Browsing by Subject "Hydraulic Conductivity"

Now showing 1 - 3 of 3
  • Thumbnail Image
    Item
    Geospatial Analysis of Transmissivity and Hydraulic Conductivity Across Minnesota: Using the County Well Index and Specific-Capacity Data
    (2022-12) Full, Jonathan
    Numerous hydrogeologic studies have been performed across Minnesota; however, they focus on small regions of the state. The Minnesota Conductivity Calculator (MCC) was developed to better observe spatial variations in hydraulic conductivity. This work strives to capture the variations of hydraulic conductivity across a variety of domains, scaling from a small neighborhood of wells to large provinces spanning across the state. The MCC leverages data from the Minnesota County Well Index (CWI) to determine transmissivity and hydraulic conductivity at 170,975 wells. Then, lognormal ordinary kriging was performed with the hydraulic conductivity data to visualize spatial variations. The MCC can be used to efficiently produce maps of hydraulic conductivity across the state, which is useful for a number of groundwater management purposes, including groundwater modeling.
  • Thumbnail Image
    Item
    Soil health system impacts on soil hydraulic functions in southern Minnesota
    (2023-12) Tangen, Bailey
    Soil health management systems use agricultural practices incorporating living roots, persistent surface cover, diverse crop rotations, and minimal soil disturbance. These systems are widely believed to improve soil hydraulic functions. However, intense rainfall can cause physical slaking of aggregates, loss of surface pores, and reduced hydraulic functions. Soil health management systems correlate with stable aggregates and large soil pores, but it is not clear how these properties change with rainfall in fine-textured soil profiles in southern Minnesota, United States. Therefore, quantifying the hydraulic function of these systems is important as climate change intensifies growing season rainfall. Here, we investigated soil health system’s volumetric soil water content and aggregates’ response to rainfall. During 2021 and 2022, we collected data from five tillage and cover crop treatments in replicated plots at the Southern Research and Outreach Center in Waseca, MN, and paired conventional and soil health systems at three long-term on-farm sites (≥5 years, clay loam and silt loam soils). We monitored volumetric soil water content and soil aggregates within 24 hours before and 24 and 72 hours after select rainfall events. Across all locations, drier conditions led to greater rainfall capture. Differences in response to rain were found between the paired farm treatments. Generally, conventional sites had 5-20% more small aggregates following rain than soil health sites, but this effect was inconsistent across all locations. Soil health systems generally retained 10-30% more large water-stable aggregates than conventional systems in response to rain. Based on soil water retention curves, soil health treatments trended 2.5-12.5% more macroporosity than conventional systems, likely contributing to the water capture. At the farms, greater microporosity and connectivity led to 0.25-2 cm/hr greater unsaturated hydraulic conductivity relative to soil health sites, validating the greater macroporosity results we found in the soil health sites. Despite long-term treatment history at SROC, there was no unsaturated hydraulic conductivity difference, though trends showed a positive relationship with increased disturbance, like rip/chisel. Soil health indicators were higher for the soil health system of one on-farm site, where soil health practices included 30 years of long-term no-till and cover crops compared to moldboard plowing. This research indicates the importance of holistically incorporating soil health practices into field systems for achieving soil functions.
  • Thumbnail Image
    Item
    Utilizing Waste Material From Minnesota For Stormwater Management Purposes
    (2024-05) Amoateng, Godbless
    Minnesota's mineral, forestry, agriculture, and industrial activities generate substantial by-products and waste. Strategies to reuse or recycle these can reduce landfill waste, enhance public health, conserve resources, and cut costs and emissions. Building on the frameworks by Johnson et al. (2017), Saftner et al. (2019), and Saftner et al. (2022), this project extended its scope across Minnesota to include materials like dredge sediment from Mississippi River, RCA (recycled concrete aggregate) and VersaLime. Researchers identified, selected, and characterized various waste, by-products, and commercial materials statewide and tested engineered soil mixes for roadway foundations, assessing their stormwater retention and support for native plants. Laboratory methods characterized these mixes, which were implemented and evaluated in situ. A preliminary environmental life cycle assessment was also conducted, quantifying the environmental impacts of the engineered soil mixtures. Results were compiled into a design guide for the Minnesota Department of Transportation (MnDOT) engineers.