Kranz, C N (2021) Optimizing compost incorporation for stormwater infiltration, runoff quality, and vegetation establishment in post-construction soils. PhD thesis, North Carolina State University, USA.
Abstract
Urbanization can degrade the natural function of soil through stripping of topsoil, vegetation removal, and compaction by heavy equipment. The result is an exposed, compacted subsoil with low fertility and infiltration, which leads to increased erosion and sediment loss, and impedes vegetation establishment. Strategic compost incorporation to disturbed, degraded urban soils may provide benefit to soil properties. A progression of experiments were conducted to determine the optimal compost incorporation rates to improve stormwater infiltration, runoff quality, and vegetation establishment. Two laboratory-scale experiments investigated the effect of compost incorporation rate on (1) saturated hydraulic conductivity (Ks) and (2) pollutant export patterns. First, results from the Ks experiments demonstrated that level of soil compaction (soil porosity) was a more important factor than compost rate for determining Ks. Compacted, low porosity soils with 50% compost by volume had significantly reduced Ks compared to medium and high porosity soils with no compost. Second, results from pollutant export experiments show stormwater largely did not increase the pollutant loads compared to DI water with compost incorporation. Additionally, results from adsorption and desorption experiments show compost-soil blends have a high capacity to sorb and retain pollutants. Next, a greenhouse experiment considered vegetation quantity and quality with varying rates of compost. There were no differences in the timeliness of vegetation germination between treatments. Higher rates of compost were found to have more vegetation cover and produce more biomass. Lastly, a field experiment determined the effects of compost incorporation on stormwater runoff, runoff quality (sediment loss and pollutant loads), infiltration rate (IR), and vegetation establishment over the course of a growing season. Compost incorporation did not alter runoff quantity or quality compared to a tilled, no compost treatment. More vegetation biomass was produced in compostamended treatments compared to treatments without compost incorporation. Overall, the results of these studies suggest that the direct impact of tillage on soil properties is the primary factor affecting stormwater movement through soil. Compost incorporation may be beneficial to improve vegetation coverage, which is necessary for long-term erosion control. Tillage appears to be a viable option for reducing runoff volumes in compacted soils.
| Item Type: | Thesis (Doctoral) |
|---|---|
| Thesis advisor: | McLaughlin, R A and Heitman, J L |
| Uncontrolled Keywords: | urbanization; equipment; stormwater; erosion control; export; experiment |
| Index terms: | hydraulic, export, option, subsoil, infiltration, urbanization, stormwater, conductivity, pollutant, movement, laboratory, erosion control, experiment |
| Subjects: | fluid mechanics, data collection methods, decision analysis, environmental health, environmental engineering, material properties and characteristics, urban planning, environmental science, economic analysis, materials science, health behaviours and lifestyles, research management, land management |
| Topics: | Research Practice, Construction Materials, Business Strategy, Governance, Engineering Principles, Sustainability, Risk Management |
| Descriptive scope: | 3 PCE |
N.B. Descriptive scope is a count of how many of the five facets of empirical research are indicated by the words used in title, abstract and keywords. It is not intended as a judgement on the research; merely a count of the kind of word we would expect to indicate Phenomenon, Concepts, Theoretical framing, Empirical techniques, Analytical techniques. If all five are present, then a code of “5 PCTEA” will indicate this. If you feel the coding for this record is questionable, we welcome discussion around the terms we matched or the way we categorized them. The facet you would expect may not be coded, or a facet may be coded inappropriately. This can also bear on a larger question, of which facets should be treated as defining in construction management research. Please get in touch, and we will look at it. More details here