| The mixed model as a new method in the research of water quality data with multiple sites was proposed and applied in the analysis of total Nitrate-Nitrogen and total Phosphate-Phosphorus concentration data in the Truckee River, Nevada. Relatively speaking, highly populated areas tend to have higher total Nitrogen and total Phosphorus concentration. Mean concentrations above EPA recommended safe level for drinking water and eutrophication were observed. A sequence of time series exploratory analyses was used in a specific site to detect or correct the possible problems associated with time series data: missing values, outliers, trend, seasonality, non-stationarity and cycles.; The methods used in this study are sufficiently general to other similar studies. Based on the current study, suggestions and recommendations for a further study were also made. |
