Environmental conditions
The average values of environmental conditions at four sampling
stations are showedinFig. 2. There was a clear variationinthese
nine environmental variables among four stations. For example,the
average values of transparency and DO represented an increasing
trend, while those of NH4-N showed a clear decreasing trend from
station A to D. The concentrations of NO3-N and SPR were low at
stations C and D, and high at stations A and B