Ziegler Reservoir: Sustainable water management in Snowmass | AspenTimes.com

Ziegler Reservoir: Sustainable water management in Snowmass

Steve Alldredge
Special to the Snowmass Sun
Ziegler Reservoir holds roughly 82 million gallons of water and is about 252 acre-feet in size.
Aubree Dallas/Snowmass Sun |

Since the last ice age receded, water in Snowmass Creek has flowed from the Maroon Bells-Snowmass Wilderness, carving out what’s known as the Snowmass Creek Valley. The water irrigates ranches and supports wells for a few subdivisions and scattered homes before joining the Roaring Fork River in Old Snowmass.

Over time, additional demands for water to support the development of Snowmass Village and snowmaking at the Snowmass ski area added to the pressures on Snowmass Creek, giving rise to concerns over the preservation of sustainable flows in the creek. But the inevitable conflict, which first existed between users in the Snowmass Creek Valley and those in the Brush Creek drainage over the water in Snowmass Creek, is now developing into a novel and promising partnership to manage and protect water that people in both valleys depend on.

The centerpiece in this partnership is Ziegler Reservoir.

The creation of this off-stream reservoir provides the flexibility and water security to support a 21st-century approach to sustainable water management where water is shared between agriculture and a municipality and across two basins.

When the resort of Snowmass Village was created in 1967, senior water rights from Snowmass Creek pertaining to the underlying ranch lands were converted to serve the newly planned community, the tourist condominiums and hotels, and, eventually, snowmaking at the ski area. The Snowmass Water and Sanitation District was created to provide clean water and treat wastewater for a growing base of Snowmass customers at the new resort.

More than 96 percent of the district’s water flows from the Snowmass Creek Basin. East Snowmass Creek provides most of that water, with the rest coming from Snowmass Creek. Less than 5 percent of the sanitation district’s water comes from Brush Creek. All of the water from East Snowmass Creek is gravity-fed down to the water-treatment plant at the bottom of the Snowmass ski area.

Over the years, the shared use of Snowmass Creek water became a contentious issue between residents in Old Snowmass and the Snowmass Water and Sanitation District — particularly in the winter. The town of Snowmass Village needs the most water in winter around the holiday season, when the low temperatures of December and January cause the lowest flows in the creek. When the need for water for snowmaking was added in the ’90s, the pressure on Snowmass Creek increased.

Worried about the health of Snowmass Creek, the Snowmass-Capitol Creek Caucus challenged the Snowmass Water and Sanitation District and Aspen Skiing Co. over minimum stream flows in Snowmass Creek. In 1996, the Colorado Water Conservation Board established a stair-step minimum stream-flow baseline for Snowmass Creek in an attempt to balance human and environmental demands for the water. But tensions remained among the Snowmass Water and Sanitation District, the Snowmass-Capitol Creek Caucus and Skico because the minimum in-stream flow rights set by the state are not binding on more senior water-right holders like the sanitation district.

Chelsea Congdon is a member of the Snowmass-Capitol Creek Caucus and a leader in its efforts to protect Snowmass Creek.

“Snowmass Creek has shaped and defined the Snowmass Creek Valley, and it is literally the lifeblood of all the ecosystems of this valley,” Congdon said. “That creek is shared by people in two watersheds, and the caucus spent a lot of time and a lot of money trying to find a way to compel or convince (the sanitation district) to join in the effort to protect that creek.”

Sharon Clarke is the watershed action director for Roaring Fork Conservancy, a local environmental organization dedicated to water.

“For a lot of years, it was very contentious between the (sanitation district) and the Snowmass Creek Caucus,” Clarke said. “Now they are working together to figure out how to best get water for the district and help the creek at the same time.”

A significant factor in that transition was the staff and board changes at Snowmass Water and Sanitation District in the early 2000s, when Kit Hamby was hired as district manager. Doug Throm was a member of the Snowmass Water and Sanitation District board from 2004 until 2014.

Since he was hired by the Snowmass Water and Sanitation District, Hamby has initiated a series of operational changes to increase water-conservation programs and manage water more efficiently. After instituting a study on the district’s water assets and future needs, Hamby led an effort to expand raw-water storage to mitigate the catastrophic effects of a natural disaster or drought. This effort led to the district purchasing a small pond in 2008 located on top of a hill overlooking Snowmass Village for $3.5 million from the Peter Ziegler family.

In October 2008, construction of Ziegler Reservoir began and then quickly came to a stop: During excavation, bulldozer operator Jesse Steel unearthed bones from a female mammoth. Two extensive digs by the Denver Museum of Natural History uncovered bones from a wide variety of animals that lived more than 45,000 years ago. They also discovered one of North America’s premier locations to study climate science.

After the digs, Ziegler Reservoir was completed and put into service by the Snowmass Water and Sanitation District. The reservoir holds roughly 82 million gallons of water and is about 252 acre-feet in size.

The original plan for the reservoir was to hold water for an emergency. But Hamby led an effort to develop a plan to use Ziegler Reservoir to do more — to serve as the linchpin in a state-of-the-art municipal water system, with conservation at its core.

“Using Ziegler is a balancing act,” Hamby said. “We fill the reservoir when water flows in the creek are high and then use that water when flows are low. And it’s an extraordinary water-management tool. We can take out 104 million gallons for snowmaking and then take another 100 million gallons out over the next three months for municipal use and still not drop the reservoir below 50 percent.”

Frank White is the snowmaking manager for Skico. After Ziegler Reservoir came online, Skico concluded a multiyear agreement to use the water from Ziegler Reservoir for snowmaking. In an average year, Skico uses about 80 million gallons of water for snowmaking at the Snowmass ski area over a 60-day period.

White recalls how snow was made at the Snowmass ski area by pumping water out of Snowmass Creek and up the hill to snow guns that roared to life and spit out snow when temperatures were low enough. Those same low temperatures often occurred when Snowmass Creek was at its lowest flow, stressing the health of the Snowmass Creek ecosystem. With the construction of Ziegler Reservoir, the company takes water for snowmaking out of the reservoir without impacting the creek and also saves the expensive cost of using energy to pump the water uphill.

Auden Schendler is Skico’s vice president of sustainability.

“If you are going to make snow, it’s more efficient to make it all at once,” Schendler said. “In the past, we couldn’t do that because we were limited on how much water we could take out of the stream when temperatures were the lowest. Now, we can fire on all cylinders and pump out as much snow as efficiently as possible during a cold snap. Using Ziegler saves energy and therefore money. And using Ziegler buffers Snowmass Creek because not as much water is withdrawn when the flow of the creek is at its lowest.”

Using Ziegler Reservoir for snowmaking and municipal demand during the winter so that Snowmass Creek is protected from diversions is one benefit most everyone agrees on.

Dave Nixa is on the board of the Pitkin County nonprofit Healthy Rivers and Streams.

“I think the most significant aspect of Ziegler Reservoir is that it is a tremendous resource for storage in case of landslides, fires and other catastrophes,” Nixa said. “But we need to maintain the riparian life of (that) creek and the animals that use it, and the biggest animal that uses that creek is man, for domestic water and irrigation. Having that kind of resource in our valley is pretty important in protecting the long-term health of Snowmass Creek.”

In the 1990s and 2000s, the focus of the Snowmass-Capitol Creek Caucus was on maintaining a minimum stream flow in Snowmass Creek in order to maintain healthy flows to protect river ecology — and most people measure river health by the health of fish populations. In this case, the fish is trout.

Trout spawn at different times of the year. They lay their eggs in nests in the gravel of the stream. The eggs laid in the fall are susceptible to low winter stream flows. If the water gets too low, the nests become exposed and freeze. If the water gets too low and anchor ice forms on the bottom of the stream, the ice starts moving, and it destroys the nests.

“Before Ziegler was built, the creek’s flow was the lowest at the same time of the year that beds in Snowmass Village were filled and snowmaking was needed,” Congdon said. “Now, the district is using Ziegler as a bucket, and they use that off-stream storage of Ziegler as part of a water-management system, filling the reservoir back up when the creek has excess water and using the reservoir to buffer the creek.”

In addition to using Ziegler as a water-management tool, the sanitation district has earned high praise from the caucus and others because of additional investments in sustainability they have made the past few years.

“Other than building Ziegler, we have focused in on water loss,” Hamby said. “We probably have the most aggressive leak-detection system in the state of Colorado. We perform leak detection on about 60 to 80 percent of our 45 miles of water line each spring, and then we retest about 40 to 45 percent of those lines again each fall. Each year, we’re retesting 100 percent of our lines.”

“The district has a keen awareness in how to manage their resources in the most effective way,” Nixa said. “One good example is their leak-detection program. It was probably in the upper percentile of poor and is now in the lower percentiles of outstanding. I would venture that the (sanitation district) is in the top 1 percent of all water districts in the state. It’s a formal program and inherent in how they run their business now.”

In fact, the conservation and leak-detection programs of the sanitation district have reduced overall water usage in the district from 642 million gallons in 1998 to about 480 million gallons a year now.

“The district has made huge investments in storage, conservation and leak detection, and their current low water-loss rate makes them a state-of-the-art water district,” Congdon said. “They are protecting their rate payers and delivering water without wasting money. And they are operating with an awareness that we all depend upon this one little creek. We should manage it efficiently.”

As a testament to the commitment to conservation, in December, the Snowmass Water and Sanitation District Board passed resolution No. 9 to operate its water system to adhere to the state minimum in-stream flow standard for Snowmass Creek to the maximum extent possible.

The district’s commitment to use Ziegler Reservoir to manage water more efficiently and protect the creek has helped motivate the Snowmass Creek Caucus to lead a water-conservation and education effort in the Snowmass Creek Valley.

While the Snowmass Water and Sanitation District is the largest user of Snowmass Creek water in the winter, the irrigators of the ranches and farms in the Snowmass Creek Valley use the most water in summer. Even though they use their water at the time of the creek’s highest flows, their cumulative demand, coupled with the pressures of climate change, threatens the health of Snowmass Creek in the summer.

Under the most accepted assumptions of climate change, the historic diversions in the Snowmass Creek Valley are predicted to begin to drive late summer flows below the summer in-stream flow level of 15 cubic feet per second. The Snowmass-Capitol Creek Caucus has initiated an outreach effort to work with local irrigators to find ways to increase water efficiency. Some irrigators in the valley, including the McBrides and Wildcat Ranch, have installed sprinkler systems that use less water and use it more efficiently than traditional flood irrigation systems.

“One of the biggest things the caucus is doing now is education,” Congdon said. “We’re developing information materials and meeting with irrigators to help them understand the issues, and we’re getting their commitment to conserving water in times of low flows, which is a huge commitment for them to make, and it’s voluntary.”

In order to conserve and manage water the most efficiently, the water has to be gauged and measured. Both the Snowmass Water and Sanitation District and the Snowmass-Capitol Creek Caucus are currently leading efforts to construct small barriers to more effectively measure stream flows on Snowmass Creek and its tributaries.

Today, the disputes between the Snowmass Water and Sanitation District and the Snowmass-Capitol Creek Caucus seem like a thing of the past. The construction of Ziegler Reservoir was something water users in both the Brush Creek and Snowmass Creek drainages could agree on. And it has proved to be the keystone in an unlikely partnership between municipal and agricultural water users in two basins to protect a shared stream.

It is not unusual for rivers or streams in Colorado to be diverted from one basin to another, but it is rare to find such a promising collaboration across such a divide. If the predictions for climate change in this region are accurate, and demands for water continue to grow, as they surely will, then the story of conservation and cooperation around Snowmass Creek could be a model for other water users in the West.


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