Introduction

In this important water law decision, the Colorado Supreme Court affirms a water court’s partial dismissal of the Town of Firestone’s application for conditional groundwater rights and associated augmentation plan for three proposed well fields in the over‑appropriated South Platte River basin. The dispositive issues were:

• What “reasonably accurate” means when an applicant must quantify lagged depletions from tributary groundwater pumping to demonstrate non‑injury to senior surface rights;
• Whether a water court may use retained jurisdiction to let an applicant prove non‑injury later, after entry of the decree;
• Whether an opposer may contest non‑injury at trial despite a Rule 11(b)(6) joint statement listing certain topics as undisputed; and
• Whether the water court’s fact findings were clearly erroneous.

The only active opposer at trial was the St. Vrain Sanitation District, on whose land one of Firestone’s proposed well fields would sit. Firestone’s augmentation modeling relied on unit response functions (URFs) calculated for representative locations within quarter‑quarter sections rather than for specific well coordinates, with a proposed decree (its “Paragraph 48”) that would have allowed later updating of URFs and locations under retained jurisdiction. The water court held Firestone’s showing insufficient and rejected the retained jurisdiction workaround. The Supreme Court affirmed.

Summary of the Opinion

The Court held that:

• Applications for conditional groundwater rights accompanied by augmentation plans must be assessed case‑by‑case. The applicant bears the initial burden to show its depletions will be replaced in time, place, and amount so no injury occurs to vested senior rights.
• On this record, Firestone failed to meet that burden for three well fields (FAST North, Firestone Trail, and St. Vrain Sanitation District) because its well locations and URFs were not sufficiently specific to yield reasonably accurate lagged depletion estimates. Dismissal without prejudice was proper.
• Retained jurisdiction under section 37‑92‑304(6) is not a vehicle to postpone an applicant’s initial non‑injury showing. Because the water court could not first determine non‑injury, it properly declined to retain jurisdiction and struck Firestone’s proposed Paragraph 48.
• The water court did not abuse its discretion in allowing St. Vrain to contest non‑injury notwithstanding a joint Rule 11(b)(6) statement listing some issues as “undisputed,” because (a) the statement reserved the right to revisit issues, and (b) parties cannot stipulate questions of law such as the non‑injury determination.
• The water court’s fact findings were supported by the trial record and thus not clearly erroneous.

A two‑justice dissent would have reversed and remanded, concluding the water court applied an overly strict version of “reasonable accuracy,” demanded “exact locations,” and made unsupported findings about Firestone’s knowledge of well siting and types.

Analysis

Precedents Cited and Their Influence

• City of Aurora ex rel. Utility Enterprise v. Colorado State Engineer, 105 P.3d 595 (Colo. 2005): Established that an augmentation plan must enable a water court to make a “reasonably accurate” determination of the timing and location of depletions and the availability of replacement water before finding non‑injury. Also emphasized that retained jurisdiction serves to revisit injury after a decree is operating, not to defer the initial non‑injury showing. The Court relies on Aurora to require a sufficiently specific, location‑sensitive URF analysis at the application stage.
• Buffalo Park Development Co. v. Mountain Mutual Reservoir Co., 195 P.3d 674 (Colo. 2008): The burden to introduce reliable evidence of the quantity, timing, and location of depletions and legal availability of replacement water rests with the applicant and “cannot be postponed to occur under retained jurisdiction.” This case directly forecloses Firestone’s Paragraph 48 approach.
• Upper Eagle Regional Water Authority v. Wolfe, 230 P.3d 1203 (Colo. 2010): Clarified that section 37‑92‑304(6) reflects legislative intent for retained jurisdiction to reconsider injury determinations the court previously made—again, only after an initial non‑injury finding.
• Upper Eagle Regional Water Authority v. Simpson, 167 P.3d 729 (Colo. 2007) (dissent emphasis): Described an “integrated inquiry” under section 37‑92‑305(8)(a) into whether a proposed plan would cause injury, acknowledging the inherent uncertainty in predictions. The dissent invokes Simpson to argue the water court demanded undue precision.
• City & County of Denver ex rel. Bd. of Water Commissioners v. Colorado River Water Conservation District, 696 P.2d 730 (Colo. 1985) and City of Thornton v. Bijou Irrigation Co., 926 P.2d 1 (Colo. 1996): Addressed how precisely structures must be identified for notice and appropriation purposes. The water court treated these cases as context‑dependent and distinguishable, concluding quarter‑quarter descriptions can sometimes suffice, but not where site‑specific depletion modeling is indispensable to the non‑injury showing.
• Farmers Reservoir & Irrigation Co. v. Consolidated Mutual Water Co., 33 P.3d 799 (Colo. 2001) and Centennial Water & Sanitation Dist. v. City & County of Broomfield, 256 P.3d 677 (Colo. 2011): Provided the general injury framework (protecting time, place, and amount) and the purpose of augmentation in replacing out‑of‑priority depletions, including lagged depletions.
• Lake Meredith Reservoir Co. v. Amity Mutual Irrigation Co., 698 P.2d 1340 (Colo. 1985) and Bar 70 Enterprises, Inc. v. Tosco Corp., 703 P.2d 1297 (Colo. 1985): Confirmed trial courts’ discretion to disregard stipulations and the rule that parties cannot stipulate questions of law, respectively—key to allowing St. Vrain to contest non‑injury despite the Rule 11 statement.

Legal Reasoning

1) “Reasonably Accurate” Requires Site‑Specificity When Location Drives Depletions

The Court reaffirmed that “reasonable accuracy” is not a rigid formula but a case‑specific standard. However, where tributary groundwater pumping depletes a surface stream and the magnitude and timing of those “lagged depletions” are highly sensitive to a well’s precise location, the applicant must tie its URF modeling to sufficiently specific, intended points of diversion to demonstrate non‑injury.

The water court found that Firestone’s plan for three well fields lacked the requisite specificity—Firestone had not fixed the number, placement, or type (vertical vs. horizontal) of wells, and its URFs were based on representative points (centroids) within quarter‑quarter sections rather than the actual future wells. Firestone’s own experts conceded that small locational shifts (e.g., 150 feet) or local boundary conditions (e.g., unlined gravel pits) could materially change the URF and thus the timing/amount of required replacements. On those facts, the Court held that the non‑injury showing failed.

Importantly, the Court rejected the notion that this amounts to a new bright‑line rule requiring completed construction to obtain a conditional groundwater right. Quarter‑quarter descriptions can suffice “in certain contexts.” Here, though, given the sensitivity of modeled depletions to exact well position and design, greater site specificity was necessary to achieve “reasonable accuracy.”

2) Retained Jurisdiction Cannot Substitute for the Applicant’s Initial Burden

Firestone asked the water court to decree the augmentation plan now and allow later updates to URFs and well locations under retained jurisdiction (Paragraph 48). The Supreme Court deemed this contrary to Aurora, Buffalo Park, and Upper Eagle (Wolfe): retained jurisdiction exists to reconsider injury after a decree is operating, not to postpone the applicant’s initial non‑injury proof. Because the water court could not first find non‑injury, it properly declined to retain jurisdiction and struck Paragraph 48.

3) Stipulations and the Non‑Injury Question

The trial court did not abuse its discretion in allowing St. Vrain to contest non‑injury despite a joint Rule 11(b)(6) statement that had previously listed certain URF depletion patterns as “adequate to prevent injury.” The joint statement expressly reserved objections and was conditional on evolving case understanding. More fundamentally, non‑injury is a question of law (or at least a mixed question) that parties cannot conclusively stipulate. The court had an independent duty to be satisfied as to non‑injury on the record presented.

4) Fact Findings Survive Deferential Appellate Review

The record contained expert admissions supporting the water court’s concerns: well number and placement were unsettled; URFs could vary within a quarter‑quarter; directional design (horizontal vs. vertical) and proximity to St. Vrain Creek and gravel pits could change depletion timing/amount; and URF inaccuracies risk under‑replacement. Under the clearly erroneous standard, the Supreme Court found ample support for the water court’s findings and declined to reweigh the evidence.

The Dissent’s Counterpoint

Justice Gabriel (joined by Justice Boatright) would have reversed and remanded. In the dissent’s view:

• The water court effectively demanded “exact locations,” misapplying the “reasonably accurate” standard from Aurora and ignoring that augmentation adjudications inherently involve uncertainty (Upper Eagle v. Simpson).
• Firestone provided approximate locations (including a map with intended well sites), likely distances from St. Vrain Creek, and well types (e.g., a horizontal well at ~250 feet for the Sanitation District field), which should have allowed a reasonably accurate injury assessment—especially where one expert testified URFs at 250 feet would be similar across the quarter‑quarter.
• Some of the water court’s findings (e.g., that Firestone did not know locations or types for certain wells) were not supported by the record.

The dissent would thus require the water court to apply the correct legal standard to the facts as properly found.

Impact

This decision is likely to have immediate, practical effects on groundwater development and augmentation practice in Colorado, particularly in over‑appropriated basins:

• Front‑loading specificity and modeling: Applicants should expect to present well‑specific (or closely bounded) URFs tied to actual intended coordinates or a rigorously supported, narrowly defined siting envelope. Quarter‑quarter descriptions, standing alone, may be inadequate if URFs are materially location‑sensitive.
• No “defer now, fix later” via retained jurisdiction: Decrees may not incorporate flexible update mechanisms that defer the applicant’s initial non‑injury burden. Retained jurisdiction can recalibrate operations, but only after the court has first found non‑injury on a reliable record.
• Design choices matter: Applicants should account for orientation (horizontal vs. vertical), well spacing, and local hydrogeologic boundaries (e.g., gravel pits, stream proximity) in their URFs and provide sensitivity or worst‑case analyses demonstrating protection under all plausible configurations.
• Litigation strategy and Rule 11 practice: “Undisputed issues” in trial management filings may not insulate an applicant from legal challenges at trial where stipulations reserve rights or address legal/mixed questions. Plan for full proof on non‑injury.
• Municipal planning and finance: Municipalities contemplating bond‑funded supply expansions may need to budget for earlier siting decisions, test wells, and detailed hydrogeologic work to meet the non‑injury burden at the application stage.
• What remains open: The Court did not forbid quarter‑quarter descriptions categorically; in contexts where URFs are not materially sensitive to intra‑parcel location or where robust bounding analyses prove non‑injury across the entire envelope, quarter‑quarter descriptions might suffice. The line will be drawn on the facts of each case.

Complex Concepts Simplified

• Conditional water right: A placeholder priority that preserves an appropriator’s place in line while they diligently complete the project to put water to beneficial use.
• Augmentation plan: A court‑approved plan allowing junior out‑of‑priority diversions if the junior replaces depletions to protect seniors, including “lagged” impacts that reach the stream after pumping.
• Lagged depletions: The time‑delayed effect that pumping tributary groundwater has on nearby surface flows; the impact may unfold over days to years depending on local hydrogeology.
• Unit response function (URF): A modeling tool that estimates the timing and magnitude of stream depletions caused by a given well’s pumping, typically sensitive to the well’s exact location and aquifer/stream parameters.
• Glover equation: A common analytical model used to estimate stream depletions from wells in a confined or unconfined aquifer, incorporating transmissivity, aquifer thickness, and distance to stream.
• Retained jurisdiction (section 37‑92‑304(6)): A statutory period during which the water court may revisit injury after an augmentation plan is decreed and operating. It is not a mechanism to postpone the initial non‑injury showing.
• Quarter‑quarter description: A 40‑acre land description (one‑quarter of a quarter section). While often adequate for notice, it may be too coarse for proving non‑injury where depletion modeling is highly location‑sensitive.
• C.R.C.P. 41(b)(1) motion: In a bench trial, after the plaintiff’s case‑in‑chief, the defendant can move to dismiss on the ground that the plaintiff failed to prove a right to relief.

Conclusion

Firestone underscores two enduring tenets of Colorado water law. First, the applicant—not the court or the Division Engineer—must carry the initial burden to present reliable, reasonably accurate evidence that its replacement water will cover the timing, location, and amount of depletions, including lagged effects. When URFs are sensitive to well location, “reasonable accuracy” demands well‑specific or tightly bounded siting and modeling. Second, retained jurisdiction cannot be used to defer that burden; it is a tool for post‑decree oversight once a non‑injury finding has been made.

The decision does not erect a new bright‑line rule requiring completed wells or exact coordinates in every case. It does, however, sharpen the practical message: where location drives depletions, general legal descriptions and representative centroids will not do. Applicants should expect to front‑load hydrogeologic specificity or provide conservative, protective modeling that convincingly demonstrates non‑injury across the full range of plausible well configurations. Stipulations cannot waive the court’s duty to ensure non‑injury, and courts will be afforded deference when the record supports their fact findings.

For water developers and municipalities in over‑appropriated basins, Firestone is a roadmap and a caution: build the modeling record you will need on day one—or risk dismissal without prejudice and delay.