Water-Related Disasters
This domain tests water-related hazards and disaster risk. Questions distinguish hazard from disaster, examine floods and droughts, and test reservoir operations, early warning and vulnerability.
Core rules
- A hazard becomes a disaster when exposure and vulnerability turn it into loss. Rainfall intensity, dam releases, embankments, land use and settlement location all shape flood risk.
- Drought is slow-onset and cumulative: rainfall deficiency, soil moisture, reservoir storage and groundwater depletion interact. Maharashtra has faced both severe drought and extreme floods in the same decade.
- Reservoir operation must follow rule curves and forecast-based releases, with downstream warning. Emergency action plans need evacuation routes and vulnerable-group lists.
Worked example
A reservoir is at 90% live storage and a forecast predicts 200 mm rain in its catchment. Operators cannot wait for the dam to fill; they pre-release within the rule curve and notify downstream villages. If they release suddenly when full, the flood peak coincides with catchment runoff. The reasoning is to create storage before the inflow peak and to separate controlled release from uncontrolled spill.
Traps
- Blaming rainfall alone while ignoring dam operation and land use.
- Treating drought as only a rainfall deficit.
- Assuming a full reservoir is always safe.
- Ignoring downstream communication during releases.