Landfill cap models under simulated climate change precipitation: impacts of cracks and root growth

Sinnathamby, Gowthaman; Phillips, Debra; Sivakumar, V.; Paksy, A.

doi:10.1680/geot.12.p.140

Cited by 38 publications

(7 citation statements)

References 23 publications

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“…changes in hydraulic conductivity as they close, as shown by Sinnathamby et al (2014) in a study of a vegetated landfill cap. It should also be noted that each test alters the moisture conditions and degree of saturation at the test location as discussed above and this effect is incorporated in the observed behaviour on re-testing.…”

Section: Temporal Variabilitymentioning

confidence: 80%

In situ measurements of near-surface hydraulic conductivity in engineered clay slopes

Dixon

Crosby

Stirling

et al. 2018

QJEGH

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In situ measurements of near-saturated hydraulic conductivity in fine grained soils have been made at six exemplar UK transport earthwork sites: three embankment and three cutting slopes. This paper reports 143 individual measurements and considers the factors that influence the spatial and temporal variability obtained. The test methods employed produce near-saturated conditions and flow under constant head. Full saturation is probably not achieved due to preferential and bypass flow occurring in these desiccated soils. For an embankment, hydraulic conductivity was found to vary by five orders of magnitude in the slope near-surface (0 to 0.3 metres depth), decreasing by four orders of magnitude between 0.3 and 1.2 metres depth. This extremely high variability is in part due to seasonal temporal changes controlled by soil moisture content, which can account for up to 1.5 orders of magnitude of this variability. Measurements of hydraulic conductivity at a cutting also indicated a four orders of magnitude range of hydraulic conductivity for the near-surface, with strong depth dependency of a two orders of magnitude decrease from 0.2 to 0.6 metres depth. The main factor controlling the large range is found to be spatial variability in the soil macro structure generated by wetting/drying cycle driven desiccation and roots. The measurements of hydraulic conductivity reported in this paper were undertaken to inform and provide a benchmark for the hydraulic parameters used in numerical models of groundwater flow. This is an influential parameter in simulations incorporating the combined weather/vegetation/infiltration/soil interaction mechanisms that are required to assess the performance and deterioration of earthwork slopes in a changing climate.

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Section: Temporal Variabilitymentioning

confidence: 80%

In situ measurements of near-surface hydraulic conductivity in engineered clay slopes

Dixon

Crosby

Stirling

et al. 2018

QJEGH

View full text Add to dashboard Cite

show abstract

“…The presence of vegetation and its evapotranspiration has been recognised to affect the hydrology of the vadose zone of some civil engineering systems, such as embankments, slopes and landfill covers (Scanlon et al, 2005;Smethurst et al, 2006Smethurst et al, , 2015Leung & Ng, 2013;Sinnathamby et al, 2013). Plant evapotranspiration could directly affect the magnitude and distribution of moisture content and suction in the vadose zone.…”

Section: Introductionmentioning

confidence: 99%

Effects of planting density on tree growth and induced soil suction

Leung

et al. 2016

Géotechnique

119

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Plant evapotranspiration is recognised to affect soil suction of slopes and landfill covers. Previous work has focused on evapotranspiration-induced suction by a single plant, with little attention paid to the effects of planting density. The aim of this study is to quantify any changes in tree growth and tree-induced suction during evapotranspiration and rainfall under different planting densities for non-mixed-species plantations. A tree species, Schefflera heptaphylla, which is commonly found in Asia, was planted in silty sand at spacings of 60, 120 and 180 mm, representing three different planting densities. For each case, three replicates were tested to consider tree variability. In total, the responses of suction for 297 seedlings subjected to drying and a rainfall event with a 10-year return period were measured. The test results show that reducing the tree spacing from 180 to 60 mm induced greater tree-tree competition for water, as indicated by a 364% increase in peak suction upon evapotranspiration. Such tree-tree interaction led to: (a) a 19-35% reduction in the leaf area index; (b) a 17-36% decrease in root length; and (c) an obvious decay of roots. Upon the rainfall event, the infiltration rate for vegetated soil with trees planted at a spacing of 60 mm was up to 247% higher than those for soil with a wider tree spacing, where mainly fresh roots were found. Although most suction within the root zone (i.e. top 100 mm) was lost due to increased infiltration at 60 mm spacing, suctions in deeper depths below root zone were largely preserved.

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“…Using an intersectional interpretive framework to understand these analyses, we argue that such findings could evidence sites of resistance and forms of power by Black, Indigenous, and women of color to environmental injustices and risks (Mann, 2011;Ducre, 2018;Perkins, 2021) which may explain the unexpected finding. Such an interpretation could have implications for climate risks both in how landfills contribute to global warming through methane emissions and in how landfills are not "climate ready"-that is they are not designed to withstand shocks anticipated from increased disaster frequency and severity due to the global climate crisis (e.g., Weber et al, 2011;Sinnathamby et al, 2014;Wille, 2018;Beaven et al, 2020).…”

Section: Interactive Effectsmentioning

confidence: 99%

Intersectional and Entangled Risks: An Empirical Analysis of Disasters and Landfills

Cannon

2021

Front. Clim.

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Landfills are environmental hazards linked to harms, such as the production of greenhouse gases and the accumulation of toxins in natural and human systems. Although environmental justice research has established such unwanted land uses as hazardous waste sites occur in poor communities and communities of color, less is known about the relationship between landfills and gender. As a driver of global climate change, there is also limited research into the relationships among disasters, landfills, and climate-related risks. To fill this gap, the current study uses an intersectional approach to theorize and empirically analyze relationships among landfills, disasters, race, class, and gender. We employ negative binomial regression to analyze a unique U.S. dataset of landfill counts, total number of disasters, and socio-demographic characteristics, including the use of two-way interactions among race, sex, and socioeconomic status variables, and number of federally-declared disasters that influence landfill counts. Findings suggest that intersecting axes of social location (specifically gender and race) are not multiplicative when it comes to landfills or the environmental risks they pose, but we argue may be entangled—that is related in non-linear and complicated ways. Using intersectionality theory, we interpret the findings to indicate that women of color are agents of resistance enacting their own forms of power against dominant structural arrangements that produce and maintain environmental injustices. Conclusions and implications for environmental justice, intersectionality, and climate risks are further discussed.

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Landfill cap models under simulated climate change precipitation: impacts of cracks and root growth

Cited by 38 publications

References 23 publications

In situ measurements of near-surface hydraulic conductivity in engineered clay slopes

In situ measurements of near-surface hydraulic conductivity in engineered clay slopes

Effects of planting density on tree growth and induced soil suction

Intersectional and Entangled Risks: An Empirical Analysis of Disasters and Landfills

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