Biochar amendment in the green roof substrate affects runoff quality and quantity

Research output: Contribution to journalArticleScientificpeer-review

Abstract

The utilisation of ecosystem services has been suggested as one solution to manage urban environmental problems, one of which is the excessive quantity or poor quality stormwater. As roofs contribute significantly to the amount of runoff, vegetated, i.e. green roofs have become an increasingly popular way to manage urban water in densely built areas. However, green roofs may introduce a new source of water pollution evidenced as higher concentrations of nutrients, especially phosphorus, in runoff compared to that in precipitation inputs. In two controlled, replicated experiments, one in the field for 7 months and another in the laboratory for 6 weeks, the amendment of biochar to green roof substrates was studied for its potential to mitigate the leaching of nutrients from newly installed pre-grown green roof Sedum and meadow mats. Nutrient concentrations were an order of magnitude higher in runoff from green roofs than in rain water. In the field experiment, biochar reduced the cumulative leaching of nutrients, even though biochar did not significantly reduce nutrient concentrations. These results can be interpreted as a combined impact of biochar on both the quantity and quality of runoff over time, the quantitative effect being apparently stronger than the qualitative. In the laboratory experiment, one type of biochar reduced nutrient concentrations and load in runoff while another type had an opposite effect. As the properties of biochar can vary considerably, careful studies are necessary before large-scale implementation of biochar amendment in green roofs are considered, to avoid unintended consequences.
Original languageEnglish
JournalEcological Engineering
Volume2016
Issue number88
Pages (from-to)1-9
Number of pages9
ISSN0925-8574
DOIs
Publication statusPublished - 2016
MoE publication typeA1 Journal article-refereed

Fields of Science

  • 1183 Plant biology, microbiology, virology
  • Living roof
  • Stormwater
  • Water quality
  • Nutrients
  • Charcoal
  • Water pollution
  • Soil amendment

Cite this

@article{db41821f1fb141a4946eda99390186b9,
title = "Biochar amendment in the green roof substrate affects runoff quality and quantity",
abstract = "The utilisation of ecosystem services has been suggested as one solution to manage urban environmental problems, one of which is the excessive quantity or poor quality stormwater. As roofs contribute significantly to the amount of runoff, vegetated, i.e. green roofs have become an increasingly popular way to manage urban water in densely built areas. However, green roofs may introduce a new source of water pollution evidenced as higher concentrations of nutrients, especially phosphorus, in runoff compared to that in precipitation inputs. In two controlled, replicated experiments, one in the field for 7 months and another in the laboratory for 6 weeks, the amendment of biochar to green roof substrates was studied for its potential to mitigate the leaching of nutrients from newly installed pre-grown green roof Sedum and meadow mats. Nutrient concentrations were an order of magnitude higher in runoff from green roofs than in rain water. In the field experiment, biochar reduced the cumulative leaching of nutrients, even though biochar did not significantly reduce nutrient concentrations. These results can be interpreted as a combined impact of biochar on both the quantity and quality of runoff over time, the quantitative effect being apparently stronger than the qualitative. In the laboratory experiment, one type of biochar reduced nutrient concentrations and load in runoff while another type had an opposite effect. As the properties of biochar can vary considerably, careful studies are necessary before large-scale implementation of biochar amendment in green roofs are considered, to avoid unintended consequences.",
keywords = "1183 Plant biology, microbiology, virology, Living roof, Stormwater, Water quality, Nutrients, Charcoal, Water pollution, Soil amendment",
author = "Kuoppam{\"a}ki, {Kirsi Helena} and Marleena Hagner and Lehv{\"a}virta, {Ritva Susanna} and Set{\"a}l{\"a}, {Heikki Martti}",
year = "2016",
doi = "10.1016/j.ecoleng.2015.12.010",
language = "English",
volume = "2016",
pages = "1--9",
journal = "Ecological Engineering",
issn = "0925-8574",
publisher = "Elsevier Scientific Publ. Co",
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TY - JOUR

T1 - Biochar amendment in the green roof substrate affects runoff quality and quantity

AU - Kuoppamäki, Kirsi Helena

AU - Hagner, Marleena

AU - Lehvävirta, Ritva Susanna

AU - Setälä, Heikki Martti

PY - 2016

Y1 - 2016

N2 - The utilisation of ecosystem services has been suggested as one solution to manage urban environmental problems, one of which is the excessive quantity or poor quality stormwater. As roofs contribute significantly to the amount of runoff, vegetated, i.e. green roofs have become an increasingly popular way to manage urban water in densely built areas. However, green roofs may introduce a new source of water pollution evidenced as higher concentrations of nutrients, especially phosphorus, in runoff compared to that in precipitation inputs. In two controlled, replicated experiments, one in the field for 7 months and another in the laboratory for 6 weeks, the amendment of biochar to green roof substrates was studied for its potential to mitigate the leaching of nutrients from newly installed pre-grown green roof Sedum and meadow mats. Nutrient concentrations were an order of magnitude higher in runoff from green roofs than in rain water. In the field experiment, biochar reduced the cumulative leaching of nutrients, even though biochar did not significantly reduce nutrient concentrations. These results can be interpreted as a combined impact of biochar on both the quantity and quality of runoff over time, the quantitative effect being apparently stronger than the qualitative. In the laboratory experiment, one type of biochar reduced nutrient concentrations and load in runoff while another type had an opposite effect. As the properties of biochar can vary considerably, careful studies are necessary before large-scale implementation of biochar amendment in green roofs are considered, to avoid unintended consequences.

AB - The utilisation of ecosystem services has been suggested as one solution to manage urban environmental problems, one of which is the excessive quantity or poor quality stormwater. As roofs contribute significantly to the amount of runoff, vegetated, i.e. green roofs have become an increasingly popular way to manage urban water in densely built areas. However, green roofs may introduce a new source of water pollution evidenced as higher concentrations of nutrients, especially phosphorus, in runoff compared to that in precipitation inputs. In two controlled, replicated experiments, one in the field for 7 months and another in the laboratory for 6 weeks, the amendment of biochar to green roof substrates was studied for its potential to mitigate the leaching of nutrients from newly installed pre-grown green roof Sedum and meadow mats. Nutrient concentrations were an order of magnitude higher in runoff from green roofs than in rain water. In the field experiment, biochar reduced the cumulative leaching of nutrients, even though biochar did not significantly reduce nutrient concentrations. These results can be interpreted as a combined impact of biochar on both the quantity and quality of runoff over time, the quantitative effect being apparently stronger than the qualitative. In the laboratory experiment, one type of biochar reduced nutrient concentrations and load in runoff while another type had an opposite effect. As the properties of biochar can vary considerably, careful studies are necessary before large-scale implementation of biochar amendment in green roofs are considered, to avoid unintended consequences.

KW - 1183 Plant biology, microbiology, virology

KW - Living roof

KW - Stormwater

KW - Water quality

KW - Nutrients

KW - Charcoal

KW - Water pollution

KW - Soil amendment

U2 - 10.1016/j.ecoleng.2015.12.010

DO - 10.1016/j.ecoleng.2015.12.010

M3 - Article

VL - 2016

SP - 1

EP - 9

JO - Ecological Engineering

JF - Ecological Engineering

SN - 0925-8574

IS - 88

ER -