Water records, wetland maps, wildlife observations and the standards that guide a County decision. Save Homestake opposes Whitney Reservoir. This record shows what supports that position and which decisions still need a documented answer.
Read measured data, calculations, modeled exposure and regional science in plain language, with direct paths to the supporting material.
Read the evidence family
Executive Evidence Brief
A short visual introduction to the evidence and decision questions.
The October 27 package expressly includes fens in the definition of Waterbody. Sections 307(E)–(F) address groundwater levels, wetland function and connections between floodplains and stream channels. Section 406(C)(3) protects wetland structure, function and extent from significant deterioration in the impact area. Read the two sets of wetland provisions.
How source labels work
CASE, MASTER, BRIEF, 1041 and HWF identify different original bibliographies. A number belongs to its named bibliography, so similarly numbered entries remain distinct. The source register preserves the original labels and links.
During WY2007–2024, recorded Homestake Tunnel export totaled 420,676.93 AF and flow passing Gold Park totaled 386,968.01 AF. Across these two recorded routes, 52.09% was exported through the tunnel and 47.91% passed Gold Park.
Geography
Gold Park gauged catchment, USGS 09064000; official drainage area 35.6 square miles
The denominator is the sum of two recorded routes, not a verified estimate of all natural Homestake runoff. Lower Homestake tributaries below Gold Park are outside this gauge comparison.
Why it matters
Whitney would add a reservoir and collection works to a headwater system already exporting about 23,400 acre-feet a year.
Recorded Homestake Tunnel export averaged 23,370.94 AF/year during WY2007–2024; flow passing Gold Park averaged 21,498.22 AF/year over the same 18 water years.
Geography
Gold Park gauged catchment / whole Homestake Tunnel export
In water years 2007–2020, estimated rain and snow water equivalent totaled 860,947 acre-feet across the Gold Park watershed. Homestake Tunnel exports totaled 326,828 acre-feet and 326,778 acre-feet passed Gold Park. Homestake Reservoir storage fell 642 acre-feet. Applying the snow-sublimation, reservoir-evaporation and mapped-fen plant-and-soil estimates leaves an unaccounted remainder of 4,292–6,921 acre-feet per year, or 6.98–11.25% of estimated precipitation.
Geography
USGS 09064000 Gold Park StreamStats watershed, 35.9029 square miles
Period
WY2007–2020
Calculation
860,946.7113 − 326,827.9062 − 326,778.2678 − (40,611.73 − 41,254.0313) = 207,982.8386 acre-feet before the natural-process estimates over 14 matched water years. Divide by 14, then subtract 7,068–9,402 acre-feet per year of snow sublimation, 812–971 of reservoir evaporation and 55–191 of mapped-fen plant-and-soil evaporation. Remaining balance: 4,292–6,921 acre-feet per year. Each percentage = component ÷ estimated precipitation × 100; remainder bounds pair high process estimates with the low remaining balance and low estimates with the high remaining balance.
Method
Sum matched annual PRISM 800-m rain and snow-water-equivalent estimates, DWR tunnel export and integrated USGS Gold Park discharge. Count signed reservoir storage change as end minus start. The snow estimate applies the archived 15–20% seasonal-snow scenario; the reservoir estimate applies its 35-inch fixed-surface-area evaporation scenario. These are screening assumptions. The mapped-fen estimate uses 165.324 acres of confirmed and potential fens and the full 101–353 mm partial-season evaporation range in Blanken 2014 Table 5, including the drought year. Fen evaporation combines plant transpiration and soil or wet-surface evaporation. Broader forest and meadow water use and net groundwater crossing the watershed boundary remain unquantified within the remainder; groundwater returning to the creek above Gold Park is already included in its recorded flow.
Scope
All displayed water-balance totals share water years 2007–2020. Natural-process ranges are scenario estimates; the fen estimate covers a partial season on mapped confirmed and potential fens. The remainder also includes unresolved storage, precipitation and measurement differences.
Why it matters
The balance shows the scale of existing exports alongside watershed precipitation, creek flow, storage and estimated natural processes, with the unaccounted portion reserved for what remains after those estimates.
Colorado forest-opening surface-only losses equaled 13% and 17% of winter precipitation. Canopy and blowing-snow terms are outside that surface-only result.
Regional process model including surface, canopy and blowing-snow sublimation. The reported 22-36% range, mean 28%, is a regional sensitivity benchmark, not a calibrated Gold Park estimate.
Table 5, full 101–353 mm partial-season ecosystem evaporation range, including the drought year; applied to 165.324 mapped confirmed and potential fen acres.
Colorado headwater process analogue showing interflow, groundwater contribution and groundwater-supported ET. Recharge and baseflow are internal pathways unless water crosses the accounting boundary or changes storage.
Adding endpoint storage change and recorded evaporation accounts to the two-route denominator gives a partial-balance export comparison of 51.75% for WY2007–2024.
Geography
Gold Park gauged catchment / existing project accounting
This partial balance is not completed naturalization or an uncertainty interval. External inflow, project-induced net losses, reservoir precipitation, evaporation relative to the no-project landscape, and measurement corrections remain unresolved. The separate net-flow-reduction formula uses a different numerator and answers a different question.
Gold Park measures Homestake Creek downstream of Homestake Reservoir. Water exported through Homestake Tunnel travels south through the mountains to Lake Fork Creek and then into Turquoise Lake near Leadville.
Geography
Homestake Valley and Lake Fork Creek above Turquoise Lake, Colorado
Period
Mapped locations checked October 5, 2026
Method
North-up locator rendered in UTM zone 13 from retained USGS lake, creek and tunnel geometry. Gold Park uses the USGS 09064000 location, 39.4055426° N, 106.4333620° W. The tunnel outlet uses USGS 09063700, 39.2805556° N, 106.4405556° W. Shading uses the point-specific USGS StreamStats drainage boundary at Gold Park, about 35.9 square miles, matching the basin used for the precipitation accounting. A dashed brown line depicts the mapped underground tunnel; blue lines depict surface creeks.
Scope
Mapped geographic locations and route, with a 2-km scale.
Why it matters
The map locates the two recorded water routes: creek flow continuing through Homestake Valley and exported water carried through the mountains to Turquoise Lake.
During WY2007–2011, recorded Homestake Tunnel export was 139,942.66 AF and recorded flow at Red Cliff was 185,166.87 AF. Export was 43.04% of their combined recorded total.
Geography
USGS 09064500 Red Cliff gauge catchment (58.2 square miles), a larger and downstream drainage than Gold Park
Preserves the original DWR-published USGS annual total; current USGS daily aggregation differs by 19.87 AF over five years. Gold Park and Red Cliff differ in drainage area, period and downstream contributions. They are separate comparisons, not an uncertainty range. Red Cliff town, gauge and the full Homestake mouth are distinct locations.
Sources and method
DWR-published USGS 09064500 Red Cliff water-year flow
DWR Homestake Tunnel monthly diversion records
Water class 13704614; Approved 216 monthly records for WY2007–2024
Five existing tributary intake records total 144,638.46 AF for WY2014–2024, averaging 13,148.95 AF/year. Annual averages are French 3,530.90, Fancy 1,779.67, Missouri 1,742.73, Sopris 2,485.52 and East Fork 3,610.13 AF/year.
Geography
Existing French, Fancy, Missouri, Sopris and East Fork intakes
Period
WY2014–2024
Calculation
144,638.4649 AF ÷ 11 water years = 13,148.95 AF/year combined. French 3,530.90; Fancy 1,779.67; Missouri 1,742.73; Sopris 2,485.52; East Fork 3,610.13 AF/year.
Scope
Collector records overlap subsequent reservoir and tunnel accounts. Never add collector capture to whole-tunnel exports as separate withdrawals. French and Sopris WY2016 capture accounts are Approved all-zero records; raw records are preserved and their physical interpretation remains an agency question.
All five existing Homestake tributary intake sites and Homestake Reservoir fall upstream of Gold Park in the retrieved USGS basin delineation. The station’s published drainage area is 35.6 square miles.
Geography
Gold Park upstream catchment
Period
September 23, 2026 spatial source check
Scope
The station’s official drainage area defines this comparison. The NLDI polygon follows a mapped flowline unit and has a different area. Gold Park flow combines bypass, releases and water never intercepted. It is neither natural runoff nor an individual tributary measurement.
The reviewed evidence identifies Whitney storage concepts of 6,850–20,000 AF and a broader Eagle River Joint Use objective of up to 20,000 AF/year. Whitney-only dependable annual yield remains an unresolved records question.
Geography
Whitney concepts / broader Eagle River Joint Use Project
Period
Reviewed record through September 23, 2026
Scope
Storage is a volume in AF; annual yield is a rate in AF/year. Demand savings and dependable yield are comparable on a common annual time basis with matching reliability assumptions.
Why it matters
Necessity, feasibility and alternatives turn on the reliable supply actually delivered.
The September 23, 2026 Homestake Valley BioBlitz snapshot contains 1,400 observations, 229 terminal taxon concepts and 190 species-rank concepts: 618 Research Grade, 778 Needs ID and four Casual records.
Geography
Homestake Valley BioBlitz project membership
Period
Snapshot September 23, 2026
Scope
Observation and taxon concepts are separate counts. Identification grades remain visible; this is an opportunistic project record.
The September 23, 2026 Homestake locality archive contains 233 occurrence records from GBIF, including 129 eBird reports, 103 specimen records and one other occurrence.
Geography
Homestake-area locality records in Eagle County, Colorado
Period
Occurrence records archived September 23, 2026
Method
Records selected by Eagle County and Homestake locality names.
Scope
A dated collection of reported observations and specimens from the generalized Homestake locality.
In Rocky Mountain National Park and nearby areas, 90% of the sampled summer locations were within about 285 metres of mapped water. The mean distance was about 110 metres.
Geography
Rocky Mountain National Park and vicinity, Colorado
Period
GPS data from 21 adults; 1,672 locations; 12-hour fixes, June–August 2017–2018
Method
21 adult moose; 1,672 GPS locations; June to August 2017 and 2018. Distance was measured to mapped flowing or standing water. The study used those observations to design an aerial survey.
Why it matters
Water and nearby willow and forest give moose a connected summer habitat mosaic.
Monitoring in Rocky Mountain National Park found that two beaver dams slowed seasonal groundwater decline across areas of 9 and 12 hectares, respectively.
Geography
Rocky Mountain National Park, Colorado
Period
Two beaver dams along 1.5 km of stream; 58-ha study area; monitoring 2002–2005
Method
Two dams along 1.5 kilometres of stream in one 58-hectare valley, monitored during 2002 to 2005.
Scope
Regional ecological evidence from Rocky Mountain National Park, Colorado.
Why it matters
A beaver pond can help hold water in the surrounding valley floor as summer flows recede.
At four previously drained Colorado fens, ditch blocking raised summer water tables. At the site restored 20 years earlier, disturbed surface peat still differed from reference peat.
Geography
Four Colorado mountain fens
Period
Four century-drained sloping fens restored 1–20 years previously; 89 wells at three short-term sites; 2008–2010 water tables and 2009–2010 growing-season CO2 flux
Method
Four Colorado mountain fens restored 1 to 20 years before study. This research examined restoration of existing drained peat.
Why it matters
Bringing water back and recovering the peat that holds it are different stages of recovery.
In northern California's upper Shasta River, drifting invertebrate prey approached zero below a diversion late in the season even though benthic biomass could be higher there.
Geography
Upper Shasta River, northern California
Period
One diversion in wet 2019; 13 sampling events Dec 2018–Dec 2019; 18 benthic and six drift sites; fish diets from one pool above and one below
Method
Regional comparison outside Colorado: one diversion during wet 2019, with 13 sampling events and limited fish-pool replication.
Why it matters
Food available on the streambed and food carried to a fish can respond differently when flow is diverted.
Canada lynx in the contiguous United States are federally Threatened; Colorado classifies the species as State Endangered. The July 16, 2026 final critical-habitat rule took effect August 17, 2026. Unit 6 includes portions of Eagle County.
Geography
Contiguous-US DPS; Colorado; Unit 6 includes portions of Eagle County
Period
Current status checked September 23, 2026
Scope
The cited designation establishes Unit 6 geography but not its boundary relationship to a selected project footprint.
The same downstream query envelope returned 18 Potential Fen features from the older CNHP service and six from Fens 2025. Five newer polygons overlap older polygons, one does not, and no pair has equal geometry.
Geography
Existing downstream map WGS84 envelope
Period
September 23, 2026 GIS comparison
Scope
Counts describe returned mapped features in the same downstream query envelope. The inventories differ in identifiers and geometry; their authoritative version correspondence, classification equivalence and currency remain unresolved. The September 18 source inventory underlies the September 20 modeled reservoir exposure and acreage.
Aurora's IWMP 2 already includes continued conservation in all demand scenarios, including reducing existing residential indoor use from 47 to 40 gpcd and reducing existing turf.
Geography
Aurora
Period
January 2025 IWMP2, Revision 1
Scope
These conservation savings are already included in Aurora’s demand baseline.
Aurora reports water-use reductions, Prairie Waters reuse and new-development turf restrictions. Colorado Springs Utilities reports a 40% per-capita consumption decline since 2001 and 276 AF/year of savings gained through its 2024 conservation programs. Planned conservation already included in forecasts must be separated from additional savings.
Geography
Aurora and Colorado Springs municipal systems
Period
Reviewed September 23, 2026
Why it matters
A fair alternatives comparison credits completed progress and tests further practical savings using the same time period and reliability assumptions.
Fens are groundwater-supported peat-forming wetlands. At a Colorado fen rewetted 20 years before study, disturbed surface peat still differed from reference peat. The soil that stores water can take much longer to recover than the water level itself.
Geography
General fen definition; four Colorado mountain fen restoration sites
Period
Reviewed September 23, 2026
Method
Four restored Colorado mountain fens, restored 1–20 years before study; regional ecological evidence.
Why it matters
Protecting the fen means retaining the conditions that build and sustain peat, as well as its mapped area.
On October 27, 2026, Eagle County’s Board approved standalone 1041 rules and made them effective upon passage of a separate enacting resolution. As of November 2, passage of that resolution and the effective date remained unverified. A Whitney Reservoir application would require its own county review.
Geography
Eagle County
Period
October 27 vote. County records checked through November 2, 2026.
Scope
Which rules govern a particular application depends on the enacted text, its transition terms and the application record.
Why it matters
The approved text explicitly names fens and addresses downstream flows, groundwater, wetland function and aquatic habitat. Those protections matter for the water that sustains the Homestake valley floor.
Save Homestake’s full-pool models of the four potential Whitney dam sites intersect shared mapped wetland and Potential Fen habitat. The retained inventory identifies the mapped resource categories within each modeled water surface.
Geography
Homestake Valley
Period
Reviewed September 23, 2026
Why it matters
The permanent and temporary project footprint needs to account for dam, reservoir, roads, power, pumping, tunnels, spoil and maintenance together.
Campaign interpretation of the mapped fen complex and modeled reservoir alternatives. Model-based conclusions concern the displayed alternatives and water elevations.
Save Homestake opposes Whitney Reservoir. Flooding these wetlands and taking more water from Homestake Creek would permanently harm the valley. Under the October 27 package, the Board must deny a permit if any applicable standard remains unmet after conditions. Proving municipal demand would not give the cities an ethical claim to the valley.
At the full-pool presets for the four potential Whitney dam sites, Save Homestake’s four modeled inundation areas share 81.4 acres of overlap with the dissolved mapped-wetland and Potential Fen inventory, excluding mapped-water categories.
Geography
Shared intersection of campaign-modeled A–D inundation areas and September 18 CNHP inventory
Period
September 20 model; reproduced September 23, 2026
Calculation
The four modeled water surfaces were overlaid with the mapped wetland and Potential Fen inventory. The area shared by every modeled alternative is 81.4 acres, excluding mapped-water categories.
Scope
Our modeled full-pool surfaces intersect the September 18 mapped inventory. Potential Fen is a mapping class, not field confirmation. Construction areas are separate from these water-surface overlaps.
Why it matters
Every option covers the same 81.4 mapped acres plus additional ground: about 4.0 acres for B, 13.5 for C, 46.0 for A and 53.4 for D. These differences give each option’s total footprint. Homestake’s fens and connected wetlands form the landscape at risk. The wider wetland system connected to Homestake Creek contains 362.1 mapped acres in 36 linked complexes across our Whitney-to-Eagle assessment, reaching the Eagle River confluence near Red Cliff. Additional water removal would ultimately impact all connected downstream wetland ecosystems. Potential Fen retains the source classification of particular mapped areas.
Shoshone is a hydroelectric plant on the Colorado River in Glenwood Canyon. It generates electricity with river water, then returns that water to the river.
Geography
Homestake Creek → Eagle River → Colorado River at Dotsero → Shoshone, Glenwood Canyon
Period
Rights appropriated 1902 and 1929
Calculation
Shoshone: 1,250 cfs with a 1902 priority, plus 158 cfs with a 1929 priority, totaling up to 1,408 cfs in water rights. Homestake project priority: 1952.
Method
The Colorado River Water Conservation District, often shortened to the Colorado River District, is a local government agency serving 15 Western Slope counties, including Eagle County. It protects the region’s water interests, with one board representative appointed by each member county. A water call is a senior holder’s request for state officials to enforce its priority when its supply is short. Officials can require affected junior upstream users to reduce or stop diversions, including reservoir filling, or provide lawful replacement water. Shoshone’s 1902 and 1929 rights precede Homestake’s 1952 priority. The Colorado River District agreed to acquire the water rights from Public Service Company of Colorado, an Xcel subsidiary. The plant would retain hydropower use through a lease. Under the November 2025 agreement, the Colorado Water Conservation Board would protect historic flows in the 2.4-mile Shoshone reach when the rights are not used for hydropower, carrying forward their original priorities after the required water-court approval and closing. The Colorado River Water Conservation District’s May 2026 update describes financing and approvals in progress. Closing requires the water-court change decree, full financing and Public Utilities Commission approval; the instream-flow agreement was approved in November 2025.
Scope
Water-right priorities, decrees and operating agreements govern how a call is administered.
Why it matters
These older rights help keep water flowing west through Homestake’s connected river network, sustaining fish habitat, farms and river recreation.
Caleb Foy, Deputy Division Engineer, Colorado Division of Water Resources, June 17, 2024. Slides 14 and 30: priority administration, augmentation and storage orders.
Colorado River Water Conservation District entry: Eagle County among the 15 counties; one county-appointed board representative per member county. Accessed October 5, 2026.
Across four Rocky Mountain national parks, a 2002-2011 analysis estimated 34% higher amphibian occupancy in beaver-influenced wetlands; four of five species had higher colonization rates.
Geography
Four Rocky Mountain national parks
Period
2002-2011
Method
Multi-year occupancy modeling of five wetland-breeding amphibians.
Scope
Regional occupancy association across four Rocky Mountain national parks, 2002–2011.
Why it matters
Shallow pond networks and the wet ground around them provide connected places to breed and move.
The 2025 White River National Forest inventory reports 56 confirmed/likely fen polygons covering 86 acres in French Creek-Homestake HUC12 and nine covering 45 acres in Whitney Creek-Homestake HUC12.
Geography
Named HUC12 watersheds in the White River National Forest
Period
2025 inventory
Method
Inventory distinguishes field-confirmed fen (>40 cm peat), peat-accumulating wetland, likely, possible and low-confidence fen. The 2025 update redraws fen-specific boundaries; the 2011 method rated existing NWI polygons that could combine fen and other wetland habitat.
Scope
2025 Forest Service inventory totals for the French Creek-Homestake and Whitney Creek-Homestake watersheds. Reservoir-overlap acreage is reported separately.
Why it matters
The inventory places Homestake within a documented peatland landscape whose value extends beyond any single reservoir outline.
A laboratory study of boreal chorus frog tadpoles from Colorado source ponds found limited developmental acceleration under simulated early pond drying.
Geography
Colorado Front Range source populations; laboratory experiment
Period
2012 publication
Method
Tadpole survival, development and size were compared under differing hydroperiod treatments.
Scope
Laboratory study of tadpoles from Colorado ponds under different pond-drying conditions.
Why it matters
When a pond dries too early, faster development may not be enough to complete the frog’s transition to life on land.
For matched down-valley gates, native cumulative ascent rises from 73.2 m in current terrain to 191.6 m in A-C and 191.3 m in D. Primary overall terrain cost rises 1.205% for A-C and 4.422% for D.
Geography
Whitney model area; matched central gates
Period
September 24, 2026 lidar addendum 2.0; 2016 terrain
Method
Directed least-cost routing on a 2 m grid with lidar-derived terrain, water masks and potential-face screening.
Scope
Terrain-route model between fixed endpoints. All 200 tested paths remain connected, with fewer relatively easy alternatives around the reservoir scenarios.
Why it matters
Flooding the valley floor displaces the easiest modeled passage onto the hillsides.
At a +5% common terrain-cost budget, modeled between-gate route-opportunity area falls 47.66%, 44.83%, 44.34% and 73.42% for A-D. At +10% the losses are 23.76%, 14.06%, 15.67% and 26.92%; at +20% they are 12.21%, 7.19%, 7.95% and 14.92%.
Geography
Whitney model area; same central gates and shared baseline cost budgets
Period
September 24, 2026 lidar addendum 2.0
Method
Area of cells that can participate in a between-gate route within a fixed budget above the baseline optimum.
Scope
Computational routing area under three terrain-cost budgets. Wider budgets admit more terrain and produce smaller losses.
Why it matters
A route can remain connected while the choice of easy ways through the valley contracts.
Wet years and high runoff can activate lower-energy side channels and backwaters. As lateral waters disconnect, persistent ponds and main-channel water can become more important; low main-channel flows can also permit seasonal dams. Severe or prolonged drying can remove usable depth, routes and forage access.
Geography
North Saint Vrain Creek and East River, Colorado; seasonal habitat interpretation for Homestake
Period
North Saint Vrain observations 2015, published 2017; East River low-water 2018, published 2022; guidebook 2023
Method
Synthesis of monitored water levels, reported dam construction and federal habitat guidance.
Scope
Colorado field studies of seasonal water levels and beaver dam placement.
Why it matters
Protecting both lateral channels and persistent water preserves options through snowmelt, summer recession and drought.
Wegener et al. 2017, North Saint Vrain Creek, Colorado, May-October 2015; sections 2.1 and 3.1, Figure 5: inferred June-July side-channel surface connection and relatively stable off-channel pond levels through October.
Dewey et al. 2022, East River, Colorado: main-channel dam construction during exceptionally low-water summer 2018; seasonal hydrology and figure captions.
Tesky 1993, U.S. Forest Service species review, habitat, food and cover sections; stable aquatic habitat, forage, underwater shelter access and fluctuating water levels. Accessed October 5, 2026.
Reduced water and destruction of connected wetland vegetation can constrain beaver shelter, forage, movement and dam maintenance. Reduced beaver activity can then weaken water retention, wet-meadow and willow habitat, and the pond-and-channel network used by other wildlife.
Geography
Homestake risk pathway supported by regional field studies and agency habitat accounts
Period
Research synthesis October 5, 2026; groundwater study 2002-2005, published 2006; fen study published 2018
Method
Connects habitat requirements with measured dam effects on water tables and regional interacting willow/beaver decline.
Scope
The local magnitude depends on water sources, duration of drying, dam condition and vegetation. Groundwater-fed fens, wet meadows and beaver ponds retain distinct water regimes.
Why it matters
Protecting the whole ecosystem means sustaining connected water, vegetation and habitat, including the functions maintained by keystone species such as beavers.
Tesky 1993, U.S. Forest Service species review, habitat, food and cover sections; stable aquatic habitat, forage, underwater shelter access and fluctuating water levels. Accessed October 5, 2026.
Karran, Westbrook and Bedard-Haughn 2018, Rocky Mountain fen: four intact-dam years and two post-breach years. Abstract reports raised, stabilized water tables and greater storage within a study-specific 150 m radius.
The September 23, 2026 Homestake BioBlitz snapshot includes six beaver observations from June 2024 to July 2026: four Research Grade and two Needs ID. Historical inventory records from 1983 imagery identify beaver-modified wetlands along lower Homestake Creek. CSU field observations published in 2005 describe intricate stream-wetland connections and three willow species in Homestake.
Geography
Homestake observation project; lower creek from Blodgett area to Eagle River; 2005 field assessment
Period
1983 inventory imagery; 2005 assessment; observations June 5, 2024 to July 11, 2026, frozen September 23, 2026
Method
Dated observation records, historical mapped wetland attributes and a published field account.
Scope
Six dated observation records, alongside beaver-modified wetlands identified in historical imagery.
Why it matters
Local observations and the historical inventory place beavers within Homestake’s connected stream, willow and wetland landscape.
Sources and method
Homestake BioBlitz dated observation records, September 23, 2026 snapshotDownload supporting data
Castor canadensis rows: 220819403, 220820056, 293591322, 298332228, 373241923, 381088423; June 5, 2024 to July 11, 2026; four Research Grade and two Needs ID.
Colorado State University 2005, Appendix A.1, printed A-39 (PDF p.43): Homestake stream-wetland connections and Geyer’s, mountain and diamond-leaf willow field observations.
Fens are groundwater-fed peat wetlands. In one Rocky Mountain fen, a comparison of four intact-dam years and two post-breach years found that beaver dams connected the peatland to the stream, raised and stabilized water tables and increased water storage.
Geography
One Rocky Mountain fen; process relevance to hydrologically connected Homestake wetlands
Period
Published 2018; four years with intact dams and two after breaches
Method
Field comparison of water-table dynamics before and after flood breaches.
Scope
Field comparison at one Rocky Mountain fen before and after beaver-dam breaches.
Why it matters
Keeping creek, groundwater and vegetation connections intact protects the water regime sustaining connected peatland and beaver habitat.
Karran, Westbrook and Bedard-Haughn 2018, Rocky Mountain fen: four intact-dam years and two post-breach years. Abstract reports raised, stabilized water tables and greater storage within a study-specific 150 m radius.
Beaver-supported water and vegetation provide different functions for different animals: amphibian breeding water, willow and pond habitat for birds, emerging aquatic insects and food for their consumers, fish refuge and movement routes, and wetland forage for moose. Losing pond water and willow removes breeding space, food and shelter from the connected habitat network.
Geography
Regional studies in Rocky Mountain parks, Wyoming, Kimball Creek Colorado and Washington; Homestake risk synthesis
Period
Amphibians 2002-2011, published 2015; Wyoming birds 2002-2003, published 2008; Kimball Creek 2011-2018, published 2025; Washington study published 2022
Method
Species-specific interpretation of occupancy, vegetation/bird associations, insect emergence, and storage/temperature studies.
Scope
The regional 34% occupancy increase is a relative difference in modeled occupancy. Kimball Creek emergence biomass increased while insect richness declined. Fish temperature and passage responses vary with reach conditions.
Why it matters
A loss of pond water or willow can remove breeding space, food and shelter for several parts of the same community.
Homestake Creek joins the Eagle and then the Colorado upstream of Shoshone, whose senior rights can constrain affected junior diversions. Colorado’s 2024 climate assessment finds that most projections show 5–30% lower annual streamflow by 2050 across its major basins compared with 1971–2000. On October 4, 2026, Lake Powell was 22% full and Lake Mead 26%; observed April–July 2026 unregulated inflow into Powell was 18% of normal. The 1922 Compact requires the Upper Division states not to cause Lee Ferry flow to be depleted below 75 million acre-feet over any rolling ten years. The 1948 Upper Basin Compact provides for reductions in use if needed to meet those obligations. The River District’s 2023 modeling, which included Eagle River–Whitney development, found greater export shortages under drier conditions. Interior’s August 2026 decision issued two-year operating guidelines for 2027–2028 within a framework through 2036.
Geography
Colorado River Basin; Homestake Creek → Eagle River → Colorado River; Shoshone in Glenwood Canyon; Lee Ferry, Arizona
Period
1922 and 1948 Compacts; 2015 planning framework; 2023 risk modeling; 2024 climate assessment; August 2026 operating decision; October 4, 2026 reservoir snapshot; April–July 2026 observed inflow.
Method
Reclamation’s October 5, 2026 Weekly Hydrologic Update reports storage conditions on October 4 and observed seasonal inflow. Its August 21 decision reports record-low reservoir elevations and 1.25 million acre-feet of annual Lower Basin state delivery reductions in 2027–2028. Compact Article III(d) governs non-depletion at Lee Ferry; Upper Basin Compact Article IV provides an interstate curtailment mechanism. The July 27, 2023 River District Phase IV presentation identifies Eagle River–Whitney among modeled future transmountain demands and links drier hydrology to export shortages and storage drawdown. The Legislative Council’s August 2018 handbook, page 17, summarizes the new-diversion planning framework incorporated in the 2015 Water Plan. Shoshone returns water after power generation; its November 2025 agreement seeks instream protection when the plant is offline, subject to the required approvals.
Scope
The 5–30% climate range covers most mid-century projections across Colorado’s major basins. The 2023 risk study evaluates hydrologic scenarios under then-current operating rules. Project-specific delivery restrictions depend on depletion accounting, governing rights and applicable administration. Reservoir operating rules, interstate Compact obligations and Colorado senior-right calls operate through distinct legal mechanisms.
Why it matters
Save Homestake’s conclusion is that additional Western Slope exports carry a material long-term risk to supply and investment. Hotter, drier conditions make capture and refill harder; shrinking reserves reduce drought protection; interstate obligations add the possibility of legal restrictions. Whitney’s lasting ecological costs must be weighed against dependable, legally deliverable water through prolonged drought.
Milly and Dunne, Science, March 13, 2020. Abstract: basin-scale hydrologic modeling links warming, snow loss and increased evapotranspiration to reduced Colorado River discharge.
Articles II(a), II(f), III(c)–(d), IV(c), VII and IX: river-system/out-of-basin service definitions; Mexico deficiency sharing; 75 million acre-foot ten-year non-depletion provision; state administration, Tribal obligations and enforcement rights retained.
Bureau of Reclamation decision documents, updated September 1, 2026. August 21, 2026 Record of Decision establishes a 2027–2036 framework; first operating guidelines cover 2027–2028.
Bolinger, Lukas, Schumacher and Goble / Colorado State University for CWCB. Climate Change in Colorado, Third Edition. 2024. Pinpoint: Chapter 3, key messages and 3.3.
Articles IV and VIII(d)(8): Commission findings on necessary curtailment and state shares; Article XV(b): state administration of available apportioned water; Article XIX: federal Tribal/treaty rights retained.
Dave Kanzer, Director of Science and Interstate Matters. PDF pages 3, 15 and 31: unmet transmountain demands under worsening hydrology; Eagle River–Whitney modeled demand; increasing export shortages under drier scenarios.
Legislative Council, State Water Policy, revised August 2018, printed page 17: framework incorporated in the 2015 Water Plan recognizes compact-deficit risk and calls on East Slope developers to accept hydrologic risk.
Record-low reservoir levels; 2027–2028 Lower Basin state deliveries reduced by 1.25 million acre-feet annually; two-year operating guidelines under a 2027–2036 framework.
Below Lake Powell elevation 3,490 feet, Glen Canyon Dam releases depend on four river outlet pipes. Reclamation identifies cavitation and conduit-damage risks that can restrict releases. Its 2025 recoating repaired minor cavitation damage found after the April 2023 high-flow experiment, but cannot prevent future cavitation. Hoover’s older turbines face severe cavitation damage below Lake Mead elevation 1,035 feet; a 2026 assessment puts potential capacity at 382 megawatts at that elevation. Reduced river flow has lowered generation at Davis and Parker while their reservoir elevations remain comparatively steady. Parker supplies water to the Colorado River Aqueduct and Central Arizona Project. The 2027–2028 rules seek a 3,510-foot Powell buffer to protect reliable downstream water supply. The Arizona Geological Survey documents a separate drawdown hazard along Powell’s sandstone shorelines: reduced confining pressure and retained water pressure can promote rockfalls and dangerous waves.
Geography
Colorado River Basin; Glen Canyon Dam/Lake Powell; Hoover Dam/Lake Mead; Davis Dam/Lake Mohave; Parker Dam/Lake Havasu.
Period
March 2024 engineering guidance; June 2025 completed repairs; May–August 2026 infrastructure assessments and issued 2027–2028 operating rules. July 2022 shoreline geology account and July 2026 dam-safety assessment.
Method
Reclamation’s March 26, 2024 technical memo, pages 6–9, describes cavitation, possible conduit closure and reduced discharge capacity. Its June 18, 2025 completion notice records outlet recoating and continuing cavitation risk. The May 21, 2026 Hoover assessment reports turbine damage exposure and planned replacements. July 2026 Final EIS Technical Appendix 15, pages 15-9–14, distinguishes Hoover’s power and release limits from reduced-flow generation at Davis and Parker. August 2026 Operating Guidelines, section 5.1, establish the Powell protection buffer and coordinated release adjustments. Reclamation’s Parker facility description identifies aqueduct supplies and power reserved for pumping. Appendix R, R-37, provides the current dam-safety interpretation. The Arizona Geological Survey’s July 2022 account describes fractured sandstone shoreline instability during drawdown.
Scope
Power capacity depends on reservoir elevation, flow and available turbines. The 2026 Hoover assessment describes planned turbine replacements; its capacity figures reflect the equipment assessed at that time.
Why it matters
Homestake Creek feeds the Eagle and Colorado rivers. Additional consumptive exports leave less water in this shared system. With low water threatening releases and electricity generation, protecting headwater flows matters to downstream communities, farms and ecosystems.
Section 5.1, printed pages 3–7: Powell infrastructure protection buffer and release adjustments. Sections 5.2–5.3, pages 7–8: federal CRSP operations and 1.25 million acre-feet of annual Lower Basin state reductions for 2027–2028. Section 5.5, pages 12–13: mitigation reserve priorities for federal Tribal settlement duties and resource-dependent shortage offsets.
Across the Whitney-to-Eagle assessment, 36 linked wetland complexes contain 362.1 unique acres of mapped wetland and potential-fen habitat. The lower reach from Blodgett to the Eagle River confluence contains 137.0 of those acres.
Geography
Homestake Creek from the Whitney reservoir reach through Blodgett and Hornsilver to the Eagle River confluence
Period
October 6, 2026 analysis of retained September 18 and October 5 inventory exports; individual source imagery dates preserved
Calculation
The dissolved wetland/potential-fen union is 362.0581 acres in 36 linked complexes. Of this, 49.2262 acres belong to one whole complex crossing the upstream assessment endpoint. The other 35 complexes contain 312.8319 acres. The matched lower-reach subtotal is 137.0329 acres.
Method
Complete CNHP wetland, pond and potential-fen polygons were grouped by mapped contact. Named USGS Homestake Creek links and documented terrain review identify river-linked complexes. Source-feature boundaries stop classification from extending uphill along tributaries. No lateral buffer, elevation cutoff or slope threshold defines the assessment. Areas are dissolved in UTM Zone 13N and divided by 4,046.8564224 square metres per acre. The complex crossing the Whitney upstream endpoint is included whole. Reservoir overlaps are calculated independently against each modeled water surface; linked-complex and inundation totals overlap and are reported separately.
Scope
The acreage measures mapped linked habitat. Timing and severity of drying depend on flow, pond levels and groundwater. The 362.1-acre inventory describes connected wetland complexes in the Whitney-to-Eagle assessment. Each reservoir alternative has a separately reported modeled flood footprint. These inventories overlap. Potential Fen remains the source inventory class. Amber valley-margin complexes remain visible with unresolved connection status.
Why it matters
Water spreads from Homestake Creek through beaver ponds, side channels and shallow groundwater, sustaining connected wetlands across the valley floor. Removing more water can reduce replenishment, lower pond levels and dry habitat that wildlife depends on.
Sources and method
Homestake whole-complex wetland inventory, completed methods and source recordDownload supporting data
Complete methods, classified GeoJSON, complex ledger, source hashes and independently reproduced areas
Groundwater-fed fens are part of hydrologic systems that can supply cool water to connected streams. Trout increasingly use groundwater-fed cool pockets as surrounding water warms. Protecting those connections is increasingly important as heat waves intensify. Regional wetland and beaver studies also document moderated summer temperatures and water storage and release through dry periods.
Geography
U.S. trout studies, Michigan fen research, Oregon and Rocky Mountain wetland studies; Colorado climate assessment
Period
October 8, 2026 synthesis; individual study dates retained
Why it matters
Protecting Homestake's fens, wetland water stores and groundwater connections helps preserve the conditions supporting cold-water habitat through hotter, drier summers.
Measurements from 78 sites in nine Shenandoah watersheds: groundwater moderated stream-temperature sensitivity, with patchy suitable trout habitat. DOI: 10.1890/14-1354.1.
Maintaining wet peat preserves accumulated carbon and soil structure. Colorado restoration research found that disturbed surface peat still differed from reference peat at a site rewetted 20 years earlier.
Geography
Colorado and Wyoming mountain wetlands
Period
October 8, 2026 synthesis; individual study dates retained
Why it matters
Protecting connected water, soil and habitat functions addresses consequences beyond a reservoir shoreline.
The October 8, 2026 whole-basin inventory maps 223.8 acres of emergent and woody wetlands and 15.6 acres of ponds across Fall, Peterson and Resolution creek catchments.
Geography
Whole Fall, Peterson and Resolution creek catchments at their mouths
Period
October 8, 2026 synthesis; individual study dates retained
Scope
Whole-basin mapped resource extent is distinct from project damage acreage.
Why it matters
Protecting connected water, soil and habitat functions addresses consequences beyond a reservoir shoreline.
Sources and method
Fall, Peterson and Resolution: whole-basin wetland inventory and completed methodsDownload supporting data
October 8, 2026 analysis using USFWS wetland polygons and USGS NLDI catchments. Whole-basin resource extent; ponds shown separately.
Flooding organic soils and vegetation can increase carbon dioxide and methane emissions while removing existing plant carbon uptake. A Canadian wetland flooding experiment documented a shift from a carbon sink to a source. Reservoir gases can escape through surface exchange, bubbles and discharged water. The net climate balance compares the new reservoir with the prior landscape, including its natural emissions, carbon uptake and changes in carbon burial.
Geography
Canadian experimental wetland and Eastmain-1 Reservoir; Swiss Alpine reservoir
Period
October 8, 2026 synthesis; study dates and locations retained
Scope
Reservoir fluxes vary with local conditions. Low methane emissions were measured at a Swiss Alpine reservoir. Peat carbon storage and annual net greenhouse-gas exchange are different quantities.
Why it matters
Protecting peat-forming wetlands preserves accumulated carbon and living habitat, while avoiding the additional climate risks associated with impoundment.
Abstract; experimental flooding of a Canadian boreal wetland. Author-hosted abstract: https://researchers.mq.edu.au/en/publications/increases-in-fluxes-of-greenhouse-gases-and-methyl-mercury-follow/
Abstract: Lake Klöntal, Switzerland; low methane emissions relative to most tropical and some temperate reservoirs; no hydroacoustic indication of bubbling.
Organic-matter decomposition consumes dissolved oxygen, while thermal layering can restrict its replenishment in deep water. Early observations at Colorado's Stagecoach Reservoir documented oxygen depletion at depth. At Idaho's Island Park Reservoir, the 2021 drought-year drawdown increased temperature and reduced oxygen, narrowing kokanee habitat. Outlet depth and aeration during release influence the oxygen and temperature of water reaching downstream habitat.
Geography
Colorado, Idaho, Virginia and Lake Powell
Period
October 8, 2026 synthesis; study dates and locations retained
Scope
Reservoir oxygen conditions depend on inflows, mixing, nutrients, season and withdrawal operations. Stagecoach observations describe early impoundment; Island Park observations concern kokanee habitat during a particular drought.
Why it matters
Cold-water habitat depends on both suitable temperatures and enough oxygen. Reservoir storage and releases can change both conditions.
Abstract: deep withdrawal of oxygen-poor water; release aeration and reservoir mixing changed the downstream outcome during the 1996 experimental flood.
Pacific Northwest reservoir studies documented methane pulses during drawdown. Exposed inland-water sediments, including reservoir beds, can emit carbon dioxide. Laboratory experiments found greater phosphorus release after sediment drying, while a Virginia field study linked drawdown with an algal bloom followed by oxygen loss and changing metal concentrations. Repeated exposure and refilling change the chemistry and habitat of a reservoir shoreline.
Geography
Pacific Northwest reservoirs; global exposed-sediment sites; laboratory lake sediments; Virginia
Period
October 8, 2026 synthesis; study dates and locations retained
Scope
A falling-water methane pulse, exposed-bed carbon dioxide flux and reflooding nutrient release are separate processes. Effects depend on sediment properties, moisture, temperature, nutrients and operating history.
Why it matters
A reservoir's ecological costs extend across its operating cycle. Low water adds exposed-bed and habitat concerns after the original wetland has been flooded.
Measurements at exposed inland-water sediments, including reservoirs; controls include moisture, organic matter and temperature. DOI: 10.1038/s41467-020-15929-y.
Microbes can convert existing inorganic mercury into methylmercury, which accumulates in aquatic food webs. Experimental wetland flooding increased methylmercury, and an Oregon reservoir study found greater production in seasonally flooded sediments than in permanently inundated sediments.
Geography
Canadian experimental wetland and Cottage Grove Reservoir, Oregon
Period
October 8, 2026 synthesis; study dates and locations retained
Scope
The Cottage Grove study describes a reservoir receiving mercury from a historic mine.
Why it matters
Flooding and repeated wetting and drying can change contaminant exposure as well as habitat, adding a food-web concern to reservoir operations.
Abstract; experimental flooding of a Canadian boreal wetland. Author-hosted abstract: https://researchers.mq.edu.au/en/publications/increases-in-fluxes-of-greenhouse-gases-and-methyl-mercury-follow/
Whitney would replace wetland habitat within its inundation area. Reservoir research identifies potential added burdens from greenhouse gases, oxygen depletion and water-level cycling. Reservoir releases can also change downstream temperature, chemistry and sediment transport. Additional water removal creates another pathway of impact: a study of 37 Colorado stream reaches found smaller channels and vegetation shifting toward drier-site species below diversions.
Geography
Whitney project concept; Colorado stream and fen studies; reservoir research elsewhere
Period
October 8, 2026 synthesis; study dates and locations retained
Why it matters
The ecological case includes both the functioning landscape lost to flooding and the new pressures on the reservoir and remaining connected habitat downstream.
Abstract; experimental flooding of a Canadian boreal wetland. Author-hosted abstract: https://researchers.mq.edu.au/en/publications/increases-in-fluxes-of-greenhouse-gases-and-methyl-mercury-follow/
Abstract: deep withdrawal of oxygen-poor water; release aeration and reservoir mixing changed the downstream outcome during the 1996 experimental flood.
Reported Fall Creek Dam drawdowns: sediment and organic-matter export, temporary high turbidity and low dissolved oxygen. Deep drawdown setting; accessed October 8, 2026.
The utilities' March 2022 concept links a new lower-valley reservoir, supplied in part from Fall, Peterson and Resolution Creeks, to existing Homestake Reservoir by uphill pumping for delivery to the cities. Whitney would add flooding and water collection to a watershed already exporting water. Research on linked reservoirs shows that effects can interact across the system: a two-reservoir Jinsha River study found accumulating changes to seasonal water temperatures, while fish communities in a Brazilian reservoir chain were associated with combined reservoir volume and spatial connections. The ecological concern for Homestake is the combination of lost wetlands, altered storage and releases, and less water for remaining connected habitat.
Geography
Whitney and Homestake project concept; Jinsha River, China; São Francisco River, Brazil; La Romaine, Québec
Period
October 8, 2026 synthesis; utility concept dated March 2022
Scope
Regional studies of linked reservoirs on the Jinsha and São Francisco rivers, with Québec research on the influence of basin shape, flooded land and climate. Responses differ by process. In the Jinsha study, most flow alteration came from the larger upstream reservoir. In Québec, basin shape, flooded land and climate mattered more for surface-water CO2 and methane concentrations than position in the reservoir chain. The Québec measurements describe gas concentrations in surface water.
Why it matters
Protecting Homestake avoids adding a flooded valley and new water collection to an already altered watershed, preserving the wetlands and water connections on which remaining habitat depends.
Abstract and conclusions: Xiluodu and Xiangjiaba reservoirs. Both altered the seasonal temperature cycle; flow alteration was largely attributable to the larger upstream reservoir. Publisher text: https://www.mdpi.com/2073-4441/11/5/1008/xml
Abstract: São Francisco River, Brazil; spatial variables and cumulative reservoir volume were the strongest tested predictors for fish communities. Author university record: https://recerca.udg.edu/en/publications/cumulative-ecological-effects-of-a-neotropical-reservoir-cascade-/
Abstract: three La Romaine reservoirs, Québec. Basin shape, pre-flood land cover and climate were main drivers of surface-water gas concentrations; position in the cascade played a minor role. Abstract: https://pubmed.ncbi.nlm.nih.gov/34952047/
Save Homestake assesses Compact exposure as serious and increasing under sustained drought. July 2026 preliminary federal modeling for anticipated 2027–2028 rules shows ten-year Lee Ferry flow below 75 million acre-feet only in critically dry outliers; conditional medians remain above 75. The longer 2027–2060 Representative Preferred analysis has a critically dry median of 73.9 million acre-feet. These are conditional scenario results, not breach probabilities. An October 6 original policy analysis estimates approximately 81.2 million acre-feet for the ten years ending September 2026. The authors explain that Mexico-sharing interpretations could expose the Upper Division to a deficit while the Upper Division asserts compliance. Article III(d) prohibits the Upper Division from causing depletion below 75 million acre-feet; causation and other Compact obligations matter to legal enforcement. Continued drought and protective restrictions on reservoir releases narrow the margin for additional consumption.
Geography
Colorado River Basin; Lee Ferry; Western Slope and Front Range diversions
Period
July 2026 conditional modeling: 2027–2028 and 2027–2060; October 6, 2026 policy analysis of the ten years ending September 2026.
Method
Appendix T, T-16 and T-50, reports 2027–2028 conditional ten-year-flow medians of 80.5 million acre-feet (Average), 78.2 (Dry) and 78.8 (Critically Dry); the critically dry minimum is 73.7. Technical Appendix 3, 3-54–3-55, reports long-horizon Dry median 76.4 and Critically Dry median 73.9. Both use non-probabilistic Decision Making under Deep Uncertainty, grouping model-year results by preceding three-year naturalized flow. Long-horizon results pool 2027–2060 across 400 futures; the operating framework ends in 2036. The October 6 authors’ approximate 81.2 figure is attributed to their research. Appendix R leaves competing Compact interpretations unresolved.
Scope
The July two-year analysis anticipates rules issued in August and is not an October forecast. Conditional distributions do not yield a probability of breach by 2036 or a probability of Whitney curtailment. An actual or modeled flow crossing is distinct from a finding that the Upper Division caused unlawful depletion. The 82.5 million acre-foot benchmark represents a disputed Mexico-sharing interpretation, with actual treaty reductions and accounting relevant to the amount; it is not a universally settled threshold. The qualitative risk rating is Save Homestake’s inference from the dated evidence.
Why it matters
Additional consumptive exports reduce the water available within a system already balancing declining reserves, downstream obligations and infrastructure protection. Whitney’s long-lived investment and permanent valley impacts would depend on water whose physical availability and lawful use are increasingly contested.
Articles II(a), II(f), III(c)–(d), IV(c), VII and IX: river-system/out-of-basin service definitions; Mexico deficiency sharing; 75 million acre-foot ten-year non-depletion provision; state administration, Tribal obligations and enforcement rights retained.
Articles IV and VIII(d)(8): Commission findings on necessary curtailment and state shares; Article XV(b): state administration of available apportioned water; Article XIX: federal Tribal/treaty rights retained.
Printed T-8–T-9: non-probabilistic analysis of 400 plausible futures; T-16 and Table T-12, T-50: conditional ten-year Lee Ferry flow medians and critically dry outliers for 2027–2028. July analysis precedes the issued August rules.
Printed 3-19–3-20: non-probabilistic model analysis over 2027–2060, distinct from the framework ending 2036. Printed 3-54–3-55: Representative Preferred conditional ten-year Lee Ferry volumes, including critically dry median 73.9 million acre-feet.
Printed pages 2–3 and footnote 1: approximately 81.2 million acre-feet at Lee Ferry as of October 1 and competing Mexico-sharing interpretations; Upper Division asserts compliance. Page 10: transfers from upstream reservoirs buy time but create no new water. Pages 34–35: structural supply imbalance and litigation exposure. This is original policy research, rather than an official compliance determination.
Section 5.1, printed pages 3–7: Powell infrastructure protection buffer and release adjustments. Sections 5.2–5.3, pages 7–8: federal CRSP operations and 1.25 million acre-feet of annual Lower Basin state reductions for 2027–2028. Section 5.5, pages 12–13: mitigation reserve priorities for federal Tribal settlement duties and resource-dependent shortage offsets.
Interior already operates major federal reservoirs and manages Lower Basin mainstream delivery shortages. Its issued 2027–2028 rules impose 1.25 million acre-feet of annual Lower Basin state reductions. Mexico accepted 250,000 acre-feet of annual reductions for 2027–2028 under September 2026 Minute 334. A federal mitigation reserve prioritizes specified Tribal settlement delivery duties; further offsets depend on available resources. The August Record of Decision preserves state apportionments, Upper Basin obligations, Tribal rights and judicial remedies. Necessary Upper Basin curtailment involves the Upper Colorado River Commission’s interstate determinations and state administration; Colorado’s State Engineer has statutory Compact-compliance duties. Nevada filed a federal challenge to the operating decision on August 24, 2026. On October 27, the Central Arizona Water Conservation District, which operates the Central Arizona Project, asked to join Nevada’s case. Its proposed complaint challenges the distribution of shortages and releases from upstream reservoirs. As of November 2, 2026, no ruling on its motion had been verified.
Geography
Colorado River Basin; Lee Ferry; Western Slope and Front Range diversions
Period
1944 Treaty; 1948 Compact; 2006 decree; August–September 2026 issued rules and international agreement; October 2026 CRS report; Colorado statutes 2026. Litigation status checked November 2, 2026.
Method
Operating Guidelines sections 5.2–5.3 permit federal reservoir and Lower Basin delivery decisions under existing law if implementing agreements are absent. Section 5.5 prioritizes federal settlement firming/delivery obligations in the mitigation reserve, then specified Tribal shortage offsets. The 2006 decree II(B)(3) supplies Lower Basin shortage authority subject to protected rights, consultation and statutes. Treaty Article 10 sets Mexico’s normal annual 1.5 million acre-foot allocation and drought reduction provision; IBWC’s September 9 release confirms Minute 334. ROD 10.10–10.11 retains apportionments and legal claims. Upper Basin Compact IV/VIII and Colorado section 37-80-104 govern interstate determinations and Colorado administration. CRS footnote 135 distinguishes Lower Basin water-master authority from debated Upper Basin limits. Nevada’s August 24, 2026 release documents the filing of its challenge. The district’s motion and proposed complaint were filed October 27 as ECF 35 and 35-7. The November 2 court feed identifies ECF 51 as a proceeding about counsel’s admission to practice.
Scope
Federal reservoir operations, Lower Basin delivery contracts, international agreements and Colorado water-right administration have distinct legal foundations. Mandatory Lower Basin reductions and Upper Basin Compact-compliance administration follow separate legal processes. Federal mitigation reserve offsets depend on available resources. Contested powers or obligations may require judicial resolution.
Why it matters
For Western Slope exports, the material risk is tighter operations, reduced physical supply, litigation and possible curtailment of affected rights. The shared river must sustain communities, farms, Tribal deliveries, Mexico and ecosystems while maintaining critical infrastructure. Building additional export capacity creates no additional water and exposes its promised yield to these competing pressures.
Section 5.1, printed pages 3–7: Powell infrastructure protection buffer and release adjustments. Sections 5.2–5.3, pages 7–8: federal CRSP operations and 1.25 million acre-feet of annual Lower Basin state reductions for 2027–2028. Section 5.5, pages 12–13: mitigation reserve priorities for federal Tribal settlement duties and resource-dependent shortage offsets.
Printed pages 27, 29–30: operating framework, consultation and emergency authority. Sections 10.10–10.11, pages 37–38: state apportionments, Upper Basin obligations, Tribal rights and judicial remedies retained; general intrastate water distribution is outside the guidelines.
Article II(B)(3), 547 U.S. 155–156, PDF pages 5–6: Secretary apportions insufficient Lower Basin mainstream supply after protecting present perfected rights and consultation, consistently with federal statutes. Article VIII(D) preserves Compact interpretation; Article IX retains Court jurisdiction.
Article 10(a)–(b), PDF pages 21–22: 1.5 million acre-feet annual Colorado River allocation to Mexico; extraordinary drought or serious U.S. irrigation-system accident permits proportional reductions.
Pages 1–2: Minute 334 signed September 2 and approved by both governments; extends/replaces measures in Minutes 323/330. Mexico accepts 250,000 acre-feet of annual reductions in 2027–2028, with consultation if conditions worsen.
Articles IV and VIII(d)(8): Commission findings on necessary curtailment and state shares; Article XV(b): state administration of available apportioned water; Article XIX: federal Tribal/treaty rights retained.
Section 37-80-104, printed/PDF page 826: State Engineer makes and enforces regulations needed to meet Colorado Compact commitments, with legal and equitable administration among appropriators obligated to curtail. Official 2026 compilation.
Footnote 135: Secretary is the Lower Basin water master; no comparable designation or authority in the Upper Basin, where authority limits remain debated. This link reproduces the CRS report.
Official announcement of filing by Nevada, its Colorado River Commission and Southern Nevada Water Authority challenging the August Record of Decision. Filing is an event; the announcement’s allegations are the plaintiffs’ positions.
CNHP’s September 12, 2011 field surveys confirmed two groundwater-fed fens near Gold Park in Homestake Valley. Peat measured 92 cm at site 6982 and 88 cm at site 6969. Both sites had saturated peat, wetland plant communities, no recorded disturbance and no recorded noxious weeds.
Geography
Two CNHP Gold Park survey sites in Homestake Valley, White River National Forest
Period
Field surveys September 12, 2011; report November 2011
Method
CNHP field identification of fens, peat-depth measurements, descriptions of saturated soils and groundwater inflow, plant-community records, and disturbance and noxious-weed observations.
Scope
The condition baseline is dated September 12, 2011 at the two surveyed sites.
Why it matters
Together, the deep saturated peat, established wetland vegetation and absence of recorded disturbance provide affirmative evidence of healthy, functioning fen ecosystems at the surveyed sites in 2011. Protecting these established ecosystems means protecting the groundwater supplies and ecological conditions that sustain them.
CNHP’s Fens2025V2 inventory identifies 15 Confirmed Fen polygons within the Homestake Creek watershed. The interactive valley map distinguishes those confirmed polygons from Potential Fen and displays the broader map’s Confirmed Peat-Accumulating Wetland class separately.
Geography
Homestake Creek watershed at the Eagle River confluence, USGS NLDI basin COMID 1320344; interactive map also covers surrounding terrain
Period
CNHP Fens2025V2 inventory retrieved October 10, 2026
Method
Official CNHP Fens2025V2 polygons were intersected with the Homestake outlet watershed from USGS NLDI. Fifteen Confirmed Fen and 160 Potential Fen polygons fall within the watershed. Polygon counts describe inventory features; the two 2011 Gold Park survey sites lie within one confirmed polygon. A separate comparison with the stored modeled A–D full-pool boundaries finds no intersections with the current V2 fen polygons. Published potential-fen overlap figures use the September 18, 2026 inventory; mapped wetlands also overlap the pools.
Scope
The current and September 18 fen inventories differ in mapped coverage. This comparison describes the inventory versions, rather than a field finding that wetlands or groundwater effects are absent.
Why it matters
The watershed contains documented fen habitat whose water sources and ecological functions belong in the conservation case. Displaying confirmed polygons clearly, alongside the dated 2011 condition baseline and the separate reservoir-overlap inventory, makes that evidence easier to see and assess.
Sources and method
Colorado Natural Heritage Program, Fens (CNHP 2025), Fens_2025_V2 map service
Documentation that prior to site disturbance for the Project the applicant will have obtained all necessary property rights, permits and approvals. The Board may, at its discretion, defer making a final decision on the application until outstanding property rights, permits and approvals are obtained.
Geography
Eagle County
Period
Chapter VI before the October 27 vote. October 27 approved package compared November 2, 2026.
Scope
The passage above reproduces Chapter VI. October 27 comparison: §404, PDF p. 43.
Why it matters
All necessary rights, permits and approvals must be obtained before disturbance. The Board may defer a decision while any remain outstanding.
The Project will not have a significant adverse effect on the capability of local governments affected by the Project to provide services, or exceed the capacity of service delivery systems.
Geography
Eagle County
Period
Chapter VI before the October 27 vote. October 27 approved package compared November 2, 2026.
Scope
The passage above reproduces Chapter VI. October 27 comparison: §419, PDF p. 47.
Why it matters
The standard protects both the capacity of local service systems and governments’ ability to serve residents now and in the future.
The planning, design and operation of the Project shall reflect principals of resource conservation, energy efficiency and recycling or reuse.
Geography
Eagle County
Period
Chapter VI before the October 27 vote. October 27 approved package compared November 2, 2026.
Scope
The passage above reproduces Chapter VI. October 27 comparison: §§331(A)(3), 331(E) and 434(D), PDF pp. 38, 40 and 50.
Why it matters
The water-project provisions address conservation techniques and efficient use, including recycling and reuse. Their focus is narrower than Chapter VI’s general resource and energy criterion.
The Project will not significantly degrade surface water quality.
Geography
Eagle County
Period
Chapter VI before the October 27 vote. October 27 approved package compared November 2, 2026.
Scope
The passage above reproduces Chapter VI. October 27 comparison: §§307(D) and 406(C)(1), PDF pp. 24–25 and 43–44.
Why it matters
The watershed standard connects streamflow, hydrology and water quality. It addresses stream uses, pollutants, erosion and the shape of the hydrograph.
The Project will not significantly degrade wetlands, and riparian areas.
Geography
Eagle County
Period
Chapter VI before the October 27 vote. October 27 approved package compared November 2, 2026.
Scope
The passage above reproduces Chapter VI. October 27 comparison: §§307(F) and 406(C)(3), PDF pp. 26–27 and 44.
Why it matters
The package expressly names fens and protects wetland structure, function, filtering and extent. Those functions depend on the valley floor’s water supply.
The benefits accruing to the County and its citizens from the Project outweigh the losses of any natural, agricultural, recreational, grazing, commercial or industrial resources within the County, or the losses of opportunities to develop such resources.
Geography
Eagle County
Period
Chapter VI before the October 27 vote. October 27 approved package compared November 2, 2026.
Scope
The passage above reproduces Chapter VI. October 27 comparison: Article 4, §§401–435, PDF pp. 43–51.
Why it matters
Chapter VI weighs county benefits against local resource losses. Article 4 of the October package contains no equivalent standalone balancing standard.
The Project shall be necessary to meet community development and population demands in the areas to be served by the Project.
Geography
Eagle County
Period
Chapter VI before the October 27 vote. October 27 approved package compared November 2, 2026.
Scope
The passage above reproduces Chapter VI. October 27 comparison: §§303(D), 331(B) and 434(A)–(B), PDF pp. 21, 39 and 49–50.
Why it matters
The application must address demand and the basis for its projections in the area served. The growth and facility tests in §434(A)–(B) apply to projects serving the county. Article 4 omits a standalone necessity test.
Urban development, population densities, and site layout and design of storm water and sanitation systems shall be accomplished in a manner that will prevent the pollution of aquifer recharge areas.
Geography
Eagle County
Period
Chapter VI before the October 27 vote. October 27 approved package compared November 2, 2026.
Scope
The passage above reproduces Chapter VI. October 27 comparison: §407, PDF p. 45.
Why it matters
The standard addresses aquifer recharge pollution from urban development and population increases associated with the project.
