Browsing by Subject "Stormwater"

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Analysis of Infiltration and Overland Flow over Sloped Surfaces: Application to Roadside Swales
(2017-06) Garcia de la Serrana Lozano, Maria Del Carmen
Environmental impacts and regulatory requirements associated with highway runoff present design challenges. Roadside swales, or drainage ditches, improve water quality by infiltration, filtration, and sedimentation. Road runoff volume reduction through infiltration occurs as the water flows over the side slope, acting as a filter strip, or down the length of the swale channel. Therefore, roadside swales are practical solutions that can mitigate the effect that linear transportation projects have on water bodies. This dissertation advances the understanding of the infiltration performance of roadside swales for design and planning purposes. The main objectives of this thesis are: understanding the overland flow and infiltration processes over a fraction of a slope, relating surface roughness parameters to the fraction of wetted area, and quantifying the effect of equidistant parallel strip water sources on the lateral component of infiltration. Moreover, this research leads to a better understanding of overland flow and infiltration in roadside swales through field experiments, and modeling efforts that can simulate how roadside swales operate. All the field tests, performed in four different highways, showed that water flow on the side slope of a roadside swale is concentrated in fingers, instead of sheet flow, at the typical road runoff intensities for which infiltration practices are utilized to improve surface water quality. The laboratory experiments aimed to formulate the relevance of fractal parameters, based on the Fourier power spectrum method, for understanding soil surface roughness, overland flow patterns, and erosion. A model has been developed for coupling a Green-Ampt-Mein-Larson infiltration submodel with kinematic wave submodels for both overland flow down the side slope and open channel flow for flow in the channel. The side slope of a roadside swale is the main part contributing to the loss of runoff by infiltration and the channel primarily conveys the water. Finally, a simplified roadside swale calculator has been developed with a reduced set of input parameters. The calculator can estimate the total percentage of annual volume infiltrated, supporting informed decision-making on how to account for the infiltration benefits of roadside swales.
Capturing Stormwater Nitrate and Phosphate with Sorptive Filter Media
(2017-07) Erickson, Andrew
Soluble phosphate and nitrate are more bioavailable than particulate forms. These nutrients result in eutrophication in both freshwater (typically phosphate-limited) and marine (typically nitrate-limited) systems. In addition, nitrate poses a public health risk at elevated concentrations in drinking water. This research shows that sand filters mixed with 5% iron filings captured, on average, 88% of the influent phosphate in laboratory experiments. Neither incorporation of iron filings into a sand filter nor capture of phosphate had a significant effect on the hydraulic conductivity. Pond-perimeter applications of iron enhanced sand filtration (IESF) with up to 10.7% iron by weight achieved between 29% and 91% phosphate reduction for five events within the first year of operation. After five years, however, a different pond perimeter IESF retained on average 26% of the influent phosphate over three rainy seasons. Retention was best for larger filtered volume events, but negative removal was observed for events with smaller filtered volume and low influent phosphate concentration. Non-routine maintenance improved the hydraulic performance of the pond perimeter IESF and, after a rinsing event, also improved phosphate retention rates to an average of 45%. An IESF was installed to treat agricultural tile drainage and found to reduce total phosphorus loads by 42% to 95% with a flow-weighted mean reduction of 66.3% ± 6.7% (a = 0.05) for 20 events in 2016. The phosphate load reduction varied from 9% to 87% with a flow-weighted mean reduction of 63.9% ± 7.7% (a = 0.05) for 31 events in 2015 and 2016. This research also shows that nitrate is captured abiotically by granular activated carbon (GAC) in laboratory experiments designed to mimic urban and agricultural stormwater runoff. The short contact time and inorganic characteristics of the influent synthetic stormwater suggest that the nitrate was captured by ion exchange, but (bi)carbonate may have competed with nitrate for capture by GAC. Abiotic capture of nitrate requires less stormwater storage volume and less residence time to remove nitrate compared to denitrification, and thus GAC could be used to design smaller treatment practices for nitrate removal.
Comparison of Biofiltration Media in Treating Industrial Stormwater Runoff
(2019-07) Isaacson, Kristofer
Biofiltration systems have become one of the most commonly used best management practices in dealing with stormwater runoff. Stormwater runoff is inherently variable, with the contaminants present depending greatly on the land use of the catchment basin. This study characterized the stormwater collected from an industrial site in northeastern Minnesota. It was determined the pollutants of concern for this site are dissolved heavy metals (Aluminum, Copper, Iron) and bacteria. Different media exhibit different strengths and weaknesses in the removal of pollutants in these biofiltration systems. As a result, there is not a universal combination of media that can adequately treat all stormwater. 18 bio-based media were tested in batch experiments to determine if they possessed any capacity for heavy metal removal. Eight media (APTsorb, bioAPT, biochar, marble, sand, vermiculite, and zeolite) that showed good removal were studied further in downward flowing column experiments. These column experiments determined that all materials demonstrated some capacity for dissolved metal removal with the exception of sand. However, marble performed the best by a significant margin, removing over 10 mg/cm3 of iron, 4 mg/cm3 of aluminum, and 2 mg/cm3 of copper. The four materials that were determined to have the largest removal capacity for heavy metals (APTsorb, compost, marble, zeolite) were tested in an additional column experiment in which the synthetic stormwater was inoculated with E. coli. Marble again performed the best removing 100% of E. coli throughout the duration of a 56-hour continuous flow column experiment. This characterization process provides valuable information on the effectivity and longevity of a variety of media in the design of future biofiltration systems.
Conservation Design Toolkit for LakeSuperiorStreams.org Stormwater Pollution Prevention Pilot Project
(University of Minnesota Duluth, 2006) Axler, Richard P; Schomberg, Jesse; Will, Norman; Reed, Jane; Lonsdale, David; Granley, Mindy; Hagley, Cynthia
Duluth, Minnesota has 43 named streams, 12 trout streams, and borders both pristine Lake Superior and the Duluth-Superior-Harbor Area of Concern. Duluth's storm water infrastructure includes 93 miles of streams and wetlands, and urbanization and rural development impact these waters by increasing runoff and velocity, temperature, turbidity and sediment, road salt, organic matter and nutrients. In 2002, an EPA (Environmental Monitoring for Public Access & Community Tracking) grant established a Partnership called DuluthStreams between the City of Duluth, University of MinnesotaDuluth professionals at the Natural Resources Research Institute and Sea Grant Program, and the Minnesota Pollution Control Agency and Western Lake Superior Sanitary District. Their goal was to enhance public understanding of streams and their connections to watershed land use by using real-time data and interpretive materials to illustrate the nature and consequences of degraded stormwater and its real costs to society. This has included issues associated with too much runoff such as flooding, with a key issue in the region being sanitary sewer overflows from infiltration and inflow (I&I). These events have imposed risks to public health and environmental risks to the coastal zone of Lake Superior and the Duluth-Superior Harbor, and required costly programs to reduce stormwater flows from key neighborhoods and construct storage tanks for temporary storage of stormwater enhanced sanitary sewer flows. The consequences of excess water and peak flows have also included excess sediment and turbidity, and potentially excess nutrients and pathogens. High salt concentrations for significant periods in late winter and early spring runoff from winter road and parking lot de-icing can present additional stress to trout and their prey. Increasing impervious surface and direct and indirect removal of riparian vegetation increases peak temperatures, especially during base flow periods creating additional periods of stress to cold water species with the additional potential stress of lowered dissolved oxygen. In 2003, sixteen governments and groups in the North Shore Region joined to form the Regional Stormwater Protection Team (RSPT). The Team's mission is to protect and enhance the region's shared water resources through stormwater pollution prevention by providing coordinated educational programs and technical assistance. One of the vehicles that the RSPT has harnessed for its stormwater education campaign is the DuluthStreams website as part of a regional effort to provide water pollution information to the public. The project has now expanded to now include 22 communities, agencies and organizations. In 2005 the website was re-named lakesuperiorstreams.org to reflect the broader geographic region that it represents in terms of climate, soils, quality of life, natural resources, the Lake Superior watershed, and culture. The website now averages more than 300,000 "hits"/month and >75,000 "page requests"/mo with a national target audience that includes: the general public; students and teachers; contractors, consultants and developers; decision makers; and agencies (local, state, and federal). Additional information is best found by examining http://lakesuperiorstreams.org.
Data for: Internal Loading in Stormwater Ponds as a Phosphorus Source to Downstream Waters
(2019-04-15) Taguchi, Vinicius J; Olsen, Tyler A; Natarajan, Poornima; Janke, Benjamin D; Gulliver, John S; Finlay, Jacques C; Stefan, Heinz G; ; taguc006@umn.edu; Taguchi, Vinicius J; University of Minnesota - St. Anthony Falls Laboratory - Stormwater Research Group
Stormwater ponds remove phosphorus through sedimentation before releasing captured water downstream. Internal loading can impair net phosphorus removal but is understudied in these highly modified systems. Using a combination of methods, we assessed the prevalence and potential causes of sediment phosphorus release in urban ponds. In a three-year, 98-pond dataset, nearly 40% of ponds had median water column total phosphorus concentrations exceeding the 95% confidence interval for runoff values (0.38 mg/L), suggesting widespread internal loading. In a subsequent intensive monitoring study of four ponds, strong stratification prevented spring and summer diurnal mixing, resulting in persistent hypolimnion anoxia (<1 mg/L dissolved oxygen). Incubated sediment cores from seven ponds demonstrated high anoxic phosphorus release. Sediment analysis revealed high labile organic and redox-sensitive phosphorus fractions with release potential at anoxia onset. Our analyses suggest phosphorus accumulated in stormwater ponds is highly sensitive to internal loading, reducing net removal and contributing to downstream eutrophication.
Determination of Effective Impervious Area in Urban Watersheds
(2015-08) Ebrahimian, Ali
Impervious surfaces have been identified as an indicator of the impacts of urbanization on water resources. The design of stormwater control measures is often performed using the total impervious area (TIA) in a watershed. Recent studies have shown that a better parameter for these designs is the " effective"� impervious area (EIA), or the portion of total impervious area that is hydraulically connected to the storm sewer system. Methods to improve estimates of EIA are not highly researched, and need further investigation. The overall goal of this project is to develop a method to estimate EIA in urban watersheds with data that is readily available. First, the existing rainfall-runoff method was improved by reducing the uncertainty associated with EIA estimates and applying it to 40 gauged urban watersheds with different sizes and hydrologic conditions, mostly in the Twin Cities metro area of MN and Austin, TX. The results are then utilized to develop a new method based on the integration of GIS and Curve Number (CN). The GIS-CN method is applicable to ungauged watersheds and is able to estimate EIA fraction based on TIA and hydrologic soil group (HSG). The results are used to evaluate the potential and the limitations of the GIS-CN method. The outcome and applications of this study improves the rainfall-runoff modelling in urban watersheds and will eventually lead to the design of a more sustainable urban stormwater infrastructure.
Development of Techniques to Quantify Effective Impervious Cover
(Center for Transportation Studies, University of Minnesota, 2011-09) Janke, Ben; Gulliver, John S.; Wilson, Bruce N.
Practitioners responsible for the design and implementation of stormwater management practices rely heavily on estimates of impervious area in a watershed. However, the most important parameter in determining actual urban runoff is the "effective" impervious area (EIA), or the portion of total impervious area that is directly connected to the storm sewer system. EIA, which is often considerably less than total impervious area and can vary with rainfall depth and intensity, is likely not determined with sufficient accuracy in current practice. A more accurate determination of EIA in a watershed would benefit a wide range of organizations involved in the design of stormwater management, pollution prevention, and transportation structures. This study investigated two existing methods of estimating EIA in a watershed: (1) analysis of large rainfall-runoff data sets using the method of Boyd et al. (1994), and (2) overlay analysis of spatial (GIS) data, including land cover, elevation, and stormwater infrastructure, using the method of Han and Burian (2009). The latter method provides an estimate of connected pavement, but requires the user to input the value of connected rooftop to determine the actual EIA value, which is the sum of these two quantities. The two methods were applied to two urban catchments within the Capitol Region Watershed in St. Paul, MN. The results were used to evaluate the potential of each method and make recommendations for future studies. In summary, the data analysis technique (Boyd et al., 1994) has the advantage of being quick and relatively simple to implement, as it did not require familiarity with specialized software tools (e.g. ArcGIS) and could be completed with any spreadsheet program with graphing capabilities (e.g. Excel). The EIA estimates from the data analysis are the most accurate, but the technique is unable to determine where in the watershed the EIA is located, and cannot be used if runoff discharge and local precipitation data is unavailable. By contrast, the GIS method (Han and Burian, 2009) has the advantage of being applicable to un-gauged watersheds, and also provides the location of EIA in the watershed. This latter feature makes it particularly attractive for honing the development and placement of BMP?s in a watershed. Unfortunately, the accuracy of the GIS method is completely dependent on the ability to faithfully represent the amount of roof connection in a watershed, a process that can add significant time and expense to the EIA estimate.
Duluth Residential Stormwater Reduction Demonstration Project for Lake Superior Tributaries
(University of Minnesota Duluth, 2011) Kleist, Chris; Brady, Valerie; Johnson, Lucinda B; Schomberg, Jesse
We used paired 2‐block street sections in the Amity Creek watershed (Duluth, MN) to demonstrate the effectiveness of homeowner BMPs to reduce residential stormwater flow to storm sewers in an older neighborhood in a cold climate on clay and bedrock geology. Runoff from each street was measured before and after installation of stormwater BMPs. In addition, the knowledge, attitudes, and practices of residents were measured before and after BMP installation. BMPs were installed on properties of willing residents of one street (“treatment”). Most residents (22 of 25 properties) willingly participated. 250 trees and shrubs were planted; 22 rain barrels were installed; 5 rain gardens, 12 rock‐sump storage basins, and 2 swales were constructed; and a stormwater ditch was re‐dug and had 5 ditch checks installed in it. The post‐project survey indicated an increase in understanding by treatment‐street residents of where stormwater flowed to and what it affected, and an increase in willingness to accept at least some responsibility for stormwater runoff. Residents who received BMPs were generally satisfied with them and would recommend them to others. Runoff reduction proved more difficult to quantify due to high and inconsistent runoff variability between the paired streets, very few pre‐BMP installation rain events, and loss of one control street due to re‐paving mid‐project. Capacity of installed BMPs is approximately 2.5% of the measured stormwater runoff. There is about a 20% greater reduction in runoff for the treatment street after BMPs were installed than for the control street for small to moderate storm events; while we would like to attribute this completely to our BMPs, we cannot prove that other factors weren’t also at work. Peak flows also appear to have been reduced for 1 inch and smaller rainstorms, but we were unable to accurately measure this reduction. The results are available on an existing stream education website and are used to educate neighborhood, city of Duluth, and regional residents on stormwater issues, individual responsibility, and BMP options.
Duluth Residential Stormwater Reduction Demonstration Project for Lake Superior Tributaries
(2011-07-30) Kleist, Chris; Brady, Valerie; Johnson, Lucinda B; Schomberg, Jesse
We used paired 2‐block street sections in the Amity Creek watershed (Duluth, MN) to demonstrate the effectiveness of homeowner BMPs to reduce residential stormwater flow to storm sewers in an older neighborhood in a cold climate on clay and bedrock geology. Runoff from each street was measured before and after installation of stormwater BMPs. In addition, the knowledge, attitudes, and practices of residents were measured before and after BMP installation. BMPs were installed on properties of willing residents of one street (“treatment”). Most residents (22 of 25 properties) willingly participated. 250 trees and shrubs were planted; 22 rain barrels were installed; 5 rain gardens, 12 rock‐sump storage basins, and 2 swales were constructed; and a stormwater ditch was re‐dug and had 5 ditch checks installed in it. The post‐project survey indicated an increase in understanding by treatment‐street residents of where stormwater flowed to and what it affected, and an increase in willingness to accept at least some responsibility for stormwater runoff. Residents who received BMPs were generally satisfied with them and would recommend them to others. Runoff reduction proved more difficult to quantify due to high and inconsistent runoff variability between the paired streets, very few pre‐BMP installation rain events, and loss of one control street due to re‐paving mid‐project. Capacity of installed BMPs is approximately 2.5% of the measured stormwater runoff. There is about a 20% greater reduction in runoff for the treatment street after BMPs were installed than for the control street for small to moderate storm events; while we would like to attribute this completely to our BMPs, we cannot prove that other factors weren’t also at work. Peak flows also appear to have been reduced for 1 inch and smaller rainstorms, but we were unable to accurately measure this reduction. The results are available on an existing stream education website and are used to educate neighborhood, city of Duluth, and regional residents on stormwater issues, individual responsibility, and BMP options.
DuluthStreams heads north: Making North Shore stream data make sense to citizens and local officials
(University of Minnesota Duluth, 2007-09-25) Axler, Richard P; Will, Norman; Host, George E; Henneck, Jerald; Lonsdale, David; Sjerven, Gerald; Reed, Jane; Ruzycki, Elaine; Hagley, Cynthia; Schomberg, Jesse; Carlson, Todd; Lonsdale, Marnie
The Duluth Streams website initially focused primarily within City of Duluth boundaries, but some of the streams that intersect Duluth originate in the surrounding communities of Hermantown and Proctor. In addition, Duluth and Superior share the St. Louis River watershed. The current project enabled us to fully expand the DuluthStreams website into a regional entity. It was built on a previous, but limited, Lake Superior Coastal Program Enhancement Fund effort to Minnesota Sea Grant at the University of Minnesota and partners that created web links to Proctor, Hermantown and Superior on the DuluthStreams website. This made these communities ideal as the first candidates for a regional expansion. As the project continued to evolve it became clear from discussions within the RSPT and with state agencies that there was a need to expand the focus area of the website to include the “greater Western Lake Superior” region and more specifically the Minnesota North Shore and Wisconsin South Shore in order to better manage Superior Basin water resources by supporting the mission of the RSPT regarding developing regional technical cooperation and collaboration, common educational materials, and presentation of case studies of successful stormwater designs. Minnesota streams draining into the Lake Superior coastal zone and St. Louis River Estuary are typically sensitive, low productivity, high-quality trout streams. Some (Miller, Amity, Lester, Talmadge, French, Poplar, Brule) are currently listed on the MN Clean Water Act (303d) List of Impaired Waters - most commonly for turbidity and Fish-Hg (MPCA 2006). Steep topography and thin, erodible soils make these streams particularly sensitive to development. Effective management and remediation of these streams requires an understanding of their physical, chemical, and biological characteristics, which can only be obtained by monitoring, particularly during storm and snowmelt runoff events, when the most dramatic impacts occur. These data are critical for developing and assessing BMPs, particularly in the face of increased development in the high growth watersheds along the North Shore of Lake Superior (e.g. Anderson et al. 2003; MPCA 2000; IJC 1999). MPCA initiated long-term monitoring of 6 critical streams along the North Shore in 2002. However, MPCA has lacked the resources to install automated water quality sensors, which are needed to capture critical pollutant loading events during high flows - important for developing cost-effective remediation and mitigation strategies.
DuluthStreams.org: Community Partnerships for Understanding Urban Stormwater and Water Quality Issues at the Head of the Great Lakes
(University of Minnesota Duluth, 2004-12) Axler, Richard P; Lonsdale, Marion; Reed, Jane; Hagley, Cynthia; Schomberg, Jesse; Henneck, Jerald; Host, George E; Will, Norman; Ruzycki, Elaine; Sjerven, Gerald; Richards, Carl; Munson, Bruce
This final report summarizes the accomplishments of the Duluth Streams Partnership from its inception through an EPA Environmental Monitoring for Public Access and Community Tracking (EMPACT) Program grant in January 2002 through September 2004. Duluth, Minnesota lies at the westernmost end of Lake Superior, the source and headwaters of the entire Laurentian Great Lakes ecosystem. Although perhaps better known for its extremely cold winters, Duluth residents and visitors know it as a city of forested hills, wetlands and trout streams with 42 named creeks and streams moving through the City in 30 subwatersheds. Duluth's park system is one of the most extensive in the nation, and the City owns and maintains 11,000 acres, including 125 municipal parks. Streams form the fabric of the aesthetic appeal and character of Duluth (Duluth Vision 2000), but are also the core of the City’s stormwater runoff system, with 250 miles of storm sewer, 93 miles of creek, 4,716 manholes, 2 lift stations, 13 sediment boxes, and over 138 miles of roadway ditches. Urbanization and rural development have placed increased pressure on the region’s coastal communities and on Duluth’s urban streams, in particular, on the 12 (with 2 more pending) that are designated as Trout Streams and 14 that are classified as Protected Waters. In addition, since the early 1990s, over 50 new lodging establishments were constructed along Lake Superior’s North Shore. One county located along the North Shore of Lake Superior (Cook) experienced a 24% population increase during that time. Stream communities of fish and amphibians and the invertebrates that sustain them are being adversely impacted by increased temperature, excessive turbidity and suspended solids, road salts, organic matter, and nutrients. Some of these streams have been placed on the Minnesota List of Impaired Waters, and several have been targeted for Total Maximum Daily Load (TMDL) development. Further, all of these streams discharge either directly into ultra-oligotrophic Lake Superior or indirectly via the St. Louis River Estuary- Duluth Superior Harbor. This is particularly important because Lake Superior has been designated as a zero-discharge demonstration project by the International Joint Commission for eliminating inputs of persistent toxic chemicals to the Great Lakes system. Second, the lake’s nearshore zone, the source of much of its biological productivity, is extremely nutrient deficient and sensitive to increased inputs of nutrients, suspended solids, turbidity, and organic matter. Lastly, the Harbor itself is one of the 43 Great Lakes Areas of Concern (AOCs) because of serious impairments to its beneficial uses. There are also significant social and economic impacts associated with this region - the Minnesota DNR reports that angling in North Shore streams and Lake Superior produces $63 million in direct sales and income and over 1,200 jobs. For North Shore streams alone, the numbers are over $33 million direct sales and income, and over 435 jobs. Stormwater issues have become increasingly important to resource and regulatory agencies and to the general public. In 1998 the City of Duluth established a stormwater utility to address the quality and quantity of surface water moving through the City and in 2003 was issued a Stormwater Permit under Phase II of the federal Clean Water Act’s National Pollution Discharge Elimination System (NPDES). Beginning in January 2002, under funding through EPA EMPACT in combination with in-kind effort from various agencies, the Natural Resources Research Institute (NRRI) and Minnesota Sea Grant formed a partnership with the City of Duluth, the Minnesota Pollution Control Agency (MPCA), the Great Lakes Aquarium, and the Western Lake Superior Sanitary District (WLSSD) to create Duluth Streams. Additional partners have since joined together to form a Regional Stormwater Protection Team (RSPT). The Partnership's chief goal is to enhance the general public's understanding of aquatic ecosystems and their connections to watershed land use to provide both economic and environmental sustainability. The project’s majors objectives were to: 1) link real-time remote sensing of water quality in four urban streams and GIS technology to current and historical water quality and biological databases (all 42 Duluth streams) using advanced data visualization tools in World Wide Web and information kiosk formats; 2) incorporate visually engaging interpretive text, animations and videos into the Duluth Streams website to illustrate the nature and consequences of degraded stormwater and the real costs to society; and 3) engage the public in the stormwater issue via programmatic activities such as establishing high school directed neighborhood stewardship and/or monitoring of 3 streams, developing curricula for high school and college students for inclusion in our Water on the Web curriculum, hosting a Duluth Streams Congress as a community forum for presenting all project results, and adapting the Nonpoint Education for Municipal Officials (NEMO) program to the greater Duluth Metropolitan Area. This final report summarizes the accomplishments of the Duluth Streams Partnership from its inception in January 2002 through September 2004. The website at htttp://duluthstreams.org is the focus of the project and offers water quality, biological, and GIS data in the context of a variety of school- and community-oriented educational material.
Fate and degradation of petroleum hydrocarbons in stormwater bioretention cells.
(2012-08) LeFevre, Gregory Hallett
This dissertation describes the investigation of the fate of hydrocarbons in stormwater bioretention areas and those mechanisms that affect hydrocarbon fate in such systems. Seventy-five samples from 58 bioretention areas were collected and analyzed to measure total petroleum hydrocarbon (TPH) residual and biodegradation functional genes. TPH residual in bioretention areas was greater than background sites but low overall (<3 µg/kg), and well below either the TPH concentration of concern or the expected concentration, assuming no losses. Bioretention areas with deep-root vegetation contained significantly greater quantites of bacterial 16S rRNA genes and two functional genes involved in hydrocarbon biodegradation. Field soils were capable of mineralizing naphthalene, a polycyclic aromatic hydrocarbon (PAH) when incubated in the laboratory. In an additional laboratory investigation, a column study was initiated to comprehensively determine naphthalene fate in a simulated bioretention cell using a 14C-labeled tracer. Sorption to soil was the greatest sink of naphthalene in the columns, although biodegradation and vegetative uptake were also important loss mechanisms. Little leaching occurred following the first flush, and volatilization was insignificant. Significant enrichment of naphthalene degrading bacteria occurred over the course of the experiment as a result of naphthalene exposure. This was evident from enhanced naphthalene biodegradation kinetics (measured via batch tests), significant increases in naphthalene dioxygenase gene quantities, and a significant correlation observed between naphthalene residual and biodegradation functional genes. Vegetated columns outperformed the unplanted control column in terms of total naphthalene removal and biodegradation kinetics. As a result of these experiments, a final study focused on why planted systems outperform unplanted systems was conducted. Plant root exudates were harvested from hydroponic setups for three types of plants. Additionally, a solution of artificial root exudates (AREs) as prepared. Exudates were digested using soil bacteria to create metabolized exudates. Raw and metabolized exudates were characterized for dissolved organic carbon, specific UV absorbance, spectral slope, florescence index, excitation-emission matrices, and surface tension. Significant differences on character were observed between the harvested exudates and the AREs, as well as between the raw and metabolized exudates. Naphthalene desorption from an aged soil was enhanced in the presence of raw exudates. The surface tension in samples containing raw harvested exudates was reduced compared to samples containing the metabolized exudates. Plant root exudates may therefore facilitate phytoremediation by enhancing contaminant desorption and improving bioavailability. Overall, this resarch concludes that heavily planted bioretention systems are a sustainable solution to mitigating stormwater hydrocarbon pollution as a result of likely enhanced contaminant desorption, and improved biodegradation and plant uptake in such systems.
Field-scale evaluation of MN-sourced biochar for comprehensive contaminant removal from parking lot runoff
(2023-03) Weelborg, Karina
The performance of catchment-scale filters containing sand and red-pine biochar, produced at 550oC, were monitored for 2 years. Six events from the 2022 field season showed relative flow equalization between the sand and biochar filters and were used for detailed performance analysis. Both filters provided removal of E. coli, total phosphorus, metals, total organic carbon, and total suspended solids. The sand and biochar filters provided inconsistent removal of orthophosphate. Both filters exported nitrate, though the biochar filter to a lesser degree. The addition of biochar provided greater concentration decreases for zinc and total suspended solids though no statistically significant difference between the sand and biochar was found for any filter performance. Results from this study highlight the importance of adjusting biochar production conditions for development of characteristics needed for contaminant removal and the importance of validating laboratory results in the field.
Fifteen Year Evolution in Implementing Policy through Education and Marketing: A Case Study of a Water District Mandated Stormwater and Sanitary Flow Separation Program
(2010) Zwiebel, Zandra A
This investigation sought to use descriptive case study methodology to empirically evaluate how the educational methods and approach related to a policy mandated program have evolved over a 15 year period. The program of interest was implemented to facilitate compliance with a water district mandated reduction in stormwater entering the sanitary sewer system, reduce overflows that violate the Federal Clean Water Act (CWA).Comparative analysis was conducted on 21 examples of program materials developed for public outreach and education, using recent theoretical and empirical models of pro-environmental behavior (PEB). An included literature review, conducted to provide external validity to the research, summarizes the evolution of a 40-year history of environmental education (EE) models and theory. Initiated with passage in 1970 of both the National Environmental Policy Act (NEPA) and the first National Environmental Education Act (NEEA), EE models and theory have changed significantly in four decades. This study chose one relatively new theoretical model (the Reasonable Person Model) and one recent empirical meta-analysis model (MASEM) to identify demonstrated variables in PEB response. The variables of each model were then operationalized in order to allow for a comparative analysis with the 21 specific EE program examples. Data analysis indicated that the program examples, as they evolved over time, consistently addressed a greater diversity of the operational variables identified, and in noticeably more instances. This supported the study’s original proposition, predicting that the products of a successful EE program, refined over time to address audience motivation and information need related to specific PEBs would correspond with the PEB models chosen for the study.
Green Stormwater Infrastructure Code Audits: Updating Local Regulatory Structures for a Changing Climate
(2024-03) Carlson, Jessy R; Hinds, Juli Beth; Rodman, Madison G; Sprague, Tiffany A
The impacts of climate change, such as increasingly intense storms and more frequent floods, mean regulatory frameworks designed to manage stormwater runoff in previous decades may no longer be effective; codes and ordinances may inadvertently prohibit or inhibit the use of nature-based approaches to managing stormwater runoff. To adapt to current and projected climate change scenarios, local governments need updated regulatory frameworks that effectively manage stormwater runoff in a changed climate. Adapting local regulations to promote systematic use of green stormwater infrastructure (GSI) and other nature-based solutions is a key strategy that can contribute to the development of resilient, climate-adapted communities. We worked with ten urban and rural municipalities across the Duluth area to conduct code audits and assist with designing and accomplishing community-specific GSI objectives, and we are currently expanding this project to include Lake and Cook Counties. These participating communities display a diverse array of geographical and demographic characteristics. However, after working with these communities’ technical staff and elected representatives to assess their regulatory structures and internal policies for areas that could be updated to prepare for increased heavy precipitation events, we have noted some important themes regarding needs, challenges, and opportunities that cut across the region. This poster will share what we are hearing from these communities and whether these themes point to emerging climate adaptation needs in Northeast Minnesota.
Hydrodynamic separator sediment washout testing.
(2010-07) Saddoris, David Allan
Hydrodynamic separators are widely used in urban areas for removal of suspended sediments and floatables from stormwater due to limited land availability for the installation of above ground stormwater best management practices (BMPs). Hydrodynamic separators are often sized based on relatively frequent storm events. However, during less frequent storm events, device design treatment rates are exceeded and previously captured sediments can be washed out of the devices. To study the potential for scour and washout of previously deposited sediments in the sumps of hydrodynamic separators under high flow conditions during infrequent storm events, sediment washout testing methods using mass balance were developed for both controlled field testing and laboratory testing. The developed testing methods were utilized to conduct sediment washout testing on three full scale hydrodynamic separators: 1) an Environment21 V2B1 Model 4, 2) a STC1200 Stormceptor and 3) a 6-ft Downstream Defender. All three devices were tested in the laboratory. The Environment21 V2B1 device was also tested in the field. In addition to full scale testing, two scale models were constructed and tested in the laboratory. Previous work by others on describing sediment washout in standard stormwater sumps was applied to data obtained from the sediment washout tests to develop sediment washout functions which incorporate non-dimensional parameters. Washout functions were developed for each of the devices tested in the laboratory and the field, as well as for a modified ecoStorm device previously tested by others. The washout functions that were developed can be incorporated, along with removal efficiency functions, into continuous urban runoff models to predict maintenance schedules for hydrodynamic separator devices.
Identifying the Impact and Efficacy of Watershed Management on an Urban Stream
(2020-02) Distel, JohnMichael
Restoration and management of water resources have become a common counter to the degradation of hydrologic ecosystem services, specifically from the effects of urbanization. This project used a long-term data set to see if changes in discharge and concentration-discharge relationships could be attributed to water resources management at the watershed scale and for specific streamside infrastructure. The stream at the focus of this inquiry is Minnehaha Creek. It flows through the west metropolitan Minneapolis, Minnesota area – located in the north-central region of the United States. Two data sets were used in this study: 1) mean daily discharge, collected by a United States Geological Survey (USGS) stream gauge from 2007 – 2018, and 2) flow and water chemistry data, collected by the Minnehaha Creek Watershed District (MCWD) from 2009 – 2017. The water chemistry parameters used in the analysis include total phosphorus (TP), total nitrogen (TN), total suspended solids (TSS). Analysis showed an increase in discharge moving through the stream over time, likely due to increases in precipitation. Increasing minimum flows point to increasing shallow groundwater contributions and, therefore, increased infiltration across the watershed – a goal of the stormwater management within the Minnehaha Creek watershed. All C-Q relationships were negative and, corresponding to the discharge trends, concentrations decreased over time. However, flux of solutes remained steady. With increasing flows, a decrease in concentration with no change in flux is indicative of a reduction in sediment and solute transport – another goal of watershed management. No significant influence from the specific infrastructure analyzed in this study was observed. This is likely due to the data’s collection rate. Recommendations on improving data collection include adding temporal variety and ensuring representation of all levels of discharge. Recommendations are broken into three main categories: 1) assurance of representative sampling, 2) inclusion of temporal range in data collection and 3) broad distribution of sampling locations.
The Lakeside Stormwater Reduction Project (LSRP): Evaluating the Impacts of a Paired Watershed Experiment on Local Residents
(2011) Eckman, Karlyn; Brady, Valerie; Schomberg, Jesse
Scientists, city utilities staff, and local environmental engineers teamed up with homeowners to determine the best ways to reduce stormwater runoff from the Lakeside residential neighborhood in Duluth. The Lakeside Stormwater Reduction Project (LSRP) used a paired-watershed approach to assess the results of diverse stormwater treatments in the Lakeside neighborhood of Duluth on stormwater runoff into Amity Creek. The project investigated various installations that reduce runoff and can be easily maintained by homeowners. The goal was to identify effective methods to reduce runoff contributing to problems in Amity Creek and the Lester River. To complement extensive biophysical monitoring, a knowledge, attitudes and practices (KAP) study was done in April 2008. The purpose was to obtain baseline human dimensions data; assess residents’ willingness to participate in the project; and to identify possible barriers to adoption. Baseline information and residents’ views about stormwater issues were obtained in April 2008. The first-round KAP data was used to refine project design, and to identify possible barriers to participation. The study was repeated with the same sample in September 2010 to evaluate outcomes and impacts. Comparison of the pre and post KAP data shows a significant increase in respondent knowledge about stormwater, a positive shift in attitudes, and strong evidence of adoption of stormwater practices as a result of project efforts. The project successfully increased awareness among residents about the impacts of stormwater on Amity Creek and the Lester River, and fostered adoption of stormwater management practices by homeowners, even in the control sample.
Minnesota Stormwater Research Program Annual Report - 2024
(2024-07-18) Bilotta, John; Karschnia, Maggie; Wells, Elizabeth; Johnsen, Lenna
Annual report for the Minnesota Stormwater Research Program and the Minnesota Stormwater Research Council
Modeling hydrothermal inputs to cold-water streams in urban watersheds.
(2011-05) Janke, Benjamin David
This research investigated the impact of urban development on the temperature of cold-water streams, which are crucial to maintaining viable populations of biota that are unable to survive in warmer waters. Since the temperature of these streams is typically maintained by significant amounts of groundwater inflow and riparian shading, the land cover conversion associated with urban development - replacement of crops or natural land with buildings, roads, lawns, and parking lots - has a negative impact, as these land-use changes tend to increase the amount of impervious surface area and reduce the amount of natural shading provided by vegetation. As a result, surface runoff rates and temperatures from rainfall events are amplified, watershed infiltration is reduced, and stream temperature increases. A primary goal of the project was to produce a tool to assess the impact of proposed urban development on stream temperatures in a particular watershed. The research procedure focused primarily on understanding and developing models for the hydrologic and heat transfer processes within a watershed, with particular focus on rainfall-runoff. Specifically, two process-based models were developed: one for estimation of runoff flow and temperature from urban surfaces, and a second for estimation of groundwater input to a stream from observations of water quality. The runoff temperature model demonstrated that heat export by rainfall-runoff from a paved surface is determined by antecedent pavement temperature and rainfall intensity/duration, and that stream-wise gradients in runoff temperature are negligible. The model contributed to the development of a more comprehensive stormwater modeling tool (MINUHET) by justifying the simpler solution technique used by MINUHET's runoff model. MINUHET was shown to accurately simulate runoff flow rate and temperature at the outlet of a small urban watershed, particularly when hydrologic data is available for calibration. The roof surface temperature analysis provided evidence that the contribution of heat from rooftops is negligible relative to that of paved surfaces. Lastly, the use of temperature as a groundwater tracer was shown to be an effective and inexpensive method for determining groundwater input to a stream, provided that the limitations of the approach are borne in mind when applying the method.

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