上海肩负着建设“四个中心”的重任，同时又面临着众多的发展瓶颈，其中土地资源的短缺是制约上海发展的重要因素。横沙岛是一个集“区位、土地、岸线、航道”等众多优势资源于一身的区域，其可成陆的土地面积约为480 km2，可形成的岸线近100 km，同时利用其东侧直接面向大海的优势，有建设深水大港的条件。横沙新城的建设即可突破城市瓶颈，再造第二个“浦东”，为未来上海的发展提供广阔空间。

The natural evolution pattern of the Yangtze estuary was changed by human activities. The estuary is not controlled by the sides' cape as it did in the past. In the middle of the estuary, a beaded island chain was formed by the Changxing Island, the Jiuduansha mudflat, the Hengsha Island and the Hengsha east shoal, and a new sub estuarine delta is coming into being. This sub delta keeps expanding outward relying on the engineering constructions. The Hengsha east shoal will become land due to mudflat enclosure and siltation with waterway dredging soil. The new reclaimed land area could reach 400 km2 and more than 18 km deep-water shoreline exists along the north coast of the mudflat edge. The plenty resources of the new sub estuarine delta and an artificial island outside the estuary could become a new space for Shanghai City development and a suitable location of deep-water harbor site.