Influence Of Extreme Rain On Water Quality Of Gaozhou Reservoir

In order to study the impact of extreme weather events on the water quality of Gaozhou Reservoir,the changes of long-term waterquality of the reservoir were analyzed according to the characteristics of long-term precipitation variation and long-term water quality data.The changes of precipitation and short-term water quality of Gaozhou reservoir were discussed during the typhoon rainstorms of"Fanapi"and"Mujigage".The countermeasures were put forward to provide the technology for the future regional disaster prevention and water supply security support.The main conclusions are as follow:?1?From 1953 to 2015,the precipitation in Gaozhou Reservoir showed an increasing tendency,with the average rainfall of 1780.5mm.The rainfall was mainly concentrated in the wet period,and the rainy season accounted for more than 85%of the annual rainfall.The seasonal precipitation growth rate in the catchment area was summer>winter>autumn>spring.?2?The concentrations of DO,pH,SD,Chl.a and COD_Mn in transect of the"Fanapi"Typhoon show a decreasing trend and show an increasingtendency after heavy rainfall.The content of NH₃-N,TN,TP and Feincreased with the increase of rainfall intensity,but decreased gradually after heavy rainfall.The concentrations of DO,pH and COD_Mn in the reservoir were significantly affected by heavy rainfall.The concentrations of TP were significantly affected by typhoon heavy rainfall in the river.The TP and TN contents in the bottom of the water supply surpassed the surface water?standard,and the Fe concentration in the bottom layer exceeded the standard limit of 0.3 mg/L,which seriously affected the water supply safety.?3?The conductivity,DO,pH,SD,Chl.a,NH₃-N,TN,TP and COD_Mn in the"Mujigage"show a decreasing tendency during heavy rainfall,and the trend is gradually increasing after heavy rainfall.Among them,DO,p H,NH₃-N,TN,TP and COD_Mn were significantly affected by heavy rainfall.Thedistribution of transparence showed that the river area was higher than in the reservoir area,before,during and after heavy rainfall.?4?The Eutrophication Index of the reservoir area and the river decreased,and The Eutrophication Index of the river showed higher than the reservoir area after the typhoon of "Fanapi" and "Mujigage".