ARM 36.12.115
ARM 36.12.115. WATER USE STANDARDS
Cite as Mont. Admin. R. 36.12.115
(1) A water right has several elements, one of which is the amount of water that is used for each purpose described in the right. A reasonable amount of water will vary with the type and location of the use and will depend on various circumstances such as:
(a) soil conditions;
(b) method of conveyance;
(c) topography;
(d) climate;
(e) system efficiency; or
(f) other conditions affecting the particular use.
(2) The department will use the following standards when reviewing notices or applications for new uses of water:
(a) for domestic use, for one household, 1.0 acre-foot per year of water for year-round use;
(b) for lawn, garden, shrubbery, and shelterbelts, 2.5 acre-feet per acre per year;
(c) for stockwater, a consumptive use of 15 gallons per day or .017 acre-foot per year per animal unit. Animal unit equivalencies for water consumption are set out in ARM 36.12.101 and the water conversion table, Form No. 615;
(d) fire protection water needs shall be determined by the type of equipment used, diversion rate, the size of the area to be covered, the frequency of the water use and must be explained and documented.
(e) For irrigation, the following table applies:
Irrigation Standards
Climatic Area 1
Acre Feet per Acre
I
II
III
IV
V
Sprinkler Irrigation
70% Efficiency
2.63 - 3.04
2.30 - 2.69
2.08 - 2.41
1.76 - 2.07
1.26 - 1.48
Level Border
60% Efficiency
Design Slope Level
3.07 - 3.55
2.69 - 3.15
2.43 - 2.81
2.06 - 2.41
1.47 - 1.73
Graded Border
70% Efficiency
Slope Group
Design Slope .10%
Design Slope .20%
Design Slope .40%
2.63 - 3.04
2.30 - 2.69
2.08 - 2.41
1.76 - 2.07
1.26 - 1.48
Graded Border
65% Efficiency
Design Slope .75%
Design Slope 1.5%
2.84 - 3.28
2.48 - 2.90
2.24 - 2.59
1.90 - 2.23
1.36 - 1.60
Graded Border
60% Efficiency
Design Slope 3.0%
3.07 - 3.55
2.69 - 3.15
2.43 - 2.81
2.06 - 2.41
1.47 - 1.73
Furrow
70% Efficiency
Design Slope .10%
Design Slope .20%
Design Slope .40%
2.36 - 2.74
2.11 - 2.44
1.87 - 2.16
1.39 - 1.70
NA
Furrow
65% Efficiency
Design Slope .75%
2.54 - 2.95
2.27 - 2.63
2.02 - 2.33
1.50 - 1.83
NA
Furrow
60% Efficiency
Design Slope 1.5%
2.75 - 3.19
2.46 - 2.85
2.19 - 2.52
1.62 - 1.98
NA
Contour Ditch
60% Efficiency
Design Slope .75%
3.07 - 3.55
2.69 - 3.15
2.43 - 2.81
2.06 - 2.41
1.47 - 1.73
Contour Ditch
55% Efficiency
Design Slope 1.5%
Design Slope 3.0%
3.35 - 3.87
2.93 - 3.43
2.65 - 3.07
2.24 - 2.63
1.60 - 1.88
Contour Ditch
45% Efficiency
Design Slope 6.0%
4.10 - 4.73
3.58 - 4.19
3.24 - 3.75
2.74 - 3.22
1.96 - 2.30
1 The irrigation climatic areas are identified in the 1986 Irrigation Climatic Areas of Montana map. Climatic area I is high consumptive use, climatic area II is moderately high consumptive use, climatic area III is moderate consumptive use, climatic area IV is moderately low consumptive use, and climatic area V is low consumptive use.
(3) A permit is required when a reservoir is proposed to include fire protection purposes and the volume of water reasonably needed for fire protection must be explained and must reference reliable industry sources.
(4) For fire protection reservoirs located within a basin closure area, evaporation losses must be made up from nontributary water sources or addressed in a mitigation plan.
(5) The flow rate and volume of water for any uses not listed in this rule must be calculated, explained, and documented based on the beneficial use and operation of the project.
(6) Deviations outside the standards will require information supporting the requested amount.