Legacies of Agricultural Pollutants (LEAP):
Integrated Assessment of Biophysical and Socioeconomic Controls on Water Quality in Agroecosystems

Project Website

van cappellen 

Coordinator: Prof. Dr. Philippe Van Cappellen

Projects  Partner and Institution:
Jerker Jarsjö, Stockholm University
Søren Bøye Olsen, University of Copenhagen
Maria Cunha, University of Coimbra
Nandita Basu, University of Waterloo

Key words: agricultural pollutants, nutrient legacies, best management practices (BMPs), time-lags, watershed nutrient models, nitrogen, phosphorus.


Agricultural nitrogen (N) and phosphorus (P) fertilizer applications have greatly improved agricultural productivity. An unintended consequence of fertilizer use is the negative impact of nutrient enrichment on water quality and aquatic ecosystem health. Agricultural beneficial management practices (BMPs) have been implemented to combat this threat. However, the legacy stores of N and P accumulated in the landscape over decades of fertilizer application are slow to be released from the soil, hence, creating time lags between BMP implementation and measurable water quality improvements. The LEAP project addressed the scientific challenges of reconstructing the accumulation and predicting the ensuing fate of N and P legacies in contrasting agroecosystems in Canada and Europe, and then translating the newly acquired data and knowledge base into water quality risk and associated social and economic cost assessments. 

Nutrient input-output trajectories have been completed at the river basin scale in Canada (Grand River), Portugal (Mondego) and Sweden (Norrström) following a common protocol that enables the comparative analysis of the trajectories in terms of historical land use and agricultural practices. In addition to producing maps showing the past and present-day distributions of legacies, model calculations were performed to estimate the time scales of release of stored N and P legacies. The time lags of surface water quality recovery are typically on the order of decades. A predictive understanding of nutrient legacy source zones and transport pathways enables locating where BMPs would be most effective in reducing the release of agricultural nutrient legacies to the river network. For example, an erosional P export risk assessment was carried out for the entire province of Ontario to prioritize the implementation of soil conservation measures. 

To broadly assess public knowledge and perceptions about the impacts of agriculture on water quality, Q-methodology focus groups and surveys were conducted in all four countries, complemented with personal interviews and an initial online questionnaire pilot test. Based on the preliminary findings, a final questionnaire was developed and used to collect online data from over 3000 respondents in all four countries. The surveys show a remarkable convergence of people’s appreciation of the benefits of water quality improvements across the different geographies, cultures and agricultural systems. Work has also focused on integrating nutrient legacy time lags, social welfare benefits of water quality improvements and cost-effectiveness analyses, in order to guide policies and BMPs aimed at reducing the negative consequences of N and P enrichment on water quality while minimizing trade-offs.

The LEAP project has yielded innovative model developments, assessment strategies and protocols that address the role of agricultural N and P legacies in water quality from a holistic, socio-ecological perspective. The comparative analyses among the four countries underscore the general applicability of these tools across variable agricultural management systems, climate conditions and affected water bodies, as well as different regulatory and social contexts. The results of the project are being broadly disseminated to end-users including regulatory authorities and agencies, and farmer and environmental organizations in Europe and Canada. The project’s research products, including a webinar series summarizing the analytical capabilities and major findings of LEAP, can be found on the website:

Project structure:
LEAP is comprised of five interlinked Work Packages (WPs), each lead by a researcher from one of the partner institutions.
WP 1 will form the practical and analytical framework of LEAP. WP 2 will focus on biophysical modelling of N and P at the selected exemplar sites. WP 3 will link economics and agricultural practices in a hydro-economic framework. WP 4 will develop a framework to support policy and decision-making. WP 5 will integrate the results of WP 2 – 4 into an agroecosystem typology.

The organizational structure includes: the management committee (includes WP leads and consortium coordinator), the project office, and an external advisory committee.

project structure1

LEAP research will be focused on five exemplar sites: Boreal Shield Forest, Canada; Grand River Watershed, Canada; Norrström Catchment, Sweden; Limfjorden and Odense Catchments, Denmark; and Mondego River Basin, Portugal. Each WP has established tasks, deliverables (D), and milestones to ensure that project objectives are met. Methods and research areas for each WP are displayed in the accompanying figure.


Work Package 1: Framing, Coordination and Dissemination
D1.1: Working paper on analytical framework for LEAP
D1.2: International youth forum on agriculture and water
D1.3: Knowledge mobilization event – session at international conference
D1.4: Mid-term and final reports
Work Package 2: Biophysical Analysis of Nutrient Legacies
D2.1 Working papers (2) comparing nutrient input/output trajectories from the exemplars
D2.2 Maps showing N and P legacies for the exemplar sites
D2.3 Delivery of nutrient model results to WP3 and WP4
D2.4 Working papers (2) on watershed nutrient model incorporating legacies
Work Package 3: Hydro-economics of Agricultural Pollutant Legacies
D3.1 Working papers detailing the cost-effectiveness analysis in the exemplars
D3.2. Working paper with results from choice experiment
D3.3. Working papers (2) on hydro-economic decision-support and CBA
D3.4. Delivery of CEA and CBA results to WP4 – iterative process
Work Package 4: Uncertainties and Risk Management
D4.1. Working papers (2) on the general framework and integrating uncertainty in exemplars
D4.2 Uncertainty results delivered to Task 5.4
Work Package 5: Upscaling and Adaptation Portfolios
D5.1 Nutrient legacy system typology for exemplars & national/regional scales
D5.2 Working papers (4) on LEAP typology, scaling up and portfolios
D5.3 Policy briefs targeted to EU and national groups based on Task 5.4
D5.4 Roadmap that identifies most cost-effective nutrient reduction strategies.

References coordinator and  leaders of  each WP:
• WP 1 leader: Philippe Van Cappellen
• WP 2 leader: Jerker Jarsjö
• WP 3 leader: Søren Bøye Olsen
• WP 4 leader: Maria Cunha
• WP 5 leader: Nandita Basu

Main outputs

  • Vero, S. E., Basu, N. B., Meter, K. V., Richards, K. G., Mellander, P.-E., Healy, M. G., & Fenton, O. (2017). Review: the environmental status and implications of the nitrate time lag in Europe and North America. Hydrogeology Journal, 26, 722.
  • Van Meter, K. J., & Basu, N. B. (2017). Time lags in watershedscale nutrient transport: an exploration of dominant controls. Environmental Research Letters, 12(8), 084017.
  • Dawson, L., Persson, K., Balfors, B., Mörtberg, U. and Jarsjö, J. (2018). Impacts of the water framework directive on learning and knowledge practices in a Swedish catchment. Journal of Environmental Management, 223, 731-742.
  • Destouni, G. and Jarsjö, J. (2018). Zones of untreatable water pollution call for better appreciation of mitigation limits and opportunities. Wiley Interdisciplinary Reviews: Water, e1312.

More results on the project: Data and resources

Contact Point for  Communication/Dissemination activities: Tatjana Milojevic (

Contact Point for Open Data/Open Access activities:Tatjana Milojevic (

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published on 2017/03/23 10:00:00 GMT+1 last modified 2022-05-10T14:50:40+01:00