The spatial characteristics of precipitation and water-logging disaster during rainy season for urban planning in Xi'an

This paper provides a spatial distribution characteristic of precipitation and water-logging disaster in Xi'an based on hourly precipitation at 23 automatic meteorological observatory stations and water-logging information from 2009 to 2015. The overall spatial distribution of precipitation and intensity is higher and stronger in the north and south of the city but weaker and less in the east and west. The peak precipitation in the south and north appears at 18:00, while in the north also at 20:00-21:00. There is no obvious diurnal variation in the precipitation in the east and west, and higher precipitation frequency was recorded in the east. The water-logging frequency is highest in the Baqiao District, but the water-logged area and depth are smaller and shallower. The water-logged areas are largest in Yanta, Xinchen and Beilin Districts, where frequency is less and the water are shallow. There are more water-logged sites in Lianhu and Weiyang Districts than in other regions. Precipitation intensity and underlying surface properties are the main two factors for water-logging. By using Shanghai Urban Flooding Assessment Model, the area, depth and location of water-logging were simulated through inputting the different magnitude hourly precipitation. The guidance information provided by this paper could help city planning to provide a long-term water-logging disaster management in Xi'an.