State agencies recommend new in‑stream flow right for East Fork Roaring Creek in Larimer County

Larimer County commissioners heard a presentation Oct. 20 from state water agencies recommending a new in‑stream flow water right for East Fork Roaring Creek, a tributary of the Poudre River near Cameron Pass, intended to help sustain fisheries including greenback cutthroat trout.

Mariel Bridal, a hydrologist with the Colorado Water Conservation Board (CWCB), and Katie Birch, an instream flow specialist with Colorado Parks and Wildlife (CPW), described the recommendation and the multi‑year state process for creating new in‑stream flow rights. The recommending entity for this reach is CPW; the CWCB is the state agency that would hold any new in‑stream flow appropriation on behalf of Colorado.

The agencies described biological field work and hydraulic modeling used to quantify flows that would “preserve the natural environment to a reasonable degree,” language the presenters said derives from the statute that created the program. CPW biologists reported field measurements from riffle cross sections and recommended roughly 1.0 cubic foot per second (cfs) for winter/base flows and about 2.9 cfs for higher summer flows at the East Fork site to meet the biological criteria specified for greenback cutthroat trout. Katie Birch said CPW’s interest in the reach is focused on protecting and reestablishing greenback cutthroat trout, a Colorado native listed as federally threatened.

Why it matters: agency staff said an in‑stream flow water right held by CWCB would operate within Colorado’s prior appropriation system and is intended to provide legal certainty for stream flows that sustain fisheries and riparian habitat. CWCB staff emphasized the process is designed to avoid material injury to existing water rights while protecting the natural resource identified by the recommender.

How the process works: presenters outlined a minimum three‑year timeline from a recommending entity’s initial work to CWCB board action. After CPW (or another recommender such as Larimer County, the U.S. Bureau of Land Management, or conservation groups) develops a biological recommendation and flow quantification, CWCB staff evaluate water availability and potential injury to other water users, present the recommendation at a public workshop and board meetings, and ask the board for intent to appropriate and later for final action. Mariel Bridal said the CWCB intends to bring the East Fork recommendation to its board beginning in January and that, for uncontested recommendations, final determinations are typically brought for board decision in May; contested recommendations can proceed to hearings in later months.

Commissioners asked for clarification about key points in the statute and technical standards. Commissioner Faucette asked how the statutory phrase “reasonable degree” is given objective meaning; Bridal said the program’s analyses of hydraulic parameters, medium‑streamflow statistics and the “no material injury” review are the practical way staff apply that standard. Commissioners also asked about post‑fire watershed stability and restoration work; presenters said stabilization and restoration efforts are typically handled by forest and watershed programs (for example, CWCB’s watershed health section and federal or local land managers), not by the in‑stream flow appropriation itself.

No action required of the county: staff from CWCB and CPW told the commissioners that Larimer County does not need to sign off on the in‑stream flow recommendation. The agencies asked the county commissioners to be aware of the process in case local constituents contact them. CWCB staff recommended they be contacted with questions and noted contact information and the presentation will be available on the CWCB website.

Context and next steps: CWCB staff described three statutory findings the board must make before creating a new appropriation: (1) a natural environment exists that is appropriate for protection; (2) water is legally and physically available to preserve that environment; and (3) the appropriation will not cause material injury to other water rights. Staff said they prefer medium‑streamflow analyses (median daily flows) to avoid overstating available water and that public notice and comment are part of the board stage. The presenters also referenced Senate Bill 73‑97 as the origin of the in‑stream flow program and noted more recent legislation and rule changes (including rule 6(k), as described by staff) that affect how the CWCB may use leased or purchased reservoir water in support of in‑stream flows.

Commissioners thanked the presenters. CWCB staff said they will present the East Fork Roaring Creek recommendation to the CWCB board beginning in January and continue the statutorily required analysis and public process.