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Volume 6, Issue 4-6 February - June, 2006

CASE STUDY - 2

Water harvesting benefits who - nature or utility?

A case study of the water utility, Karnataka Water Board, Hubli

Facts and Figures
Municipal Limits of Hubli-Dharwad (as per 2001 census)
1. Population - 786,195 in 149,279 households
2.Area under - 202.28 sq km municipal limits
3.Water source for these twin cities:

  • Savadatti Reservoir, 45-65 km from Dharwad and Hubli, respectively
  • NeerSagar Reservoir, around 25 km from Hubli

Power consumed at various stages for bulk supply at a time when water supply was once in eight days:

  • Power consumed at NeerSagar reservoir:
137,880 kWh during April 2005
198,164 kWh during July 2005
149,776 kWh during June 2005
  • Power consumed at Jackwell at Savadatti:
975,360 kWh during Nov 2004
908,340 kWh during April 2005
993,510 kWh during July 2005
  • Power consumed at Amminbhavi (re-pumping):
1,342,488 kWh during Nov 2004
1,378,512 kWh during April 2005
1,521,408 kWh during July 2005
  • Total power consumed for two months:
2,424,732 kWh during April 2005
2,713,082 kWh during July 2005
  • Average power consumed: 2.7 million kWh (2,700 MW every month)
    • Add 3 MW of power load for local distribution at Hubli and 3 MW for Dharwad.
    • Total consumption for bulk pumping from the reservoir is nearly 450 times the power needed for local distribution.
  • Water consumed @ 100 liters per day per member
  • Total number of members: 786,195
  • Total consumption of water per day: 78,619,500 liters (14,348,058,750 liters a year)
At 50 percent leakage in pumping and at reserve, a minimum 28,696,117,500 liters must be stocked.

Geographical Parameters
The geographical area under the Hubli-Dharwad Municipal Corporation (HDMC) is 202.28 sq km (202,280,000 sq m).

  • Average rainfall from 1950-2000 – 738 mm; rainfall in 2001 (247 mm), 2002 (429 mm), 2003 (253 mm), 2004 (602.1 mm) and 2005 (832.12 mm till Sept 15)
  • Minimum average rainfall was 400 mm.
  • Volume of water received on the surface of the HDMC limits – 80,912,000,000 liters
  • Actual need of pure clean water – 28,696,117,500 liters (ie, 2.82 times more than the actual need, which implies one can survive for another year without rains).

    To store this huge quantity of water, one needs 80,912,000 cu m of space, which is equivalent to 6 m deep x 3,672 m wide x 3,672 m long. This must be managed in such a way that the water retention tanks are split at the various areas of natural flow. Our objective can be met if the existing – but neglected – lakes are “revived” and their water holding capacity increased. If this is achieved, the Hubli-Dharwad population would get water on a daily basis at an economical price, especially if regulated by the community itself.

    Recommendations
    The area that is currently available for water storing may not be sufficient. It will be necessary to create more checkdams at all possible run-off points. However, the cost of constructing the checkdams will be negligible compared to the amount of water that the entire Hubli-Dharwad population receives. Land can be got from the neighboring villages. Such villages also get clean purified water. Support from all quarters, more from the utility, is the necessary. A saving of 2,700 MW every month is worth the efforts keeping in view the growth in demand, population and the capital investment.

    Caution
    This harvested rainwater in the lakes will be contaminated by gutka and flow from drains and sewers. However, such contamination is applicable to existing reservoirs, as well, which is minimal owing to the large catchment area. Since the area under consideration is urban, and the contaminants accumulate (concentration) in large quantities, it is suggested that the water be treated by natural purifying agents such as water hyacinths and related aquatic plants. The water so treated can then be opened out to the lakes.

    A second concern is to build public utility toilets and regulate people against defecating in the open. Unless basic amenities are provided, the concept of community-based rainwater harvesting will remain a myth. People at all levelsmust be educated on water management.

    Availability of water is directly linked to global warming. As we use lesser energy to pump water, there will be lesser impact on the global climate.

    Courtesy: Mallikarjun Kambalyal, Sunshubh Renewable Energy Foundation, Karnataka. Tel: +91-836-5567505, 9243283505(M), Email:mallu_solar@yahoo.co.uk


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