Rainfall and other forms of Precipitation

The Eleventh Plan (2007-08 to 2011-12) sought to build on the gains achieved in the Tenth Plan and shift the economy to a path of faster and more inclusive growth. The Mid Term Appraisal (MTA) report for the Eleventh Five Year Plan 2007-2012  by the Planning Commission reviews the experience in the first three years of the Plan and seeks to identify areas where corrective steps may be needed.

This presentation by ACWADAM deals with groundwater typologies in India. The typology of groundwater can be defined in many ways based on a) Uses of Groundwater, b) Geography, c) Geology, d) Hydrogeology (Aquifers), e) Groundwater Quality, f) Stage of Groundwater Development, and g) Socio-ecology of Groundwater.

This presentation by ACWADAM deals with the subject of groundwater balance. It begins by describing the skeleton for the water balance equation viz., ground surface, soil, aquifer and bed rock. It describes the processes subsequent to rainfall such as interception, initial detention, depression storage, infiltration, runoff, streamflow, soil moisture retention and recharge.

The watershed water balance equation is explained in terms of input (rainfall and water transfers) and output (runoff, evapotranspiration and infiltration). It notes that the input to a generalized water balance is rainfall whereas the input to a groundwater balance is infiltration. The difference between infiltration & recharge, natural & artificial recharge and interflow & discharge are explained thereafter. The water balance for an aquifer may vary, depending upon the nature of groundwater system –

• Watershed with a deep aquifer
• Watershed has both shallow and deep aquifers
• Watershed has only shallow aquifer

Floods, rains, droughts

There have been reports of flooding as well as incessant rains in the northern parts of India such as Delhi, Punjab, Haryana, Chandigarh, Uttar Pradesh, Rajasthan as well as the northeast such as Assam, Arunachal Pradesh. At the same time, reports indicate that parts of Madhya Pradesh have been facing severe drought while parts of Himachal Pradesh indicate sudden drops in temperature with reports of snowfall in certain areas. Reports from  West Bengal also indicate extensive flooding in certain parts of the state.

Waterbodies/ Rivers

• Dams on the Himalayas: Environmentalists demand scrapping of projects in Assam, Manipur and Arunachal Pradesh
• Involve people to conserve Himalayas, stop big dams: Environmentalists argue
• Uttarakhand government halts work on a hydel project: priests and devotees resist the submergence of a temple