Location – Longmont, Colorado
Completed – 2019
The restoration of Left-Hand Creek was achieved by creating a pattern, dimension, and profile that was more appropriate to the valley type and stream type. The design was intended to give the channel better connection to the floodplain. The realignment and restoration of the channel created a single, more defined, narrower channel with deeper pools. The realignment allowed the stream to connect with the floodplain, increasing its hydrologic connectivity. Therefore, allowing riparian habitat, including wetlands, to establish a higher degree of diversity than pre-construction conditions. The project was designed to restore 2,177 feet of Left-Hand Creek. In addition to grading the channel and associated floodplain (to remove spool piles/ berms), the design incorporated a constructed boulder riffle and wood toe with soil/ geolift. Willows and cottonwoods were harvested and transplanted on site. These transplants were installed at appropriate elevations along the stream bank and floodplain. A re-vegetation plan was developed and installed to speed up vegetation establishment. This included trees in the flood plain, and willows along the meander bends to jump start the bank stabilization. The design also incorporated 4 vernal wetland depressions which were designed to reduce scour along existing eroded sheer banks during a flood event and support habitat for miner bees and swallows.