Abstract: Submerged plant is a key factor maintaining the clear water state of shallow lakes. The coverage of submerged plant is an important parameter of plant measures in water ecological restoration projects. By collecting the changes of submerged plants in natural shallow lakes and analyzing the research results of scholars on projects in China and abroad, we conclude that the coverage of submerged plants in shallow lakes can be ranging from 50% to 70% in design. For lakes with small pollution load, a low value of coverage of submerged plant can be taken; for ponds, the value can be at about 30%; when the concentration of nutrients exceeds threshold, the coverage should be at a high value. According to engineering experience, the higher the coverage, the better the water quality can be maintained given a constant pollution source. Besides, in view of the problems that affect the coverage of submerged plants, for example, sediment pollution, water transparency and seasonal changes, we put forward some suggestions in an attempt to provide experience and reference for the future work of submerged plant restoration in shallow lakes.

Key words: shallow lake, submerged plant, coverage, value range, water quality