Pond Evaporation Calculation 1/28/09
Weather Station Data provided by Northern Colorado Water Conservancy District
See Weather Station Location Map at:
http://www.ncwcd.org/ims/ims_weather_form.asp
Notes:
Current month reflects values through "Reference Date".
Pond Evap. calculated per recent Division 1 Water Court decree language:
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 2005 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec or Avg.
Ovid Avg. Temp F 25.6 31.88 38.07 45.69 55.86 67.45 75.36 70.41 65.47 49.37 40.6 27.28 49.42
Ref date as of 12/31/2005 Total Precip " 0.26 0.23 0.98 2.28 2.03 3.27 2.22 2.64 0.08 3.06 0.25 0.18 17.48
Site Type: Alfalfa Total Alfalfa ETr " 2.02 3.04 4.95 5.1 6.99 8.48 10.91 7.81 7.44 4.16 4.38 2.93 68.21
Total Growing Degee Days from March 1 0 0 106 152 308 525 672 609 475 220 154 47 3268
Gross Pond Evap Total " 1.7 2.55 4.16 4.28 5.87 7.12 9.16 6.56 6.25 3.49 3.68 2.46 57.28
Net Pond Evap Total " 1.51 2.39 3.47 2.69 4.45 4.83 7.61 4.71 6.19 1.35 3.5 2.34 45.04
Crook Avg. Temp F 27.15 32.4 38.61 46.69 56.23 67.18 74.57 69.15 63.58 48.67 39.59 26.32 49.18
Ref date as of 12/31/2005 Total Precip " 0.17 0.16 0.84 2.33 3.08 3.74 2.52 2.83 0.08 2.13 0.16 0.14 18.18
Site Type: Alfalfa Total Alfalfa ETr " 2.01 3.02 4.76 5.24 6.42 7.58 9.73 7.22 6.67 3.86 4.35 2.69 63.55
Total Growing Degee Days from March 1 0 0 113 183 311 504 632 581 468 235 159 40 3226
Gross Pond Evap Inch 1.69 2.54 4 4.4 5.39 6.37 8.17 6.06 5.6 3.24 3.65 2.26 53.37
Net Pond Evap Inch 1.57 2.42 3.41 2.77 3.24 3.75 6.41 4.08 5.55 1.75 3.54 2.16 40.65
 
Sterling Avg. Temp F 27.93 32.74 39.1 46.64 56.93 67.8 75.01 69.3 63.1 48.99 39.02 25.91 49.37
Ref date as of 12/31/2005 Total Precip " 0.33 0.2 0.91 2.63 2.41 3.21 1.56 1.48 1.13 2.32 0.46 0.17 16.81
Site Type: Alfalfa Total Alfalfa ETr " 2.06 3.05 5.15 5.6 6.59 8.45 10.12 7.66 6.48 4.44 4.23 2.54 66.37
Total Growing Degee Days from March 1 0 0 122 186 339 509 645 582 468 254 161 37 3303
Gross Pond Evap Inch 1.73 2.56 4.33 4.7 5.54 7.1 8.5 6.43 5.44 3.73 3.55 2.13 55.74
Net Pond Evap Inch 1.5 2.42 3.69 2.86 3.85 4.85 7.41 5.4 4.65 2.11 3.23 2.01 43.98
 
Brush Avg. Temp F 28.47 33.3 39.15 46.55 57.29 67.29 74.81 68.85 64.21 49.33 40.05 26.15 49.62
Ref date as of 12/31/2005 Total Precip " 0.5 0.06 1.02 1.61 0.84 3.18 1.29 1.13 0.3 2.37 0.5 0.11 12.91
Site Type: Alfalfa Total Alfalfa ETr " 1.82 3 5.26 5.61 7.36 8.65 10.4 7.6 6.66 4.14 4.12 2.21 66.83
Total Growing Degee Days from March 1 0 0 131 192 349 505 664 590 478 266 168 34 3377
Gross Pond Evap Inch 1.53 2.52 4.42 4.71 6.18 7.27 8.74 6.38 5.59 3.48 3.46 1.86 56.14
Net Pond Evap Inch 1.18 2.48 3.7 3.59 5.59 5.04 7.83 5.59 5.38 1.82 3.11 1.78 47.09
 
Fort Morgan Avg. Temp F 28.59 33.71 39.3 46.69 57.71 67.17 75.29 69.07 64.28 49.47 39.64 26 49.74
Ref date as of 12/31/2005 Total Precip " 0.27 0.1 1.14 2.08 1.09 5.61 2.08 2.06 0.4 3.52 1.23 0.26 19.84
Site Type: Turf Total Alfalfa ETr " 1.84 2.87 4.91 5.43 7.06 8.07 10.05 7.65 6.43 4 3.73 2.15 64.19
Total Growing Degee Days from March 1 0 0 117 188 345 507 674 587 479 257 155 32 3341
Gross Pond Evap Inch 1.55 2.41 4.12 4.56 5.93 6.78 8.44 6.43 5.4 3.36 3.13 1.81 53.92
Net Pond Evap Inch 1.36 2.34 3.33 3.11 5.17 2.85 6.99 4.98 5.12 0.9 2.27 1.62 40.04
 
Wiggins Avg. Temp F 27.89 32.99 38.91 45.95 57.7 67.49 74.7 67.86 63.7 49.3 39.22 25.35 49.26
Ref date as of 12/31/2005 Total Precip " 0.12 0.19 0.36 1.73 1.55 4.83 1.77 1.21 0.35 2.62 0.55 0.06 15.34
Site Type: Alfalfa Total Alfalfa ETr " 1.7 2.84 5.17 5.73 8.16 9.53 10.34 6.63 6.31 4.12 3.8 2.09 66.42
Total Growing Degee Days from March 1 0 0 144 211 371 509 640 562 474 270 156 33 3370
Gross Pond Evap Inch 1.43 2.39 4.34 4.81 6.85 8.01 8.69 5.57 5.3 3.46 3.19 1.76 55.8
Net Pond Evap Inch 1.34 2.25 4.09 3.6 5.77 4.62 7.45 4.72 5.06 1.63 2.81 1.71 45.05
 
Fort Collins East Avg. Temp F 27.75 32.91 38.71 45.25 54.96 63.8 71.46 66.41 59.97 48.2 38.67 27.45 47.96
Ref date as of 12/31/2005 Total Precip " 0.33 0.28 0.97 2 2.3 3.32 0.15 0.66 0.15 2.74 0.14 0.08 13.12
Site Type: Alfalfa Total Alfalfa ETr " 1.98 3.01 4.9 5.69 6.57 7.67 9.25 7.61 6.04 3.83 4 2.76 63.31
Total Growing Degee Days from March 1 0 0 102 176 295 437 592 526 411 224 123 40 2926
Gross Pond Evap Inch 1.66 2.53 4.12 4.78 5.52 6.44 7.77 6.39 5.07 3.22 3.36 2.32 53.18
Net Pond Evap Inch 1.43 2.33 3.44 3.38 3.91 4.12 7.67 5.93 4.97 1.3 3.26 2.26 44
 
Eaton Avg. Temp F 28.34 33.88 38.93 46.44 56.15 64.78 72.16 66.4 61.24 47.99 38.33 26.54 48.43
Ref date as of 12/31/2005 Total Precip " 0.13 0.09 0.59 1.41 1.41 3.86 0.35 1.9 0.43 3.31 0.36 0.09 13.93
Site Type: Alfalfa Total Alfalfa ETr " 1.98 3.21 4.99 6.27 6.88 7.86 9.39 7.08 6.26 3.58 3.63 2.55 63.68
Total Growing Degee Days from March 1 0 0 109 188 318 453 610 533 433 216 121 39 3020
Gross Pond Evap Inch 1.66 2.7 4.19 5.27 5.78 6.6 7.89 5.95 5.26 3.01 3.05 2.14 53.5
Net Pond Evap Inch 1.57 2.63 3.78 4.28 4.79 3.9 7.64 4.62 4.96 0.69 2.8 2.08 43.74
 
Johnsons Corner Avg. Temp F 29.3 34.87 39.79 45.98 55.73 64.67 73.12 67.13 62.23 49.64 40.2 28.36 49.25
Ref date as of 12/31/2005 Total Precip " 0.46 0.33 0.83 1.92 2.2 3.16 1.2 1.56 0.22 2.9 0.18 0.11 15.07
Site Type: Alfalfa Total Alfalfa ETr " 1.77 2.69 4.6 5.18 6.34 7.7 9.67 7.31 6.22 3.63 3.69 2.6 61.4
Total Growing Degee Days from March 1 0 0 99 169 308 464 632 545 434 219 123 46 3039
Gross Pond Evap Inch 1.49 2.26 3.86 4.35 5.33 6.47 8.12 6.14 5.22 3.05 3.1 2.18 51.57
Net Pond Evap Inch 1.16 2.03 3.28 3.01 3.79 4.26 7.28 5.05 5.07 1.02 2.97 2.11 41.03
 
Gilcrest Avg. Temp F 27.53 33.84 39.33 46.3 56.59 65.52 72.66 67.02 61.24 48.36 38.78 26.61 48.65
Ref date as of 12/31/2005 Total Precip " 0.17 0.11 0.44 1.66 1.3 3.55 1.19 0.72 0.25 2.86 0.39 0.12 12.76
Site Type: Alfalfa Total Alfalfa ETr " 1.55 2.51 4.43 4.78 5.65 7.21 8.75 6.58 5.16 3.05 3.43 2.24 55.34
Total Growing Degee Days from March 1 0 0 112 177 328 477 632 554 441 240 144 46 3151
Gross Pond Evap Inch 1.3 2.11 3.72 4.02 4.75 6.06 7.35 5.53 4.33 2.56 2.88 1.88 46.49
Net Pond Evap Inch 1.18 2.03 3.41 2.85 3.84 3.57 6.52 5.02 4.16 0.56 2.61 1.8 37.55
 
Longmont South Avg. Temp F 31.79 36.39 40.97 47.38 57.21 65.5 74.26 68.57 63.68 50.83 42.68 30.67 50.83
Ref date as of 12/31/2005 Total Precip " 0.85 0.23 1.16 2.15 1.56 2.54 0.52 1.66 0.33 2.41 0.22 0.26 13.89
Site Type: Alfalfa Total Alfalfa ETr " 2.05 2.83 4.59 5.42 6.8 7.86 9.86 7.59 6.22 3.6 4.17 2.89 63.88
Total Growing Degee Days from March 1 0 0 106 189 322 465 646 566 466 243 155 64 3222
Gross Pond Evap Inch 1.72 2.38 3.86 4.55 5.71 6.6 8.28 6.38 5.22 3.02 3.5 2.43 53.65
Net Pond Evap Inch 1.13 2.22 3.04 3.05 4.62 4.82 7.92 5.21 4.99 1.34 3.35 2.25 43.94
 
Fort Collins NW Avg. Temp F 24.89 29.65 34.74 41.59 50.47 59.92 68.36 61.31 55.36 43.44 32.56 24.27 43.88
Ref date as of 12/31/2005 Total Precip " 0.51 0.27 0.47 1.72 2.44 1.82 0.24 0.95 0.1 2.37 0.07 0.15 11.11
Site Type: Turf Total Alfalfa ETr " 0.49 1.01 2.38 2.01 2.79 3.97 9.02 6.21 5.66 3.12 3.26 2.26 42.18
Total Growing Degee Days from March 1 0 0 97 170 300 455 633 541 435 223 115 40 3009
Gross Pond Evap Inch 0.41 0.85 2 1.69 2.34 3.33 7.58 5.22 4.75 2.62 2.74 1.9 35.43
Net Pond Evap Inch 0.05 0.66 1.67 0.48 0.64 2.06 7.41 4.55 4.68 0.96 2.69 1.79 27.64
 
Fort Collins Central Avg. Temp F 30.73 35.32 40.54 47.09 56.83 65.45 74.05 67.84 62.27 49.44 40.35 29.43 49.95
Ref date as of 12/31/2005 Total Precip " 0.58 0.28 0.67 1.73 2.57 2.62 0.19 0.94 0.3 2.91 0.07 0.07 12.93
Site Type: Turf Total Alfalfa ETr " 1.94 2.49 4.2 4.99 6.19 7.18 8.83 6.75 5.63 3.36 3.39 2.32 57.27
Total Growing Degee Days from March 1 0 0 104 179 313 467 638 560 450 250 139 54 3154
Gross Pond Evap Inch 1.63 2.09 3.53 4.19 5.2 6.03 7.42 5.67 4.73 2.82 2.85 1.95 48.11
Net Pond Evap Inch 1.22 1.9 3.06 2.98 3.4 4.2 7.28 5.01 4.52 0.79 2.8 1.9 39.06
 
Windsor Avg. Temp F 26.15 31.68 36.05 41.92 51.76 59.88 68.25 62.43 57.82 45.16 35.31 25.68 45.17
Ref date as of 12/31/2005 Total Precip " 0.57 0.25 0.98 2.24 1.93 3.93 0.87 1.66 0.22 3.51 0.17 0.26 16.59
Site Type: Dryland Pasture Total Alfalfa ETr " 1.94 3.02 5.03 5.98 7.14 7.96 10.41 7.77 6.4 3.66 4.01 2.47 65.79
Total Growing Degee Days from March 1 0 0 132 215 358 508 681 606 488 261 140 50 3439
Gross Pond Evap Inch 1.63 2.54 4.23 5.02 6 6.69 8.74 6.53 5.38 3.07 3.37 2.07 55.27
Net Pond Evap Inch 1.23 2.36 3.54 3.46 4.65 3.94 8.14 5.36 5.22 0.62 3.25 1.89 43.66
 
Greeley West Avg. Temp F 28.73 34.99 40.25 47.31 57.98 66.7 75.43 69.33 64.13 49.96 39.91 27.5 50.19
Ref date as of 12/31/2005 Total Precip " 0.18 0.2 0.43 1.5 1.47 3.64 0.45 0.71 0.22 3.45 0.31 0.08 12.64
Site Type: Turf Total Alfalfa ETr " 1.36 2.42 4.37 5.44 6.93 8.02 9.71 7.25 5.96 3.24 3.06 1.94 59.7
Total Growing Degee Days from March 1 0 0 108 191 342 497 673 593 475 239 129 37 3284
Gross Pond Evap Inch 1.14 2.03 3.67 4.57 5.82 6.74 8.16 6.09 5.01 2.72 2.57 1.63 50.15
Net Pond Evap Inch 1.02 1.89 3.37 3.52 4.79 4.19 7.84 5.59 4.85 0.31 2.35 1.57 41.29
 
Loveland Avg. Temp F 30.12 35.46 40.32 46.93 57.21 65.93 74.84 68.44 63.25 50.01 40.76 29.02 50.19
Ref date as of 12/31/2005 Total Precip " 0.64 0.35 0.48 1.48 1.88 2.38 0.52 1.14 0.36 2.63 0.06 0.13 12.05
Site Type: Turf Total Alfalfa ETr " 1.37 2.08 3.87 4.85 6.17 7.17 8.74 6.37 5.11 2.89 2.7 2.01 53.33
Total Growing Degee Days from March 1 0 0 100 180 328 489 673 584 464 239 124 52 3233
Gross Pond Evap Inch 1.15 1.75 3.25 4.07 5.18 6.02 7.34 5.35 4.29 2.43 2.27 1.69 44.79
Net Pond Evap Inch 0.7 1.5 2.91 3.04 3.87 4.36 6.98 4.55 4.04 0.59 2.23 1.6 36.37
 
Berthoud Avg. Temp F 30.08 35.51 40.12 46.73 56.95 65.48 74.82 68.47 63.86 50.4 41.24 29.16 50.24
Ref date as of 12/31/2005 Total Precip " 0.42 0.18 0.57 1.68 1.83 3.58 1.45 1.85 0.2 3.27 0.08 0.15 15.26
Site Type: Turf Total Alfalfa ETr " 1.77 2.68 4.63 5.34 7.05 7.81 9.57 7.78 6.63 3.8 3.67 2.55 63.28
Total Growing Degee Days from March 1 0 0 98 171 317 475 674 577 458 227 122 45 3164
Gross Pond Evap Inch 1.49 2.25 3.89 4.49 5.92 6.56 8.04 6.54 5.57 3.19 3.08 2.14 53.16
Net Pond Evap Inch 1.19 2.13 3.49 3.31 4.64 4.05 7.02 5.24 5.43 0.9 3.03 2.04 42.47
 
Longmont West Avg. Temp F 31.2 36.52 40.91 47.32 57.88 66.27 75.49 69.34 64.41 50.74 42.27 30.02 51.03
Ref date as of 12/31/2005 Total Precip " 0.66 0.28 0.95 2.21 1.48 2.75 0.72 0.84 0.7 2.25 0.25 0.2 13.29
Site Type: Turf Total Alfalfa ETr " 1.34 2.05 3.51 4.48 6.22 6.77 8.23 6.21 5.09 2.88 2.55 1.74 51.07
Total Growing Degee Days from March 1 0 0 102 176 329 496 695 595 479 240 144 57 3313
Gross Pond Evap Inch 1.13 1.72 2.95 3.76 5.22 5.69 6.91 5.22 4.28 2.42 2.14 1.46 42.9
Net Pond Evap Inch 0.66 1.53 2.28 2.22 4.19 3.76 6.41 4.63 3.79 0.84 1.97 1.32 33.6
 
Fort Lupton 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 12/31/2006 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 NW Avg. Temp F 33.41 35.8 40.1 46.69 57.31 65.85 76.47 70.46 64.99 51.4 43.54 32.38 51.53
Ref date as of 12/31/2005 Total Precip " 1.01 0.28 0.82 2.48 1.89 2.51 0.51 1.54 0.14 2.34 0.3 0.24 14.06
Site Type: Turf Total Alfalfa ETr " 2.32 2.72 4.26 5.03 6.9 7.87 10.2 7.96 6.58 3.8 3.59 2.83 64.06
Total Growing Degee Days from March 1 0 0 98 194 337 491 687 601 497 259 141 56 3361
Gross Pond Evap Inch 1.95 2.28 3.58 4.23 5.8 6.61 8.57 6.69 5.53 3.19 3.02 2.38 53.83
Net Pond Evap Inch 1.24 2.09 3 2.49 4.47 4.85 8.21 5.61 5.43 1.55 2.81 2.21 43.96
 
Boulder East Avg. Temp F 33.32 37.1 41.72 48.34 58.88 67.29 77.82 70.87 66.16 52.15 44.08 32.25 52.5
Ref date as of 12/31/2005 Total Precip " 0.71 0.17 0.69 2.22 1.28 2.44 0.6 1.52 0.18 2.38 0.2 0.2 12.59
Site Type: Turf Total Alfalfa ETr " 1.96 2.6 4.41 5.14 6.86 7.67 9.81 7.35 6.01 3.29 3.44 2.72 61.26
Total Growing Degee Days from March 1 0 0 97 182 334 502 722 609 499 249 155 60 3409
Gross Pond Evap Inch 1.65 2.18 3.7 4.32 5.76 6.44 8.24 6.17 5.05 2.76 2.89 2.28 51.44
Net Pond Evap Inch 1.15 2.07 3.22 2.76 4.87 4.73 7.82 5.11 4.92 1.1 2.75 2.14 42.64
 
Boulder Flatiron Avg. Temp F 31.57 34.9 39.77 46.3 56.48 64.61 72.08 66.84 61.32 49.05 41.4 30.77 49.59
Ref date as of 12/31/2005 Total Precip " 0.71 0.12 0.49 2.19 1.34 2.71 0.58 1.43 0.22 2.82 0.24 0.15 13
Site Type: Turf Total Alfalfa ETr " 1.66 2.15 3.48 4.17 5.48 6.03 6.62 5.01 3.98 2.45 2.77 2.25 46.05
Total Growing Degee Days from March 1 0 0 91 171 310 456 608 537 448 231 145 59 3056
Gross Pond Evap Inch 1.39 1.81 2.92 3.5 4.6 5.07 5.56 4.21 3.34 2.06 2.33 1.89 38.68
Net Pond Evap Inch 0.9 1.72 2.58 1.97 3.67 3.17 5.15 3.21 3.19 0.08 2.16 1.79 29.59
 
Boulder SW Avg. Temp F 35.29 37.53 41.24 47.32 57.5 66.03 75.63 69.34 65.51 52.54 45.71 34.25 52.32
Ref date as of 12/31/2005 Total Precip " 0.95 0.18 0.85 2.69 2.15 2.29 0.35 1.64 0.49 2.85 0.26 0.13 14.83
Site Type: Turf Total Alfalfa ETr " 2.67 2.92 4.64 5.18 6.84 8.24 10.07 7.52 6.8 3.96 4.39 3.35 66.58
Total Growing Degee Days from March 1 0 0 76 151 310 485 699 590 486 230 129 54 3210
Gross Pond Evap Inch 2.24 2.45 3.9 4.35 5.75 6.92 8.46 6.32 5.71 3.33 3.69 2.81 55.93
Net Pond Evap Inch 1.58 2.33 3.3 2.47 4.24 5.32 8.21 5.17 5.37 1.33 3.51 2.72 45.55