CircuLar Economy Approach to River pollution by Agricultural Nutrients with use
of Carbon-storing Ecosystems



Project Interactive Website

 Wiktor Kotowski

Wiktor Kotowski

Executive Coordinator 

Projects  Partner and Institution:

University of Warsaw (UW)
Warsaw University of Life Sciences (SGGW)
Green Management Group (GMG)
University of Greifswald (UG)
Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB)
University of Aarhus (AU)
University of Nijmegen (UN)


Key words

wetland buffer zones (WBZ), agricultural nutrients, paludiculture, ecosystem services


Riverine wetlands provide a range of ecosystem services: cultural (esthetics, recreation and education), provisioning (storage and retention of water), supporting (soil formation and nutrient cycling), regulating (regulation of erosion, natural hazards, hydrological flows, climate, water purification and waste treatment). The project CLEARANCE focuses on the role of wetland buffer zones (WBZ) in agricultural catchments that clean water from excess nutrients before it reaches the river, as well as substantially contribute to the natural purification of river water. The project aims to demonstrate this role of WBZs using model catchments, while at the same time examining synergies between water purification and other ecosystem services. The key concept of CLEARANCE is to enhance multifunctional use of riverine wetlands via circular economy, where nutrients captured in wetland biomass are re-used to produce energy (via combustion, biogas or pyrolysis), materials or soil substrates (compost), while at the same time reducing greenhouse gas emissions via rewetting of drained organic soils and re-establishment of peat formation. Last but not least, riparian biodiversity and recreational functions of riverine wetlands are treated as co-benefits of the above-listed services, altogether allowing for a multi-faceted evaluation of WBZs and developing an integrated framework - socio-economic, environmental and political - for the implementation of WBZs in circular economy. CLEARANCE will deliver: (1) assessment of synergies and constraints between nutrient removal in WBZ and biomass utilization; (2) analysis of market and non-market values of rivers and river ecosystem services (as co-benefits of WBZ); (3) quantification and upscaling of costs and benefits of WBZ at the catchment scale; (4) policy and social network analysis concerning feasibility of using WBZ in circular economies as a solution to agricultural nutrients pollution; (5) market assessment of commodification options of WBZ-related ecosystem services, including nutrient removal and biomass production.

Project structure

CLEARANCE is structured into three phases: (A) background knowledge & methods justification, (B) modelling in case catchments, (C) outreach and dissemination.
In phase A data from the nationwide Danish monitoring program and Danish databases on land use, soil type, precipitation data, hydrological measurements and transport of nutrients in rivers will be used to set up empirical models, which can predict the loss of N from the upland to the stream. These models will be coupled with specially-adapted hydrological models, in order to produce a tool that allows to identify nutrient pathways and quantify their loads on different types of WBZ. Based on the established and regularly updated database for different paludiculture plants, we will develop a database for WBZ management options with yields, nutrient contents and biomass quality parameters for specific use options. Recycling possibilities in production systems in WBZ will be analyzed through available data from own and external sampling. Willingness to pay (WTP) for different attributes associated with different river valleys management options (restoring WBZ, restoring meanders, the scope of paludiculture etc.) will be assessed in PL, DE and DK. Discourse analysis from environmental ethics will be used to first provide a comprehensive account of “water valuation” and related intrinsic, instrumental and relational values in the case of wetland-buffer zone with paludiculture as a proposed socio-ecological innovation and putative contribution to healthy rivers. The analysis will also identify and value conflicts, including these caused by the monetization and commodification of ecosystem services.
In phase B, knowledge gathered and tools developed in phase A will be implemented in model catchments in Danmark, Germany and Poland. For each catchment, GIS-based models including climate, hydrology, land cover, river valley vegetation, hydrological data will be elaborated and N & P sources and pathways will be identified. Ecosystem services values in case catchments will be quantified for different kinds of WBZ development. Summing all the results up, we will quantify costs and benefits of WBZ for all case catchments, under different scenarios and in respect of market and non-market values.
Within phase C scientific publications and practical guidelines and recommendations will be prepared.


CLEARANCE consists of seven thematic workpackages (WP).
WP1 - Upland sources recharging WBZ is aimed to build a tool and framework for identification of spatially explicit nutrient input hotspots toward existing and projected WBZ.
WP2 - Wetlands as buffers is aimed to establish methods of quantifying nutrient capture in WBZ and apply them to case catchments. The calculated nitrogen and phosphorus load on the riparian areas will be used to estimate how maintenance, creation or restoration of the riparian WBZ impacts stream transport of nutrients.
WP3 - Closing the loop: biomass use, nutrient removal & commodification of nutrient recycling is aimed to analyze options of combining nutrient removal including nutrient recycling (ashes, substrates) potential and biomass utilization. WP3 compiles land management options that combine nutrient removal including nutrient recycling potential and biomass utilization.
WP4 - Water cycles and hydrological boundary conditions is aimed to localize and delimit WBZ, quantify available water in case catchments; assess hydrological co-benefits. WP4 is oriented at quantification of hydrological processes allowing WBZ to act as nutrient sources and sinks in the catchment scale.
WP5 - Co-benefits: evaluation of ecosystem services is aimed to estimate cultural services and pure non-use values related to different WBZ scenarios . In the context of cultural services our work will focus on estimating recreational, aesthetics values related to WBZ. Since WBZ are also likely to have a very large impact on biodiversity conservation we will also assess existence value related to biodiversity.
WP6 - Policy and civil society: barriers and opportunities is aimed to identify policy and social constrains and opportunities of implementing WBZ. Extended social grid analysis focused on societal dynamics around innovations for the common good, e.g. here the proposed creation of wetland buffer zones with paludiculture. Regional workshops will communicate preliminary results and serve as a critical feedback from regional stakeholders for final recommendations.
WP7 - Integration & upscaling is aimed to integrate information on different ecosystem services and benefits from WBZ and synthesize in form of costs and benefits analysis on the catchment scale.


CLEARANCE aims to deliver diversified outputs addressed to four different target groups:

  • Scientific community - papers submitted to open-access international journals (possible replacement of individual submissions with a collaborative scientific book) and a scientific session on multifunctional WBZ offered at an international conference, along with conference papers at other scientific symposia,
  •  Stakeholders connected to WBZ (water authorities, experts, farmers, anglers, etc.) - three national stakeholder workshops, practical guidelines on multifunctional WBZ in circular economy, brochure and video materials with examples of WBZ at work,
  • Decision makers at EU level - recommendation document on for innovation in Common Agricultural Policy and Water Framework Directive employing WBZ concept as parts of circular economies in agricultural catchments.

References coordinator and  leaders of  each WP

WP1 – Dominik Zak (IGB)
WP2 – Carlos C. Hoffmann (AU)
WP3 – Wendelin Wichtmann (UG)
WP4 – Mateusz Grygoruk (SGGW)
WP5 – Marek Giergiczny (UW)
WP6 – Rafael Ziegler (UG)
WP7 – Wiktor Kotowski (UW)

Contact Point for  Communication/Dissemination activities:

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Contact Point for Open Data/Open Access activities:

Marta Wisniewska

Photo of the Research Team: