Snake/Salt River Basin Plan
Summary of Wyoming Water Law
PREPARED BY: Gordon W.
“Jeff” Fassett, P.E.
May 3, 2002
Introduction and Background:
One of the primary tenets established in the Wyoming Water Development
Commission water planning process is that Wyoming water law would be respected
in all aspects throughout the process. Wyoming water law is the foundation
upon which all water use, development and protection is based; it provides
the predictable basis upon which existing use and future planning and investment
in the State’s most valuable and renewable resource are made. The vast information
base and the analyses of water use, availability and demands presented in
this river basin plan are guided and reviewed in accordance with the principles
of Wyoming law and administration of water rights. The water rights system
in Wyoming is administered by the State Engineer’s Office and State Board
of Control, both constitutionally-based administrative and quasi-judicial
entities of state government.
Wyoming’s water laws have evolved from the early establishment of legal
principles that were later embodied in our state’s Constitution and a series
of statutory laws written and adopted early in Wyoming’s history that have
stood the strong test of time and certainty. One early water dispute that
involved two territorial pioneers, William McCrea and Charles Moyer, is instructive
regarding the history of water law in Wyoming. Moyer, whose name is associated
with a now-famous spring in the coal-mining region north of Gillette, developed
that spring for irrigation in 1890. Previously, Mr. McCrea developed an
irrigation project along the Little Powder River downstream of, and partially
supplied by, Moyer’s spring. With Moyer’s development, McCrea’s ditch was
now short of water and the resulting argument was eventually elevated to
the Wyoming Supreme Court. In one of the first Court rulings on water matters,
the Court affirmed the “first in time, first in right” doctrine by siding
with McCrea. Through this 1896 ruling, the Supreme Court recognized the
concepts of the prior appropriation doctrine that Territorial Engineer Elwood
Mead had been advocating throughout his early tenure in the days leading
to statehood and the constitutional conventions.
As Engineer for the Territory of Wyoming, and later its first State
Engineer, Mead understood that water, in an arid region, must be administered
in a predictable and equitable fashion, and the methods he was fostering
were to allow the earlier developer of water to establish the senior right
for its continued use. The Wyoming State Constitution, in Article VIII,
adopted this priority system of appropriation and established the position
of State Engineer. Through the efforts of Mead, the Constitution also embodied
the basis of appropriating water on the concept of “beneficial use” to avoid
the potential for greatly exaggerated amounts of water being tied up needlessly
by early settlers and developers of water diversion systems. Mead was also
at the forefront of affirming a strong and active state role, as an independent,
responsive and unbiased decision-maker, in all aspects of appropriating and
administrating the waters of the state.
In this light, Mead was also the architect of the process for resolving
of water disputes. Rather than use a water court system as in the neighboring
state of Colorado, Wyoming established the State Board of Control within
its Constitution. In addition to its independent authority to review matters
initially decided by the State Engineer, the Board of Control is the adjudicator
of all water rights and the decision-maker of all requests for changes to
water rights. The Constitution declares all water in the state to be the
property of the state, subject to appropriation for beneficial use through
the administrative permitting of water rights. Water rights are considered
property rights that attach to the land or place of use. Yet, the law provides
that the owner of these rights may change the location of use, or the type
of use, by seeking approval of a change or modification to the water right
from the Board of Control. The final decisions of the Board of Control are
subject to judicial review. The Board of Control is made up of the State
Engineer and the four Water Division Superintendents.
Within this constitutional framework, the detailed statutory authority,
procedures, and administration were further defined by legislation and periodic
Court decisions. The State Engineer’s role is defined in Title 9, Chapter
1, Article 9, along with the general authority to establish fees for certain
services and some other minor activities of the agency. The majority of
Wyoming’s water laws are now codified primarily in Title 41 of Wyoming Statutes,
Under this Title, there are fourteen chapters that now include
the authority and activities of the Water Development Commission and the
laws associated with irrigation, drainage, watershed improvement, and water
and sewer districts. Several chapters also address interstate compacts,
described elsewhere in this basin plan, and the use of watercraft. Chapters
3 and 4 contain the important laws relating to the appropriation, administration
and adjudication of water rights in Wyoming. These statutes provide the
detailed authorities and procedures for the State Engineer and Board of Control
as they relate to their respective responsibilities for the general supervision
of the waters of the state, whether they be from surface streams, springs,
natural lakes or underground waters.
The key elements of Wyoming’s water laws were established
in the Constitution and the early statutory laws before and near the turn
of the century. From time to time, the legislature has judicially and periodically
modified this longstanding body of law to address emerging new issues of
the water users in the state. The laws addressing reservoirs were passed
in the early 1900’s; laws specific to groundwater sources were introduced
in the 1940’s and 1950’s, with the last significant change adopted in 1969.
Recently, laws addressing instream flow water rights were codified in 1986.
The basic framework of water right permitting actions and administration
has remained the same, all the while allowing for flexibility in answering
the needs of water users and subject to selective statutory changes that
address emerging concerns regarding the beneficial use of water. That is
why this set of laws is a part of the principles upon which the Snake/Salt
River Basin Plan is based.
Upon reflection of this brief introductory background, the
reader is invited to refer to our state constitution and state statutes for
a complete reading of the water law language referenced herein. In addition,
the reader is encouraged to review the detailed monogram entitled “Wyoming
Water Law: A Summary” by James J. Jacobs, Gordon W. Fassett and Donald J.
Brosz, published by the University of Wyoming, College of Agriculture, Cooperative
Extension Service and attached hereto as Appendix A. A comprehensive glossary
of water-related terms is also attached for reference as Appendix B.
Wyoming Water Law: A Summary
Wyoming Water Law: A Summary
James J. Jacobs, UW Professor, Natural Resource Specialist
Gordon Fassett, State Engineer, Cheyenne
Donald J. Brosz, Associate Director, Wyoming Water Research Center
Wyoming water law dates back to territorial days and is based on the
"doctrine of prior appropriation." Under this doctrine the first to put the
water to beneficial use has the first right, or "first in time is first in
right." Therefore, water rights in Wyoming, and in most of the western states,
are regulated by priority. This means the earliest rights are entitled to
water during periods of limited supply, while those with later rights are
denied water during these times.
The Wyoming Constitution provides that water of all natural streams,
springs, lakes, or other collections of still water be the property of the
The state engineer is the chief administrator of Wyoming waters. In
administering these waters, the state is divided into four water divisions.
Water division 1 includes the North Platte and South Platte River drainages
and the Little Snake and the Niobrara River drainages. Water division 2 includes
all drainages north of the Niobrara and North Platte River drainages and
east of the Big Horn Mountains. Water division 3 includes the Big Horn and
Clark's Fork River drainages, and water division 4 includes the Green, Bear,
and Snake River drainages. A Wyoming map showing the water divisions is found
A water division superintendent administers the waters of each water
division with assistance from water commissioners and hydrographer-commissioners.
These four superintendents and the state engineer constitute the state board
of control. The board meets quarterly to adjudicate or finalize water rights
and to consider other matters pertaining to water rights, such as change
in point of diversion and other amendments or corrections of water rights.
When you write the state engineer for necessary forms and information,
address correspondence to:
State Engineer's Office
4th Floor East
Cheyenne, Wyoming 82002
You can also obtain information from each of the water division superintendents'
offices, which are located in these Wyoming cities:
Water division 1: Torrington
Water division 2: Sheridan
Water division 3: Riverton
Water division 4: Cokeville
Prior to statehood in 1890, a water right could be established by a procedure
predicated on the use of water and the filing of a claim with territorial
officials. Water rights with priority dates before 1890 are termed "territorial"
water rights. Since statehood, the only way a water right can be acquired
in Wyoming is by securing a permit from the state engineer. Water rights
cannot be obtained by historic use or adverse possession in any case. Wyoming
water law requires that you follow certain procedures to obtain a valid water
right. Following is a summary of these procedures for surface and ground
Wyoming's first surface water laws were enacted in 1875. More comprehensive
laws were adopted along with the state constitution in 1890. In brief, and
paraphrased, these laws state:
- If you (or an association or corporation) want to use surface water,
you must first apply to the state engineer for a permit. Application forms
are available from the state engineer's office.
- An engineer or surveyor, licensed to practice in Wyoming, must make
a survey and prepare the maps and plans needed to apply for your permit.
Generally this engineer or land surveyor also has the necessary application
- Submit the application form, maps, and plans, along with a filing
fee, to the state engineer as a package. The priority date is established
by the date of application acceptance in the state engineer's office.
- Upon approval of the application, the state engineer issues a permit
for developing the proposed water project.
- You must complete and beneficially use the project within the time
specified on the approved permit.
- You must notify the state engineer on appropriate forms of the dates
construction began, when construction was completed, and when water was put
to beneficial use. The appropriate forms are provided with the approved permit.
- If in the time prescribed you cannot begin and complete the project
and put the water to use, the state engineer may be requested to extend any
or all of the time limits. Make your request before the original time limits
expire, and cite good cause for needing an extension. If a time extension
is granted, the date of priority remains the same.
- After the water has been put to beneficial use, or a reservoir constructed
and the notices as outlined in point 6 submitted, you must submit a final
proof of appropriation or construction to the appropriate water division
superintendent, who then submits it to the board of control. This proof is
advertised in a local newspaper, and an inspection of the project is made.
Only lands found to be irrigated and/or possessing a reservoir will be accepted
for adjudication. If everything is found in order and no protests are filed,
a certificate of appropriation and/or construction is issued by the board
of control and recorded in the county clerk's office in which the project
is located, as well as in the state engineer's office. It is then listed
in the tabulation of adjudicated rights for the respective division. This
is evidence of an adjudicated water right. Once adjudicated, the water right
is permanently attached to the specific land or place of use described on
the certificate of appropriation and cannot be removed except by action of
the state board of control to change the use or place of use (see page 7).
The adjudicated water right takes its place in the list of priorities for
that stream. Water is delivered to that right only when sufficient water
is available to meet all earlier water rights on that stream.
- Limits on unstored water for irrigation:
a. Water rights for irrigation are adjudicated on the
basis of one cubic foot per second (cfs) per 70 acres.
b. Water rights with priority dates of March 1, 1945, or earlier
are entitled to an additional 1 cfs per 70 acres. If you hold such a water
right, you are entitled to divert water in the volume of 2 cfs for each 70
acres of land before any water is made available to the holder of a water
right with a priority date after March 1, 1945.
If there is not sufficient water to furnish 2 cfs to each pre-March
1, 1945, water right, but more than enough to furnish 1 cfs to each of such
rights, then the surplus water is divided among those rights on a pro rata
basis. If there is so little water that each pre-March 1, 1945, right cannot
receive 1 cfs, they are regulated on a strict priority basis.
Any water beyond that required to furnish 2 cfs for each 70 acres
of pre-March 1, 1945, water rights is first allocated to rights with priority
dates after March 1, 1945, and before March 1, 1985. Wyoming's Excess Water
Law states that each water right with a priority date of post-March 1, 1945,
but pre-March 1, 1985, is entitled to 2 cfs per 70 acres before any water
is made available to post-March 1, 1985, water rights. If there is not sufficient
water to furnish 2 cfs to each post-March 1, 1945, and pre-March 1, 1985,
water right, but more than enough to furnish 1 cfs to each of these rights,
the excess water is divided among those rights on a pro rata basis. If there
is so little water that each post-March 1, 1945, and pre-March 1, 1985, water
right cannot receive 1 cfs, the rights are regulated on a strict priority
For post-March 1, 1985, water rights, those rights are entitled to
1 cfs per 70 acres only after all pre-March 1, 1985, rights have received
2 cfs per 70 acres. Under Excess Water Law, the post-March 1, 1985, water
rights may also receive 2 cfs if water is available.
- The granting of a water right by the state engineer does not include
the granting of ditch easements and rights of way. You must negotiate these
with the affected landowners.
The state engineer may issue you a permit for water storage and development
of a spring. File a simplified form, which does not require maps and plans
prepared by a registered engineer or surveyor, for the following water uses:
- Construction of small reservoirs for stock purposes only and fishing
reserve waters, where the capacity of such a reservoir does not exceed 20
acre-feet of water or the height of the dam does not exceed 20 feet.
- Construction of flood detention dams that:
a. Store 50 acre-feet of water or less
b. Have a dam height not exceeding 20 feet
c. Have as a minimum an outlet 18 inches in diameter, and
d. Have a dead storage that does not exceed 20 acre-feet.
- Development of springs may be filed on by one of two methods, depending
upon the rate of flow and the use to which the water will be applied. The
conditions that determine the method to use are described below:
a. If the spring flows 25 gallons per minute (gpm) or
less, and if the water is to be used only for stock watering and/or domestic
uses (which includes watering of lawns and gardens not exceeding 1 acre in
size), the spring shall be filed as ground water. No map is required. After
the approval of the application, some type of artificial diversion must be
constructed to qualify for a water right. The proposed method of development
of the spring and means of conveying the water to the point of use must be
described on the application under the section titled "Remarks."
b. If the spring flows in excess of 25 gpm (0.056 cfs) or
if the water will be used to irrigate more than 1 acre or if the water will
be used for any purpose other than stock watering or domestic use, a surface
water application form must be submitted using surface water procedures.
Preparation of this application, and the map that must accompany it, requires
the services of a professional engineer or land surveyor licensed to practice
in Wyoming. The engineer or land surveyor will handle the preparation of
these applications and the accompanying maps as well as their submission
to the state engineer.
A reservoir is entitled to be filled in priority once each year if water
is available. If water remains unused in the reservoir at the end of the
normal use period, the water is designated as carry-over storage and counts
toward providing water to meet the following year's supply for appropriation.
The 1986 Legislature declared that instream flow for maintenance or
improvement of existing stream fisheries is a beneficial use of water than
can be provided from natural streamflows or from storage water. A statutory
procedure was established for the state, represented by the Wyoming Water
Development Commission, to appropriate specified flow rates for instream
flows in segments of streams identified by studies and reports of the Wyoming
Game and Fish Commission. The WWDC must conduct a hydrologic study to determine
whether the instream flow can be provided from the natural flow of the stream
or whether storage water from an existing or new reservoir will be needed
for part or all of the instream use. The WWDC report is supplied to the state
engineer for his consideration. If storage water is needed from a new reservoir
project, normal legislative project authorization procedures must be followed
After receiving reports from the Game and Fish Commission and WWDC, the
state engineer may conduct his own evaluation of the proposed appropriations
for instream use. Before granting or denying a permit for instream flow in
the specified stream segment, the state engineer must conduct a public hearing
and consider all available reports and information. If granted, an instream
flow permit can contain a condition for review of continuation of the permit
at a future time.
The instream flow appropriation goes into effect the date the state engineer
approves the permit. The water right cannot be adjudicated by the board of
control for three years thereafter. An instream water right has a date of
priority as of the date that the application was received and recorded by
the state engineer, and all senior priority water rights must be recognized
in administration of the stream.
The state engineer cannot issue an instream flow permit if it would result
in loss of a portion of Wyoming's consumptive share of water allocated by
interstate compact or U.S. Supreme Court decree, or if it would result in
more water leaving Wyoming than allocated for uses downstream of Wyoming.
Other persons can appropriate water for instream flow on a segment of
a stream within 1 mile of the Wyoming state line or within 1 mile upstream
from major reservoirs on the Big Horn, Green, and Snake rivers.
The first Wyoming ground-water laws were enacted in 1945 and amended
in 1947. A new ground-water law went into effect March 1, 1958, repealing
and replacing the 1945 and 1947 laws. Major amendments were made in 1969.
Priority of Wells
- For all wells drilled prior to April 1, 1947, the date of priority
is the date the well was completed if a claim for the well was filed before
March 1, 1958, as provided by the law.
- For wells drilled between April 1, 1947, and March 1, 1958, the date
the well was registered established its priority date.
- After March 1, 1958, the priority date is the date the application
for a permit to drill the well is accepted in the state engineer's office.
- An exception to the above is a well used solely for stock and/or domestic
purposes. These wells, until the enactment of the 1969 amendment to the ground-water
law, were exempt from filing and held a preferred right over wells used for
all other purposes.
- Under the 1969 amendment, all domestic and/or stock wells drilled
after May 24, 1969, and all wells drilled for other purposes, establish a
priority as of the date the application for permit to drill is received in
the state engineer's office.
- Under the 1969 amendment, all stock and/or domestic wells drilled
and used before May 24, 1969, and registered with the state engineer before
December 31, 1972, established a priority date as of the well's completion
and water use.
Domestic and Stock Water Uses
The law defines domestic use as household use, including the watering
of lawns and gardens for noncommercial family use, where the area to be irrigated
does not exceed 1 acre. The quantity of water to be pumped for family or
stock use shall not exceed 25 gpm. A well may supply water to more than one,
but not more than three, single-family dwellings and still be considered
a domestic use provided that:
- The yield does not exceed 25 gpm
- The total area of lawns and gardens to be watered does not exceed
- No charge, hidden or otherwise, is levied for the use of the water
- The water is not used in conjunction with a commercial endeavor.
Stock watering use is defined as the normal watering of livestock, including
any project whereby water will be piped to no more than four points of use
within 1 mile of the well. Large feedlot operations or any project whereby
the water will be piped to five or more points of use, or the points of use
are greater than 1 mile from the well, are considered miscellaneous use.
Ground Water Permitting Procedures
The same general procedures to acquire surface-water rights apply to
acquiring a ground-water right:
- Before a well is drilled, you must file an application and have it
approved by the state engineer. This requirement applies to all wells used
for any purpose.
- Forms to be filed with the state engineer are available from that
office, the water division superintendent's office, or the county clerk's
- A permit to construct a well will generally be granted as a matter
of course by the state engineer. An exception may be in a ground-water control
- The board of control may designate a control area where:
a. The use of ground water is approaching a use equal to the
current recharge rate
b. Ground-water levels are declining or have declined excessively
c. Conflicts between users are occurring or are foreseeable
d. The waste of water is occurring or may occur, or
e. Other conditions exist or may arise that require regulation
for protection of the public interest.
- You must begin construction of a well within a year after the permit
is granted; notify the state engineer's office by submitting a notice of
commencement. You must complete the well and apply the water to beneficial
use before the dates specified on the permit and submit the proper notice(s)
verifying compliance to the state engineer's office.
- If you cannot begin construction of a well, complete it, or put the
water to use in the time prescribed, request in writing (to the state engineer)
an extension of time. Be sure to state good cause in the request.
- A plat, showing the location of the well(s) and the point(s) of use
and distribution system, is required at the time of filing the final proof
of appropriation and beneficial use. Have this plat certified by an engineer
or land surveyor licensed to practice in Wyoming.
- After you have filed final proof of appropriation, an inspection of
the project is made by the division water superintendent, and the proof is
advertised. If everything is in order and no protests are filed, you are
issued a certificate of appropriation by the board of control. It is recorded
in the county clerk's office where the project is located and in the state
engineer's office as well. This is your evidence of an adjudicated water
Changes in Location and Depth
You may change a well location within the same aquifer in the vicinity
of the original location or the well depth without loss of priority, provided
you have obtained approval from the state board of control if the ground-water
right has been adjudicated or the groundwater right has not been adjudicated
but the water has been applied to beneficial use. In cases involving domestic
and stock water wells that are not adjudicated but whose water has been applied
to beneficial use, the state engineer may approve a change of location. If
the right is not adjudicated and the water has not been applied to beneficial
use, approval for the change in location may be granted by the state engineer.
For all wells, the state engineer may approve a change in well location even
if the water has not been put to a beneficial use.
Special Water Right Conditions for Ground Water
- Remember that the permit to appropriate ground water carries with
it no guarantee of a continued water level or artesian pressure.
- Where underground waters in different aquifers are so interconnected
as to constitute one source of supply, or underground water and surface water
are so interconnected as to constitute one source of supply, priorities of
rights to the use of the interconnected waters shall be correlated and a
single schedule of priorities shall relate to the common water supply.
- By-product water is water that has not been put to prior beneficial
use, and is a by-product of some non- water-related economic activity and
has been developed only as a result of such activity such as oil and gas
production, mining, etc.
Wyoming water law defines the preferred uses of both surface and ground
water and lists them in the following order:
- Drinking water for both humans and livestock<
- Water for municipal purposes
- Water for steam engines and general railway use; water for cooking,
laundering, bathing, and refrigerating (including the manufacturing of ice);
water for steam and hot-water heating plants, steam power plants
- Water for industrial purposes.
All uses of water other than those listed as preferred uses are considered
When the water supply is insufficient to meet water rights, rights with
a preferred use do not take precedence over a non-preferred use. The priority
date of a water right, preferred or non-preferred, determines who is entitled
to water. The only way you can obtain a preferred right for a non-preferred
prior right is by purchase or by condemnation through court action. The right
of condemnation cannot be used by industrial concerns to obtain water rights.
However, ground-water wells yielding 25 gpm or less and used solely for domestic
and stock purposes do have preferred rights over wells for all other uses
regardless of date of priority.
Example: An irrigation water right (non-preferred use) with an
early priority is entitled to use water even when it may involve denying
water to a municipality (preferred use) with a later right. The municipality
may acquire, through condemnation if necessary, the earlier irrigation right
and change it to municipal use, provided just compensation is paid.
Keeping Water Rights Valid
To keep a water right valid when changes are made in the point of diversion,
in the location of a well, in the location of an irrigation ditch, or similar
circumstances, you must secure permission. Do this by petitioning the state
board of control if the water is adjudicated. If it is not adjudicated, send
your petition to the state engineer.
In most instances, obtaining permission for changes does not change the
priority date of the water right but keeps the water right up to date and
legal. Public hearings on the changes may be held to ensure that no injury
occurs to the other water right holders because of the change. Keep the water
right in proper standing so no legal questions are raised concerning its
Change in Use
If you own a water right and wish to change it from its current use
to another use, or from the place of use under the existing right to a new
place of use, you must file a petition requesting permission for a change.
The petition sets forth all pertinent facts about the existing use and the
proposed change in use. When you request a change in place of use, all pertinent
information about the existing use and the proposed place of use shall be
specified in the petition. The board may require that an advertised public
hearing be held at your expense. The petitioner shall provide a transcript
of the public hearing to the board. The change in use, or change in place
of use, may be allowed.
If such an allowance is granted, the quantity of water transferred by
the granting of the petition shall not exceed the amount of water historically
diverted under the existing use. Furthermore, the historic rate of diversion
and the amount consumed cannot exceed that under the existing use. Finally,
such a petition, if allowed, shall not decrease the historic amount of return
flow, or in any manner injure other existing lawful appropriators. The board
of control considers all facts it believes pertinent to the transfer. These
may include the following:
- The economic loss to the community and the state if the use from which
the right is transferred is discontinued
- The extent to which such economic loss will be offset by the new use
- Whether other sources of water are available for the new use In all
cases where the matter of compensation is in dispute, the question of compensation
shall be submitted to the proper district court for determination.
Subdivisions with Attached Water Rights
Wyoming law now provides that any time you subdivide a parcel of land
with water rights attached, you (the developer) must dispose of the water
rights in one of three ways:
- Voluntarily abandon the water rights, removing them from the land forever
- Transfer the water rights to other owned lands that have no other
water right from the same source
- Develop a subdivision irrigation plan showing which lands have the
water right, amount of the water right, supply and waste ditches, and other
information necessary for the protection of individual lot owners in retaining
the water right on the land.
Each of these actions requires review by the state engineer's office
or the state board of control before the subdivision can be approved by the
Water Right Abandonment
A water right for surface or ground water not used for five successive
years when water is available to satisfy the right is considered abandoned,
but a statutory procedure must be followed to bring about legal abandonment.
The law provides a procedure for abandonment, but it must be brought by an
affected water user who has a priority equal or junior to the right being
abandoned, or by the state engineer. If a right is declared abandoned, the
user forfeits all water rights, easements, ditch rights, and the like, and
the water again becomes subject to appropriation. Water must have been available
but not used for an abandonment to take place. Wyoming law provides standing
so that abandonment action can be brought by a pre-March 1, 1945, water right
holder, even though senior in priority, against another pre-March 1, 1945,
water right holder to protect the right to surplus water.
Wyoming Water Law
- Beneficial use is the basis, measure, and limit to the right to use
water at all times.
- To bring about a more economical use of the available water supply,
two or more water users may rotate the use of their combined water rights
after obtaining permission of the water division superintendent or water
- You are responsible for maintenance of your ditches so that the water
therefrom does not flood or damage the property of others.
- You are responsible for your waste water at all times.
- In administering water to the various appropriations on a stream,
the state is obligated to deliver the full amount of any appropriation in
priority at its head gate out of the stream. Any ditch loss between the head
gate and the appropriator's land is the responsibility of the appropriator.
- Temporary uses of water, such as for oil well drilling, highway construction,
etc., may be granted by the state engineer upon proper application.
- In any case where a ditch was in place before any houses or other
property, the property owners are compelled to protect themselves from any
damage created by seepage from the ditch. If, because of seepage, a newly
built ditch creates damage to property that was present before the ditch
was built, the ditch owners shall be liable for any damage.
In Wyoming a valid right to the use of water may be acquired only by
following the procedures established by state law for both surface and ground
Water users should be sure of the status of their water rights. Check
the records in the county clerk's office, or through the state engineer's
office. The records indicate the appropriation amount, priority of the right,
and how and where the water is to be used. If there are any questions, check
with the state engineer's office and request complete information on the
status of the water right in question.
Glossary of Water Related Terms
GLOSSARY OF WATER-RELATED TERMS
Abandonment: The loss of a water right based on the nonuse of
that water right when water was available for a period of 5 consecutive years,
or the voluntary relinquishment of an adjudicated water right.
Acre-Foot (AF): The volume of water required to cover 1 acre of
land to a depth of 1 foot; 325,850 gallons or 1233.5 cubic meters. One acre-foot
supplies a family of four for about one year.
Additional Supply: Water from a groundwater source applied to
lands which already have a more senior original supply water right.
Adjudication: A judicial or quasi-judicial proceeding in which
a priority is assigned to an appropriation and a decree or certificate issued
publicly recognizing the defined water right and conveying property-right
status on the appropriation.
Administrative Procedures: Proceedings before an officer of the
executive branch of government as distinguished from proceedings before the
judicial branch of government.
Alluvium: Deposits of sand and gravel derived from erosional processes
and laid down in river channels and floodplains.
Appropriation: The acquisition of a water right by fulfilling
the requirements of law for a certain portion of the waters of the state
and the application of same to a beneficial use.
Aquifer: A water bearing geologic formation.
Artesian Well: A well that taps a confined aquifer and may have
a pressure sufficient to support a flowing well.
Artificial Recharge: The addition of water to the groundwater
reservoir by human activities, such as irrigation or induced infiltration
from streams, wells, or spreading basins.
Bank Storage: The water contained in an aquifer hydraulically
connected with a stream or lake and capable of supplying water to the stream
or lake following a lowering of the free water surface, or capable of storing
water flowing from the stream or lake on a rise of the free water surface.
Beneficial Use: The use of that amount of water that is reasonable
and appropriate under reasonable efficient practices to accomplish, without
waste, the purpose for which the diversion is lawfully made and without limiting
the generality of the foregoing, and can include impoundment of water for
recreational purposes, including fishery or wildlife.
Board of Control: A Constitutionally-created quasi-judicial executive
branch board made up of the State Engineer and Superintendents of the four
Wyoming water divisions whose purpose is to oversee and decide matters of
water right adjudication and changes. Its decisions are subject to review
by Wyoming courts on appeal.
Braided Channel: Situation where the water flow of a river or
creek is not confined to a single channel, but instead flows into multiple
channels of varying width and capacity.
Call: The placing of a call by any appropriator to the water commissioner
to regulate appropriations to their permitted priorities and amounts. In
such cases, junior priorities may be curtailed or called out so that a senior
is able to divert its full entitlement.
Canal: A constructed open channel for transporting water from
the source of supply to the point of distribution.
Capacity: The maximum volume of water that can be held in a
reservoir, or the flow rate that can be transported through a channel, ditch,
pipeline, weir, etc., without the facility overflowing or submerging.
Capillary fringe: Saturated layer at the top of the groundwater
zone consisting of water held by capillary tension above the level that would
represent the hydrostatic surface influenced by gravity alone.
Channel: A natural stream that conveys water; a ditch or canal
excavated for the conveyance of water.
Channel capacity: Maximum discharge that can be contained within
the banks of a channel.
Closed basin: Area of land that has no drainage outlet to an
Compact: A contract between states of the union, entered into
with the consent of the national government, and in water, defining the relative
rights of two or more states on an interstate stream to use the waters of
Cone of Depression: The resulting water table form representing
the gradient towards a well caused by withdrawals from the aquifer.
Confined Aquifer: An aquifer enclosed between impermeable formations.
Conjunctive Management: Treating ground water and surface water
as a single, connected source.
Consistent Units: A system that permits using only one unit of
a kind in scientific quantifications or calculations. Computational procedures
require units be consistent. Data expressed in units other than those of
a chosen system must be converted to the chosen system. Some conversion
factors used in computations are given below:
To Convert To Multiply by
Gallons per minute Cubic feet per second 0.002228
(permeability) Feet per second 1,5472 x 10-6
(transmissivity) Feet squared per second 1.5472 x 10-6
Acre-feet Cubic feet 43,560
Cubic feet per second Gallons per minute 448.8
One year (365 days) Seconds 31,536,000
One month (1/12
year) Seconds 2,628,000
One day Seconds 86,400
Consumptive Use: The amount of water consumed during use of the
water and no longer available to the stream system. For irrigation, consumptive
use is water used by crops in transpiration and building of plant tissue
and excludes return flow.
Continuous Record: Data (streamflow, diversion records) collected
on a consistent, long-term basis.
Conveyance Loss: The loss of water from a conduit due to leakage,
seepage, evaporation, or evapotranspiration.
Creek: A natural stream of water, normally smaller than, and often
tributary to, a river.
Critical Year: Usually considered a year in which the annual precipitation
was considerably less than average and runoff in most of the streams was
low. The critical year is used to test the dependability of water rights
under worst-case conditions.
Cross-Section: View of a channel taken perpendicular to the flow,
or view of a dam taken perpendicular to its length.
Cubic foot per second (cfs): Standard measure of discharge for
streamflow, indicating one cubic foot of water passing through a channel
cross-section every second (abbreviated CFS), also known as a “second-foot.”
Darcy’s Law: A law discovered by Henry Philibert Gaspard Darch
(1803-1858). His experiments showed that the velocity of flow through porous
media is proportional to the first power of the gradient.
Decree: An official document issued by a court or the State Board
of Control defining the priority, amount, use, and location of a water right
or plan of augmentation. When issued, the decree serves as a mandate to
the state engineer to administer the water rights involved in accordance
with the decree.
Deed: Legal document for conveyance of land from owner to new
owner. (See Water Right Deed).
Deep Percolation: The drainage of soil water by gravity below
the maximum effective depth of the root zone.
Dependable Yield: See Yield, firm.
Depletion: Net rate or quantity of water taken from a stream or
groundwater aquifer and consumed by beneficial and nonbeneficial uses. For
irrigation or municipal uses, the depletion is the headgate or well-head
diversion less return flow to the same stream or groundwater aquifer.
Digital Elevation Model: Computer file with elevations recorded
for the intersections of a fine-grained latitude/longitude grid; the digital
equivalent of a topographic base map; abbreviated DEM.
Direct Flow Right: A right defined under the terms of a permit
to beneficially use natural streamflow, as opposed to reservoir storage or
Discharge, or Rate of Flow: The volume of water passing a particular
point in a unit of time. Units of discharge commonly used include cubic
feet per second (cfs) or gallons per minute (gpm).
Ditch: A conduit cut into or built upon the surface of the ground
to transport water from a stream to a point of use away from the stream.
Divert: To remove water from its natural course or location, or
impound water in its natural course or location, by means of a ditch, canal,
flume, reservoir, bypass, pipeline, conduit, well, pump, or other structure
Diversion Records: Record of the instantaneous flow in cubic feet
per second for a ditch or other diversion structure. Compiled by the district
water commissioner, ditch rider, or other water official, diversion records
are generally on file and available for review at the State Engineer’s Office.
Domestic Water Use: Water used for normal (non-commercial) household
purposes, such as drinking, food preparation, bathing, washing clothes and
dishes, flushing toilets, and watering lawns and gardens. Also called residential
water use or domestic withdrawals. The water may be obtained from a public
supply or may be privately supplied.
Drainage Area: The surface area contributing to a drainage basin,
inside which all surface waters will flow to a common outlet.
Drawdown: The drop in water table elevation from an initial stable
configuration, generally caused by pumping.
Due Diligence: The effort necessary to bring an intent to appropriate
into fruition. Due diligence does not require unusual effort or expenditures,
but only such constancy in the pursuit of the undertaking as is usual with
those in like enterprises. Actions which demonstrate a good faith intention
to complete the undertaking within a reasonable time.
Duty of Water: The amount of irrigation water required to mature
a particular type of crop in a specific location. It includes consumptive
use, evaporation, and seepage from ditches and canals, and the water eventuallyreturned
to streams by percolation and surface runoff, usually expressed in acre-feet
per acre, or cfs per unit ofapplication area.
Effective Precipitation: The amount of rain that falls during
the growing season and is available for growth of crops. Effective precipitation
is a portion of the total rain that falls during the growing season and is
a function of the type of soil, the time period in which each rain falls,
and its intensity. Effective precipitation is usually less than precipitation
measured at a given point.
Endangered Species: Under provisions of the federal Endangered
Species Act of 1973, a species that is in danger of extinction throughout
all or a significant portion of its range.
Enlargement: A subsequent water right awarded to a ditch or structure
enlarging the amount of water granted originally. More than one enlargement
may be awarded to a ditch or structure and each enlargement will have a priority
related to the date it was filed for appropriation.
Eutrophication: Aging process by which nutrient additions to a
water body initially lead to additional growth of aquatic organisms which
may eventually consume all available dissolved oxygen.
Evaporation: The physical process by which a liquid or solid is
transformed to the gaseous state which, in irrigation, usually is restricted
to the change of water from liquid to gas.
Evapotranspiration: The combined processes by which water is transferred
from the earth surface to the atmosphere; evaporation of liquid or solid
water plus transpiration from plants (See Consumptive Use).
Expiration (Expired Permit): The status of an invalid water permit
when the permittee has not complied with the notice requirements within the
time specified on the permit. An expired permit is not a property right
of the current landowner.
Floodplain: An area adjacent to a stream or other water course
which is subject to flooding.
Flood Stage: Situation when flow of water exceeds the capacity
of the incised channel of a creek or river and overflow of the natural banks
Flowing Well: A well from an artesian aquifer in which the water
is under sufficient pressure to rise above the ground surface.
Flume: A type of in-channel measuring device of known cross-sectional
area in a ditch or river. Also used to describe the facility used to bridge
flowing water across another channel, depression, or other rough terrain.
Forfeiture: Failure to use a water right for the statutorily provided
period of time, or failure to timely file the notices required by the permit.
Freeboard: The additional height on a dam or other water control
structure to provide against overtopping due to wave action and excess inflow.
Futile Call: A situation in which a junior priority will be permitted
to continue to divert in spite of demands by a senior appropriator in the
same watershed, because to curtail the junior from diversion would not effectively
produce water for beneficial use by the senior.
Gage: (1) An instrument used to measure magnitude or position;
gages may be used to measure the elevation of a water surface, the velocity
of flowing water, the pressure of water, the amount of intensity of precipitation,
the depth of snowfall, and so on. (2) The act or operation of registering
or measuring magnitude or position. (3) The operation, including both field
and office work, of measuring the discharge of a stream of water in a waterway.
Gage Height: The height of the water surface above the gage datum.
Gage height is often used interchangeably with the more general term, stage,
although gage height is more appropriate when used with a gage reading.
Gaging Station: A particular site on a stream, canal, lake, or
reservoir where systematic observations of gage height or discharge are made,
generally with permanently installed continuous-recording instrumentation.
Grab Sample: A water quality sample taken at random.
Gradient: A slope of the water table tending to cause the flow
of groundwater. Also the slope of a ditch, canal, pipeline, or surface of
Groundwater: Groundwater is usually defined as any water not visible
on the surface of the ground under natural conditions.
Groundwater, Confined: Groundwater under pressure significantly
greater than atmospheric, with its upper limit the bottom of a bed with hydraulic
conductivity distinctly lower than that of the material in which the confined
Groundwater Divide: A line of a water table on either side of
which the water table slopes downward. It is analogous to a drainage divide
between two drainage basins on a land surface.
Groundwater Mining: The pumping of groundwater from a basin where
the safe yield is very small, thereby extracting groundwater which accumulated
over a long period of time. It occurs when withdrawals exceed replenishment
or when replenishment is negligible.
Groundwater Overdraft: Pumpage of groundwater in excess of safe
Groundwater, Perched: Groundwater that is separated from the main
body of groundwater by unsaturated material.
Groundwater Recharge: Inflow to a groundwater reservoir.
Groundwater Reservoir: An aquifer or aquifer system in which groundwater
is stored. The water may be placed in the aquifer by either artificial or
Growing Season: That portion of the year, usually May through
October, that the plants are consuming water and nutrients, or, in irrigation,
the period between spring and fall killing frosts.
Head: 1. The pressure created from the weight of water.
2. Locally, an amount of irrigation water that can be supplied through
Headgate: A physical structure on a stream, (reservoir, canal,
ditch or lateral), through which water is diverted into a smaller ditch,
a stream channel, a pipeline, or onto land.
Historic Use: The documented diversion and use of water by a water
right holder over a period of years.
Hydrologic Cycle: The circuit of water movement from the atmosphere
to the earth and return to the atmosphere through various stages or processes,
such as precipitation, interception, runoff, infiltration, percolation, storage,
evaporation, and transpiration.
Hydrology: Study of the distribution, movement and properties
Impermeable: Not permeable.
Impervious: An adjective describing a material through which water
either cannot pass or through which it passes with great difficulty.
Infiltration: Water moving into the ground from a surface supply
such as precipitation or irrigation.
Inflow: The quantity of water coming from all sources into a storage
facility or a channel at a given point.
Insolation: (Contracted from incoming solar radiation.) Solar
radiation received at the earth’s surface.
Instream Use: Any use of water which does not require diversion
from a water course or impoundment.
Instream Flow Rights: A doctrine used to preserve minimum river
or streamflows for fish and wildlife, recreation, water quality and scenic
beauty, among other public purposes. Such rights are limited to the use
of water within its natural course, not requiring diversion. In Wyoming,
instream flow rights are limited to fishery purposes.
Irrigation: The application of water to crops, lawns, and gardens
by artificial means to supplement natural precipitation. Water can be applied
by spreading, sprinkling, or dripping.
Irrigation District: In the United States, a cooperative, self-governing
public corporation set up as a subdivision of the state, with definite geographic
boundaries, organized to obtain and distribute water for irrigation of lands
within the district; created in District Court under authority of the state
legislature with the consent of a designated fraction of the landowners or
citizens and having taxing power.
Irrigation Efficiency: The ratio of the volume of water consumed
by irrigation as compared to the volume of water delivered. Efficiency
may be computed in terms of the water diverted at the ditch headgate or the
water delivered to the farm headgate. Overall efficiency is the product
of conveyance efficiency x application efficiency x use efficiency, expressed
Irrigation Return Flow: Applied water which is not consumptively
used and returns to a surface water or groundwater supply. In water right
litigation the definition may be restricted to measurable water returning
to the stream from which it was derived.
Irrigation Water Requirement: The quantity of water, exclusive
of effective precipitation, that is required from irrigation to meet crop
needs for full growth and maturation.
Isohyet: A line on the surface of the earth, as represented on
a map, connecting all points of equal precipitation. Also called isohyetal
line and isopluvial line.
Junior Rights: A junior water rights holder is one who holds rights
that are more recent than senior rights holders. All water rights are defined
in relation to other users, and a water rights holder only acquires the right
to use a specific quantity of water under specified conditions. Thus, when
limited water is available, junior rights are not met until all senior rights
have been satisfied.
Lag Time: The time from the center of a unit storm to the peak
discharge it generates at a point downstream; similarly, the time from the
daily maximum amount of snow being melted to the peak discharge it generates
at a selected point downstream. Also, the time it takes for the peak discharge
in a diurnal flow pattern to move from one point on a stream to another.
Lateral: A minor ditch or pipeline headgating off the main ditch
or pipeline used to direct water onto the land. A ditch may have many laterals,
depending on the amount of acreage irrigated, the slope of the land, and
the rate of seepage losses.
Law of the River: The name applied to the legal framework comprised
of interstate and interregional compacts, state and federal laws, Supreme
Court decisions, and international treaties which govern the distribution
of water from the Colorado River system.
Loss: The difference between the amount of water that is actually
placed on the land and the amount of water that was physically diverted to
the headgate. Losses usually are from seepage and evaporation.
Manning Equation: An equation developed for mathematical calculation
of flow volume in open channels.
Manning’s equation is written as follows:
v = 1.486 r 2/3S 1/2
Q = 1.486 ar 2/3 S ½
Q = discharge in cubic feet per second
a = the cross section of flow area in square feet,
v = the velocity in feet per second,
n = a roughness coefficient,
r = the hydraulic radius = area (a) ? wetted perimeter (p)
s = the slope of the energy gradient.
The value of the roughness coefficient, n, varies according to the
physical roughness of the sides and bottom of the channel and is influenced
by such factors as channel curvature, size and shape of cross section, alinement,
and type and condition of the material forming the wetted perimeter.
Values of n commonly used in design of artificial channels are as follows:
||Values of n
straight and uniform
straight and uniform
|Neat cement lined
Mean Annual Flow: The average flow over the 12 month period of
a given creek or river at a particular gage site.
Miner’s Inch: The term miner’s inch, formerly used in hydraulic
mining and irrigation in the western United States, is practically obsolete.
It is defined as the quantity of water which will flow through an orifice
1 inch square under a stated head which varies from 4 to 6 ½ inches
in different localities. The use of this unit has led to much confusion;
its value in terms of cubic feet per second has been fixed by statute in
most of the western states, as follows:
(1) 50 miner’s inches - 1 second foot in Idaho, Kansas, Nebraska, New Mexico,
North Dakota, South Dakota, Utah, Washington, and Southern California.
(2) 40 miner’s inches - 1 second foot in Arizona, Montana, Nevada, Oregon,
and Northern California.
Natural Flow: The amount of water in a given channel that arise
from sources other than storage releases or transbasin diversions. The amount
available for diversion to direct flow water rights.
Nonconsumptive Use: A use of water that does not reduce the supply,
such as for hunting, fishing, boating, water-skiing, swimming and power generation.
Nontributary Groundwater: Water that is not part of a natural
surface stream as established through geologic and hydrologic facts. The
factual determination of nontributary usually involves the length of time
the impact of withdrawal would take to reach the stream and the amount of
impact relative to the total volume of surface flow impacted.
Original Right or Original Supply: The first right awarded to
a ditch or storage structure which may be augmented by a later secondary,
supplemental or additional supply.
Outflow: Movement of water out of a drainage basin or reservoir.
Paper Right: A document purporting to be legal proof of a water
right, but which may have lost its legal validity because of abandonment
or lack of due diligence in perfecting the right.
Parshall Flume: A specifically-designed measuring device for flow
in a ditch or other water diversion or creek.
Peak Flow Gage: A streamflow gage which records the peak flows
from a streamflow event.
Permeability: A term used to describe the ability of water or
other liquid to move through a porous formation under the action of a gradient.
The facility with which a fluid will move through a formation is greater
for some than for others. For a given bed, the permeability is expressed
by a constant K representing the flow through unit in unit time under the
influence of a unit gradient. The flow is expressed in terms of entire water.
Phreatophyte: A plant growing in or along a waterway which consumes
Piezometer: An instrument which measures hydraulic pressure
Porosity: Amount of pore spaces in a geologic unit, usually expressed
as a ratio of volume of pore spaces to total volume of rock.
Pot Hole: A natural depression which stores water. Generally
associated with glaciated areas such as the northern Great Plains (Dakotas,
prairie provinces of Canada).
Potential Evapotranspiration: The rate of which water, if available,
would be removed from the soil and plant surface expressed as the rate of
latent heat transfer per square centimeter or depth of water. For comparative
purposes potential evapotranspiration refers to a well-watered crop like
alfalfa (lucerne) with 30 to 50 centimeters of top growth and about 100 millimeters
of fetch under given climatic conditions unless otherwise defined.
Precipitation: Moisture that falls to the earth’s surface.
Preferred Use: In Wyoming, includes the following uses, in order:
- Drinking water for both humans and livestock;
- Water for municipal purposes;
- Water for steam engines and general railway use; water for cooking,
laundering, bathing, and refrigerating (including the manufacturing of ice);
water for steam and hot-water heating plants, steam power plants;
- Water for industrial purposes.
When water rights are acquired through court condemnation, the former
use of water can be changed to a higher preferred use. Irrigation is not
a preferred use except to hydropower.
Prior Appropriation: A term describing the general process by
which limited water is distributed among several claimants. In the West
the first person to file and use the water beneficially gets the first water
right, whether or not that person owns land next to the river or lake from
which the water is diverted.
Priority: The relative seniority of a water right as determined
by its claim date or filing date. Other factors are sometimes involved in
determining priority. The priority of a water right determines its ability
to divert in relation to other rights in periods of limited supply.
Proof Inspection: The State’s visual verification that a water
permit has been developed and beneficially using water within the terms of
Production (Well): The total volume of well flow counted from
the time of initiation of flow.
Property Right: In water, the point at which a permit to use water
is developed to actual water use and the permittee files notice of beneficial
use. Before that point, the permit is not a property right attaching to
Public Interest: An interest or benefit accruing to society generally,
rather than to any individuals or groups of individuals in the society.
Public Supply: Water withdrawn for all uses by public water suppliers
and delivered to users that do not supply their own water. Water suppliers
provide water for a variety of uses such as domestic, commercial, industrial,
and public water use.
Rainshadow: Phenomena caused when major topographic features create
a barrier to moisture-laden air; air is warmed as it descends on the lee
side of the barrier resulting in warm-dry conditions.
Reach: A specified length of a stream or channel.
Recharge: Process by which water is added to the zone of saturation,
as recharge of an aquifer.
Recurrence Interval: Expected time interval between hydrologic
events of a given magnitude (e.g., 100-year peak flow, 10-year/7-day low
Reserved Water Rights: This class of water rights is a judicial
creation derived from “Winters v. United States” (207 U.S. 564, 1907) and
subsequent federal case law, which collectively hold that when the federal
government withdraws land from general use and reserves it for a specific
purpose, the federal government by implication reserves the minimum amount
of water unappropriated at the time the land was withdrawn or reserved to
accomplish the primary purpose of the reservation. Federal reserved water
rights may be claimed when Congress has by statute withdrawn lands from the
public domain for a particular federal purpose or where the President has
withdrawn lands from the public domain for a particular federal purpose pursuant
to congressional authorization. Examples are Indian reservations, national
forests, national parks/monuments.
Reservoir: A pond, lake, or basin, either natural or artificial,
used for the storage, regulation, and control of water.
Reservoir Capacity: The amount of water usually measured in units
of acre-feet that can physically be retained in a storage reservoir.
Return Flow: Unconsumed water which returns to its source or some
other water body after its diversion as surface water or its extraction from
the ground. Also, tailwater, drainage.
Riparian: Pertaining to the banks of a stream, lake, or body of
Riparian Land: Land which abuts upon the banks of a stream or
other natural body of water.
Riparian Rights: A system used primarily in the eastern states
to determine who has rights to water. The riparian system gives water rights
to the owners of the lands through which water flows. (See Prior Appropriation)
Riparian Vegetation: Vegetation growing on the banks of a stream
or other body of surface water.
River Basin: The area drained by a river and its tributaries.
River Stage: The instantaneous elevation of the water surface
at a specified station above some arbitrary zero datum.
Runoff: Precipitation that flows to and in surface streams; renewable
Salinity: The amount of dissolved solids in water, sometimes referred
to as Total Dissolved Solids (TDS), as well as Soluble Mineral Content (SMC).
500 ppm is acceptable for drinking water; plant damage occurs at 800-1000
Secchi Disc: A measuring device for determining water clarity.
Secondary Supply: Attachment by permit of a reservoir storage
allocation to specific lands or area/points of use.
Sediment: Unconsolidated particles of clay, silt, sand, gravel,
cobbles and boulders.
Seepage: (1) The slow movement of water through small cracks,
pores, interstices of a material into or out of a body of surface or subsurface
water. (2) The loss of water by infiltration into the soil from a canal,
reservoir, or other body of water, or from a field. Seepage is generally
expressed as flow volume per unit time. During the process of priming of
canals, the loss is called absorption loss.
SNOTEL: Specific remote telemetric instrumentation maintained
by the Natural Resources Conservation Service for comparing snowpack conditions
at various sites within a season or over many years.
Snowpack: The amount of snow accumulating during the winter months.
May be reported in height, water equivalency or percent of average.
Soil Moisture: Water held in the soil.
Solar Radiation: The total electromagnetic radiation emitted by
the sun (see Insolation).
Spillway: The facility associated with a storage reservoir or
diversion structure to allow for the bypass of water when the reservoir or
ditch is full or in flooding conditions.
Spring Box: A device that collects and/or diverts water from a
Spring Development: The diversion of water from a naturally flowing
spring or the enhancement of flow from a spring.
Staff Gage: A graduated scale used to indicate the height of the
water surface in a stream channel, reservoir, lake, or other water body.
Stage: The height of a water surface above an established datum
plane (see Gage Height).
State Engineer: The chief executive officer in the executive department
of the state government who administers water rights.
Stilling Well: A vertical casing which is connected to a source
of water to still the turbulence on the natural surface as water levels rise
and fall with flow in a channel so the water stage can be accurately measured.
Storage Right: A right defined in terms of the volume of the water
which may be diverted from the flow of the stream and stored in a reservoir
or lake to be released and used at a later time either within the same year
or a subsequent year.
Stream: Body of water flowing in a channel; may be classified
in relation to flow frequency:
Ephemeral: Stream that only flows water during storm-period
events and whose channel is above the water table at all times.
Intermittent: Stream that flows water between 1 and 3 seasons per
year, or one that flows water over most of its course.
Perennial: Stream that flows water continuously.
Streams may also be classified in relation to groundwater:
Insulated: Stream that neither contributes to nor receives
water from the zone of saturation because it is separated by an impermeable
Gaining: Stream that receives water from the zone of saturation (effluent
seepage or bank storage).
Losing: Stream that contributes water to the zone of saturation (influent
seepage or bank storage).
Perched: Either a losing stream or insulated stream that is separated
from the underlying groundwater by a zone of aeration.
Sublimation: Process by which water vapor is converted into solid
water (snow/ice) directly without passing through the liquid phase.
Supplemental Supply: An additional irrigation water supply water
right from a separate stream which supplements the original surface water
Surface Area of Reservoir: The 2 dimensional area covered by water
stored in a reservoir, usually measured in units of acres.
Territorial Water Rights: In Wyoming, water rights with priority
dates before July 1, 1890 (year of statehood).
Thalweg: The thread of maximum flow through the cross-section
of a flowing stream. It moves from one bank toward the other bank in meandering
Total Consumptive Use: The amount of water, regardless of its
source, used by the crops during the growing season. It is the amount of
water that is physically removed from the stream’s system and is not available
in return flows for other users on the stream.
Total Dissolved Solids (TDS): Dry weight of dissolved material,
organic and inorganic, contained in water that will not be removed by a 0.45
micron filter; usually described in units of mg/1.
Total Suspended Sediments (TSS): A water quality measure of the
sediments that are suspended within a water body.
Triple Divide: Common point along the drainage divide for three
Trans-Basin Diversion: The removal of the water of a natural stream
from its natural basin of origin into the natural basin of another stream
across a hydrographic divide.
Transfer: State authorization for change in use, change in place
of use, or change in point of diversion and means of conveyance.
Transpiration: The process by which water in plants is transferred
as water vapor to the atmosphere.
Tributary Groundwater: Seepage, underflow, and percolating water
that will eventually become part of the natural surface stream. A natural
stream’s waters include water in the unconsolidated alluvial aquifer of sand,
gravel, or other sedimentary materials, and all other waters hydraulically
connected thereto, which can influence the rate or direction of movement
of the water in that alluvial aquifer or natural stream.
Unadjudicated: A water right permit before it has been publicly
recognized by proof inspection and advertisement. See adjudicated.
Unconfined Aquifer: An aquifer in which the water table serves
as the upper surface of the zone of saturation.
Ungaged Streams: Creeks or rivers which have not been equipped
with measuring devices. Equations exist for estimating the flow from these
streams based upon parameters such as drainage areas.
Vapor Pressure: The partial pressure of water vapor in the atmosphere.
Velocity: The speed of water as it travels through a channel or
Virgin Flow: The flow of a river that would occur in the absence
of human activities; synonymous with native supply.
Volume: A specific quantity of water generally expressed in terms
of acre-feet. An acre-foot is defined as the amount of water required to
cover 1 acre of land to a depth of 1 foot and is equivalent to 43,560 cubic
feet, or 325,850 gallons.
Walton Rights: Reserved water rights for non-Indian successors
on Indian reservations.
Water Commissioner: Public officials under the direction of the
division superintendents who carry out the detailed daily administration
of the waters in portions of each water division.
Water Court: In Colorado, special division of a district court
with a district judge, called the water judge, to deal with certain specific
water matters principally having to do with adjudication and change of water
rights. In Wyoming, it is initially handled by the executive branch of state
government, instead of the judicial branch, under the Board of Control.
Water Development: The process of building diversion, storage,
pumping, and/or conveyance facilities to apply water to beneficial use.
Water District or Water Commissioner District: A subdivision of
a water division, usually defined by drainage basin.
Water Division: One of four statutorily-described divisions of
the State of Wyoming correlating to their inclusion in major river systems
of the United States.
Water Equivalent: A measurement of the moisture contained in snowpack.
Water Right: A right to use, in accordance with its priority,
a certain portion of the waters of the state by reason of the specific appropriation
of the same.
Water Right Deed: (Obsolete reference) Conveyance from the landowner
of the right to seek, from the state, a change in place of use to a new owner.
Watershed: The area from which water drains to a single point.
Water Table: The upper limit of the completely saturated material
in an aquifer.
Water Well: A water well is a hole or shaft, usually vertical,
excavated in the earth for bringing groundwater to the surface. Occasionally
wells serve other purposes, such as subsurface exploration and observation,
artificial recharge, and disposal of wastewater. Many methods exist for
constructing wells; selection of a particular method depends on the purpose
of the well, the quantity of water required, depth to groundwater, geologic
conditions, and economic factors. Shallow wells are dug, bored, driven or
jetted; deep wells are drilled by cable tool or rotary methods.
Water Year: The 12-month period October 1st through September
30th, generally correlating with the snowpack and subsequent growing season.
The water year is designated by the calendar year in which it ends and which
includes 9 of the 12 months. Thus, the year ending September 30, 1959, is
the 1959 water year.
Weir: A certain kind of water flow measuring device.
Yield: (1) The quantity of water expressed either as a continuous
rate of flow or as a volume per unit of time (AF per year), which can be
collected for a given use or uses from surface or groundwater sources on
a watershed. The yield may vary with the proposed use, the plan of development,
and also economic considerations. Yield is fairly synonymous with water
crop. (2) Total runoff. (3) The streamflow in a given interval of time
derived from a unit area of watershed. It is determined by dividing the
observed streamflow at a given location by the drainage area above that location
and is usually expressed in cubic feet per second per square mile. See also
Yield, Firm; Yield Perennial; Yield, Safe.
Yield, Average Annual: The average annual supply of water produced
by a given stream or water development.
Yield, Firm: The maximum annual supply of a given water development
that is expected to be available on demand, with the understanding that lower
yields will occur in accordance with a predetermined schedule or probability.
Yield, Perennial: The amount of usable water of a groundwater
reservoir that can be economically withdrawn and consumed each year for an
indefinite period of time. It cannot exceed the natural recharge to that
groundwater reservoir and ultimately is limited to the maximum amount of
discharge that can be utilized for beneficial use.
Yield, Safe: With reference to either surface or groundwater supply,
the rate of diversion or extraction for consumptive use which can be maintained
indefinitely, within the limits of economic feasibility, under specified
conditions of water supply development (see also Yield, Perennial).
Yield, Water Right: The volume of water diverted by a water right.
Yield may be expressed as an average for a period of years (average yield)
or as the yield of one selected year representing the lowest or critical
amount of water provided (critical year yield). Yield also may refer to
diversion at the headgate (headgate yield) or at the farm turnout where it
si applied to irrigation (farm yield). The difference between headgate yield
and farm yield is the amount of water lost to seepage and other causes related
to the conveyance of water through the ditch.