geology and hydrogeology of solapur city and surrounding
DESCRIPTION
It is a scientific study of Solapur city and around, to understand the geology and its relation to ground water availability,its quality and storativity. With help of Electrical resistivity - Geophysical method- attempts are made to evaluate lithological formations( Number of lava flow units) at depth, to further interpret for probable grondwater sauration depth zones.TRANSCRIPT
GEOLOGY AND HYDROGEOLOGY OF
SOLAPUR CITY AND SURROUNDING
BY
Dr. VADAGBALKAR S. K.Head, Department of Geology,
Dayanand College of Arts and Science,Solapur-413002
Maharashtra State, INDIA
Physical Map of Solapur District
Map of Solapur City with main water bodies and road links
Part of Toposheet no. 47-0
Depicting features of
Solapur City and surrounding
Satellite picture of Solapur and surrounding area
Satellite picture of Solapur and surrounding area depicting 3 river basins
480 M
480 M
480 M 480 M
460 M
460 M460 M460 M
460 M
460 M
460 M
480 M
460 M 420 M 460 M440 M
440 M
420
440 M
440
CONTOUR MAP OF SOLAPUR CITY AND SURROUNDING
OLD CITY
EKHRUK TANK
KAMBAR TANK
HOTAGI TANK
SINA RIVER
ADILA NALA
HATTUR NALA
HOTAGI NALA
Regional Geological Map Of Part Of Maharashtra including Solapur and surrounding
Geologically the area is covered by Deccan basalt of the continental tholeiitic province of India having Cretaceous - Eocene age.(about 55 to 65 million years).
Two distinct lava flows are recognized along with various flow units. The thickness of the various flow units in the lava flows vary laterally & vertically through out the city area. Surrounding the city area two more flows are identified.
Due to which the ground water availability vary. Heterogeneity in the distribution of fracture pattern, weathering mantle etc. has hindered the movement of groundwater, which has resulted in separation of water pockets of different dimensions with variable storage. There is no continuity in groundwater flow mainly at deeper depths.
Recharging of upper shallow aquifer during monsoon, takes place. As the stock/storage of water ceases after use, the groundwater availability is at stake, specially at depths.
Variation in Single Basalt Flow (schematic)Vesicular/Calcritic/Zeolitic with Horizontal(sheet) and vertical fractures with or without red bole
Compact/ MassiveWith rare or no
fractures
Compact/ Massive With some fractures with or without vesicles
Two Basalt flows separated by red bole layer
Top portion of Flow 2
(Weathered vesicular)
Bottom portion of Flow 1
(Cuboidal jointing)
Hillock representing 3 lava flows
Flow 1
Flow 2
Flow 3
Cal critic surface Representing Top of lava flow
Part of a single lava flow with small thickness weathered unit and Large thickness Massive unit
weathered unit
Massive unit
Lithological Variation
Part of stone quarry- Massive basaltPart of Columnar-Massive basalt
Lithological Variation
From Left top (clockwise)
1- Alluvium (man)
2- Spheroidal basalts
3- Calcritic sediments
4- Red bole with
weathered zeolitic
basalt
1 2
4 3
Seepage of ground water
Lithological Variation
From left top (clockwise)
1- Red bole with shattered rocks 2- Surface joints
3- Contact of two flows. 4- Sheet jointed basalt.
1 2
4 3
Vesicular- amygdaloidal basalts have horizontal sheet fractures and can store more ground waterCompact basalts have no or limited vertical/sub vertical fractures and can not store ground water but may help in movement of water at depths
Recharge to shallow ground water
Flow no. 1
Flow no. 1
Flow no. 2
In well bore
Schematic diagram for a typical dug well and in well bore conditions
Bore No. 1
Bore No. 2
Bore No. 3
Lithological section of Palas Basin
Topographic 3 dimensional computed model of Solapur city and surrounding
SouthLat. 17˚ 30’Long. 75˚ 55’
NorthLat. 17˚45’Long. 75˚ 55’
Ekrukh Tank
Main cityMajrewadi
Kumtha nala
Sina R.Sindkhed
Flow 2
Flow 3
Flow 1
Flow 4
North – South Sectional view through Solapur City and surrounding
(Schematic diagram)
Flow no. 1 - ~ 470 meters & aboveFlow no. 2 - ~ 470 meters ~ 440 metersFlow no. 3 - ~ 440 meters ~ 410 metersFlow no. 4 - ~ 410 meters & below
Flow contacts are normally found favorable for ground water occurrence at depths
WestLat. 17˚40’Long. 75˚ 45’
EastLat. 17˚40’Long. 76˚
Sina R.Tirhe
Adila nalaDegaon
Main city
N - Kumbhari
West – East Sectional view through Solapur City and surrounding
Flow 1
Flow 2
Flow 3
Flow 4
W - Shingoli
(Schematic diagram)
Flow no. 1 - ~ 470 meters & aboveFlow no. 2 - ~ 470 meters ~ 440 metersFlow no. 3 - ~ 440 meters ~ 410 metersFlow no. 4 - ~ 410 meters & below
Flow contacts are normally found favorable for ground water occurrence at depths
Groundwater as source
Solapur Municipal Corporation is one of the main body in the Maharashtra State which has successfully launched the extraction of ground water through bore wells for the public.
Mainly the bore wells are supplied with the hand pumps and very few are with electric pump. However private bore wells are generally having electric pump on large scale for pumping of ground water.
In general hand pump working is seasonal and in summer they didn’t work due to depletion of water table. However they get recharged during monsoon.
As per record of municipal corporation-
1st bore well in Solapur city – in 1975 for 150’ depth
Upto 1977 - 60 bores wells were drilled mainly in old city area.
Upto 2001 - 2195 bore wells were drilled including extended area.
In Solapur city area by electrical resistivity method, three different possible aquifer zones are investigated. The first one is shallow aquifer met at the depth of around 10 to 20 mts, or 20 to 40 mts. The second one is at deeper depths meeting at either 60 to 80mts. or 80 to 100mts. The third one is at still deeper depth of 120 to130 mts. or 140 to150 mts.
Of these the shallow aquifer is found to get recharged during regular monsoon, while the other two at depths are normally not recharged and are probably stock waters.
Reduction in percolation quantity and there by in storage due to urbanization, metallic & tarring of roads, concrete buildings, hardening and packing of grounds etc. caused depletion in ground water availability.
Earlier in 1980 and 1990’s bore wells of about 100’ depth were sufficient in general for a small unit of 5 to 6 members of family, with daily requirement of about 500 To 600 liters per day. However with present situations, bores are yielding very less water or no water or intermittently stock water if is available through weak percolation, does not full fill the needs.
However some bores are with depth of 300’ to 500’, which are tried in different areas by few individuals, contractors, and industrialist are yielding good waters. However it is found that these are having short duration and a temporary phase. The success rate of good yield of bores for relatively long duration is around 4 to 6 %..
However only 5% bores waters are considered usable for drinking purpose as per Standards i.e.95% are only usable waters.
However the individual householders / fiat owners, societies industries, commercial centers etc. have drilled bore wells in their private area as standby or as regular source mainly in extended areas where corporation filter water is not available
It is roughly estimated that probably there are total about 10,000 bore well drilled in the city area of which nearly 60% are seasonal and with low discharge (about 200 to 500 lit/day) nearly 30% are giving medium discharge (about 500 to 2000 lit /day) while nearly 10% are with high to very high discharge (more than 2000 lit /day)
As per review study it is estimated that nearly 3 MLD water is made available through groundwater resources.
Presently with consecutive drought years and more extraction of ground water more than 60% of bore wells have been modified to low to very low or no yield.
With improper casing or damage of casing mixing of sewerage water, industrial liquid waste etc. these bore waters get polluted. The maintenance of these bores is very poor or nil.
The quality of bore water is not regularly examined and no data on standards is available, though the water is used for drinking, washing, household and by many industrial sectors too.
Ground water quality is deteriorating in many parts of the city. With no regular quality check up, the bore waters are used without any information by the citizens especially in adverse situations, even for drinking purpose with out any treatment. This has produced health regards in these parts.
In different part of the city where the water are low to moderately polluted, include areas around MIDC areas and small scale hand looms & power looms & dying industries running through the residential houses and quarters mainly concentrated in eastern part of the city, the wells & bore water are polluted with traces of toxic compounds, metals & metalloids complexes.
In and around the main Shelgi nala in parts of NE, North, NW and western part of the city the wells and bore water at places are of saline in nature due to thick black soil cover and sewerage mixing.
In southern part of the city the water are relatively good but are naturally medium hard. It is an extension area, with no proper under ground drainage system. There is fear of mixing of surface drainage water with ground water and may pollute the source.