Study On The Characteristics Of Phosphorus Pollution During Precipitation Runoff Process In The Second Water Drinking Source Of Fuzhou Shanzi Reservoir

Shanzi reservoir is the second drinking water source for Fuzhou city.At present, agricultural non-point pollution is one of the main reasons of the reservoir eutrophication. To explore the disciplinarian of agricultural non-point pollution taken place in the reservoir and to seek control measures,typical experimental plot was selected.By combining diagnoses with practical monitoring and model simulation,the disciplinarian of phosphorus lost by agricultural non-point pollution and estimation of phosphorus load by model was studied,then the measures of controlling phosphorus pollution occurred in rainfall runoff was put forward.Through the study work,it elicited the conclusion as follows:(1)Characteristics o f runoff in the Rainfall process:The peak of runoff lagged behind the rainfall peak 10 to 30 minutes.It showed that negative relation existed between the time of the peak of runoff lagged and rainfall intensity.The sequence of runoff from maximum to minimum is pine bamboo,paddy fields,sweet potatoes.(2)Characteristics of the phosphorus of surface layer soil lost:The level of TP and DRP lost from maximum to minimum is sweet potatoes＞paddy fields＞pine bamboo.It showed positive relation existed between that proportion of DRP account for TP and Moisture in soil.(3)Characteristics of the phosphorus output during rainfall runoff:The peak concentration of phosphorus in runoff and the peak of runoff often existed at the same time.Mainly form of phosphorus lost is particulate phosphorus.The sequence of concentration of phosphorus in runoff from maximum to minimum is sweet potatoes,pine bamboo,paddy fields.(4)The regression analysis results showed that polynomial relation existed between runoff and TP output load,and the R~2 values of pine bamboo,paddy fields and sweet potatoes were 0.9982,0.9978,0.9984,respectively.(5)It was validated that AnnAGNPS Model can be well used to simulate phosphorus load in rainfall conditions in Shanzi reservoir.The Model was applied to estimate phosphorus load in the reservoir from 1996 to 2004.The results showed that TP and DRP load was most in 1997,and was least in 2003.