关于浅水湖泊沉水植物覆盖度设计依据的探讨

沉水植物是维持浅水湖泊清水态的关键因子,其覆盖度是水生态修复工程中植物措施的重要参数。从沉水植物作用机理出发,通过收集天然浅水湖泊沉水植物变迁情况,分析国内外相关学者和工程的研究成果,得出在浅水湖泊沉水植物覆盖度设计时可在50%~70%范围内取值;对于污染负荷小的湖泊,可以取相对较低的值;对于水塘,其取值可按约30%考虑;当营养盐浓度超过阈值时,覆盖度应处于较高的水平。根据工程经验,在污染源恒定的情况下,覆盖度越高,对水质可起到越好的维持效果。同时,针对影响沉水植物覆盖度的有关因素,例如底泥污染、水体透明度以及季节变化等作了思考并给出了相关建议。研究结果为今后浅水湖泊沉水植物恢复的相关工作提供一定的经验和借鉴。

Discussion on the Coverage Design of Submerged Vegetation in Shallow Lakes

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.