Frequently Asked Questions about Moffat Collection System Project

Denver Water is proposing to enlarge Gross Reservoir to help resolve three major water supply challenges: the risk of a near-term water supply shortfall; the risk of running out of water in the north end of our system during a single dry year; and a serious imbalance in our water collection system.

Since 1997, Denver Water has pursued a multi-pronged approach to increase supply and decrease demand through: 1) implementing an aggressive conservation plan, 2) constructing a recycled water treatment plant and distribution system, and 3) developing additional water supply. We are vigorously implementing the first two strategies and will continue to do so, but we also need to increase water supply.

In 2003, Denver Water contacted the U.S. Army Corps of Engineers (Corps) about obtaining a permit to build a project to help address our water supply challenges. The Corps determined that an Environmental Impact Statement (EIS) was needed to analyze potential impacts from the project and to help with the Corps’ decision-making. The Corps examined more than 300 alternatives to meet Denver’s purpose and need, and identified five “practicable alternatives” to analyze in detail in the EIS.

Of the five alternatives, Denver Water believes enlarging Gross Reservoir by 72,000 acre-feet would deliver the most benefits at the least cost and with similar environmental impacts compared with other practicable alternatives.

There are three main reasons Denver Water believes the Moffat Collection System Project is necessary:

• Supply: Denver has identified a shortfall in supply that begins in approximately 2016 and grows to 34,000 acre-feet per year by 2030. Approximately 16,000 acre-feet per year of the shortfall is expected to be addressed through additional conservation, leaving Denver Water with a need to develop 18,000 acre-feet per year of new supply.
• Reliability: During the 2002 drought, Denver Water came perilously close to running out of water in the Moffat Collection System. Without water in this system, we would lose the operation of one of our three treatment plants and have difficulty meeting the needs of our treated water customers and raw water contractors such as Arvada, Westminster, Consolidated Mutual and others.
• Vulnerability: Denver Water’s collection system is vulnerable to manmade and natural disasters, such as forest fires. Approximately 80 percent of our water supply relies on the unimpeded operation of Strontia Springs Reservoir. Emergencies above this reservoir threaten the operation of the entire system, as the Hayman and Buffalo Creek fires highlighted in recent years.

If approved, the Moffat Collection System Project would produce 18,000 acre-feet of new supply — enough water for roughly 45,000 households annually — by expanding an existing reservoir, rather than building a new one.

Denver Water has an internationally recognized conservation program. In 2007, there was $11.3 million spent on conservation in Colorado — $8 million of that was by Denver Water. The utility continues its aggressive conservation campaign and designation of significant funds toward that end. Denver Water is in the midst of a proactive plan to get 16,000 acre-feet of savings by 2016.

Some key Denver Water conservation facts:

• All Denver Water customers are metered.
• Denver Water rates are based on an increasing block rate structure, meaning the more you use, the more you pay.
• Denver Water customers must follow mandatory summer watering rules, enforced by water monitors, that include:
  • No watering between 10 a.m. and 6 p.m.
  • No watering during rain or strong winds
  • No watering sidewalks and streets
• Denver Water’s conservation program includes residential water fixture rebates; requiring new homes and buildings to amend their soil with compost to help retain water; incentives to commercial and industrial customers, and much more.

Visit our Conservation pages for more information.

The Moffat Collection System Project would have several key benefits, as it would:

• be implemented alongside Denver Water’s aggressive conservation effort, construction of a recycled water system and improved water efficiencies throughout the system;
• produce new water supply by expanding an existing reservoir rather than building a new one;
• reduce the chances of Denver Water running out of water during a single dry year;
• increase the overall balance, flexibility and reliability of Denver Water’s collection system, and enhance operations of the treatment and distribution systems; and
• strengthen Denver Water’s ability to provide high-quality water to our customers.

The U.S. Army Corps of Engineers (Corps) is responsible for all aspects of the Environmental Impact Statement (EIS) process. The Corps is preparing an EIS to evaluate the environmental consequences of Denver Water’s proposed alternatives to increase water supply. An EIS is a document required by the National Environmental Policy Act (NEPA) for federal government agency actions “significantly affecting the quality of the human environment.”

Although the Corps is not proposing, designing, funding or constructing the Moffat Collection System Project, it will require a Section 404 Permit, which is a federal permit required under the Clean Water Act. The Corps is neither an opponent nor a proponent of proposed projects, but it examines the environmental consequences on behalf of the public.

The NEPA process is designed to involve the public and gather the best available information regarding the project so decision-makers can be fully informed when they make their choices. An EIS describes the positive and negative environmental effects of proposed agency action, cites alternative actions and mitigation for negative impacts.

The proposed Moffat Collection System Project would increase Gross Reservoir from its current storage capacity of 41,811 acre-feet to approximately 114,000 acre-feet — an increase of 72,000 acre-feet (one acre-foot is equal to 325,851 gallons of water and will supply about 2.5 single-family households for a year).

The current dam height would be increased by 125 feet (from 340 feet to 465 feet). Gross Reservoir originally was designed to be this size, but because of budget constraints in the 1950s, a smaller dam was constructed. Connecting facilities, such as the Moffat Tunnel and South Boulder Canal, would not need to be modified.

We have determined we will need an additional 18,000 acre-feet of water supply every year. However, in order to ensure we have that amount every year (called “firm yield”), we need 72,000 acre-feet of water stored in Gross Reservoir. It’s like a savings account for drought years. An additional 72,000 acre-feet of water in storage at an enlarged Gross Reservoir would supply Denver Water customers with 18,000 acre-feet of new supply each year over a four-year drought period. That’s called the “storage to yield” ratio, which is 4:1 at Gross Reservoir.

Gross Reservoir has been and will continue to be a recreational amenity in Boulder County. If the project is approved, some of the existing recreation facilities that need to be moved for the expanded reservoir will be relocated to higher elevations. The surface area of the reservoir would expand from about 400 acres to 800 acres, but Denver Water does not plan to expand existing recreation opportunities. See a detailed plan for the proposed relocated facilities.

Of the five alternatives analyzed by the U.S. Army Corps of Engineers, enlarging Gross Reservoir by 72,000 acre-feet is the least expensive. The Environmental Impact Statement estimates that construction will cost about $140 million and the annual operating costs will be about $300,000. Denver Water will refine this estimated cost during the design phase, which likely will be in 2010 to 2012. As a public agency, Denver Water is funded entirely through rates, new tap fees and the sale of hydropower. No tax dollars are directed to Denver Water or its projects.

No. The existing homes that surround Gross Reservoir are located above the proposed new high water line. No homes would need to be moved.

Yes. The U.S. Army Corps of Engineers is analyzing five alternatives in the Environmental Impact Statement, which encompass a broad range of potential water supplies and storage sites. The alternatives include various combinations and sizes of a Gross Reservoir enlargement, as well as a new reservoir site, gravel pit storage and deep aquifer storage. All the alternatives use Denver Water’s supplies from the Fraser River, Williams Fork River, South Platte River and South Boulder Creek to varying degrees. Three alternatives use agricultural water rights or reusable water to reduce the portion of supply derived from additional transmountain diversions.

Of these options, Denver Water believes enlarging Gross Reservoir by 72,000 acre-feet would deliver the most benefits at the least cost and with similar environmental impact compared with the other practicable alternatives.

Denver Water is working with interest groups and other local agencies to develop a mitigation plan to offset environmental effects of the proposed Moffat Collection System Project. In addition to fully mitigating project impacts as part of the Draft Environmental Impact Statement process, Denver Water has offered environmental enhancements, including:

• up to 2,000 acre-feet of additional water for augmenting streamflow in Grand County;
• $2 million for improving water quality in Grand County;
• $2 million for stream modifications to improve aquatic habitat in Grand County; and
• a partnership with Boulder and Lafayette to provide 5,000 acre-feet of storage space in an enlarged Gross Reservoir to improve aquatic habitat in South Boulder Creek.

Denver Water, Grand County, the cities of Boulder and Lafayette, environmental groups and others still are discussing the proposed environmental enhancements, which go far beyond what the U.S. Army Corps of Engineers requires for mitigating impacts caused by the Moffat Collection System Project. Though the parties have not yet agreed on all the enhancement projects, Denver Water is committed to enhancing the watersheds affected by the Moffat Collection System Project.

The additional water would be carried through the existing Moffat Tunnel from the Fraser River and Williams Fork River basins in Grand County, as well as water from the South Boulder Creek basin. Streamflow in the Fraser and Williams Fork rivers and the South Boulder Creek would be decreased by the Moffat Project only during wet and average years during the runoff months (primarily May, June and July). Possible impacts will be extensively reviewed in the Draft Environmental Impact Statement.

Denver Water currently is involved in two federal regulatory processes to review the proposed Moffat Collection System Project:

• Amendment to the Federal Energy Regulatory Commission (FERC) Gross Reservoir hydropower license
• Application for a Clean Water Act Section 404 permit with the U.S. Army Corps of Engineers (Corps) 

Both processes require an Environmental Impact Statement (EIS), which is being prepared by the Corps as “lead federal agency” and the FERC as one of the “cooperating agencies.”

Both documents (Denver Water’s draft FERC license amendment application and the Corps’ Draft EIS) are available for public review and comment. 

FERC Process

Denver Water operates a hydroelectric power plant at Gross Reservoir under a FERC hyropower license. To enlarge the reservoir, Denver Water needs to apply to the FERC for an amendment to its existing hydropower license. Denver Water is required to provide information on the proposed changes at Gross Reservoir to stakeholders (e.g., relocation of recreation facilities, changes in hydropower generation, etc.), and gather comments prior to submitting a final application to the FERC. Denver Water began the hydropower license amendment process in 2008, and contacted interested agencies and stakeholders to provide information, conduct a site tour, and gather comments.

In preparing the draft FERC hydropower license amendment application, Denver Water considered the comments it received from stakeholders and agencies. The Corps’ Draft EIS contains most of the information that is needed to support the draft FERC hydropower license amendment application. Therefore, the applicable sections of the Draft EIS are referenced in the draft FERC hydropower license amendment application. These documents will be released on Oct. 30, 2009, which will begin a comment period for both the FERC and Corps documents.

EIS Process and Section 404 Permit Application

The Moffat Collection System Project requires a Section 404 permit from the Corps. In 2003, Denver Water initiated the Section 404 permit process with the Corps for Moffat Project. Before making a decision on the permit, the Corps must prepare an EIS to evaluate the direct, indirect, and cumulative effects of the Moffat Project and alternatives. In order for the comment periods to coincide, Denver Water will release the draft FERC hydropower license amendment application at the same time the Corps issues the Draft EIS.

Next Steps

FERC Process

Copies of the draft FERC hydropower license amendment application and the Corps’ Draft EIS will be available for public review at:

• Denver Water’s Web site — electronic copy of the draft FERC hydropower license amendment application will be available and a link to the Corps’ Website and the Draft EIS
• Denver Water Administrative Building (1600 West 12th Ave., Denver, Colorado, 80204) — hard copy
• Local libraries — hard copy
• Denver Water will provide an electronic copy on CD of the draft FERC hydropower license amendment application, if requested

FERC Comment Period:

The agencies and stakeholders are provided several days to provide written comments to Denver Water on the draft FERC hydropower license amendment application. Comments are due by: March 17, 2010.

This comment period coincides with the comment period in which written comments can be made to the Corps with regard to the Draft EIS and the Section 404 permit application. Therefore, all comments concerning the draft FERC hydropower license amendment application shall be made to Denver Water, while all comments concerning the Draft EIS and the Section 404 permit application shall be made to the Corps. All comments on the draft FERC hydropower license amendment application must be submitted in writing to Denver Water through the Denver Water Web site or by e-mail, mail or fax:

EIS process

Copies of the Draft EIS will be available for public review at:

• Corps’ Web site: https://www.nwo.usace.army.mil/html/od-tl/eis/moffat-eis.html — electronic copy
• Corps’ Denver Regulatory Office (9307 S. Wadsworth Blvd., Littleton, Colorado, 80128) — hard copy
• Denver Water Administrative Building (1600 West 12th Avenue, Denver, Colorado, 80204) — hard copy
• Local libraries — hard copy

EIS Comment Period:

The EIS public comment period is from Oct. 30, 2009 to March 17, 2010. This comment period coincides with the comment period for the draft FERC hydropower license amendment application. Written comments are due by: March 17, 2010.

The Corps will hold a series of public hearings on the Draft EIS for public comment at these locations on the following dates:

The EIS is a Corps document; therefore, written comments regarding the Draft EIS and the Section 404 permit application must be submitted directly to the Corps and not to Denver Water. Denver Water encourages the agencies and stakeholders in its FERC hydropower license amendment application process to also participate in the Corps’ comment period on the Draft EIS. All written comments on the Moffat Project Draft EIS must be submitted in writing to the Corps by e-mail, mail or fax:

If approved, construction of the Moffat Collection System Project is estimated to take four years and finish by 2016.

Denver Water’s Web site provides detailed information about the Moffat Collection System Project. For specific questions, send us an e-mail. You also can sign up to receive e-mail updates as the project progresses.

Yes. Denver Water believes stakeholder and public input is important to this process. Denver Water and the U.S. Army Corps of Engineers (Corps) will provide updated information and hold community meetings as the process moves forward and also will provide notices of opportunities for public input.

Comments on the Moffat Collection System Project Draft Environmental Impact Statement must be submitted in writing to the U.S. Army Corps of Engineers by March 17, 2010:

Comments for the draft FERC hydropower license amendment application must be submitted to Denver Water by March 17, 2010: