Revitalization of Rivers in India Draft Policy - Isha Guru Jaggi Vasudev

Revitalization of Rivers In India
Draft Policy Recommendation
EFFECT OF AFFORESTATION ON GROUNDWATER AND
SUBSURFACE RUNOFF TO RIVERS
Developing tree cover by tree plantation in the runoff and floodplain
area of rivers is a very simple and effective solution to ensure prolonged
surface and subsurface flows, and enhance overall water supply.
Trees through their roots enhance the percolation of the water from
condensation and percolation into the soil. This will lead to an increased
quantum of water in groundwater aquifers that feeds into the flows of the
river. Trees help the soil to feed water flow into the rivers in a consistent
manner over a long period, drop by drop through its groundwater.
Where does the water in a river come from when it has not rained
recently? Base flow is the technical name for flow in a stream or river.
River base flow results from groundwater seeping into riverbanks or the
riverbed. Base flow is the sole or primary source of streamflow during the
annual dry season when rainfall is insufficient to generate substantive
runoff. The groundwater flow has a much larger scale and is controlled by
vegetative cover, rainfall, land-surface slope, geology and other factors. 31
Hydro-geologists have recognized the importance of the interconnected
nature of groundwater and surface water. The surface water is almost
always connected to groundwater, which has a critical impact on river
water flow.
In general the base flow can be significant enough to allow the
stream to flow around the year (i.e. perennial or permanent stream).
Recharge from groundwater through base flow is the major source for
sustained flow in the river except during storms. For example, on average,
40 percent of all flow in United States rivers and streams originates from
the groundwater. Groundwater flowing into a stream is called a “gaining
stream”, the most common occurrence of water inflow to streams.
Contrariwise, when a river level gets a rise, for example in response to a
storm, water can flow from the river into the channel banks, as the water
level in the channel rises above the pre-storm groundwater level. This
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