Many entities compete for Colorado's water resources for various uses. These entities need water at different times of the year. Streams have peak runoff flows from snow melt in May and June; to capture this water, storage water rights are obtained that allow for the storage of water in reservoirs until the water is needed. For example, agricultural demand for water is typically only from May to October. Municipal water demand is fairly constant throughout the year for indoor use but greatly increases for outdoor use in the summer months to water landscaping. Environmental and recreational flow requirements vary by species and recreational activity. The graphic at right (from Headwaters Magazine, The Energy Issue, p.12) shows statewide water withdrawals.
Of primary interest is the consumptive use of water. Consumptive use is the amount of water that is permanently withdrawn from its source because it has evaporated, has been transpired by plants, incorporated into crops or it is directly consumed by people, livestock and industries. Water that is diverted for municipal, industrial or agricultural purposes that is not consumed returns to rivers and/or aquifers by surface flows or underground flows. These surface and underground flows are collectively called return flows and can be used by downstream water users. Water that is diverted from other basins, such as the Colorado River, can be 100% consumed. Specific requirements may be in place for certain transbasin diversions. For example, Colorado-Big Thompson (C-BT) transbasin diversions are single-use; this ensures that entities in the Northern Water (the administrator of C-BT water) service area benefit from return flows.
Statewide, 89% of consumed water goes to agriculture, 7% goes to municipalities and about 4% goes to large industries (Citizen's Guide to Colorado Water Conservation, p.3). Note that this is consumed water, not total water withdrawals as shown in the graphic at right. Withdrawals are generally equivalent to diversions.
However, while agriculture consumes the most water, the U.S. Geological Survey has estimated that approximately only 37% of the water diverted statewide for agriculture is actually consumed (Citizen's Guide to Where Your Water Comes From, p.12). Irrigation return flows are often reused multiple times. Because of this repeated reuse of water, the annual diversions in a river basin can be multiple times the natural water supply.
A water right that was originally decreed for one use, such as agriculture, can be transferred to other uses, such as municipal supply. In this case, the consumptive portion of a water right can be transferred and historical return flow patterns must generally be maintained. Some storage is typically required to assure timing. Transbasin diversions that are returned from wastewater treatment plants are also an important source of water to meet requirements.
Pumping of alluvial groundwater for urban and agricultural uses can remove water from the river and leave senior surface water users with less water than they had previously. In these situations, engineering plans called "augmentation plans" are required to ensure that water extracted from groundwater wells does not unfairly take water from surface water users or senior well users. These plans must be approved in a water court. Permits for new wells are frequently denied unless they also contain an augmentation plan (Citizen's Guide to Where Your Water Comes From, p.17).
There are 117 municipalities in the South Platte and Metro Basin. Collectively, the South Platte and Metro Basin is the most populous basin in Colorado. Approximately 85% of Colorado's population resides in the Front Range. By 2050, the Basin's population may nearly double from approximately 3.5 million people to 6 million people (CWP, p.3-12).
The 10 largest cities in the Basin, based on 2016 population data, from largest to smallest, are: Denver, Aurora, Fort Collins, Lakewood, Thornton, Arvada, Westminster, Centennial, Boulder and Greeley (see next page for population numbers). Each contains over 100,000 people. Except for Colorado Springs and Pueblo, these are also the largest cities in the State (Colorado Springs is the second largest city; Pueblo is the ninth largest).
In this map, municipalities are color-coded by 2016 population and sized by the percent change in population from 2006 to 2016. The greatest percentage changes in population since 2006 are those municipalities in the northern Front Range and include Firestone, Frederick, Johnstown, Mead, Severance, Timnath, Wellington and Windsor. These municipalities may have undeveloped water supplies (own water rights but have not used them) or may seek new supplies from various sources.
Historical population trends and projections are important to understand because more people generally translates to overall higher water demand. (Water use efficiency is discussed in a later section).
This map shows municipal population from 1980 to 2016. Click the "Play" button on the lower-left side of the map to automatically move through the years. Municipalities are color-coded by population and sized by percent change since 1980.
The table below shows the 2016 population (the most recent year of available data) for each municipality in the Basin, as well as the percent of the total state population (5,538,180) and the cumulative percent of the state population. Note that the cumulative percent does not total 85% as stated in the previous page.
Source: Department of Local Affairs State Demography Office, County and Municipal Population Time Series 1980-2016.
Population growth is the single largest driver of the need for additional water supplies in the South Platte River Basin (BIP, p.1-17). Water providers and agencies typically plan for water demand and supply using a long lead time because of long timelines for project implementation.
The Department of Local Affairs (DOLA)'s State Demography Office provides population projections to the year 2050 for each of Colorado's counties. This choropleth map shows county populations for the years 2018 to 2050. Click the "Play" button on the lower-left side of the map to automatically move through the years. (Source: Department of Local Affairs State Demography Office, Population Forecasts - years (2000-2050), 1 year increments.)
As part of the Colorado Water Plan, five planning scenarios were developed that represent how the State's alternative water futures may look in 2050. The scenarios are based on drivers such as population, land use, climate predictions, social values, etc., and are intended to bracket possible growth scenarios. These scenarios are described briefly below in terms of how population may affect water supplies (Colorado Water Plan, p.6-7).
The SWSI Update is incorporating these planning scenarios into its estimates of the water supply gap in 2050. It is not currently understood how the Update will use the population projections quantified by DOLA.
Most residents of Colorado get their water via a water provider entity. The provider may be a municipal utility, a special district, a private company or other entity type. Municipal utilities are often organized as enterprise funds that have independent budgets from the general fund of the municipality, are not-for-profit and balance rates with cost of operations and capital projects. A special district is local government entity formed to serve a single purpose, such as a water and sanitation district.
Municipalities are often served by multiple water providers. They may also have separate utilities or providers for wastewater and stormwater that have different service areas and rates.
Municipal water providers often have a water supply that comes from multiple sources, such as rivers, storage reservoirs, groundwater, transbasin diversions or reusable water. This ensures a reliable supply when one source is not available or has a lower quality.
Municipal water providers generally have a board of directors and hold public meetings. Water-related programs, such as conservation, agricultural water rentals and public education vary by entity type, size and relationship to other municipal programs.
Large water providers are required by federal law to annually publish a water quality annual report or "Consumer Confidence Report" (CCR). These are often available on the water provider's website under headings related to water quality.
House Bill HB10-1051 was adopted by the Colorado General Assembly in 2010 and requires retail water providers that sell 2,000 acre-feet or more of water annually (termed covered entities) to report water use and conservation data on an annual basis. The goal is to improve the quantity and quality of data available that support statewide water supply planning efforts. The data are publicly available from the Water Efficiency Data Portal.
The Colorado Water Conservation Board (CWCB) was directed to develop reporting guidelines that include descriptions of customer categories, uses and measurements. The CWCB determined that the majority of water distribution systems could be classified as Potable Treated Water, Non-Potable Raw Water and Non-Potable Reuse (or Reclaimed) Water.
Within these categories, water use is designated as distributed or metered. Distributed water is the amount of water delivered to served customers. Metered water is the amount of distributed water that is metered by a provider and is calculated as distributed water minus water loss (Distributed - Loss = Metered). Water loss may occur for several reasons, including leaky pipes.
This map shows distributed potable treated water use for covered entities in the Basin for the years 2013-2017. (Note that many of the entities have not submitted 2017 data as of the last download of this data in March 2018). Water providers are color-coded by the population served and sized by the amount of water used.
Potable Treated water is then broken down into customer classes and categories typically include: Residential (Single Family and Multi-Family); Utility/Municipal Facility; Commercial, Industrial and Institutional; and Irrigation Only. Additionally, Wholesale water includes water sold by the reporting entity to another entity for resale to water users (customers). Future versions of this map may break down water use into customer classes.
The image below, from the Citizen's Guide to Colorado Water Conservation (p.3) shows that statewide, the largest municipal water use is residential, and that usage is roughly equal for indoor and outdoor purposes.
Water Conservation vs. Water Efficiency: these terms are often used interchangeably but have different meanings. Efficiency is using the least amount of water necessary to achieve a result and focuses on reducing water waste. Conservation is the act of increasing efficiency and refers to methods that provide permanent water savings or a reduction in the amount of water consumed.
Cities in the South Platte and Metro basins are national leaders in water conservation and reuse (BIP, p.1-17). Municipal conservation programs have already been heavily implemented in the larger cities. This map shows water providers that have published water efficiency plans and pop-ups provide links to those plans. According to Colorado's Water Conservation Act of 2004, water providers that deliver at least 2,000 acre-feet of water per year to their customers are required to file a water efficiency plan with the Colorado Water Conservation Board (CWCB). The CWCB provides Water Efficiency Grants to eligible entities to develop water efficiency and drought plans, implement water conservation goals and educate the public about water conservation.
Water conservation is further categorized as passive or active conservation. Passive conservation is conservation that occurs through natural trends, such as the replacement of older household fixtures (toilets, showerheads, dishwashing machines, clothes washers) with new water-efficient models. Active conservation consists of programs that proactively drive change and require a customer's participation. These include rebates, audits and leak detection, among others. It has been estimated that 160,000 to 461,000 acre-feet of water could be saved statewide by 2050 through active municipal conservation measures and 154,000 acre-feet of water saved through passive conservation measures (Citizen's Guide to Colorado Water Conservation, p.2)
Additional reuse of water supply components including nontributary groundwater, the consumptive use component of changed native water rights and transbasin imports is possible but may affect downstream water availability, water management flexibility and interstate water compact compliance (BIP, p.1-17).
Colorado WaterWise, a non-profit organization, has information about resources for the efficient use of urban water.
This map shows the 500 ditch service areas in the Basin. The largest, FRICO (Farmers Reservoir and Irrigation Company)/ Barr Lake Ditch, serves an area of over 100,000 acres. Service areas are not typically fully irrigated. Some areas within the service area may have been dried up, water rights transferred to urban use or perhaps were never irrigated because of the land use type. Ditch service areas cover many Front Range areas that are now urbanized. The water rights for these ditches are often transferred to municipal water providers, in which case ditch company board positions may be filled by municipal water providers.
To divert water from a river into a ditch or canal for agricultural use (or urban use), diversion structures called headgates are installed in the river. Headgates are typically metal gates that are raised and lowered to allow a controlled amount of water to flow into a ditch or canal. The amount of diverted water is measured and data are maintained by the Division of Water Resources. Ditches and canals often require a dam or inlet structure on the river to help push water into the ditch or canal. Canals and ditches move diverted water using gravity; they often follow the topography of the land and may wind for many miles to their final point of delivery. At certain points along a ditch or canal, additional headgates release water into smaller ditches called laterals or else into pipelines (Citizen's Guide to Where Your Water Comes From, p.26-27). Ditch rights of way may be used for trails and open space; urban ditches may deliver raw water to parks and natural areas.
Most ditches in Colorado are owned by the water users themselves. Small ditches are often owned in partnership by a handful of users. Medium and large ditches are often owned by shareholders of mutual ditch companies, which are private, non-profit organizations formed to distribute water to their member-owners. Owners generally pay a fee to the ditch company based on the share of water that they own. Shareholders also pay annual assessments to cover the costs of operations and maintenance (Citizen's Guide to Where Your Water Comes From, p.27).
The Ditch and Reservoir Company Alliance (DARCA) provides resources for ditch and reservoir companies, irrigation districts, laterals and private ditches.
Agricultural land use has been changing over time for a number of reasons, including:
When agricultural lands are converted to urban use, the term "buy and dry" is often used. This refers to a municipal water provider purchasing agricultural water rights and transferring the consumptive use portion of the right to municipal use. Quite often this process involves storing the water in a reservoir, and perhaps transitioning over time by using rental programs and other options to allow farming to continue. Return flows must be maintained at historical averages as if the land were still in agricultural production. Municipal entities typically don't need the water every year but are purchasing water to plan for growth and as an insurance policy against drought and climate change.
The image on the right shows how agricultural land use has changed over time at the boundary of irrigated agriculture and urban area, in this case near Greeley. Click on the arrows in the middle of the image to move from an image from 2005 to one from 2017. Note the adoption of sprinkler irrigation over time and urban growth onto agricultural areas. Whether the water that was used for agriculture can fully supply urban growth depends on the land use practices of the urban growth.
The impacts of urban growth on irrigated lands in Colorado are illustrated in these Colorado Irrigated Acreage visualizations.
Because agriculture is the dominant water user in the Basin, it is a common perception that if agricultural entities did a better job of conserving water then the anticipated gap in future water supplies could be met. One of the ways in which water can be conserved is through the use of more efficient irrigation systems, such as center pivot sprinklers or drip irrigation.
There are several reasons to switch to more efficient irrigation methods (Colorado Ag Water Alliance (CAWA) Brochure):
The image at right shows the changes in irrigated acreage in the Basin. Each circle represents a diversion structure and is color-coded by the water district it is in. The x-axis represents the number of irrigated acres and the y-axis represents the number of acres irrigated by sprinklers using surface water and groundwater (circles at the bottom of the y-axis therefore represent flood irrigation). Circles are also sized by the percentage of acres irrigated with groundwater. To run the visualization, mouse-over the image at right and then click on the link in the popup. Key observations include:
For more detail on how to use the visualization, click on the Documentation tab within the visualization.
The table below shows the changes in flood- versus sprinkler-irrigated acreage from 2005 to 2015 for several crops in the Basin. Note that the total amount of irrigated acreage has declined by approximately 20,000 acres.
|2005 Acreage||2015 Acreage|
|Barley||No data||No data||3,812||1,275|
|Orchard without Cover||1,298||72||No data||No data|
|Potatoes||No data||No data||147||568|
|Sod Farm||2,148||6,044||No data||No data|
|Sorghum Grain||No data||No data||3,107||2,845|
|Sunflower||No data||No data||1,643||2,220|
|Spring Wheat||No data||No data||35,086||38,808|
Source: Division of Water Resources, GIS Data Library Division 1 Irrigated Lands 2005 and Division 1 Irrigated Lands 2015.
The Colorado Ag Water Alliance (CAWA) is composed of agricultural leaders committed to the preservation of agriculture through the wise use of water resources. Members represent major facets of production agriculture (such as the Colorado Corn Growers Association, Colorado Dairy Farmers and Colorado Cattlemen's Association), as well as partner organizations such as the Colorado Water Institute, Colorado State University, Colorado Department of Agriculture and the Colorado Water Conservation Board.
The primary means of protecting environmental and recreational attributes is through the protection of flows. A range of flows are generally needed to protect aquatic species and their associated habitats. For example, minimum flows are the minimum amounts of water needed to preserve the aquatic environment, whereas peak flows can be cues for fish to spawn, flush sediment and deposit sediment to create new habitat.
The Colorado Water Conservation Board's Instream Flow Program is tasked with the "appropriation, acquisition, protection and monitoring of instream flow and natural lake level water rights to preserve and improve the natural environment to a reasonable degree". This map shows CWCB decreed instream flow reaches in the South Platte and Metro basins. Selecting a month on the right side of the map shows the decreed flow amounts for each month of the year. Hover over a stream reach to obtain more information, such as the number of miles of stream that are protected.
Instream flow rights are often junior to water rights that provide water supply for agricultural and municipal uses and therefore streams with instream flow rights can completely dry up. In other cases, a senior water right lower in a basin can draw water through a reach and help provide instream flow. The nonprofit Colorado Water Trust is an organization that helps improve flow conditions within the water rights system.
Entities do exist that provide stewardship, conservation or other services to protect and enhance environmental attributes. The Colorado Watershed Assembly maintains a directory of watershed groups. Other entities include The Nature Conservancy, Ducks Unlimited and Trout Unlimited, among others. Additionally, The Greenway Foundation specifically focuses on efforts to reclaim the South Platte River and its tributaries.
Additionally, the Open Water Foundation, in coordination with the CWCB, created this interactive visualization of watershed plans in Colorado. The State is divided into Hydrologic Unit Code (HUC) 8 watersheds and the number of plans in each watershed is indicated. By choosing a watershed ("Select Basin" dropdown), it is possible to view the names of watershed plans, who wrote them (Organization), and links to the plans. Many of the organizations are local river coalitions whose missions are to protect and/or restore their local watershed. The dataset for this visualization could be updated to provide additional resources and planning areas can be overlaid with stream reaches.
The South Platte Basin has the highest concentration of watershed plans in this dataset.
This visualization can also be viewed here.
Industrial entities may also be large water users, especially in some areas. Industries may receive water from utilities and other water providers or may provide their own water as a "Self-Supplied Industry (SSI)". Examples of industries that require water, with potential data sources, include:
Increasing water use efficiency in industry can help reduce statewide water demand. Reducing water input to industry also reduces costs to the industry.
This Water Entities story has been created during the South Platte Data Platform Project. This story and all of its content can be found at the swsi-story-sp-entities repository on GitHub. See the README file in the repository for an explanation of data sources and processing.
Additional information can be found at the following:
Questions or feedback? Contact Lacey Williams (firstname.lastname@example.org).
Last update: October 15, 2018
This story is designed to provide information in one-page sections, each of which should fit within the web browser page. To move forward or backward in the story, use the following options:
Additional instructions for viewing the story include:
Interactive graphs typically behave as follows: