Why the Target Center Sports a Green Crown: Unveiling the Secrets of Its Rooftop Grass

The Target Center, home to the NBA’s Minnesota Timberwolves and the WNBA’s Minnesota Lynx, boasts a feature that sets it apart from many other indoor arenas: a green roof, essentially a layer of grass and vegetation covering its expansive top. This isn’t some quirky design whim, but rather a conscious and calculated decision driven by environmental sustainability, energy efficiency, and stormwater management. The green roof helps to reduce the urban heat island effect, improve air quality, and manage rainwater runoff, contributing to a greener and more sustainable downtown Minneapolis.

The Multifaceted Benefits of a Green Roof

The installation of the green roof on the Target Center wasn’t just about aesthetics; it was a strategic move rooted in practical benefits:

• Stormwater Management: The primary driver behind the green roof was to mitigate stormwater runoff. Traditional roofs allow rainwater to flow directly into the city’s sewer system, potentially overwhelming it during heavy rainfall. The green roof acts as a sponge, absorbing a significant portion of the rainwater, slowing its release into the system, and reducing the risk of flooding and pollution.
• Energy Efficiency: The vegetation and soil layer provide insulation, helping to regulate the building’s temperature. In the summer, the green roof reflects sunlight and reduces heat absorption, minimizing the need for air conditioning. In the winter, it provides an extra layer of insulation, helping to retain heat and reduce energy consumption.
• Urban Heat Island Effect Mitigation: Cities tend to be warmer than surrounding rural areas due to the concentration of concrete, asphalt, and other heat-absorbing materials. This is known as the urban heat island effect. Green roofs help to cool the city by absorbing sunlight and releasing moisture through evapotranspiration.
• Air Quality Improvement: The vegetation on the green roof helps to filter pollutants from the air, improving air quality in the surrounding area.
• Aesthetic Enhancement: While not the primary driver, the green roof adds a touch of natural beauty to the urban landscape, creating a more visually appealing environment.

Target Center Green Roof: A Pioneer in Sustainability

The Target Center’s green roof was installed as part of a larger renovation project completed in 2017. It was a key component of the arena’s efforts to achieve LEED (Leadership in Energy and Environmental Design) certification. The installation involved several layers, including a waterproof membrane, a drainage layer, a filter fabric, a growing medium (soil), and the vegetation itself. The chosen plants are typically drought-resistant and low-maintenance, able to thrive in the rooftop environment.

A Closer Look at the Green Roof System

The Target Center’s green roof isn’t just a patch of grass randomly planted atop the arena. It’s a carefully engineered system:

• Waterproof Membrane: This is the foundation, protecting the building from water damage. It’s crucial for the integrity of the structure.
• Drainage Layer: This layer ensures proper drainage, preventing waterlogging and root rot.
• Filter Fabric: This layer prevents soil particles from clogging the drainage system.
• Growing Medium: A specially formulated soil mix that provides the nutrients and support needed for the plants to thrive.
• Vegetation: Selected for its hardiness, drought tolerance, and ability to withstand the harsh rooftop environment. Sedums are often a popular choice.

Frequently Asked Questions (FAQs) about the Target Center’s Green Roof

Here are some frequently asked questions about the Target Center’s green roof, providing more in-depth information:

FAQ 1: What type of plants are used on the Target Center’s green roof?

Typically, sedums are the primary plant species used. Sedums are succulents known for their drought tolerance, low maintenance requirements, and ability to thrive in shallow soil conditions. Other hardy and low-growing plants might also be included in the mix.

FAQ 2: How much does the green roof weigh?

The weight of a green roof varies depending on the type and depth of the growing medium. A saturated green roof can add significant weight to the structure. The Target Center’s green roof was carefully designed to ensure that the building’s structural capacity could handle the added load.

FAQ 3: How is the green roof maintained?

Green roofs require regular maintenance, including weeding, fertilization, and irrigation during dry periods. The Target Center likely has a dedicated team or contractor responsible for maintaining the green roof’s health and appearance.

FAQ 4: Does the green roof attract birds or other wildlife?

Green roofs can attract birds, insects, and other wildlife, adding to the biodiversity of the urban environment. This can be seen as a positive impact, contributing to a more balanced ecosystem.

FAQ 5: How long will the green roof last?

With proper maintenance, a green roof can last for decades. The lifespan of the roof depends on the quality of the materials used and the level of care it receives.

FAQ 6: Is the green roof accessible to the public?

Typically, green roofs on commercial buildings like the Target Center are not accessible to the public for safety and security reasons.

FAQ 7: How much did it cost to install the green roof?

The cost of installing a green roof varies depending on the size, complexity, and materials used. Green roofs are typically more expensive than traditional roofs, but the long-term benefits, such as energy savings and stormwater management, can offset the initial cost.

FAQ 8: What are the long-term benefits of having a green roof?

The long-term benefits include reduced energy consumption, improved stormwater management, reduced urban heat island effect, improved air quality, and increased biodiversity.

FAQ 9: How does the green roof contribute to the Target Center’s LEED certification?

The green roof contributes to LEED certification by earning points in several categories, including stormwater management, energy efficiency, and sustainable site development.

FAQ 10: Are there other green roofs in Minneapolis?

Yes, Minneapolis has embraced green roofs as a sustainable building practice. Several buildings in the city feature green roofs, contributing to a greener and more sustainable urban environment.

FAQ 11: How does the green roof help with noise reduction?

The soil and vegetation layers can absorb sound waves, helping to reduce noise pollution from outside the building.

FAQ 12: What lessons can other arenas and stadiums learn from the Target Center’s green roof?

The Target Center’s green roof serves as a model for other arenas and stadiums looking to incorporate sustainable building practices. It demonstrates the practical benefits of green roofs in terms of stormwater management, energy efficiency, and environmental stewardship. Arenas and stadiums can significantly reduce their environmental impact and contribute to a more sustainable future by embracing similar initiatives.