Runoff

This research summary is part of the final deliverable for Report 2024-23, "Re-Use Of Minnesota Waste Material In Sustainably Designed Soils: Part 2, published in September 2024

Minerals, forestry, agriculture, and industrial activities in Minnesota 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, as well as tested engineered soil mixes for roadway applications, 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 (LCA) 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.

This is the appendix to Report 2024-09, "Stormwater BMP Inspection and Maintenance Resource Guide."

This Research Summary is part of the final deliverable for report 2024-09, published in June 2024.

The use of salt brine has proved successful as an anti-icing and de-icing agent. Consequently, many salt brine production systems have been installed in Mn/DOT facilities throughout the state. Several different approaches have been attempted in designing these systems. Experience has identified problems associated with some of these designs. One of the objectives of this document is to establish a recommended procedure for installing and operating salt brine systems, based on these experiences. The second objective of this document is to stress how important it is to store and handle salt/ salt brine and truck wash water properly. Salt has the capacity to adversely impact soils/ vegetation, surface water and groundwater at sites where salt runoff is not controlled. Every attempt must be made to prevent accidental production of salt brine through truck washing or from salt/winter sand stockpile runoff. Currently, the MPCA does not have rules specifically regulating salt or salt brine storage. However, mishandling of these materials could result in strict rules being adopted. Therefore, it is in Mn/DOT'S best interest to use these materials responsibly.

In response to the lack of specific standards and knowledge regarding salt brine pollution, the Maintenance Standards Section, under the direction of W. F. Murphy, Maintenance Standards Engineer, was called upon to make a study of Minnesota Highway Department stockpile sites and pollution abatement facilities in an effort to determine what direction and course of action the Department should take. This report summarizes the results of this study. An update to this report was published in 1989.

An extensive library research program was carried out in 1978 to determine what publications are available that deal with water pollution from highways and urban areas. The literature search indicated that considerable research is being done in this area of study. A number of publications were located which should be helpful in determining how accurate the present method of estimating water pollution from highways is. There was an attempt to limit the researcher to articles published after 1970. Although the bibliography is extensive, it is not exhaustive. The original report was published in 1978. Since that time, an additional 114 articles have been reviewed to determine which ones related to the subject study. The supplemental bibliography is published in two sections. Part 1 is a list of publications alphabetized by the author, with appropriate annotations. Part 2 is a list of all publications perused as a part of the research. Part 2 contains articles listed in Part 1.

This study was undertaken to characterize the physical and chemical characteristics of runoff from an urban highway segment in the Minneapolis - St. Paul metropolitan area. We strove to find out if highway runoff was, and if so to what degree, a potential source of water pollution. Concentrations of pollutants had to be looked at in relation to such things as rainfall amounts, flow rates, time of year, event type and dry days. This study and report is the first in a series and will be followed by several others from other sites in the area. These sites will be of differing characteristics in highway geometries, design, traffic, etc. From this approach, a more thorough understanding of highway runoff should result.

Stormwater treatment practices, often referred to as stormwater best management practices (BMPs), require a substantial commitment to maintenance, including regular inspections and assessments. Existing regulations require governmental units to develop a systematic approach for ongoing inspection and maintenance to ensure that they are achieving their desired treatment goals. A lack of maintenance will lead to a decrease in BMP performance and will often result in expensive rehabilitation or rebuild. In 2009, SRF Consulting produced a maintenance guide for the Local Road Research Board (LRRB) (Marti, et al. 2009). In 2023, the LRRB commissioned the University of Minnesota St. Anthony Falls Laboratory to update this guide to reflect new best practices. The Stormwater BMP Inspection and Maintenance Resource Guide (the Guide) is a supplement to the Minnesota Stormwater Manual (MPCA 2023) and will help the reader plan for recommended long-term maintenance activities through guidance on visual inspection, testing, and monitoring methods for identifying what maintenance is needed, and when it is needed. The Guide describes inspection and maintenance for constructed stormwater ponds (both dry and wet) and wetlands, underground sedimentation practices, infiltration practices, filtration practices, bioretention practices, permeable pavements, and stormwater harvesting. In addition, the Guide includes a section on Meeting Stormwater Management Objectives, which provides information on achieving reductions for sediment, phosphorus, nitrogen, metals, chloride, pathogens, and organic chemicals. The Guide also includes Field Inspections Resources, which contains inspection checklists and maintenance activity recommendations for all of the practices listed

Storm-water runoff from the Woodbridge neighborhood of the City of Shoreview had previously been managed through culverts and other hydraulic structures. In adherence to the Clean Water Act, many watersheds instituted limits to the percentage of storm water that may be allowed into certain lakes and rivers. To minimize this run-off and the associated impacts and in accordance with the City’s sustainable design policy, the City of Shoreview built the Woodbridge neighborhood local roads using pervious concrete pavements in 2008. Pervious concrete pavements exhibit high hydraulic conductivity and high sound absorption coefficient in local or low volume roads. They also provide cost savings through the minimization of hydraulic structures.