Working with the Hennepin County Regional Railroad Authority, Barr developed a risk-based program to help HCRRA manage its stormwater infrastructure and evaluate the likelihood of stormwater infrastructure failure and the possible consequences of failure. The risk assessment used spatial data of HCRRA’s stormwater infrastructure and other parameters related to topography, hydrology, soils, and other county and public infrastructure (such as roads, trails, railroads, and structures) as well as stormwater infrastructure condition assessment and inspection data.

Barr developed a methodology that ranks the relative consequence and likelihood of failure of all HCRRA’s stormwater infrastructure. A risk matrix was created using the results of those rankings to help identify and prioritize recommended actions related to ongoing inspection, maintenance, and replacement of HCRRA’s stormwater infrastructure. In addition to providing inspection frequency recommendations for each risk-based category, Barr also identified potential municipal, watershed district, and watershed management organization partners and developed planning-level cost estimates to remove and replace failing infrastructure. We also conducted a screening-level evaluation of water-quality improvement opportunities in relation to future culvert maintenance or replacement efforts and developed high-level cost estimates to remove, repair, and replace failing infrastructure.

District Energy St. Paul operates North America’s largest hot-water district-heating system fueled by biomass. The U.S. Department of Energy awarded the company a grant to study the potential for developing new district-energy systems in Minneapolis and St. Paul. Of particular interest was the area along University Avenue known as the Central Corridor, which follows the Green Line light-rail system between the downtowns of Minneapolis and St. Paul.

District Energy hired Barr to help assess the opportunities for developing energy districts within high-density areas of the metropolitan core. Barr provided GIS support and energy-use estimations for various areas within the 90-square-mile study. Combining a spatial-statistics algorithm with GIS mapping software enabled the generation of maps showing the areas of highest energy use. A ranking system for each cluster factored in total energy use, energy density per acre, potential for future growth, and other information, which in turn allowed District Energy to isolate clusters (“energy islands”) that held the most potential for contributing to a new energy district: those with clusters of heavy energy consumers and facilities with potential for waste-heat recovery.

District Energy used the information collected to assess the potential for increasing the energy efficiency of identified facilities, as well as for converting the systems of some facilities from burning fossil fuels to using renewable sources. Analysis of the study’s results allowed our client to create a blueprint for developing potential district-energy systems along the Central Corridor.

Northern Industrial Sands, (a subsidiary of Northern Capital Partners, LLC) hired Barr to conduct a resource assessment and obtain a reclamation permit to mine on a greenfield site. The resource assessment included drilling and sampling to determine the quantity and quality of sand available as well as the volume of overburden needed to be removed to economically mine the deposit. Barr used the software Vulcan to demonstrate the quantity and mine phasing that would recover the silica sand most efficiently. Concurrently, Barr collected the physical, biological, hydrological, and land-use data required for the reclamation permit after a public hearing attended by Barr staff representing the client.

After the resource assessment, Barr helped the client develop a set of engineering documents that were sent out for bids to build the plant facilities and devise a strategy to secure an air permit to build and operate a separate dry plant at an off-site facility.

Barr prepared and submitted an application for the construction waiver, which was granted, and, after verifying that the facility’s annual production goal of 1.8 million tons of dry sand would keep it under the major-source threshold, we also prepared and submitted an application for a synthetic minor-source operating permit, which was also granted. Our engineers and scientists also supported the client while it negotiated permit conditions with the state regulatory agency and responded to questions during the public-notice meeting.

The Wissota Hydro Generating Station serves as the control center for a majority of Xcel Energy’s Wisconsin hydroelectric facilities. It is the second largest in Xcel’s fleet in the state and retains the 6,200-acre Lake Wissota, a popular public recreational area. However, the facility was constructed before 1920, and, because of its age and overall importance to its operations, Xcel commissioned Barr to complete an alternatives evaluation report for rehabilitating the concrete spillway and powerhouse along with the Stauwerke spillway gates (which operate when higher headwater conditions occur). The intent of the evaluation was to identify projects that would sustain Wissota operations, along with the estimated costs for each.

Barr developed finite element analysis (FEA) models using RISA-3D software for the spillway, powerhouse, and Stauwerke gates. Based on a preliminary group of options and the FEA model results, we developed six spillway and two powerhouse modification options, including concept-level drawings and cost estimates, for Xcel’s further consideration.

A release of aqueous film-forming foam (AFFF), water, and petroleum products occurred during a fire at a refinery in the Midwestern U.S. The combined fluids migrated from the facility through stormwater features with eventual discharge to adjacent properties. Barr was hired to evaluate conditions following response actions and navigate regulatory concerns surrounding per- and polyfluoroalkyl substances (PFAS). Barr’s evaluation also assessed alternatives for mitigating the future risk of release of AFFF.

Several conceptual alternatives were evaluated, including completing grading and curbing to provide containment, upgrading existing infrastructure to pump fluids to aboveground storage tanks during a fire, and constructing ponds to provide storage. Evaluation criteria included the prevention of off-site discharge, impacts to firefighters, constructability within the active facility, permitting and regulatory considerations, capital costs, and operations and maintenance. The conceptual alternatives evaluation allowed the refinery to make an informed decision on the best approach before proceeding with its capital expenditure.

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Conventional practice limits sand-cap placement to tailings that have already achieved trafficable strengths. Most fine tailings deposits in the oil sands industry will not achieve this strength until they have consolidated and dewatered for some time. Sand-cap or sand-layer placement using hydraulic delivery methods offers great potential as a cost-effective, technically feasible capping method for treated fine tailings of the oil sands industry. However, hydraulic placement is a novel technique for cap placement that requires study to determine the range of conditions where it is feasible.

As part of a collaborative project funded by the Institute for Oil Sands Innovation and Canada’s Oil Sands Innovation Alliance, Barr and Deltares evaluated the conditions needed to successfully place a cap on treated fine tailings deposits. The scope involved geomechanical numerical modelling (using FLAC 2D) of both subaerial and subaqueous hydraulic placement of sand and coke caps on a fine tailings deposit. Physical modelling of the subaerial sand capping was also conducted to help validate the modelling and develop important factors for scaling to commercial applications. The work is an important step in establishing a foundation for an engineering and design approach for sand cap placement.

The Nose Creek Watershed Partnership (NCWP) has embarked on an ambitious project to create a detailed watershed-scale model of Nose Creek and West Nose Creek (collectively the Nose Creek Watershed). The NCWP hired Barr to develop a watershed model and a graphical user interface (GUI) that would allow NCWP staff to independently run the model. The goal is a detailed hydrologic, hydraulic, and water quality model of the watershed that allows the organization to better understand current watershed conditions, predict future conditions based on development and growth, and weigh potential outcomes of management strategies across jurisdictions.

Barr first conducted a scoping study to identify the best models that could be applied in combination to achieve those goals. We evaluated 20 models based on accessibility for software support, user friendliness, data requirements and availability, and output format. From these results and input from project partners, we recommended four models: SWAT, PCSWMM, EFDC, and HEC-RAS.

We began by developing a detailed model combining SWAT and PCSWMM to simulate watershed hydrology and water quality. Barr developed a SWAT model of the watershed’s rural areas, and we partnered with Kerr Wood Leidal Associates Ltd. to develop a PCSWMM model of urban areas encompassing four municipalities. The combined models are designed to run continuously to simulate long-term watershed processes. The NCWP selected a stand-alone, event-based HEC-RAS model, also built by Barr, to simulate channel and floodplain hydraulics.

This project is ongoing. Future phases of the work will include conducting SWAT and PCSWMM model calibrations and sensitivity analyses, constructing and calibrating an EFDC model of in-channel water quality processes, constructing the GUI, and applying the model to assess the current state of the watershed and evaluate future conditions and management strategies.

When Canadian Natural assessed the viability of non-segregating tailings (NST) as their primary fine tailings management strategy for complying with Alberta’s oil sands tailings reclamation requirements, they turned to Barr and the Dutch firm Deltares to plan and implement a NST deposition study. Barr and Deltares developed a bench- and pilot-scale test program in close coordination with Canadian Natural to evaluate the degree to which NST slurries segregate into their component parts during deposition using different mixtures and deposition methods, with the goal of identifying which combination of slurry composition and deposition method produces the least segregated deposit. Barr and Deltares also designed the testing apparatus, which included a tremie-diffuser deposition system and a 25-meter-long instrumented flume, and supervised equipment commissioning and operation.

The study was completed in two parts: evaluation of sub-aqueous and sub-aerial NST deposition (Part 1) and evaluation of three subaerial NST deposition methods and evaluation of deposits flowing over a long beach (Part 2). Barr supervised preparation of the NST slurries for the test program from mine-supplied materials by thickening fine tailings and adding sand to produce mixtures with target compositions and physical properties. Data collected from instruments and physical samples during and after the tests were compiled and analyzed, including development of a model to predict the segregation behavior of NST slurries based on composition and flow dynamics. A comprehensive report was then completed, and the model developed during this project was presented at the Third International Oil Sands Tailings Conference in 2012.

Barr developed a living-streets plan for RWMWD as part of a larger effort to meet the district’s goals for reducing pollution flowing to lakes in the watershed district. “Living streets” is a term that addresses livability and environmental needs and describes a design approach for rebuilding streets. By considering the many beneficial uses that a public right-of-way may provide, Barr offered alternative, multi-modal street designs. The City of North Saint Paul embraced this design approach to build road networks that are safer for pedestrians and bicyclists, include rain-garden designs, incorporate an urban-forestry strategy, promote walkable communities, slow traffic, provide aesthetic value, and improve the quality of lakes and streams by reducing stormwater pollution.

Barr’s living-streets framework provides North Saint Paul with a set of tools to design street-reconstruction projects that will be implemented more efficiently and at lower long-term cost. The framework aims to reduce impervious surface, treat stormwater in the right-of-way, and provide for safe pedestrian and bike movement. Communities within RWMWD will use the living-streets templates and guidelines to direct the design and construction process and supplement standing practices related to street reconstruction.

A confidential pipeline client plans to install multiple solar power facilities “behind the meter” at over a dozen pump stations as part of their environmental, social, and governance (ESG) and sustainability commitments. Each facility is planned to produce no less than 5 megawatts (MW) of solar power to provide electricity for pipeline operations. Barr was hired to provide key environmental evaluations to support feasibility analyses for these sites in the upper Midwest and advance them to the next stage of development ahead of construction planned for 2024.

Barr began by conducting desktop reviews for the proposed sites to assist our client in solidifying site boundaries. We developed figures with publicly available information to document natural resources and land cover at each site. We conducted desktop reviews to identify potential impacts to waterways, wetlands, and threatened and endangered species. Additionally, we performed cultural resource literature reviews at each site to identify previously recorded archaeological sites, historic structures, and other relevant cultural resources. Barr also developed a site-specific baseline environmental schedule to keep the environmental reviews on track.

Next, Barr quickly and efficiently summarized the desktop review information in a critical issues analysis (CIA) document for each site. The CIAs summarized the baseline environmental conditions and informed the client of site risks and constraints. With this information in hand, we created a permit matrix to evaluate federal, state, and local permits required for each site.

Finally, Barr coordinated onsite wetland delineations and functional assessments, as well as archaeological resource surveys with tribal monitor oversight, to identify environmental/cultural considerations for permitting and regulatory requirements. This information was also used by the client to further refine project boundaries and minimize impacts to identified resources. Barr’s work will ultimately help our client construct these projects more efficiently and meet their ESG goals.