ACTIVITIES (2003 - 2004)

Central Ground Water Board, SouthWestern Region has its jurisdiction of  Karnataka and Goa States. Theses States are looked after by the Regional office and Unit office located at Bangalore and Belgaum respectively. The region came into existence in June 1982.The unit office which was established in 1969 and existing in Bangalore was shifted to Belgaum in 1986. Karnataka State having an areal extent of 1,91,791 sq.km.  is  divided into 26 districts and 175 taluks. The State is comprising of four distinct physiographic units viz., (i) Northern table land (ii) Southern table land (iii) Malnad region with hills and valleys  (iv) Narrow coastal plain along the west coast Cauvery, Thungabhadra, Krishna, Godavari, Palar, Pennar and  west flowing rivers like Netravathi, Kali are the major river systems drain   in the State. The rainfall pattern varies from  30  to 600 cm per annum.  Crystallines and Metamorphic rocks cover 97% of the area and 3%  is covered by alluvium along the coast and major rivers.

Goa State  covers an area of 3702 sq.km,  comprises  of  two districts namely North Goa and South Goa. The distinct physiographic units of Goa comprises of Western ghat hills in the west graded down to well dissected plateau in the middle and coastal plain in the east. Among nine rivers draining in the State, rivers like Terekal, Chapara, Zuari, Mondovi are the important ones. Metamorphic rocks like phyllites, schists. granites and gneisses are the important  rock types  apart from alluvium which is restricted along  the  coast. Laterite  occurs extensively in the state where the  occurrence of groundwater encountered  commonly.  

            The  work   programme  is  broadly  covered  under following activities.

*  Systematic and reappraisal hydro geological surveys.

*  Exploratory drilling.

*  Ground water regime monitoring.

*  Hydro chemical analysis. Remote sensing, Geophysical, Hydrological, and                                 

    Hydro meteorological  studies.

*  Ground water resource estimation.

*  Special project studies like artificial recharge and conjunctive use projects

*  Assistance to State government and semi government organisations,Public 

    sector undertakings including Technology Mission for Rural water supply.

* Pollution Studies like Ground Water In land salinity, Coastal Salinity and Land fill

   studies in urban areas etc.

*  Hydrology project.

*  Preparation and issuance of various reports and maps.

STATUS OF WORK :

Activities undertaken during various Annual Action Plans of Central Ground Water Board, SouthWestern Region, Bangalore, is presented below. 

1.   SYSTEMATIC AND REAPPARAISAL HYDRDOGEOLOGICAL SURVEYS

  Systematic hydrogeological surveys were carried out in the entire  state covering 1,91,791sq.km. Reappraisal hydrological surveys were carried out in the entire state except in Kollegal taluk. District Ground Water Management Studies have been proposed for the second generation reappraisal surveys for the districts where a span of half decadal period has been completed and accordingly such studies have been extended in Bagalkot, Bidar, parts of Bellary, parts of Chitradurga district, parts of Davanagere district, and parts of Dakshina kannada district. In addition basin studies have been carriedout in Arakavathi Basin covering parts of Bangalore and Kolar districts and Kagna  basin covering parts of Gulbarga districts .  Like wise Micro level surveys have been carried  out in parts of Dakshinakannada district, parts of Tumkur district, parts of Bangalore district, parts of Davanagere district and parts of Belgaum district wherever certain taluks of said districts have been declared ground water Over Exploited  / Dark blocks. These studies have imparted a basic database, which can access very well for formulation execution of better ground water management practices. In addition the above Urban hydrogelogical survey has been carried out in Bangalore Metropolitan area.

2. EXPLORATORY DRILLING

Under the first approximation resource evaluation studies as stated above various types of bore holes like exploratory, observation and piezometer wells have been drilled for generating scientific data in various geological formations of Karnataka.  This information includes the thickness of weathered layer, occurrence of fractures in crystallines and vesicular zones in deccan basalts, cavernous limestones, and potential zones in coastal alluvium. The slim hole drilling have been attempted in the coastal area of Dakshina Kannada district and in other geological formation of Karnataka to understand the subsurface geology and to adopt a suitable methodology for the construction of production wells. To study the behavior of ground water levels in time and space, piezometer and piezometer nests were constructed to study the phreatic and other aquifers. A brief of various salient data of drilling programme in Karnataka and Goa are presented below.

 MULTI DISIPILINARY STUDIES

 (a) Karnataka

  A multi disciplinary ground water project was taken up with Canadian Assistance (1971 – 1975) envisaged mainly for basaltic terrain covering parts of Andhrapradesh and Karnataka which covers an area of 505 sq.km in parts of  Gulbar­ga and Bidar  districts of Karnataka. Vedavathi River Basin Project was  taken  up  during 1975-80 covering an area of  19,000  sq.km.  falling  in parts of Chitradurga, Chikamagalur, Hassan,  Shimoga, Bellary  and  Tumkur districts. The aims of the  project  studies were to develop methodology for scientific and rational development  of ground water in crystalline terrain and for  quantifica­tion  of  ground water resources and  determination  of  Specific yield percent of the formation and minimum rainfall required  for recharging the ground water body. Ground water  evaluation was carried out during 1979-81 in trap Bhima crystalline  fringe areas and Kaldgi formation ( sandstone, shales and  limestones) in  Gulbarga and Bijapur districts. Since the formation of  South Western Region and Division XIV in Bangalore in 1985 , Explorato­ry  drilling  has been taken up as part  of resource  evaluation study  in upper Pennar basin, Don-Bhima basin and  drought  prone districts of Bangalore, Belgaum, Bellary, Bijapur,  Chitradurga, Dharwar, Gulbarga, Hassan, Haveri, Kolar, Mandya, Mysore, Raichur, Tumkur,  Kodagu and Dakshina Kannada and normal areas of Bidar, Uttara Kannada districts. In all 781 exploratory wells, 356 observation  wells, 9 slim holes, 5 deposit wells and 367  piezome­tres (HP)  have  been  drilled in the State by  Central Ground Water Board. Out  of these 60 % of the exploratory wells are capable  of yielding 10 m³ per hour for less than 30m drawdown.  Yield characteristics of borewells tapping various aquifers are tabulated in table.1

(b) Goa

  Under the first  approximation  resource evaluation studies exploratory and observation wells have been drilled for generating scientific data in various geological formation occurring in the state.  This information includes the thickness of weathered layer, occurrence of fractures in crystalline and potential zone in coastal alluvium. Taluk wise distribution of exploratory and observation wells are tabulated below in table.2.

Table: 1 Yield range of exploratory bore wells tapping different aquifers in Karnataka.

Table 2 : Talukwise distribution of exploratory and observation wells in Goa State.

                        Total for Goa State 54+19 = 73 nos.

The major aquifers are in granites and granite gneisses, meta-basalts, meta-sediments metagrey wackes and alluvium.  The formation wise distribution of exploratory and observation wells are tabulated in table.3

            Based on litho logs of select 19 exploratory wells in the state, it is inferred that in the northern, Northwestern part and in central Goa laterite thickness is predominant, whereas on the eastern fringe areas and southern parts of Goa State the same is negligible or nil.  Further in Salcete taluk, alluvium of 12-21m thickness rest on granites and gneisses.

 Table.3 Formation/Aquifer wise distribution of exploratory and observation wells in Goa State.

Aquifer parameters of fractured rocks (deeper zones)

Down to the basement ground water occurs in planar porosities such as joints, fractures and its movement is controlled by geometry of structural weak planes and their inter- connection rather than morphological control as in the case of water table aquifers.  The water in them exists either in confined or semi-confined state. Unlike granular unconsolidated sediments, these fractured rocks exhibit lateral and vertical anisotropism in yield and aquifer parameters, which is tabulated in table.4

Alluvial aquifers, metabasalts, metagreywacks and meta sediments (mostly schists, fractured quartzites and phyllites) are better aquifer than granites and gneisses.  Exploratory wells in meta-basalts, metagreywackes and metasediments falling on well defined intersecting weak planes have yields from 9.9 to 13 lps with a draw down in a range from 1.18 to 18m.  Some of the exploratory wells falling on open intersecting fractures are given in table.5

Handing over of exploratory wells

The status of Handing over of exploratory wells in Karnataka is as follows:

As per the recent decision conveyed by the Ministry, The wells were offered by Central Ground Water Board on free of cost for the effective utilization of the State Govt. to put into use of these wells for water supply schemes. High yielding wells constructed by CGWB in drought districts of Karnataka will be immense of use during drought mitigation time.

As per the status position of handing over of exploratory wells is concerned exploratory wells drilled in Karnataka and  Goa State have been handed the States accordingly.

Table: 4   Range of yield characteristics and aquifer parameters  for important fractured  aquifers in Goa State.

A = Range in Parameters,  B = Average of Parameters.

Table:5  Hydrological parameter of various aquifers tapped in Goa State

3. NATIONAL HYDROGRAPH NETWORK STATION MONITORING PROGRAMME

            Monitoring of ground water levels through a network of observation wells is essential to assess the effects of rainfall and the impact of withdrawal ground water for the developmental work on the ground water regime. In a Hydrogeological system the impact of recharge due to infiltration and discharge due to extraction is reflected through rise or fall of ground water levels. Rainfall being the major component of recharge to ground water, infiltration of part of the rain water during the monsoon period produces a recharge to ground water resulting in a rise in ground water levels. During post monsoon period extraction of ground water is the dominant feature and this results in a decline in ground water levels till the onset of monsoons. 

            In Karnataka Central Ground Water Board had a network of 1206 observation wells as on March 2000. Subsequently some of the network stations that were filled up/closed/consistently dry were abandoned, thus reducing the total network to 1132 stations (table.6). The network observation stations are monitored four times a year during the months of May (pre monsoon), August (mid monsoon), November (post monsoon) and January (non monsoon). The water levels thus collected have been critically analysed to determine the following features namely,

a. Distribution of ground water levels.

b. Seasonal and annual fluctuation in ground water levels and decadal change in storage.

The observations on ground water level behavior in Karnataka and Goa are described below.

3.1 Karnataka:

            During the pre monsoon (May) period the depth to water levels are deeper than the other measurements as withdrawal from ground water is the dominant component prior to these measurements. The pre-monsoon water levels recorded in Karnataka ranged from 0.17 to 24.43 mbgl. Shallow water level of 2 to 5m has been recorded in parts of Bidar, Gulbarga, Raichur, Bellary, Bagalkot, Gadag, Koppal, Davanagere, Chikamagalur, Shimoga, Mandya, Mysore and Bangalore districts.  The shallow water levels are due to canal irrigation in some parts and less stress in terms of ground water development in others. The water level of 5 to 10 m is the general water level occurring throughout the state in parts of almost all the districts and recorded in 47% of the NHNS. Moderately deep water level of 10 to 20 mbgl occurs in about 24% of NHNS as pockets scattered throughout the state with larger areal extent in parts of Bidar, Dharwar, Gadag, Haveri, Koppal, Shimoga and Davanagere districts. These deeper water level parts represent the areas of higher ground water stress in terms of draft. Water level of >20 mbgl has been recorded as localized pockets in parts of Bidar, Bagalkot, Belgaum, Haveri and Mandya districts which account for about 1% of the data analysed.

            During the post monsoon (November) period the depth to water level ranged from 0.13 to 22.86 mbgl. It is observed that about 90% of the state area have water levels within 10 mbgl. 2 to 5 mbgl and 5 to 10 mbgl are the general water levels occurring throughout the state found in parts of almost all the districts of the state.  Shallow water level of less than two metre is recorded in parts of Bidar, Gulbarga, Belgaum, Dharwar, Raichur, Koppal, Shimoga, Mysore, Mandya and Bangalore districts. Depth to water levels of 10 to 20 mbgl occurs as scattered pockets with larger areal extent in parts of Bidar, Dharwad, Gadag, Koppal, Haveri, Bellary, Davanagere, Shimoga, Chitradurga, Tumkur and Kolar districts. This is due to comparatively higher ground water development in some parts and due to proximity to recharge areas in other parts. More than 20 mbgl water level is found in very small area of the state as localised pockets.

Annual Ground Water fluctuations for Pre and Post - Monsoon :

Annual pre monsoon fluctuations between May 01 and May 2002 analysed for Karnataka indicates that the rise in water level of 0-2, 2-4 and more than 4 m has been recorded in 22.3%, 3.4% and 2.8% NHNS respectively. Whereas fall in water level of 0-2, 2-4 and more than 4 m is found in  49.8%, 16.8% and 5% respectively.   During the post monsoon period between Nov, 2001 to Nov, 2002 the State has recorded a rise in water level of 0-2 and 2-4, and more than 4 m as 42.8%, 8.3% and 3.5% respectively. Whereas the fall in water level of 0-2, 2-4 and more than 4 m has been recorded as 36.5%, 6.5 % and 2.5% respectively.

  Seasonal Ground Water fluctuations between Pre and Post monsoon (May 02 – Nov.02):

  Seasonal fluctuations between May 2002 and Nov.2002 analysed for Karnataka indicates that the rise in water level of 0-2, 2-4 and more than 4m has been recorded in 29.4%, 35.8% and 28.4% NHNS respectively. Whereas fall in water level of 0-2, 2-4 and more than 4m is found in 5.4%, 0.4% and 0.6% respectively.

  Decadal Change in Ground Water Level During Pre and Post monsoon :

Comparison of pre and post monsoon ground water levels with the mean water levels of the preceding decade gives a picture of long term change in water levels. Comparison of mean water level for the period May 92 to May 01 with May 2002 water levels indicates that the rise in water level of 0-2, 2-4 and more than 4m has been recorded in 52.9%, 13.2% and 5.5% NHNS respectively. Whereas fall in water level of 0-2, 2-4 and more than 4m is found in  22.1%, 4.8% and 1.4% respectively.   For the post monsoon period comparison of mean water level for the period Nov. 92 to Nov.01 with Nov. 2002 water levels indicates that the State has recorded a rise in water level of 0-2 and 2-4, and more than 4m in 54.0%, 17.6% and 5.9% respectively. Whereas the fall in water level of 0-2, 2-4 and more than 4m has been recorded in 18.1%, 3.2 % and 1.1% respectively.

  Status of Ground Water Regime by latest monitoring of NHS during January 2003

CHANGE IN GROUNDWATER LEVEL, May 2002 TO Jan 2003

    Water levels from 680 stations were compared to know the annual change in groundwater level in Jan 2003 with that of May 2002.  On the whole 447 wells, amounting to 66% of the analysed wells have recorded a rise in water level during Jan 2003.   The balance of 223 wells, amounting to 34% have recorded a fall.

     In the rise category, the rise of water level in the range 0-2 m is the most prominent and is observed in 286 wells accounting for 42% of the analysed wells.  Rise in water level in the range of 2 to 4 m. and >4 m. is recorded in 129 wells (19%) and 32 wells (5%) respectively.

     In the fall category, the fall of water level in the range of 0 – 2 m is prominent and is observed in 169 wells accounting for 25 % of analysed wells.  Fall of water level in the range of 2 to 4 m. and > 4 m are seen in 48 wells (7%) and 16 wells (2%) respectively.

     A map depicting the change in groundwater level in January 2003 as compared to May 2002, showing rise/fall in the ranges of 0 to 2 m, 2 to 4 m and >4 m was prepared (Plate IK). The map shows that major portions of the state show either a rise or fall in groundwater level in the range of 0 to 2 m.  Between the two, the ‘rise in water level area of 0 to 2m’ is more as compared to the ‘fall in water level area of 0 to 2m’

     The map shows that rise in Ground Water of 0 to 2m.,is prominent in northern, southern and western parts of the  state. Parts of Bidar, Gulbarga, Bijapur, Bagalkot, Belgaum, Bellary, Raichur, N.Kanara, Udupi, Coorg, Shimoga, Dakshina Kannada, Tumkur, Mysore, Chamarajanagar and Bangalore districts have recorded rise between 0 to 2 metres. Rise of 2 to 4m, occurs as pockets in parts of Bidar, Gulbarga, Bijapur, Bagalkot, N.Kanara, D.Kanara, Shimoga and Chamarajnagar districts. Rise of >4m., is found as very small pockets in Bidar,  Gulbarga, Bijapur, Bagalkot, Belgaum, Bellary, Raichur, N.Kanara,  Dakshina Kannada, Tumkur,  Mysore and Chamarajanagar  districts.

     In the fall categories, a fall of 0-2m is prominently observed in  central and Eastern parts of the state covering parts. In the other parts of the state it was in pockets. Fall of 2 to 4m. occurs as small pockets in Belgaum, Chikmagulur, Bangalore, Mysore and Coorg Districts. Fall of >4m., occurs as islands in parts of Belgaum, Chikmagulur, Bangalore, Mysore and Coorg Districts. 

CHANGE IN GROUNDWATER LEVEL, JAN 2002 TO JAN 2003

    Water levels from 737 stations were compared to know the annual change in groundwater level in January 2003 with that of January 2002.  On the whole 277 wells amounting to 38% of the analysed wells have recorded a rise in water level during January 2003. The balance, 460 wells amounting to 62% have recorded a fall. (Annexure II b)

     In the rise category, the rise of water level in the range 0-2 m is observed in 249 wells accounting for 34% of the analysed wells.  Rise in water level in the range of 2 to 4 m. and >4 m. is recorded in 22 wells (3 %) and 6 wells (1 %) respectively. In the fall category, the fall of water level in the range of 0 – 2 m is observed in 301 wells accounting for 41 % of analysed wells.  Fall of water level in the range of 2 to 4 m. and > 4 m are seen in 100 wells (13%) and 59 wells (8 %) respectively.

     A map depicting the change in groundwater level in Jan 2003 as compared to Jan 2002, showing rise/fall in the ranges of 0 to 2 m, 2 to 4 m and >4 m was prepared (Plate IIK). The map shows that major portions of the state show either a rise or fall in groundwater level in the range of 0 to 2 m.  Between the two, the ‘fall in water level area of 0 to 2 m’ is more as compared to the ‘rise in water level area of 0 to 2 m’

     The map shows that rise in Ground Water of 0 to 2m. is prominent in northern and western  parts of the  state. The rise is in isolated pockets in rest of the state. Rise of 0 to 2 metres was recorded in parts of Bidar, Gulbarga, Belgaum, N.Kanara, Udupi, Coorg, Shimoga, Dakshina Kannada, Mandya, Davangere, Hassan and Chamarajanagar districts. Rise of 2 to 4m., occurred as small  pockets in parts of Bidar,  Davangere, Udupi, Hassan  and Dakshina Kannada   districts. Rise of >4m. is found in  and very small pockets in Hassan and Davangere districts.

     In the fall categories a fall of 0-2m is prominent in the entire state except in northwestern parts. Fall of 2-4 metres is observed in Bijapur, Bagalkot, Gadag, Bellary, Bangalore Chikmagalur, Raichur, Kolar, Hassan, coorg and Mysore . Fall of >4m. occurs as islands in parts of Bellary, Chikmagalur, Hassan, Mandya, Kolar, Mysore, Coorg and Chitradurga districts.

CHANGE IN WATER LEVEL, MEAN (Jan 93 TO Jan 02)-Jan 03

     Mean groundwater level for the period Jan 1993 to Jan 2002 was compared with the groundwater level in Jan 2003. It is seen that out of the 753 stations compared, 315  stations accounting for 42 % showed a rise in water level during Jan  2003 as compared to preceding  decadal mean and the remaining 438 wells  or 58 %  showed a fall.  (Annexure II c)

     In the rise category, a rise of 0-2 m is most prominent and is recorded in 285 stations accounting to 38 % of analysed wells.  A rise of 2-4 m and >4 m is seen in 26 wells (3 %) and 4 wells (1%) respectively.  In the fall category, a fall of 0 – 2 m is the most prominent and is recorded in 281 wells accounting to 37% of analysed wells.  Fall of 2 to 4 m and >4 m is seen in 108 wells (14%) and 49 wells (7%) respectively.

     A map showing the change in water levels as described above, showing rise/fall in the ranges of 0-2 m, 2-4 m and >4 m was prepared (Plate – IIIK).  The map shows that parts of northeastern, coastal, southern  and malnads have shown a rise. A rise of 0-2m is most prominent and is found to occur in Gulbarga, Raichur, Bellary, Tumkur, Bidar,  D.Kanara, Chikmagulur, Udupi Shimoga, N.Kanara, Mandya, Hassan, Chamarajangar  and Bagalkot. Rise of 2 to 4 m occurs as small pockets. Rise of >4 m., occurs as small localized patches in parts of Hassan and Bidar  district.

       In the fall categories, fall of 0-2m. is prominently seen in parts of Bidar, Bijapur, Bagalkot,  Belgaum, N.Kanara, Shimoga, Mandya, Mysore, Hassan, Dharwar, Chamarajanagar, Haveri, Gadag, Koppal, Chitradurga, Chikmagalur, Bangalore, Coorg, Udipi, Mysore, Davangere and Kolar districts. Fall of 2 to 4m. occurs in Bidar, Bijapur, Bagalkot,  Belgaum, N.Kanara, Shimoga, Mandya, Mysore, Hassan, Chamarajanagar, Haveri, Gadag, Koppal, Chitradurga, Chikmagalur, Bangalore, Coorg, Udipi, Mysore,  and Kolar districts. .  Fall of >4m., was noted in Dharwar, Belgaum, Haveri, Coorg, Bangalore and Kolar mostly localised in nature. 

DEPTH TO WATER LEVEL Jan 2003

     The depth to water level recorded in the state ranged from 0.32 mbgl (Belgaum district) to 26.05 mbgl  (Chikmagulur district). It is seen that out of 782 stations monitored during the month, 6 % wells have less than 2 mbgl water level, 27 % wells have 2 to 5 mbgl water level and 51 % wells have 5 to 10 mbgl water level.  Thus, about 84 % of the analysed wells have water level within 10 mbgl.  Moderately deep water levels of 10 to 20 mbgl are seen in 15 % wells and deep water levels of > 20 m is found in about 1% of the analysed wells. ( Annexure  III )

     A map showing the depth to water level in the ranges of <2, 2to5, 5to10, 10to20 and >20mbgl was prepared (Plate IVK).  The map shows that major portion of the state is having a water level of 5 to 10 mbgl, followed respectively by 10 to 20 mbgl and 2 to 5 mbgl water levels. Depth to water level of <2 mbgl and >20 mbgl occupy very small areas. It is seen from the map that water level of 5 to 10 mbgl is generally found throughout the state occupying parts of most of the districts. Water level of 10 to 20 mbgl is also found in almost all the districts and is prominently seen in the central and southern parts of the state. 2 to 5 mbgl water level is found as small pockets scattered all over the state with larger areal extent in parts of Gulbarga, Raichur, Bellary, N.Kanara, Udipi, S.Kanara, Coorg, Chikmagalur, Shimoga, Mandya, Chamarajanagar and Bangalore districts. >20 mbgl water level is found as very small pockets in parts of Dharwar, Koppal  Bagalkot and Gadag districts.

3.2. Goa:

            The details of network observation stations, which are being, monitored in Goa state is shown in table 7. During the premonsoon (May) period depth to water level ranges from 1.00 to 18.92 mbgl. In general depth to water level between 2 and 5m in 6 taluks of North Goa district and 2 taluks of South Goa district.

            Depth to water in the range of 5 to 10m is observed in Satari taluk and as isolated patches in 3 taluks. Deep water levels in the range of 10-20m are observed as patches at Satari, Sanguem, Canacona ,and Quepem and Pernem taluks. The shallow ground water levels of 2 to 5m is observed in majority area in Pernem, Bardes, Bicholim, Satari, Tiswadi and Ponda taluks in North Goa district and Marmugoa, Salcete, Quepem and Canacona taluks of South Goa district. Less than 2m ground water level is observed in parts of Pernem, Tiswadi taluks of North Goa district and parts of Canacona, Quepem, Sanguem taluks of South Goa district.

Ground water fluctuation scenario between May and November  :

The rise in ground water level varied from 0.12 to 7.06 m and from 0.08 to 2.80 m in South Goa and North Goa respectively. The decline in ground water level varied from –0.2 to –3.71m and from less than one meter to –5.50m in South Goa and North Goa districts respectively. The rise and fall of less than one metre to 2m is observed in most part of the state, The rise and fall of more than 4m is observed in Salute and Sanguem taluks of South Goa district and Tiswadi taluk of North Goa district respectively.

                           Table 7: District wise distribution of NHNS in Goa

4. HYDROCHEMICAL ANALYSIS, REMOTE SENSING , GEOPHYSICAL AND

     HYDROMETEROLOGICAL STUDIES

a) Hydrochemical analysis:

            In the regional chemical laboratory of SWR, a total of 12873 water samples were analysed between 1992 - 2001. The details are presented in table.8 both for Karnataka and Goa. Based on the Chemical analysis of water samples, following reports and maps were prepared.

*  Water quality maps/Reports 

*  Ground Water Yearbook showing distribution of electrical conductivity.

*  Chemical Analysis Data up to 1998 has been computerised.

Interpretation of chemical quality of ground water: For the assessment of general ground water quality ground water samples collected from Hydrograph stations / Systematic and Reappraisal surveys / Exploratory well programme / Hydrology Project (HP) /Special studies/ etc have been analysed for parameters such as EC, Cl, SO₄, NO₃ and F apart from other parameters like Na, K, Mg,and Hardness etc. The results are grouped into three categories corresponding to Bureau of Indian Standards for drinking water (1991) vis-a-vis desirable, permissible and unsuitable category. The chemical analysis carried out for various samples reveal that by and large ground water quality of Karnataka and Goa states are suitable for drinking / domestic purposes except in some industrial pockets where high nitrate content is reported.

Table.8 Status of hydrochemical analysis

b) Remote Sensing studies

As a part of resource evaluation studies and as additional  input for  hydrogeological surveys, studies are undertaken using  air photos and land sat imageries. Besides utilising them in explora­tory  drilling programme, Remote sensing studies have  also  been used  in  delineating potential zones in respect  of  drought prone  districts of Chitradurga, Dharwar, Kolar, Bangalore,  Tum­kur,  Gulbarga,  Belgaum, and Raichur districts and  tribal  dis­tricts  of Dakshina Kannada  and Kodagu. Visual  interpreta­tion  of  the imagery and Digital analysis were also carried  out in parts of Raichur district under application validation programme with Department of Space.

As a part of MOU with NRSA, Hyderabad, Central Ground Water Board was involved into the quality check evaluation of the Ground Water Prospects Maps under Rajiv Ghandhi Drinking Water Mission with State Remote Sensing Cell. Govt.of Karnataka.

c) Hydrometerological studies

Monthly and annual rainfall data for the raingauges located at the headquarters of the 175 taluks are collected, compiled and stored in the rainfall data base file.  This database file is part of the Hydrometerological Information System, developed and being used in this region.  This software facilitates consist of retrieval of data in the desired format. Statistical analysis and averages based on polygons can also be computed.  Rainfall data from 1901 to 1998 is available in the database. Under experimental artificial recharge studies in Kolar district, analysed and computed tank water balance and stream flows pertaining to Gauribidanur and Mulbagal taluks. A weather station which was established during the course of VRBP was continued till 1988, wherein all the parameters  such  as rain fall intensity, evaporation,  wind  velocity, humidity,  max.- min.temperature, sunshine hours  were  recorded daily. Information collected is analysed for estimating the water surplus  from rainfall and is correlated to the rise  in  ground water level recorded in the area. Rain gauge station has also  been established in Bidadi watershed in Bangalore district.

Software developed in dBase III plus and Fox plus in  association with National Informatics Center. Work is also  in progress  for computer based data management system for the  data generated  during hydrogeological surveys and exploratory  drill­ing.

 d)  Geophysical Surveys:

Geophysical survey both surface and well logging are taken up as a part of ground water exploration programme. Surface studies are also taken up in connection with Water supply investigations  for pinpointing  sites  where drilling can  be  taken  up. Geophysical logging  helps  in delineating the fractures encountered  in  the bore holes and is also utilised in designing the wells in coastal alluvium,  where  quality variations of the formation  water  are noticed.

Geophysical  surveys in Karnataka comprising Vertical  Electrical Sounding  (VES), Resistivity profiling and VLF surveys were  con­ducted in different parts of the state to

* Estimate the thickness of the aquifers

* Estimate overburden thickness.

* Delineate sheared and fractured rocks

* Locate structures like dykes, Faults etc. which control the   

   Ground water movement.

* Study the relative variation of the Quality of Ground water.

3190 VES, Resistivity/VLF profiling for a length of 27.15-line km were carried out. Based on the results, suitable recom­mendations were communicated for taking up drilling.

Geophysical logging is carried out in the state in 117 bore wells in the depth range of 70.0 - 300 meters. The logging comprises recording of Self Potential (SP), Point resistance (PR), N 16" & 64"normal resistivity and lateral receptivity using  lateral log  and gamma activity.

5. GROUND WATER RESOURCE ESTIMATION        

The recharge to ground water is mainly through precipitation, apart from other sources like return flow from applied   irrigation, tanks etc.  The state predominantly underlain by the hard rock aquifers, which responds quickly to the rainfall and starts building up of the water levels. During the summer period the depth to water shows falling trend with appreciable dwindling of   resources and fall in discharge of wells.

a). Ground Water Resources availability in Karnataka.

The total replenishable ground water of Karnataka as per ground water estimation committee methodology (1984) is estimated as on March’92 as 1.6175 million hectare metres (Mha.m) and out of this 0.2418 Mha.m has been kept for domestic and industrial uses.  The district wise ground water availability and potential created upto 1998 along with balance available for development has been given in the table 9. Out of the 175 taluks/blocks, 6 taluks are over exploited and 8 taluks fall in dark category and 13 taluks fall in the grey category  (table.10).

The estimated utilisable irrigation potential from ground water is 2.44268 million hectares and as on March’98 about 0.80608 million hectares had been developed and an area of 1.63660 million hectares are still to be developed.

TABLE  9 : Ground Water Resources and Irrigation potential of Karnataka

as  on March 1998.

1   - Serial Number         

2   - Districts

3   - Annual Natural Recharge (Mha. M)

4   - Provision for drinking and industrial use (Mha. M)

5   - Available recharge (Mha. M)

6   - Utilisable recharge (Mha. M)

7   - Net draft (Mha. M)

8   - Balance GW available (D-E) in Mha. M

9   - Utilisable irrigation potential for development (Mha)

10 – Stage of development in percentage.

Table.10: Grey (Semi-Critical), Dark (Critical) and Over- Exploited blocks in

Karnataka (As on March 1998-Provisional)

b). Ground water resource availability in Goa.

            The estimated utilisable ground water resource of the state is in the order of 165 MCM and the net draft projected up to March 1998 is 16 MCM. The balance ground water resource for future development is 149 MCM. The stage of Ground Water development is less than 10 percent except in Ponda and Tiswadi taluks where it is 15 % and 14 % respectively. In Canacona taluk, the stage of development is 31 %.

6.  SPECIAL STUDIES  :

a) Experimental Artificial Recharge Studies in Kolar District, Karnataka.

Ground water irrigation has gained importance during the last decade in Karnataka through dugwells, dug-cum-borewells and borewells in some districts, especially in areas where perennial rivers are absent.  Kolar is one among such  districts which has experienced high stage of ground water development where a spurt in groundwater activity is seen during the past two decades.  The periodical monitoring of wells for the period 1973 to 1996 shows a declining trend in ground water levels.  The area showing declining trend in ground water levels are associated with higher degree of ground water development.

Central ground water Board under Central Sector scheme has initiated Experimental Artificial Recharge Studies (EARS) in Gauribidanur and Mulbagal taluks during 1993-94 and continued in the subsequent years.

The main activities are :

Desilting of two tanks, one each in Gauribidanur and Mulbagal taluks and converting the same into Percolation tanks.

Watershed treatment in two areas

Construction of point recharge structures (5).

Gravity recharge wells.(2)

Roof top rain water harvesting structure at Gauribidanur.

Construction of Percolation Tanks:  

The existing defunct and silted up M.I. tanks at Errapothenahalli and Manchiganahalli were taken up for conversion to percolation tank after desilting.  Government of Karnataka had plans to take up desilting of M.I. tanks in Kolar district on a large scale and in this context the district level authorities emphasized the need to quantify the additional recharge through such desilting programme.  Keeping this in mind, it was planned to take up study of the tank bed seepage prior to desilting and after desilting and thereby quantifying the same.

 Watershed Treatment :  

Treatment of Basavapura and Bhovibikkanahalli micro-watersheds with traditional water harvesting structures to study the impact   the same on ground water recharge.  The studies were taken up as watershed development programme, which are being taken up in Karnataka on a large scale and the present study attempts to quantify the additional recharge by such programmes. Check dams are the major structures constructed under this programme.

 Point Recharge Structure (PRS)

  Five PRS were taken up in the district.  The construction of PRS involves two stages of work.  Firstly, the construction of a borewell for recharge and secondly, designing a filter bed around the recharge borewell.  The surface water either from the M.I. tank or from the nalla is allowed into the filter bed.  The silt free water from the filter bed will be let into the recharge borewell tapping fractured aquifer.  The drilling of recharge borewells together with observation wells (ie: recharge well field) were taken up by CGWB.  The five well fields are located at Hosur (two nos.), Bhakthara halli, Sonaganahalli and Manchiganahalli. 

  Gravity Recharge Wells :

  Two gravity recharge well fields were constructed, one each at Belchikkanahali and Hussainpura.  A short duration injection test was conducted in these two well fields and tested for their intake capacity rates.  The source water for the tests was transported through pipe  line from an existing irrigation borewell located about 700 meter away from the well field.

Findings of Artificial Recharge Studies:

Percolation tanks  :

Infiltration tests results carried out at Percolation tank beds prior to and after desilting showed an improvement in tank bed percolation. The infiltration rate ranged from 0.17 to 2.4 cm/hr prior to desilting whereas the rate has increased in the range of 1.8 to 8.8 cm/hr after desilting at Errapothenahalli.  At Manchiganahalli, it ranged from 1.2 to 5.8 cm/hr prior to desilting whereas the same was observed to be in the range of 10 to 16.8 cm/hr after desilting. The ground water level data during post desilting periods reveals a built-up in storage in the order of 2 to 4.5 m to the downstream of the tanks.

Watershed treatment  :

It has revealed that the flow recorded is considerably reduced after the treatment and the construction of the structures.  A built-up in storage was observed to be in the order of 3 to 5 m in the phreatic zone. The treatment of Basavapura  microwatershed has shown watershed treatment can arrest flows during monsoon and enhance recharge to ground water.  This indicates that  watershed treatment especially in the drought prone district of Karnataka can be taken up on a large scale  which can contribute greatly to recharging of ground water and retention of moisture for crop production.

Point recharge structure  :  

The recharge through point recharge structure has benefited the deeper aquifer to build-up storage locally and to improve the ground water potential and are effective in recharging deeper aquifer and can be applied in feasible areas of a drought prone district.

Gravity recharge experiments:  

The experiments carried out at Belchikkanahalli and at Hussainpura have indicated 3 to 4 lps intake of the aquifer (weathered and fractured granite gneisses) with a possibility of creating additional storage using the excess water available in Bandihalla. This can be adopted successfully in similar environs having surplus source water.  The source water has to be clear and silt free before recharge. Stream flow and tank water are  ideal as source water.

  The total amount sanctioned under the EARS is Rs. 44.116 lakhs and this amount has been released to State Government by CGWB under the central sector scheme.  

(b) Artificial Recharge studies in Jnanabharathi campus, Bangalore University:

Under Central Sector Scheme, a scheme on artificial recharge to ground water is being executed  in Jnanabharathi campus, Bangalore University which cover an area of about one sq.km. The scheme on completion would harness 0.043 MCM (43,000 m³) monsoon run-off going as waste and can improve  ground water levels and sustainability of abstraction structures in the area through artificial recharge structures such as Check dams and subsurface dyke. This scheme is only  a beginning in the University campus and all the plans are on the advanced stage to launch a model environmental eco-park in association with  the University.

The salient features of the scheme are:

Total water available for recharge : 43290 cu.m

The  benefits include direct and indirect in any concerned artificial recharge schemes. An attempt is made to harness the natural surface water run-off  (43290 cu.m) to recharge the aquifer system instead letting it into a  drainage course. This will  help to maintain the productivity of the existing water supply borewells which supplies water to the University and Sports Authority of India campus.  The scheme after completion is likely to recharge about 21645 cu.m (50 percent of 43290 cu.m) of potable water into the depleting aquifer system in the area. Considering 20 years span of life for the structures, the annual investment with 10 percent rate of interest works out to rupees 80740. The cost per thousand liters of water harvesting works out to about two rupees. In addition to above, the possible intrusion of  polluted Vrishabhavati water to the aquifer in the area will be prevented.

            An amount of Rs.13.75 lakhs was sanctioned for the scheme. Execution of the recharge structures were completed.

c) Conjunctive Use Studies In Ghataprabha River Basin.

 Conjunctive use study of surface and ground water in Ghataprabha river basin in parts of Belgaum and Bijapur districts has been carried out covering an area of 10,370Km²_.  The data from CGWB and state agency have been utilised in this study. Ground water modelling studies were also undertaken during the project period.

The study indicated that canal water utilisation in the left banks command is 1114 MCM and the total water utilisation is 2070 MCM leaving a balance of 1015 MCM for further use one of which 529 MCM is surface water.  By increasing the cropping intensity a conjunctive use plan can be drawn. Non utilisation of ground water in upper reaches of the basin has resulted   the water logging condition.  In tail end area water deficit is experienced. 

A conjunctive use plan has been drawn both for left and right  bank canal command areas with optimal utilisation of surface and ground water.  Under this a suggestion put forth for left bank canal is that utilisation of surface water to a tune of 1068 MCM (84%) and ground water to a tune of 173 MCM (16%) can boost up the cropping intensity to 200% likewise in the case of right bank canal a cropping intensity of 140% has been suggested by utilising surface water to a tune of  712 MCM and ground water to a tune of 223 MCM.

A total investment of Rs 40.5 crores has been suggested for construction of   20,691 borewells upto a depth of 80m covering 10 taluks of Belgaum and Bijapur districts.  The main crops suggested for the cultivation under the conjunctive use plan are Sugarcane, Cotton, Groundnut, Maize and Pulses.

d) Pollution Studies:

An area about 50 sq.km in and around Bhadravathi town in  Shimoga district  was studied to  assess the  ground  water quality and aquifer material  vis-a  -vis  the industries existing, agricultural practices and urbanisation. The area  is  drained  by the perennial Bhadra  river  and  the  major industries are M/s Mysore paper mill and M/s Visweshwariyah  Iron and Steel limited.

The  area  falls  in southern transition  agroclimatic  zone  and receives a mean annual rainfall of 826.3 mm. Extensive irrigation from  Bhadra reservoir and Gondi channel, which  are  constructed across the river bhadra is practiced around Bhadravthi. Premonsoon  survey was carried out in June, 1994 during which  26 dug  wells  and  17 bore wells were identified  for  water  level monitoring  and sample collection. Solely granites underlie the area.  The premonsoon water levels  ranged from 1.54 to 13.21 mbgl and post monsoon  water levels ranged from 1.16 to 9.88 mbgl and the seasonal fluctuation (1994-95) ranged from 0.16 to 5.60 m.

A  total of 44 water samples, 20 no from dugwells, 21 from  bore wells,  2 from Bhadra river and 1 from municipal water supply  in two  sets  were collected during pre-monsoon 1994.  One  set  was analysed  in SWR office for 13 parameters and the other  set  has been  sent  to  Kerala region, CGWB,Trivandrum  for  heavy  metal analysis.

During  post monsoon 1994, a total of 47 water samples were  col­lected  in 3 sets. Sources of sampling was 21 from  dugwells,  18 from  bore  wells, 2 from river Bhadra, 1  from  Municipal  water supply, 1 from canal and 4 no.s from effluent samples. One set of samples  were analysed in SWR office, one set was sent to  Kerala region,  Trivendrum  for heavy metal analysis and third  set  was submitted to Sriram institute for industrial research,  Bangalore for analysing selected parameters.

The  key wells were got surveyed to determine (1)reduced  levels of  ground water levels to know flow direction and (2) to  estab­lish  the relationship of river Bhadra with the ground  water  in the area. The study shows that elevation of W.T lies between  565 to 611 m above sea level and the river Bhadra in this section  is effluent  in  nature and receives water from  surrounding  ground water reservoir.

In addition to the above Ground Water pollution studies were carried out in Mangalore city industrial pockets in Baikampadi area including land fills study in Mangalore town, industrial town limit of Dvanagere Municipality around industrial establishment, Industrial pockets around Banglore Metro area etc., Apart from this inland salinity and Coastal salinity in  parts of Dharwar and Udupi districts were carried out by the Board.

7. ASSISTANCE TO STATE GOVERNMENT AND SEMI GOVERNMENT ORGANISATIONS, PUBLIC SECTOR UNDERTAKINGS INCLUDING TECHNOLOGY MISSION FOR RURAL WATER SUPPLY

            Under Technology mission for rural water supply, investigation  to locate  source point for 365 identified problem villages in  Gul­barga  district, 107 in Dharwar and 76 in Raichur  districts  were completed. Other than technology mission source finding in  hard­core/problematic  villages were taken in the areas of  investiga­tion.  So  far 406 villages were covered.  In  addition  accorded technical  clearance in 13 villages for construction of nalla  and contour  bunds  and recommended sites for 6  villages  for  water conservation  work  under Jawahar Rozgar Yojana in  mini  mission areas  in Raichur district. Coordinated with various state  Govt. agencies in formulation of schemes, projects etc.

8. URBAN HYDROGEOLOGICAL STUDY

    Urban Hydrogeological study has been taken up in Bangalore Metro area, Hubli-Dharwar coporation, Mysore city corporation and Mangalore city corporation.    

8. HYDROLOGY PROJECT

Under the World  Bank assisted hydrology Project constructed piezometers for continuous  monitoring of  ground water levels  using digital water level recorders were taken up. CGWB along with MGD,  Govt.of  Karnataka have drawn a plan to construct 805 Piezometers in Karnataka.  The CGWB participation involves analysis of NHS for water  level  and water quality data.  The  basis for selection of sites for  the  piezometers construction is as follows.

a. Topography

b. Hydrogeological condition

c. Optimisation study for PZ density location

d. Depth of existing NHS location

e. Water level changes over a period of time.

f. Dark and grey blocks

g. Agroclimatic conditions.

h. Quality considerations in respect of fluoride and nitrate.

Based  on the analysis of historical data of water levels the optimum number of  observa­tion station decided for CGWB in Karnataka is 310. In Karnataka, under Hydrology Project, 367 piezometers were constructed.

9. PREPARATION AND ISSUANCE OF  VARIOUS REPORTS AND MAPS.

(i)                 Reports  summarising  the results of investigations  for  all  the districts

(ii)               Action plan for development of Ground water in  drought prone  districts of Dharwar, Kolar, Bangalore, Belgaum,  Bijapur, Raichur,  Bidar, Tumkur, Gulbarga, Chitradurga, Bellary,  Mandya, and  Tribal  districts of South Kanara,  and  Kodagu

(iii)             Basin  reports  for West flowing  river, Malaprabha river,   Cauvery and Palar river

(iv)             Hydrogeological  conditions  in the state

(v)               Report detailing the master plan for the develop­ment  of ground water

(vi)             Geo­physical survey report pertaining to Raichur and Kolar  districts

(vii)           Action  plan for augmentation  of  Artificial  Recharge studies  in Devanahalli/Hoskote taluks of Bangalore district

(viii)         Silver jubilee report of NHS in  Karnataka

(ix)             Ground water Atlas Karnataka

(x)               Hydrogeological and reappraisal survey reports

(xi)             Water  supply investigation reports

(xii)           Basic  data reports   of   exploratory borewells  drilled   under   VRBP and Southwestern region and Goa

(xiii)         State report (revised) incorporating  net­work  stations data upto 1999

(xiv)          Decennial report titled  "Beha­viour  of Ground water levels and quality in  Karnataka  1979-88"

(xv)            Karanataka atlas

(xvi)          Master plan of Goa

(xvii)        Exploration report of Karnataka and Goa.

(xviii)      Report on experimental artificial recharge studies, Kolar district.

(xix)          Ground Water year books.

10. HIGHLIGHTS

v     The Canadian Assisted Ground water project studies carried out in  Gulbarga and Bidar districts have indicated  feasibility  for sinking 980 additional borewells of which 57 wells are in granit­ic  terrain  and  923 wells are in basaltic  terrain  capable  of creating an additional irrigation potential of about 2500 ha.

v     The project studies in Vedavathi River Basin have revealed the exploitable  ground water reserve of the order of  1948  MCM.This would  support an additional number of 30,000  wells.The  optimum depth for the dug cam bore wells and bore wells have been  worked out to be 30 - 40 metres and 50- 60 meters respectively. The feasible areas for the additional wells have been  delineated in which well siting has to be done on scientific basis consider­ing the complex hydrogeological set up of the project areas.  The sea  pumping  rate of different areas have been  worked  out.  An additional  area of 1,00,000 ha. can be brought under  irrigation through the above additional wells.

v     In the Kaladgi formations dug wells are appropriate except  in the  Karstified(Cavernous)  limestone as in  Lokapur  -  Bagalkot valley  (Bijapur district). These horizontally  bedded  formations are  poor aquifers and bore wells are found to be failure.  Areas feasible  for high capacity bore wells (over 30000 lph) have  been demarcated  in  parts  of  Bagalkot,  Bilgi,  Badami,  and  Mudhol taluks. Also  Borewells are more suitable  in the proved  tectonic zones to tap the deeper aquifers. Shallow tube wells are feasible in Kulgeri - Badami valley along the abandoned channels.

v     In  Bhima basin ground water development should  be  confined chiefly  to the disturbed zone by means of borewells and dug  cum bore wells.

v     Brochures and attributes on ground water in local langauage (kannada) were prepared and distributed to various state agencies during mass Awareness Programmes held at various taluks/district head quarters and filed areas.

v     Work shop organised under Hydrology project for transfer of Technology.

v     Officers got training at different  occasions in various disciplines like hydrogeology, hydrochemistry and remote sensing , geophysics, computers etc.

v     Induction leveL Training programme was conducted at Bangalore during 2001-02.  

Click here to see the table

 

STATUS OF EXPLORATORY WELLS HANDING OVER / TAKENOVER BY STATE                                                                                   GOVT. AGENCIES IN KARNATAKA  (AS ON 31.03.2003)
Sl.No.	District	No.of Sucessful	Exploratory Wells	Wells Takenover	Wells Yet be	Exploratory	Wells Taken	Wells Kept	Balance Yet
		Exploratory wells	Offered&Handedover	by Govt.of	Taken over by	wells found	over & received	for Moni-	be Handedover
		Drilled by CGWB	by CGWB to Govt.	Karnataka	Govt.of Karnataka	Defunct.	for Current	toring purpose	to State Govt.
		in Karnataka	of Karnataka				month
1	2	3	4	5	6	7	8	9	10
1	Bangalore	40	40	13	24	3	--	--	--
2	Belgaum	54	54	12	24	18	--	--	--
3	Bellary	59	59	19	28	9	--	3	--
4	Bidar	20	20	--	14	6	--	--	--
5	Bijapur	66	66	26	18	22	--	--	--
6	Chickmaglur	30	30	26	3	1	--	--	--
7	Chitradurga	42	42	25	14	3	--	--	--
8	Dharwad	71	71	38	28	5	--	--	--
9	Gulbarga	64	64	13	29	22	--	--	--
10	Hassan	28	28	2	25	1	--	--	--
11	Kodagu	13	13	--	12	1	--	--	--
12	Kolar	34	34	1	26	7	--	--	--
13	Mandya	19	19	16	2	1	--	--	--
14	Mysore	52	52	34	17	1	--	--	--
15	S.Kanara	43	43	12	27	4	--	--	--
16	Tumkur	57	57	27	24	6	2	--	--
17	N.Kanara	5	5	1	4	--	--	--	--
18	Raichur	59	59	--	37	22	--	--	--
19	Shimoga	25	25	24	1	--	1	--	--
									--
	Total	781	781	289	357	132	3	3	--

Annexure-II

           Status of function of Chemical instruments in South Western Regional Office