Possible approach for riverine nutrient loads data EMODnet Chemistry 3 1st TWG meeting, 4-5 April 2017 Possible approach for riverine nutrient loads data ISPRA+ICES EMODnet Chemistry 3 TWG meeting, 4-5 April 2017 1

EU Reporting Riverine nutrients loads are requested by: In River Basin Management Plans from WFD, nitrogen and phosphorous loads are usually assessed at river basin levels, for ex. N tons/year discharged in the river basin from point (UWWTPs) and diffuse sources (agriculture). But this is not the riverine input at river mouth discharged into sea, a retention coefficient needs to be applied in order to calculate the riverine input. Anyway, some River Basin Management Authorities (for ex. in Italy the Po RBMA), provide an estimate of N and P riverine input at river mouth. 2012 MSFD Reporting on art. 8 of MSFD, required N, P and Organic Matter load from land based sources which include rivers but also coastal run-off. The new reporting due by 2018 does not explicitly request such information EMODnet Chemistry 3 TWG meeting, 4-5 April 2017 2

Other possible approach From the Inventory of Priority Substances of EQSD: For the list of priority substances, an inventory of discharges at river basin level has to be produced by River Basin Management Authorities with an estimate of total annual amount discharged in the river basin for each relevant priority substance. There are three possible approach: Source based approach Life Cycle approach Riverine input approach For riverine input approach, mean annual river flow at river mouth has to be estimated (by direct measurements or hydrological modelling or both). Then multiplying the mean annual concentration of priority substance with mean annual river flow (both at river mouth), an estimate of riverine input load can be deduced. Using the mean annual concentration of nutrients at river mouth, also nutrient riverine input load could be estimated. EMODnet Chemistry 3 TWG meeting, 4-5 April 2017 3

Summary Possible approach for riverine nutrient loads data: From 2015 RBMP: an estimate of N and P riverine input at river mouth. Only some River Basin Authorities provide such information. From 2018 MSFD Reporting on MFSD: N, P and Organic Matter load from land based sources which include rivers. Verify if new reporting explicitly requires such information and separate river contribution from run-off From 2015 Priority Substance inventory: use mean annual river flow at river mouth x mean annual nutrients concentration. Many RBA have adopted riverine input approach and estimate of mean annual river flow are generally available for main rivers. EMODnet Chemistry 3 TWG meeting, 4-5 April 2017 4