四川雷波马湖水生态环境现状和保护对策OACSTPCD

Mahu Lake is the third largest natural plateau lake in Sichuan Province,which is on a par with Qionghai Lake and Lugu Lake.In order to explore the current water ecological environment of Mahu Lake,the water quality,pollution sources and water ecological environment risks of Mahu Basin were analyzed,and protection measures were put forward.The results showed that the water quality of Mahu Basin was generally good,and the water quality in the north and middle of the lake was better than that in the south.The comprehensive trophic level index(TLI)value of the lake water was 26.24 on average.The phytoplankton community was dominated by Cyanophyta,Bacillariophyta,Chlorophyta,and Cryptophyta.The cell density was 4.89 × 105～8.99 × 105 cells/L,and the concentration of chlorophyll a was less than 3 μg/L,indicating that Mahu Lake was in an oligotrophic state and the water was quite clean.The source inventory analysis revealed that agricultural planting was the main pollution source in the basin,and the total pollutant emissions was 42.1 t/a for chemical oxygen demand,6.8 t/a for ammonia nitrogen,78.1 t/a for total nitrogen and 3.3 t/a for total phosphorus.In general,the inflow rivers in the southern part of the lake were the main input route of pollution to Mahu Lake,and the water in the lake had a good purification effect on the pollutants.However,the continuous development of tourism in the Mahu Scenic Area would intensify the pressure of water ecological environment in the basin.Therefore,in order to strengthen the protection and management of the good water body in Mahu Lake,we should take the planning as the guide,promote the division of water ecological functional zones,and improve the management level of the whole basin.