Water Terms
Water terms and their associated definitions can be confusing. To help demystify and clarify language that is often used when discussing water in Colorado provided below is a list and definitions of commonly used terms utilized by the Upper Arkansas Water Conservancy District.
Abandonment of Water Rights
Prior appropriation water rights are presumed to have been abandoned if they are not exercised during a 10-year period. The State Engineer compiles a periodic ranking list of active decreed water right priorities and an abandonment list.
Absolute Water Right
A property right to put water to a specific beneficial use, in a specified portion, in accordance with its priority.
Acre-foot (a/f)
A measurement of water. It is the amount of water that will cover an acre of land at a depth of one foot. Think the size of almost a football field!
It is equivalent to 325,851 gallons. An acre-foot typically serves the needs for a family of four for a year.
Adjudication
Judicial proceedings before the State of Colorado Water Court to hear and decide a water rights case.
Alluvial Storage
Below ground water storage. See Trout Creek Park project.
Appropriate
To take the legal actions necessary to create a right to divert water from a stream, tributary or aquifer for application to beneficial use.
Appropriation
The right to take water from a stream or aquifer for beneficial use, at a specific rate or flow. Water courts must issue a decree for the appropriated water.
Aquifer
A water-bearing layer of rock or sediment capable of yielding supplies of water.
Arkansas River Compact of 1948
This compact apportions the waters of the Arkansas River between Colorado and Kansas based on the inflow to John Martin Reservoir during the winter storage season (December 1 to March 31). This water in storage can be released at the demand of either state after April 1.
Augmentation
Supplementing the water supply of a stream affected by well depletion, in order to protect senior water rights on a stream. Augmentation doesn’t put water in the well and is not designed to recharge the aquifer. Click here for more info.
Augmentation Certificate
A document representing the ownership of an augmentation water right.
Augmentation Plan
An augmentation plan is a court-approved plan, which is designed to protect existing senior water rights by replacing water used in a new project. The UAWCD has a blanket augmentation plan and administers replacement water programs for thousands of customers using infrastructure located in the upper reaches of the Arkansas River Valley above Pueblo, and various legal instruments and decrees. Click here for more info.
Basin
A region drained by a single river system. The UAWCD is located in the Upper Arkansas River Basin. There are eight major river basins in Colorado, including the Denver Metro area basin.
Beneficial Use
The basis, measure and limit of a water right. The lawful appropriation that uses reasonably efficient practices to put water to use without waste.
Blue Line
Defines the geographic area of the District's blanket augmentation plan.
Call
The right of a senior water rights holder to “call” for his/her water. Junior water rights holders must pass the water on to the senior holder and not divert until the right is satisfied. Administered by the Division of Water Resources.
Change of Water Right Decree
A water court decree that allows a different type of use, different point of diversion, or different place of use, while retaining the senior priority of the original water right. For example, changing an irrigation decreed water right to a municipal decreed water right. A change of use must be applied for and approved through water court. A change of water right is not required for a simply a change in ownership. Only the historical consumptive use of the water right might be change to a new use, not the historical diversion in order to ensure that no other water rights holders will be injured by the new change of water right.
Colorado Division of Water Resources (DWR)
Also known as the Office of the State Engineer. For over 125 years, the DWR has been empowered to administer all water rights according to the Appropriation Doctrine (in short, 1st in time, 1st in right). Most of this work is done by Division Offices located in the seven major river basins of the state. These offices employ water commissioners to ensure the priority system is followed, enforcing the decrees and water laws of the State of Colorado. The Colorado Ground Water Law of 1957 established the permitting requirement of ground water wells, and by 1969, surface and ground water rights were administered together.
Colorado Groundwater Commission (CGWC)
The regulatory and permitting agency authorized by the General Assembly to manage and control ground water resources within eight Designated Ground Water Basins in eastern Colorado.
Colorado Water Conservation Board (CWCB)
The state agency vested with the exclusive authority to appropriate waters of natural streams and lakes as determined may be required for minimum stream flows and volumes for natural lakes, in amounts that are determined to be necessary to preserve the natural environment to a reasonable degree.
Compact
A contract between states that is ratified by those states legislatures and by the U.S. Congress. The contract controls the division of water in a river system that flows across state boundaries.
Conditional Water Right Decree
A conditional decree holds a date in the priority system which is then finalized when the water is put to beneficial use. Because water projects are often complex and take a long time to complete, this is a helpful tool.
Consumptive Use
Water that is withdrawn through evaporation and transpiration, incorporated into products or crops, consumed by humans or livestock, or otherwise removed from the immediate water environment.
Cubic Feet Per Second (CFS)
A rate of flow for water in a moving stream or diversion. Water flowing at 1 cfs will deliver 448.8 gallons per minute.
Decree
A final court decision regarding a water rights case. Once a decree has finalized a water right, the right is administered by the Colorado’s Division of Water Resources.
Designated Groundwater
Water not used to recharge or supplement continuously flowing surface streams under natural conditions. In 1965, the Legislature authorized the Colorado Ground Water Commission to create designated groundwater basins. These are areas where groundwater has historically been the predominant water supply, primarily along the Front Range and eastern Colorado. There are currently 8 designated basins located on Colorado’s eastern plains: Kiowa Bijou, Southern High Plains, Upper Black Squirrel Creek, Lost Creek, Camp Creek, Upper Big Sandy, Upper Crow Creek, and the Northern High Plains.
Developed (imported) Water
Water brought into a stream system from another unconnected source, for example, transmountain surface water or nontributary well water. This type of water can be reused to extinction, or used in augmentation or exchange plans.
Direct Flow (Direct Right)
Water diverted from a river or stream for use without interruption between diversion and use except for incidental purposes, such as settling or filtration.
Diversion
Removing water from its natural course or location by means of a water structure such as a ditch, pipeline, flume, reservoir, bypass, well or other device.
Drought
A long period of below-average precipitation.
Due Diligence
The actions made to complete a conditional water appropriation that demonstrate good faith effort toward putting a water right to beneficial use within a reasonable time period.
Dry up
Dry up is the change of the decreed irrigation water right from the land to another type of decreed water right. In order to do this, one must go through water court.
Exchange
A process by which water, under certain conditions, may be diverted out of priority at one point by replacing it with an equal quantity of water at another point.
Firm Annual Yield
The yearly quantity of water that can be dependably supplied from the raw water sources of a given water supply system.
The Fryingpan-Arkansas Project
A trans-mountain diversion which supplies southeastern Colorado with improved supplemental water supply for irrigation, municipal and industrial uses, hydroelectric power generation, and recreational opportunities.
Futile Call
A situation in which a junior (more recent) priority is allowed to continue to divert water in spite of a downstream senior call because curtailing the junior right would not reasonable.
Groundwater
Water beneath the earth's surface, often between saturated soil and rock, that supplies wells and springs.
Groundwater Use Rights
Per the 1965 Ground Water Management Act, every new well in the state of Colorado that diverts tributary, nontributary, Denver Basin groundwater, or geothermal resources must have a well permit through the Colorado Division of Water Resources.
Evapotranspiration (ET)
The process by which water is transmitted as a vapor to the atmosphere as the result of evaporation from any surface and transpiration from plants.
Exchange Decree
A water court decree that allows an upstream diverter to take the water that would usually flow to a downstream diverter. The upstream diverter must provide the downstream diverter with a suitable replacement supply of water, in amount, timing, and quality, from some other source.
Exempt Well
Wells that are exempt from water rights administration under the priority system. Permits for exempt wells typically limit the pumping rate to no more than 15 gallons per minute. Examples of exempt wells include: household use only, domestic and livestock wells, pre-1972 unregistered wells, commercial exempt wells, monitoring and observation wells, and replacement wells. Until 1971, wells providing groundwater for domestic use were not regulated. Now, although still exempt from the priority system, they do require a permit from the State Engineer’s Office.
Historical Consumptive Use (HCU)
When a water right owner wishes to change a water right, the amount of water that can be changed is limited to the historical consumptive use of the water right. The HCU is the amount of water that has been put to beneficial use (see consumptive use definition), and thus, the amount of water that may properly be subject to a change.
Hydropower
The use of water in the generation of electricity at plants where the turbine generators are driven by moving water. Hydroelectric water use is most commonly an instream use.
Injury
The action of another that causes or may cause the holders of decreed water rights to suffer loss of water in the time, place and amount they are entitled to use that water.
Instream Flow Water Right
Water flowing in a natural stream bed; water required for maintaining stream flow or for fish.
Junior Water Right
Water rights that are more recently established than older or more senior rights. Junior rights may not have the right to divert if their diversion causes a senior user to lack the full beneficial use decreed to the senior water right.
Native Water
Water arising within a basin or drainage (eg. The Arkansas River Basin).
Non-Consumptive Use (NCU)
Water diverted for use that is not consumed or permanently removed from the river system. For example, water withdrawn for purposes such as hydropower generation is returned to the river. It also includes uses such as boating or fishing where the water is still available for other uses at the same site.
Non-exempt Wells
Non-exempt wells are governed by the priority system, and may be curtailed. These wells include any other type of well not noted in the definition of exempt wells. In over-appropriated areas of the state like the Arkansas River, new non-exempt wells are required to replace out-of-priority diversions by means of an augmentation plan. For more information, please contact UAWCD.
Nontributary Groundwater
Groundwater outside of the boundaries of any designated groundwater basin, the withdrawal of which will not, within one hundred years, deplete the flow of a natural stream at an annual rate greater than one-tenth of one percent of the annual rate of withdrawal.
Not Nontributary Groundwater
Denver Basin groundwater, the withdrawal of which will deplete the flow of a natural stream at an annual rate of greater than one-tenth of one percent of the annual rate of withdrawal.
Over-appropriation
A watershed or stream segment is considered over-appropriated if the water court has approved more water rights decrees on that stream than there is water actually available. Water availability is determined by physical and legal constraints.
Priority
The ranking of a water right in relation to all other water rights drawing on the same stream system. The right of an earlier (senior) appropriator to divert from a natural stream in preference to a later (junior) appropriator.
Priority date
Priority date is determined by the year in which the application for the water right was filed.
Prior Appropriation
The water law doctrine that confers priority to use water from natural streams based upon when the water rights were acquired. Also referred to as the priority doctrine. This is the historical basis for Colorado water law and is sometimes known as the Colorado Doctrine or the principle of “first in time, first in right.”
Project Water
Water from the transmountain diversion from the Frying Pan River to the Arkansas River Basin, officially called the Frying Pan Arkansas Project.
Recreational In-channel Division Right (RICD):
A water right held by a local governmental entity for structures that control the flow of water for rafting and kayaking.
Reservoir
An impoundment of collected water controlled by a dam or storage tank.
Return Flow
Water that returns to streams and rivers after it has been applied to beneficial use. It may return as a surface flow, or as in in-flow of tributary groundwater.
Riparian
Referring to land or habitat immediately adjacent to the stream channel.
River Call
In Colorado, after the streams peak from spring snowmelt, the reservoirs have filled as much as they can based upon their allotment in the priority system, and stream flows start to drop, some water rights in the river system may not have sufficient water to fulfill their court-decreed diversion amount. Water users may then start to call for their water based on the priority system of “first in time, first in right.” The priority date of the river call may change each day depending on the stream flow available, and the seniority of the diversions that need water on that day. The Colorado Division of Water Resources keeps track of all calls for water on its Web site www.water.state.co.us.
Senior Water Right
Water rights that are decreed earliest in priority by the water court.
State Engineers Office (SEO)
See Colorado Division of Water Resources.
Storage Right
A right to impound water in priority for later use, expressed in number of acre-feet of water that the reservoir or storage vessel can hold.
Stream Depletion
Losses of water to a stream or river caused by well use, evaporation or otherwise.
Substitute Water Supply Plans
Allow for out-of-priority diversions if sufficient replacement water can be provided to senior rights to cover depletions. SWSP’s are approved by the State Engineer for defined periods of time. In contract, augmentation plans, which are long-term, must be approved by water court.
Surface Water
Water that flows in streams, rivers, natural lakes, wetlands and reservoirs.
Transmissivity
A measure of the ability of an aquifer to transmit water.
Trans-basin Diversion
The conveyance of water from its natural drainage basin into another basin for beneficial use.
Trans-mountain Diversion
The conveyance of water from one drainage basin to another across the Continental Divide.
Trans-mountain Water
Water whose source is from an adjacent basin (eg. Western Slope water).
Tributary
A stream or river that flows into a larger one.
Tributary Groundwater
All subsurface water hydraulically connected to a surface stream, the pumping of which would have a measurable effect on the surface stream within one hundred years.
Upper Arkansas Voluntary Flow Management Program
For more info click here.
Water Commissioner
Employee of the Colorado Division of Water Resources responsible for ensuring that the priority system is followed, enforcing the decrees and water laws of the State of Colorado.
Water Conservancy District
Established by decree of a court under the Water Conservancy District Act of 1937. Among other powers, a conservancy district can obtain rights-of-way for works; contract with the United States or otherwise provide for construction of facilities; assume contractual or bonded indebtedness; administer, operate, and maintain physical works; have authority to conserve, control, allocate, and distribute water supplies; and have contracting and limited taxing authority to derive the revenues necessary to accomplish its purposes. There are currently 51 water conservancy districts in Colorado.
Water Conservation
The saving and reservation of water from reduced use by placing the saved/conserved water into storage so that it can be available for later use.
Water Conservation District
A water conservation district is a local policy-making body that the General Assembly created directly by statute to protect and develop the waters to which Colorado is entitled. Each conservation district covers a large geographical area and has a number of conservancy districts within it. Conservation districts also have the power to issue bonds and levy taxes and user fees. There are currently three conservation districts in Colorado: Colorado River Water Conservation District, Rio Grande Water Conservation District, and Southwestern Water Conservation District.
Water Court
Starting with an 1879 statute, the Colorado General Assembly assigned the duty of setting water right priority dates and amounts to the courts. This differs from almost all other western states, which use a permit system. In Colorado, water courts have jurisdiction over all water right decree applications for surface water, tributary groundwater, nontributary, Denver Basin groundwater outside of designated groundwater basins, and geothermal resources. In addition, they review cases of reasonable diligence for conditional water rights, changes of water rights, exchanges, and augmentation plans, and appeals from State or Division Engineer enforcement orders.
Water Division
There are seven water divisions in Colorado and the UAWCD District boundaries are located within Division 2.
Water Judge
Water judges are district court judges who have the authority to confirm water rights and determine all other water matters within their water division.
Watershed
The region draining into a river, river system or other body of water.
Water Right
A property right to the use of a portion of the public’s surface or tributary groundwater resource obtained under applicable legal procedures.
Well Permit
A permit to drill a well issued by the Colorado Division of Water Resources.
Prior appropriation water rights are presumed to have been abandoned if they are not exercised during a 10-year period. The State Engineer compiles a periodic ranking list of active decreed water right priorities and an abandonment list.
Absolute Water Right
A property right to put water to a specific beneficial use, in a specified portion, in accordance with its priority.
Acre-foot (a/f)
A measurement of water. It is the amount of water that will cover an acre of land at a depth of one foot. Think the size of almost a football field!
It is equivalent to 325,851 gallons. An acre-foot typically serves the needs for a family of four for a year.
Adjudication
Judicial proceedings before the State of Colorado Water Court to hear and decide a water rights case.
Alluvial Storage
Below ground water storage. See Trout Creek Park project.
Appropriate
To take the legal actions necessary to create a right to divert water from a stream, tributary or aquifer for application to beneficial use.
Appropriation
The right to take water from a stream or aquifer for beneficial use, at a specific rate or flow. Water courts must issue a decree for the appropriated water.
Aquifer
A water-bearing layer of rock or sediment capable of yielding supplies of water.
Arkansas River Compact of 1948
This compact apportions the waters of the Arkansas River between Colorado and Kansas based on the inflow to John Martin Reservoir during the winter storage season (December 1 to March 31). This water in storage can be released at the demand of either state after April 1.
Augmentation
Supplementing the water supply of a stream affected by well depletion, in order to protect senior water rights on a stream. Augmentation doesn’t put water in the well and is not designed to recharge the aquifer. Click here for more info.
Augmentation Certificate
A document representing the ownership of an augmentation water right.
Augmentation Plan
An augmentation plan is a court-approved plan, which is designed to protect existing senior water rights by replacing water used in a new project. The UAWCD has a blanket augmentation plan and administers replacement water programs for thousands of customers using infrastructure located in the upper reaches of the Arkansas River Valley above Pueblo, and various legal instruments and decrees. Click here for more info.
Basin
A region drained by a single river system. The UAWCD is located in the Upper Arkansas River Basin. There are eight major river basins in Colorado, including the Denver Metro area basin.
Beneficial Use
The basis, measure and limit of a water right. The lawful appropriation that uses reasonably efficient practices to put water to use without waste.
Blue Line
Defines the geographic area of the District's blanket augmentation plan.
Call
The right of a senior water rights holder to “call” for his/her water. Junior water rights holders must pass the water on to the senior holder and not divert until the right is satisfied. Administered by the Division of Water Resources.
Change of Water Right Decree
A water court decree that allows a different type of use, different point of diversion, or different place of use, while retaining the senior priority of the original water right. For example, changing an irrigation decreed water right to a municipal decreed water right. A change of use must be applied for and approved through water court. A change of water right is not required for a simply a change in ownership. Only the historical consumptive use of the water right might be change to a new use, not the historical diversion in order to ensure that no other water rights holders will be injured by the new change of water right.
Colorado Division of Water Resources (DWR)
Also known as the Office of the State Engineer. For over 125 years, the DWR has been empowered to administer all water rights according to the Appropriation Doctrine (in short, 1st in time, 1st in right). Most of this work is done by Division Offices located in the seven major river basins of the state. These offices employ water commissioners to ensure the priority system is followed, enforcing the decrees and water laws of the State of Colorado. The Colorado Ground Water Law of 1957 established the permitting requirement of ground water wells, and by 1969, surface and ground water rights were administered together.
Colorado Groundwater Commission (CGWC)
The regulatory and permitting agency authorized by the General Assembly to manage and control ground water resources within eight Designated Ground Water Basins in eastern Colorado.
Colorado Water Conservation Board (CWCB)
The state agency vested with the exclusive authority to appropriate waters of natural streams and lakes as determined may be required for minimum stream flows and volumes for natural lakes, in amounts that are determined to be necessary to preserve the natural environment to a reasonable degree.
Compact
A contract between states that is ratified by those states legislatures and by the U.S. Congress. The contract controls the division of water in a river system that flows across state boundaries.
Conditional Water Right Decree
A conditional decree holds a date in the priority system which is then finalized when the water is put to beneficial use. Because water projects are often complex and take a long time to complete, this is a helpful tool.
Consumptive Use
Water that is withdrawn through evaporation and transpiration, incorporated into products or crops, consumed by humans or livestock, or otherwise removed from the immediate water environment.
Cubic Feet Per Second (CFS)
A rate of flow for water in a moving stream or diversion. Water flowing at 1 cfs will deliver 448.8 gallons per minute.
Decree
A final court decision regarding a water rights case. Once a decree has finalized a water right, the right is administered by the Colorado’s Division of Water Resources.
Designated Groundwater
Water not used to recharge or supplement continuously flowing surface streams under natural conditions. In 1965, the Legislature authorized the Colorado Ground Water Commission to create designated groundwater basins. These are areas where groundwater has historically been the predominant water supply, primarily along the Front Range and eastern Colorado. There are currently 8 designated basins located on Colorado’s eastern plains: Kiowa Bijou, Southern High Plains, Upper Black Squirrel Creek, Lost Creek, Camp Creek, Upper Big Sandy, Upper Crow Creek, and the Northern High Plains.
Developed (imported) Water
Water brought into a stream system from another unconnected source, for example, transmountain surface water or nontributary well water. This type of water can be reused to extinction, or used in augmentation or exchange plans.
Direct Flow (Direct Right)
Water diverted from a river or stream for use without interruption between diversion and use except for incidental purposes, such as settling or filtration.
Diversion
Removing water from its natural course or location by means of a water structure such as a ditch, pipeline, flume, reservoir, bypass, well or other device.
Drought
A long period of below-average precipitation.
Due Diligence
The actions made to complete a conditional water appropriation that demonstrate good faith effort toward putting a water right to beneficial use within a reasonable time period.
Dry up
Dry up is the change of the decreed irrigation water right from the land to another type of decreed water right. In order to do this, one must go through water court.
Exchange
A process by which water, under certain conditions, may be diverted out of priority at one point by replacing it with an equal quantity of water at another point.
Firm Annual Yield
The yearly quantity of water that can be dependably supplied from the raw water sources of a given water supply system.
The Fryingpan-Arkansas Project
A trans-mountain diversion which supplies southeastern Colorado with improved supplemental water supply for irrigation, municipal and industrial uses, hydroelectric power generation, and recreational opportunities.
Futile Call
A situation in which a junior (more recent) priority is allowed to continue to divert water in spite of a downstream senior call because curtailing the junior right would not reasonable.
Groundwater
Water beneath the earth's surface, often between saturated soil and rock, that supplies wells and springs.
Groundwater Use Rights
Per the 1965 Ground Water Management Act, every new well in the state of Colorado that diverts tributary, nontributary, Denver Basin groundwater, or geothermal resources must have a well permit through the Colorado Division of Water Resources.
Evapotranspiration (ET)
The process by which water is transmitted as a vapor to the atmosphere as the result of evaporation from any surface and transpiration from plants.
Exchange Decree
A water court decree that allows an upstream diverter to take the water that would usually flow to a downstream diverter. The upstream diverter must provide the downstream diverter with a suitable replacement supply of water, in amount, timing, and quality, from some other source.
Exempt Well
Wells that are exempt from water rights administration under the priority system. Permits for exempt wells typically limit the pumping rate to no more than 15 gallons per minute. Examples of exempt wells include: household use only, domestic and livestock wells, pre-1972 unregistered wells, commercial exempt wells, monitoring and observation wells, and replacement wells. Until 1971, wells providing groundwater for domestic use were not regulated. Now, although still exempt from the priority system, they do require a permit from the State Engineer’s Office.
Historical Consumptive Use (HCU)
When a water right owner wishes to change a water right, the amount of water that can be changed is limited to the historical consumptive use of the water right. The HCU is the amount of water that has been put to beneficial use (see consumptive use definition), and thus, the amount of water that may properly be subject to a change.
Hydropower
The use of water in the generation of electricity at plants where the turbine generators are driven by moving water. Hydroelectric water use is most commonly an instream use.
Injury
The action of another that causes or may cause the holders of decreed water rights to suffer loss of water in the time, place and amount they are entitled to use that water.
Instream Flow Water Right
Water flowing in a natural stream bed; water required for maintaining stream flow or for fish.
Junior Water Right
Water rights that are more recently established than older or more senior rights. Junior rights may not have the right to divert if their diversion causes a senior user to lack the full beneficial use decreed to the senior water right.
Native Water
Water arising within a basin or drainage (eg. The Arkansas River Basin).
Non-Consumptive Use (NCU)
Water diverted for use that is not consumed or permanently removed from the river system. For example, water withdrawn for purposes such as hydropower generation is returned to the river. It also includes uses such as boating or fishing where the water is still available for other uses at the same site.
Non-exempt Wells
Non-exempt wells are governed by the priority system, and may be curtailed. These wells include any other type of well not noted in the definition of exempt wells. In over-appropriated areas of the state like the Arkansas River, new non-exempt wells are required to replace out-of-priority diversions by means of an augmentation plan. For more information, please contact UAWCD.
Nontributary Groundwater
Groundwater outside of the boundaries of any designated groundwater basin, the withdrawal of which will not, within one hundred years, deplete the flow of a natural stream at an annual rate greater than one-tenth of one percent of the annual rate of withdrawal.
Not Nontributary Groundwater
Denver Basin groundwater, the withdrawal of which will deplete the flow of a natural stream at an annual rate of greater than one-tenth of one percent of the annual rate of withdrawal.
Over-appropriation
A watershed or stream segment is considered over-appropriated if the water court has approved more water rights decrees on that stream than there is water actually available. Water availability is determined by physical and legal constraints.
Priority
The ranking of a water right in relation to all other water rights drawing on the same stream system. The right of an earlier (senior) appropriator to divert from a natural stream in preference to a later (junior) appropriator.
Priority date
Priority date is determined by the year in which the application for the water right was filed.
Prior Appropriation
The water law doctrine that confers priority to use water from natural streams based upon when the water rights were acquired. Also referred to as the priority doctrine. This is the historical basis for Colorado water law and is sometimes known as the Colorado Doctrine or the principle of “first in time, first in right.”
Project Water
Water from the transmountain diversion from the Frying Pan River to the Arkansas River Basin, officially called the Frying Pan Arkansas Project.
Recreational In-channel Division Right (RICD):
A water right held by a local governmental entity for structures that control the flow of water for rafting and kayaking.
Reservoir
An impoundment of collected water controlled by a dam or storage tank.
Return Flow
Water that returns to streams and rivers after it has been applied to beneficial use. It may return as a surface flow, or as in in-flow of tributary groundwater.
Riparian
Referring to land or habitat immediately adjacent to the stream channel.
River Call
In Colorado, after the streams peak from spring snowmelt, the reservoirs have filled as much as they can based upon their allotment in the priority system, and stream flows start to drop, some water rights in the river system may not have sufficient water to fulfill their court-decreed diversion amount. Water users may then start to call for their water based on the priority system of “first in time, first in right.” The priority date of the river call may change each day depending on the stream flow available, and the seniority of the diversions that need water on that day. The Colorado Division of Water Resources keeps track of all calls for water on its Web site www.water.state.co.us.
Senior Water Right
Water rights that are decreed earliest in priority by the water court.
State Engineers Office (SEO)
See Colorado Division of Water Resources.
Storage Right
A right to impound water in priority for later use, expressed in number of acre-feet of water that the reservoir or storage vessel can hold.
Stream Depletion
Losses of water to a stream or river caused by well use, evaporation or otherwise.
Substitute Water Supply Plans
Allow for out-of-priority diversions if sufficient replacement water can be provided to senior rights to cover depletions. SWSP’s are approved by the State Engineer for defined periods of time. In contract, augmentation plans, which are long-term, must be approved by water court.
Surface Water
Water that flows in streams, rivers, natural lakes, wetlands and reservoirs.
Transmissivity
A measure of the ability of an aquifer to transmit water.
Trans-basin Diversion
The conveyance of water from its natural drainage basin into another basin for beneficial use.
Trans-mountain Diversion
The conveyance of water from one drainage basin to another across the Continental Divide.
Trans-mountain Water
Water whose source is from an adjacent basin (eg. Western Slope water).
Tributary
A stream or river that flows into a larger one.
Tributary Groundwater
All subsurface water hydraulically connected to a surface stream, the pumping of which would have a measurable effect on the surface stream within one hundred years.
Upper Arkansas Voluntary Flow Management Program
For more info click here.
Water Commissioner
Employee of the Colorado Division of Water Resources responsible for ensuring that the priority system is followed, enforcing the decrees and water laws of the State of Colorado.
Water Conservancy District
Established by decree of a court under the Water Conservancy District Act of 1937. Among other powers, a conservancy district can obtain rights-of-way for works; contract with the United States or otherwise provide for construction of facilities; assume contractual or bonded indebtedness; administer, operate, and maintain physical works; have authority to conserve, control, allocate, and distribute water supplies; and have contracting and limited taxing authority to derive the revenues necessary to accomplish its purposes. There are currently 51 water conservancy districts in Colorado.
Water Conservation
The saving and reservation of water from reduced use by placing the saved/conserved water into storage so that it can be available for later use.
Water Conservation District
A water conservation district is a local policy-making body that the General Assembly created directly by statute to protect and develop the waters to which Colorado is entitled. Each conservation district covers a large geographical area and has a number of conservancy districts within it. Conservation districts also have the power to issue bonds and levy taxes and user fees. There are currently three conservation districts in Colorado: Colorado River Water Conservation District, Rio Grande Water Conservation District, and Southwestern Water Conservation District.
Water Court
Starting with an 1879 statute, the Colorado General Assembly assigned the duty of setting water right priority dates and amounts to the courts. This differs from almost all other western states, which use a permit system. In Colorado, water courts have jurisdiction over all water right decree applications for surface water, tributary groundwater, nontributary, Denver Basin groundwater outside of designated groundwater basins, and geothermal resources. In addition, they review cases of reasonable diligence for conditional water rights, changes of water rights, exchanges, and augmentation plans, and appeals from State or Division Engineer enforcement orders.
Water Division
There are seven water divisions in Colorado and the UAWCD District boundaries are located within Division 2.
Water Judge
Water judges are district court judges who have the authority to confirm water rights and determine all other water matters within their water division.
Watershed
The region draining into a river, river system or other body of water.
Water Right
A property right to the use of a portion of the public’s surface or tributary groundwater resource obtained under applicable legal procedures.
Well Permit
A permit to drill a well issued by the Colorado Division of Water Resources.