In the late 1980s and early 1990s, Barr and the U.S. Army Corps of Engineers implemented a $40-million stormwater management plan for the BCWMC and the City of Minneapolis as the local sponsor. The plan included replacing the two-mile conduit to the Mississippi River with a combination of a double-box culvert and bedrock tunnel. This tunnel system provides conveyance and flood control for Bassett Creek and drainage for portions of Interstate Highways 394 and 94. This was in addition to implementation of several flood control project features along Basset Creek, including control structures, crossings, channel improvements, a fish barrier dam, and culverts.

Since construction, Barr has provided periodic inspections and designed repairs of the flood control project features and tunnel system for the BCWMC and the City of Minneapolis. The tunnel inspections consist of evaluating the tunnel for cracking, settlement, seepage, infiltration, concrete deficiencies, exposed rebar, and foundation issues. For example, Barr inspected the 6,100-foot bedrock tunnel in 2020 and the entire 5,600-foot double-box culvert section (cut and cover tunnel) most recently in 2024. Barr prepared a feasibility study for the double-box culvert repairs in 2025 and, if approved, will assist the BCWMC with implementing recommended repairs in 2026/2027.

Barr developed a natural-resources management plan for Thompson County Park in Dakota County, Minnesota. We conducted a natural resources inventory to assess the park’s native plant communities and wildlife habitat as well as the water quality of Thompson Lake. We also documented tree diseases and invasive species. After mapping existing plant communities within the park and ranking their ecological quality, we used that information to develop a plan for restoring native plant communities and managing the park’s water, soil, and wildlife resources.

The final plan provides an overall strategy for managing the park’s natural lands, including phased native-plant-community implementation, invasive-species control, and lake-water-quality improvement as well as monitoring recommendations, cost estimates, and funding sources. The document is used by park managers and the county’s planning commission to prioritize and budget for activities, and it can be used by the public to understand and preserve the park’s natural resources.

After reviewing the in-line inspection data for features of concern, a client noticed a potential integrity issue with a pipeline under an interstate highway. Based on the location of the feature, the client decided to accelerate a replacement project.

Although an open-cut repair was explored, limited access and the possibility of impacting transportation infrastructure made horizontal directional drilling (HDD) the most viable option. 

The client selected Barr as its prime consultant to create a detailed engineering design. Our work entailed a geotechnical review of the subsurface conditions, mechanical analysis of tie-in connections, and a detailed civil plan to facilitate construction setup. 

We conducted a geotechnical investigation with borings to evaluate conditions at the new pipeline’s proposed entry and exit points. Based on the results, we made geotechnical recommendations to J.D. Hair & Associates, our subconsultant and the HDD designer. Once the drilling profile was designed, Barr’s civil team developed the workspace layout, while our mechanical team supplied isometric drawings, hydrotest parameters, and a bill of materials. We remained on site during drilling to assist with construction concerns.

A spillway capacity study revealed that the Bond Falls reservoir, constructed in the 1930s, had insufficient capacity to pass probable maximum flood (PMF) flows. The reservoir was drawn down to lower the risk of flooding in event the dam’s PMF level was exceeded during a storm. To meet Federal Energy Regulatory Commission (FERC) dam safety criteria, the dam needed a new spillway sized to pass a PMF event.

Barr developed a detailed design based on a physical scale-model study configuration tested by St. Anthony Falls Laboratory. The design consisted of two new gates, wider and higher than the original single gate. A new minimum flow pipe was also designed integral with the new concrete spillway structure to provide minimum discharge flows to the downstream river channel.

Our design included a staged cofferdam to minimize reservoir drawdown and provide a dry, stable work area for demolition and construction activities. Barr developed a water management strategy to stage the cofferdam sequencing to accommodate construction and maintain continuous minimum flows to the downstream river channel throughout construction.

The new spillway consists of the following features:

Barr’s work also included documenting a mini–potential-failure-mode analysis (PFMA) conducted to identify potential failure modes, fatal flaws, and critical design issues to be addressed during development of a final design. The mini-PFMA served to supplement a previous PFMA, adding failure modes applicable during construction of the replacement spillway.

The completed Bond Falls spillway can now accommodate twice as much discharge as the preconstruction configuration. Barr also developed a commissioning and refill plan to foster safe, controlled startup and fill conditions.

For nearly two decades, Barr has helped the city of New Brighton with the New Brighton Exchange, one of the most ambitious and complex brownfields projects in Minnesota. A former dump, known as Old Miller Dump, occupied about half of the eastern portion of the site. Barr worked with the city on a highly complex design and construction effort that addressed environmental concerns presented by the dump. 

In the 1960s, one million cubic yards of debris were placed in a pond and swamp at Old Miller Dump. Barr designed and oversaw excavation of 20 percent of the dump with on-site consolidation and capping of the remainder of it, along with a passive landfill-gas-collection system. The landfill cap and gas-collection system is being periodically monitored by Barr to verify that high levels of methane in the capped dump materials are being dissipated safely without uncontrolled migration to nearby buildings, which were constructed following the dump closure.

The cleanup of the New Brighton Exchange site has been completed, and most of the area is now redeveloped, including five corporate headquarters and a new 25-acre residential development.

The century-old Island Lake Dam not only regulates water levels and supports recreation on the Island Lake Reservoir, but also supports generating power for Minnesota’s largest hydropower system. When Minnesota Power identified a critical problem—five leaking sluice gates causing a reduction in power generation and posing operational, environmental, and safety risks—it turned to Barr for assistance.

Designing and implementing dam repairs called for special precision. The gates’ location, 50 feet below the water’s surface meant divers couldn’t safely access the gates for repairs. An additional complication was that the dam’s original design called for partial drainage of the reservoir to access the gates, and this option was no longer feasible.

Barr performed an options study for a replacement design that would improve gate integrity and reliability. Once a design was selected, close collaboration among Minnesota Power, Barr, and construction contractor J.F. Brennan Company, Inc., along with the use of a three-dimensional model, enabled development of a final design and detailed construction plans.

The design configuration extended the end walls and piers vertically by 30 feet. New bracing and framing were added to distribute loads. Bulkhead slots accommodated steel bulkheads for dewatering. Finite-element models were used to assess load stresses and size new elements to help assure structural integrity and stability. As gate design was developed, Barr also conducted a potential failure mode analysis (PFMA) to help assess the risks associated with the design’s construction, operation, and long-term maintenance.

This repair and restoration project received a 2021 Grand Award in Engineering Excellence from the American Council of Engineering Companies of Minnesota.

Normandale Lake is a shallow, 100-acre lake located along Nine Mile Creek in Bloomington, Minnesota. The lake is an important amenity within Normandale Lake Park, which includes a popular trail around the lake and an amphitheater. Poor water quality, frequent algal blooms, and an abundance of invasive curly-leaf pondweed and other aquatic plants in Normandale Lake prompted strong public support for improvements. A 2017 study conducted by Barr for the Nine Mile Creek Watershed District (NMCWD) concluded that internal phosphorus loading and the presence of dense aquatic vegetation, specifically curly-leaf pondweed, were degrading water quality and the health of the aquatic communities. A 2018 fishery survey identified a large population of carp, a bottom-feeding fish that stirs up lake bottom sediments and contributes to poor water clarity. To fix the problems, the NMCWD has embarked on a holistic lake management program that includes drawing down the water to freeze the lake bottom sediments and kill invasive curly-leaf pondweed, treating with alum to prevent the internal release of phosphorus from lake bottom sediments, and tracking carp movement for future management.

In late-summer of 2018, the NMCWD began drawing down the lake by pumping and installing a permanent bypass pipe. With Nine Mile Creek flowing through the lake, the full drawdown of water levels posed a significant challenge. The lake was fully drawn down by early-November, and by mid-February 2019 the top 15-24 inches of lake sediment were frozen. The effectiveness of the drawdown in reducing curly-leaf pondweed will be assessed throughout the summer of 2019; preliminary results indicate a significant decrease in the presence of curly-leaf pondweed throughout the lake. The NMCWD also conducted an alum treatment in spring 2019 to prevent internal loading from phosphorus in the lake bottom sediments. The DNR restocked the lake with fish in the spring of 2019 in hopes of re-establishing the population of predator fish, and our client conducted a fishery population survey and carp tracking.

Great River Energy’s Coal Creek Station is a two-unit, 1100-MW, coal-fired power plant in North Dakota. Over the past several years, the plant has undergone many changes that needed to be incorporated into an arc-flash model to determine the incident energy and hazard level for appropriate PPE.

To develop an updated arc-flash model, reduce facility personnel’s risk of exposure to electric energy, and comply with electrical safety requirements for employees (NFPA 70E) and industry standards (IEEE 1584-2018), Barr conducted a power system analysis.

Barr built a new model based on existing drawings, old model data, and other existing information. We verified that field protective-device settings were accurate, added a DC battery system to the model and panelboards with over 2000A fault current, completed a short-circuit analysis, and summarized our findings and mitigation recommendations.

Barr’s analysis satisfied the requirements of NFPA 70E, renewed confidence in the model’s accuracy and settings, enables field personal to wear appropriate arc-flash PPE, and identified areas of high incident energy for future mitigation.

Barr was commissioned by a confidential client to conduct an independent dam safety review (DSR) of a very large tailings-storage facility (TSF) in Mexico. This external TSF, built using centerline construction, is classified as an extreme consequence facility based on the highest potential consequence and/or the failure scenario that would result in the worst consequences, which requires a DSR be completed every five years. The DSR was conducted in general accordance with standard practices and regulatory requirements.

Barr’s DSR consisted of reviews of documents (dam design, slope stability, seismic, shear strength, hydrotechnical and freeboard, risk control); construction (foundation and embankment materials, tailings materials); operations, maintenance, and surveillance (instrumentation and monitoring, manual); and safety management and emergency preparedness, public safety, and security. The DSR also included site inspection and staff interviews (governance, consequence classification, design assessment) and a dam safety report (analysis and findings of deficiencies, non-conformances, and recommendations).

Among the primary topics addressed were shear strength characterization of the tailings and foundation soils, deformation of the dam, instrumentation thresholds, and static liquefaction, in addition to operational and governance topics.

In response to failing, unattractive landscaping at many of its facilities, Hennepin County wanted to learn about the types of plants that would thrive at county sites—many of which receive minimal maintenance—and which plants to avoid. Barr facilitated a series of workshops for three county departments to understand the landscaping problems better and to discuss sustainable solutions.

Using feedback from the meetings, we developed sustainable landscape guidelines for efficient, hardy, and attractive landscapes. The guidelines address site and plant selection, soils, water, health and well-being, materials selection, landscape implementation and maintenance, and education.

Barr also generated a series of plant lists to guide landscaping at Hennepin County facilities, including:

The guidelines and plant lists help Hennepin County navigate new landscape projects and prioritize landscape management, resulting in more durable, robust landscapes.