Confluence Park, Denver—Where the Waters Meet

Editor, Stephen Kelly

The river’s edge at Confluence Park is defined by a concrete trail and two overlooks with boulders for sitting or stepping down to get to the river. The bank was stabilized with buried riprap. The landscape architect added numerous willow stakes to the waterfront along the park perimeter and spread a riparian seed mix that included western wheatgrass (Pascopyrum smithii), alkali Sacaton (Sporobolus airoides (Torr.), switchgrass (Panicum virgatum), green needlegrass (Nassella viridula), blue grama (Bouteloua gracilis), sandburg bluegrass (Poa sandbergii), and plains coreopsis (Coreopsis tinctoria). You see large existing cottonwoods (left); the smaller trees closest to the cottonwoods are sargent cottonwoods (Populus sargentii). The trees lining the walkway are swamp white oak (Querus bicolor) and Bosnian pine (Pinus heldreichii var. leucodermis) in the interior. Buffalo and blue grama are the native grasses.

The project site, the historic birthplace of Denver located at the confluence of Cherry Creek and the South Platte River adjacent to 15th Street, was home to an electrical substation since the 1950s. The city worked with the power company for over a decade to relocate the substation and convert this prominent site to a public park. The old Confluence Park consisted of a lawn amphitheater across from Cherry Creek and a plaza across the river. Confluence Park was somewhat isolated from adjacent streets and was accessible only by the trail system.

AFTER: This aerial photograph reveals the park improvements. The existing retaining walls were removed and the site terraced to open up the area and put the focus on the river.

BEFORE: An aerial photograph before work began on the new park shows the old substation situated about 15 feet above the South Platte River. The old park consisted of a lawn amphitheater (just above the substation) and a plaza on the other side of the river (left). The city worked with the power company for over a decade to relocate the substation and convert the prominent site to a public park.

The purpose of the project was to give the park a street presence, open views to the waterways, provide trail connections, and give residents a gathering place adjacent to the river. The design intent was to cut a formal opening through a restored native landscape. A plaza was created along 15th Street with shade structures and a “vista bar” overlooking the confluence. A mid-level terrace includes tables with umbrellas and offers solitude from the street above. The lower level includes a flat lawn area adjacent to the river and two overlooks with boulder steps for direct access to the river. The mid and lower levels are accessible by stairs on the formal axis and ramps off to the side. Design elements reflect the importance of water in the settlement of Denver.

The concrete wall is capped with red sandstone (see detail above) and the concrete has a light broom finish. The xeriscape grasses are Karl Foerster feather reed grass (Calamagrostis x acutiflora Karl Foerster) and little bluestem (Schizachyrium scoparium). The trees are skyline honeylocust (Gleditsia triacanthos. var. inermis ‘Skyline’).

Role of the Landscape Architect

The landscape architect firm for the project, The Architerra Group, was the prime consultant for the public input, design development, construction documentation, bid administration and construction administration. The landscape architects conducted extensive public input to allow resident to help shape the vision for the park, then coordinated a team of artists, environmental consultants, geotechnical, civil, hydraulic and structural engineers.

The landscape architect also worked closely with a nonprofit organization to provide renderings and fundraising brochures.

The plan includes a plaza along 15th Street, a mid-level terrace, a lawn area and two river overlooks. The edges are restored landscapes with native plantings and grasses. The center of the park is more formal with bluegrass and street trees.

Public/Private Partnership

The project began with city funding, but because of citywide budget cuts, the project budget was cut in half shortly after the master plan was completed! The landscape architect recommended the city partner with a local nonprofit organization to allow the project to move forward with limited city funding. The nonprofit was able to raise significant funds from the private sector. Part of the selection for hiring the contractor was based on the contractor’s ability to donate a portion of its bid to the nonprofit for tax credits. The construction budget ended up being only $800,000. Rather than putting the project on the shelf, this adaptive partnership allowed the project to proceed despite the funding limitations. The challenge for the landscape architect was to look for creative ways to make the project successful and not compromise the quality of the design.

There are ponderosa pines (Pinus ponderosa) in the foreground and swamp white oak (Quercus bicolor) in the middle section, surrounded by gro-low fragrant sumac shrubs (Rhus aromatica ‘Gro-Low’). The grasses are a native seed mix of buffalo grass (Buchloe dactyloides) and blue grama (Bouteloua gracilis).

Public Art

With a limited budget it would seem an inopportune time to look at expanding the project scope. However, to make this park truly unique and special, the landscape architect brought on a public artist during the design work, feeling that unique, artistic amenities would make fundraising easier. The landscape architect and artist worked with local school groups, first educating them about the river and its natural processes. These groups then visited the site, discussed the design and had the students draw numerous shapes and patterns of things inspired by what they saw along the river. These patterns and shapes became cutouts on the shade structure panels, which created interesting shadows on the pavement. These sketches also led to sculptures of the leaf, duck and fish in the plaza. The sculptures were carved out of different colored granite with bronze accents. Granite blocks were carved into bar stools at the “vista bar” and seating under the shade structures. The importance of water is reflected in the abstract ripple-paving pattern in the plazas, and the concentric circular layout of the terrace walls.

This is the detail for the ornamental railing of the vista bar pictured below.

Creative Phasing

The landscape architect prepared construction documents for the basic park improvements and infrastructure knowing that the fundraising for the amenities would take additional time. The plaza areas were paved in crusher fines that were later removed for the granite pavers. The strategy was to show improvements as soon as possible to give credibility to the project, allow people to see the progress and get excited about contributing to the effort. One day a family was walking their elderly patriarch along the trail system and came upon the new park. The substation had been there for as long as he could remember. He was so delighted with the new improvements that he became a major benefactor to the upper plaza, funding the sculptures and the granite pavers.

The overlook from the plaza features the “vista bar,” with carved granite stools and a railing top panel that is convenient for placing food or drink upon. Sandstone caps the concrete wall. The landscape architects visited the My Brother’s Bar, the oldest watery in Denver, to research the proper proportions for the park bar stools: barstool (30-in.), footrests (12-in.) and counters (42-in.). ASPI supplied the St. Andrews grey granite for the seats.

Visualization

One of the strengths of landscape architects is the ability to think three dimensionally and visualize their designs. The Architerra Group explains: “This project required a huge leap of faith as the substation and its 15-foot high screen walls were not removed until after the park construction documents were completed and bids secured. We were not allowed on the substation site. Even if we were, it would have been impossible to see over the walls. We had to trust our instincts as we could not observe the vistas and visualize the proposed design.”

An ornamental railing is featured at the “vista bar” on this side of the river. On the other side of the river, railings with a historic motif were selected. This is the detail of the historic railing.

The granite pavers (Architectural Stone Products) are St. Andrews grey and mahogany granite and patterned based on three intersecting ripples. The layout started as a hand drawing. That concept-sketch was used to layout the pattern in Illustrator to determine the square footage of each color and the cross patterning of the ripples. Artist Andy Dufford of Chevo Studios worked in the field with the installers to adjust the pattern to the realities of installation. From the plaza you look out on the confluence of the Cherry Creek and the South Platte River. The railing on this side of the river has an ornamental design; on the other side are railings with a historic motif.

Environmental Responsibility

The design includes a formal bluegrass lawn for active pedestrian use but the rest of the park is designed with water-conserving xeric plantings. Native grasses tie the park into the surrounding landscape of Commons Park and the riverbanks. Stormwater runoff is filtered by native willow plantings before sit enters the river.

The plaza includes three shade structures, three sculptures, carved granite seating and granite pavers. Andy Dufford was the lead artist for all these amenities. The granite pavers evoke the shape and pattern of water ripples connecting the plaza to the river below.

Balancing Aesthetics and Engineering

The entire site is located in the 100-year floodplain so the improvements were designed to withstand flood velocities. The landscape architect worked closely with the engineers to ensure the armoring improvements were buried and did not impact the aesthetic qualities of the park. Live willow stakes were installed in the riprap protection to soften the river’s edge.

The artist carved a fish out of Michigan mahogany granite. The sculptures are roughed out using a wire saw and diamond chain saw, then the form refined with a nine-inch diamond saw, pneumatic hammers and hand chisels. The final finishes are a combination of bush hammer, flame finish and high polish. The details are then sandblasted.

he artist carved a leaf out of green African granite with a hand-fabricated bronze stem. The curved granite seating is aimed inward to encourage social interaction.

Swedish blue pearl granite comprises the body of the abstract duck sculpture; the head is mahogany granite and the beak is bronze.

Contextual Design

The landscape architects note it was important to fit the park improvements into the urban context. The selection of the boulders at the river overlooks match the low-flow channel boulders along Cherry Creek and the adjacent kayak course on the South Platte River. The Cherry Creek Trail was extended along the bank under 15th Street to connect to the existing trail system in Commons Park. The shade structures are similar in architectural detailing to the Commons Park shade structures and the arch bridges of Speer Boulevard to the south. Existing mature cottonwood trees were preserved and integrated into the design. The existing accessible ramp was maintained. Railings were designed to match existing historic railroad bridge railings.

The panels of the shade structure include patterns and shapes developed by local school children. The manufacturer of the shade structures is Independent Sign; the paint color is PMS 444C grey-green.

Significance

Confluence Park began with the South Platte River cleanup efforts in 1975. The original vision of a grand park at the symbolic birthplace of Denver is finally a reality. Located on the semi-arid plains, the importance of water to the citizens of Denver cannot be overstated. The design for Confluence Park celebrates water through the materials, patterns, sculptures, and direct focus on the waterways that determined the location of the city. This was done while conserving water with native landscaping.

The Architerra Group landscape architects realized the importance of the vision for this park and did not waver when faced with a budget crisis. The ensuing public/private partnership led to the successful completion of the park. Working with the public and the local schoolchildren, the landscape architects educated them about natural processes, design vocabulary and how to merge the two. Confluence Park reconnects the citizens of Denver with their waterways.

Upon a recent visit to the park, the landscape architects observed children swimming in the river, families eating dinner on the mid-level terrace, couples having coffee at the “vista bar” and children climbing on the sculptures. The citizens seem to be embracing their new park as if it had always been there.

The mid-level terrace continues the granite pavers and provides seating and shade from Landscape Forms. The four-seat backed “Carousel” steel tables are painted federal green; the “Altair” aluminum and stainless steel umbrellas are powder-coated a cranberry color. The trash receptacles are a Denver city standard (MC402-FT Manchester, BRP Enterprises). The trees are swamp white oak (Quercus bicolor) and the shrubs gro-low fragrant sumac (Rhus aromatica ‘Gro-Low’). A bluegrass lawn is at the lower level.

About The Architerra Group, Inc.

The Architerra Group, Inc. was founded in 1999 to bring landscape architectural consulting services to public sector clients—planning and design services for recreational parks; passive open space parks; multi-use trails; streetscapes; urban spaces; educational facilities; and environmental restoration.

The Architerra Group takes projects from the conceptual design stage and is usually involved in the bidding/ construction administration. “This experience provides us with knowledge of current construction practices, pricing trends and the proper contractual language to protect the best interests of our clients,” says the firm.

The staff includes two licensed landscape architects, with a combined 30 years of experience, who play an active role in all projects. The support staff is highly educated and trained and active in promoting landscape architecture through the ASLA and in the Denver community through numerous volunteer projects.

Confluence Park, Denver Colo.

Client/Owners: Jeff Shoemaker, the Greenway Foundation; Bar Chadwick, Denver Department of Parks & Rec.Landscape Architect: The Architerra GroupPrincipals: Dean Pearson and Mary Olson

Chevo Studios: Lead artist Andy Dufford (shade structures, sculptures, carved granite seating and granite pavers)