Floods in Imphal valley : Causes, effects and preventive measures
- Part 2 -

Laishram Sherjit Singh *

Scene of Flooding in Sugunu area/Serou area on August 2 2015 :: Pix - Deepak Oinam

CAUSES OF FLOOD IN IMPHAL VALLEY AND PREVENTIVE MEASURES

India's first Prime Minister Jawaharlal Nehru believed that dams to produce power, irrigation and control flooding would be the temple of modern India. Since his days, 400 large dams have been built in India along with thousands smaller levees as well as 16000 km of river embankments but the area affected by floods has expanded from 2 million hectares to 9 million due to deforestation, poor urban drainage and other factors.(Supriyo Nandy)

Same is true for Manipur also. The causes of flood in Imphal valley includes poor urban drainage, deforestation and other factors include breaching of river banks, improper damming, sediment pollution, siltation, shallowing of river beds and lakes, heavy precipitation in catchment area, changing land-use pattern, vanishing of traditional recharging structures and water bodies .Earlier, the various lakes of Manipur, mostly located in the southern part of the valley, served as effective reservoirs of excess runoff. Most of the lakes are severely degraded in quality to the extent of complete disappearance resulting in severe curtailment of their water holding capacities.

The Action Plan of flood in Manipur consists of the following activities -

1. Declaration of Flood disaster

2. Flood Forecasting and Warning

3. Trigger mechanism

4. Response mechanism and

5. Relief

Lack of early warning system and long term plans is one of the factors that often cause problems of flood in Manipur. It multiplies the effects of flooding. The following table shows the causes and preventive measures of flood in Imphal valley.

EFFECTS OF FLOODS IN MANIPUR

The followings are the effects of floods in Imphal Valley.

1. Damages of fields and crops

2. Damages of houses and properties

3. Loss of lives

4. Transportation problems

5. Drinking water problems

6. Sanitary problems

7. Spreading of water borne diseases

8. Communication problems

9. Electricity problems

10. Damage of farms and pisiculture

11. Disturbance in education

12. Severe reduction in economy etc.

CONCLUSION

The magnitude of a natural flood produced by rain is related to the intensity and duration of rain over the catchment area, the rate at which water flows across the land surface towards the river channel and the rate of flow of water through the ground to drainage systems. Flash floods can occur in urban areas due to poor drainage facility.

The rate at which water enters river channels depends particularly on vegetation cover. Large floods occur where there is little vegetation and many soils and paved surface areas those are impervious to water. Such floods are called downstream floods because the effect of flooding increases progressively downstream. Floods produced by breaching of dams tend to be upstream floods, which are confined to more limited areas.

To minimise the effects of the flood, it is required to strengthen the river bank and deepening the river beds. Drainage facility should be improved particularly in urban areas to prevent flash floods.

Environment conservational efforts and check dams are also required to regulate the flows. Geo-engineering consideration when constructing Dams and quality control are important to minimise the flooding effects.

Making long term plans and activation of early warning system can reduce the hazard. Controlling land-use pattern and restoring traditional recharging structures and water bodies are also equally important.

Concluded...