Soil Water Assessment Tool (SWAT) simulated hydrological impacts of land use change from temperate grassland to energy crops: a case study in western UK

Amanda J Holder* (Corresponding Author), Rebecca Rowe, Niall P. McNamara, Iain S. Donnison, Jon McCalmont

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)
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When considering the large-scale deployment of bioenergy crops, it is important to understand the implication for ecosystem hydrological processes and the influences of crop type and location. Based on the potential for future land use change (LUC), the 10,280 km2 West Wales Water Framework Directive River Basin District (UK) was selected as a typical grassland dominated district, and the Soil & Water Assessment Tool (SWAT) hydrology model with a geographic information systems interface was used to investigate implications for different bioenergy deployment scenarios. The study area was delineated into 855 sub-basins and 7,108 hydrological response units based on rivers, soil type, land use, and slope. Changes in hydrological components for two bioenergy crops (Miscanthus and short rotation coppice, SRC) planted on 50% (2,192 km2) or 25% (1,096 km2) of existing improved pasture are quantified. Across the study area as a whole, only surface run-off with SRC planted at the 50% level was significantly impacted, where it was reduced by up to 23% (during April). However, results varied spatially and a comparison of annual means for each sub-basin and scenario revealed surface run-off was significantly decreased and baseflow significantly increased (by a maximum of 40%) with both Miscanthus and SRC. Evapotranspiration was significantly increased with SRC (at both planting levels) and water yield was significantly reduced with SRC (at the 50% level) by up to 5%. Effects on streamflow were limited, varying between −5% and +5% change (compared to baseline) in the majority of sub-basins. The results suggest that for mesic temperate grasslands, adverse effects from the drying of soil and alterations to streamflow may not arise, and with surface run-off reduced and baseflow increased, there could, depending on crop location, be potential benefits for flood and erosion mitigation.
Original languageEnglish
Pages (from-to)1298-1317
Number of pages20
JournalGlobal Change Biology. Bioenergy
Issue number11
Early online date26 Jul 2019
Publication statusPublished - Nov 2019

Bibliographical note

We are grateful for funding supplied by the Institute of Biology, Environment and Rural Sciences (IBERS), Aberystwyth University (IBERS receives strategic funding from BBSRC). Both IBERS and CEH were supported by MAGLUE (, an EPSRC-funded project (EP/M013200/1). The field site used for some of the Miscanthus crop measurements was originally developed and instrumented as part of the Carbo-biocrop (NE/H01067X/1) and Energy Technologies Institute-funded ELUM ( projects.


  • bioenergy
  • evapotranspiration
  • flooding
  • hidrology
  • MIscanthus
  • short rotation coppice
  • Streamflow


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