DISTRIBUTION PATTERN OF SUSPENDED PARTICULATE MATTERS IN THE LOWER REACH AND ESTUARY OF THE MINJIANG RIVER

The distribution pattern of suspended particulate matters (SPM) in the lower reach and estuary of the Minjiang River is studied in this paper.The results suggest that SPM content in the normal period of water charge ranges from 5.67 to 493.8 mg/L,with an average of 114.2 mg/L,and the content of SPM is higher at the bottom at almost all the stations.From northwest to southeast,SPM keeps an increasing trend towards the sea.A peak value appears at the bottom layer of the Guantou to Yingyu section.SPM content during the period of high-water charge is around 6.9-138.7 mg/L,with an average of 29.7mg/L.The SPM content displays a noticeable distribution pattern of middle layer > bottom > surface.From the upper reach to the sea,the concentration of suspended matters smoothly increases,without significant enrichment.Based on the data of temperature,salinity and turbidity,it is inferred that the upper and lower layer are more or less uniformly mixed during normal-water period,and there is no stratification of water.A salt wedge regime is developed in the estuary,and the turbidity maximum zone occurs in the region where salinity is around 2-5.5.According to the source and distribution of SPM,combined with its hydrodynamic environment,it is concluded that the Minjiang River Estuary turbidity maximum zone in the period of investigation belongs to the category of "marine source and tide drive".