About this project
State parks sometimes keep a diorama near the visitor center: a painted relief of the landscape, with a ribbon of blue resin showing how water moves through it, over this divide, into that reservoir, out through a canal to somewhere far away. People stand in front of them longer than they stand at any signboard. Drive across Colorado in a dry year and the reservoirs make the same point with no label at all: a bathtub ring of pale rock where the water normally sits.
This site is that diorama for the whole state, with real numbers that update daily.
Most of Colorado's people live east of the Continental Divide. Most of its water starts on the west side. The figure usually quoted is that about 80% of the state's streamflow originates west of the Divide, while close to nine in ten Coloradans live east of it. Tunnels under the Divide close the gap, taking water from the Colorado River's headwaters and delivering it east.
When Denver turns on a tap, some of that water started as snow above Winter Park and rode the Moffat Tunnel under James Peak; some was Blue River water released from Dillon Reservoir through the 23-mile Roberts Tunnel. Fort Collins and the northern Front Range drink Lake Granby water delivered by the Colorado–Big Thompson Project's Adams Tunnel. Pueblo, Colorado Springs and the Arkansas Valley draw on the Fryingpan–Arkansas Project, which moves Fryingpan headwaters under the Divide into Turquoise Lake and Twin Lakes. On the map, those tunnels are the dashed ribbons crossing the dotted line. On the flow view you can watch each city's water blend from its sources.
This is why a dry winter over Winter Park shows up in a Denver watering schedule. The Divide decides where the water falls. The tunnels decide who gets it.
Every reservoir is drawn as a glass of water, wide at the rim and narrow at the base, like the cross-section of a canyon filling up. The size of the glass is its total capacity. The color inside is the water's source: each headwater has its own hue, and blends stay traceable. The level is current storage, filled by area, so a glass that looks half full holds half its capacity, the same way a tapering reservoir stores less water per foot near the bottom. The bone-colored tick is where the level would sit in a normal year. The drought is the gap between the tick and the waterline.
The rivers use the same hues. Each stream carries its headwater's color, and mainstems shade downstream toward the blend of everything they have collected. A small ▼ beside a glass means storage fell over the past week: the reservoir is being drawn down to keep the river below it flowing. Select any reservoir or gage on the flow view and everything off its downstream path dims, so you can follow where that water goes.
Two of the metro area's best-known lakes get a special label. Cherry Creek and Bear Creek are Army Corps of Engineers flood-control reservoirs, not water supply. The pool you sail on is a small permanent one, and most of each dam's capacity is kept empty for a flood. They are on the map because everyone sees them, and because the lake you see is usually not the water you drink.
The winter looked survivable on paper. Then March turned warm early. By the first of June, 91% of the state's SNOTEL snow-measurement sites were bare, and the melt that should have carried rivers through summer came and went in a spike. By late July statewide streamflow was running around 44% of normal, statewide reservoir storage was near 75% of its 30-year median, and the Gunnison basin's glasses, Blue Mesa above all, were visibly draining. Open the timeline and press play to watch it happen. The daily readings on the map carry the story forward from there. The water year ends September 30.
All of it is downloadable as plain CSV, with per-row source and as-of columns. None of it is operational data. For decisions, go to the primary sources.
Drought is easy to ignore from a kitchen tap. The water still comes out, the price barely changes, and the shortage is always somewhere upstream. But every tap in Colorado is at the end of a specific thread: a river, a tunnel, a reservoir in the hills. If you can point at your reservoir on a map and say that one, and it's at 54%, the abstraction gets personal.
Start with your ZIP code and follow the thread from your tap to its basin, its reservoirs, and the tunnels that carry it under the Divide. It is a simplified picture, since utilities blend sources and trade shares constantly, but the thread is real. Share it: water.myjimmycloud.com#80302 opens the story on that ZIP's water.