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Active Dam Release Warnings
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Dillon Dam release — elevated flows on Blue River / Snake River
Current flow: 365 CFS
at Blue River below Green Mountain Reservoir
Expect water levels to remain elevated for 12–24h below Dillon Dam. Check current USGS gauge before entering.
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Ruedi Dam release — elevated flows on Frying Pan River
Current flow: 712 CFS
at Frying Pan River near Ruedi
Expect water levels to remain elevated for 12–24h below Ruedi Dam. Check current USGS gauge before entering.
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Low-Head Dam Danger Zones
Low-head dams are among the most deadly hydraulic features in moving water. The recirculating hydraulic traps victims regardless of swimming ability. MANDATORY PORTAGE.
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DANGER: Low-Head Dam — Cal Gulch Diversion Dam
South Platte River · CO
Hydraulic Recirculation Zone — Extremely Dangerous
Low-head dams create a submerged recirculating hydraulic (keeper hole) that traps swimmers, kayakers, and rafters. Even experienced paddlers have drowned. ALWAYS portage around this structure — do not attempt to run it.
Urban stretch — popular kayak run; hydraulic keeper at all flows above 200 CFS
📍 39.7480, -105.0240
⚠️ Hazard zone: 400 ft upstream + 300 ft downstream
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DANGER: Low-Head Dam — Globeville Diversion Dam
South Platte River · CO
Hydraulic Recirculation Zone — Extremely Dangerous
Low-head dams create a submerged recirculating hydraulic (keeper hole) that traps swimmers, kayakers, and rafters. Even experienced paddlers have drowned. ALWAYS portage around this structure — do not attempt to run it.
Denver Metro — often missed by paddlers unfamiliar with the stretch; no warning signage historically
📍 39.7810, -104.9950
⚠️ Hazard zone: 400 ft upstream + 300 ft downstream
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DANGER: Low-Head Dam — Windsor Diversion Dam
Cache la Poudre River · CO
Hydraulic Recirculation Zone — Extremely Dangerous
Low-head dams create a submerged recirculating hydraulic (keeper hole) that traps swimmers, kayakers, and rafters. Even experienced paddlers have drowned. ALWAYS portage around this structure — do not attempt to run it.
Below the Poudre Canyon — high spring flows from Horsetooth releases; extremely dangerous May–July
📍 40.4759, -104.9050
⚠️ Hazard zone: 500 ft upstream + 400 ft downstream
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DANGER: Low-Head Dam — Boulder Creek Diversion Structure
Boulder Creek · CO
Hydraulic Recirculation Zone — Extremely Dangerous
Low-head dams create a submerged recirculating hydraulic (keeper hole) that traps swimmers, kayakers, and rafters. Even experienced paddlers have drowned. ALWAYS portage around this structure — do not attempt to run it.
Boulder Creek Path recreation area — tubers frequently unaware; fatal hydraulic at flows >100 CFS
📍 40.0070, -105.2610
⚠️ Hazard zone: 300 ft upstream + 250 ft downstream
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DANGER: Low-Head Dam — Clear Creek Diversion at Golden
Clear Creek · CO
Hydraulic Recirculation Zone — Extremely Dangerous
Low-head dams create a submerged recirculating hydraulic (keeper hole) that traps swimmers, kayakers, and rafters. Even experienced paddlers have drowned. ALWAYS portage around this structure — do not attempt to run it.
Whitewater park upstream; diversion structure immediately below — several drownings on record
📍 39.7550, -105.2240
⚠️ Hazard zone: 350 ft upstream + 300 ft downstream
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DANGER: Low-Head Dam — Canon City Diversion Dam
Arkansas River · CO
Hydraulic Recirculation Zone — Extremely Dangerous
Low-head dams create a submerged recirculating hydraulic (keeper hole) that traps swimmers, kayakers, and rafters. Even experienced paddlers have drowned. ALWAYS portage around this structure — do not attempt to run it.
Royal Gorge run take-out area; high spring flows from Pueblo Reservoir releases
📍 38.4410, -105.2340
⚠️ Hazard zone: 500 ft upstream + 400 ft downstream
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DANGER: Low-Head Dam — Gunnison River Diversion at Delta
Gunnison River · CO
Hydraulic Recirculation Zone — Extremely Dangerous
Low-head dams create a submerged recirculating hydraulic (keeper hole) that traps swimmers, kayakers, and rafters. Even experienced paddlers have drowned. ALWAYS portage around this structure — do not attempt to run it.
High runoff season; floaters should portage
📍 38.7409, -108.0774
⚠️ Hazard zone: 450 ft upstream + 350 ft downstream
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Reservoir Levels & Access
Storage levels, boat ramp access, and downstream surge risk from BOR + USACE data.
Blue Mesa Reservoir
Blue Mesa Dam · Gunnison River
❓ No data
fishingboatingcamping
Largest reservoir in CO. Elk Creek, Lake Fork, Cimarron marinas.
📡 Downstream gauge: USGS 09128000
Live level data unavailable — BOR API
Dillon Reservoir
Dillon Dam · Blue River / Snake River
❓ No data
sailingkayakingfishing
Summit County. Denver Water operated. Blue River below dam is top Gold Medal fishery.
📡 Downstream gauge: USGS 09058000
Live level data unavailable — BOR API
Green Mountain Reservoir
Green Mountain Dam · Blue River
❓ No data
fishingboatingcamping
Summit County. Kokanee salmon + rainbow trout. Heeney marina.
📡 Downstream gauge: USGS 09057500
Live level data unavailable — BOR API
Ruedi Reservoir
Ruedi Dam · Frying Pan River
❓ No data
fishingboatingcamping
Frying Pan tailwater downstream is world-class Gold Medal trout fishery.
📡 Downstream gauge: USGS 09081600
Live level data unavailable — BOR API
Pueblo Reservoir
Pueblo Dam · Arkansas River
❓ No data
fishingboatingwater skiingcamping
Freeport-area marina; significant releases affect Royal Gorge whitewater below
📡 Downstream gauge: USGS 07099970
Live level data unavailable — BOR API
Chatfield Reservoir
Chatfield Dam · South Platte River
❓ No data
boatingfishingcampingswimming
Denver Metro. Releases directly affect South Platte fishing corridor.
📡 Downstream gauge: USGS 06701900
Live level data unavailable — BOR API
Horsetooth Reservoir
Horsetooth Dam · Inlet canals (C-BT project)
❓ No data
boatingfishingcampingswimming
Fort Collins. Outlet releases feed Cache la Poudre Canyon flows.
Live level data unavailable — BOR API
📡 Data Sources
- Low-head dam database: USACE National Inventory of Dams (NID) + CO Dam Safety Branch + MT DNRC
- Reservoir levels: Bureau of Reclamation (BOR) RISE API — updated hourly
- Downstream flow: USGS National Water Information System — 30 min
- Surge warnings: Cross-reference BOR release data × USGS downstream gauges