Like many cities across the country, strong population growth over the last few decades created infrastructure challenges for the Denver suburb of Westminster, Colorado.

Example: Big Dry Creek, which runs right through the heart of Westminster City Park. As Westminster grew from a town of 20,000 in the 1970s to a city of 120,000 today, the creek was straightened and simplified. The changes sped up the creek’s current, eroded its banks and diminished its habitat.

To set a new course, the City of Westminster and the Mile High Flood District enlisted Olsson and a team of design partners to develop a plan to restore Big Dry Creek. In addition to Olsson, the team included Stream Landscape Architecture + Planning, Element Engineering (now part of Bowman), and IRIS Mitigation. Naranjo Civil Constructors and Western States Reclamation completed the construction.

Big Dry Creek is now a place for people again.

The restoration project was strategically timed so construction sequencing would impact the community only once. Instead of selecting the most severely degraded reach in the watershed, Westminster identified a location where the goals of multiple departments aligned: protecting infrastructure, improving water quality, and enhancing a well-loved public park.

Rather than imposing rigid controls, the team chose to work with the creek’s natural tendencies.

• The channel was skillfully realigned and reshaped to restore sinuosity and long-term stability.

• The floodplain was reconnected, allowing high flows to spread, slow down, and dissipate energy.

• Riffle-pool systems and bioengineered banks replaced hardened infrastructure, guiding the creek toward a more balanced and resilient form.

The restored creek is now a place for people again.

New trails and stream crossings provide diverse experiences for users while still maintaining safe egress during flood events. Benches and picnic tables invite visitors to linger, while an outdoor education area encourages stewardship of this cherished natural space.

The park now attracts not only people but also wildlife. A boardwalk brings visitors closer to the historic Big Dry Creek alignment and a mature wetland area that was protected throughout construction. A pollinator flyway, developed in coordination with the nearby butterfly pavilion, was incorporated into the trail system, with pollinator plantings clearly demarcating the corridor.

The Colorado Association of Stormwater and Floodplain Managers named Big Dry Creek one of three finalists for their annual engineering excellence award.

Given the site’s role as a major community venue, construction was phased to accommodate public access and ensure safe passage during events.  

The success of the Big Dry Creek Restoration Project lies in collaboration. Engineers, landscape architects, ecologists, local partners, and multiple Westminster municipal departments worked together to align floodplain management goals with environmental restoration and community values. Olsson led engineering, design, and permitting services, including channel restoration, floodplain permitting, water quality improvements, and structural design for bridges and retaining walls.

While the project brought a previously developed park in line with modern design philosophy, it also anticipated future needs.

Rather than hauling excess earth off site, surplus material was strategically placed to support Winchester’s long-term plans for additional ball fields. Future road alignment and parking were accounted for in both grading and trail layout.

As with any living system, flexibility will be required moving forward. Drought-driven water restrictions are expected to impact initial vegetation establishment, and MHFD and Western States Reclamation will actively manage the site during early growing seasons.

The project remedied the problems of the past, created a healthy and thriving space for the present, and prepared for future community growth. Big Dry Creek now stands as a model for how thoughtful, process-based design can transform a degraded system into a lasting community asset, delivering flood protection, ecological integrity, and public benefit in equal measure.

Earlier this year, the Colorado Association of Stormwater and Floodplain Managers named the Big Dry Creek project one of three finalists for its annual engineering excellence award. The winning project will be announced in September.