Hydrohistorian
Water that crosses the divide
The tunnels and high ditches that move water out of one Colorado river basin and into another — hand-curated, with the gaged record wherever DWR meters a portal. Why these records are ledgers rather than rivers is a lesson of its own.
Each dot is a gaged portal; a dashed line joins the two portals of one facility where both are metered. Click a dot for its gage page.
Alva B. Adams Tunnel
Tunnel · Northern Water / USBR (Colorado-Big Thompson)
Colorado River headwaters at Grand Lake (Div 5) → Big Thompson River at Estes Park (Div 1)
Alva B. Adams Tunnel at East Portal near Estes Park
(ADATUNCO · record 1947–2026 · latest cached 461.0 cfs)
· live at DWR ↗
Adams Tunnel at East Portal-Computed Flow
(ADANETCO · record 1996–2025 · latest cached 219.0 cfs)
· live at DWR ↗
Moffat Water Tunnel
Tunnel · Denver Water
Fraser River collection system (Div 5) → South Boulder Creek (Div 1)
Moffat Water Tunnel at East Portal (MOFTUNCO · record 1936–2026 · latest cached 30.4 cfs) · live at DWR ↗
Harold D. Roberts Tunnel
Tunnel · Denver Water
Blue River at Dillon Reservoir (Div 5) → North Fork South Platte River near Grant (Div 1)
Roberts Tunnel at East Portal near Grant (ROBTUNCO · record 1963–2026 · latest cached 220.0 cfs) · live at DWR ↗
August P. Gumlick Tunnel
Tunnel · Denver Water
Williams Fork headwaters at Jones Pass (Div 5) → West Fork Clear Creek (Div 1)
August P. Gumlick Tunnel near Jones Pass (APGTUNCO · record 1940–1999 · latest cached 0.0 cfs) · live at DWR ↗
Vasquez Tunnel
Tunnel · Denver Water
West Fork Clear Creek (Div 1) → Vasquez Creek, Fraser basin (Div 5)
No cached gage record for this facility.
Charles H. Boustead Tunnel
Tunnel · Southeastern Colorado WCD / USBR (Fryingpan-Arkansas)
Fryingpan River and Hunter Creek collection (Div 5) → Turquoise Lake, Arkansas River basin (Div 2)
Charles H. Boustead Tunnel (BOUTUNCO · record 1971–2026 · latest cached 3.8 cfs) · live at DWR ↗
Busk-Ivanhoe Tunnel
Tunnel · Pueblo Board of Water Works & Aurora Water (Busk-Ivanhoe system)
Ivanhoe, Lyle, Hidden Lake and Pan Creeks, Fryingpan basin (Div 5) → Busk Creek to Turquoise Lake, Arkansas basin (Div 2)
Busk-Ivanhoe Tunnel (BUSTUNCO · record 1948–2026 · latest cached 0.4 cfs) · live at DWR ↗
Homestake Tunnel
Tunnel · Colorado Springs Utilities / Aurora Water
Homestake Creek, Eagle River basin (Div 5) → Turquoise Lake, Arkansas River basin (Div 2)
Homestake Tunnel (HOMTUNCO · record 1966–2026 · latest cached 0.0 cfs) · live at DWR ↗
Twin Lakes Tunnel
Tunnel · Twin Lakes Reservoir & Canal Co.
Roaring Fork headwaters at Independence Pass (Div 5) → Lake Creek to Twin Lakes, Arkansas basin (Div 2)
Twin Lakes Tunnel (TWITUNCO · record 1935–2026 · latest cached 10.9 cfs) · live at DWR ↗
Ewing Ditch
Ditch · Pueblo Board of Water Works
Piney Creek, Eagle River headwaters at Tennessee Pass (Div 5) → Tennessee Creek, Arkansas basin (Div 2)
Ewing Ditch at Tennessee Pass
(EWIDITCO · record 1947–2026 · latest cached 0.0 cfs)
· live at DWR ↗
Ewing Ditch Bypass
(EWIDBPCO · record 2026–2026 · latest cached 0.4 cfs)
· live at DWR ↗
Wurtz Ditch
Ditch · Pueblo Board of Water Works
Eagle River headwaters at Tennessee Pass (Div 5) → Tennessee Creek, Arkansas basin (Div 2)
Wurtz Ditch near Tennessee Pass
(WURDITCO · record 1947–2026 · latest cached 0.0 cfs)
· live at DWR ↗
Wurtz Extension
(WUREXTCO · record 1991–2026 · latest cached 0.0 cfs)
· live at DWR ↗
Wurtz Extension Ditch near Tennessee Pass
(WUREXDCO · record 1967–1990 · latest cached 0.0 cfs)
· live at DWR ↗
Columbine Ditch (Fremont Pass)
Ditch · Pueblo Board of Water Works
East Fork Eagle River at Fremont Pass (Div 5) → Chalk Creek, Arkansas basin (Div 2)
Columbine Ditch near Fremont Pass (COLDITCO · record 1947–2026 · latest cached 0.0 cfs) · live at DWR ↗
Hoosier Pass Tunnel
Tunnel · Colorado Springs Utilities (Continental-Hoosier project)
Blue River headwaters (Div 5) → Montgomery Reservoir, Middle Fork South Platte (Div 1)
Hoosier Pass Tunnel at Montgomery Reservoir near Alma
(HSPTUNCO · record 1953–2026 · latest cached 0.2 cfs)
· live at DWR ↗
Bemrose-Hoosier Diversion near Hoosier Pass
(BEMHODCO · record 1957–2026 · latest cached 0.1 cfs)
· live at DWR ↗
Monte Cristo Diversion near Hoosier Pass
(MONTDOCO · record 1957–2025 · latest cached 0.0 cfs)
· live at DWR ↗
McCullough-Sp-Crys-Diversion near Hoosier Pass
(MCCDIVCO · record 1954–2025 · latest cached 0.0 cfs)
· live at DWR ↗
Vidler Tunnel
Tunnel
Peru Creek, Snake River basin (Div 5) → Clear Creek headwaters near Argentine Pass (Div 1)
Vidler Tunnel near Argentine Pass
(VIDTUNCO · record 1970–2026 · latest cached 0.0 cfs)
· live at DWR ↗
Vidler Tunnel, West Portal
(VIDLERCO · record 1998–1998 · latest cached 8.5 cfs)
· live at DWR ↗
Berthoud Pass Ditch
Ditch
Fraser River headwaters at Berthoud Pass (Div 5) → West Fork Clear Creek (Div 1)
Berthoud Pass Ditch at Berthoud Pass (BERDITCO · record 1932–2026 · latest cached 0.2 cfs) · live at DWR ↗
Grand River Ditch
Ditch · Water Supply & Storage Co.
Colorado River headwaters at La Poudre Pass (Div 5) → Cache la Poudre River via Long Draw (Div 1)
Grand River Ditch at La Poudre Pass (GRNDRDCO · record 1929–2026 · latest cached 7.1 cfs) · live at DWR ↗
Laramie-Poudre Tunnel
Tunnel · Water Supply & Storage Co.
Laramie River (Div 1, WD 48) → Cache la Poudre River (Div 1, WD 3)
Laramie Poudre Tunnel @ 10 Ft Parshall Flume (LAPTUNCO · record 1931–2026 · latest cached 20.1 cfs) · live at DWR ↗
Skyline Ditch
Ditch · Water Supply & Storage Co.
Laramie River headwaters (Div 1, WD 48) → Chambers Lake, Cache la Poudre (Div 1, WD 3)
Skyline Ditch at Chambers Lake (SKYDCLCO · record 1922–2025 · latest cached 0.0 cfs) · live at DWR ↗
Columbine Ditch (Deadman Hill)
Ditch · Water Supply & Storage Co.
Laramie River basin at Deadman Hill (Div 1, WD 48) → Cache la Poudre River (Div 1, WD 3)
Columbine Ditch at Deadman Hill (COLDEDCO · record 1940–2024 · latest cached 0.0 cfs) · live at DWR ↗
Wilson Supply Ditch
Ditch
Sand Creek, Laramie River basin (Div 1, WD 76) → North Fork Cache la Poudre (Div 1, WD 3)
Wilson Supply Ditch near Eaton Reservoir @ 10 Ft Parshall Flume (WSDEARCO · record 1933–2026 · latest cached 0.0 cfs) · live at DWR ↗
Michigan Ditch
Ditch · City of Fort Collins
Michigan River, North Platte basin at Cameron Pass (Div 6) → Joe Wright Creek, Cache la Poudre (Div 1)
Michigan Ditch at Cameron Pass (MICDCPCO · record 1932–2026 · latest cached 0.0 cfs) · live at DWR ↗
Cameron Pass Ditch
Ditch
North Platte basin at Cameron Pass (Div 6) → Joe Wright Creek, Cache la Poudre (Div 1)
Cameron Pass Ditch near Cameron Pass (CAPDCPCO · record 1931–2026 · latest cached 0.0 cfs) · live at DWR ↗
Dolores Tunnel
Tunnel · Montezuma Valley Irrigation Co. / USBR (Dolores Project)
Dolores River at McPhee Reservoir (Div 7, WD 71) → Montezuma Valley, McElmo Creek basin (Div 7, WD 32)
Dolores Tunnel Outlet near Dolores (DOLTUNCO · record 1985–2026 · latest cached 226.0 cfs) · live at DWR ↗
Gunnison Tunnel
Tunnel · Uncompahgre Valley Water Users Assn. / USBR
Gunnison River in the Black Canyon (Div 4, WD 62) → Uncompahgre Valley via the South Canal (Div 4, WD 68)
Gunnison River below Gunnison Tunnel (GUNBEPCO · record 1910–2026 · latest cached 445.0 cfs) · live at DWR ↗
Azotea Tunnel (San Juan-Chama Project)
Tunnel · USBR
Navajo, Little Navajo and Rio Blanco headwaters (Div 7) → Rio Grande basin at Chama, New Mexico
Azotea Tunnel Outlet near Chama, Nm
(AZOTUNNM · record 1985–2026 · latest cached 0.0 cfs)
· live at DWR ↗
Oso Diversion near Chromo
(OSODIVCO · record 1991–2026 · latest cached 0.0 cfs)
· live at DWR ↗
Little Oso Diversion near Chromo
(LOSODVCO · record 1993–2026 · latest cached 0.0 cfs)
· live at DWR ↗
Blanco Diversion near Pagosa Springs
(BLADIVCO · record 1991–2026 · latest cached 0.0 cfs)
· live at DWR ↗
Weminuche Pass Ditch
Ditch
Weminuche Creek, San Juan basin (Div 7) → Rio Grande headwaters at Weminuche Pass (Div 3)
Weminuche Pass Ditch at Weminuche Pass (WEMDITCO · record 1948–2026 · latest cached 0.0 cfs) · live at DWR ↗
Pine River-Weminuche Pass Ditch
Ditch
Pine River headwaters, San Juan basin (Div 7) → Rio Grande headwaters at Weminuche Pass (Div 3)
Pine River Weminuche Pass Ditch at Weminuche Pass (PRWDITCO · record 1948–2026 · latest cached 0.0 cfs) · live at DWR ↗
Williams Creek-Squaw Pass Ditch
Ditch
Williams Creek, San Juan basin (Div 7) → Squaw Creek, Rio Grande basin (Div 3)
William's Creek-Squaw Pass Ditch at Grizzly Pass (WCSDITCO · record 1948–2026 · latest cached 0.0 cfs) · live at DWR ↗
Don La Font Ditches
Ditch
Piedra River headwaters at Piedra Pass (Div 7) → Rio Grande headwaters (Div 3)
Don La Font Ditch No. 1 at Piedra Pass
(DLFDT1CO · record 1951–2025 · latest cached 0.0 cfs)
· live at DWR ↗
Don La Font Ditch No. 2 at Piedra Pass
(DLFDT2CO · record 1962–2026 · latest cached 0.2 cfs)
· live at DWR ↗
Don La Font Ditch at Piedra Pass (Combined)
(DLFCMBCO · record 1990–2023 · latest cached 0.0 cfs)
· live at DWR ↗
Treasure Pass Ditch
Ditch
Wolf Creek, San Juan basin at Wolf Creek Pass (Div 7) → Rio Grande basin (Div 3)
Treasure Pass Ditch at Wolf Creek Pass (TREDITCO · record 1948–2026 · latest cached 0.0 cfs) · live at DWR ↗
Tarbell Ditch
Ditch
Cochetopa Creek, Gunnison basin at Cochetopa Pass (Div 4) → Saguache Creek, Rio Grande basin (Div 3)
Tarbell Ditch near Cochetopa Pass (TARBELCO · record 1949–2026 · latest cached 1.5 cfs) · live at DWR ↗
How this list is curated
Facilities enter this registry by hand, from public record — never inferred from names, because “tunnel” also belongs to mine drainage and municipal pipelines. Candidates are nominated by name tokens, by transmountain-export decreed uses in the water-rights record, and by basin configurations; each is confirmed before it appears here. Gage readings are the weekly-refreshed cache, never fetched live — the DWR link beside each record is the live source.