Why the Roaring Fork Past North Star Ran So Thin This Summer, and What's Flowing Now

How can one river run at 61% of average on the east side of Aspen and 116% of average on the west side on the same day?

That was the split on Oct. 1, 2026, according to Aspen Journalism's streamflow tracker. At Stillwater, upstream of town, the Roaring Fork measured 26.9 cubic feet per second. Below Maroon Creek, the USGS sensor read 144 cfs. Both readings come from the same river in the same drought. The gap between them explains why North Star Nature Preserve, the quiet paddling stretch east of town, became the first place in Pitkin County's history where river access was closed outright.

The Summer North Star Closed

On July 28, 2026, Pitkin County Open Space and Trails closed all river access inside its boundary at North Star Nature Preserve, from just above South Gate to Stillwater Bridge. Flows had been consistently below 20 cfs since July 27. The county's posted notice still allowed visitors on the designated beach but prohibited floating upstream or downstream from it.

The 20 cfs trigger was new this year. Before 2026, North Star had only a voluntary closure threshold, set at 60 cfs. "This is the first year that we've ever instituted a mandatory closure," Jami McMannes, communications and outreach specialist for Pitkin County Open Space and Trails, told The Aspen Times. Ranger Rick Norman said the water had dropped as low as 13.3 cfs.

To put 13.3 cfs in context, the gauge on the Roaring Fork near Aspen peaked at 284 cfs on June 4, 2025.

Two Pressures on One Reach

The first pressure was the winter. Colorado's March 2026 was the warmest in 132 years of records, 3 to 4 degrees Fahrenheit warmer than any March before it, and the snowpack melted at rates more typical of May or June. In the Roaring Fork basin, snow water equivalent peaked at 9.3 inches on March 10. The median peak is 17.1 inches, and it usually arrives on April 7. By April 22, the basin held 18% of its median snowpack. The Aspen Daily News reported that the gauge near Aspen may already have hit its annual high of 79 cfs on March 27. Aspen Journalism's snowpack dashboard shows the basin melted out completely by May 15, two weeks earlier than in 2025.

That drought covered the whole valley. The second pressure falls on the east end in particular.

High on Independence Pass, the Twin Lakes Reservoir and Canal Co. runs a network of reservoirs, tunnels and canals. It collects water from the Roaring Fork headwaters, Lost Man Creek and other tributaries and sends it under the Continental Divide through the Twin Lakes Tunnel. Nearly the entire flow of Lost Man Creek is typically diverted, and water from the Fork and Lost Man joins Lincoln Creek's water at Grizzly Reservoir before heading east. The project can divert up to 46,000 acre-feet a year, which Aspen Journalism puts at nearly 40% of the flows in the Roaring Fork headwaters. Four Front Range water providers own 95% of the shares.

Every one of those diversion points sits upstream of North Star and Stillwater. As of Oct. 1, Aspen Journalism reported that tunnel diversions had reduced the Fork's flow at Stillwater, though the amount diverted has slowly decreased since mid-June. The reporting did not give a 2026 total for the diversion.

The Oct. 1 Readings, Gauge by Gauge

Lined up together, the Oct. 1 readings show how much the Stillwater number depends on that one feature upstream.

1. Roaring Fork at Stillwater, above Aspen and below the Twin Lakes diversion: 26.9 cfs, 61% of average. A year earlier, on Oct. 1, 2025, it ran 36.5 cfs.
2. Crystal River above Avalanche Creek, which has no dams or transbasin diversions: 89.9 cfs, 85% of average.
3. Roaring Fork near Emma, below the Fryingpan, which is dam-controlled: 66% of average.
4. Roaring Fork below Maroon Creek, west of town: 144 cfs, 116% of average.

The Crystal is the cleanest baseline because nothing upstream takes water out of it. In a year the U.S. Drought Monitor still rated as exceptional drought for the Roaring Fork watershed on Oct. 1, an undiverted river ran at 85% of normal. The reach past North Star ran 24 points lower.

Why the River Rises When Twin Lakes Stops

Colorado's priority system sometimes works in the east end's favor. When irrigators in the Grand Valley place what is known as the Cameo call, which happens most summers, upstream users with junior water rights have to stop diverting. Twin Lakes is one of those junior users. When it shuts off, more water stays in the Roaring Fork past Stillwater.

So in a typical summer, the upper Fork depends on two schedules set far from Aspen: when Twin Lakes diverts, and when the Grand Valley calls for its water.

The County Is Buying Water Back

Pitkin County started 2026 by trying to get its own hand on the tap. In January, Commissioner Francie Jacober announced a deal to buy 60 Twin Lakes shares and 34 Fountain Mutual Ditch shares from Castle Concrete Co. and its parent, Riverbend Industries, for $6.5 million. The purchase came to about 71 acre-feet. Only about 45 of those acre-feet are Western Slope water currently diverted to the Front Range. The Fountain shares were a condition of the sale and are not decreed for use west of the Divide. The money comes from the Pitkin County Healthy Rivers fund, which is supported by a 0.1% countywide sales tax.

Scale matters here. Against a system that can divert 46,000 acre-feet a year, 45 acre-feet is a small number. What the county bought is control over timing. It plans to release the water during irrigation season when flows are low, and to hold it when the Cameo call is already adding water to the river. Deputy County Attorney Anne Marie McPhee said the county heard about the shares before they officially reached the market, because "usually the municipalities on the eastern slope are trying to get them as quickly as they can."

"You don't get these opportunities to put physical water in the river anymore, particularly up at the headwaters." — Anne Marie McPhee, Pitkin County Deputy Attorney

By July, The Aspen Times reported that at least some of the county's Twin Lakes water had been released under the Colorado River District's emergency substitute water supply plan. The paper gave no amount and said a full accounting was expected. That water also has to serve a downstream user, because it is not decreed for instream environmental use. The same report described Grizzly Reservoir as drained for dam maintenance this summer, which may have affected how much county water could be released.

Commissioners went back for more. Ordinance No. 025-2026, which authorizes buying another 4.68 Twin Lakes shares for $442,500, was finally adopted after a public hearing on July 22. Closing was anticipated for Sept. 5. Aspen Journalism estimated those shares at about 3.5 acre-feet, which could be as little as 1 cfs for two days. No public confirmation of the closing has appeared yet.

What the River Looks Like From the East End Now

The Oct. 1 Stillwater reading of 26.9 cfs is above the 20 cfs trigger that closed North Star in July. The county's July 28 notice, the latest one we found, says river access "is now closed" and gives no end date, so check with Pitkin County Open Space and Trails before putting a boat in at South Gate.

Anglers have seen the valley loosen up. Colorado Parks and Wildlife began a voluntary noon-to-midnight fishing closure on July 17 for the lower Roaring Fork, from the Highway 133 bridge in Carbondale to the Colorado River confluence. The agency cited flows below 50% of normal and water temperatures above 71 degrees, and noted that upper reaches were cooler. CPW lifted that closure effective Aug. 20 after increased releases from Ruedi Reservoir raised flows and cooled the water. As of Sept. 23, the Roaring Fork Conservancy's drought page listed no fishing closures.

On the east side of town, the reach past North Star is still running at 61% of average, the lowest share on the Roaring Fork Oct. 1 snapshot. Downstream, past Maroon Creek, the same river was running above average that day.

For anyone weighing a property along the upper Roaring Fork, the river itself belongs in the conversation, from how flows behave in a dry year to who controls the water upstream. Hank Carter is glad to walk you through it. Schedule a private consultation.

This article is general information, not legal, tax or financial advice. Consult a qualified professional about your situation.