Groundwater Crisis in Karnataka’s Hard Rock Region
### 🧭 Context
* Karnataka, especially the Deccan Plateau region, is experiencing severe groundwater depletion.
* The Upper Arkavathy watershed (near Bengaluru) is a case study showing how intensive borewell usage and unsustainable agriculture have disrupted local hydrology.
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## 🔑 Relevant Points
### 1. 🪨 Geological Background
* The Deccan Plateau is dominated by hard rock aquifers (granite, basalt).
* These aquifers:
* Have low porosity and limited storage capacity.
* Depend on narrow fractures and weathered zones for water movement.
* Recharge slowly and unpredictably.
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### 2. 🚱 Crisis in Upper Arkavathy
* Farmers drill deep borewells into granite bedrock, causing:
* Microfractures that push rainwater deep underground.
* Bypassing of shallow aquifers, leading to disruption of natural recharge.
* Water table is dropping annually.
* Avg. borewell depth rose from 183m (2001–11) to 321m (2011–21).
* 70% of drinking water borewells failed within a decade.
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### 3. 🌊 Hydrological Disruption
* Deep borewell drilling changes the subsurface water pathways.
* Traditional recharge systems like lakes and tanks have been neglected or encroached.
* In Aralumallige, even in years of high rainfall, lakes remain dry due to lack of recharge.
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### 4. 💰 Economic and Social Impact
* Borewells cost ₹4–5 lakh each — a huge burden for small farmers.
* Electricity is free, but panchayats are in electrical debt due to high pumping costs.
* Revenue is diverted from development to cover power bills.
* Migration from villages is increasing due to:
* Borewell failures.
* Unsustainable farming.
* Rising input costs.
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### 5. 🚨 Water Quality Issues
* Nitrate and fluoride contamination found in some wells.
* However, major cause of abandonment is not pollution, but groundwater exhaustion.
* 79 wells abandoned, only 2 due to water quality.
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### 6. ⚠️ Policy and Governance Gaps
* Programmes like:
* Sujala Project (groundwater recharge)
* Jal Jeevan Mission (rural piped water)
* Have created infrastructure, but ignore root causes:
* Over-extraction
* Lack of sustainable cropping
* Weak panchayat finances
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### 7. ✅ Recommendations from Study
| Recommendation | Details |
| ————————– | ——————————————————- |
| 💧 Recharge infrastructure | Must be scientifically designed to restore aquifers |
| 🌾 Shift cropping patterns | Move away from water-intensive farming |
| ⚡ Farmer incentives | Pay farmers to use less water and electricity |
| 🏛️ Strengthen panchayats | Improve financial health and autonomy |
| 📊 Local data systems | Build village-level groundwater monitoring |
| 📚 Farmer education | Promote awareness on long-term impacts of overuse |
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### 📌 Prelims Pointers
> Q. The term “hard rock aquifer” recently seen in news refers to:
> (a) Aquifers formed in glacial deposits
> (b) Aquifers with high porosity and permeability
> (c) Aquifers found in igneous/metamorphic rock with limited water storage
> (d) Coastal aquifers with saline intrusion
✅ Answer: (c) Aquifers found in igneous/metamorphic rock with limited water storage
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