Browsing by Author "Taylor, Craig A."

Now showing 1 - 8 of 8
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    Heating of shallow groundwater flow by conduction from a paved surface: Requirements for coldwater stream protection
    (St. Anthony Falls Laboratory, 2008-05) Taylor, Craig A.; Stefan, Heinz G.
    Temperatures of shallow groundwater depend on ground surface temperatures and water recharge temperatures. Important heat transfer processes that contribute to groundwater temperatures are conduction from the soil surface into the ground(water), infiltration of warm surface water, and advection by the horizontal flow in the aquifer. Shallow groundwater temperatures respond to ground surface temperatures and infiltration regimes. Both of these are modified by urban development and climate change. In this paper we explore concepts and relationships by which shallow groundwater temperature change can be analyzed or predicted. We estimate the projected seasonal temperature change in an aquifer of given depth, thickness and flow velocity (permeability) and below a vegetated (grassy) surface when a paved surface (parking lot) of given size is added on the ground surface. The analysis is in 2-D, and groundwater temperatures are simulated as a function of horizontal and vertical distance in the aquifer, and as a function of time of the year. Results are explained and presented in a form useful for practical applications, and examples are presented.
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    Heating of shallow groundwater flow by conduction from a paved surface: Requirements for coldwater stream protection
    (St. Anthony Falls Laboratory, 2008-05) Taylor, Craig A.; Stefan, Heinz G.
    Temperatures of shallow groundwater depend on ground surface temperatures and water recharge temperatures. Important heat transfer processes that contribute to groundwater temperatures are conduction from the soil surface into the ground(water), infiltration of warm surface water, and advection by the horizontal flow in the aquifer. Shallow groundwater temperatures respond to ground surface temperatures and infiltration regimes. Both of these are modified by urban development and climate change. In this paper we explore concepts and relationships by which shallow groundwater temperature change can be analyzed or predicted. We estimate the projected seasonal temperature change in an aquifer of given depth, thickness and flow velocity (permeability) and below a vegetated (grassy) surface when a paved surface (parking lot) of given size is added on the ground surface. The analysis is in 2-D, and groundwater temperatures are simulated as a function of horizontal and vertical distance in the aquifer, and as a function of time of the year. Results are explained and presented in a form useful for practical applications, and examples are presented.
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    Heating of shallow groundwater flow by conduction from a paved surface: Requirements for coldwater stream protection
    (St. Anthony Falls Laboratory, 2008-05) Taylor, Craig A.; Stefan, Heinz G.
    Temperatures of shallow groundwater depend on ground surface temperatures and water recharge temperatures. Important heat transfer processes that contribute to groundwater temperatures are conduction from the soil surface into the ground(water), infiltration of warm surface water, and advection by the horizontal flow in the aquifer. Shallow groundwater temperatures respond to ground surface temperatures and infiltration regimes. Both of these are modified by urban development and climate change. In this paper we explore concepts and relationships by which shallow groundwater temperature change can be analyzed or predicted. We estimate the projected seasonal temperature change in an aquifer of given depth, thickness and flow velocity (permeability) and below a vegetated (grassy) surface when a paved surface (parking lot) of given size is added on the ground surface. The analysis is in 2-D, and groundwater temperatures are simulated as a function of horizontal and vertical distance in the aquifer, and as a function of time of the year. Results are explained and presented in a form useful for practical applications, and examples are presented.
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    A Research Plan and Report on Factors Affecting Culvert Pipe Service Life in Minnesota
    (Minnesota Department of Transportation, 2012-09) Taylor, Craig A.; Marr, Jeff
    Culvert pipe material selection has traditionally been a relatively simple task involving metal or concrete pipe. In recent years, the addition of coated metal and plastic pipe has led the federal government to implement a rule requiring the consideration of alternative pipe materials. The current MnDOT Drainage Manual provides limited guidance on the selection of pipe material. The manual is lacking detailed information on the influence of environmental conditions on pipe durability in Minnesota. It is necessary to provide updated, accurate information on pipe material and durability for factors directly related to Minnesota. To reach this goal, the availability and suitability of existing data, as well as the practices associated with predicting pipe life spans must be evaluated. This report is the result of the initial feasibility study for a larger project(s) to update the MnDOT Drainage Manual. The goal for this report is to identify knowledge gaps, produce a research plan that will guide future research, and draw any pipe materials conclusions possible using the data available.
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    Shallow groundwater temperature response to urbanization and climate change in the Twin Cities Metropolitan Area: Analysis of vertical heat convection effects from the ground surface
    (St. Anthony Falls Laboratory, 2008-05) Taylor, Craig A.; Stefan, Heinz G.
    Groundwater temperatures, especially in shallow (quaternary) aquifers depend on ground surface temperatures which in turn depend on climate and land use. A key heat transfer processes that contributes to shallow groundwater temperatures is conduction from the soil surface into the groundwater. Groundwater temperatures therefore respond to ground surface temperatures. Ground surface temperatures have seasonal and diurnal cycles, and are modified by urban development, and climate change. In Minnesota seasonal temperature cycles penetrate the ground to depths on the order of 10 to 15m. In this report, we explore concepts and basic relationships by which groundwater temperatures are induced by conduction from the ground surface. Our analysis indicates that a fully urbanized downtown area at the latitude of Minneapolis/St. Paul is likely to have a groundwater temperature that is nearly 3°C warmer than an undeveloped/ agricultural area. Pavements are the main cause of this change. Data collected by the MPCA in the St. Cloud, MN area confirm that land use influences groundwater temperatures. Global warming will also result in a rise of ground surface temperatures and hence groundwater temperatures. In the extreme case of a 2xCO2 climate scenario groundwater temperatures would be expected to rise by up to 4°C. Compounding urbanization and climate change, by applying the extreme 2xCO2 climate scenario to a land use change from “undeveloped” to “fully urbanized”, is expected to raise groundwater temperatures by about 5°C at the latitude of Minneapolis/St. Paul. A mean annual groundwater temperature rise of 5°C would likely have a very adverse affect on trout habitat in coldwater streams in summer.
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    Third-Party Rating Curve Development and Debris Testing for Thirsty Duck® : TD Series Buoyant Flow Control Device
    (St. Anthony Falls Laboratory, 2013-02) Taylor, Craig A.; Hilsendager, Jon
    The University of Minnesota, St. Anthony Falls Laboratory (SAFL) was contracted by Thirsty Duck, Ltd to conduct a testing program on a series of buoyant flow devices (BFDs). The focus of the study was to develop rating curves and analyze performance under extreme debris loading conditions for the TD series line of BFDs. The models tested include the TD248-48, TD246-48, and TD244-48. Performance under debris load was evaluated using a mixture of leaves, grass (hay), and aluminum cans. The discharge rate was monitored during the debris performance tests to determine if the debris impaired the function of the device. Figure 1 contains a concept diagram of the TD system. Major device components include an orifice to control discharge, a float to suspend the orifice at a fixed distance below the water surface, a skimmer to prevent fouling, and an expanding conduit ("bellows") to convey water from the orifice to the outlet pipe. The device is designed to connect to the outlet pipe with a standard 150# ANSI flange connection. The three devices tested differ in their orifice and bellows diameters; however, the bellows length for each was the same. Device specifications are provided in Table 1.
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    Third-Party Rating Curve Development and Debris Testing for Thirsty Duck® TDP Series Floating Outlet and Skimmer
    (St. Anthony Falls Laboratory, 2014-02) Taylor, Craig A.
    The University of Minnesota, St. Anthony Falls Laboratory (SAFL) was contracted by Thirsty Duck, LP to conduct a testing program on a series of floating outlets and skimmers. The purpose of the study was to develop rating curves, conduct a freezing test, and analyze performance under extreme debris loading conditions for their TDP series product. The models tested include the TDP-248 and TDP-184. An additional hydrostatic pressure test was conducted on the 8-inch bellows component of the TDP-248. Performance under debris load was evaluated using a mixture of grass (hay), cans, plastic bottles, plastic bags, and rope. The discharge rate was monitored during the debris performance tests to determine if the debris impaired the function of the product. A freeze test was also performed on a TDP-248 with an 8-inch bellows. The results of the rating curve experiments were used by Thirsty Duck, LP to calibrate their analytic model for predicting flow rates. The TDP products are designed to connect to the outlet pipe with a standard 150# ANSI flange connection. Figure 1 contains a concept diagram of the TDP system. Major components include an orifice to control discharge, a float to suspend the orifice at a fixed distance below the water surface, a skimmer to prevent fouling, and an expanding conduit ("bellows") to convey water from the orifice to the outlet pipe. The orifice is cut from a conical plenum that connects the float to the bellows. This allows the orifice to be custom sized by the installer. Both floating outlet and skimmers were tested for multiple orifice sizes. Testing specifications are provided in Table 1.