Text Size

Site Search

Alt. Water Transfers

Cover HW Fall 2017

Water sharing and banking, coined "alternative transfer methods" or ATMs, could provide flexibility for stretched water supplies —but not without marked challenges. Read the Fall 2017 issue of Headwaters magazine and explore options to:

  • keep water in farming
  • help municipalities plan ahead
  • share between ag and environmental uses
  • bank water on the Colorado River

Browse articles and find a flipbook of the magazine here.

Connecting the Drops

connectingdropslogo4.1Bringing you the reporting you crave over the radio airways with extras and archives on our website. Visit the audio archives or listen to the latest story on the National Wild and Scenic Rivers Act and the Colorado river that could become the state's second wild and scenic protect river—Deep Creek:

Deep Creek 5 web

Water Education Colorado

Webinar Attendees Mailing List Sign-Up

Thank you for attending the Paying for Colorado's Water Future Webinar!  Click here to sign up for CFWE's e-newsletter and to receive Headwaters magazine.

Save the Date: Yampa Basin Tour

Mark your calendar and save the date for June 11-13 to join CFWE's annual river basin tour adventure!

We'll gain first-hand experiences learning about river recreation, agriculture, ecological health, future water demands and more in Northwestern Colorado's Yampa Basin. Tour with a diverse group of elected officials, decision makers, water professionals, interested citizens and many others to gain access to exclusive sites and expert speakers. Download the draft itinerary and get ready to register to see, experience and hear from:

  • Elkhead Reservoir
  • Craig Power Plant
  • Carpenter Ranch
  • City of Steamboat Springs
  • Stagecoach Reservoir
  • Finger Rock Preserve
  • And others along the way!


Read more: Save the Date: Yampa Basin Tour

Network Goals

The Water Educator Network aims to build the capacity of local water educators, and thereby increase the amount, quality and effectiveness of water education in Colorado communities. Strong and effective water education programs have the potential to grow the knowledge, change the attitudes and increase the involvement of tens of thousands of Colorado youth and adults annually. This will lead to a more active and involved citizenry that advocates for balanced, sustainable solutions. The Water Educator Network accomplishes this through the actions below. Read more about the Networks goals and first year of accomplishments here

Central Repository of Information

Search for and share water education resources! CFWE has partnered with the Colorado Alliance for Environmental Education to create a Water Educator Network portal on their resource directory. Water Educator Network members can add and update their respective programs plus connect with related resources. Browse the directory here.

Customized Communication

Members can look forward to semi-monthly e-newsletters related to best practices and proven curriculum in water education, upcoming funding opportunities, trainings, tips, and new or highlighted programs happening around the state. Find the latest here.

Convening Forum

Water Educator Network members benefit from biannual members-only networking events. These forums bring together a statewide group of dedicated educators to discuss their needs, successes and challenges plus form collaborations and partnerships.

Specialized Training

The Water Educator Network will offer professional development opportunities to members by hiring expert consultants to deliver quarterly in-person trainings and webinars. Initial topics include understanding and interpreting technical water resource issues, community event and water festival planning and program evaluation techniques

NEW Water Educator Network


The Colorado Foundation for Water Education brings you an all new Water Educator Network!

We're improving the understanding of Colorado water issues by increasing the amount, quality and effectiveness of water education. Local water educators will thrive with tools, trainings and collaborations that are relevant to their work, easily accessible and simple to implement. Learn about Network membership benefits and events here or join us for:

July 30: Water Festival Season Debrief 9 am-12 pm at MSU Denver. Learn more and Register here
TBA: "program evaluation" and "working with schools"

Creative and Cooperative Groundwater Strategies

Please update your Flash Player to view content.

Click the Fluent Water Facts above to learn more about Colorado’s groundwater and the challenges it poses.

An All-of-the-Above Strategy
Many communities and water utilities that have relied heavily on non-renewable groundwater supplies have turned to a number of options to reduce this use. Some of their strategies include:

Converting to renewable water supplies – Some communities hope to use surface water, in rivers or reservoirs, to augment their groundwater supplies. This is often difficult, as many surface water supplies already have more claims on the water than water available. Some of the new rights might also be too junior – too low in the prior appropriation system – to supply enough water, especially in dry years.

Transbasin diversions – Water can be moved from basins with more water to basins with less water. This usually involves transferring water from the Western Slope to the Front Range, but not always. These diversions, however, require construction of storage, conveyance systems, treatment plants, and distribution facilities, which is expensive. The diversion might also be unpopular in the basin of origin.

New storage facilities – Even if the water rights can be obtained, building reservoirs is an expensive and lengthy process. Many are also unpopular.

Working with other entities to share storage – Water utilities can share space in existing or future reservoirs, rather than building their own.

Preserving the aquifers – Elbert, Adams, Weld and El Paso counties have enacted a 300 Year Rule, rather than a 100 year rule. If developers are interested in using groundwater, they can only use 0.33% of the calculated water in storage, rather than 1%. Pumping the water at a slower rate should reduce drawdown and ensure longer aquifer life. The amount of water in the aquifer, however, is hard to estimate, so there is no guarantee that it will last three times as long as pumping at the 1% rate.

Transferring agricultural water rights to municipalities – Some farmers are willing to sell their water rights to municipalities, leaving their fields dry. These transfers are often controversial. New laws allow these transfers to be interruptible, rather than permanent sales. Crop rotation is also encouraged. You can read more about these transfers in the Fall 2012 Headwaters.

Water conservation – Many utilities use a variety of incentives to improve water use efficiency, change customer behavior, and reduce demand. Some utilities have introduced tiered rates, where using more water costs more, while others have raised rates. You can read more about these strategies in the Winter 2013 Headwaters.

Using surface and groundwater – Using both sources jointly ensures more reliable supplies than using either on its own. This strategy helps manage short-term shortages and minimizes the need for above-ground storage.

Potable and non-potable water reuse – Non-potable water, which is not suitable for human consumption, may be used on golf courses, parks, and open spaces.

Recharging aquifers – During wet years, surface water is stored for later use by injecting it into groundwater aquifers, rather than storing it in a surface reservoir. Centennial Water District uses this strategy.  The water is not lost to evaporation, as it would be in surface storage, but it must be pumped back up to the surface for use, which takes time and uses energy.

Additional Resource: The South Metro Water Supply Authority adopted a Regional Master Plan in 2007, which guides participating water providers as they reduce their reliance on deep groundwater and expand the role of renewable groundwater in meeting current and future water needs. You can learn more on their website.

Groundwater Supplies

Click the Fluent Water Facts below to learn more about Colorado’s groundwater and the challenges it poses.

Please update your Flash Player to view content.

Hundred Year Honeymoon

Groundwater can take thousands of years to accumulate in aquifers, and some of these aquifers have little connection to replenishing precipitation on the surface – they are essentially considered non-renewable. If humans pump water from these non-renewable aquifers, how long will the water last?

The answer varies from aquifer to aquifer. It is difficult to estimate the amount of water available in any given aquifer. Each year, groundwater measurements throughout Colorado are posted by the Colorado Division of Water Resources. These measurements do not come from dedicated monitoring wells, so the measurement wells vary significantly in age and how they are pumped. The statistics illustrate the variability of aquifers, whose water levels may decline, rise, or stay the same.

Declines in the Denver Basin

Since aquifers are so variable, it is difficult to draw conclusions about the fate of Colorado’s groundwater. Statistics from the Denver Basin illustrate groundwater’s uncertain future.

Between 1990 and 2000, development in the south Denver metro area of northern Douglas County and southern Arapahoe County resulted in aquifer declines from 100 to almost 300 feet. In some parts of the Denver Basin, the most heavily developed aquifers see water level decreases of 30 feet per year. Water levels in the dominant municipal water supply aquifers, the Arapahoe and Laramie-Fox Hills, are not favorable. South Metro businesses and homes may have serious water supply challenges to address in the near future.

Managing a Limited Resource

The potential of exhausting groundwater supplies affects how this resource is managed. Well permits only grant the right to drill for water and pump at the specified rate – they do not guarantee how long the groundwater supply will last. Some groundwater permits require augmentation plans. Although there is significant debate regarding how much water is available in different parts of the Denver Basin, aquifer drawdown and a 100-year aquifer life are central parts of how the state decided to allocate this complex resource.

These groundwater challenges are unlikely to go away. Colorado’s population continues to increase – the population of Douglas County grew 191% between 1990 and 2000, and the state’s population is expected to nearly double by 2050.

Groundwater has traditionally been an attractive source because it has been plentiful, is of good quality, and is inexpensive to produce. As the water becomes less plentiful, and water table levels drop, groundwater will likely become more expensive to tap. It is possible that economic considerations will make groundwater an unattractive alternative before supplies are exhausted. Clearly, managing groundwater supplies will continue to require creative and collaborative solutions.


Groundwater Laws

Click the Fluent Water Facts below to learn more about Colorado’s groundwater and the challenges it poses.

Please update your Flash Player to view content.

Early Colorado Water Law: Focus on Streams

Colorado’s semi-arid climate was a challenge to early American settlers. Growing crops required extensive irrigation networks. Settlers mostly drew their water from streams and rivers. When Colorado became a state, water law was established under the doctrine of prior appropriation, allowing the holders of senior (older) rights to draw water before the holders of junior (newer) rights in times of shortage.

At this time, groundwater use was minimal in most areas. Wells were generally shallow and hand-dug. Windmills pumped limited quantities of groundwater for livestock and homesteads. Throughout the decades, use of groundwater increased, but it was not until the 1950s that new technology, population growth, and drought would combine to push the state’s first set of extensive groundwater regulations into place.

Pressure from Below

Surface rights holders in the South Platte and Arkansas river basins became concerned that wells were pumping water that depleted streams, leaving senior surface rights unfulfilled. Since this groundwater pumping was not administered, as surface water was, senior surface rights holders had little recourse. In response, statutes and court decisions in the 1950s and 1960s required the State Engineer to administer tributary groundwater under the doctrine of prior appropriation.

Regulating Non-Tributary Groundwater

In 1957, the Colorado General Assembly created the Colorado Ground Water Commission for the purpose of examining and possibly regulating critical groundwater areas.

The Commission established eight “designated groundwater” basins in eastern Colorado. Under natural conditions, these basins do not recharge or supplement to any significant degree continuously flowing surface streams. Since these designated groundwater basins do not deplete water from surface streams, they are not administered by the prior appropriation doctrine. They are regulated by the Ground Water Commission, which uses a modified appropriation system to allocate designated water outside of the Denver Basin on a permit-by-permit basis. In the Denver Basin, designated groundwater is allocated to the owners of the overlying land.

Making Non-Renewable Water Last: The 100 Year Rule

In 1973, Senate Bill 213 established how water pumped from deep and potentially non-renewable aquifers should be managed. This bill also set criteria for the State Engineer to follow when issuing well permits in these bedrock aquifers. This established the 100-year pumping rule. Landowners who want to pump groundwater must first receive estimates of how much groundwater can be pumped from that source. Landowners may withdraw water at the rate of 1% of the aquifer resource under their property per year. In theory, this would ensure that the groundwater would last 100 years. In practice, however, there is no such guarantee. Estimates of the amount of water in an aquifer are not precise, so the supply could last more or less than 100 years.

Groundwater Rules for the Denver Basin

In 1985, the General Assembly passed Senate Bill 5, which specifically addresses groundwater in the Denver Basin. Much of this water is considered non-renewable. Since most of this groundwater is non-tributary, pumping it should have little effect on the holders of surface water rights. The Senate recognized, however, that some hydrologic connection may be evidenced over very long time periods. They ruled that not all the water withdrawn from the non-tributary Denver Basin aquifers could be consumed; 2% had to be replaced. Most of this provision is met by return flows from outdoor watering or other sources.

The legislature also recognized that some of the deep Denver Basin aquifers were not completely separated from overlying streams, and were not actually non-tributary. These aquifers received the confusing designation “not-nontributary.” Areas along the South Platte River and Denver streams, including Monument Creek and Cherry Creek, are considered not-nontributary. Users of not-nontributary water must return at least 4% of the water they pump to the surface stream.


Groundwater poses certain unique difficulties of access and management. Digging wells to access this underground resource is an ancient practice. How do people access water far below the surface? How does it affect surface water? What rules govern groundwater? Here are a few key points for successful groundwater use:

Click the Fluent Water Facts below to learn more about Colorado’s groundwater and the challenges it poses.

Please update your Flash Player to view content.

Know Your Rocks

Different types of rock are more likely to yield their stored water. It is easier to extract or drain water out of coarse-grained rocks like gravels or sandstones, because the pore spaces tend to be large and well-connected. In contrast, fine-grained rocks like mudstones, clays and shales yield water at much lower volumes and slower rates, because the smaller, less-connected pore spaces drain less efficiently. Fine-grained rocks yield little water and may even produce impermeable or confining layers separating aquifers.

Dig For It

Wells must reach the top surface of the groundwater, known as the water table. As the wells begin to drain away the water, the water table may shift downwards as the overall volume of groundwater declines. When this happens, deeper wells may be required to reach the new water table level.

Some wells are able to take advantage of artesian pressure, which helps raise groundwater nearer the surface with less pumping. Artesian pressure raises water above the top of the aquifer. In some cases, the water rises above the surface, forming a flowing artesian well. These often occur when recharge areas are several hundred feet higher in elevation than most of the basin, which occurs in the Denver Basin.

More Wells, More Water?

Multiple wells can tap into the same groundwater source. If a neighboring well pumps water at a faster rate, it can drain away the water from the first well. Both well users might then need to dig deeper wells, if water remains low.

Multiple wells can also decrease natural artesian pressure. When water levels decline, larger pumps and motors, as well as increasing energy usage, will be required to withdraw the same amount of water.

You Can’t Claim It All

Tributary groundwater, which is connected to surface streams, follows the same law as surface water – prior appropriation. Water claims with the older, or senior dates, may claim water before those with newer, or junior dates, in times of shortage.

The prior appropriation system cannot work properly in deep bedrock aquifers, which are usually non-tributary and slow to recharge. This is because the prior appropriation system seeks to protect senior rights holders from injury – that is, other users taking water that then does not leave enough water for the senior rights holder’s claim. After the first well starts pumping, all subsequent wells will naturally deplete the first well’s original artesian pressure, creating “injury.” Consequently, deep aquifers follow different laws.

No groundwater is completely non-tributary. If pumping does adversely affect surface streams, water rights holders should be compensated, usually by water being added to the stream through an augmentation plan to fulfill their right.

No Well is an Island

Most groundwater requires replenishment, or recharge, or some kind. Natural recharge occurs when rain or snowmelt works its way through the layers of soil and rock. Recharge can also be accomplished artificially, through specially-designed recharge ponds or injection wells.

Some areas rely on return flows for recharge. Return flows are ground or surface water that returns to rivers and shallow aquifers after being put to beneficial use, such as irrigation. Lawn-watering also produces returns flows for recharge. Increased water efficiency measures, however, may reduce return flows, requiring new sources of water for recharge.

The type of rock influences how long it will take an aquifer to recharge. Precipitation can work its way through the soil quickly, but takes far longer to infiltrate inter-layered sedimentary rocks. Some aquifers are confined by layers of impermeable rocks, and are essentially considered non-renewable.

Colorado's Four Major Aquifers

Please update your Flash Player to view content.

Click the Fluent Water Facts above to learn more about Colorado’s groundwater and the challenges it poses.

Colorado has aquifers, which contain groundwater, throughout the state. Groundwater can be found in many rock formations, and major streams and rivers have accompanying aquifers, although their size and accessibility varies. Below are Colorado’s four major aquifers:

South Platte Aquifer

The South Platte Aquifer follows the South Platte River through northeastern Colorado. This region is heavily populated (70% of Colorado’s population lives there, according to the 2000 Census) and heavily farmed. But the aquifer’s connection to the river means that pumping groundwater affects surface rights.

Type: Alluvial  

Depth: 20 feet under Denver, but depths of 200 feet some 160 miles further downstream; average depth is 36 feet

Used for: Mostly irrigation, but some water for local communities

Challenges:Since the late 1960s, drilling of new wells has been restricted, due to the effects on surface rights. Colorado must abide by the terms of the South Platte River Compact, which requires certain amounts of surface water to be sent downstream. Recharge is heavily influenced by return flows, which mostly come from agricultural users. As the water is used and reused for irrigation, it has higher concentrations of dissolved solids and nutrients, which affect water quality. Discharges of municipal wastewater also affect water quality.

San Luis Valley Aquifers

San Luis Valley aquifers are connected to the Rio Grande and its tributaries, so pumping groundwater affects surface water and its rights holders. The Valley faces critical surface and groundwater shortages.

Type: Alluvial

Depth: 100 feet in the northern part of the valley, 40 feet in the southern portion

Used for: Vast majority for irrigation for farms, but some drinking water for local communities

Challenges: Aquifer levels have been steadily dropping. Natural recharge is difficult, as the San Luis Valley receives 7-8 inches of precipitation a year, half of Colorado’s state average. Pumping groundwater affects surface water, and Colorado must meet the terms of the Rio Grande Compact, which requires certain amounts of water to be sent downstream.

Read more about the San Luis Valley's challenges in the Summer 2013 issue of Headwaters magazine.

Denver Basin Aquifer

The Denver Basin aquifer system is a major source of water for South Metro Denver. The system extends from Colorado Springs in the south to Greeley in the north, from the foothills near Golden in the west to the eastern plains near Limon, a surface are of about 6,700 square miles. It includes four aquifers: the Dawson, Denver, Arapahoe, and Laramie-Fox Hills. Each aquifer has different water quality, depths, and water availability.

Type: Sedimentary bedrock

Depth: Shallow wells can reach the Dawson aquifer, the shallowest in the system, but other aquifers are a half-mile below the surface.

Used for: Mostly homes and businesses

Challenges: Extensive development in the South Metro area of Denver has resulted in steady and substantial aquifer declines, especially in the Arapahoe aquifer. Some of the water stored in these deep aquifers may be more than 50 million years old. Studies show that it took tens of thousands of years or more for nature to fill this resource. Since much of this groundwater is considered non-renewable, these rates of decline are not considered sustainable.

Read more about the Denver Basin aquifer, its geology and its challenges, in the Citizen's Guide to Denver Basin Groundwater.

High Plains Aquifer

The High Plains aquifer currently supplies water to about 20% of irrigated farm ground in the United States. It is found in parts of eastern Colorado, but the total aquifer underlies about 174,000 square miles from South Dakota to Texas and New Mexico. In eastern Colorado and eastern New Mexico, this is called the Ogallala formation.

Type: Sedimentary bedrock

Depth: Average of 300 feet below the surface

Used for: Mostly irrigation, with relatively little domestic use

Challenges: Since the 1960s, people have been extracting more water from this aquifer than has been returned. Aquifer recharge comes mostly from local precipitation – but the region receives relatively little precipitation and has high rates of evaporation. New conservation strategies have reduced the amount of water pumped, and withdrawal levels appear to have stabilized.

What is an Aquifer?

Please update your Flash Player to view content.

Click the Fluent Water Facts above to learn more about Colorado’s groundwater and the challenges it poses.

Nature’s Underground Water Storage

Aquifers store groundwater. An aquifer is a layer of saturated rock through which water can easily move. Aquifers are everywhere – under the plains, mesas, and mountains. But aquifers vary significantly in the amount of water they hold, their depth underground, and their availability for use by humans. Geology often defines how this water moves and can be accessed.

Aquifers in Colorado are usually one of three types:

Alluvial Aquifers

Alluvial aquifers are generally shallow sand and gravel deposits laid down over time in a river channel or floodplain. The name “alluvial” refers to the loose, unlayered nature of the material – often silt, clay, sand, and gravel, deposited by running water in and around rivers.

Alluvial aquifers are often referred to as “tributary aquifers,” meaning that they exchange water back and forth with surface streams. Major alluvial aquifers surround every large river in the state, and smaller alluvial aquifers surround all the creeks and streams.

Colorado’s alluvial aquifers can supply water to cities and farms, but unless they are managed carefully, they can be over-pumped and/or polluted. If wells pump more water than is returned to an alluvial aquifer, this may mean less water is available in nearby lakes and rivers.

Sedimentary Bedrock Aquifers

Sedimentary aquifers exist deep under ground, primarily in sandstones and limestones. Multiple geological layers and aquifers exist at different depths. Examples of sedimentary aquifers in Colorado include the Denver Basin, High Plains, and Piceance Basin in northwestern Colorado.

These deep aquifers are often confined – rock layers above them have low permeability, which limit the amount of water that can move back and forth to the aquifer. These aquifers are typically not connected to nearby rivers, as alluvial aquifers are, so their groundwater is usually considered non-tributary. Deep aquifers still have recharge areas, but these may be many miles from the aquifer itself. Recharge for deep aquifers requires very long time periods – potentially thousands of years.

Fractured Rock Aquifers

Fractured rock aquifers are common in the mountains. Underneath a layer of soil and loose rocky material, aquifers exist in bedrock full of cracks and fractures created by the natural folding and faulting of the rock over millions of years. These cracks can fill with water supplied by infiltrating snow and rain. Not all fractures contain water, however. Springs can arise where fractures intersect the land’s surface.


Page 1 of 3

Social Media

Stay in touch and connect through:

FB-fLogo-Blue-broadcast-2 Twitter Logo White On Blue instagram    

Sign Up for our e-newsletter

learn more3learn more

 And view the latest issue of Headwaters Pulse, Water Education Colorado's monthly e-newsletter, here.


Click the icons below for videos about climate change, ranching and more; or audio from Water Education Colorado's Connecting the Drops radio series.

filmicon   headphonesicon

1750 Humboldt Street, Suite 200
Denver, CO 80218