2025 | American Council of Engineering Companies (ACEC) of Colorado, Merit Award in the Water Resources Category

Ralston Creek flows from the mountains west of Golden through Arvada, between neighborhoods, parks, and urban infrastructure until it joins Clear Creek. The Ralston Creek Improvements project is a section of Ralston Creek at Croke Canal, located near the West Woods subdivision just west of the Croke Canal crossing. This area was heavily impacted by the September 2013 floods, resulting in channel instability, property damage, and embankment breaches along the Croke Canal. The City of Arvada partnered with the Mile High Flood District (MHFD) to improve stream health, enhance flood resilience, and restore the stability of Ralston Creek. Olsson was selected as the design engineers with Valerian as the landscape architects. With the new improvements, Ralston Creek at Croke Canal is designed to contain a 25-year flood event. Improvements include a sculpted concrete drop structure, bank protection, resilient channel design features, strategic tree removals in the stream corridor, and new tree plantings with native vegetation throughout the site for wildlife habitats.

In addition to addressing the creek challenges, the design team improved the layout and safety of the multi-use Ralston Creek Trail with better alignment and sight lines. The pedestrian bridge was replaced with a larger, flood-resilient structure so it no longer constricts the floodplain. Alongside the stream and trail improvements, Valerian designed a new community recreation area along the creek, including a soft surface trail, reclaimed log features (from the tree removals), boulder features, and seating areas. Naranjo Civil Constructors completed construction in the fall of 2025 and revegetation will be monitored throughout establishment. Through partnership and collaboration, this project restores Ralston Creek while balancing flood protection, recreation, and environmental stewardship.