Restoring the North Saint Vrain: Button Rock Preserve
by Barbara Luneau
Article originally APPEARED in High country angler, summer 2018
Button Rock Preserve is a 3000-acre protected park located approximately 7 miles northwest of Lyons, Colorado. Longmont and Ralph Price Reservoirs are located within the Preserve along North Saint Vrain Creek. This watershed provides the majority of the drinking water for Longmont and Lyons. The preserve also is a favorite place for many people across the northern Boulder County region to hike, fish, and enjoy nature. The City of Longmont manages the preserve via the Button Rock Forest Stewardship program, which focuses on preservation of the fragile natural environment.
The resiliency of the preserve and water supply was seriously threatened in September 2013 when up to 17 inches of rain fell over a 60-mile swath of the northern Front Range over a 6-day period. The result was major flooding in several watersheds, including all three forks of Saint Vrain Creek. The flood triggered landslides, and caused extensive channel erosion, deposition, and planform change with associated damage to property and infrastructure.
Before: flood flow downcut a defunct dam, creating a barrier to fish movement and fragmenting the stream.
After: rock ramp established to enhance fish passage and ensure single population group in the 1.3 mile reach between the Ralph Price and Longmont reservoirs
Within the preserve, North Saint Vrain Creek typically flows at 30 to 40 cubic feet per second. Peak flood stage flows were not measured; however, it is estimated to have been as much as 12,000 cubic feet per second. Water bypassed Button Rock dam through the overflow spillway and ripped apart the landscape. Enormous scour pools formed at the rock headwall opposite the spillway. Water overtopped the creek, eroding the banks and wiping out service roads. Debris dams made up of trees, brush, rock, and sediment built up and released, causing additional extreme bank erosion. The reservoirs became catchments for the debris and sediment. After the flood waters receded, a barren, denuded landscape remained. The trees and brush that lined the river requiring a delicate roll cast were gone. The reservoirs were full of ripped up trees requiring months of debris removal. The preserve remained closed to the public until June 2015.
Following the flood, a massive restoration response took place across the northern Front Range watersheds that were damaged. Button Rock Preserve was one of the first public access areas along Saint Vrain Creek to undergo restoration. The restoration efforts at Button Rock represent a collaboration among many stakeholders, including the local St. Vrain Chapter of Trout Unlimited. Planning efforts at the municipal and agency level dominated the year of 2014. While Master Plans were being created, the St. Vrain Chapter partnered with Michael Clark and South Creek Limited to fundraise.
The 2014 Cane Conclave became a major benefit to raise funds for Button Rock Preserve restoration. Together with the generosity of the Conclave supporters, we raised more than $30,000 to use as seed money for additional grant funding. Instream restoration in the preserve took place over 2 phases in late 2015 and 2016-2017 fall/winter. In addition to St. Vrain Chapter and South Creek Limited, the project stakeholders included City of Longmont, Boulder County Open Space, Colorado Parks and Wildlife, Wildland Restoration Volunteers, and Saint Vrain Creek Coalition. The City of Longmont served as the fiscal agent and project manager. The local fundraising contributed, required cash match for a number of grants from sources including: DOLA CDBG-DR Watershed Resilience program, CPW Fishing is Fun, and Great Outdoors Colorado. The combined effort of the stakeholders yielded over $500,000 of funding for the project. With nearly 2 miles of damaged stream within the preserve, the available funds necessitated focusing instream restoration to the most damaged reaches. Bill Schenderlein of Blue Earth Solutions LLC generated a design that included an assessment and ranking of reach damage. A multistage channel was re-established within 3 major reaches where scouring, braiding, and extensive erosion had removed pool and riffle structures. Riffle and pool structures were enhanced and hardened in less damaged areas. Fish passage was re-established at several locations at dams, diversions, and large rock structures where downcutting during flood stages had created barriers and segmentation of the stream. The final stages of the project included extensive riparian restoration and rebuilding an ADA accessible fishing structure that was washed away in the flood.
Before: channel severely eroded from flood impact, removing pool structures and leaving a uniformly shallow stream bed
After: channel re-established with connected pool-riffle structures
This project demonstrates a successful collaboration where municipalities, agencies, and non-profits can work together for public benefit. The funds raised by the St. Vrain Chapter turned out to be a critical component of the project’s success – both by demonstrating co-funding for grants and by having the flexibility of unrestricted funds to complement the more restricted grant funds. The overall result of the collaboration was to expand funding sources and reduce project risk. As we approach the 5-year mark postflood, the numerous stakeholders can celebrate a successful restoration in a beloved community resource, Button Rock Preserve.