Project Hosts: Boulder County Parks & Open Space, City of Longmont Natural Resources, The Watershed Center
St. Vrain Creek is the largest drainage basin within Boulder County, and despite over a century of impacts from water diversions, development, floods and forest fires, still retains many important natural features, and is home to Federal and State threatened wildlife species like the Preble’s Meadow Jumping Mouse and the Northern Redbelly Dace.
In 2013, a historic flood event breached a dozen ponds and reservoirs along St. Vrain Creek between Lyons and Longmont, CO resulting in substantial flood damage throughout the corridor. In 2020, the largest wildfire in Boulder County history burned over 10,000 acres of forested watershed resulting in heavy sedimentation and high flows. In response to these events, several county, municipal, non-profit, and private stakeholders collaborated on several restoration projects throughout the St. Vrain Creek corridor, as well as in multiple other watersheds throughout Boulder County.
On this field trip, we will visit several restoration projects along St. Vrain Creek, highlighting multiple goals and objectives seeking to boost ecosystem function, uplift habitat quality, increase climate resilience and protect water resources and communities from future flood and fire events.
Transportation is provided between sites, but walking within sites will include on-trail, gravel paths as well as off-trail terrain on uneven ground.
Recommended for field trip: long pants, long-sleeves and layered clothing, sturdy closed-toed shoes, sunhat, sunglasses, sunscreen, water bottle.
Meals & Logistics: Lunch and bathrooms will be provided at the third stop, Pella Crossing. See the detailed description below.
Left to right: Beaver dam in restoration site in Lyons, CO. Channel reconstruction at restoration in Hygiene, CO.
Left to right: Emergent wetland restoration at Pella Ponds, St. Vrain Creek in City of Longmont RSVP
Detailed Description
The field trip will travel a length of St. Vrain Creek from Lyons, CO, a small foothills community, to Longmont, CO, a growing city of nearly 100,000 residents. We will visit several restorations along the way learning about various project goals at each site which include protecting infrastructure while increasing floodplain connectivity and aquatic habitat complexity, increasing riparian vegetation diversity, balancing agricultural water delivery with natural habitats and native fish passage, creative use of flood sediment deposits for habitat creation, and urban stream uplift and public amenities development.
At our first stop in Lyons, we will visit restorations that incorporated diverse climate adaptation features across the floodplain such as braided channels, back water and seeps, beaver mimicry structures, instream rock structures, bioengineered bank stabilization and instream and floodplain large wood structures. Project goals sought to maximize floodplain connectivity and geomorphic complexity that maximize ecological function while reducing impacts from future flood and fire events on water resources and communities. We also hope to see our newly resident beavers, who have recently ‘found’ this improved habitat.
Our second stop will be in Hygiene, CO, and highlight riparian restoration, native fish passage, federally threatened species conservation, ditch conveyance improvement and stakeholder collaboration. This site aimed to preserve decreed water rights to existing ditch infrastructure while also providing fish passage for small bodied native fish and brown trout. As well, it was necessary for this design to reduce high flow energy directed at the adjacent railroad ballast and ditch headgates, and use these constraints to creatively increase floodplain connectivity, native riparian vegetation, and aquatic and terrestrial wildlife habitat, including the federally threatened Preble’s Meadow Jumping Mouse.
Lunch will be provided at Pella Crossing, the third site on this field trip. This is a popular Boulder County park with regular use by public visitors who experience rich birding, fishing, exercise, and solace. This project highlights creative use of sediment deposition from the historic 2013 flood event to create 3 acres of emergent wetland, a habitat type rarely found in past gravel mining reclamation efforts. This area is also home to an urban beaver population, which requires active management to mitigate flooding of the trail and emergent wetland habitat. This combination of species has proven to be a lesson in coexistence and solution-driven decision making.
Our fourth stop brings us to the City of Longmont to visit part of a multi-year project called the Resilient St. Vrain Project (RSVP) at Dickens Farm Nature Area. This site will highlight a portion of the approximately 3-mile reach of RSVP that included reconstructing water treatment utilities, irrigation ditch diversions, recreational amenities, improving native fish passage, enhancing aquatic and terrestrial habitat, and improving stream function through natural channel design. The Resilient St. Vrain Project includes reconstruction of the St. Vrain Greenway and improvements to the urban St. Vrain Creek channel to protect the community from future flood risk.
If time allows, we may make a 5th and final stop at Peschel Open Space, a jointly owned property between Boulder County Parks and Open Space and the City of Longmont. This site represents a flood recovery effort centered on passive restoration, letting the plant communities naturally develop and go through succession on their own with the main intervention being weed control. It was determined that the ecological benefits of allowing the creek to stay where it is post-flood, were greater than putting it back through designed and engineered restoration.