1. Spatiotemporal Modelling of Nitrate and Phosphorus in River Catchments for England and Wales Claire Miller 1, Ana-Maria Magdalina 1, Adrian Bowman 1, Marian Scott 1, Duncan Lee 1, Robert Willows 2, Chris Burgess 2 and Linda Pope 2 1 Statistics, University of Glasgow 2 Environment Agency

2. Project Objectives To investigate the overall pattern of nutrient concentrations in river surface waters over the past 20-30 years. To investigate if the spatio-temporal distribution of nutrient concentrations in river surface waters within and between catchments can be explained by catchment covariate information.

3. Data Response: OP, TON, TN (log transformed and non-detects imputed) Covariates: Population Land use Land cover Fertilizer Physical characteristics of the land (slope, soil type and quality) Rainfall Flow/discharge Base flow index (BFI). River catchment - Large Hydrological Areas (59 units)

4. Large Hydrological Areas LHA 22 Coquet- Wansbeck Blyth

5. Additive Model Additive model to investigate temporal and spatial trends and seasonality and incorporating space-time interactions:

6. TON for Coquet, Wansbeck, Blyth LHA in the NE (1994 - 2009) The plot highlights the adjustments that should be added to the main effect for season at particular time points. trendseasonality Interaction between day and year

7. time and space interaction The movie highlights the spatial adjustments that should be added to the main effect for space at particular time points. Easting Northing Spatial Trend Interaction between space and time TON for Coquet, Wansbeck, Blyth LHA in the NE (1994 - 2009)