Thesis
Investigating the influence of precipitation patterns and soil composition on soil moisture retention in physical models of green stormwater infrastructure
Master of Science (M.S.), Drexel University
Sep 2018
DOI:
https://doi.org/10.17918/D8V37V
Abstract
Green Stormwater Infrastructure (GSI) is a rapidly evolving means of managing the excess precipitation generated on impervious surfaces. Though GSI is still in the early stages of development and implementation, this study seeks to optimize performance during precipitation events using scaled-down, GSI prototypes located outdoors. Two types of loamy sand, Standard Stormwater Soil (SSS) and High Sand Blend Stormwater Soil (HSS), were placed atop gravel in rain barrels (hydraulic loading ratio 1:1) to model GSI construction. Barrels were placed on platform scales to record mass, while two soil moisture sensors were placed inside the barrels (the first at 6cm depth and the second at 20cm depth) to take measurements once per minute over a span of 40 precipitation events (March to August). A weather station was also on site to collect precipitation and temperature data once per minute over the same span of events. Through manipulation of this continuous data, discrete values were calculated to describe the data in terms of precipitation characteristics, soil moisture, infiltration, mass changes, and moisture retention. Correlation charts and full model stepwise regression equations were then used to relate the dependent variables of change in soil moisture and change in mass to other precipitation, temperature, and soil moisture variables. These data show that antecedent moisture conditions, the deeper soil moisture sensors, and the total amount of precipitation are indicative of the overall soil moisture changes during and after an event. Specific to the HSS, precipitation travels through the GSI quickly, in comparison to SSS which retains more moisture for a slower release of precipitation over time. Overall, both bare soils are useful for use in this particular model of GSI and should be tested in more extreme conditions, with larger hydraulic loading ratios, and using outflow measurement devices as well.
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Details
- Title
- Investigating the influence of precipitation patterns and soil composition on soil moisture retention in physical models of green stormwater infrastructure
- Creators
- Katelyn Rose Johnson - DU
- Contributors
- Franco Montalto (Advisor) - Drexel University (1970-)
- Awarding Institution
- Drexel University
- Degree Awarded
- Master of Science (M.S.)
- Publisher
- Drexel University; Philadelphia, Pennsylvania
- Number of pages
- viii, 52 pages
- Resource Type
- Thesis
- Language
- English
- Academic Unit
- Civil/Architectural/Environmental Engineering (1970-2026); College of Engineering (1970-2026); Drexel University
- Other Identifier
- 8040; 991014632712704721