Mitigating nutrient leaching from green roofs with biochar

Research output: Contribution to journalArticleScientificpeer-review

Abstract

Green roofs may have great potential for managing urban runoff but their effects on the quality of infiltrating water are highly variable. At worst, it can contain high concentrations of nutrient pollutants, especially phosphorus. We made a survey in southern Finland and found much higher concentrations of phosphorus and nitrogen in runoff from existing green roofs than nearby non-vegetated bituminous and tin roofs. However, metal concentrations in runoff generally exhibited an opposite pattern. Media mixtures with aggregates, such as biochar, have been suggested as a means of retaining nutrients in green roof substrate. Thus, we set up a green roof platform experiment in order to study the amendment of biochar in a substrate consisting of mainly recycled crushed brick, by using two vegetation establishment methods: pre-grown mats and planting with seeds and plug plants. We monitored the effect of biochar on runoff during one year across all four seasons, including winter with periods of freezing and thawing. At the beginning of the experiment we found negligible impacts of biochar, but when the systems had matured for less than one year, biochar retained nutrients. The total annual loads of both nutrients were significantly reduced by biochar amendment in both green roof types. Efficient solutions are needed if urban greening, such as green roofs, is to be applied in a way that does not produce ecosystem disservices like nutrient pollution. According to our results, amending green roof substrates with biochar could be a partial solution to the nutrient pollution problem. (C) 2016 Elsevier B.V. All rights reserved.
Original languageEnglish
JournalLandscape and Urban Planning
Volume152
Pages (from-to)39-48
Number of pages10
ISSN0169-2046
DOIs
Publication statusPublished - Aug 2016
MoE publication typeA1 Journal article-refereed

Fields of Science

  • RUNOFF WATER QUANTITY
  • RAINWATER RUNOFF
  • QUALITY PERFORMANCE
  • SUBSTRATE DEPTH
  • URBAN AREAS
  • POLLUTION
  • ABATEMENT
  • DYNAMICS
  • SERVICES
  • FINLAND
  • 1181 Ecology, evolutionary biology
  • 1172 Environmental sciences

Cite this

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title = "Mitigating nutrient leaching from green roofs with biochar",
abstract = "Green roofs may have great potential for managing urban runoff but their effects on the quality of infiltrating water are highly variable. At worst, it can contain high concentrations of nutrient pollutants, especially phosphorus. We made a survey in southern Finland and found much higher concentrations of phosphorus and nitrogen in runoff from existing green roofs than nearby non-vegetated bituminous and tin roofs. However, metal concentrations in runoff generally exhibited an opposite pattern. Media mixtures with aggregates, such as biochar, have been suggested as a means of retaining nutrients in green roof substrate. Thus, we set up a green roof platform experiment in order to study the amendment of biochar in a substrate consisting of mainly recycled crushed brick, by using two vegetation establishment methods: pre-grown mats and planting with seeds and plug plants. We monitored the effect of biochar on runoff during one year across all four seasons, including winter with periods of freezing and thawing. At the beginning of the experiment we found negligible impacts of biochar, but when the systems had matured for less than one year, biochar retained nutrients. The total annual loads of both nutrients were significantly reduced by biochar amendment in both green roof types. Efficient solutions are needed if urban greening, such as green roofs, is to be applied in a way that does not produce ecosystem disservices like nutrient pollution. According to our results, amending green roof substrates with biochar could be a partial solution to the nutrient pollution problem. (C) 2016 Elsevier B.V. All rights reserved.",
keywords = "RUNOFF WATER QUANTITY, RAINWATER RUNOFF, QUALITY PERFORMANCE, SUBSTRATE DEPTH, URBAN AREAS, POLLUTION, ABATEMENT, DYNAMICS, SERVICES, FINLAND, 1181 Ecology, evolutionary biology, 1172 Environmental sciences",
author = "Kuoppam{\"a}ki, {Kirsi Helena} and Lehv{\"a}virta, {Ritva Susanna}",
year = "2016",
month = "8",
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Mitigating nutrient leaching from green roofs with biochar. / Kuoppamäki, Kirsi Helena; Lehvävirta, Ritva Susanna.

In: Landscape and Urban Planning, Vol. 152, 08.2016, p. 39-48.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Mitigating nutrient leaching from green roofs with biochar

AU - Kuoppamäki, Kirsi Helena

AU - Lehvävirta, Ritva Susanna

PY - 2016/8

Y1 - 2016/8

N2 - Green roofs may have great potential for managing urban runoff but their effects on the quality of infiltrating water are highly variable. At worst, it can contain high concentrations of nutrient pollutants, especially phosphorus. We made a survey in southern Finland and found much higher concentrations of phosphorus and nitrogen in runoff from existing green roofs than nearby non-vegetated bituminous and tin roofs. However, metal concentrations in runoff generally exhibited an opposite pattern. Media mixtures with aggregates, such as biochar, have been suggested as a means of retaining nutrients in green roof substrate. Thus, we set up a green roof platform experiment in order to study the amendment of biochar in a substrate consisting of mainly recycled crushed brick, by using two vegetation establishment methods: pre-grown mats and planting with seeds and plug plants. We monitored the effect of biochar on runoff during one year across all four seasons, including winter with periods of freezing and thawing. At the beginning of the experiment we found negligible impacts of biochar, but when the systems had matured for less than one year, biochar retained nutrients. The total annual loads of both nutrients were significantly reduced by biochar amendment in both green roof types. Efficient solutions are needed if urban greening, such as green roofs, is to be applied in a way that does not produce ecosystem disservices like nutrient pollution. According to our results, amending green roof substrates with biochar could be a partial solution to the nutrient pollution problem. (C) 2016 Elsevier B.V. All rights reserved.

AB - Green roofs may have great potential for managing urban runoff but their effects on the quality of infiltrating water are highly variable. At worst, it can contain high concentrations of nutrient pollutants, especially phosphorus. We made a survey in southern Finland and found much higher concentrations of phosphorus and nitrogen in runoff from existing green roofs than nearby non-vegetated bituminous and tin roofs. However, metal concentrations in runoff generally exhibited an opposite pattern. Media mixtures with aggregates, such as biochar, have been suggested as a means of retaining nutrients in green roof substrate. Thus, we set up a green roof platform experiment in order to study the amendment of biochar in a substrate consisting of mainly recycled crushed brick, by using two vegetation establishment methods: pre-grown mats and planting with seeds and plug plants. We monitored the effect of biochar on runoff during one year across all four seasons, including winter with periods of freezing and thawing. At the beginning of the experiment we found negligible impacts of biochar, but when the systems had matured for less than one year, biochar retained nutrients. The total annual loads of both nutrients were significantly reduced by biochar amendment in both green roof types. Efficient solutions are needed if urban greening, such as green roofs, is to be applied in a way that does not produce ecosystem disservices like nutrient pollution. According to our results, amending green roof substrates with biochar could be a partial solution to the nutrient pollution problem. (C) 2016 Elsevier B.V. All rights reserved.

KW - RUNOFF WATER QUANTITY

KW - RAINWATER RUNOFF

KW - QUALITY PERFORMANCE

KW - SUBSTRATE DEPTH

KW - URBAN AREAS

KW - POLLUTION

KW - ABATEMENT

KW - DYNAMICS

KW - SERVICES

KW - FINLAND

KW - 1181 Ecology, evolutionary biology

KW - 1172 Environmental sciences

U2 - 10.1016/j.landurbplan.2016.04.006

DO - 10.1016/j.landurbplan.2016.04.006

M3 - Article

VL - 152

SP - 39

EP - 48

JO - Landscape and Urban Planning

JF - Landscape and Urban Planning

SN - 0169-2046

ER -