突发地质灾害过程洱海流域水质变化研究

Study on Changes of Water Quality in the Erhai Lake River Basin During Sudden Geological Disasters

洱海是云南省第二大高原淡水湖,是国家重点保护的水域之一。分析了漾濞县“5·21”M_(s)6.4地震及洱源县“9·13”大型山洪泥石流期间,洱海重点区域水质的加密监测数据并对比了突发地质灾害前后的监测数据。研究发现:M_(s)6.4地震后主要表现为总磷(TP)浓度增加,继而引发叶绿素a(Chl.a)浓度的升高,同时地震震感强烈浊度变大但并未对透明度带来影响;洱源县大型山洪泥石流,雨水冲刷水量突增造成总氮、总磷、化学需氧量、氨氮浓度急剧升高,虽在后续监测中4个监测指标均已回落,但4个交界断面和北三江入湖口9月份的负荷数据中显示,氨氮负荷增加明显,分别为19.07%、58.86%,对洱海水质(特别是北三江附近)的水生态环境带来明显影响。研究旨在探索突发地质灾害过程洱海流域水质的变化情况,为水质保卫工作积累治理经验,为洱海流域生态环境的保护提供助益。

Erhai Lake is the second largest plateau freshwater lake in Yunnan Province and one of the national key protected waters.This paper analyzed the encrypted monitoring data of water quality in key areas of Erhai Lake during the period of the "5·21" M_(s)6.4 earthquake in Yangbi County and the "9·13" massive mudslide in Eryuan County and compared the monitoring data before and after the sudden geological disaster.It was found that the M_(s)6.4 earthquake mainly increased the concentration of Total Phosphorus(TP),and then caused the increase of the concentration of Chlorophyll a(Chl.a).At the same time,the earthquake was felt strongly and the turbidity increased but did not affect the transparency,and the concentration of Total Nitrogen(TN),Total Phosphorus(TP),Chemical Oxygen Demand and Ammonia Nitrogen increased sharply due to the sudden increase in the amount of water washed away by the massive mudslide in Eryuany County.Although the four monitoring indicators have all dropped in the follow-up monitoring,the load data for September at the four boundary sections and the Beisanjiang Lake Inlet show that the ammonia nitrogen load increased significantly,at 19.07% and 58.86%,respectively,which has a significant impact on the water quality of Erhai Lake,particularly around the Beisanjiang River.The purpose of this study is to explore the change of water quality in Erhai basin during sudden geological disasters,accumulate treatment experience for water quality protection,and provide benefits for the protection of ecological environment in Erhai basin.