The rice fields of Shicha sea water surface in the middle of the Ming Dynasty increased and the lake surface decreased sharply. In the southeast of Desheng Bridge, a channel for the river that leads directly to the lower reaches of the water was excavated, separated from the Houhai. The water in the pool was directly connected from the Chahe to the Qianhai. The south and west pressure gates entered the imperial city, and at the same time went northwest, crossing the Yinxu Bridge into the Houhai. Form a landscape of "silver view of the landscape backflow".