The Globeville Landing Park project in Denver, Colorado is the reimagining of a larger, regional stormwater facility that serves a historically underrepresented community, addresses environmental contaminants, and honors the site's historical and cultural context. The existing park was designed in 1974 and is located along the South Platte River between the National Western Center Campus and the River North neighborhood. It is also the location where the largest drainage basin in Denver discharges into the river through an unsightly and unsafe concrete lined channel. Rainfalls that were greater than a two-year storm event caused extensive surface flooding to numerous residences, businesses, and roadways. An ideal approach would have been to construct an open channel with the capacity to convey the 100-year flow to the river, however, due to the dense existing development and lack of open space, this was simply not practical or feasible.

The City and County of Denver and the Mile High Flood District embarked on a project to create a conduit system to alleviate this drainage problem. The team designed 4,500 linear feet of concrete conduit to carry the 100-year stormwater event under several train tracks, roadways, and through an existing Superfund site. The conduit system outfalls in Globeville Landing Park in a location where much of the runoff from the basin naturally enters the river.

Several goals were identified at the outset of the project: create unique engineering strategies for the treatment of stormwater and conveyance of the floodwaters to the river, provide appropriate interventions for the contaminated site, involve adjacent communities in park program development, and use the context and history of the site to create a unique urban park space. Architerra Group, Inc. collaborated with the design team to find solutions to complex engineering issues with ecology, habitat, aesthetics, and community in mind.

Storm Drainage System
The storm drainage system was improved to contain the 100-year storm event and provide improved flood protection for over 5,000 residences and businesses. An open, more natural stormwater outfall was designed to provide wildlife habitat, ecosystem restoration, and improve water quality. The outfall is designed to dissipate the high-energy flow of water and features a stable, impermeable lining beneath the open channel to separate and protect surface water flows from contaminated groundwater. These improvements were integrated into the redesigned park space.

Architerra worked closely with an ecological consultant to design a wetland channel that maximizes treatment and habitat diversity. The grading of the channel created different hydrologic zones for different seed mixes and plugs. Close collaboration with the geotechnical engineer/liner designer was also required to protect the liner and obtain federal approvals. A variety of forbs and grasses were specified to provide maximum water quality benefits, habitat improvements, and protect the channel liner.

 
An intake structure was required to drop the stormwater flows under the sanitary sewers. This structure's unusual 300' long by 3' tall design minimizes flow velocity during storm events for public safety and is barely visible to park users. A ten-year storm event flows through the intake structure while anything greater flows over a spillway to the channel and river below. Architerra worked closely with the engineering team to design a multipurpose lawn and concrete walk that functions as an "invisible" spillway and enhances the park usability.

The project incorporates numerous principles of sustainability including addressing environmental quality through improved habitat and natural ecosystems; incorporating disaster resilience through floodplain engineering, conserving water by creating limited turf areas surrounded by native plants and grasses, redevelopment of a previously environmentally contaminated site, and improving the quality of life for the community around the park.

Smelting Plant Impacts
The site was a smelting plant from the late 1800s until 1950. The operations resulted in extensive environmental contamination of the site which led to eventual EPA Superfund designation in 1989. As a result, this project hauled off much of the contaminated soil, provided a synthetic liner under the open channel outfall so contaminated groundwater cannot mix with stormwater, and capped the rest of the contaminated soil in place.

Community Impacts
The team conducted a 15-month public process to provide project information and obtain input about the community's vision for the park. Interviews, surveys, workshops, open houses, site visits, focus groups, and meetings at elementary schools and recreation centers were conducted to maximize input. All meeting materials were presented in Spanish and English to support the outreach efforts.

A regional trail runs through the project site, creating connections throughout the Denver Metro Area. This project brought the trail up to current design standards and improved safety by making a wider cross-section and separating bicycle and pedestrian uses. Additionally, the trail elevation was raised above the 10-year water surface elevation.

The original park was overgrown with dense, largely invasive vegetation, which made the park feel unsafe to users. The new park provided views into the park from adjacent properties and added pedestrian lighting to improve safety for park users.

Historical Use as Design Inspiration
Architerra drew inspiration from the smelting process to design the park, educate visitors about the history of the site, and create unique project elements.

Smelting produces metal from ore found in rock by transforming raw materials to metal byproducts. Two "Raw Materials Plazas" bookend the site and showcase quarried stone slabs and sandscape pavement to reflect materials brought from nearby mountains. Colored pavement ribbons signify mineral seams and define the pedestrian promenade, connecting the plazas and other park elements. The pedestrian promenade continues to the "Metallurgical Plaza" which is a community gathering place and central park hub with a large shelter. The shelter columns include gabion baskets containing crushed rock.

The playground includes a custom climbing wall which features a natural-looking cliff face, transitions to quarried blocks for climbing, and a tipping crucible slide to reflect the molten metal processed from the raw materials. The molten metal pouring out of the crucible is delineated in the rubberized playground surfacing.

Finally, the "Chimney Overlook" located along the streetscape is sited near the location of the former smokestack for the smelting plant. When the smokestack was built in 1892 it was the tallest in the world, standing 350 feet tall, and was a Denver landmark for 60 years. The Landscape Architect created this overlook plaza with the same dimensions as the base of the smokestack. A "Chimney Shadow" planting bed reflects the height of the smokestack on the ground plane with a metal gateway at the end to illustrate the height of the structure and its impact on the land.

Globeville Landing Park serves as a model for integrating a regional outfall into an urban park within a historically contaminated ecosystem. The collaborative design team lead the effort toward a fully integrated, elegant, dynamic design solution to a complex technical and regulatory challenge. The extensive public process allowed the Landscape Architect to fully understand and implement the community's vision for this important park. It is a prime example of reimagining underutilized sites to provide health and social benefits to adjacent communities and the regional network beyond.