WP2 focuses on assessment of N and P water quality targets in the catchments, the flows of nutrients and losses to waters from all economic activities and sectors, and methodologies to determine the required reduction in N and P loads to achieve the water quality targets. In this WP, different types of models are enhanced, applied and compared across the transboundary river basins in order to harmonise approaches to reduce sector nutrient losses in catchments.

Description of work

This work package will establish the baseline N and P load reduction targets required to restore and maintain safe ecological status in each of the study catchments, and identify an associated suite of potential environmental metrics to monitor progress towards environmental and broader sustainability goals consistent with EU Farm to Fork and Green Deal policies. This will be achieved by the application of a range of nutrient accounting, emission loading, source-apportionment and pollution swapping models and existing EU tools, whose outputs will drive the testing of BMP scenarios in WP3 and the harmonisation of modelling approaches to achieving desired environmental outcomes in WP1.

Task 2.1 Collation and analysis of baseline catchment data. Lead: LU

This task will collate and compare the WFD water quality targets for N and P to reach good ecological status within the three study catchments. Water quality monitoring programmes operating in each catchment will be evaluated by each partner to identify trends in river N and P concentrations and loads from important point sources over the last 20 years as a result of land-based pressures and/or mitigation. Sector contributions to N and P loading in each catchment will be reviewed and current nutrient concentrations in the catchments will be compared against the WFD-targets. This inventory data will be used to inform baseline modelling projections and will directly feed into WP1 to assess scope for harmonisation of evidence-based water quality targets across the wastewater and agriculture sectors.

Task 2.2 Quantification of nutrient (NP) stocks and flows in each catchment. Lead: LU

In this task a detailed material flow analysis (MFA) of inputs, outputs and internal flows of N, P and C, and their interactions, will be undertaken within each catchment using best available input data for contributing economic activities and sectors. LU will apply the same MFA model to all catchments in cooperation with partners and stakeholders to ensure maximum possible harmonised evaluation of key sector drivers of N and P flows and losses, and potential for improving N and P efficiency, reducing surplus stores of N and P in the landscape and recirculating N and P to close nutrient cycles. The contribution of sector activities to climate change impacts will be assessed through inventory data on annual flows of C and N to air and soil. The impacts of structural system and sector change to meet zero GHG emission goals, or which may result from future climate change (from Task 3.2), on N, P and C flows and sector performance metrics will be evaluated.

Task 2.3 Development of enhanced N and P emission models to quantify baseline load projections. Lead: VMM

Selected models will be applied by the partners within each of the catchments to quantify baseline N and P emissions to water from the point and diffuse sources at sub-annual timesteps. These models will be further developed (by refining emission rates, sources and pathways for different land use activities using latest research) to ensure an enhanced capability to quantify the contribution of the relevant sectors to the total N and P loads to water and assess (by modelling) the impact of a range of BMPs. The MITERRA model will be used to quantify gaseous emissions of N and C flows to soil from the agriculture sector. The likely impacts of climate change will be explored by comparing model performance with water quality monitoring NP load data for very dry and very wet years, and under extreme events, and by assessing how sub-model routines behave under varying climatic conditions (precipitation, temperature). Improved predictions of N and P emissions to water, air and soil will be fed back into the MFA model (Task 2.2) for improved quantification of sector performance and associated sustainability metrics.

Task 2.4 Quantification of required load reduction targets. Lead: WR

The required load reduction in the catchments will be based on the exceedance of the WFD-targets for N and P concentrations. Exceedances will be translated into total required load reductions. Assumptions and applied methods to allocate these load reductions to the sectors that deposit the nutrients in the water system will be presented and discussed with the PSWG and additional regional stakeholders. Important assumptions are beforehand cost-efficiency of mitigation measures, upstream sources, sources that can be considered as natural or historical, the timeline to determine the load reductions and possible impact of climate change. As a result, a few selected methods will be applied and evaluated using the source flow models at catchment level. The load reduction targets for the sectors will drive the BMP scenario testing in WP3.

Task 2.5 Selection of environmental indicators and metrics. Lead: LU

A meta-analysis of model outputs (Task 2.2 and 2.3) will be undertaken by LU to identify a suite of pragmatic environmental indicators to monitor BMP impacts on system N and P efficiency and losses, and progress towards reaching the water quality targets within each catchment. This meta-analysis will examine the relationships between sector input variables (e.g. land use, livestock numbers, population), sector performance (NP efficiency, surplus, circularity) based on MFA outputs (Task 2.2), and catchment N and P losses based on N and P emission model outputs (Task 2.3). Together with catchment specific information on current legislation, water quality monitoring capability and Europe-wide emission accounting tools (e.g. EDGAR and FASSt), the outputs of the meta-analysis will be fed into WP1 for selection of harmonised environmental indicators and metrics in NW Europe.