Browsing by Author "Hozalski, Raymond M."
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Item Assessment of Stormwater Best Management Practices(University of Minnesota, 2008-04) Anderson, James L.; Asleson, Brooke C.; Baker, Lawrence A.; Erickson, Andrew J.; Gulliver, John S.; Hozalski, Raymond M.; Mohseni, Omid; Nieber, John L.; Riter, Trent; Weiss, Peter; Wilson, Bruce N.; Wilson, Matt A.; Gulliver, John S.; Anderson, James L.Item Combined UMN-MPCA 2014-2017 lake data on Secchi depth, CDOM, Chlorophyll and total suspended solids(2019-01-15) Brezonik, Patrick L; Hozalski, Raymond M.; Finlay, Jacques C; brezonik@umn.edu; Brezonik, Patrick L; University of Minnesota Water Quality by Remote Sensing GroupThis file contains approximately 1460 records on four water quality variables measured on near-surface water samples of lakes in Minnesota (primarily) and also in Wisconsin and Michigan collected by our research group from 2014 to 2017 and similar data collected by the Minnesota Pollution Control Agency in its annual lake water quality assessment program from 2015 to 2017. The variables are Secchi depth (SD), colored dissolved organic matter (CDOM) measured as the Napierian light absorption coefficient at 440 nm, chlorophyll-a, and total suspended solids concentrations. The database was used for a published paper to analyze the effects of CDOM on SD and show that high CDOM levels limit light penetration and thus SD in colored lakes.Item The development and application of a four-level rain garden assessment methodology(St. Anthony Falls Laboratory, 2007-11) Asleson, Brooke C.; Nestingen, Rebecca S.; Gulliver, John S.; Hozalski, Raymond M.; Nieber, John L.The Minnesota Pollution Control Agency (MPCA) and the Metropolitan Council Environmental Services (MCES) provided funding for this project. The involvement of the project manager from the MPCA, Bruce Wilson, and the project officer from MCES, Jack Frost, was greatly appreciated. The Technical Advisory Panel (TAP) for the project whom provided insightful and experienced advice throughout the project added to the usability of the final product. The assistance of several undergraduate students’ Geoff Kramer, Nicolas Olson, and Thomas Natwick was undoubtedly a critical component leading to the final outcome of this project. Their hard work is very much appreciated. The staff at St. Anthony Falls Laboratory (SAFL) provided assistance in the construction of equipment necessary for this project. University of Minnesota facilities management and the City of Little Canada provided assistance with the use of fire hydrants for this research. Several partnerships were developed through this project and provided additional insight to this work. I would like to thank the Ramsey Washington Metro Watershed District (RWMWD) for their enthusiastic involvement with this project, especially Cliff Aichinger who also served on the TAP. The Dakota County Soil and Water Conservation District and Washington County Conservation District were conducting similar work and the cooperation of our efforts aided in the successfulness of this work.Item Domestic Use Technical Work Team Report: Minnesota Water Sustainability Framework, January 2011(University of Minnesota. Water Resources Center, 2011-01) Edgerton, Dan; Hozalski, Raymond M.Item Performance Assessment of Underground Stormwater Treatment Devices(St. Anthony Falls Laboratory, 2007-07) Wilson, Matthew A.; Gulliver, John S.; Mohseni, Omid; Hozalski, Raymond M.Proprietary underground devices are often used for stormwater treatment in urban areas due to tight space constraints. Most of these devices are designed to remove suspended solids from stormwater runoff prior to discharge into lakes, rivers, and streams via the physical separation process of sedimentation. Data on the performance of installed devices are limited and existing data are questionable because of the problems associated with assessment via monitoring. The objectives of this research were to: (1) investigate the feasibility and practicality of field testing for assessing the performance of underground devices, (2) evaluate the effects of sediment size and stormwater flow rate on the performance of four devices from different manufacturers, and (3) develop a universal approach for predicting the performance of a device for any given application. For the field testing, a controlled and reproducible synthetic storm event containing sediment of a fixed size distribution and concentration is fed to a pre-cleaned device. The captured sediment is then removed, dried, sieved, and weighed. Universal performance models were developed from the results of this work and parallel laboratory testing of two other full-scale devices using the Peclet number, which explains two major processes in performance: (1) advection or settling of particles and (2) turbulent diffusion or resuspension of particles. The universal performance models will improve the selection and sizing of these devices and their overall performance after installation.Item Performance Assessment of Underground Stormwater Treatment Devices(Minnesota Department of Transportation, 2007-11) Wilson, Matthew; Gulliver, John S.; Mohseni, Omid; Hozalski, Raymond M.The objectives of this research were threefold: to investigate the feasibility and practicality of field testing to assess the performance of underground devices used for stormwater treatment in urban areas; evaluate the effects of sediment size and stormwater flow rate on the performance of four different manufactured devices; and to develop a universal approach for predicting the performance of a device for any given application. Field testing that used a controlled and reproducible synthetic storm event that contained sediment of a fixed size distribution and concentration fed to pre-cleaned devices led to the development of uniform performance models. The results of this project show that controlled field tests are a practical, robust and accurate means of determining an underground device's performance, based on solid size distribution and density of the influent, in addition to water discharge and temperature. This premise was successfully verified in field tests on four devices and in laboratory tests on two devices. The resulting protocol and results of testing will be a useful tool for consultants, manufacturers, local governments, and state agencies for selecting, sizing, and evaluating stormwater treatment technologies to protect water resources.Item Preliminary Laboratory Investigation of Enzyme Solutions as a Soil Stabilizer(2005-06-01) Marasteanu, Mihai O; Hozalski, Raymond M.; Clyne, Timothy R.; Velasquez, RaulThis research studied the effect of two enzymes as soil stabilizers on two soil types to determine how and under what conditions they function. Researchers evaluated the chemical composition, mode of action, resilient modulus, and shear strength to determine the effects of the enzymes A and B on the soils I and II. The enzymes produced a high concentration of protein and observations suggest the enzymes behave like a surfactant, which effects its stabilization performance. The specimens were subjected to testing of varying lengths of time to determine their performance. Researchers observed an increase in the resilient modulus as the curing time increased but that an increase in application rate, as suggested by manufacturers, did not improve the performance of the enzymes. The study also suggests noticeable differences between the two enzymes and their effects on the soils in terms of resilient modulus and the stiffness of the soil.Item Sorption and Release of Dissolved Pollutants Via Bioretention Media(St. Anthony Falls Laboratory, 2011-09) Morgan, Joel G.; Paus, Kim A.; Hozalski, Raymond M.; Gulliver, John S.The removal and retention of cadmium, copper, and zinc is investigated with batch and column experiments of compost and sand using synthetic stormwater. The maximum sorption capacities found using the Langmuir isotherm equation for Cd and Zn are 2.13 mg/g and 3.82 mg/g for compost and 0.02 and 0.07 mg/g for sand. Copper precipitates at the solution pH and could not be modeled. Column studies using three different ratios of compost (50, 30, 10, and 0%, by bulk volume) in sand were conducted to develop breakthrough curves. The sorption capacities for 15 cm of filter media found using the Thomas Model are 0.78, 0.37, 0.23, and 0.07 mg Cd/g for 50%, 30%, 10% and 0% compost, respectively. The column study results were used to predict bioretention lifespan. At stormwater concentrations, 15 cm of filter media composed of 30% compost and 70% sand will last 95 years until breakthrough, when the effluent concentration is 10% of the influent concentration. In both batch and column studies, effluent concentrations of phosphorus exceeded the influent concentrations indicating phosphorus export from the filter media to receiving waters. The release of phosphorus was initially high, but then decreased to a steady state value of 0.29 mg/L (C0=0.13 mg/L) and remained constant throughout the test. The total yearly load exported from a typical bioretention practice containing 30% compost is estimated at 347 mg dissolved phosphorus per year. Lastly, the results are discussed in relation to stormwater management operation and maintenance. Over time, toxic metals will continue to migrate down through the filter media. Influxes of new toxic metals and the release of toxic metals by degrading compost will cause the concentration in the filter media to increase. The removal of phosphorus is dependent on the background level of phosphorus on the chosen filter media and, based on the column study results, may continue to release from the filter media at a constant rate. Bioretention practices composed of MNDOT Grade 2 compost and C‐33 sand may be a source of phosphorus to receiving waters. Thus, a novel recommendation for bioretention redesign is made that will enable us to better design infiltration practices for protection of receiving ground and surface waters by retaining both dissolved toxic metals and phosphorus.