The water quality state was evaluated with shannon - weaver index and some indicators of periphyton , and results showed that the nutrient type of daoguanhe rerservoir was mesotrophic type , and it had a tendency to develop to the eutrophic type 11 .依据周丛藻类多样性指数及周丛生物某些指示种类评价该水库水质状态，判定为中营养型，并有向富营养级演化的趋势。
2.
According to the modified carlson ' s trophic state index , the lake has recently been varied between oligotrophic and mesotrophic . cyanophyta , bacillariophyta and crytophyta were the superiority population in qiandao lake , but cyanophyta was the superiority population in algae bloomed month such as march , june and july 蓝藻门、硅藻门、隐藻门为千岛湖的优势种群，但在藻类爆发的5月、 6月和7月，均是蓝藻门为优势种群，优势种群与1992年比较发生了i删。
