LaVERN M. JOHNSON PARK

LaVern M. Johnson Park River Restoration and Whitewater Park

A recreational wave on the North St. Vrain Creek

Low Flow Fish Passage Channel

The kids natural outdoor play river channel allows kids to move boulders to create a variety of water features and to splash and play in the water.

Multi-use field adjacent to the North Saint Vrain Creek

RV camping along the North Saint Vrain Creek

2D modeling of a drop structure

Lyons, Colorado

Nearly all of the park’s amenities, which were a focal point and revenue generator for the Town of Lyons, were damaged or destroyed during the September, 2013 flood. S2o was the lead designer and engineer for all river components and the lead engineer for the park site plan.

S2o was tasked with re-establishing the parking and camping areas and to ensure the park could continue to host several annual festivals during the 2014 summer season. The improvements included: 96 parking spaces, 22 RV camping spots, 9 tent camping spots, landscaping and hardscaping, and the construction of a large multipurpose field. The project was completed on an expedited design and construction schedule.

S2o completed all stream restoration planning, design, and construction oversight. S2o’s stream restoration design included a grouted rock ramp diversion structure for the Lyons Ditch and eight grouted rock ramp whitewater park structures. All grouted rock ramp structure designs implemented a variety of techniques to facilitate fish passage. These techniques included a low slope notch to decrease velocities at critical low flows, grout set six to eight inches below rock surfaces to provide interstitial spaces, and ramp stages set at alternating elevations to reduce velocities on the structure shoulders as stages increase with higher flows.

S2o’s design also included the restoration of fish habitat. In the reaches between the whitewater park structures, riffles were maintained to increase fish and macro-invertebrate habitat. An adjustable split flow channel included a riffle pool sequence that incorporated large woody debris, random boulders, and stream barbs.

Project Highlights

– Parking lot and RV capacity of the park was expanded.
– Increased flood conveyance through expanded floodplain benches and a split flow channel.
– The first collaborating effort with Colorado Park and Wildlife to combine whitewater recreation improvements with fish and aquatic habitat enhancements.
– S2o’s fish passage techniques are being researched and analyzed through a series of three dimensional hydraulic models by Colorado Park and Wildlife aquatic research scientists.