Water Supply Fact Book

DisclaimerInformation in this booklet is intended solely for the use of Aurora Water. The user is cautioned that facts are intended to be general information and are not to be used or interpreted as official operational data. Water rights information is general and is not intended as an interpretation of court decrees.

15151 E. Alameda ParkwaySuite 3600Aurora, CO 80012

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Table of ContentsGeneral Information ............................................................................2Organization ........................................................................................4Service Area ........................................................................................4Water Supply Map .......................................................................... 4-5Collection System Map ................................................................... 6-7Major Reservoirs Table ........................................................................8Colorado and Upper Arkansas River Basins ........................................9Lower Arkansas River Basin ...............................................................11Upper South Platte River System ......................................................14Leasing ..............................................................................................16Prairie Waters ....................................................................................16Aurora’s Water Supply System Within City Limits .............................16Treatment Facilities ...........................................................................18

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Colorado is a headwaters state, with the majority of the state’s rivers beginning high in the Rocky Mountains as snowmelt. One of the benefits of living in a state that relies primarily on this surface water is that unlike groundwater, surface water is a renewable water source. Replenished each year through snowmelt, Aurora’s water supply is transported from 180 miles away through a complex and extensive system.

One of the drawbacks of relying on surface water is that precipitation levels vary greatly from year-to-year making the majority of the state’s water supply relatively unpredictable – and highly prone to drought.

Each spring, the snowmelt either evaporates into the air, seeps into the ground or flows as surface water runoff into river basins. Aurora’s water supply is derived primarily from the Colorado, Arkansas and South Platte River basins. Aurora does, however, derive a small percentage of water from deep aquifer groundwater wells. Additionally, Aurora’s newest project, Prairie Waters, allows the city to reuse its precious water supplies, increasing the overall yield of the system.

Snowmelt begins in early May and continues through about mid-July. Once runoff begins, the water is captured and stored in our 12 reservoirs and lakes: Homestake, Turquoise, Twin, Spinney Mountain, Jefferson, Strontia Springs, Rampart, Quincy, Pueblo, Aurora, Meredith and Henry. Following runoff, storage levels decline throughout the remainder of the year, as the city uses the water at a rate greater than any inflow to reservoirs.

Aurora has more than 156,000 acre feet (a.f.) of water storage, which, when filled to capacity, is enough to supply the city with water for three years.

General information

Aurora Reservoir

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OrganizationNumber of Employees: 422Operating Expenses: $131.6 million

Service AreaThis map shows Aurora’s potable water service area, whichencompasses 151 square miles.

Pipelines1,864 miles of distribution pipeline1,041 miles of wastewater pipeline375 miles of stormdrain pipeline

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Major Reservoirs

RESERVOIR

AURORA’S CAPACITY IN ACRE FEET

NORMAL STORAGE CAPACITY IN ACRE FEET BUILT

Colorado River Basin25% of Aurora’s water supply

Homestake Reservoir 21,441 43,600 1967

Arkansas River Basin – 25% of Aurora’s water supply

Turquoise Lake 20,000 129,432 1968

Twin Lakes 2,733 141,000 1978

Pueblo Reservoir 10,000 357,000 1975

Lake Henry/Lake Meredith 9,896 48,765 Natural lakes

South Platte River Basin50% of Aurora’s water supply

Aurora Reservoir 31,679 31,679 1990

Quincy Reservoir 2,693 2,693 1973

Strontia Springs Reservoir 700 7,700 1981

Spinney Mountain Reservoir 53,651 53,651 1981

Jefferson Lake 2,313 2,313 1909

Rampart Reservoir 1,295 1,295 1967

The Homestake ProjectThe Homestake Project diverts water from Homestake Creek and a number of its tributaries into the Homestake Reservoir. Homestake is a cooperative effort with Colorado Springs that collects water and then releases it into Turquoise Lake through the 28,500-feet long Homestake Tunnel. Each city is entitled to one-half of the project yield, although Aurora has an obligation to provide the first 2,500 a.f. of its yield to the Pueblo Board of Water Works.

Busk-Ivanhoe SystemThe Busk-Ivanhoe system is jointly owned with the Pueblo Board of Water Works. Water from Ivanhoe Creek is collected and stored in Ivanhoe Reservoir. The system moves water from Ivanhoe Reservoir to Busk Creek, through the Busk-Ivanhoe Tunnel (formerly known as the Carlton Tunnel). Busk Creek then flows into Turquoise Lake where it can be conveyed to Twin Lakes and the Otero Pump Station.

Colorado and Upper Arkansas River Basins

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Columbine DitchAurora partnered with the Climax Molybdenum Company to form the Fremont Pass Ditch Company and acquire the Columbine Ditch from Pueblo Board of Water Works. The Columbine Ditch is located near Fremont Pass and conveys water from the Colorado River Basin’s Eagle River watershed into the Arkansas River Basin. This water can be exchanged into Turquoise Lake or Twin Lakes.

Turquoise LakeTurquoise is owned and operated by the U.S. Bureau of Reclamation. Aurora has a total of 20,000 a.f. of storage space in the reservoir. Of the water in the reservoir, 15,000 a.f. is from Homestake Reservoir and the remaining 5,000 a.f. comes from other Aurora water rights.

Twin Lakes The Twin Lakes Reservoir and Canal Company project was begun in the 1930s to provide supplementary water to the Colorado Canal, an

RESERVOIR

AURORA’S CAPACITY IN ACRE FEET

NORMAL STORAGE CAPACITY IN ACRE FEET BUILT

Colorado River Basin25% of Aurora’s water supply

Homestake Reservoir 21,441 43,600 1967

Arkansas River Basin – 25% of Aurora’s water supply

Turquoise Lake 20,000 129,432 1968

Twin Lakes 2,733 141,000 1978

Pueblo Reservoir 10,000 357,000 1975

Lake Henry/Lake Meredith 9,896 48,765 Natural lakes

South Platte River Basin50% of Aurora’s water supply

Aurora Reservoir 31,679 31,679 1990

Quincy Reservoir 2,693 2,693 1973

Strontia Springs Reservoir 700 7,700 1981

Spinney Mountain Reservoir 53,651 53,651 1981

Jefferson Lake 2,313 2,313 1909

Rampart Reservoir 1,295 1,295 1967

Turquoise Reservoir

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In the lower Arkansas basin, Aurora has water rights in the Rocky Ford Ditch and the Colorado Canal. Aurora leases 10,000 a.f. of storage in Pueblo Reservoir to hold this water, as well as rights in Henry and Meredith Lakes. This lower Arkansas water is moved up to Twin Lakes through the use of an exchange, from which the water is then moved to Aurora through the Otero Pump Station.

Lower Arkansas River Basin

agricultural irrigation system in the lower Arkansas River valley. Today, shares in the project are owned by various interests, but the majority is owned by Colorado Springs. While Aurora owns five percent of the Twin Lakes project, it is an essential part of Aurora’s water storage system. All of the water collected from the Colorado River and Arkansas River basins travels through Twin Lakes. The water then goes through the Otero Pump Station and into the South Platte River Basin in order to be used by Aurora.

Leadville Ranch Water RightsAurora purchased and transferred the water rights from several ranches near Leadville, CO. The water is exchanged and stored in Twin Lakes or Turquoise Lake.

Otero Pump StationAurora relies on the Otero Pump Station and the Homestake Pipeline to convey water from the Colorado and Arkansas basins to the South Platte River Basin.

The Otero Pump Station, with a capacity of 118 million gallons per day (183 cubic feet per second), is located on the Arkansas River approximately eight miles northwest of Buena Vista. The pump station and pipeline are shared with Colorado Springs. Aurora is entitled to 77.5 cubic feet per second through the Otero Pipeline.

The Homestake Pipeline extends east from the Otero Pump Station through South Park to Colorado Springs. Aurora tees off this pipeline to deliver its transbasin water to Spinney Mountain Reservoir.

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Water Exchanges in the Arkansas RiverThere are two general types of water exchanges: river exchanges and contract exchanges.

River exchanges involve storing water upstream and, in exchange, releasing the same amount of water at a downstream location. River exchanges operate under a complex set of rules and can only be utilized when there are no intervening senior water rights between the downstream and upstream points of exchange. A senior water right means that an entity, such as Aurora Water, was the first to file for water rights. Those who filed afterward receive junior water rights.

Contract exchanges involve two bodies of stored water. One way this is done is water from one reservoir is traded for the same amount of water in another reservoir. Both parties must agree in order for a contract exchange to occur. For example, Aurora and Pueblo Board of Water Works have executed contract exchanges by trading Aurora’s water in Pueblo Reservoir for Pueblo’s water in the Twin Lakes. Contract exchanges are not dependent on river flows, so they can occur any time there is enough water in both storage locations to be exchanged. Because the water does not have to be physically moved from one reservoir to the other, it saves water that might have been lost naturally during the transportation process.

Pueblo ReservoirAurora leases 10,000 a.f. in Pueblo Reservoir from the Bureau of Reclamation on an excess capacity basis. As an excess capacity lease, Aurora’s water is the first to be released when other storage commitments in the reservoir require it. This storage is used to hold Aurora’s rights from the Lower Arkansas River.

Rocky Ford DitchThe Rocky Ford Ditch has an appropriation date of May 15, 1874, making it one of the most senior water rights in the Arkansas River system.

The ditch diverts water from the Arkansas River between Manzanola and Rocky Ford and formerly irrigated 8,000 acres of land surrounding the town of Rocky Ford. The ditch still supplies water to the Colorado State University Research station and a limited amount of irrigated land.

In 1980, Aurora purchased a majority of water rights in the Rocky Ford Ditch, and now owns 93 percent of the shares. These shares have been purchased and converted to municipal use and are divided into two different water right allocations: Rocky Ford I and Rocky Ford II. After diversion for storage at Pueblo Reservoir, the water must be exchanged upstream to Twin Lakes for delivery through the Otero Pump Station.

According to a set diversion pattern, the Rocky Ford I water rights are diverted beginning March 15 through October 1, while the Rocky Ford II water rights are diverted beginning March 15 through October 31.

Colorado Canal and Lakes Henry and MeredithThe Colorado Canal System is comprised of the Colorado Canal Company, the Lake Meredith Company and the Lake Henry Company. The Colorado Canal diverts water from the Arkansas River near Boone, downstream of Pueblo. The Colorado Canal conveys water either directly to agricultural water users or for storage in Meredith and Henry lakes. Stored water can then be released from Meredith and Henry lakes to be exchanged upstream for use by municipal and

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The other half of Aurora’s mountain water supplies comes from the upper South Platte Basin, from farms and ranches in Park County. Aurora also has Spinney Mountain Reservoir and Jefferson Lake in the upper South Platte. Closer to town, Aurora uses Strontia Springs Reservoir to move mountain supply out of the river. Water is transported to Rampart Reservoir and then, through a series of pipelines, to Aurora’s three water purification facilities and to Quincy or Aurora reservoirs.

Spinney Mountain Reservoir Spinney is Aurora’s largest reservoir and is located 23 miles southeast of Fairplay in South Park. Water rights in the South Platte River Basin are stored in Spinney Mountain Reservoir for subsequent release to Strontia Springs Reservoir and delivery to Aurora. In addition to native flows, water in Spinney Mountain Reservoir is imported from the

Upper South Platte River System

industrial shareholders. In addition, releases can be made from the reservoirs and exchanged back to the Colorado Canal for use by the agricultural shareholders. All shareholders must physically divert water through the Colorado Canal and then exchange the water upstream in accordance with decreed water rights. There is no alternate point of diversion located in upstream facilities.

Shares of the Colorado Canal system are mostly owned by municipal and agricultural entities. Colorado Springs is the majority shareholder, while Aurora owns approximately 27 percent.

Holbrook ReservoirDownstream from Pueblo Reservoir, there is a whitewater kayak park. To help protect the water flows and keep the park operational, Aurora has agreed not to divert the Rocky Ford water rights in Pueblo Reservoir when the water levels at the kayak park drop too low. Instead, Aurora attempts to recapture the same amount of water downstream in the Holbrook Reservoir and then exchange it back upstream when the river conditions allow it or the opportunity exists.

Arkansas River and Colorado River Basins via the Otero Pump Station and the Homestake Pipeline (transbasin diversion).

Middle Fork South Platte Water RightsTransferred agricultural water rights from the Middle Fork South Platte River Basin above Spinney account for a significant portion of Aurora’s supply in the South Platte River Basin. Aurora began acquiring Middle Fork basin water rights in the late 1960s.

Tarryall Creek BasinAurora also owns transferred agricultural water rights in the Tarryall Creek Basin, a tributary of the South Platte River. That water is stored in Strontia Springs Reservoir and is subsequently released to Rampart Reservoir.

Strontia Springs Reservoir SystemStrontia Springs Reservoir is owned by Denver, and Aurora leases 700 a.f. of storage space. All of Aurora’s Upper South Platte water rights and transbasin water rights are delivered to Strontia Springs Reservoir prior to final delivery to the city.

Strontia Springs Reservoir is located approximately six miles upstream of the mouth of Waterton Canyon on the South Platte River.

Rampart Reservoir SystemThe Rampart Reservoir and Dam is located in Douglas County near Waterton Canyon. This reservoir is a small regulatory reservoir that is filled through a tunnel and pipeline system from Strontia Springs Reservoir. The Rampart Pipeline delivers water to Aurora from Rampart Reservoir.

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All of Aurora’s mountain supplies are delivered to the city via the Rampart Pipeline. Water is delivered to one of Aurora’s three water purification facilities or to Quincy or Aurora reservoirs for storage.

Aurora also uses both shallow alluvial wells and deep aquifers. Aurora’s largest and oldest well field is the Cherry Creek well field, constructed in 1956. Water from the well field is piped to the Griswold Water Purification Facility for treatment. Well water makes up less than five percent of Aurora’s water supply.

Aurora’s Water Supply System Within City Limits

Prairie Waters is an innovative system that uses a sustainable water source by recapturing river water.

Using both natural cleansing processes and state-of-the-art purification technology, it is designed to deliver an additional 3.3 billion gallons of water per year, or 10,000 a.f.

Aurora’s available water is first pumped from wells through hundreds of feet of sand and gravel to clean out impurities. The water is then moved more than 34 miles through three pumping stations before it is treated at the Peter D. Binney Water Purification Facility, north of Aurora Reservoir.

Prairie Waters

Because such a large portion of Aurora’s water supplies are dependent on highly variable snowmelt runoff, there are times of drought and times of abundance. When Aurora has excess supplies, they can be leased to others, which can help stabilize Aurora’s water rates. Our top priority is ensuring we have adequate supplies for residents, so we have to plan our water supply system to meet demands during droughts. During those times, we also have the possibility to lease water from others.

Leasing

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ConservationFor decades, Aurora Water has actively encouraged the efficient use of water. Established in 1980, our Water Conservation Division has a host of programs and financial incentives designed to help residents conserve water. Water Conservation staff offers rebates for water efficient appliances and water-saving xeric landscapes, provides free classes on ways to save water and conducts free automatic sprinkler system audits. Staff also works with car washes, industrial users, hotels and others, so businesses can also find ways to save water.

The conservation division’s youth education program includes classroom presentations and the annual Youth Water Festival, a celebration and educational event for fifth graders.

As a result of the conservation division’s efforts – and Aurora residents’ commitment to save water whenever they can – per-capita water usage has declined 20 percent since 2002.

While significant water savings have been made, Aurora Water will continue to promote the efficient use of its water resources and to achieve savings wherever possible.

ReuseUnder Colorado Water Law, approximately 90 percent of Aurora’s mountain supplies, as well as all agricultural rights from the lower South Platte, are fully consumable or reusable to extinction. Essentially, that means that the water residents use eventually makes its way back to the South Platte River Basin for use again and again. That water is referred to as return flows.

In practice since the late 1960s, a portion of this water is sent to the Sand Creek Water Reclamation Facility, which delivers non-potable water for irrigation at some city parks, golf courses and medians.

Whatever return flows that are not used directly for irrigation through the Sand Creek facility remain in the South Platte River. Aurora then has the ability to recapture these return flows through the Prairie Waters Project.

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Treatment FacilitiesGriswold Water Purification FacilityOn-line since 1967, the facility can treat up to 80 million gallons per day.

Wemlinger Water Purification FacilityBuilt in 1982, the facility can treat up to 80 million gallons of water a day from Rampart and Aurora reservoirs.

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Griswold Water Treatment Plant

Peter D. Binney Water Purification FacilityOpened in 2010, the 70-acre, state-of-the-art facility uses ultraviolet oxidation, as well as activated carbon filtration, to destroy unwanted contaminants. It is one of the most advanced water purification processes in the country. The facility can treat up to 50 million gallons of water each day.

Sand Creek Water Reclamation FacilityBuilt in the early 1970s, the facility was one of the first reuse facilities built in Colorado. It produces up to five million gallons of non-potable water per day.

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