Hahnoi Center Case Study

A STUDY ON APPLICATION OF HARVESTING TANK FOR REUSING RAINWATER AND TO FLOOD MITIGATION

I. Introduction

Hanoi city which is on the North of Vietnam, is a capital, economy center and home to everyone from all over Vietnam. Accompanying the development of Vietnam, Hanoi city is broader and more developing day by day. However, because of fast development, Hanoi city is facing up to the fast rising of urbanization and unbalance causing many problems. Typically, there are two problems in Hanoi which are water shortage and flood. Because of the fast urbanization, there are many impervious areas and the drainage systems are overload when the permeable areas are decreasing and disappearing. Otherwise, Hanoi is being affected by underground water exploitation that causes the subsidence issue. Therefore in the rainy season, Hanoi is always in flooding situation. Moreover, the fast rising of population in Hanoi causes the unbalance of water usage. Although water treatment plants always work with fully power, in somewhere near Hanoi center, the water shortage problem still exists. Both of problems happen in rainy season when the rainfall rating is

The entire process is repeated for each sub-watershed and is modeled by two equations, continuity equation (8) and Manning?s equation (9), (8) (9) where is volume of water on the sub-watershed(m3), is area of the sub-watershed (m2), is depth of water on sub-watershed (m), is rainfall excess (mm/h), is runoff flow rate from the sub-watershed (m3/h), is depth of maximum depression storage (m), is width of flow over the sub-watershed (m), is slope of the sub-watershed (m). Fig 5. Level-surface