The Sydney & Walda Besthoff Sculpture Garden at NOMA Infrastructure
Size of Project
Number of Keys
New Orleans, LA
The New Orleans Museum of Art
Completed in 2019
Reed Hilderbrand + Lee Ledbetter & Associates
Rejuvenation of a natural and sustainable foundation.
Dirt and water are part of everything our Infrastructure Team does. For the extension of NOMA’s Sydney & Walda Besthoff Sculpture Garden, they were central players. In 2016, Impetus was selected as the Design-Assist contractor for NOMA’s 6.5-acre expansion. The addition would bolster the museum’s outdoor exhibits and educational offerings by rejuvenating a natural and sustainable foundation. Partnering with Reed Hilderbrand Landscape Architects and Sherwood Engineering, Impetus’ Infrastructure Team took charge of the Sculpture Garden’s sustainability focus, including the revitalization of the 11-mile-long water system and the installation of green infrastructure components. As a company that isn’t afraid to dive into the unknown, we knew our early participation in development and budgeting would be pivotal for implementing the architect’s ideas. We also knew a challenge like this would once again show why our “renegade” moniker continues to stick.
Improve and stabilize.
To improve and stabilize the shoreline, the Infrastructure Team drained the lagoon within the perimeter of the Sculpture Garden. The water was channeled into another lagoon and held back with two AquaDams. Through team expertise and consultant support, we conducted soil sampling to better understand what needed to be done. However, the soil quality was four times as poor as previously thought, finding that those layers of earth contained sediment deposits due to a lack of oxygen. Over many years, this led to reduced water depths, lower oxygen levels, and a negative impact on lagoon wildlife. To improve on the mucky soil, our team got creative with equipment. Long-reach excavators were brought in, extending from the more stable parts of the lagoon, to reach and scoop out the mud. Then, 20,000 cubic yards of clay soil were brought in as a base layer for the bottom of the lagoon, along with 30,000 cubic yards of pumped river sand to build the new land along the shoreline. In total, 50,000 cubic yards of dirt and muck were removed and replaced with environmentally appropriate soil. Within the garden expansion, the Infrastructure Team increased the lagoon’s perimeter from 22,000 to 26,000 linear feet through wetland edge treatments and man-made cypress islands that prevented edge erosion and filtered water before entering the lagoon. A portion of the lagoon was also rehabilitated with a variety of soils to create one of the garden’s new features: an in-grade amphitheater and stage.
Translating complex ideas into fruition.
Green infrastructure was vital to augmenting the lagoon’s revitalization and sustainability. Where the architect and engineer offered the idea and design, it was up to our Infrastructure Team to make it happen. This included curb cuts to direct perimeter street water through culverts and into bioswales. The bioswale, a long underground channel system, was installed to filter sediment and slow runoff from the top with vegetation, reducing pollutants before the rainwater reaches the lagoon. The team also improved the lagoon’s overall water levels by installing a new automatic weir. The weir would work in tandem with the 300-ft Canal bridge, a submerged concrete shell walkway connecting the two sculpture gardens with a design that gives visitors the impression of moving through water. The bridge’s railing elevations match those of the weir structure, and in the event of a heavy rainstorm, the water would drain into a notch cut into the length of the walkway. The water would channel into a sump pump behind the bridge wall and back into the lagoon. Meanwhile, the weir would control the water back to a normal level. All of these green infrastructure components work in tandem to improve the water quality and support the spatial experience of the Sculpture Garden’s extension.
Proof of passion.
NOMA’s Sydney & Walda Besthoff Sculpture Garden expansion opened in 2019. Among the 19th-century sculptures, oak trees, irises, pathways, and bridges, is a foundation of sustainability. The improved shoreline, healthier soil, and augmented water flow were bolstered to support the museum’s engaging yet tranquil outdoor space for years to come. But it’s also proof of passion. Beyond their expertise, our dynamic Infrastructure Team cares deeply for their craft. Their work and ability to execute in a high-stakes environment produced a natural stage for elevated concepts. And even when unforeseen challenges occur, such as a dam failure or flooding, this team’s grit and grind sets them apart. Yet, despite all that, the result of this one-of-a-kind project produced an experience that our team, their families, and the community can share for generations to come.