Guwahati, the capital city of Assam and the gateway to the seven north-eastern Indian states, is located in the Brahmaputra valley—one of the most flood prone regions of the world. The city receives an average annual rainfall of 1688 mm and is highly vulnerable towards frequent urban floods because of uncontrolled dumping of solid waste and siltation have choked the natural water channels. This coupled with the absence of an integrated drainage network and rapid urbanisation causes floods in many parts of the city, after a quick downpour. Bharalu river is the main natural water channel of the city and Bharalu basin is the most vulnerable one. The present paper is an attempt to plan for urban flood mitigation, by designing an integrated drainage network for the Bharalu basin which includes the low-lying urbanized areas bordered by the Guwahati-Shillong Road, the Radha Gobindo Baruah Road and the Rajgarh Road. Data regarding land use, flood level, rainfall, urban pattern and vulnerability towards urban flood were collected from available literature, field survey to find highest water level for 11.4 km road stretch, expert opinion survey from 18 experts and feedback from 77 community elders who have been residing in the city since the 1980s. The Bharalu basin is divided into seven drainage blocks and storm run-off has been calculated based on the inputs. Seven different trapezoidal drainage sections were designed to form an integrated drainage network which is ‘self-healing’ to a certain extent. This can serve as a template for the other catchment basins and to design a drainage network for the entire Guwahati city, thereby reducing urban flood hazard to a significant extent. The study illustrates the necessity of an urban flood mitigation planning approach in sub-Himalayan urban settlements such as Guwahati.

古瓦哈提（Guwahati）是阿萨姆邦（Assam）的首府，是通往印度东北部七个州的门户，地处雅鲁藏布江谷（Brahmaputra）山谷中-世界上洪灾最易发地区之一。该城市年平均降雨量为1688毫米，极易遭受频繁的城市洪水的袭击，因为固体废物的无节制倾倒和淤积阻塞了自然水道。快速的倾盆大雨之后，再加上缺乏综合的排水网络和快速的城市化，导致该市许多地区发生洪水。巴拉鲁河是该市的主要自然水道，巴拉鲁盆地是最脆弱的河流。本文是针对城市减灾计划的尝试，通过为巴拉鲁盆地设计一个综合排水网络，包括与古瓦哈蒂-西隆路，拉达·戈宾多·巴鲁亚路和拉贾加路接壤的低洼城市化地区。从现有文献中收集有关土地利用，洪水位，降雨量，城市格局和对城市洪灾的脆弱性的数据，实地调查以找出11.4公里道路段的最高水位，18位专家的专家意见调查以及来自77位社区老人的反馈自1980年代以来一直居住在这座城市。巴拉鲁盆地被划分为七个排水区块，并根据输入数据计算了暴雨径流。设计了七个不同的梯形排水段，以形成在一定程度上“自愈”的集成排水网。这可以作为其他集水盆地的模板，并可以为整个瓜瓦哈蒂市设计一个排水网络，从而在很大程度上减少了城市洪灾的危险。这项研究表明，在诸如古瓦哈提（Guwahati）等喜马拉雅亚城市居民区，采取城市防洪减灾计划方法的必要性。