Finding Groundwater

This presentation by ACWADAM deals with hydrologic properties of the rock framework in which groundwater occurs and through which it moves. In watershed programmes, it is necessary to develop a correct understanding of the storage and transmission of water within such channels because the shape of openings in a rock or sediment, their size, volume and interconnection play a vital part in the hydraulic characteristics of an aquifer.

This presentation by ACWADAM deals with introducing groundwater management protocols for wells in different phases of groundwater use. These protocols include geo-hydrology in watershed development, protection of recharge areas, efficient well use, pump capacity regulation, distance with respect to drinking water well regulation, depth regulation in drinking water well, regulation of agricultural water use and groundwater management through sharing.

This presentation by ACWADAM explains the occurrence of groundwater and deals with the vertical distribution of groundwater. To begin with, the openings in rocks in the zone of rock fracture such as intergranular openings, vesicles in volcanic rock, joints & fractures and solution cavities are described.

This presentation by ACWADAM deals with the three basic types of rocks that are found in nature – igneous, sedimentary and metamorphic. Rocks are classified on the basis of minerals & chemical composition, by texture and by the processes that formed them.

This presentation by ACWADAM on hydraulic conductivity deals with the hydrologic properties of rocks that signify the status of a rock as a good or poor aquifer. The status of a rock with regard to groundwater occurrence and movement is decided by its porosity (specific yield, more practically) and its hydraulic conductivity. These properties decide whether a rock can store and transmit groundwater.

Hydraulic conductivity is also commonly called as permeability of the rock or rock material and is its ability to allow the flow of groundwater through it. A rock with good hydraulic conductivity allows groundwater to easily flow through it.  

The presentation describes Darcy’s Apparatus, which comprises of a glass cylinder filled with porous sand. The glass cylinder with the sand bed had an inlet for inflow of water and an outlet for outflow of water. Two vertical glass tubes (manometers) are fitted in the sand tube placed at a fixed distance from each other to measure the respective levels (hydraulic heads).

This presentation by ACWADAM deals with Karst hydrogeology, a term used to denote the topography over limestones, dolomites or gypsum rich rocks where there are sinkholes, caverns and lack of surface streams. Karst mainly refers to carbonate rocks: Limestones (CaCO3) or Dolomites (MgCa[CO]).

The formation of carbonate rocks can be traced to physical and chemical deposition. Physical deposition is clastic in nature formed by deposition of particles carried in suspension. It is marked by higher primary porosity and low secondary porosity. Chemical deposition is in the form of precipitate formed by deposition of particles from solution. Contrary to physical deposition it is marked by low primary porosity and high secondary porosity.

This presentation by ACWADAM deals with springs, their characteristics and types. Springs are indicated by locations or points on the ground surface, where water from beneath the ground emerges on to the surface. A common example is of an overflowing unconfined aquifer.

Some of the characteristics of springs are:

• Discharge from spring may be constant or variable.
• Springs can be perennial or seasonal.
• Discharge from a spring may vary between from a trickle to about 100 cum per second.
• Difficulty in access.
• Variation in discharge.
• Temperature of spring water may vary from mean atmospheric temperature to lower or higher, even boiling temperatures. Hot quality water springs are common to many parts of the world.

The presentation by ACWADAM deals with a case study of augmenting groundwater resources by artificial recharge in Kolwan valley, Mulshi taluka, Pune. The DfID funded project was undertaken by the British Geological Survey in collaboration with its partners in India from 2002–2005. The objectives of the study were:

• Improved knowledge of the impacts of managed aquifer recharge in different physical and socio-economic settings.
• Guidance on scope and effectiveness of managed aquifer recharge for implementers, funders and policy makers.
• Dissemination of knowledge.

The presentation by ACWADAM is part of the training module developed by them on “Planning, development and management of groundwater with special reference to watershed management programmes”. Pumping a well and observing the effect of such pumping on the water level in the pumped well as well as in the adjoining parts of the aquifer through observation wells is the basic procedure involved in a pumping test.

The paper by International Water Management Institute (IWMI), Challenge Programme for Water and Food (CPWF) and University of Arizona deals with energy supply and expansion of groundwater irrigation in the Indus-Ganges basin. Irrigation using groundwater has expanded rapidly in South Asia since the inception of the Green Revolution in the 1970s and it represents the largest source of irrigation in the basin.