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The probability of a water shortage is based on
estimates of river basin runoff from monthly USDA NRCS
Idaho Water Outlook Reports, historical basin wide
reservoir storage accumulation during drought years, the
previous year’s October 31st reservoir storage carry
over, and an irrigation district’s historical storage
water requirements during non-drought years. An
irrigation district’s storage water allocation is based
on the amount of basin wide storage water and not on an
individual irrigation district’s account, thus the
results do not reflect specific carry over amounts of an
irrigation district. The probability of a water
shortage may be greater or less depending upon actual
storage water carry over for a specific irrigation
district. The approach does not directly consider
winter water savings contracts for storage held by some
irrigation districts. However, these storage
contracts fill every year and are reflected in the
historical data used to estimate storage water allocation.
How well the predictions reflect a particular irrigation
district’s situation should be evaluated by consulting
with the District Manager.
The severity of a water shortage represents an
upper limit of how substantial a shortage in storage water
allocation could be for an irrigation district.
Severity is calculated as the maximum expected shortfall
in storage water required for an irrigation district
divided by the irrigation district mean annual diversion.
The severity represents an extreme upper limit to a water
supply shortage that has a remote chance of occurring but
serves to cap the magnitude of the situation. Any
water shortage will likely be much less than that
represented by the severity.
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The values represented in the table below are based
entirely on historical data and mathematical relationships
that may not necessarily fit every irrigation district’s
situation. How well the predictions reflect a
particular irrigation district’s situation should be
evaluated by consulting with the District Manager.
These estimates are merely a guide for risk management
planning and should not be used for any purpose other than
risk management planning.
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Table shows the canal predictions of
water shortage for each month of 2005. The first column is the
estimated probability that a shortage will occur. The second
column is the estimated severity of that shortage.
Canals that irrigate less than
2000 acres or canals that are part of larger systems are not
predicted, look at the larger system if possible.
Monthly data will be added as the
streamflow predictions are published, usually by the 10th
of the month.
Water District 1
(Upper Snake above Twin Falls)
Boise Basin
Other Districts
|
District 1
Upper Snake
|
January,
2005 |
February,
2005 |
March,
2005 |
April,
2005 |
| Probability
of a Shortage |
Severity |
Probability
of a Shortage |
Severity |
Probability
of a Shortage |
Severity |
Probability
of a Shortage |
Severity |
| A
& B Irrigation |
16
% |
43
% |
20
% |
45
% |
51
% |
72
% |
31% |
47% |
| Aberdeen |
38
% |
42
% |
47
% |
43
% |
86
% |
54
% |
71% |
44% |
| Blackfoot |
13
% |
2
% |
16
% |
3
% |
37
% |
6
% |
24% |
3% |
| Burgess |
59
% |
14
% |
71
% |
14
% |
97
% |
17
% |
91% |
14% |
| Butte
& Market Lake |
33
% |
70
% |
42
% |
72
% |
81
% |
93
% |
63% |
73%
|
| Consolidated
Farmers |
53
% |
28
% |
64
% |
29
% |
94
% |
35
% |
86% |
29% |
| Corbett |
1
% |
0
% |
1
% |
0
% |
4
% |
0
% |
1% |
0% |
| Danskin |
0
% |
0
% |
0
% |
0
% |
0
% |
0
% |
0
% |
0
% |
| E.
Labelle |
22
% |
0
% |
22
% |
0
% |
25
% |
0
% |
24% |
0% |
| Egin |
22
% |
3
% |
27
% |
3
% |
54
% |
4
% |
41% |
3% |
| Enterprise
(Falls R) |
35
% |
34
% |
44
% |
34
% |
79
% |
44
% |
64% |
35% |
| Enterprise
(Snake R) |
51
% |
49
% |
62
% |
52
% |
93
% |
61
% |
84% |
51% |
| Falls
Irrg AF |
6
% |
12
% |
8
% |
15
% |
28
% |
41
% |
13% |
16% |
|
Irrigation District
|
January,
2005 |
February,
2005 |
March,
2005 |
April,
2005 |
| Probability
of a Shortage |
Severity |
Probability
of a Shortage |
Severity |
Probability
of a Shortage |
Severity |
Probability
of a Shortage |
Severity |
| Falls
River |
26
% |
9
% |
32
% |
10
% |
61
% |
14
% |
46% |
10% |
| Farmers
Friend (Snake R) |
47
% |
2
% |
53
% |
2
% |
69
% |
2
% |
62% |
2% |
| Farmers
Friend (Teton R) |
70
% |
21
% |
78
% |
21
% |
93
% |
23
% |
89% |
21% |
| Farmers
Own |
84
% |
73
% |
94
% |
74
% |
100
% |
84
% |
100% |
75% |
| Gooding
Res #2 |
20
% |
8
% |
25
% |
7
% |
51
% |
11
% |
37% |
7% |
| Great
Western & Porter |
5
% |
2
% |
7
% |
3
% |
24
% |
13
% |
11% |
3% |
| Harrison |
46
% |
19
% |
57
% |
20
% |
90
% |
24
% |
79% |
20% |
| Idaho |
0
% |
0
% |
0
% |
0
% |
1
% |
0
% |
0% |
0% |
| Independent |
68
% |
50
% |
81
% |
51
% |
100
% |
59
% |
98% |
51% |
| Island |
34
% |
5
% |
41
% |
5
% |
69
% |
6
% |
57% |
5% |
| Island
Ward |
60
% |
40
% |
72
% |
40
% |
96
% |
48
% |
90% |
41% |
| Kennedy |
0
% |
0
% |
0
% |
0
% |
0
% |
0
% |
0% |
0% |
| Lenroot |
43
% |
24
% |
53
% |
25
% |
90
% |
31
% |
77% |
25% |
|
Irrigation District
|
January,
2005 |
February,
2005 |
March,
2005 |
April,
2005 |
| Probability
of a Shortage |
Severity |
Probability
of a Shortage |
Severity |
Probability
of a Shortage |
Severity |
Probability
of a Shortage |
Severity |
| Marysville |
56
% |
57
% |
68
% |
58
% |
95
% |
69
% |
87% |
59% |
| Milner
Low Lift |
8
% |
6
% |
8
% |
7
% |
27
% |
20
% |
12% |
8% |
| Minidoka
N&S |
32
% |
31
% |
40
% |
32
% |
80
% |
42
% |
62% |
32% |
| New
Lava Side |
0
% |
0
% |
0
% |
0
% |
0
% |
0
% |
0% |
0% |
| Osgood |
7
% |
4
% |
8
% |
5
% |
29
% |
14
% |
13% |
6% |
| Parks
& Lewisville |
0
% |
0
% |
0
% |
0
% |
0
% |
0
% |
0% |
0% |
| Peoples |
19
% |
19
% |
24
% |
20
% |
57
% |
29
% |
38% |
20% |
| Reid |
18
% |
1
% |
22
% |
1
% |
46
% |
3
% |
33% |
2% |
| Rexburg |
35
% |
5
% |
43
% |
5
% |
77
% |
6
% |
62% |
5% |
| Rigby |
46
% |
8
% |
56
% |
8
% |
87
% |
10
% |
76% |
8% |
| Riverside |
26
% |
0
% |
26
% |
0
% |
27
% |
0
% |
26% |
0% |
| Rudy |
62
% |
51
% |
74
% |
52
% |
97
% |
61
% |
92% |
53% |
| Salem
Union |
43
% |
31
% |
54
% |
32
% |
90
% |
40
% |
77% |
33% |
|
Irrigation District
|
January,
2005 |
February,
2005 |
March,
2005 |
April,
2005 |
| Probability
of a Shortage |
Severity |
Probability
of a Shortage |
Severity |
Probability
of a Shortage |
Severity |
Probability
of a Shortage |
Severity |
| Snake
River Valley |
34
% |
22
% |
43
% |
22
% |
79
% |
29
% |
63% |
23% |
| St.
Anthony Union |
3
% |
0
% |
3
% |
0
% |
15
% |
1
% |
5% |
0% |
| Sunnydell |
58
% |
23
% |
70
% |
23
% |
98
% |
27
% |
92% |
23% |
| Teton |
32
% |
7
% |
40
% |
7
% |
78
% |
9
% |
61% |
7% |
| Teton
Island |
40
% |
8
% |
50
% |
8
% |
87
% |
10
% |
73% |
8% |
| Texas |
0
% |
0
% |
0
% |
0
% |
1
% |
0
% |
0% |
0% |
| Twin
Falls N |
33
% |
23
% |
42
% |
24
% |
81
% |
31
% |
64% |
24% |
| Twin
Falls S |
35
% |
7
% |
43
% |
7
% |
79
% |
9
% |
63% |
7% |
| Twin
Groves |
56
% |
20
% |
66
% |
21
% |
91
% |
25
% |
83% |
21% |
| W.
Labelle & Long Island |
25
% |
3
% |
31
% |
3
% |
68
% |
4
% |
49% |
3% |
| Watson |
31
% |
0
% |
33
% |
0
% |
39
% |
0
% |
36% |
0% |
| Wilford |
30
% |
2
% |
36
% |
2
% |
60
% |
4
% |
49% |
3% |
| Woodville |
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