Browsing by Subject "Slopes"

Now showing 1 - 3 of 3
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    Compaction Remediation for Construction Sites
    (Minnesota Department of Transportation, 2008-01) Chaplin, Jonathan; Min, Min; Pulley, Reid
    The goal of this project is to develop a sub-soiling regimen that will enhance and be compatible with existing erosion control measures. This project is important in minimizing the effect of construction-induced compaction on the urban and rural landscape. This activity, if successful, will become a building block for use in Best Management Practices (BMPs) that will ensure full vegetative growth post construction, and save on the cost of reapplication of erosion control measures. For a good comparative study, several sites were selected for typical slope and soil type. The study shows that there are low cost benefits to deep tillage of ROW. Heavy clay soils are problematic in that improvements in infiltration could not be detected after a single tillage operation. In lighter sandy soils, the benefits of tillage are such that significant increases in infiltration can be gained following a single pass tillage operation. The differences in tillage implement used could not be detected. The post-tillage aesthetic appeal when using a non-inverting plow (Kongskilde Paraplow) was apparent in this study. The vegetation was largely undisturbed following tillage, and this would be beneficial in preventing erosion on slopes. The ripper and the DMI inverted more soil, and therefore the tillage operation was less appealing to motorists. The relatively low cost of ownership and operation for the tillage is overshadowed by the high land cost when new roads are constructed. Tillage would be beneficial on lighter soils, however the "utility congestion" that is likely in such a scenario would make machinery management difficult.
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    Comparing Properties of Water Absorbing/Filtering Media for Bioslope/Bioswale Design
    (Minnesota Department of Transportation, 2017-11) Johnson, Kurt; Cai, Meijun; Patelke, Marsha; Saftner, David; Swanson, Josh
    Drainage from highways, particularly the first flush of runoff, contains high levels of contaminants such as suspended solids, metals, and organics. To restrict the discharge of polluted stormwater, the National Pollutant Discharge Elimination System (NPDES) State Disposal System (SDS) General Permit issued by Minnesota Pollution Control Agency (MPCA) in 2013 requires that the first inch of stormwater runoff from new impervious should be held on site through infiltration, harvesting or reuse. Multiple types of infiltration materials have been studied in the laboratory and the field, but few studies have considered the application of local materials for best management practices (BMP). The objective of this project is to determine the characteristics of various naturally occurring water adsorbing and filtering media, such as peat and muck, found along road construction projects in northern Minnesota. Salvage and reuse of these materials during road construction will be evaluated for stormwater treatment, including absorption, infiltration, filtration, and pollutant capture, in constructed vegetated slopes along highway right of ways. The naturally occurring material will be compared to leaf and grass feedstock compost.
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    Performance Assessment of Oversized Culverts to Accommodate Fish Passage
    (Minnesota Department of Transportation Research Services Section, 2011-08) Hansen, Brad; Johnson, Sara; Nieber, John L.; Marr, Jeff
    In Minnesota there is not a standard culvert design used at road crossings to improve aquatic organism or fish passage. The design process for fish passage in Minnesota is currently based on the knowledge and experience of local county, state and DNR personnel. The design methodology attempts to maintain the natural stream dimensions, pattern and profile through the culvert crossing. If designed properly aquatic organisms and fish that can make it upstream to the culvert should be able to pass through the culvert. This research was conducted to better understand the hydraulic conditions related to the practice of recessing culverts and other fish passage design elements over a range of landscapes in Minnesota. The design elements analyzed included bankfull width, slope, channel materials, side barrels and recessed culverts. Nineteen culvert sites were survey around the state. The main criterion used to evaluate performance of the culverts was the presence or absence of adequate sediment in the recessed culvert barrel. Six of the fourteen sites with recessed barrels had no sediment accumulation. A likely reason that these culverts lack sediment was increased velocities due to improper sizing relative to bankfull channel width and the accumulation of sediment in the side barrels. Wider Rosgen “C” type channels also correlated with performance issues related to culvert design.