Hydrohistorian
Colorado water glossary
A
Abandonment
Termination from intent to permanently discontinue use; nonuse tolled for conservation programs.
Absolute water right
A right whose water has been diverted and placed to beneficial use.
Acre-foot
43,560 ft³ or 325,851 gallons.
Adjudication
Water-court process confirming a claim and fixing amount and priority.
Adjudication date
Date the court awarded the decree (pre-1969 signature date; post-1969 last day of filing year).
Administration number
DWR's XXXXX.YYYYY rank: days from 1849-12-31 to previous-adjudication date and appropriation date.
Alternate point of diversion
A change adding alternate/supplemental points; approved only without injury.
Alternative transfer methods
CWCB's umbrella for non-permanent ag-to-urban transfers.
Appropriation
Applying waters of the state to beneficial use under legal procedures, excluding speculative transfers.
Appropriation date
Date water was first applied to beneficial use or an overt act showed intent; decreed by the court.
Augmentation vs exchange
Exchanges operate between decreed points via substitute supply; augmentation replaces out-of-priority depletions; both need decrees.
B
Beneficial use
The amount reasonable and appropriate, under reasonably efficient practices, to accomplish without waste the lawful purpose.
C
"Can and will"
Conditional applicant must show water can and will be diverted and used within a reasonable time.
Call
A senior's request that the division engineer curtail juniors; "the administrative status of the natural stream."
Change of water right
Change in type, place, time of use, point or means of diversion, or storage, keeping the priority.
Colorado River Compact
7.5 maf/yr to each basin; Upper Basin not to deplete Lee Ferry below 75 maf in any 10 consecutive years.
Compact
Agreement between states, approved by legislatures and Congress, apportioning an interstate river.
Compact call
Hypothetical Lower Basin demand forcing Upper Basin curtailment; never invoked.
Conditional water right
Right to perfect a right with a certain priority upon completing the appropriation with reasonable diligence.
Consumptive use
Water diverted that does not return to the stream.
Curtailment
Division engineer's order to discontinue diversions not needed for beneficial use or required by seniors.
D
Decennial abandonment list
Division engineers publish every tenth year (from 1990) a list of absolute rights deemed abandoned, subject to protest.
Decree
Court order defining priority, amount, source, point of diversion, and use.
Decreed vs actual diversion
Decreed amount is the ceiling; changes are limited to actual historical use.
Denver Basin aquifers
Laramie-Fox Hills, Arapahoe, Denver, Dawson; permitted on a 100-year aquifer life.
Designated groundwater basin
Area where groundwater is not available for decreed surface rights, established by the Commission.
Developed water
Foreign, nontributary, or other water newly added; reuse right personal to the developer.
Direct-flow right
Right to divert stream flow for immediate use, in cfs.
Diversion
Removing or controlling water from its natural course by ditch, canal, reservoir, well, pump, etc.
Diversion record
DWR's structure-linked record of water diverted/released, in HydroBase.
Division engineer
Appointed per division; curtailment orders; priority tabulations.
Dominion and control
Developer keeps dominion over developed water in a watercourse until released.
Dry-up covenant
Recorded restriction barring irrigation of historically irrigated land after a change.
Duty of water
Rate/volume per acre reasonably required for irrigation.
E
Exchange
Delivering substitute water to a senior downstream and taking an equal amount upstream, without injury.
Exempt well
≤15 gpm household/livestock/≤1-acre garden (≤3 dwellings), fire, monitoring; exempt from priority administration.
F
First in time, first in right
§6: "Priority of appropriation shall give the better right as between those using the water for the same purpose."
Free river
Supply meets all diversions so no call is required; waste still prohibited.
Fully consumable water
Imported or developed water consumable to extinction.
Futile call
Curtailment must be rescinded if it would not make water available to seniors at the time and place of need.
G
Gain/loss (transit loss)
Water lost between points; "a reasonable deduction for loss" set by the State Engineer.
H
Headgate
Owner-maintained control structure at the point of intake; specs 37-84-112.
Historical consumptive use
Quantified from actual historical use over a representative period of wet, dry, average years.
I
Imported (foreign) water
Water introduced from an unconnected system may be used to extinction.
Instream flow right
CWCB's exclusive authority to appropriate minimum streamflows and natural lake levels (1973).
Interruptible water supply agreement
Option where a lender stops using its right when the borrower exercises; max three years in ten.
J
Junior / senior
Ranked by priority date; seniors satisfied first.
M
Mutual ditch company
Special-statute corporation whose shares represent specific water rights.
N
Non-exempt well permit
Under 37-90-137; Denver Basin allocation 1%/yr.
Nontributary groundwater
100-year withdrawal depletes stream flow <0.1% of the annual withdrawal rate.
Not-nontributary
Denver Basin water whose withdrawal would deplete streams >0.1%; requires augmentation.
O
One-fill rule
A reservoir priority may fill once per year (Windsor Reservoir v. Lake Supply Ditch, 1908).
Over-appropriated
More decreed rights than supply; used but not defined in statute.
P
Paper water
Legal entitlement on paper versus wet water physically available.
Plan for augmentation
Program to increase supply via new points, pooling, exchanges, or substitute supplies.
Point / place / time of use
Decreed location of diversion and place/season of use; each a "change" element.
Postponement doctrine
Rights on applications filed in a year are junior to all rights on prior-year applications.
Prior appropriation
Constitutional rule that the right to divert unappropriated stream water for beneficial use "shall never be denied," ranked by priority.
Priority
The seniority date and relative rank among rights on a common source.
Priority date
Administratively, the later of the appropriation date or the previous adjudication date.
R
Reasonable diligence
Every sixth year a conditional owner must apply for a diligence finding or the right is abandoned.
Relation-back doctrine
A conditional right perfected with diligence carries the appropriation date of its first step.
Replacement water
Water supplied under a plan to offset out-of-priority depletions at the time and location required.
Republican River Compact
Allocates virgin water supply among CO/KS/NE; Colorado 54,100 af/yr.
Resume
Monthly summary of every application filed; opposition due by end of the second following month.
Return flow
Water reaching surface or ground water after release from the point of use.
RICD
Minimum streamflow between control structures, claimed by a governmental entity, for a reasonable recreation experience April 1–Labor Day.
Rio Grande Compact curtailment
Colorado delivers index-gage volumes at the state line with a 100,000 af debit cap; Division 3 curtails daily.
Rotational crop management contract
Changing irrigation rights by rotating which lands go unirrigated.
S
Salvaged water
Water freed by removing phreatophytes stays tributary (Shelton Farms).
State Engineer
Director of DWR; administers and distributes the state's waters, supervises division engineers, meets compact obligations.
Substitute water supply plan
State Engineer-approved temporary plan replacing all out-of-priority depletions.
T
Terms and conditions
Decree provisions imposed so a change or plan does not injure vested rights.
Transmountain diversion
Moving water across the Divide or between basins.
Tributary groundwater
Water in the alluvium and hydraulically connected water that can influence a natural stream; administered in priority.
W
Water bank
Division-level program for leasing, loaning, exchanging stored water.
Water commissioner
Field staff per water district; administers rights, records diversions.
Water court
The district court in each of seven water divisions, acting through a water judge, with exclusive jurisdiction over water matters.
Water district
Sub-division administered by a water commissioner. Count: SYNOPSIS 78; CSU 80 (disagree).
Water division
One of seven divisions by major drainage (1 South Platte … 7 San Juan/Dolores).
Water right
A right to use, in accordance with its priority, a portion of the waters of the state by reason of appropriation.
Waters of the state
Unappropriated water of every natural stream is public property, subject to appropriation.
WDID
DWR structure id: water district (2 digits) + structure number, 7 digits.
Well augmentation
Court-approved augmentation for wells (required for not-nontributary Denver Basin wells).
Winters doctrine / reserved rights
Reservations impliedly reserve water as of creation; McCarran Amendment lets state courts adjudicate.
Known disagreements, shown rather than settled: the number of water districts (DWR's 2016 synopsis says 78, CSU's glossary says 80; this site uses DWR's 78); the exempt-well threshold (15 gpm outside designated basins under 37-92-602, 50 gpm inside under 37-90-105); "instream flow" is CWCB's usage for what the statute calls "minimum streamflow". Report a problem →