Groundwater management and planning for siwane sub - basin in Hazaribagh district, Bihar


Sustainable Development of Groundwater
  1. Dugwell
    Based on water-table, depth of weathered material & its saturation, generalised yield prospects and analysis of hydro-geophysical parameters at depth of 11m helped in identifying the area most suitable ( 1346.00 ha. i.e. 6.36 per cent of sub-basin), suitable ( 4666.40 ha., 22.05 per cent ), marginally suitable ( 4298.20 ha., 20.30 per cent of the sub-basin ) and area not suitable( 9053.80 ha., 42.80 per cent ) for groundwater development through dugwell ( Fig. 2 & Table - 1 ) . Most suitable zone is a area where large scale dugwell development is possible without adversely affecting the regional groundwater resources. In the suitable area stress should be given on development surface water harvesting structures besides development of groundwater. Similarly in marginally suitable area more stress should be given on development & utilisation of surface water resource and groundwater development should be given lowest priority. Similarly in the area not suitable for groundwater development, stress should be given for 100 per cent utilisation of surface water. This zone can also act as recharge zone in regional perspective.

    Table - 1: Feasibility for Dugwell Development
    Category Lapasiya Watershed (ha.) Churchu Watershed (ha.) Alaunja Watershed (ha.) Total to sub-basin (ha.) Per cent
    Most Suitable zone 1203.70 0100.00 0042.20 1345.90 06.36
    Suitable zone 1612.00 3000.00 0054.37 4666.40 22.05
    Marginally suitable zone 0820.30 1582.00 1895.93 4298.20 20.31
    Not suitable zone 3036.80 3000.00 3017.00 9053.80 42.80
    Data gap 1791.52 - - 1791.52 08.46


  2. Dug-cum-borewell
    Similarly area suitable for dugwell cum borewell has been identified which has been further cateogrised into different prospect zone ( Fig. 3 & Table - 2 ) i.e. most suitable ( 664.30 ha., 3.08 per cent ), suitable ( 5446.50 ha., 25.33 per cent ) and not suitable zone ( 13652.90 ha., 63.28 per cent ). The development as per feasibility map will reduce the chance of over exploitation of groundwater in area where aquifer is not suitable for dugwell cum borewell development.

    Table - 2: Feasibility for Dugwell cum Borewell Deveopment
    Category Lapasiya Watershed (ha.) Churchu Watershed (ha.) Alaunja Watershed (ha.) Total to sub-basin (ha.) Per cent
    Most Suitable zone 0510.50 0110.50 0043.30 00664.30 03.08
    Suitable zone 3383.80 1251.70 0830.00 05465.50 25.33
    Marginally suitable zone - - - - -
    Not suitable zone 2778.50 6247.40 4627.00 13652.90 63.28
    Data gap 1791.52     01791.52 08.46


  3. Deep borewell
    Based on DBTM and hydro-geophysical parameters, total 28 deep borewell sites have been identified which is supposed to provide sustainable yield without affecting the regional groundwater environment. Most of the sites are located in the broader fracture zones or in the sub-surface basins where high recharge to the aquifer is expected.
Groundwater Development and Management Possibility
In the entire Siwane sub-basin ( 19672 ha ), 2006 ha.m replenished utilisable groundwater reserves are available out of which a sum of 867 ha.m is already utilised for domestic need and providing irrigation to the rabi crops ( Table - 3 ) . The remaining groundwater reserve has potential to provide irrigation to 2278 ha ( 16 per cent ) area of sub-basin. Besides that huge amount ( 4061 ha. m ) of groundwater reserves lies below the existing dugwell depth ( i.e. 10 m b.g.l. ) and basement surface. This untapped groundwater reserve has potential to irrigated 10152 ha. ( 44 percent ) land of the sub-basin ( Table - 3 ). But this untapped groundwater reserves can only be utilised when suitable recharge mechanism will be developed for balancing the intake and outtake from the aquifer.

Table - 3: Groundwater Reserve Estimation
Lapasiya watershed Churchu watershed Alaunja watershed
A Area of watershed ( ha ), (under consideration) 6672 7500 5500
B Aquifer effective porosity / specific yield (per cent) 2.50 2.86 3.00
C Replenished groundwater reserve ( ha. m ) 800 900 660
D Utilisable groundwater reserves ( ha. m ) 680 765 561
E Drinking Water Requirement ( ha. m ) 69 72 43
F Existing utilisation of groundwater for irrigation purposes 252 274 158
G Unutilised groundwater reserves 359 419 360
H Irrigation potential of un-utilised groundwater reserves (ha) 718 838 720
H.1 Volume of aquifer material between two extreme of water table i.e. 5 - 10 m b.g.l. ( ha. m. ) 37600 35269 25589
H.2 Volume of aquifer material below 10 m b.g.l up to basement surface ( ha. m ) 88546 41362 22171
H.3 Utilisable groundwater reserve lying between 10 m b.g.l. up to basement surface ( ha. m ) 2214 1182 665
H.4 Irrigation potential of available groundwater reserves below the 10 m b.g.l ( ha ) 5535 2364 1330


Prioritisation of Groundwater Developments and Management
It has been observed that all the three watershed under consideration have different groundwater development potential. The Lapasiya watershed located in the upper portion of the Siwane sub-basin, have greater potential for development and utilisation of groundwater in comparision to the other watershed. Lower reaches Alaunja watershed has lowest potential for groundwater development. Therefore highest priority for groundwater development and management should be given to Lapasiya watershed, and there after Churchu and Alaunja watershed. Groundwater development and utilisation in Churchu and Alaunja watershed should be carried out strictly according to the feasibility map prepared for large scale development of dugwell and dugwell cum borewell. Keeping in view of the expected over utilisation and its consequence on the groundwater environment, surface water harvesting structures sites have been planned in such a manner that it will also contribute to groundwater recharge.

Research Gaps and Future Line of Research
Present natural recharge estimation based on National Ground Water Estimate Committee of CGWB are not providing realistic picture.There is need for site specific natural recharge estimation. Representative sites may be located on the basis of remotely sensed data. Measurement in each hydro-geomorphic unit is required to get better results.

Geophysical electrical resistivity technique may further be refined for estimating the site specific aquifer porosity and yield estimation.

In present study groundwater reserve has been estimated on the basis of total average porosity. Estimation can further be improved if site specific porosity data will be incorporated in the calculation.





Groundwater losses due to seepage in unconfined aquifer system of hard rock needs attention.
There is need for field level experimentation for knowing the relation between artificial recharge process and sub-surface basins derived from DBTM.

There is need for developing dynamic groundwater model for predicting and forecasting the groundwater environment under changing intake and out take from the aquifer. For this purpose huge database on different parameters are required i.e. porosity, permeability, yield, rainfall, recharge, flow, seepage, withdrawal, aquifer geometry etc. DBTM may be used as one of important inputs to the Dynamic Groundwater Model.

References
  • AIS & LUS ( 1988 ). Watershed Atlas of India, All India Soil and Land Use Survey, New Delhi.
  • Athawale R. N. ( 1984 ). Nuclear tracer techniques for measurement of natural recharge in hard rock terrains. Proc. Int. Workshop on Rural Hydrogeology and Hydraulic in Fissured Basement Zones held at University of Roorkee, pp 71-80.
  • Bhattacharya B. B. ( 1990 ). Hydrogeology and Groundwater Resources of Hazaribagh District, Bihar. Unpublished Report, CGWB, Eastern Region, Calcutta.
  • Karnath K. R. ( 1994 ). Groundwater assessement, development and management, Tata McGraw Hill Publishing Company Limited, New Delhi.
  • Kumar Ashok ( 1997 ). Natural Resource Management for Sustainable Utilisation and Management of Water Resources in Siwane sub-basin, Hazaribagh, Bihar, DST Project Report ( ES/011/212/95 ), BCST, Patna.
  • Kumar Ashok, Sinha Ranjan and Prasad B. B. ( 1997 ). Digital Basement Terrain Modeling ( DBTM ) - A tool for sustainable utilisation and management of groundwater in hard rock area. National conference on emerging trends in development of sustainable groundwater sources held at Hyderabad from Aug. 17-28. JNTU.
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