Question

Question 7. Explain the three key runoff mechanism that contributes to runoff (5 marks) 17400 Engineering Hydrology End of Term Assessment Page 2 of 3 Student ID number: Question 8. Describe 5 different sources of flooding (10 marks)

Question 8 please my teachers please

Answer 1

* five different sorces of flooding are as under :-

1. river and streams :- excessive precipitation either in the form of rain, snow, hail etc. cause river and stream flooding . flooding occurs when runoff capacity of land exceeds the flow capacity of river . saturated surface soil makes the earth surface impermeable which leads to flood condition .

2. sea :- flooding form the sea can be caused by-

* high tides , for example - tsunami

* storm surges

* breaching of sea fencing

* increase in sea level.

3. ground water :- flooding from the ground water is used to in aquifers i.e limestones, chalk . this type of flooding mainly affects old buildings which have high permeability with the time or under ground structures that are prone to ground water flooding.

4. overland flow :- this problem is caused due to excess precipitation of rainfall on the saturated surface where ground water level is already high . properties can be flooded by overland flow if it is located in the region of acccumulation of flood water .

5. blocked drainage :- this type flooding is caused by blockage of drainage system which results to accumulation of water at nearby places. due to chocking passage of water becomes impossible and leads to flooding condition .