Stephen Buss and Jodie Whitehead Sustainability Live 2 nd April 2014

1. Is catchment management feasible for securing good water quality public water supply from groundwater? Stephen Buss and Jodie Whitehead Sustainability Live 2nd April 2014

2. Presentation Overview Background Modelling nitrate trends Cost benefit appraisal AMP6 catchment management programme Sustainability Live, 2nd April 2014

3. Background STW manages 181 groundwater and 15 major surface water treatment works Nitrate going up all over the place 30 odd sources show rising trends (using a linear fit) Scope of study – catchment characterisation Scope of study – cost benefit appraisal What is the nitrate issue? Sustainability Live, 2nd April 2014

4. Historical Nitrate Trends NEAP-N data 2010 Change in N 1980-2010 Sustainability Live, 2nd April 2014 NEAP-N data courtesy of ADAS

5. Historical Nitrate Trends Borehole water quality data Soil loading1980 Soil loading2010 Sustainability Live, 2nd April 2014

6. Groundwater Catchments Sustainability Live, 2nd April 2014

7. Nitrate Inputs Time & Attenuation Prediction Water Nitrogen N(t) Sustainability Live, 2nd April 2014

8. Trend Matching Sustainability Live, 2nd April 2014

9. Focussed Intervention Nottinghamshire sources Nottinghamshire sources: % contribution to groundwater N loading Yellow = fertiliser applications to arable land White = areas relevant forchange in arable land use Sustainability Live, 2nd April 2014

10. Catchment Management Feasibility Sustainability Live, 2nd April 2014

11. Timing Unsaturated zone thickness (5 to 65 m) Groundwater flow path length(0 to 9500 m) Travel time (3 to 60 years) Sustainability Live, 2nd April 2014

12. Modelling Effect of Measures Fertiliser recommendation system, integrate manure N and clover in place of fertiliser Sustainability Live, 2nd April 2014

13. The Cost of Measures Based on FarmScoper tool, or in the ADAS-led report “Inventory of Mitigation Methods and Guide to their Effects on Diffuse Water Pollution’ Sustainability Live, 2nd April 2014

14. Acceptability of Measures Farmers are willing to work with STW on a commercial basis However....... • There is already widespread good practice in nutrient management • Fertiliser practice is in line with the recommendations of the Fertiliser Manual RB209 But..... • There are high risk crops and livestock within catchments • All farmers surveyed are willing to investigate sub-optimal fertiliser application • There is potential for the increased use of cover crops Therefore..... • Optimising fertiliser use may not be effective • Use of cover crops, sub-optimal fertiliser application and removal of leaky crops could be used to reduce losses • There would need to be some investment to achieve change in each of these Results of farmer surveys Sustainability Live, 2nd April 2014

15. Cost Benefit Assessment Methodology Looks at 4 factors: • Required target reduction in N loading • Reduction is calculated by comparing the target concentration with the counterfactual. This gives the required % reduction in concentration at the source and therefore load to the catchment • The counterfactual (maximum predicted long-term peak concentration under a do-nothing scenario) • Calculated as the sum of: long term average concentration (from trend-fitting model) plus 2SD of the sample-by- sample variability in concentration (from statistical review of data) • Reduction for each catchment management measure • Reduction in loading is multiplied by the affected area and the likely uptake to give a % reduction in loading to the catchment and therefore concentration at the abstraction • Comparison of catchment and treatment costs over one 60-year period Feasibility of catchment management vs. treatment Sustainability Live, 2nd April 2014

16. Treatment Cost and Cost Avoidance Counterfactual Cost avoidance/savings • Cost of installing new treatment in AMP6 • Cost of upgrading treatment • Cost of a new source • Deferral of new treatment into later AMPs • Complete avoidance of new treatment • Reduced treatment running costs • Protection of blends through improved asset management Sustainability Live, 2nd April 2014

17. Cost Benefit Example Results Comparison of catchment and treatment costs over one 60-year period Blue = peak concentration Orange = target concentration Red = counterfactual Grey = engineering solution Green = catchment management solution Sustainability Live, 2nd April 2014

18. Potential AMP6 Programme Investigated 37 groundwater sources in AMP5 8 groundwater catchments where we have opted for catchment management schemes • 4 catchments where we are aiming for no deterioration in water quality • 4 catchments where we need to reduce nitrate peaks On average a cost benefit analysis ratio of £1:£4.00 has been calculated Farmers are willing to work with STW on a commercial basis Opportunities to work in partnership and bring wider environmental benefits to catchments Severn Trent customers and stakeholders strongly support greater catchment management and partnership working to protect raw water sources and to avoid the need for expensive treatment Catchment management has a lower whole life cost compared to traditional treatment solutions Sustainability Live, 2nd April 2014

19. Thank you