The Application of UBS has to Reduce due to Influencerainfall Extreme in the A.Y Patty Street Ambon City

In the last 20 years there is often an extreme climate phenomenon that causes high rainfall and flood impact in Maluku. A.Y Patty Street is one of the locations in Ambon, the capital city of Maluku that often experience the inundation. In facing this phenomenon, the extreme value theory becomes the right solution where based on the theory, the value of extreme rainfall is known asymptotically and it will converge following the distribution of GEV (Generalized Extreme Value) which is an extreme value in a certain period.To overcome the extreme climatic problems on urban drainage system, the under drain Box Storage (UBS) filling hole is used as an environmentally friendly drainage concept. With the implementation of UBS, the drainage system can reduce 43.36% the inundation that occurred on the area of A.Y Patty street for the 5th return period and 30.99% for 10th return period.,or51.25% of the volume of water capable of being impregnated into the soil.