ENVIS Technical Report: 133 November 2017
http://www.iisc.ernet.in/
INTEGRATED WATERSHED MANAGEMENT FOR WATER & FOOD SECURITY IN KOLAR AND CHIKBALLAPUR DISTRICTS, KARNATAKA
http://wgbis.ces.iisc.ernet.in/energy/
    T.V. Ramachandra*         Vinay S         Bhargavi R         Bharath H. Aithal    
Energy and Wetlands Research Group, Centre for Ecological Sciences, Indian Institute of Science, Bangalore – 560012, India.
*Corresponding author: tvr@iisc.ac.in
HIGHLIGHTS
  1. Kolar and Chikaballapur districts are located in the south eastern part of Karnataka State, between 12o44’N to 13o45’N latitude and 77o12’E to 78o35’E longitude. Spatial extent of is 8213 sq.km (Chikaballapur: 4244 sq.km, Kolar: 3969 sq.km).
  2. Kolar and Chikballapur districts are located in the semi arid climatic zone, with average rainfall of 690 ± 201 mm/yr, temperature between 14.4oC (January) to 35.7oC (April).
  3. Terrain Topography varies between 595 m to 1474 m above Mean Sea Level. Slope is gentle across the plains and steep across the hill ranges. Kolar and Chikballapur together had over 4800 lakes (SOI 1:50000 topographic sheets 1970’s) encompassing an area of 45085 hectares with current water holding capacity of ~15 TMC (with silt accumulation).
  4. Population has increased from 24,45,586 (2001 census) to 28,21,506( 2011 census) at a decadal rate of 15.3%.  Population at the year 2021 is projected to be 32,53,196 persons. Considering domestic demand is about 135 lpcd, annual demand by 2021 would be ~5.27 TMC (~150 Million cubic meters).
  5. Temporal analyses of rainfall trends (based on the data of 1901 to 2015) reveals COV of 0.3 (ranges from 0.26 (Chintamani) to 0.31 (Bagepalli)).
  6. Spatio temporal analyses of rainfall trends based on 113 years of rainfall data from 70 rain gauges well distributed in these districts do not show any significant decline or increase in rainfall contrary to the claim by bureaucrats to push large scale projects (of diversions – Yettinholé, and such senseless plans) and COV (Coefficient of Variation – spatial and temporal is < 0.3)
  7. Annual water yield in Kolar is about 63.8 TMC and Chikballapur is about 65.9 TMC (Total is 129.9 TMC)
  8. Water Demand (Kolar + Chikballapur districts): 86 TMC (excess water: 54 TMC)
  9. Number of water bodies: 4380 (Kolar and Chikballapur) and majority are silted.
  10. Wasteland (unproductive barren land): 38% (higher compared to any other districts in Karnataka)
  11. Solutions to water crisis: Harvest Rainwater, Rejuvenate lakes, Watershed management, plant native samplings in the catchment, de-siltation of water bodies, good governance involving all sensible stake holders and minimize mismanagement.
  12. The sustainable option to meet the water requirements of arid regions in Karnataka is through (i) decentralized water harvesting (through tanks, ponds, lakes, etc.), (ii) rejuvenation or restoration of existing lakes/ponds, (iii) reuse of waste water, (iv) recharging groundwater resources, (v) planting native species of  grasses and tree species in the catchment (to enhance percolation of water in the catchment), (vi) implementation of soil and water conservation through micro-watershed approaches. Implementation of these location specific approaches would cost much less compared to the proposed project, which if implemented would help the section of the society involved in decision making, construction and implementation of the project.