Pond Evaporation Calculation 12/31/12
Weather Station Data provided by Northern Colorado Water Conservancy District
See Weather Station Location Map at:
http://www.northernwater.org/WaterConservation/WeatherandETData.aspx
Notes:
Current month reflects values through "Reference Date".
Pond Evap. calculated per recent Division 1 Water Court decree language: Lower South Platte Home Page
Gross Pond = .84(Alfalfa ETr) Pond Evaporation Reports Main Menu
Net Pond = .84(Alfalfa ETr) - .7(Total Precip)
Alfalfa reference ETr computed by Standard ASCE equation from daily weather data.
Winter pond evap. is a reference for unfrozen ponds.
For Growing Degree Days:
Tmax = 86 F, Tmin = 50 F and Tbase = 50 F
Totals
Weather Station 2011 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec or Avg.
Ovid Avg. Temp F 24.51 24.43 38.28 46.5 54.53 69.24 77.91 74.41 60.9 50.94 36.5 27.09 48.77
Ref date as of 12/31/2011 Total Precip " 0.29 0.58 0.94 2.17 4.29 2.35 3.75 4.22 1.32 1.14 0.74 0.08 21.87
Site Type: Alfalfa Total Alfalfa ETr " 2.28 2.88 4.16 5.52 7.02 10.16 10.14 8.23 5.88 5.02 4.3 2.84 68.43
Total Growing Degee Days from March 1 0 0 105 168 271 542 767 705 426 300 116 29 3429
Gross Pond Evap Total " 1.92 2.42 3.49 4.64 5.9 8.53 8.52 6.91 4.94 4.22 3.61 2.39 57.49
Net Pond Evap Total " 1.71 2.01 2.84 3.12 2.89 6.89 5.89 3.96 4.02 3.42 3.09 2.33 42.17
Crook Avg. Temp F 24.95 25.2 39.49 45.85 53.14 67.64 75.93 73.15 60.05 48.76 35.26 25.42 47.9
Ref date as of 12/31/2011 Total Precip " 0.18 0.58 1.21 1.72 5.44 2.39 2.83 1.67 1.6 1.19 0.46 0.21 19.48
Site Type: Alfalfa Total Alfalfa ETr " 2.27 2.97 4.51 5.51 6.77 9.16 9.5 8.19 5.89 4.66 4.18 2.88 66.49
Total Growing Degee Days from March 1 0 0 125 165 261 506 720 671 418 276 104 31 3277
Gross Pond Evap Inch 1.91 2.49 3.79 4.63 5.69 7.69 7.98 6.88 4.95 3.91 3.51 2.42 55.85
Net Pond Evap Inch 1.78 2.09 2.94 3.42 1.88 6.02 6 5.71 3.83 3.08 3.19 2.27 42.21
 
Sterling Avg. Temp F 24.16 25.78 40.43 46.39 53.29 68.44 76 74.08 61.02 49.21 35.03 25.51 48.28
Ref date as of 12/31/2011 Total Precip " 0.32 0.28 0.77 1.87 6.35 1.88 4.79 3.21 1.24 1.35 0.27 0.23 22.56
Site Type: Alfalfa Total Alfalfa ETr " 1.96 3.04 4.9 5.86 6.63 9.76 9.82 8.72 6.14 4.98 3.84 2.31 67.96
Total Growing Degee Days from March 1 0 0 140 184 261 525 724 692 432 290 111 25 3384
Gross Pond Evap Inch 1.65 2.55 4.12 4.92 5.57 8.2 8.25 7.32 5.16 4.18 3.23 1.94 57.09
Net Pond Evap Inch 1.42 2.36 3.58 3.61 1.12 6.88 4.9 5.08 4.29 3.24 3.04 1.78 41.3
 
Brush Avg. Temp F 23.02 25.98 42.34 47.98 54.3 68.76 75.65 74.59 61.45 49.44 35.09 25.01 48.63
Ref date as of 12/31/2011 Total Precip " 0.42 0.17 0.31 1.36 4.76 0.97 3.91 1.31 1.41 1.73 0.28 0.21 16.84
Site Type: Alfalfa Total Alfalfa ETr " 1.92 2.93 5.78 6.63 6.49 10.17 9.73 8.35 5.72 4.78 3.59 2.16 68.25
Total Growing Degee Days from March 1 0 0 166 199 273 535 724 696 429 280 107 17 3426
Gross Pond Evap Inch 1.61 2.46 4.86 5.57 5.45 8.54 8.17 7.01 4.8 4.02 3.02 1.81 57.32
Net Pond Evap Inch 1.32 2.34 4.64 4.62 2.12 7.86 5.44 6.1 3.82 2.8 2.82 1.67 45.55
 
Fort Morgan Avg. Temp F 24.69 26.96 40.98 46.36 53.07 67.68 74.57 73.54 60.49 48.15 34.22 23.51 47.85
Ref date as of 12/31/2011 Total Precip " 0.63 0.43 0.43 1.58 6.62 1.73 4.3 0.53 1.28 2.11 0.75 0.35 20.74
Site Type: Turf Total Alfalfa ETr " 1.87 2.67 4.47 5.58 6.02 8.39 8.84 7.95 5.11 3.87 2.96 1.85 59.58
Total Growing Degee Days from March 1 0 0 148 178 261 514 702 674 422 265 93 16 3273
Gross Pond Evap Inch 1.57 2.24 3.75 4.69 5.06 7.05 7.43 6.68 4.29 3.25 2.49 1.55 50.05
Net Pond Evap Inch 1.13 1.94 3.45 3.58 0.42 5.84 4.42 6.31 3.4 1.77 1.96 1.31 35.53
 
Wiggins Avg. Temp F 23.6 25.97 41.35 46.79 53.55 68.25 74.27 73.66 60.87 48.5 34.68 23.09 47.88
Ref date as of 12/31/2011 Total Precip " 0.19 0.23 0.3 1.12 3.27 1.14 4.89 1.85 0.7 1.85 0.14 0.12 15.8
Site Type: Alfalfa Total Alfalfa ETr " 2.18 3.14 5.62 6.54 6.97 10.12 9.13 8.61 6.04 4.76 3.51 1.92 68.54
Total Growing Degee Days from March 1 0 0 162 192 265 522 699 680 431 266 102 18 3337
Gross Pond Evap Inch 1.83 2.64 4.72 5.49 5.85 8.5 7.67 7.23 5.07 4 2.95 1.61 57.56
Net Pond Evap Inch 1.7 2.48 4.51 4.71 3.57 7.7 4.25 5.94 4.58 2.7 2.85 1.53 46.52
 
Fort Collins East Avg. Temp F 26.62 26.2 42.23 46.99 52.52 66.58 72.63 71.36 59.94 48.66 36.18 25.16 47.92
Ref date as of 12/31/2011 Total Precip " 0.18 0.49 0.16 1.59 3.73 2.08 2.05 0.52 1.33 1.92 0.34 0.39 14.78
Site Type: Alfalfa Total Alfalfa ETr " 2.54 3.19 5.44 6.32 6.36 8.89 8.45 8.05 5.67 4.59 3.62 2.18 65.3
Total Growing Degee Days from March 1 0 0 140 177 236 486 668 628 398 269 76 18 3096
Gross Pond Evap Inch 2.13 2.68 4.57 5.31 5.34 7.47 7.1 6.76 4.76 3.86 3.04 1.83 54.85
Net Pond Evap Inch 2.01 2.34 4.46 4.2 2.73 6.01 5.66 6.4 3.83 2.51 2.8 1.56 44.51
 
Eaton Avg. Temp F 26.1 26.21 41.5 46.8 52.56 66.94 73.16 72.23 60.84 49.08 35.61 25.23 48.02
Ref date as of 12/31/2011 Total Precip " 0.14 0.36 0.38 1.31 5.1 0.95 1.55 0.37 0.75 2.16 0.46 0.16 13.69
Site Type: Alfalfa Total Alfalfa ETr " 2.28 3.25 5.49 6.6 6.46 9.53 8.87 8.13 5.82 4.5 3.56 1.99 66.48
Total Growing Degee Days from March 1 0 0 145 185 243 495 684 648 415 272 87 21 3195
Gross Pond Evap Inch 1.92 2.73 4.61 5.54 5.43 8.01 7.45 6.83 4.89 3.78 2.99 1.67 55.85
Net Pond Evap Inch 1.82 2.48 4.35 4.63 1.86 7.34 6.37 6.57 4.36 2.27 2.67 1.56 46.28
 
Johnsons Corner Avg. Temp F 27.57 28.11 42.81 47.06 52.62 66.91 73.73 73.04 61.8 50.64 37.48 24.89 48.89
Ref date as of 12/31/2011 Total Precip " 0.33 0.51 0.26 2.04 4.65 0.78 1.15 0.63 0.77 1.26 0.62 0.69 13.69
Site Type: Alfalfa Total Alfalfa ETr " 2.23 2.94 5.33 6.15 6.1 8.79 8.79 8.3 5.68 4.77 3.39 1.61 64.08
Total Growing Degee Days from March 1 0 0 141 175 231 498 693 663 414 269 74 9 3167
Gross Pond Evap Inch 1.87 2.47 4.48 5.17 5.12 7.38 7.38 6.97 4.77 4.01 2.85 1.35 53.82
Net Pond Evap Inch 1.64 2.11 4.3 3.74 1.87 6.84 6.58 6.53 4.23 3.12 2.41 0.87 44.24
 
Gilcrest Avg. Temp F 23.73 25.71 41.64 46.68 52.19 67.13 73.37 73.03 60.84 48.96 35.44 20.26 47.42
Ref date as of 12/31/2011 Total Precip " 0.21 0.3 0.08 1.38 4.47 0.58 1.62 1.07 0.45 1.7 0.58 0.43 12.87
Site Type: Alfalfa Total Alfalfa ETr " 1.92 2.88 5.36 6.22 6.01 9.46 8.69 8.09 5.09 4.12 3.13 1.39 62.36
Total Growing Degee Days from March 1 0 0 150 179 228 508 681 668 425 274 91 8 3212
Gross Pond Evap Inch 1.61 2.42 4.5 5.22 5.05 7.95 7.3 6.8 4.28 3.46 2.63 1.17 52.39
Net Pond Evap Inch 1.47 2.21 4.45 4.26 1.92 7.54 6.17 6.05 3.96 2.27 2.22 0.87 43.39
 
Longmont South Avg. Temp F 29.73 29.39 43.82 48.16 53.42 67.97 73.91 74.16 62.43 51.33 39.46 25.92 49.98
Ref date as of 12/31/2011 Total Precip " 0.35 0.54 0.25 1.94 4.05 0.83 2.33 0.4 1.53 1.41 0.46 0.79 14.88
Site Type: Alfalfa Total Alfalfa ETr " 2.65 3.21 5.8 6.47 6.57 9.31 8.35 8.85 5.5 4.93 4 1.96 67.6
Total Growing Degee Days from March 1 0 0 154 182 237 505 694 675 419 287 95 17 3265
Gross Pond Evap Inch 2.23 2.7 4.87 5.43 5.52 7.82 7.01 7.43 4.62 4.14 3.36 1.65 56.78
Net Pond Evap Inch 1.98 2.32 4.7 4.08 2.68 7.24 5.38 7.15 3.55 3.15 3.04 1.09 46.36
 
Fort Collins NW Avg. Temp F #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A 0
Ref date as of 12/31/2010 Total Precip " #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A 0
Site Type: Turf Total Alfalfa ETr " #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A 0
Total Growing Degee Days from March 1 0 0 #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A 0
Gross Pond Evap Inch #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A 0
Net Pond Evap Inch #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A 0
 
Fort Collins Central Avg. Temp F 27.99 27.41 42.32 46.53 52.05 66.2 73.24 72.47 60.22 49.09 37.13 26.21 48.41
Ref date as of 12/31/2011 Total Precip " 0.32 0.41 0.32 2.11 4.31 2.41 1.56 0.27 2.22 1.48 0.52 0.69 16.62
Site Type: Turf Total Alfalfa ETr " 1.69 2.17 4.37 5.39 5.24 7.71 7.47 7.08 4.93 3.67 2.42 1.33 53.47
Total Growing Degee Days from March 1 0 0 127 154 219 477 673 641 402 271 85 23 3072
Gross Pond Evap Inch 1.42 1.82 3.67 4.53 4.4 6.48 6.27 5.95 4.14 3.08 2.03 1.12 44.91
Net Pond Evap Inch 1.2 1.54 3.45 3.05 1.38 4.79 5.18 5.76 2.59 2.05 1.67 0.63 33.29
 
Windsor Avg. Temp F -63.55 28.01 43.17 47.61 53.39 68.08 74.83 74.8 63.2 51.2 37.71 26.01 51.64
Ref date as of 12/31/2011 Total Precip " 0.05 0.52 0.18 1.85 5.21 1.05 3.18 0.12 1.16 1.74 0.72 0.51 16.29
Site Type: Dryland Pasture Total Alfalfa ETr " 0.76 2.62 5.12 5.98 5.1 6.19 8.85 8.69 5.61 4.41 2.74 1.26 57.33
Total Growing Degee Days from March 1 0 0 149 193 253 522 723 700 437 287 83 9 3356
Gross Pond Evap Inch 0.64 2.2 4.3 5.02 4.28 5.2 7.43 7.3 4.71 3.7 2.3 1.06 48.14
Net Pond Evap Inch 0.6 1.84 4.17 3.73 0.64 4.46 5.21 7.22 3.9 2.49 1.8 0.7 36.76
 
Greeley West Avg. Temp F 25.67 26.52 41.78 46.62 52.58 67.31 74.24 73.45 61.37 49.43 35.17 23.44 48.13
Ref date as of 12/31/2011 Total Precip " 0 0 0 0 0 0 0 0 0 0.99 0.74 0.58 2.31
Site Type: Turf Total Alfalfa ETr " 1.68 2.44 4.74 5.77 5.78 8.79 8.88 7.73 5.4 3.96 2.48 1.23 58.88
Total Growing Degee Days from March 1 0 0 136 172 239 506 703 672 419 286 70 8 3211
Gross Pond Evap Inch 1.41 2.05 3.98 4.85 4.86 7.38 7.46 6.49 4.54 3.33 2.08 1.03 49.46
Net Pond Evap Inch 1.41 2.05 3.98 4.85 4.86 7.38 7.46 6.49 4.54 2.63 1.57 0.63 47.85
 
Loveland Avg. Temp F 27.6 28.15 43.14 46.99 52.87 67.32 74.58 73.93 61.68 50.37 37.95 25.35 49.16
Ref date as of 12/31/2011 Total Precip " 0.46 0.53 0.29 2.1 4.01 1.63 1.79 0.2 1.77 0.97 0.31 0.31 14.37
Site Type: Turf Total Alfalfa ETr " 1.62 2.31 4.54 5.38 5.44 8.1 7.83 7.26 4.84 3.64 2.5 1.25 54.71
Total Growing Degee Days from March 1 0 0 141 170 235 509 706 687 433 294 86 16 3277
Gross Pond Evap Inch 1.36 1.94 3.81 4.52 4.57 6.8 6.58 6.1 4.07 3.06 2.1 1.05 45.96
Net Pond Evap Inch 1.04 1.57 3.61 3.05 1.76 5.66 5.32 5.96 2.83 2.38 1.88 0.83 35.89
 
Berthoud Avg. Temp F 27.13 27.56 42.52 46.94 52.36 67.37 73.9 73.39 62.17 50.64 37.66 25.83 48.96
Ref date as of 12/31/2011 Total Precip " 0.31 0.79 0.15 2.22 4.46 0.85 1.5 1.34 0.87 1.54 0.54 0.65 15.22
Site Type: Turf Total Alfalfa ETr " 1.86 2.69 4.93 5.77 5.73 8.72 8.52 7.74 5.35 4.34 2.96 1.47 60.08
Total Growing Degee Days from March 1 0 0 125 165 218 502 698 681 409 261 67 13 3139
Gross Pond Evap Inch 1.56 2.26 4.14 4.85 4.81 7.32 7.16 6.5 4.49 3.65 2.49 1.23 50.46
Net Pond Evap Inch 1.35 1.71 4.04 3.29 1.69 6.73 6.11 5.56 3.89 2.57 2.11 0.78 39.83
 
Longmont West Avg. Temp F 29.72 30.13 44.87 49.01 54.55 69.84 76.39 75.83 63.52 52.19 40.69 28 51.23
Ref date as of 12/31/2011 Total Precip " 0.32 0.51 0.15 1.99 3.93 0.72 0.9 0.07 1.12 1.26 0.33 0.32 11.62
Site Type: Turf Total Alfalfa ETr " 1.67 2.39 4.64 5.45 5.51 8.04 7.95 7.15 4.56 3.64 2.63 1.31 54.94
Total Growing Degee Days from March 1 0 0 145 182 248 551 741 721 432 287 105 29 3441
Gross Pond Evap Inch 1.4 2.01 3.9 4.58 4.63 6.75 6.68 6.01 3.83 3.06 2.21 1.1 46.16
Net Pond Evap Inch 1.18 1.65 3.79 3.19 1.88 6.25 6.05 5.96 3.05 2.18 1.98 0.88 38.04
 
Fort Lupton Avg. Temp F 28.65 29.67 43.74 48.02 53.65 68.17 74.47 74.45 62.71 51.07 38.64 24.7 49.83
Ref date as of 12/31/2011 Total Precip " 0 0 0 0 0 0 0 0 0 0 0 0.28 0.28
Site Type: Turf Total Alfalfa ETr " 2.1 2.98 5.19 5.86 6.07 9.67 9.53 8.96 5.87 4.65 3.63 1.75 66.26
Total Growing Degee Days from March 1 0 0 157 185 242 518 717 689 428 276 98 16 3326
Gross Pond Evap Inch 1.76 2.5 4.36 4.92 5.1 8.12 8.01 7.53 4.93 3.91 3.05 1.47 55.66
Net Pond Evap Inch 1.76 2.5 4.36 4.92 5.1 8.12 8.01 7.53 4.93 3.91 3.05 1.27 55.46
 
Boulder NW Avg. Temp F 32.67 30.23 43.82 47.31 52.76 68.19 75.15 75.56 62.96 51.84 40.99 28.64 50.84
Ref date as of 12/31/2011 Total Precip " 0.28 0.58 0.43 2.06 4.7 0.95 1.33 0.33 2.02 1.29 0.4 0.78 15.15
Site Type: Turf Total Alfalfa ETr " 2.47 2.51 4.81 5.3 5.56 7.96 7.51 7.48 4.9 4.08 3.16 1.63 57.37
Total Growing Degee Days from March 1 0 0 145 175 242 523 704 697 440 286 95 29 3336
Gross Pond Evap Inch 2.07 2.11 4.04 4.45 4.67 6.69 6.31 6.28 4.12 3.43 2.65 1.37 48.19
Net Pond Evap Inch 1.88 1.7 3.74 3.01 1.38 6.02 5.38 6.05 2.7 2.52 2.37 0.82 37.57
 
Boulder East Avg. Temp F #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A 0
Ref date as of 5/2/2010 Total Precip " #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A 0
Site Type: Turf Total Alfalfa ETr " #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A 0
Total Growing Degee Days from March 1 0 0 #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A 0
Gross Pond Evap Inch #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A 0
Net Pond Evap Inch #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A 0
 
Boulder Flatiron Avg. Temp F #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A 0
Ref date as of 5/2/2010 Total Precip " #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A 0
Site Type: Turf Total Alfalfa ETr " #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A 0
Total Growing Degee Days from March 1 0 0 #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A 0
Gross Pond Evap Inch #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A 0
Net Pond Evap Inch #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A 0
 
Boulder SW Avg. Temp F 33.87 31.39 44.52 47.9 52.92 67.88 74.08 75.33 63.18 53.27 42.85 31.15 51.53
Ref date as of 12/31/2011 Total Precip " 0.16 0.18 0.32 1.85 4.41 1.01 3.02 0.62 2.69 1.09 0.57 0.67 16.59
Site Type: Turf Total Alfalfa ETr " 3.04 2.77 5.01 5.73 5.79 8.31 8.07 8.1 5.1 4.38 3.53 1.91 61.74
Total Growing Degee Days from March 1 0 0 121 145 207 502 692 681 385 259 89 27 3108
Gross Pond Evap Inch 2.55 2.33 4.21 4.81 4.86 6.98 6.78 6.8 4.28 3.68 2.97 1.6 51.85
Net Pond Evap Inch 2.44 2.2 3.98 3.52 1.78 6.27 4.66 6.37 2.4 2.92 2.57 1.14 40.25
Greeley04 Avg. Temp F 24.56 25.69 41.49 46.74 52.89 67.42 73.88 72.27 60.77 48.68 34.46 22.16 47.58
Ref date as of 123111/0/2011 Total Precip " 0.02 0.05 0.2 0.84 3.83 0.8 1.07 0.99 0.86 1.55 0.25 0.05 10.51
Site Type: Fully irrigated Total Alfalfa ETr " 2.05 3.12 5.86 7.2 6.79 10.15 9.27 8.21 5.8 4.58 2.98 1.21 67.22
Total Growing Degee Days from March 1 0 0 155 189 251 512 691 651 427 277 88 7 3248
Gross Pond Evap Inch 1.72 2.62 4.92 6.05 5.7 8.53 7.79 6.9 4.87 3.85 2.5 1.02 56.47
Net Pond Evap Inch 1.71 2.59 4.78 5.46 3.02 7.97 7.04 6.2 4.27 2.76 2.33 0.98 49.11