Analysing the correlations of long-term seasonal water quality parameters, suspended solids and total dissolved solids in a shallow reservoir with meteorological factors.

To explore the correlations among water quality parameters, suspended solids (SS) and total dissolved solids (TDS) with meteorological factors in a shallow reservoir in China, the long-term variations of water quality were considered. A non-parametric regression method, generalized additive models (GAM), was used to analyse the correlations among eleven physicochemical and biological parameters as well as three meteorological factors (wind speed, rainfall and solar radiation) which we collected from 2000 to 2011. The results indicate that the three meteorological factors may have positive effects on SS. Moreover, statistically significant correlations between many water quality parameters and SS or TDS were exhibited seasonally. The correlations between electrical conductivity (EC) and SS were opposite to correlations between EC and TDS. This finding reveals that TDS have a positive impact on EC, while EC negatively affects SS. The results indicated that many parameters, such as total nitrogen, total phosphorus, biological oxygen demand (BOD) and chemical oxygen demand (COD), were related to SS due to the adsorption of SS. Moreover, both positive and negative correlations between COD and TDS were observed in this freshwater reservoir. The positive correlation between chlorophyll a and SS suggested that the change of SS concentration in autumn was caused by the growth of algae. Meanwhile, significant correlations between SS and meteorological factors were also observed, indicating that meteorological factors had effects on SS dynamics. This study provides useful information regarding the correlations among water quality parameters, SS and TDS with meteorological factors in a freshwater reservoir.