Costantino Faillace<cfaillace@hotmail.com>

The main areas covered by the paper are located in some of the counties of PuneDistrict and in the northern counties of Thane District, in the western Deccan volcanic province of India.

Index Map of the areas covered by the paper

90% of Maharashtra State is covered by Late Cretaceous and Early Eocene volcanic rocks, characterised by a thick sequence of multi-layered lava flows, including hard, compact basalt (Deccan Trap), often crossed by dykes and sills and intersected by deep faults. Its thickness is around 2000 meters in the Bombay (Mumbai) area.

The Ghat (Hilly) belt is characterized by a number of different morphological conditions, including impressive cliffs incising and dissecting the escarpments as shown in the picture that follows. Morphology along the coastal belt varies from flat to gently undulated.

Deccan Trap multilayered volcanic rocks at Kandhala escarpment

Dekkan Trap – Ghat, Kandhalaescarpment

Thick, compact andimpervious basalt

Multilayered volcanic sequence of hard and softer outcrops

Sequence of hard, solid basalt and softer volcanic strata

GROUNDWATER IN BASALTThe most promising groundwater conditions are in depressions, stream banks and inter-lava flows or in areas where basalt is intersected by dykes, and wherever the rock is deeply weathered or highly fractured.

The groundwater quality is generally good with rather low values of total dissolved solids, hardness, salinity and chloride content; in most cases is suitable for

domestic and irrigational use.

- Several studies have been carried out in Maharashtra State to assess the hydrogeological importance of the Deccan Trap sequence. -The intensive groundwater development of the past decades including hydro-fracturing and borehole blasting helped to increase the storage capacity of fractured basalt. -Groundwater availability, thanks to intensive drilling, has surely alleviated the widespread poverty of hundreds of millions of rural people, thus contributing to the success of the “green revolution”.

-In the past twenty years much attention has been paid to drought-prone semi-arid areas by introducing appropriate technology for watershed management.

- Groundwater availability has increased in many places by numerous percolation tanks and other water-holding structures to recharge ephemeral aquifers.

-Trials have been carried out to increase water storage capacity of poorly fractured rocks by creating an ‘artificial aquifer’ by drilling and blasting in a number of shallow bores located around large diameter open wells used for irrigation or domestic purposes.

- Thanks to such efforts, low- yielding boreholes and seasonal open hand- dug wells located in hard rock terrain are now supplying permanent water for human consumption and for irrigation of cash crops.

The Tribal Village Water Program (TVWP)- This program is the author’s self financed project. It started in Pune District in 1989 and consists in drilling boreholes for small villages, especially those which have never received any protected water source from the government or other institutions, where people still where drinking highly polluted water. -In 1994, following a cholera epidemic in the Northern Thana District that caused the death of 1500 children, the program was moved to the affected area, located between 100 and 170 km north of Mumbay.-Altogether more than 350 new boreholes have been drilled in Pune and Thane districts of Maharashtra State and 250 abandoned boreholes repaired.

-The project provides safe drinking water to the Adivasi (Tribal) communities, considered to be the “poorest of the poor” of rural India;

It also promotes an appropriate pumping technology by means of the low cost “bucket pump” manufactured and maintained locally and installed in remote villages and hamlets.

People’s ParticipationVillagers participate with enthusiasm in the

well construction by offering their labour, collecting local material (sand, gravel and stones), purchasing bricks and, when possible, 3-4 sacks of cement.

Their contribution is essential for making the program sustainable, as users will then be more responsible for the operation and maintenance of the wells.

The drilling success rate has been between 85% and 95% in the first years, decreasing slightly in recent years as the most promising sites had already been selected in previous years.

Selection of the Villages and Drilling Activities

The selected villages have a population ranging from 50 to 450 people. Highest priority is given to those villages where no drilled or hand-dug wells exist and people collect water from unprotected, rudimentarily dug open holes, generally located in river beds and depressions.

Water from these rudimentary holes is very unsafe for people and animals.

Groundwater conditions

Aquifers are generally shallow, represented by weathered and fractured basalt located mainly in depressions, river sides and flat areas. Deeper aquifers may also occur. They are, in most cases, represented by inter-lava flow materials; exceptionally by granular rock types. Some prospects to find groundwater is also along fault lines and dykes.

- Groundwater in shallow aquifers of the project area is under phreatic conditions while in deep water-bearing layers it may be under semi-artesian conditions.

- Water quality is generally good, usually with TDS exceptionally exceeding 500 mg/l. Much higher values are met in water wells along the coast where seawater intrusion may occur.

A new Mark II equipped well for this large Adivasi Community

Artesian wellIn exceptional cases groundwater can be found under artesian conditions at relatively shallow depths, like in this newly drilled borehole.

SHIVA LINGAM WELLThe previous flowing wells, just upon completion of the installation simulating Shiva Lingam, the sacred symbol of creation, venerated by the Hindus.

A Newly drilled artesian well

Ganeshpuri – A new thermal water well

Thermal spring water - Flowing hot water occurs in several places along the coast, connected with dolerite dykes or faults

Akloli – One of the overcrowded thermal water “kunds”

TVWP - Drilling results

The average yield of boreholes drilled by the project in volcanic rocks of Maharashtra is in the order of 1,500 litres per hour; in a few cases borehole yield exceeds 10,000 l/hr.

Drilling is carried out by a contractor using down-the-hole hammer drilling. Casing is inserted only in the soft and weathered rock.

Drilling machine used by the TVWP

KUPRI WAG PADA BOREHOLE (20000 litres/hour)

As most boreholes struck water within the first 100 feet, it was found more appropriate to drill, for the same village, two boreholes of 120 feet each rather than to insist on going deeper in a dry hole and reach 240 feet, as is usually done by other organisations; such a depth may be justified in areas where previous drillings have proved the existence of a deep aquifer.

It is government practice to install the hand pump cylinder not deeper than 120 ft; therefore, the section below this depth would not contribute to increase the pumping rate unless water would be under artesian or semi-artesian conditions.

The Bucket PumpThe bucket pump is a simple

water-lifting device designed by the author in 1994 mainly for low-yielding boreholes; not appropriate for the installation of Mark II and Mark III pumps, widely used in Maharashtra.

The main concern in designing the bucket pump was to keep it as simple as possible in order to minimise maintenance problems (all mechanical parts were excluded). Altogether more than 150 bucket pumps have been installed in the past fifteen years.

THE BUCKET PUMP has four components: the pump stand, the windlass with handle, a 5 litre cylinder with a foot valve, and a wire-rope; the platform completes the installation with the adjacent little temple.

Bucket Pump Performance

The bucket pump was originally conceived for low-yielding boreholes. Subsequently, its use was extended to boreholes drilled in remote villages, specially those not accessible during the wet season for the maintenance of other types of pumps.

- Poor yielding boreholes (less that 500 litres per hour), with water levels between 20 and 30 ft can supply 150-200 litres per hour.- Boreholes with good yield (between 500 and 1,000 litres per hour) and water levels around 30 ft may supply 300-400 litres per hour. - High yielding boreholes (more than 1,000 litres per hour) with water levels around 15 ft may supply up to 800 litres per hour.

The yield of 150 boreholes equipped with bucket pumps ranges between 25 and 42,000 litres per hour. The use of the bucket pump in high-yielding boreholes was justified by the small size of the villages, or by the possibility to replace the bucket pump at the end of the wet season with an submersible electrical pump for irrigation during the dry months.

A Small Temple

A miniature temple is constructed adjacent to the platform of each well so that the site, in addition to supplying safe water, becomes also a place of worship. A little statue of a Deity selected by villagers is installed inside the little temple in devotion and gratitude towards God for the blessings received for having found safe water. Preference is generally given to the Elephant-Headed God (Lord Ganesh), believed to be the remover of obstacles.

The Pooja CeremonyUpon completion of the pump installation in each of the successful boreholes, Pooja is performed in front of the little temple by a lady who volunteers or one selected by villagers. Garlands, Kum-kum (holy red powder), Incense sticks and Coconuts are used during the ceremony while people sing bhajans(Prayers).Pooja creates an intense moment of happiness for the participants.

POOJA for a newly constructed well in Ganeshpuri

Conclusions

- People will actively participate in a water program offering labour and local material, and also a small amount of cash for pump maintenance if the new water source belongs to them. In this case it is their responsibility to take good care of it.

- The site selection should be done with the people’s participation and approval and should, as much as possible, satisfy the women.

-People’s awareness on the importance of drinking clean, safe water and by keeping the newly created water source free from pollution, helps reduce water-borne diseases.

- It is therefore necessary to explain, specially to women and children, the importance of hygienic measures to be taken in order to prevent water contamination.

-Simple, low-cost technology, appropriate to people and local conditions, contributes to reduce pump maintenance and dependency on outside help.-Pump maintenance will be easily carried out by beneficiaries if villages are located in developed areas. Villages located in remote areas, instead, will have difficulty in keeping their water wells in working conditions. Bucket-pump is very useful in such villages as it needs minimum maintenance.

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