FLOOD pptx in geology..flood and it's types and it's mitigation

This presentation is based on flood and types of flood

1. FLOOD Presented by :- HARIHAR NAYAK B.Sc 5 th sem

2. What is flood..? Sometimes a water resource (river, lake or pond) gets flushed with too much water. Unusually heavy rain sometimes causes floods. When there is too much water, it may overflow beyond its normal limits. This water then spreads over land, flooding it . Extreme flooding can also be caused by a tsunami or a large storm that causes a storm surge.

3. TYPES OF FLOOD Flash flood River flood Coastal flood Urban flood

4. Flash floods Flash floods happen in a short time, they have great volume of water, and are local flood. The runoff of intense rain results in high flood waves . Flash floods result in failure of dams and more . It usually happens in desert areas and mountain regions.

5. River floods River floods are caused by melting of snow and precipitation over large areas. They take place in rivers. Floods in large rivers take hours to days . The ground conditions effects the runoff.

6. Coastal Floods Coastal floods are caused by tides, storms, tropical cyclones, or tsunamis . They happen in the ocean and effects the general public and maritime interests along the coastline . They are caused by heavy surf, tidal piling, and storm surges. Other factors are tidal cycles, behaviors of the storm, river or stream runoff, no offshore reefs or other barriers, and high winds.

7. Urban Floods Urban floods are when the land is turned --fields or woods into roads and parking lot Since this happens it can't absorb the rainfall. During the urban floods all the streets become rivers and basements become full of water, they are death traps . Ice Jam is floating ice that adds up at a man-made or natural area and stops the flow of water. This causes the area to flood.

8. Causes of flood Rains Each time there are more rains than the drainage system can take, there can be floods. Sometimes is heavy rain for a very short period that result in floods. In other times, there may be light rain for many days and weeks and can also result in floods . River overflow Rivers can overflow their banks to cause flooding. This happens when there is more water upstream than usual, and as it flows downstream to the adjacent low-lying areas (also called a floodplain), there is a burst and water gets into the land.

9. Strong winds in coastal areas Sea water can be carried by massive winds a hurricanes onto dry coastal lands and cause flooding. Sometimes this is made worse if the winds carry rains themselves. Sometimes water from the sea resulting from a tsunami can flow inland to cause damage. Dam breaking Dams are man-made blocks mounted to hold water flowing down from a highland. The power in the water is used to turn propellers to generate electricity. Sometimes, too much water held up in the dam can cause it to break and overflow the area. Excess water can also be intentionally released from the dam to prevent it from breaking and that can also cause floods.

10. Ice and snow-melts In many cold regions, heavy snow over the winter usually stays un-melted for sometime. There are also mountains that have ice on top of them. Sometimes the ice suddenly melts when the temperature rises, resulting in massive movement of water into places that are usually dry. This is usually called a snowmelt flood .

11. FLOOD IMPACT Human Loss Property Loss Affects the Major Roads Disruption of Air/Train/Bus services Spread of Water-borne Communicable Diseases Communication Breakdown Electricity Supply Cut off Economic and Social Disruption Increase in Air / Water Pollution

12. FLOODS BENEFITS Floods (in particular more frequent or smaller floods) can also bring many benefits, such as Recharging ground water , Making soil more fertile and increasing nutrients in some soils . Flood waters provide much needed water resources in arid and semi-arid regions where precipitation can be very unevenly distributed throughout the year . Freshwater floods particularly play an important role in maintaining ecosystems . Flooding can spread nutrients to lakes and rivers, which can lead to increased biomass and improved fisheries for a few years.

13. Preventing flood Sea / Coastal D efence Walls Sea walls and tide gates have been built in some places to prevent tidal waves from pushing the waters up ashore. In some areas too, sand bags are made and placed in strategic areas to retain floodwaters.

14. Town planning

15. Retaining walls In some places, retaining walls levees, lak dams, reservoirs or retention ponds have constructed to hold extra water during times of flooding.

16. Vegetation Trees, shrubs and grass help protect the I from erosion by moving water. People in lying areas must be encouraged to use a lot of vegetation to help break the power of moving flood water and also help reduce erosion.

17. E ducation Education is very important, to inform an caution people about the dangers of flood what causes floods, and what can be done to minimize its impact.

18. Flood prone zones, Areas in india

19. West Bengal Odisha Andhra P radesh Kerala Assam Bihar Gujarat Uttar Pradesh Haryana Punjab

20. THANK YOU