Introduction

One of the major causes of water environment pollution in the Three Gorges Reservoir Region is the non-standard vessel sewage treatment and discharge to the Yangtze River. Inadequate water self-purification capacity is one of the main causes of water environment pollution in the Three Gorges Reservoir Region. The natural river channel in the Reservoir Region has become a reservoir, causing significant changes in hydrological characteristics of the main stream and many tributaries of the Yangtze River. In engineering, the mountainous city is defined on the basis of the concept of geomorphology in the geography, characterized by the geomorphology of urban land and identified based on the terrain's impact on urban environment, urban engineering technology economy and urban layout. Chongqing is the largest mountainous city in the Three Gorges Reservoir Region and also the key economic development belt in the Yangtze River basin.