New technologies for ground water

Code No: TMS110 Price:Rs1800/- Category: Water 

 

The role of ground water to meet the demand of water in agricultural, industrial and domestic sector is progressively increasing. Although, India has substantial ground water resource availability, its scientific management is necessary, both in the short term and long term perspective. The wide diversity of geological structure in the country calls for a combination of techniques to identify potential ground water resources, assess their potential, draw/abstract the water prudently and manage both, its quantity and quality in the long term. The technology in the field of ground water has rapidly progressed in the past decade and application f new techniques could benefit Indian in managing this vital resource effectively and efficiently. In this context, a techno-market survey on New Technologies for Ground Water has been commissioned. A summary of the survey is presented below:

1. Scope and Coverage

The scope and objective of the study is to address the following aspects in the context of the above mentioned topic of the survey.

a) Relationship and the importance of the specific topic to the broad area to which it belongs (in brief).

b) The current status of the technology in the world and in the country. Market (domestic /export) sizes and their potentials.

c) Assessment of the technology, resource parameters such as energy, raw material, infrastructure and manpower etc. to arrive at preferred technology options available to the country.

d) Short term and long term economic aspects preferred options along with their feasibilities.

e) Impact of the preferred option(s) by itself and its spin offs.

f) Recommendations:

* For implementations of preferred technology option(s) indicating critical inputs such as raw material, capital goods and human resources required and their availability, investments required to commercialize, and benefits/returns expected. Maximum possible quantification is required.

* For R&D / Technology development indicating the requirement of inputs and expected benefits.

g) Action Plan for implementation of recommendations alongwith identification of:

* List of available technologies for Indian industry and
* The agencies/groups/individuals for implementation.

h) Expected impact of recommendations, if implemented.

2. Methodology

The methodology adopted comprised the following steps:

A. Desk Research: Thorough search and review of published literature in related field from various books, periodicals, published papers, journals on the subject was conducted. The books and periodicals are listed under ‘References’ and ‘Bibliography’.

B. Data Search: Review of data through various agencies including electronic media was carried out to collect the latest information on the subject.

C. Primary Research: Both structured and open ended questionnaires were sent to leading institutes, organizations and consultants to solicit their views on different issues. Annexure I summaries the findings from the primary survey conducted. List of Organizations / agencies/Govt. Bodies and Foreign Bodies contacted are also been given in an enclosure as also the details of those who responded.

The information & data so collected were analysed and inferences, conclusions drawn. Recommendations and action plan were formulated based on the findings of the survey.

3. Highlights of the Survey

Summary of the findings of the survey are as follows:

1) Increasing requirements of water is leading to higher requirement of ground water. In India, the share of ground water to meet the total demand of water is likely to increase. Ground water is a renewable but limited resource. The water in the underground aquifer gets recharged by rain water, canal seepage, irrigation water infiltrating through different layers of soils. If the rate pf abstraction of ground water is higher than the recharge rate, the water level of the aquifer recedes. India has substantial ground water resources but the development is not uniform, through out the country emphasizing the need for planned development and scientific management of this resource.

The technology related to various areas of ground water management namely exploration, assessment, abstraction, recharge, pollution and salinity control has advanced in the past decade. Considering the wide variation in the geological forms in India, usage of a combination of techniques is necessary. Adoption of new techniques in the above mentioned areas have to be planned considering their suitability to Indian conditions.

2) The first activity for ground water development is to locate potential aquifer. Since the water is beneath the surface, task of locating it successfully is complicated. The prospecting is initiated by geological field reconnaissance combined with desk research of available geological records/maps and data.

Remote sensing technique has provided an effective tool for expeditious survey of the identified area to pinpoint features which control the development, occurrence, storage and flow of ground water. The technique uses aerial photographs as well as satellite imageries along with software support for enhancement of digital data, easier analysis and image classification. National Remote Sensing Agency, Hyderabad, is the nodal agency providing satellite data received from various satellites, namely IRS 1A/1B (India); LANDSAT (USA) and SPOT (France). Different wavelengths and brands are used for imageries; infra-red being most useful for ground water exploration.

The digital data is analysed with the help of computers and powerful software support to delineate potential areas with high probability of ground water. New method uses the imageries based on reflectance of a waveform emitted by transmitter mounted on aircraft (Side Looking Airborne Radar – SLAR). Apart from capability to maintain uniform intensity from transmitter, this method gives more details of landform due to low angle of incidence.

Airborne magnetic/electro magnetic survey technique is useful in areas where penetration of the top surface of earth is required e.g. in deserts covered with sand.

Remote sensing technique is useful for preliminary survey to delineate ground water prospective zones. In comparison to old techniques of water prospecting, it can save time, effort and money, if large area is to be explored.

3) The primary identification of prospective water bearing area is followed by geophysical surface investigation techniques. The major techniques are:

a) Seismic technique – Refraction and high resolution reflection technique, b) Resistively technique, c) Induced polarization technique, d) Magnetic technique, e) Gravity technique, f) Electromagnetic technique slingram system and VLF system.
The electrical resistivity and seismic techniques are most commonly used for ground water exploration. Other techniques are employed to supplement specific information needs that cannot be achieved by the above methods of to enhance the details of the hydro-geological formation indicated. Resistivity technique is the cheapest and its equipment is available indigenously.

The electro-magnetic technique is faster and more suited when the surface layer has a sufficiently high resistivity, but is severely limited by presence of underground material like power lines, cables, pipes etc. having electromagnetic property.

4) The geophysical survey technique helps in pinpointing the site for test drilling. During test drilling, samples at regular intervals are taken to form drillers log to get details of stratigraphy of the drill hole. Various other logs are conducted to get more details about the aquifer characteristics and the hydro-geological details like porosity, permeability, transmissivity, storativity etc. the different logging techniques that are used are:

* Resistivity log
* Spontaneous Potential log
* Radio Active log
* Temperature log
* Caliper log
* Fluid Conductivity and fluid velocity log
* Induction log
* Sonic log
* Close circuit television log
* Environmental Isotope log.

The most commonly used log is resistivity log. Most of the logs can be used in uncased bore holes only, except for radio active log. Depending on the hydro-geological information suitable logging technique can be used (Table 2.2).

5) Consequent to a successful test bore hole development, the quantitative assessment of its yield, storativity, recharge and other parameters is necessary to evolve a pragmatic water abstraction strategy. Norms fixed by Ground Water Estimation Committee (GEC) are presently used to estimate ground water potential. Ground water level fluctuation method and pumping test are the most commonly used method to determine the yield of the well and aquifer parameters. Other methods are Water Budget Study and Recharge Estimation by River Hydrograph.

Ground water level fluctuation method is quite simple and fastest, but in case of non uniform aquifers it can lead to erroneous results. It is not applicable for confined aquifers. Pumping test is the practical method for determining yield though time consuming. The yield of aquifer may be difficult to determine if it is too large with respect to well undergoing the pumping test.

GEC norms though simple, are based on number of assumptions that may not be true at different locations, mathematical modeling is the new technique that can be used for various purposes in addition to assessment of the aquifer parameters. With the help of computers and modern software, this method holds promise for application in lot of areas related to ground water.

6) The abstraction of water from the aquifer requires construction of suitable well structure. Different techniques of drilling that are used ofr sinking a well are:

- Percussion or Cable-tool Technique (open hole or cased hole): Latest version of Percussion technique is Open Hole Drilling-down to 300 m.
- Direct Circulation Rotary Technique
- Reverse Circulation Rotary Technique
- Down the Hole Hammer Technique

In unconsolidated formations, rotary drilling technique is most commonly used. Direct circulation technique is normally preferred. It can drill to large depths. In a site having boulders percussion technique is applied. In rock formulations / consolidated formation, down the hole hammer technique is bet suited.

7) Well design is governed by various factors like output required, yield of the aquifer, stratigraphic details of the aquifer and overlying sediments, cost of construction, grain size of unconsolidated aquifer materials etc. Casing diameter is determined by the size of pump and the velocity of water in the well. Quality of water is a major factor to decide material other than cost. Variety of material can be used like steel, SS 304/316, PVC, Fibre glass, HDPE, HDPP etc.

Most bore wells require pumping equipment unless under artesian pressure. Most commonly used pump is centrifugal type. Different configurations are used depending on source of power, discharge rate, discharge head, yield of the well. Various types of centrifugal pump etc.

* Surface mounted Horizontal Pump
* Vertical Turbine type pump with electric motor/diesel engine drive
* Submersible Pump
* Jet Pump
* Airlift Pump

Use of Helical Rotor type of pump is reported from countries like Australia, New Zealand, Israel, African Countries in different designs as follows:

* Horizontal mounted
* Vertical mounted submerged pump with Drive at Ground Level
* Submersible Pump

For high discharge rates, centrifugal pumps offer better efficiency. There are numerous manufacturers of different types of Centrifugal Pump designs in India. Jet pumps are used in domestic segment in wells deeper than 25 feet, having low discharge rate. For high discharge heads coupled with low/medium yield of well, Helical Rotor Pump is reported to offer good efficiency apart from flexibility of matching output to change in yield due to seasonal variation.

Manufacturers of helical rotor pump in India have horizontal pump in standard range. For vertical models, with drive arrangement at ground, designs are available and select sizes are manufactured. For submersible designs, low rpm submersible motors are technology bottleneck area in India.

8) The ground water is recharged naturally by monsoon water percolating down through soil. However, heavy abstraction rates exceeding the recharge rate would deplete the resource in the long run. Strategy options for ground water management are either to stop over exploitation or augment the resource. Present administrative measures for controlling over exploitation are selective and suitable legislative support is required combined with implementation. However, greater awareness and mass participation for prudent use of the resource are essential.

Artificial Recharge Technique is useful for increasing the volume of water recharged to the ground water system. Three major techniques of artificial recharge are:

* Spreading Technique
* Induced Recharge Technique
* Injection Technique

In spreading technique, numerous methods have been developed, viz. Flooding Method, Basin Method, Pit Method, Channel Method, Ditch/Furrow Method & Irrigation Method. Depending on the source of water to be used for recharge, local hydro-geological details for the aquifer to be recharged, rate of recharge etc., suitable technique may be used.

Injection technique requires high quality of water for direct recharge into the aquifer through recharge wells. It may be necessary to recharge under pressure to avoid entry of air bubbles. Induced recharge technique is actually acceleration of water percolation through the soil by increased withdrawal and creation of hydraulic pressure gradient.

Clogging of the pores in recharge wells is a common problem in recharging process. This requires provision of settling area to separate out suspended solids. For clogging due to microbial activity, treatment of water before recharge is done in Injection technique. In Spreading technique, periodic cycles of recharging, drying and tilling of the tank/reservoir bottom is required.

Waste water is used for recharging by Soil Aquifer Treatment (SAT) Technique. The rapid loss of microbial activity below the surface of earth and the filtering capability of soil are used to advantage in this type of method. Different techniques of SAT are:

* Bank Filtration
* Surface Water Recovery
* Underground Drain Recovery
* Well Recovery.

Problems associated with this technique are similar but more pronounced as in Spreading technique since the quality of water is much inferior. Algae growth clogs the filter and further the high carbon dioxide content leads to precipitation of calcium carbonate, further compounding the clogging problem.

Spreading technique requires vast area of land and loss of recharge water due to evaporation in high. This is the closest to natural recharge by rain water in monsoon. Injection technique does not require vast land areas and is quick in rate of recharging. This is the only technique for recharging where overburden has very poor permeability for confined aquifers.

9) Sub-surface drainage leads to loss of ground water over period of time. Techniques like Underground Bandharas, Sub-surface dykes/dams and Fracture Sealing Cementation are used to prevent thus drainage. Suitability of the techniques is governed by certain site conditions that allow construction of such structures. Though these techniques are not in the nature of recharging water, they nevertheless help in augmenting the water resource by conserving drainage loss.

Other techniques for augmentation of ground water are aquifer modification techniques viz. Bore Blasting and Hydro fracturing. In the case of Bore blasting, high pressure waves formed due to explosion, are used for enlarging aquifer storage area as well as develop fractures that would ease recharge. In hydro fracturing, high water pressure is used to create deep penetrating vertical fracture that would improve yield and productivity of the well.

In India, different techniques have been tried out. The detailed cost analysis is not available but it is noted hat the cost varies depending on different factors related to recharge project. The spreading technique is the cheapest if vast tracts of land are available as it can also use inferior quality water for recharge. Other augmentation techniques are costlier involving civil construction and other miscellaneous costs.

The economic viability of any augmentation project has to take into account the social and other intangible benefits. The cost benefit analysis cannot be generalized and has to be project specific.

10) The management of ground water also requires quality maintenance in addition to quantity. There are several sources of pollution from agricultural, industrial and domestic origin that have led to pollution of ground water in various states in India. Assessment and monitoring of pollution is done by analysis of sample from observation wells.

The major pollution is different parts of the country is of fluoride, nitrate, arsenic, heave metals and sulphate ions. In industrial belts, pollution due to effluent is notices. Complete survey of all ground water resources has not been done but all the work done so far has been complied by CGWB, ground Water Pollution Directorate, Lucknow.

Potential pollution sources on the surface are identifiable using remote sensing/ aerial photography technique combined with GIS and computer support. For quick analysis and identification of chemical pollution in ground water sample, a number of sophisticated equipments are use. New instruments are more reliable and of higher accuracies.

11) Prevention of pollution is the best alternative. The pollutant takes long time to reach ground water and once having reached the residence time is long. Different prevention techniques are:

Agricultural Source:

* Use of crops in sequence to maintain soil salt balance.
* Use of organic manures / optimum quantity of chemical fertilizers
* Use of integrated pest management technique to avoid excessive use of pesticide.
* Optimal irrigation and use of purified sewage for irrigation.

Municipal & industrial Source:

* Zoning for locating point source of pollution away from recharge areas.
* Treatment before discharge.
* Recycling/reuse of water.
* Liners or impervious bottom and side walls for septic tanks, buried storage tanks, cess pools and landfill areas.

12) In the event of pollution having taken place, the option is to contain its movement to other parts of aquifer and prevent further damage. Blocking the containment plume or removal of the plume are two technology options however, these techniques do no correct the problem totally.

a. Remedial techniques are of two types:
b. Pump and treat
c. In situ remediation

Soil aquifer treatment technique may be used under the pump and treat option for suspended impurities and microbial pollution. For dissolved solids, other techniques are needed to be used like:

* Chlorination at source for bacterial pollution treatment
* Mobile bio filtration.
* Two phase Extraction Technique for volatile pollutant
* Granulated Activated Carbon Technique

In-situ techniques are

a. Soil Vapour Extraction
b. Bioremediation

In India, presently only assessment of pollution fro ground water has been initiated by various agencies. No techniques for prevention/ containment or remediation have been used.

13) In many areas the ground water is saline. In some areas, the salinity is due to natural causes as a result of dissolution of solids from surrounding rock formulation into aquifer. Some parts of Rajasthan and Gujarat have brackish water. Other cause of inland salinity is water logging due to over irrigation or seepage and return flow of irrigation with dissolved salts from fertilizers and other soil amendments. Heavy withdrawal also leads to upcoming of saline water from the lower portion of aquifers containing saline water. Several districts in Punjab and Haryana are having inland salinity due to these reasons.

In costal areas, sea water intrusion is the primary cause of salinity ingress in fresh water aquifers. Gujarat, West Bengal, Tamilnadu, Andhra Pradesh are some of the states facing the problem of inward movement of sea water/ fresh water interface.

14) Remedial technique for salinity of ground water can be classified in Management Techniques, Recharge technique and Salinity Control Techniques. Management techniques are:

a. Cropping pattern that can withstand saline water.
b. Regulating and controlling ground water extraction and
c. Usage of mix of saline water and sweet water.

Recharge technique in inland salinity cases is aimed at i) dilution of salt concentration to make water fit for usage and ii) creating a fresh water pressure gradient so that upconign of saline water is prevented and a top layer of good water is formed.

In case of costal aquifers, recharging is primarily done to increase fresh water pressure and push back the sea water intrusion. Other techniques for costal aquifer salinity control are:

i) Tidal Regulators and Bandharas
ii) Static Barriers
iii) Fresh Water Barrier
iv) Extraction barrier

Some of these techniques have been tried out in Saurashtra region in Gujarat. For drinking water needs from aquifers where top portion is sweet and bottom part if saline, one of the technology option is to use skimming wells m employing controlled withdrawal of sweet water from top layer only. For higher volumes of withdrawal, that may cause upcooning of the saline water, Scavenging well technique is useful in which fresh water and saline water are simultaneously abstracted in a manner such that the fresh water-saline waster interface line is not disturbed. Apart from these, the only other option for utilizing saline ground water from drinking purpose is to pump and resort to desalination to get water for desired quality.

4. Recommendation and Action Plan

4.1 Survey and Exploration

4.1.1 Widespread use of remote sensing/aerial photography technique be made to identify water bearing zones, areas for artificial recharge projects, pollution hazards etc. the region earmarked by such study should be investigated in detail by follow up surface geophysical exploration techniques like Resistively/Seismic (Refraction and High Resolution Reflection method)/ Electromagnetic Survey for complete data collection on the hydro-geology of the terrain in the area earmarked.

Central Ground Water Board (CGWB) can take the lead role in co-ordination with other agencies like NRSA, State Ground Water Boards, Pollution Control Boards etc. A database of the detailed investigation can be made for reference by various agencies in future.

4.1.2 For developing manpower resource I the filed of remote sensing, training/educational programmes be initiated in more institutes with foreign collaboration for learning the latest developments in this fast developing technology.

The content, methodology and place for training can be decided by joint effort of Indian Institute of Remote Sensing, CGWB, Ministry of Water Resources and State Ground Water Boards.

4.1.3 For remote desert areas, airborne electromagnetic surveys may be carried out to identify potential ground water region. It should be followed by detailed geophysical survey for locating site for test drilling. Electromagnetic surface survey technique (VLF System) can also be used in this area owing to high resistively of top soil layer – dry sand.

CGWB, Western Region-Jaipur is already planning to undertake this survey with the help of Geological Survey of India, which is having requisite equipment to carry out the survey. The area in Rann of Kutch I Gujarat, may also be investigated later based on experiences in Rajasthan.

4.1.4 Isotope log be used to determine infiltration rate for recharge projects and for determining velocity and direction of flow of ground water, particularly where pollution of aquifer has been noticed to decide suitable strategy for further damage to the aquifer and other remedial action.

Central Ground Water Board/State Ground Water Boards can use the technique, particularly in blocks classified ‘Disk” to determine rate of infiltration – an important data for recharge project. The pollution directorate can initiate studies of aquifers known to have pollution so that data on velocity and flow direction can be used either in evolving strategy for preventing further damage or predictive modeling to warn other users of likelihood of pollution in advance.

4.1.5 Selective use of closed circuit television log be made to investigate clogged recharge wells in Injection Recharge projects and in case of mechanical failure/caving of the borehole during drilling. Being costly method requiring sophisticated equipment, it may be used where other methods do not yield desired results.

Ground waster departments and drilling agencies can make use of this method with the help of CGWB which has the equipment with them.

4.2 Assessment

4.2.1 The existing GEC norms for estimation of ground water should be refined to accommodate situations nearer to actual conditions. Necessary R&D that may be required to study the phenomena at different sites must be done and if need be two or three norms related to set of site conditions be developed instead of one set of norms.

CGWB should work on this in co-ordination with research/academic institutes viz. IIT/Institute of Hydrology. Help may also be taken from reknowned institutes/ research agencies/consultants abroad.

4.2.2 Use of historical data and detailed bore logging be done to determine different characteristics of the aquifer and this data should be used to develop models of the ground water system. With the help of software and computerized modeling technique, reassessment of the ground water potential be done in the country, further, these models after having proved valid based on actual observations, be used to predict the behaviour of the aquifer in different conditions to evolve and implement a pre-emptive strategy for aquifer management.

Academic institutes / research agencies should work on developing mathematical models in co-ordination with state boards.

4.2.3 The recent technique for assessing specific yield by Gravity survey method be experimental in Indian conditions to check it’s applicability for quicker estimation of this important aquifer characteristic.

R&D should be done by academic institutes/ research agencies and field trials conducted in India.

4.3 Abstraction

4.3.1 R&D for modifications in drilling technique for deeper drilling be initiated so that deeper aquifers can be tapped. Results of filed testing of the Japanese rig acquired by CGWB for drilling upto 300m using open hole technique should give useful direction for future action.

Necessary help from ONGC and OIL India Petroleum Research Institute, Dehradun, can be taken as oil exploration invariably require deep drilling. CGWB can undertake drilling of deeper boreholes to exploit deep aquifers.

4.3.2 R&D for development of centrifugal pump with better efficiency should be initiated in co-ordination with the pump industry.

Bureau of Indian Standards should co-ordinate and formulate guidelines for minimum efficiency in consultation with the pump industry through Indian Pump Manufacturers Association and the user water supply bodies.

4.3.3 For deep aquifers, with low withdrawals for small drinking water schemes, at few boreholes, helical Rotor Pump may be tried out in Submersible or Surface Drive configuration and power savings studies with alternate centrifugal pump with a view to adopt this method as a more efficient technology. Further, for low speed submersible motor required for Helical Rotor Pumps, efforts for technology development should be taken.

Experimental work for study be done by research agency/academic institute and later field trials conducted at different sites in co-ordination with pump manufacturer and actual user: Water Supply Boards/Irrigation Departments.

For development of low speed submersible motor, efforts may be taken to develop the technology indigenously in co-ordination with Indian submersible motor manufacturers or it may be sourced from outside for which an integrating study may be undertaken.

4.4 Augmentation

4.4.1 In blocks identified as ‘Dark’ and ‘Grey’, detailed investigations should be done to assess the possibility of employing artificial recharge or augmentation method to increase ground water resource. Based on such data and considering successful experience in Maharashtra and Gujarat, use of artificial recharge by spreading method utilizing surface run-off during monsoon, and in conjunction with other techniques to management monsoon run – off and surface water be broadbased in the country.

While recharge is being evaluated, possibilities of reducing the water withdrawal rate in these blocks should be simultaneously examined and implemented.

4.4.2 In case of confined aquifers in such areas, recharge by injection method should be evaluated, particularly with reference to availability of water of requisites quality for recharge and the alternative of directly using such water and reducing the abstraction of ground water ion place of recharging and then withdrawing.

State Ground Water Boards should take up such project involving village Panchayats/NGOs/District Rural Development Agency.

4.4.3 In Deccan trap and Himalayan foothills, detailed investigation should be undertaken to identify sites where sub-surface drainage is leading to loss of ground water. Suitable structure, like underground bandhara/subsurface dykes be installed after economic feasibility evaluation.

Concerned State Ground Water Boards in co-ordination with local bodies /NGO’s. Necessary help may be taken from CGWB.

4.4.4 Similarly, possibility of modifying aquifers to enhance storability or recharge passage by bore blasting or hydrofracturig can be employed after feasibility study.

Concerned State Ground Water Boards in co-ordination with local bodies/NGO’s. necessary help may be taken from CGWB.

4.4.5 Recycling of used water as a means to recharge ground water may be used employing Soil Aquifer Treatment technique near urban centres.

Normally, Water supply and Sewage disposal is handled in urban centes by the same body constituted as a board. Such projects should be installed by these boards and necessary technical support can be extended by Pollution Control Board and other consultancy organizations.

4.5 Pollution

4.5.1 A detailed survey of pollution of ground water should be conducted and nature of pollutants identified. For regular monitoring of ground water quality, proper monitoring plan be drawn defining frequency, timing, sample size, investigation method, agency responsible for monitoring etc. based on such surveys, wherever the source of pollution can be identified, immediate corrective action for eliminating pollution be taken. Similar action be initiated for identified potential hazards even if the pollution may not have reached ground water.

Directorate of Pollution for Ground Water along with State Pollution Control boards should undertake this activity.

4.5.2 Any new industry should take clearance against possibilities of ground water pollution by ensuring installation of suitable precautionary systems/equipments. For all hazardous industrial units, concept of zoning be applied, so that they are located in areas which are not recharge area for any aquifer to eliminate any chances of pollutants transferring into ground water.

Suitable legislation should be formulated by state governments and administrative responsibility entrusted to pollution control boards. Pollution control board should co-ordinate with respective stage ground water board and CGWB pollution directorate.

4.5.3 For the source of ground water, which is identified to have been polluted, a three pronged action be initiated urgently: firstly, to prevent further damage by identification of pollution source and measures to nullify it; secondly, to contain the spread of the pollution by adopting suitable containment technique depending on the nature of pollutant, aquifer condition, intensity of pollution: and thirdly, to start remedial measures for improving water quality for reclamation of he ground water resource.

Respective water abstracting and utilizing agency in conjunction with state ground water board and /or pollution control board.

4.5.4 Wherever, due to the demand of water it is essential to use water from such polluted source, Pump and Treat method be used depending on the nature and extent of pollution. Further, treatment of water may be restricted to render it suitable for industrial/other uses, while for drinking purposes, water from good quality aquifer can be used.

Respective water abstracting and utilizing agency.

4.5.5 Change in cropping patterns, irrigation and fumigation practices must be canvassed to prevent pollution and/or salinity of ground water. Use of organic fertilizers, adoption of micro-irrigation methods, biodegradable pesticides must be encouraged in this respect.

NGO’s/Village and District Development Bodies/Farmer C-operative Societies should work for creating awareness and educating the farmer.

4.6 Salinity

4.6.1 For sourcing potable water from aquifers, where salinity is due to upcoming of saline water table, technique of Skimming or Scavanger (Skimming wells are already in use in some parts) wells may be experimented to establish techno-economic feasibility vis a vis alternate means of potable water supply.

Respective water abstracting and utilizing agency.

4.6.2 As a means of conserving potable water as well as using the saline water, strategy of different timings of water supply for different end-use of water in the domestic segment may be tried out.

Respective water abstracting and utilizing agency.

4.6.3 In costal areas, emphasis should be to control pumping to avoid sea water ingress. Further, the successful experience in costal belt of Surashtra be broad based by constructing tidal regulators/barriers and bandharas, wherever hydro-geological conditions permit use of these techniques.

Respective water abstracting and utilizing agency. For sea water ingress control projects, SGWBs should undertaken the project.

4.6.4 The salinity caused due to overexploitation of ground water be countered by simultaneous adoption of controlling the withdrawal rate and use of surface run-off water as recharge by spreading technique to increase fresh water level and create an hydraulic gradient causing flow of water towards the sea in costal areas.

Respective water abstracting and utilizing agency. For sea water ingress control projects, SGWBs should undertake the project.

4.6.5 In areas, where inland salinity of ground water is existing due to natural causes, usage of saline ground water for alternate purpose should be explored and ensure if feasible. Crops having tolerance to saline water may be cultivated in such areas.

NGO’s/village and district development bodies/farmer co-operative societies should work for creating awareness and educating the farmer.

4.7 Policy, Regulation & Legislation

4.7.1 Suitable legislation should be introduced at the earliest to regulate usage of ground water and avoid it’s abuse either by overexploitation or pollution. Ground water development without the active scientific support especially by various authorities should be stopped forthwith.

State Governments and Central Government.

4.7.2 To develop trained manpower in this field, which draws on various disciplines of science and engineering, courses be introduced in various educational institutes imparting training in ground water engineering and management.

Central and/or Stage Government, academicians, Educational Institutions in consultation with CGWB and SGWB.

4.7.3 The involvement of people is essential for success of any ground water management programme, be it conservation or recharge or pollution prevention, or controlled pumpage in costal areas. Role of NGO’s and Gram Panchayat is very significant in creating awareness along with suitable mass communication support. Suitable mass awareness and contact programmes be initiated in educate the mass for using ground water resource with care and nurture it.

NGO’s/village and district development bodies/farmer co-operative societies with assistance from state and central governments.

4.7.4 A well defined water policy should be formulated for implementation which takes into account the management of all components of water sources in the country viz., surface, monsoon run-off and ground water. Conjunctive use of surface and ground water be encouraged in right proportion ensuring balanced water conditions. Surface water should be the primary source with supplementary role of ground water and effective conservation of monsoon water minimizing drainage to sea.

Ministry of Water Resources, Central Government.

4.7.5 Financial constraints are often bottlenecks in adopting expensive technology. Participation of private sector may be considered for optimal development of ground water resource and they be allowed to recover costs by charging suitably, particularly for industrial use.

SGWB/CGWB/District Development agencies under guidelines to be framed by Central/State Governments.

4.7.6 Presently, the ground water related issues fall under the purview of various agencies. The co-ordination between so many agencies having different point of view due to different responsibilities assigned, is a very complex issue. The decision making can not be only delayed but consensus also may not be there on certain issues. A separate study of this interrelation between various agencies and their impact needs to be done to evolve proper organizational set up for ground water management.

Ministry of Water Resources, Central Government.

5. Expected Benefits

There would be numerous benefits by implementation of above recommendations:

* Expeditious identification of ground water bearing regions in a sorter span of time and at a lesser cost also revealing of other useful information like, earmarking of recharge areas, identification of pollution hazards etc.

* Improve the hydro-geological data base which would help in assessing the possibility of undertaking recharge projects, formulation of mathematical models for understanding aquifer characteristic and predict behaviour to different types of abstraction and /or recharge strategy.

* Precise estimation of ground water potential of the country and utilization status.

* Development of deep drilling techniques to exploit deeper aquifers of Ganga basin of auto flowing type.

* Development of better efficiency pumps leading to enormous saving of power.

* Adoption of artificial augmentation techniques would help rejuvenate the depleted ground water resources in critical areas categorized as ‘Dark’ and ‘Grey’ blocks of the country.

* Improved availability of water drinking, irrigation and industrial use.

* Survey of pollution of ground water sources enabling identification of point sources of pollution and preventive action.

* Remedial measures for ground water quality would ensure utilizing the damaged ground water resource.

* Better management of coastal aquifer would be possible ensuring supply of potable water in coastal areas. Problem of land subsidence shall also be avoided.

* Educational Institute for Water Resource Engineering shall facilitate availability of manpower in this sector.

* Evolution and implementation of proper organizational structure would facilitate co-ordination of activities between different agencies, avoid duplication of work, improve communication and sharing of data, expedite decision making process and identify role and responsibility for implementing decisions making process and identify role and responsibility for implementing decisions for efficient and effective ground water management.

* By allowing channelisation of private sector funds, the constraint of financial resources shall be tackled.

* Formulation of National Water Policy shall facilitate conjunctive use of surface and ground water as also pave the way for coordinated efforts for sharing and utilization this resource in the best interest of the country.

6. Spin off Benefits

Various spin-off benefits of economic and socio-economic nature would be:

* Increase in agricultural output due to better irrigation support from ground water resources and construction of structures for run-off water conservation during monsoon to be used later in the lean months.

* Generation of employment opportunities in various projects that will be implemented requiring construction, drilling and other related activities.

* Development of technical expertise in the country that would be of use in other fields as well e.g. remote sensing can be used in numerous other applications.

* Improved environmental conditions due to adoption of industrial zoning, pollution control measures and recycling of waste water.

* Improvement in hygiene due to availability of good quality water.

* Increase in income for the average farmer due to better irrigation support from ground water resources and improvement in his standard of living.

The above mentioned benefits are qualitative as it is not possible to quantify the benefits, which would be very specific to a project adoption one or more of the techniques. The efficient usage of the precious ground water resource will be the result.