Retention of snowmelt and rain from extensive green roofs during snowcovered periods

publishedVersio

Concentrations and Retention Efficiency of Tire Wear Particles from Road Runoff in Bioretention Cells

Bioretention cells are popular stormwater management systems for controlling peak runoff and improving runoff water quality. A case study on a functional large-scale bioretention cell and a laboratory column experiment was conducted to evaluate the concentrations and retention efficiency of bioretention cells towards tire wear particles (TWP). The presence of TWP was observed in all soil fractions (500 µm) of the functional bioretention cell. TWP concentrations were higher (30.9 ± 4.1 mg/g) close to the inlet to the bioretention cell than 5 m away (19.8 ± 2.4 mg/g), demonstrating the influence of the bioretention cell design. The column experiment showed a high retention efficiency of TWP (99.6 ± 0.5%) in engineered soil consisting of sand, silty-sand, and garden waste compost. This study confirmed that bioretention cells built with engineered soil effectively retained TWP > 25 µm in size, demonstrating their potential as control measures along roads.publishedVersio

Intensifying rehabilitation of combined sewer systems using trenchless technology in combination with low impact development and green infrastructure

Throughout Europe, there is a considerable need for investment in the upgrade of sewer systems – due to three main factors: ageing infrastructure, climate change and urban population growth. The need for investments is expected to grow significantly in the years ahead. Trenchless rehabilitation (no-dig) of sewer pipelines is a cost-efficient and environmental friendly method for upgrading existing pipelines with sufficient capacity. This study examines the possibility of applying no-dig to combined sewer systems (CS) with insufficient capacity. In this study, a concept assessment methodology that combines the analytical approaches from stormwater and sewer system assessments is presented. The methodology was tested on a case area that was part of an environmental project in Oslo, Norway. Three alternative concepts were examined; A0: no-dig and low impact development (LID), A1: no-dig, LID and green infrastructure (GI), and A2: CS up-sizing using open-cut methods. The study concludes that CS with insufficient capacity can be rehabilitated using no-dig if LID and GI. The combination of no-dig and LID reduces costs considerably but does involve the risk of damages from uncontrolled surface runoff. The main risk-reduction measure is the development of GI as an integrated stormwater management system that requires cross-sector collaboration within municipalities.publishedVersio

Grønne forsøkstak i Norges landskapslaboratorium, NMBU: Rapport for perioden 2018 – 2022

Denne rapporten gir en kortfattet oversikt over forsøksanlegget for grønne tak i Planteskolen ved Norges landskapslaboratorium, NMBU, og oppsummerer driftserfaringer og måleresultater for perioden 2018 – 2022. Anlegget ble etablert våren 2018 for å studere takenes funksjon som overvannstiltak, og måleresultater er samlet inn siden sommer/høst 2018. Anlegget består av tre 50 m2 store forsøkstak hvorav ett tak er et ordinært tekket referansetak og to tak er identiske grønne tak med et 150 mm tykt magasinerende sjikt med finknust LECA (0 – 6 mm) under en 40 mm tykk sedummatte. Takene er meget godt instrumentert for måling av hydrologisk relevante variabler, og innsamlede data er tilgjengelig gjennom NVEs portal Sildre. Foruten enkelte mindre driftsutfordringer, har forsøksanlegget fungert svært godt i perioden, men sedumvegetasjonen på de grønne takene er per i dag delvis fortrengt av mose. Det er uklart hvilken virkning dette har hatt på takenes hydrologi. Regelmessig skjøtsel ville trolig kunne forebygget moseveksten. Nedbørmålingene ved takene viser god overensstemmelse på månedsbasis med andre målestasjoner i Ås, med noen avvik, særlig om vinteren. I en noe forenklet analyse er det funnet 13 nedbørhendelser med anslått gjentaksintervall større enn 2 år. Innsamlede data viser at omtrent 27 % av totalnedbøren ble holdt tilbake i de grønne takene i måleperioden. Dette er så vidt noe høyere enn ved forsøkstak i Oslo som ikke har det magasinerende LECA-laget. Videre har gjennomgangen vist at spissavrenningen ved større enkelthendelser reduseres med mer enn 95 % i de grønne takene sammenliknet med referansetaket. Forsøksanlegget har vært en svært verdifull kilde til masteroppgaver, og det er per sommeren 2023 gjennomført åtte masteroppgaver (10 studenter) knyttet til takene, med varierte problemstillinger. For perioden 2023 – 2027 er det aktuelt å bygge om det ene grønne taket til et anlegg med styrt sluk, mens det andre grønne taket beholdes som en referanse og for å danne lange tidsserier med samme takstruktur. Det er også et potensiale for å gjøre mer forskning med allerede innsamlede data, inkludert grundigere modelleringsarbeid.Grønne forsøkstak i Norges landskapslaboratorium, NMBU: Rapport for perioden 2018 – 2022publishedVersio

Concentrations and Retention Efficiency of Tire Wear Particles from Road Runoff in Bioretention Cells

Bioretention cells are popular stormwater management systems for controlling peak runoff and improving runoff water quality. A case study on a functional large-scale bioretention cell and a laboratory column experiment was conducted to evaluate the concentrations and retention efficiency of bioretention cells towards tire wear particles (TWP). The presence of TWP was observed in all soil fractions (500 µm) of the functional bioretention cell. TWP concentrations were higher (30.9 ± 4.1 mg/g) close to the inlet to the bioretention cell than 5 m away (19.8 ± 2.4 mg/g), demonstrating the influence of the bioretention cell design. The column experiment showed a high retention efficiency of TWP (99.6 ± 0.5%) in engineered soil consisting of sand, silty-sand, and garden waste compost. This study confirmed that bioretention cells built with engineered soil effectively retained TWP > 25 µm in size, demonstrating their potential as control measures along roads

Concentrations and Retention Efficiency of Tire Wear Particles from Road Runoff in Bioretention Cells

Bioretention cells are popular stormwater management systems for controlling peak runoff and improving runoff water quality. A case study on a functional large-scale bioretention cell and a laboratory column experiment was conducted to evaluate the concentrations and retention efficiency of bioretention cells towards tire wear particles (TWP). The presence of TWP was observed in all soil fractions (500 µm) of the functional bioretention cell. TWP concentrations were higher (30.9 ± 4.1 mg/g) close to the inlet to the bioretention cell than 5 m away (19.8 ± 2.4 mg/g), demonstrating the influence of the bioretention cell design. The column experiment showed a high retention efficiency of TWP (99.6 ± 0.5%) in engineered soil consisting of sand, silty-sand, and garden waste compost. This study confirmed that bioretention cells built with engineered soil effectively retained TWP > 25 µm in size, demonstrating their potential as control measures along roads

Intensifying rehabilitation of combined sewer systems using trenchless technology in combination with low impact development and green infrastructure

Throughout Europe, there is a considerable need for investment in the upgrade of sewer systems – due to three main factors: ageing infrastructure, climate change and urban population growth. The need for investments is expected to grow significantly in the years ahead. Trenchless rehabilitation (no-dig) of sewer pipelines is a cost-efficient and environmental friendly method for upgrading existing pipelines with sufficient capacity. This study examines the possibility of applying no-dig to combined sewer systems (CS) with insufficient capacity. In this study, a concept assessment methodology that combines the analytical approaches from stormwater and sewer system assessments is presented. The methodology was tested on a case area that was part of an environmental project in Oslo, Norway. Three alternative concepts were examined; A0: no-dig and low impact development (LID), A1: no-dig, LID and green infrastructure (GI), and A2: CS up-sizing using open-cut methods. The study concludes that CS with insufficient capacity can be rehabilitated using no-dig if LID and GI. The combination of no-dig and LID reduces costs considerably but does involve the risk of damages from uncontrolled surface runoff. The main risk-reduction measure is the development of GI as an integrated stormwater management system that requires cross-sector collaboration within municipalities

Intensifying rehabilitation of combined sewer systems using trenchless technology in combination with low impact development and green infrastructure

Throughout Europe, there is a considerable need for investment in the upgrade of sewer systems – due to three main factors: ageing infrastructure, climate change and urban population growth. The need for investments is expected to grow significantly in the years ahead. Trenchless rehabilitation (no-dig) of sewer pipelines is a cost-efficient and environmental friendly method for upgrading existing pipelines with sufficient capacity. This study examines the possibility of applying no-dig to combined sewer systems (CS) with insufficient capacity. In this study, a concept assessment methodology that combines the analytical approaches from stormwater and sewer system assessments is presented. The methodology was tested on a case area that was part of an environmental project in Oslo, Norway. Three alternative concepts were examined; A0: no-dig and low impact development (LID), A1: no-dig, LID and green infrastructure (GI), and A2: CS up-sizing using open-cut methods. The study concludes that CS with insufficient capacity can be rehabilitated using no-dig if LID and GI. The combination of no-dig and LID reduces costs considerably but does involve the risk of damages from uncontrolled surface runoff. The main risk-reduction measure is the development of GI as an integrated stormwater management system that requires cross-sector collaboration within municipalities