Sustainable Water Resource Stewardship

Denver Water’s strong eco-centric focus permeates all aspects of its operations

Sustainable Water Resource Stewardship

Denver Water process area engineer Jen Gelmini leads a small project tour of the Northwater treatment plant site. (Photography by Carl Scofield )

Sustainability is as central to Denver Water’s operations as the Rocky Mountains’ snowmelt is to its water supply.

An ecocentric mindset informs almost every aspect of the utility’s operations, as evidenced by its net zero energy usage, water reuse programs, LEED-certified buildings (Leadership in Energy and Environmental Design), watershed restoration projects and an emphasis on reducing greenhouse gas emissions.

The Association of Metropolitan Water Agencies recognized the utility’s efforts with a Sustainable Water Utility Management Award in 2021, one of four awarded nationwide; the utility also won the award in 2018.

Moreover, in 2020, the Colorado Department of Public Health and Environment awarded the utility a gold certification in its Environmental Leadership Program. And in 2019, The Climate Registry, a national nonprofit organization, elevated the utility to gold status for its 10-year efforts to quantify its carbon emissions.

A driving force behind the utility’s commitment to sustainability is its reliance on snowmelt from the Rocky Mountains to supply water for its roughly 1.5 million customers in Denver and surrounding suburbs. In short, what’s good for the environment is good for the water supply and for metropolitan Denver residents, says Brian Good, chief administrative officer.

“In our 100-year history, Denver Water always has been tied closely to the environment,” he says. “Our natural resources and the product we deliver are inextricably linked. So caring for our resources allows us to provide better service.

“But it goes beyond just water conservation. Our goal is to sustain the community forever, so we need to do our part to be sure we don’t impact the environment any more than we have to.”

The commitment to sustainability is reflected in its 2021-2025 Sustainability Guide, which builds on an earlier guide developed in 2018. Goals set in the current guide include a 50% reduction in greenhouse gas emissions from a 2015 baseline; increasing the utility’s capacity to generate renewable electricity by 1 megawatt; and reducing landfill and electronic waste by 25% from a 2020 baseline, says Kate Taft, hired in 2016 as a sustainability manager.

“Sustainability is an organizational priority and this guide reflects that,” she says.

Net-zero energy status

In 2020, the utility reached a landmark goal: net-zero energy usage, which essentially means Denver Water produces more electricity/energy — via “green” sources that don’t generate carbon emissions — than it uses. Excess electricity is sold back to a local electric utility, Taft says.

But Denver Water officials note that net-zero energy usage isn’t achievable every year because large maintenance projects occasionally take hydroelectric facilities offline for periods of time, which decreases electricity production. This occurred in 2021.

“Energy efficiency is a big deal for us,” Taft notes. “We’ve brought on board an energy management specialist that works with our operations to implement efficiency improvements and upgrades. This covers everything from small projects to major renovations and construction projects.”

The utility gets a strong energy assist from Mother Nature, courtesy of the mountainous terrain and fast-running rivers in the utility’s primary, high-elevation watersheds, located south and west of Denver. The utility has built small hydroelectric plants in seven strategically located dams; these turbines collectively produce about 65 million emission-free kilowatt hours of electricity per year, which saves its ratepayers about $4 million annually, Good says.

“We’re able to generate electricity by using elevation and gravity,” he explains. “Before water reaches our treatment plants, it flows through hydroelectric turbines that generate electricity.”

The hydroelectric plants are responsible for most of the utility’s ability to achieve net-zero energy usage, Taft says.

In addition, the utility is building a new water treatment plant that will be energy self-sufficient. The Northwater Treatment Plant is under construction at the Ralston Reservoir, about 15 miles northwest of downtown Denver. It will run on hydropower and will actually generate more electricity than it uses annually, Good says.

When the plant goes online in 2024, it will be capable of treating up to 75 million gallons of water per day. The $520 million price tag includes upgrades to the aging Moffat Water Treatment Plant in Lakewood, which was built in 1937 and will eventually become a water distribution facility.

Like other new facilities at Denver Water, the Northwater plant’s operations building will be LEED-certified, which means it meets a stringent set of energy conservation criteria developed by the U.S. Green Energy Council. The plant recently earned an Envision Gold Award from the Institute for Sustainable Infrastructure.

Eco-friendly facilities

A new Denver Water administration building also strongly reflects the utility’s emphasis on sustainability. The six-story-tall, 186,000-square-foot facility is the crown jewel of a $195 million modernization of the utility’s 35-acre operations complex, completed in 2021.

The project included demolition of 15 obsolete buildings, renovation of two existing buildings and the construction of six new buildings. Seven of the buildings achieved either Silver or Gold LEED certifications and the administration building earned a Platinum ranking, the highest level of certification.

During demolition of the aging buildings — one was 180 years old — 81% of construction debris was diverted from landfills via recycling. That means nearly 30 tons out of almost 37 tons of total debris were recycled, according to utility statistics.

The administrative building achieved net-zero energy status, thanks to 1,126 rooftop solar panels, plus another 1,260 atop a parking garage. The panels are expected to produce about 1,350 megawatt-hours of clean electric power per year, which offsets greenhouse-gas emissions roughly equivalent to burning 1 million pounds of coal, officials say.

In addition, the building features more than 70 miles of heating and cooling tubes in its concrete-floor slabs, part of a unique radiant heating system that works similar to geothermal heat-pump systems. Hot water is piped through the system in winter and cool water in the summer; it makes the building 30% to 50% more energy efficient than conventionally built buildings because it largely eliminates the need for burning natural gas or using electricity for heating and cooling.

“Using energy efficiently, as we’re doing to heat and cool our headquarters, is another example of our commitment to environmental stewardship,” Taft says.

Other eco-friendly elements include high-efficiency insulation; efficient LED lights (which are used throughout the campus); triple-pane glass windows that help regulate penetration of heat and cold; window blinds that respond to changing sunlight conditions; larger windows and skylights for maximum “daylighting;” controlled electrical outlets in non-operations buildings that automatically turn off computer monitors and other equipment in unoccupied spaces; and a comprehensive recycling and composting program.

The building also is designed to capture, treat and reuse rainwater for campus irrigation. It also includes an on-site wastewater treatment facility that recycles wastewater from the building for toilet flushing and irrigation.

“This is the first system of its kind in Colorado,” Good points out. “The system has a capacity of 7,000 gallons per day and will treat water using aerobic and anaerobic processes, wetlands treatment, filtration, ultraviolet light and chlorination.

“We hope that this system demonstrates the future of wise urban water use in Colorado and paves the way for others to install similar systems.”

Forest-fire mitigation

Other sustainability efforts occur far away from Denver in the utility’s roughly 4,000-square-mile water collection system, which includes 17 reservoirs (plus storage rights in another one owned by the U.S. Army Corps of Engineers) and four water treatment plants. The collection system is divided into two systems, north and south, with the south supplying about 80% of the utility’s water.

A good example of outlying sustainability initiatives is the Forest to Faucets watershed management program, a joint effort with the Rocky Mountain Region of the U.S. Forest Service and the Colorado State Forest Service. The initiative was spurred by two devastating wildfires in 1996 and 2002 that forced the utility to spend nearly $28 million for water treatment and sediment/debris removal.

The goal is to maintain healthy forests that can mitigate the potential for forest fires, Good says.

“Disastrous wildfires can wreak havoc on the places where our water comes from. The impact of wildfires and the cost of recovering from them is very significant.”

For example, after forest fires, sediment runs into rivers and creeks because there’s no vegetation left to hold the soil in place; this also reduces natural filtration of water provided by vegetation. The sediment can clog creeks and reservoirs, Good notes.

Furthermore, the sediment can change the water chemistry — and as a result, its quality. The more sediment present in the water, the more likely that troublesome minerals such as manganese and iron will build up and make treatment more difficult.

As such, the utility has contributed roughly $32 million to the Forest to Faucets program. That includes funding to plant more than a million trees since 2010 and tree- and brush-thinning in areas identified as priorities by federal and state forest service officials.

“An ounce of prevention is worth a pound of cure,” Good says.

Carbon-footprint reductions

Denver Water also strives to lower its carbon emissions. Since 2008, it has partnered with The Climate Registry, a nonprofit group that sets standards to calculate and verify greenhouse gas emissions and then publicly report them to a central clearinghouse.

In 2019, the TCR gave Denver Water “gold” status, its highest ranking, for its efforts to reduce the utility’s carbon footprint. To provide accurate intel to the registry, a sustainability team tracks everything from electricity usage and vehicle emissions down to energy used for refrigeration and welding.

From 2008 to 2019 (the latest year for which data is available), the utility reduced its carbon emissions by nearly 36%, from just under the equivalent of 70,000 metric tons of carbon dioxide to 45,000 metric tons.

“We’re also looking at our vehicle fleet in an effort to reduce fuel usage,” Taft notes. The utility ordered 15 hybrid-electric vehicles last year, but only received six because of supply-chain issues. The utility also has ordered 10 fully electric-powered pickup trucks.

“As the automotive industry starts to produce larger vehicles and heavy equipment that are fueled renewably, we’ll bring those into our fleet as well,” she says. “We’re excited to see what auto manufacturers can do in the future.”

More in store

Denver Water’s commitment to sustainability includes many more programs and goals, such as plans to reduce fleet-vehicle idling, using software that monitors idling for all vehicles; develop more drought-tolerant landscaping on utility properties; and decrease paper usage 50% by 2025, using 2019 as a baseline.  

The utility also runs the largest water-recycling system in Colorado. It treats and returns up to 21 million gallons of water per day to industrial and commercial operations during peak operations; some of it also is used for irrigation. In 2021, the utility recycled slightly more than 2.5 billion gallons of water, Good says.

The recycled water, which travels to customers through a separate system of pipes, would otherwise be treated and discharged into the South Platte River.

This laser-like eco-focus on sustainable operating practices isn’t unusual for the 104-year-old utility, which started focusing on water conservation back in the 1930s by putting signs on streetcars urging residents to conserve water. But maintaining momentum will not be easy; it will require constantly rethinking and redefining what sustainability means to the utility, given climate change, regulatory uncertainties and economic and social changes, to name a few factors, officials note.

“Sustainability for the next 100 years will require continued reinvention, resilience and adaptability in everything we do,” says Jim Lochhead, the utility’s chief executive officer. “But it’s at the heart of everything Denver Water does.” 



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