# Flood questions

Subject: Disaster Management

Exam: M2

Reader: https://deep-learning-study-room.vercel.app/dm/#m2/papers/m2-questions/floods

Canonical: https://deep-learning-study-room.vercel.app/read/dm/m2/papers/m2-questions--floods/

2-mark and 3-mark practice · full answers below each question

### Practice question. Differentiate between slow-onset floods and flash floods. [3 practice marks]

#### Answer

| Slow-onset | Flash |
| --- | --- |
| Gradual rise, often from prolonged basin rainfall. | Sudden rise, commonly after intense rainfall or dam failure. |
| Usually more time for warning and evacuation. | Often little warning time. |
| Long inundation disrupts crops and livelihoods. | Fast, debris-laden flow can cause immediate destruction. |

#### Real case and learning connection · Mumbai floods, 2005

The Mumbai flood case links intense rainfall with urban drainage and development conditions. For an answer on mitigation, explain how maintaining drainage and protecting water-storage spaces address specific pathways of flooding; do not claim that any single measure prevents every extreme event.

[Case reference ↗](https://nidm.gov.in/PDF/Newsletter/6_nov_2005.pdf)

### Practice question. Explain three causes of urban flooding and corresponding measures. [3 practice marks]

#### Answer

1. Impervious roofs and roads increase runoff; permeable surfaces and rain gardens can reduce and delay it.
2. Blocked or inadequate drains cannot carry peak flows; cleaning, capacity upgrades and connected outlets improve drainage.
3. Encroachment on wetlands and floodplains removes storage and exposes settlements; protection of these areas and risk-based land-use control reduce losses.

#### Real case and learning connection · Mumbai floods, 2005

The Mumbai flood case links intense rainfall with urban drainage and development conditions. For an answer on mitigation, explain how maintaining drainage and protecting water-storage spaces address specific pathways of flooding; do not claim that any single measure prevents every extreme event.

[Case reference ↗](https://nidm.gov.in/PDF/Newsletter/6_nov_2005.pdf)

### Practice question. Explain any three structural flood mitigation measures. [3 practice marks]

#### Answer

1. **Reservoir storage:** retain part of a flood inflow and release water in a controlled manner to lower the downstream peak.
2. **Embankments:** provide raised barriers that limit river overflow; inspection and maintenance reduce breach risk.
3. **Drainage and channel improvement:** remove blockages and bottlenecks and restore designed conveyance so excess water drains safely.

#### Real case and learning connection · Mumbai floods, 2005

The Mumbai flood case links intense rainfall with urban drainage and development conditions. For an answer on mitigation, explain how maintaining drainage and protecting water-storage spaces address specific pathways of flooding; do not claim that any single measure prevents every extreme event.

[Case reference ↗](https://nidm.gov.in/PDF/Newsletter/6_nov_2005.pdf)

### Practice question. Explain floodplain zoning and its importance. [3 practice marks]

#### Answer

Floodplain zoning divides flood-prone land according to risk and regulates permitted development.

1. It limits exposure by restricting vulnerable settlements and critical facilities in high-risk zones.
2. It preserves natural drainage and floodwater storage, reducing obstruction and encroachment.
3. It supports safer growth, evacuation planning and lower future rescue and recovery costs.

#### Real case and learning connection · Mumbai floods, 2005

The Mumbai flood case links intense rainfall with urban drainage and development conditions. For an answer on mitigation, explain how maintaining drainage and protecting water-storage spaces address specific pathways of flooding; do not claim that any single measure prevents every extreme event.

[Case reference ↗](https://nidm.gov.in/PDF/Newsletter/6_nov_2005.pdf)

### Practice question. State two beneficial and two harmful effects of floods. [2 practice marks]

#### Answer

**Benefits:** deposition of nutrient-rich sediment can improve floodplain fertility; infiltration can recharge groundwater and wetlands. **Harm:** fast or deep floodwater can cause deaths and property damage; contaminated water and disrupted services can create health and livelihood losses.

#### Real case and learning connection · Mumbai floods, 2005

The Mumbai flood case links intense rainfall with urban drainage and development conditions. For an answer on mitigation, explain how maintaining drainage and protecting water-storage spaces address specific pathways of flooding; do not claim that any single measure prevents every extreme event.

[Case reference ↗](https://nidm.gov.in/PDF/Newsletter/6_nov_2005.pdf)