Articles
Does hedge plant choice play a role in rainfall-runoff reduction?
Article number
1429_15
Pages
131 – 138
Language
English
Abstract
Localised flooding events are becoming increasingly common in cities, due to more intense rainfall and the prevalence of impermeable surfaces which disrupt water flow.
Hedgerows are a common feature in gardens, parks and roadsides.
To date, there are few investigations into hedges’ rainfall run-off delay at the taxon level.
This study aims to characterise the impact plant choice has on the soil’s capacity for rainfall storage and the potential for the reduction of rainfall runoff, investigating how deciduous and evergreen species compare.
Here we present the results of summer measurements, as part of a year-long outdoor experiment with five evergreen (two broad-leaf and three conifers), and two deciduous cultivars grown in 15-L pots.
We assess the plant water use and soil moisture content (SMC) of ten 3- to 4-year-old individuals per taxon.
Weather data have also been gathered during experiments to assess the impact on SMC reduction.
SMC is being used as a proxy for the capacity of soil to store rainfall.
We assume that a greater reduction in SMC over time is linked to greater runoff reduction.
We found all but one taxon was effective at reducing SMC compared with bare soil, with clear inter- and infraspecific differences in reducing SMC overall.
The greatest overall reduction in SMC was by Elaeagnus × submacrophylla ‘Gilt Edge’. However, the two evergreen cultivars of E. × submacrophylla, and two Thuja plicata cultivars were particularly effective at reducing SMC during the four-day experiments.
Of the three T. plicata taxa tested ‘GOLDY’ (‘4ever’) was more effective than the others in reducing SMC and ‘Whipcord’ performed similarly to bare soil, demonstrating the differences at the cultivar level.
This study highlights the impact taxon selection has on reducing water run-off and therefore flood mitigation potential.
This research is continuing to assess the roles that seasonality (in terms of plants’ functional change), and plant management have in flood mitigation potential.
Hedgerows are a common feature in gardens, parks and roadsides.
To date, there are few investigations into hedges’ rainfall run-off delay at the taxon level.
This study aims to characterise the impact plant choice has on the soil’s capacity for rainfall storage and the potential for the reduction of rainfall runoff, investigating how deciduous and evergreen species compare.
Here we present the results of summer measurements, as part of a year-long outdoor experiment with five evergreen (two broad-leaf and three conifers), and two deciduous cultivars grown in 15-L pots.
We assess the plant water use and soil moisture content (SMC) of ten 3- to 4-year-old individuals per taxon.
Weather data have also been gathered during experiments to assess the impact on SMC reduction.
SMC is being used as a proxy for the capacity of soil to store rainfall.
We assume that a greater reduction in SMC over time is linked to greater runoff reduction.
We found all but one taxon was effective at reducing SMC compared with bare soil, with clear inter- and infraspecific differences in reducing SMC overall.
The greatest overall reduction in SMC was by Elaeagnus × submacrophylla ‘Gilt Edge’. However, the two evergreen cultivars of E. × submacrophylla, and two Thuja plicata cultivars were particularly effective at reducing SMC during the four-day experiments.
Of the three T. plicata taxa tested ‘GOLDY’ (‘4ever’) was more effective than the others in reducing SMC and ‘Whipcord’ performed similarly to bare soil, demonstrating the differences at the cultivar level.
This study highlights the impact taxon selection has on reducing water run-off and therefore flood mitigation potential.
This research is continuing to assess the roles that seasonality (in terms of plants’ functional change), and plant management have in flood mitigation potential.
Authors
J. Bilsborrow, J. Barker, M.D. Christodoulou, T. Blanua
Keywords
gardens, hedgerows, ecosystem services, rainfall mitigation, urban flooding
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