Agricultural water management using two-stage channels : Performance and policy recommendations based on Northern European experiences
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A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
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Date
2021-08-02
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en
Pages
26
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Sustainability (Switzerland), Volume 13, issue 16
Abstract
Conventional dredging of ditches and streams to ensure agricultural drainage and flood mitigation can have severe environmental impacts. The aim of this paper is to investigate the potential benefits of an alternative, nature-based two-stage channel (TSC) design with floodplains excavated along the main channel. Through a literature survey, investigations at Finnish field sites and expert interviews, we assessed the performance, costs, and monetary environmental benefits of TSCs in comparison to conventional dredging, as well as the bottlenecks in their financing and governance. We found evidence supporting the expected longer-term functioning of drainage as well as larger plant and fish biodiversity in TSCs compared to conventional dredging. The TSC design likely improves water quality since the floodplains retain suspended sediment and phosphorus and remove nitrogen. In the investigated case, the additional value of phosphorus retention and conservation of protected species through the TSC design was 2.4 times higher than the total costs. We demonstrate how TSCs can be made eligible for the obligatory vegetated riparian buffer of the European Union agri-environmental subsidy scheme (CAP-AES) by optimising their spatial application with respect to other buffer measures, and recommend to publicly finance their additional costs compared to conventional dredging at priority sites. Further studies on biodiversity impacts and long-term performance of two-stage channels are required.Description
Funding Information: The shares of financing of the investigated TSCs are reported in Table S9. The differences in financing illustrate the absence of a systematic nationwide approach for financing TSCs. The farmers’ share of the costs was rather low in the six pilot studies, averaging less than 10%. Most financing has been arranged through individual, externally funded research and development projects. Currently, in Finland, a TSC project may obtain state financial support in the form of either a drainage subsidy from Agrifood Research and Development Fund (MAKERA) managed by the ELY Centers (Regional State Authority) or from CAP-AES’s non-productive investments as wetland investment and maintenance allowance. However, overlapping subsidies cannot be received for the same drainage area. Support can cover no more than 40% of the costs, but environmentally friendly (i.e., nature-based) solutions, and particularly expensive structures, may increase the support percentage. In recent years, MAKERA has granted approximately 2.5 million €/year of state support for about 50 dredging projects. Funding Information: Funding: This research was funded by the Joint Research Centre of European Commission (contract no. 939642), Academy of Finland (grant no. 330217), the Finnish Cultural Foundation (grant no. 00201229) and by the Valumavesi project. Publisher Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
Keywords
Agricultural water management, Biodiversity, CAP-AES, Drainage, Flood management, Phosphorus, Suspended sediment, Two-stage channels, Vegetation, Water quality
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Citation
Västilä, K, Väisänen, S, Koskiaho, J, Lehtoranta, V, Karttunen, K, Kuussaari, M, Järvelä, J & Koikkalainen, K 2021, ' Agricultural water management using two-stage channels : Performance and policy recommendations based on Northern European experiences ', Sustainability (Switzerland), vol. 13, no. 16, 9349 . https://doi.org/10.3390/su13169349