Current through Register Vol. 63, No. 9, September 1, 2024
A number of terms are used in the statutes, ORS
537.505 -
537.795, prescribing the
management of ground water in Oregon. These rules define terms to qualify and
clarify the statutes. In all statutes and rules employed in the management of
ground water by the Water Resources Department and Commission, the following
definitions shall apply, unless the context requires otherwise:
(1) "Aquifer" means a water-bearing body of
naturally occurring earth materials that is sufficiently permeable to yield
useable quantities of water to wells and/or springs.
(2) "Critical Ground Water Area Boundary"
means a line established in a critical ground water area order on a map that
surrounds an area in which one or more of the statutory criteria for critical
area declaration are met and which is located either:
(a) Physically by coincidence with natural
features such as ground water reservoir boundaries, hydrologic barriers, or
recharge or discharge boundaries; or
(b) Administratively by surrounding an
affected area when that area does not coincide with an area bounded by natural
features.
(3) "Customary
Quantity" means the rate or annual amount of appropriation or diversion of
water ordinarily used by an appropriator within the terms of that
appropriator's water right.
(4)
"Declined Excessively" means any cumulative lowering of the water levels in a
ground water reservoir or a part thereof which:
(a) Precludes, or could preclude, the
perpetual use of the reservoir; or
(b) Exceeds the economic pumping level;
or
(c) Constitutes a decline
determined to be interfering with:
(A) A
surface water diversion having a priority date senior to the priority dates of
the causative ground water appropriations; or
(B) A surface water body that has been
administratively withdrawn with an effective date senior to the priority dates
of the causative ground water appropriations unless the causative ground water
appropriations are for uses that are exceptions to the withdrawals;
or
(C) An adopted minimum stream
flow or instream water right, or closure having an effective date senior to the
priority dates of the causative ground water appropriations; or
(D) A surface water body which has a
classification that is senior to the priority date of the causative ground
water appropriation(s) and the use or uses to which the ground water is being
put are not included in the classification.
(d) Constitutes a lowering of the annual high
water level within a ground water reservoir, or part thereof, greater than 50
feet below the highest known water level; or
(e) Results in ground water pollution;
or
(f) constitutes a lowering of
the annual high water level greater than 15% of the greatest known saturated
thickness of the ground water reservoir. the saturated thickness shall be
calculated using pre-development water levels and the bottom of the ground
water reservoir, or the economic pumping level, whichever is
shallower.
(5) "Economic
Pumping Level" means the level below land surface at which the per-acre cost of
pumping equals 70 percent of the net increase in annual per-acre value derived
by irrigating. (The value is to be calculated on a five year running average of
the per-acre value of the three, if there are that many, prevalent irrigated
crops in the region minus the five year running average of the per-acre value
of the three, if there are that many, prevalent regional non-irrigated
crops.)
(6) "Excessively Declining
Water Levels" (Note: "Excessively" as used in ORS
537.730(1)(a)
is taken to modify both "are declining" and "have declined") means any ongoing
lowering of the water level in a ground water reservoir or part thereof which:
(a) Precludes, or could preclude, the
perpetual us of the reservoir; or
(b) Represents an average downward trend of
three or more feet per year for at least 10 years; or
(c) Represents, over a five year period, an
average annual lowering of the water level by 1% or more of the initial
saturated thickness as determined by observation or investigation in the
affected area; or
(d) Results in
water quality deterioration.
(7) "Overdraw" means to artificially produce
water, in any one year period, from a ground water reservoir, or part thereof,
at an annual rate that:
(a) Exceeds the
average annual recharge to that ground water supply over the period of record;
or,
(b) Reduces surface water
availability resulting in:
(A) One or more
senior appropriators being unable to use either their permitted or customary
quantity of surface water, whichever is less; or
(B) Failure to satisfy an adopted minimum
streamflow or instream water right with an effective date senior to the
causative ground water appropriation(s).
(c) Reduces the availability of surface
waters that have been:
(A) Withdrawn with an
effective date senior to the priority dates of the causative ground water
appropriations; or
(B)
Restrictively classified with an effective date senior to the priority date(s)
of the causative ground water appropriations.
(8) "Substantial or Undue Interference" means
the spreading of the cone of depression of a well to intersect a surface water
body or another well, or the reduction of the ground water gradient and flow as
a result of pumping, which contributes to:
(a)
A reduction in surface water availability to an extent that:
(A) One or more senior surface water
appropriators are unable to use either their permitted or customary quantity of
water, whichever is less; or
(B) An
adopted minimum streamflow or instream water right with an effective date
senior to the causative ground water appropriation(s) cannot be
satisfied.
(b) The
ground water level being drawn down to the economic level of the senior
appropriator(s); or
(c) One or more
of the senior ground water appropriators being unable to obtain either the
permitted or the customary quantity of ground water, whichever is less, from a
reasonably efficient well that fully penetrates the aquifer where the aquifer
is relatively uniformly permeable. However, in aquifers where flow is
predominantly through fractures, full penetration may not be required as a
condition of substantial or undue interference.
(9) "Substantial Thermal Alteration" means
any change in water temperature of a groundwater reservoir, or a part thereof,
which:
(a) Precludes, or could preclude, the
perpetual heating or cooling use of the groundwater reservoir; or
(b) Constitutes a change in the mean annual
temperature within a groundwater reservoir, or part thereof, greater than 25
percent of the highest recorded naturally occurring Celsius (C)
temperature.
(10)
"Substantial Thermal Interference" means the spreading of the radius of thermal
impact of a low-temperature geothermal production well or low-temperature
geothermal injection well to intersect a surface water body or another well, or
the reduction of temperature or heat flow as a result of pumping or injection,
which contributes to change in groundwater or surface water temperature to an
extent that one or more senior appropriators of the low-temperature resource
are unable to use water for the purpose(s) designated in the associated water
right.
(11) "Wasteful Use (of
ground water)" means any artificial discharge or withdrawn of ground water from
an aquifer that is not put to a beneficial use described in a permit or water
right, including leakage from one aquifer to another aquifer within a well
bore.
Stat. Auth.: ORS 537
Stats. Implemented:
