Drainage systems in downtown Minneapolis were experiencing capacity problems, so the City of Minneapolis hired Barr to develop an XP-SWMM model of the Central City, Chicago Avenue, and 11th Avenue drainage systems and perform a feasibility study of the Central City tunnel system.

First, Barr developed a detailed model of each of the tunnel systems. Then, the model of the Central City tunnel system was used to conduct a feasibility study to investigate its hydraulic capacity and identify alternatives to mitigate its existing capacity problems. We provided the city with a recommended alternative for addressing the existing capacity issues. The City completed construction of the project in 2024.

Whitewater State Park, located in Winona County, is known for its scenic limestone bluffs, deep ravines, and spring-fed Whitewater River. The middle branch of the Whitewater River flows through the park and is spanned by several highway, road, and foot bridges. An extreme storm in 2007 severely damaged the river channel downstream of the Highway 74 bridge. In 2016, the DNR undertook a comprehensive channel restoration using natural channel design principles, seeking to realign the river to emulate an existing stable reference reach upstream of the project area.

Working closely with the DNR, Barr developed a design recommendation report, final design drawings, technical specifications, and cost estimate to reconfigure a 1,700-foot channel reach. Hydraulic modeling was conducted using both one- and two-dimensional models to evaluate fish passage, stabilization measures, and upstream project impacts. Barr used natural channel design, fluvial geomorphology, and general engineering principles to develop the primary design elements, including reconfiguring the upstream segment of the project reach, constructing elliptical rock riffles, reconstructing a damaged boulder weir downstream of the highway bridge, installing boulder clusters to provide habitat, and lowering an overbank area to provide floodplain connectivity. Riverbanks were stabilized using toe wood and native vegetation that can thrive in the site’s difficult growing conditions. The design, developed in close collaboration with the Minnesota Pollution Control Agency, included detailed erosion-control sequencing.

Construction is being carefully timed to respect trout spawning periods when in-channel work is restricted, while not leaving the channel in a vulnerable condition for extended periods of time.

Barr prepared an initial Title V permit application for a confidential client’s assets associated with a nearby Salt Lake City refinery. Although the client had originally applied for a Title V permit in 1996, the Utah Division of Air Quality hadn’t issued the permit, and a lawsuit against the agency resulted in a requirement for the client to submit an updated version of the application. Our work included:

1. Conducting a comprehensive regulatory-applicability analysis of federal and state requirements, including those under Utah’s state implementation plans for PM₁₀ and PM_2.5

2. Identifying emission sources, applicable regulations, and individual requirements for each emission source

3. Preparing a narrative describing operations and preparing an associated block-flow diagram

4. Calculating the facility’s PTE (potential to emit)

5. Compiling a list of compliance monitoring devices and a description of applicable test methods

6. Assisting with application submittal, discussions and negotiations with UDAQ, and review of the draft Title V permit prepared by the agency

Following review by the general public, UDAQ, and U.S. EPA, the Title V permit was issued to the client.

Since 1978, Barr has provided complete CERCLA-related services to Joslyn Manufacturing Company at its former wood-treating facility in Brooklyn Center, Minnesota. This 30-acre site was used to treat utility poles with creosote and pentachlorophenol and was ranked 44 on the EPA’s National Priority List. Barr completed extensive investigations and feasibility studies at the site; sampled surface soils, sediments, vapor, groundwater, and surface water; conducted a human-health risk assessment; and completed several remedial actions. Soil remediation has been completed using an onsite land treatment unit, and the majority of the site has been redeveloped for light industrial use. Remediation of wetland soils on the site’s lakeside is currently being planned.

To address groundwater contamination, Barr designed, implemented, and has since operated a groundwater pumpout system and recovered dense nonaqueous-phase liquids (DNAPL). The system has significantly reduced the extent of the groundwater contamination so that it no longer extends off-site and has successfully prevented contamination from migrating to the lower aquifer or to nearby surface water bodies. Since operations began, we have recovered more than 17,500 gallons of DNAPL and removed over 85 tons of wood treating chemicals. Through regular system maintenance, monitoring, groundwater modeling, and routine checks, we have reduced the pumping network and volume, resulting in operations and maintenance cost savings while preserving system effectiveness.

At its coal mine near Underwood, North Dakota, Falkirk Mining noticed unusual vibrations occurring in its silo during certain periods. Concerned about the silo’s structural stability, the company asked Barr to investigate the cause. 

Our structural engineers installed four vibration and displacement sensors at various heights on the silo to record data multiple times a second. Barr’s cloud-based data-warehousing system processed the high-frequency instrumentation data into hourly and daily averages for analysis. We then used statistical fingerprinting techniques to identify the specific characteristics of the vibrations when they occurred, and with the client’s assistance, identified previous dates on which those types of vibrations had taken place.

The real-time instrumentation data showed that the silos were swaying slightly and vibrating at a frequency centered on 1.25 Hz. Barr theorized that differences in the coal level in the silo were affecting the mass distribution and creating the vibrations, and conducted a dynamic structural analysis to test that theory. We used the results to (1) demonstrate that the vibrations were not caused by activities linked to specific days of the week or external loading conditions, and (2) help Falkirk Mining evaluate several hypotheses about the circumstances causing the vibration.

Our analysis of the vibrations and their inferred stresses indicated that the vibrations were likely the result of non-uniform vertical flow patterns in the coal mass inside the silo, and did not threaten the structure’s stability.

In the spring of 2019, a rock-fall event—with large boulders falling from the scenic rock bluff into a pedestrian area—occurred at Interstate State Park in Taylors Falls, Minnesota. The Minnesota Department of Natural Resources (DNR) hired Barr for a two-phase project to provide for short-term and long-term safety of visitors to the park in the project area.

In the first phase, Barr produced plans and specifications to remove and stabilize boulders and cobbles on the scenic bluff face to provide short-term public safety. This work included developing plans and specifications for rock scaling and bolting that would allow the installed bolts to be hidden from view to meet requirements of the Natural Scenic Riverway.

In the second phase, Barr worked with the DNR to design a rock-fall barrier that met the State Historic Preservation Office’s requirements to not affect the look and feel of historical elements in the area. Our design included an impact barrier that is faced with rock removed from the first phase. Services included producing topography of the bluff from data collected from a drone flight, producing high-quality renderings of the rock-fall barrier, rock-fall analysis, impact design of the concrete barrier, structural design of the barrier, part-time construction observation, and development of construction contract documents. 

Fountain Lake is a major aquatic resource for the City of Albert Lea and the surrounding region. However, a significant sediment load into the lake caused sedimentation and nutrient deposition—leading to poor water quality, reduced lake use, and fish kills. The SRRWD retained Barr to conduct a preliminary engineering analysis of lake dredging. The study included an in-depth analysis of water quality to document anticipated changes and improvements resulting from dredging. Sediment-sampling and water-quality-monitoring data helped calibrate a three-dimensional, hydrodynamic sediment-transport and water-quality model (Delft3D), which was used to evaluate and understand lake-water-quality management options.

As part of the study, Barr developed dredge prisms (sediment removal plans) based on phosphorus content. We also evaluated sediment dewatering, dredged-material disposal and reuse options, and the likely effects of dredging on lake water quality. Modeling results indicated that the internal bed load was a significant source of phosphorus—up to 81 percent of the lake’s growing-season total phosphorus budget. Therefore, sediment dredging was identified as the primary management tool for improving the lake’s water quality and habitat, enhancing fisheries, and increasing public use.

Coordination with multiple municipal, county, regional, state, and federal stakeholders was a key component of Barr’s work. The district completed final design and permitting and began hydraulically dredging Fountain Lake in 2018. Barr also helped the district obtain grant funding and assisted with environmental review and permitting.

The critical issue facing the Des Moines Water Works since the initial design of the Maffitt Reservoir Well-Field on the Raccoon River is the limited saturated thickness of the underlying alluvial aquifer. The key to productivity of the well field is inducing infiltration from the Raccoon River. Barr first conducted a pre-design study to understand the hydrogeologic environment of the alluvial aquifer.

Using existing and new data and transient simulations of the aquifer tests, we then designed and calibrated a regional groundwater flow model with two highly discretized, linked local models. The local models were required for evaluating the design of new radial collector wells. We also performed a predictive uncertainty analysis of the productivity of the expanded well field. Barr then used the groundwater flow models from calibration and the predictive analysis to design two new radial collector wells and estimate the expanded well field capacity under a number of scenarios. The estimates indicated that the client would likely not be able to produce the desired amount from the expanded well field under all conditions, so they are now focusing on other sources of supply.

Over the past several decades, I-35W at 42nd Street, a major interstate artery in Minneapolis, has experienced flooding during intense storm events. Additional stormwater storage requirements prompted the Minnesota Department of Transportation (MnDOT) to hire Barr to develop flood-risk-reduction concepts. Complex hydraulic modeling, the need to understand ground conditions, and a restricted surface workspace posed challenges. The limited footprint and high groundwater conditions meant that the solution might require deep structures, such as tunnels and/or shaft-type construction. Barr provided geotechnical data of the underlying soil and bedrock conditions; accurate hydraulic modeling; and constructible concepts that not only met the hydraulic objective but also considered the challenging geologic conditions. 

Barr led a multi-partnered team in final design of a 14-acre-foot stormwater storage facility to reduce highway flooding with the goals of maintaining a 100-year design life, minimizing life-cycle costs, reducing groundwater infiltration into the facility, and optimizing long-term maintenance. We completed hydraulic and structural design, including design of a weir structure to convey flow into the stormwater storage facility, connections between cells, and evaluation of impacts on water levels. We also developed a geotechnical monitoring program to provide baseline and construction monitoring for the duration of the project. Construction was substantially completed in November 2023.

By the mid-2010s, growth and development were beginning to strain, and would soon surpass, the capacity of Blaine’s water treatment infrastructure. The city experienced two water outages over a five-week span in 2017, forcing school closures, triggering water-boiling advisories, and eroding residents’ confidence in the city’s water supply. In response, city leaders prioritized water system improvements and construction of Water Treatment Plant 4 (WTP4), a higher-capacity facility that would treat groundwater from four new well fields supplying the public potable water system.

The city hired Barr Engineering Co. to provide concept development, piloting, design, bidding, and construction services for WTP4. Expediting the project timeline to address the ongoing threat of water outages, Barr partnered with Bolton & Menk to design a facility that can treat 6,000 gallons per minute, employs leading-edge sustainability practices, and restores public trust in the city’s water supply.

WTP4, which became operational in the summer of 2021, includes aeration, iron and manganese dual media gravity filtration, chemical feed, lamella plate settler for backwash recovery, and high-service pumping. The facility also maximizes water efficiency with additional considerations toward environmentally conscious and sustainable facility and site design. Stakeholder input helped inform a design that promoted a host of sustainability features, including maximum backwash water reuse (99% recovery) with a lamella clarifier; energy-efficient lighting and pumping; green roofs; rooftop solar energy panels; reuse of rooftop rainwater; and green infrastructure.

The facility has restored safe, reliable water supply to one of Minnesota’s fastest-growing cities. Working within the North and East Metro Groundwater Management Area, Blaine WTP4 gives additional attention to groundwater health, environmentally friendly water management practices, and sustainable design. Doubling the city’s water treatment capacity, this plant was completed with a community focus and is positioned to provide the City of Blaine safe and reliable drinking water into the foreseeable future.