wreaking havoc on the city. if the sea level rises the most direct impact on shanghai comes from coastal waters once the maximum water level is reached and the city is flooded from heavy rain or upstream flooding the drainage system won't be able to handle the excess water. high is faced with a huge problem in cases of massive flooding all strong tides it's canals will be unable to evacuate such a surplus of water in an effort to minute. minus the damage the chinese built the barrier. to entry and. here we have a flood it's meant to prevent the one poor title waters from entering the river. plus of the normal it lies on the riverbed so it doesn't spoil the landscape it