Upper Colorado River

Located downstream of Lake Granby, Freestone was tasked with enhancing this 0.8-mile stretch of the Colorado River. Primary objectives of this project were to design and construct a multi-stage channel that would accommodate flows as low as 30 cubic feet per second (cfs) up to 1200 cfs, increase sediment transport, increase dissolved oxygen concentrations, and maintain habitable stream temperatures. The Freestone Aquatics design called for the enhancement of existing riffle-pool conditions and introduced low elevation point bars to promote flow concentration during periods of low flows. Pool depth was increased and riffle structure function was enhanced through careful streambed modification. Spawning area was increased through the placement of repurposed, sorted excavated material generated through pool excavation. Project highlights on this stretch of the Colorado River include; increased deep water holding habitats, increase in riffle structure area resulting in greater macroinvertebrate abundance, increase in large wood associated with over 85-feet of bio-engineered bank stabilization, in-stream large woody structures, and floodplain connectivity during high flow events. Freestone performed all baseline conditions evaluation, design, permitting, construction and post construction monitoring. Freestone’s post-construction evaluations reflect a fully functioning low flow channel with enhanced structures withstanding all potential high flow effects.