Westminster Boulevard Drinking Water Project

Water System Overview

The City of Westminster is committed to providing affordable, high-quality water services.

Scroll through the slider to see where your water comes from!

The Front Range is a dry place. Like most communities in Colorado, Westminster's water starts as snowflakes that fall in the Rocky Mountains. About 12 inches of snow melts to one inch of water on average, but that's not always the case. We monitor snow water equivalent, or how much water is contained in snow, at two locations to get a better estimate of how much water is expected during the spring runoff.

The majority of Westminster's water comes from the Clear Creek watershed. Snow across 400 square miles of mountainous terrain surrounding Golden, Idaho Springs, Central City, Georgetown, and Loveland Pass melts in the spring and summer and flows into Clear Creek.

A small portion of Westminster's water comes from the Continental Divide thanks to a long-standing agreement with Denver Water.

Water is serious business in Colorado. Westminster is only allowed to store and use water that it has a right to use.

Westminster partners with neighboring communities and businesses that also rely on Clear Creek to monitor its water quality. Ten monitoring sites take over three million water quality tests each year. If contamination occurs, an automated alert system will alert downstream users.

Canals play a critical role moving water across Colorado, and Westminster is no different. Three different canals are designed to bring water to Standley Lake. In an emergency, canal gates can be adjusted to divert flows from entering Standley Lake.

Standley Lake stores 13 billion gallons of water for Westminster, Thornton, Northglenn, and Farmers Reservoir and Irrigation Company (FRICO). Enough water is stored in Standley Lake to serve Westminster residents and businesses for one and a half years.

The biggest threat to Westminster's water supply is climate variability — drought and wildfire, most specifically. Changes to precipitation and temperatures will affect how much water Westminster may receive in a given year. Staff carefully monitor the City's water supply and plan for the future. Drought is always possible, but Westminster's water supply will remain in good shape if residents continue to conserve water like they have over the last 20 years.

City of Westminster
Water Quick Facts

More than nine billion gallons of water supplied to 33,000 homes and businesses each year.
Two water treatment facilities
- Semper Water Treatment Facility (provides 75% of the City's water).
- Northwest Water Treatment Facility (provides 25% of the City's water).
Over 500 miles of existing potable water pipe.
Water storage facilities throughout the city.

Project Overview

Between 2015-2021, the City evaluated options for a new water treatment facility to provide the community with clean, safe, and affordable drinking water.

The facility will be built on the east side of Westminster Boulevard between 98th and 104th avenues.

The new water treatment facility will eventually replace Semper as it is phased out over the next two decades.

As part of the project, the City would also install a new water supply line, finished waterline, sewer line, and other supporting utilities.

Anticipated Timeline

Project History

The City began planning for a new water treatment facility to replace the Semper Water Treatment Facility.

A reevaluation of the project began after the community raised concerns about affordability.

Under City Council's guidance, different facility options were considered to better balance the community's need for clean, safe, and affordable water.

The reevaluation focused on rightsizing the facility and associated infrastructure, which originally had an inflation-adjusted cost of over $300 million.
Staff assessed and presented alternative sites, facility capacities and treatment capabilities.
The reevaluation resulted in an adjustment of the water treatment facility's capacity. The new conceptual design reduced the facility's treatment capacity by 25% and offered a different mix of water treatment technologies.
The anticipated cost also decreased by $100 million to a more affordable project estimate of $200 million, based on current information.

City Council adopted Resolution 13 directing staff to pursue the design of a substantially different water treatment facility.

Building Responsibly

Updating Westminster buildout demand for drinking water revealed projected demand decreased due to the community's water conservation practices between 2015 and 2022. In 2015, projected buildout demand was 60 million gallons per day (MGD). In 2022, projected buildout demand showed a 25% reduction at 45 MGD.

As a result of this decrease:

For the first phase of the project, the proposed drinking water facility went from two treatment trains to one treatment train with the rightsized treatment capacity decreasing from 30 MGD to 14.7 MGD. A treatment train is a sequence of treatment stages the water flows through.

The water supply line diameter decreased from 42 inches to 36 inches, allowing the waterline to connect to a location that is closer to the site. The subsequent reduction in length resulted in significant cost savings.

The finished waterline diameter decreased from 36 inches to 30 inches.

Why a New Facility?

The 54-year-old Semper Water Treatment Facility is nearing the end of its useful life and will soon be phased out.

The Semper site is inadequate for upgrading the facility to meet current and anticipated regulatory needs. The new facility would provide an affordable solution with the flexibility to:

Replace aging infrastructure and expand if needed.
Respond to future state and federal clean water regulations.
Build additional treatment processes to respond to potential future wildfire or watershed contamination and emerging contaminants.

A Phased Approach

Large water treatment projects are often done in phased construction. This project would be built in phases over the next two decades to manage impacts to Westminster residents and make the full and best use of the portions of Semper that have decades of service life.

Proposed Action - 30% Design

Facility Quick Facts

One treatment train until more are needed due to aging infrastructure at Semper
14.7 million gallons per day (MGD)
Semper would reduce its treatment capacity from 44 MGD to 29.4 MGD
In about 20 years, when it's time to replace the rest of Semper, the new facility would add 29.4 MGD of treatment capacity to the 14.7 MGD for a total of 44.1 MGD
Ozonation would be added to the treatment process on a staggered timeline as funding availability and/or needs occur
At this early stage of the design process the cost estimate for the new drinking water facility has a range of -15% to +30%

Utilities

In conjunction with the new water treatment facility, several supporting utilities would also need to be installed.

Water Supply Line

To access the City's water supply, the project would include a new 36-inch-diameter water supply line to transport untreated water to the new drinking water facility.
The two-mile-long waterline would connect to the new facility at the southern border of the project site.
The new water supply line would connect to the existing Standley Lake raw waterlines.
The proposed tie-in location uses approximately 70% of existing raw water lines and will result in significant cost savings.
While the pipe installation will impact neighborhoods, schools, and traffic, the City is proactively researching methods to reduce and minimize disruptions as much as is feasible.
Approximately 98% of this new waterline will be placed within the City-owned right-of-way, which will result in a limited number of additional easements.

Finished Waterline

A 30-inch-diameter underground finished waterline would deliver drinking water from the facility to our community through a connection along Sheridan Boulevard.
The finished waterline would extend approximately one third of a mile from the eastern boundary of the facility and connect to an existing water main near Sheridan Boulevard.

Sewer Line

Approximately 650 feet of underground sewer line would be installed and connected to an existing sewer main.

Other Supporting Utilities

Gas service
Fiber communications
Electrical service

What is an Environmental Assessment (EA)?

In order to secure federal funding for the drinking water facility, the City is required to conduct an EA of the proposed site. An EA describes how a project will affect people, animals, land, water, and air quality in an area. Should a potentially undesirable impact be identified during the EA, the applicant is required to propose alternative solutions to address the issue. An EA also offers a robust public engagement process, including a public comment period, and requires the City to respond to public comments in the final EA document. The EA will evaluate the facility site, waterline alignments, and cumulative impacts to the City's water service area.

Purpose and Need

Explore the specific purpose and need of the project in more detail below.

The Semper Water Treatment Facility is over 50 years old with a significant number of its assets at or beyond their predicted service life.
Semper's aging condition makes it costly to maintain and vulnerable to water-quality challenges due to drought and wildfire.
Increasingly stringent state and federal clean water requirements will make Semper more expensive to operate and maintain.

Source water refers to sources of water such as rivers, lakes, and reservoirs, that provide water to public drinking water supplies. The City's source water is susceptible to water quality challenges due to the increased frequency and severity of drought, floods and wildfires in the Clear Creek watershed.
Wildfires in our watershed can cause poor raw water conditions that can last for months or even years. We have had high-quality raw water because there has not been a wildfire in the Clear Creek watershed for over 50 years. Northwest Water Treatment Facility has reliably treated raw water with a wide range of water quality. When raw water conditions are challenging, the City will not be able to rely on Semper to produce drinking water as consistently as Northwest.

Semper likely cannot treat the anticipated quality of source water under potential future drinking water regulatory standards.
Federal drinking water regulations change over time. When Semper was built 50+ years ago, regulations were very different from what they are today. Semper would not be approved by state and federal regulators for construction today because it does not meet current regulatory standards. Regulators continue to evaluate and rerate existing treatment facilities over time for treatment capacity. In the past year, Semper and other similar facilities have seen their rating adjusted downward by state regulators.

Semper lacks sufficient space to reliably produce and deliver drinking water when portions of the facility come due for replacement in upcoming years.

Alternatives

The EA considers two alternatives:

No Action Alternative: No construction and the existing site and infrastructure remain unchanged.
Proposed Action:
- New 14.7 million gallons per day (MGD) drinking water facility
- Tie into the existing water supply lines with a new pipe to deliver raw water to the new facility
- New finished waterline to connect the facility to the existing distribution system
Other action alternatives were considered, including alternative waterline alignments, alternative facility and associated infrastructure sizing, treatment capacities, and treatment capabilities.

Impacts on the Human Environment

The table below describes the relative impact of the project to various human environment factors.

Factor	Negligible or No Effect	Minor Effect	Moderate Effect	Potential Positive/Negative Project Effects	Avoidance/Minimization/Mitigation Measures
Cultural, Historical, & Paleontological Resources		X		No anticipated impact to known cultural, historical, or paleontological resources Unknown cultural resources could be uncovered during construction	Complete pedestrian surveys of portions of project area not yet surveyed Implement Inadvertent Discovery Plan that includes procedures in the event human remains, cultural resources, or paleontological resources are uncovered during construction Consult with State Historic Preservation Office (SHPO)
Environmental Justice	X			No disproportionately high and adverse impacts for minority and low-income populations when compared to the general population
Land Use		X		Change in land use at drinking water facility site Project is consistent with City's Comprehensive Plan
Public Health		X		Exposure to occupational human health and safety risks by construction workers and operations staff Allows greater resiliency to address potential future source water and drinking water quality challenges	Implement best management practices and standard operating procedures to minimize impacts to worker and staff health and safety
Recreation		X		Short-term and temporary trail and open space closures during construction	Provide advanced notification to the public of closures and provide signage directing users to alternate routes and/or facilities
Socioeconomics	X			Short-term and temporary benefit to economy from influx of construction workers spending locally Long-term benefit from creation of new jobs at the drinking water facility
Transportation		X		Short-term and temporary increase in traffic associated with construction Road closures/detours during construction Minor long-term increase in traffic associated with operations	Prepare Traffic Management Plan Provide advanced notification to the public and emergency service providers of closures/detours and provide signage directing users to alternate routes
Utility Services		X		Potential for short-term and temporary utility interruptions during construction	Schedule during non-peak use periods Limit utility conflicts through design Provide advanced notification to customers about planned service disruptions during construction
Visual			X	Short-term and temporary visual impacts associated with construction activities New visually dominant feature New source of light/glare	Incorporate Uniform Development Code standards for exterior treatments, lighting and illumination, and vegetation screening into drinking water facility design

Negligible/None: There would be no measurable or perceptible impact.

Minor: The impact would be measurable or perceptible, but it is slight and would only affect a limited area of a resource or group of resources.

Moderate: The impact would be measurable and perceptible.

Major/Significant: The impact would be substantial, noticeable, and permanent.

Impacts on the Physical Environment

The table below describes the relative impact of the project to various physical environment factors.

Factor	Minor Effect	Moderate Effect	Potential Positive/Negative Project Effects	Avoidance/Minimization/Mitigation Measures
Air Quality	X		Short-term and temporary increase in air pollution during construction Minor increase in air pollution from periodic operation of drinking water facility emergency generators	Complete Air Pollutant Emissions Notice Implement construction best management practices, such as: minimize idling of construction equipment, fugitive dust control, etc.
Floodplains	X		Some water or sewer line installations would occur within a floodplain	Obtain Floodplain Development Permit
Geology & Soils	X		Erosion and sedimentation during construction	Implement control measures, such as: silt fences, erosion logs, vehicle tracking pads, good housekeeping practices, etc.
Hazardous Materials	X		Accidental spills associated with the use of hazardous materials during construction and operation (e.g., fuels, oil, chemicals, etc.)	Prepare Spill Pollution Prevention Plan, Health and Safety Plan, and Emergency Response Plan Incorporate secondary containment features into drinking water facility design
Noise & Vibration		X	Short-term and temporary increase in ambient noise levels due to construction activities Increase in ambient noise from operation of drinking water facility	Implement construction best management practices, such as: follow noise ordinance, install noise control techniques on construction equipment, etc. Complete additional operational noise assessment further in design process Incorporate noise mitigating features into drinking water facility design where possible
Water Quality	X		Erosion and sedimentation during construction Accidental spills	Obtain Construction Stormwater Discharge Permit and Dewatering General Permit Prepare Stormwater Management Plan and implement control measures specified in it Implement construction best management practices to protect nearby waters Prepare Spill Pollution Prevention Plan

Impacts on the Biological Environment

The table below describes the relative impact of the project to various biologic environment factors.

Factor	Negligible or No Effect	Minor Effect	Moderate Effect	Potential Positive/Negative Project Effects	Avoidance/Minimization/Mitigation Measures
Migratory Birds			X	Short-term and temporary disturbance during construction Habitat for migratory birds and raptors present Active raptor nest present in project vicinity	Implement Tree Removal Plan that includes measures to reduce or avoid impacts to migratory birds and raptors Conduct pre-construction nest clearance surveys Consult with Colorado Parks and Wildlife (CPW) and U.S. Fish and Wildlife (USFW)
Terrestrial & Aquatic Wildlife		X		Temporary disturbance during construction Work within Aquatic Sportfish Management Waters High Priority Habitat buffer	Consult with CPW and USFW on activity buffers for work within Aquatic Sportfish Management Waters and appropriate construction best management practices to be implemented for protection of water and wildlife
Threatened & Endangered Species			X	Habitat for federally-listed species not present Habitat for state-listed burrowing owl, bald eagle, and black-tailed prairie dog potentially impacted	Conduct pre-construction burrowing owl surveys Implement prairie dog relocation/removal effort
Vegetation & Noxious Weeds			X	Temporary impacts to upland vegetation during construction Permanent removal of trees Spread of noxious weeds	Prepare Tree Mitigation Plan and Noxious Weed Management Plan Revegetate/reclaim disturbed areas with approved native seed mix
Wetlands/Waters of the U.S. (assumes horizontal directional drilling)	X			No impacts to wetlands
Wetlands/Waters of the U.S. (assumes open cut trenching)			X	Temporary impacts to wetlands	Obtain Clean Water Act Section 404 Permit from USACE

Funding and Rates

Funding is anticipated to be a mix of sources: grants, cash on hand, municipal revenue bonds, Drinking Water Revolving Fund financing from the state, and Water Infrastructure Finance and Innovation Act financing from the federal government.

The near- and long-term fiscal plan for the water utility currently includes annual rate adjustments over the next decade to support:

Operations and maintenance of the system

Current and future debt service obligations

The defined 2024-2028 Capital Improvement Plan, including a new water treatment facility and other important repair and replacement infrastructure projects

This information is based on current data and is subject to change as more project details are determined.

Your Voice Matters

The comment period closed Thursday, October 12. Comments will be included and addressed as applicable in the final EA and future design phases. Please check back for future opportunities to provide feedback.

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