Research On The Different Seasons Of Water Quality And The Reasons In Shibianyu Reservoir

Shibianyu reservoir is at the state of eutrophication, which resulted that the deterioration of water quality, algal blooms. It is a major problem to be solved. This study took one year on-site monitoring in Shibianyu reservoir and the rivers upstream, to analyze the different seasons of reservoir water quality, the pollution and its release in the sediments from different areas of reservoir and the anaerobic zone at different distribution water, to provide a theoretical basis for the water supply and pumping aeration algae control technology. The main conclusions are as follows:(1) Shibianyu reservoir is divided into four periods. The form of hierarchical at end of March to June; The stable stratification at the end of June to the end of August; The destruction of stratification at September to October; The water body completely mixed at the end of November to March. The maximum ammonia at bottom water reached 1.56 mg/L, it is the upper body of water 8 times. The highest TN value reached 4.21 mg/L, beyond the standard Class III surface water 4 times. TP, iron, manganese concentrations up to 0.21mg/L, 0.08mg/L, 0.4 mg/L, the content of phosphorus, manganese are 4 times, 10 times to surface water Class III. The maximum surface water pH is 10.21, while the underlying conductivity reaches a maximum of 254 μS/cm at the periods of stably stratified in Shibianyu reservoir. The other three periods other indicators of surface water to meet Class III standards in addition to the total nitrogen exceeded water quality.(2) In spring, soil upstream was frozen and a large number of nitrogen was flushed into reservoir, which led to increasing inflow and the total nitrogen( TN) of Shibianyu reservoir. The total nitrogen( TN) in the surface has reached to 6.44 mg/L. Continuous heavy rains caused upstream landslides, and a large number of sediment was flushed into the reservoir, which resulted in increasing of nitrogen and phosphorus concentration in the reservoir. The concentrations of total nitrogen( TN) and total phosphorus( TP) in hypolimnion reached to 5.42 mg/L and 0. 10 mg/L.(3) The hypolimnion becomes anaerobic in the stratified period, increasing the release of phosphorus from the bottom sediments.(4) The Continuous heavy rains caused upstream landslides, and a large number of sediment was flushed into the reservoir, which resulted in increasing of nitrogen and phosphorus concentration in the reservoir. The concentrations of total nitrogen( TN) and total phosphorus( TP) in hypolimnion reached to 5.42 mg/L and 0. 10 mg/L.(5) The pollution and its release in the sediments from different areas of reservoir has no much difference. The granularity of the sediment from S6 is 9.186 μm.The rate of consume of oxygen:S7>S6>S8.The sediment from S7 release most N、P、Mn and Fe.