Groundwater

This report by ACWADAM is a synopsis of the hydrogeological study carried out for BIRD-K in Pavagada, Sira and Bagepalli areas of Tumkur District, Karnataka. The study aimed at an impact analysis of recharge through borewells as well as suggesting new sites for the same.

The principle objectives of the study were:

•  Impact analysis of aquifer recharge through borewells done by BIRD-K in Pavagada and Sira Clusters
• Suggest new sites for aquifer recharge through borewells in Bagepalli cluster.

The methodology used a background study of the area through images from Google Earth. A detailed geological fieldwork in the area was carried out. Various structural and hydrogeological measurements were made to map out the aquifer systems within the area. Water levels in borewells and dug wells were measured. The study area included seven watersheds and falls in two clusters namely Pavagada and Sira. Both these clusters are located in the Tumkur district of Karnataka.

This presentation by ACWADAM on community organization in groundwater management deals with the processes involved in people’s mobilization and participation. The requisites of groundwater management include: resource enhancement, demand management, equitable distribution, institutional mechanism and controlling of free riding. It deals with groundwater management at a local scale when compared to aquifer management.

Aquifer management involves:

• Identification of aquifer on the basis of geology;
• Identification of recharge and discharge areas;
• Assessment of aquifer capacity and yield through aquifer mapping;
• Protection of recharge area and increasing the groundwater level through artificial recharge in recharge area (based on the geology);
• Treating groundwater as a common property resource;
• Encouraging community use of groundwater and restricting individual use;
• Putting in place an institutional mechanism and legal back up for community groundwater management;
• Awareness generation regarding groundwater and science of hydrogeology.

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 Pani Panchayats as a model of groundwater management.

Pani Panchayat is the name first given to a movement by Mr. Vilasrao Salunke for motivating farmers of Naigaon village of the drought-prone Purandhar taluka of Maharashtra in 1974. The government's inability to deal with the drought situation prompted him to take a 40 acre land on lease from the village temple trust and develop a recharge pond in the recharge area of the village, a dug well in the discharge zone and a lift irrigation system.

Farmers got impressed with the results demanding a scale up of the experiment leading to the setting up of Gram Gaurav Pratisthan (GGP) through which the work was expanded to encompass both groundwater and surface water management. 

The presentation by ACWADAM deals with measurement of weather parameters and outlines the methods used in weather related data collection and analysis. Weather information is necessary for the planning and implementation of watershed programmes, especially in understanding factors like groundwater recharge, the relationship between recharge & discharge and in aspects like irrigation planning.

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.