rest percolated to depths below the wells and stream beds.

After RWH structures were built, there was an additional recharge of groundwater to the tune of 20 per cent.
Though the base flow to the stream or river remained the same, there was an additional seepage (effluent seepage) of 17 per cent of rainfall to the river in non-monsoon months. This phenomenon contributed to the revival of the River Aravari and made it perennial.

Seasonal run-off has come down from 35 per cent of the rainwater to only 10 per cent.
There has been an increase in soil moisture: an additional 5 per cent of the rainwater is retained in the soil. Groundwater table has risen.

In all 5 per cent of the total rainwater is being used for irrigation, one-third of which is returned to the ground. It should be noted that the villagers have not been unscrupulous in drawing out groundwater.
About 22 per cent of the run-off (excluding the 10 per cent seasonal run-off during the monsoon) is better regulated and spread out over the year. This has been crucial in reviving the Arvari. If this run-off had not been regulated, the river would not flow throughout the year. This shows how fragile the ecosystem is.

source: http://www.tarunbharatsangh.org/dark%20zone%20to%20flow.html