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 2007 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec or Avg.
Ovid Avg. Temp F 18.85 26.39 46.23 46.11 59.78 68.15 75.55 74.81 64.74 52.46 38.35 21.23 49.39
Ref date as of 12/31/2007 Total Precip " 0.14 0.15 1.37 5.18 1.98 1.42 2.7 0.99 1.44 0.61 0 0.2 16.18
Site Type: Alfalfa Total Alfalfa ETr " 1.37 1.82 5.58 5.18 7.65 9.5 9.82 9.11 7.62 6.32 4.84 1.49 70.3
Total Growing Degee Days from March 1 0 0 197 175 375 536 720 710 452 283 159 15 3622
Gross Pond Evap Total " 1.15 1.53 4.69 4.35 6.43 7.98 8.25 7.65 6.4 5.31 4.07 1.25 59.06
Net Pond Evap Total " 1.05 1.42 3.73 0.73 5.04 6.99 6.36 6.96 5.39 4.88 4.07 1.11 47.73
Crook Avg. Temp F 17.93 26.6 45.49 45.77 58.99 67.54 74.47 73.6 62.58 50.46 36.33 20.29 48.34
Ref date as of 12/31/2007 Total Precip " 0.12 0.19 1.07 2.52 2.99 1.23 0.19 0.44 0.54 0.36 0 0.04 9.69
Site Type: Alfalfa Total Alfalfa ETr " 1.06 1.65 5.25 4.75 6.8 8.18 8.38 7.74 5.93 5.2 4.46 1.4 60.8
Total Growing Degee Days from March 1 0 0 211 176 355 511 689 677 422 282 165 17 3505
Gross Pond Evap Inch 0.89 1.39 4.41 3.99 5.71 6.87 7.04 6.5 4.98 4.37 3.75 1.18 51.08
Net Pond Evap Inch 0.81 1.25 3.66 2.23 3.62 6.01 6.91 6.19 4.6 4.12 3.75 1.15 44.3
 
Sterling Avg. Temp F 14.76 25.56 45.68 46.44 59.36 68.83 75.68 73.96 63.16 50.57 36.35 19.16 48.29
Ref date as of 12/31/2007 Total Precip " 0.09 0.08 1.21 4.22 2.67 1.49 1.45 1.6 0.62 0.42 0 0 13.85
Site Type: Alfalfa Total Alfalfa ETr " 1.22 1.75 5.63 5.58 7.93 10.18 10.09 8.64 7.1 5.64 4.34 1.46 69.56
Total Growing Degee Days from March 1 0 0 217 193 375 534 708 694 443 295 169 20 3648
Gross Pond Evap Inch 1.02 1.47 4.73 4.69 6.66 8.55 8.48 7.26 5.96 4.74 3.65 1.23 58.44
Net Pond Evap Inch 0.96 1.41 3.88 1.73 4.79 7.51 7.46 6.14 5.53 4.44 3.65 1.23 48.73
 
Brush Avg. Temp F 13.96 25.47 46.25 47.3 59.58 68.37 75.66 74.34 64.42 50.61 37.12 19.05 48.51
Ref date as of 12/31/2007 Total Precip " 0.28 0.09 0.98 2.09 2.64 0.86 3.17 1.24 0.41 0.52 0 0 12.28
Site Type: Alfalfa Total Alfalfa ETr " 1.15 1.53 5.51 5.69 7.87 9.1 9.65 8.19 7.19 5.05 3.64 1.43 66
Total Growing Degee Days from March 1 0 0 210 205 387 532 720 711 475 288 162 21 3711
Gross Pond Evap Inch 0.97 1.29 4.63 4.78 6.61 7.64 8.11 6.88 6.04 4.24 3.06 1.2 55.45
Net Pond Evap Inch 0.77 1.22 3.94 3.32 4.76 7.04 5.89 6.01 5.75 3.88 3.06 1.2 46.84
 
Fort Morgan Avg. Temp F 13.89 24.9 45.51 47.28 59.45 68.83 75.69 73.75 64.03 51.1 37.07 19.37 48.41
Ref date as of 12/31/2007 Total Precip " 0 0 0 0.03 0.1 0.48 2.43 1.74 0.44 0.5 0.06 0.53 6.31
Site Type: Turf Total Alfalfa ETr " 1.07 1.53 5.13 5.61 7.42 9.04 9.43 7.84 6.78 4.97 3.31 1.27 63.4
Total Growing Degee Days from March 1 0 0 198 197 373 537 721 705 467 291 149 18 3656
Gross Pond Evap Inch 0.9 1.29 4.31 4.71 6.23 7.59 7.92 6.59 5.7 4.17 2.78 1.07 53.26
Net Pond Evap Inch 0.9 1.29 4.31 4.69 6.16 7.26 6.22 5.37 5.39 3.82 2.74 0.7 48.85
 
Wiggins Avg. Temp F 12.07 23.43 44.77 46.76 58.83 68.56 75.32 73.32 63.06 50.81 36.8 18.58 47.69
Ref date as of 12/31/2007 Total Precip " 0.34 0.11 0.95 1.56 1.53 1.96 1.35 2.2 0.46 0.49 0.09 0.14 11.18
Site Type: Alfalfa Total Alfalfa ETr " 1.16 1.47 5.26 5.91 7.98 10.14 10.09 8.31 7.09 5.69 3.59 1.38 68.07
Total Growing Degee Days from March 1 0 0 195 200 378 527 704 687 459 293 150 17 3610
Gross Pond Evap Inch 0.97 1.23 4.42 4.96 6.7 8.52 8.48 6.98 5.96 4.78 3.02 1.16 57.18
Net Pond Evap Inch 0.74 1.16 3.75 3.87 5.63 7.15 7.53 5.44 5.63 4.44 2.95 1.06 49.35
 
Fort Collins East Avg. Temp F 18.15 27.99 43.54 45.81 56.32 67.13 72.81 70.3 60.06 49.59 36.88 21.79 47.53
Ref date as of 12/31/2007 Total Precip " 0.11 0.16 1.22 1.62 1.36 0.1 1.41 3.31 1.11 1.5 0.15 0.49 12.54
Site Type: Alfalfa Total Alfalfa ETr " 1.62 2.07 5.27 5.36 6.77 9.15 8.8 7.17 5.54 5.06 3.14 1.72 61.67
Total Growing Degee Days from March 1 0 0 185 170 334 490 650 616 401 257 129 17 3249
Gross Pond Evap Inch 1.36 1.74 4.43 4.5 5.69 7.69 7.39 6.02 4.65 4.25 2.64 1.44 51.8
Net Pond Evap Inch 1.28 1.63 3.57 3.37 4.73 7.62 6.41 3.71 3.88 3.2 2.53 1.1 43.03
 
Eaton Avg. Temp F 17.38 27.61 44.22 46.48 56.84 67.49 72.94 70.11 60.77 48.93 36.28 20.98 47.5
Ref date as of 12/31/2007 Total Precip " 0.09 0.08 1.07 1.27 1.85 0.29 0.26 0.32 0.98 0.47 0.16 0.36 7.2
Site Type: Alfalfa Total Alfalfa ETr " 1.32 1.93 5.4 5.98 6.89 9.46 8.73 6.91 5.74 4.84 3.12 1.45 61.77
Total Growing Degee Days from March 1 0 0 188 185 340 503 666 632 410 256 133 16 3329
Gross Pond Evap Inch 1.11 1.62 4.54 5.02 5.79 7.95 7.33 5.8 4.82 4.07 2.62 1.22 51.89
Net Pond Evap Inch 1.05 1.57 3.79 4.13 4.49 7.74 7.15 5.58 4.14 3.74 2.51 0.97 46.86
 
Johnsons Corner Avg. Temp F 18.96 27.28 45.27 46.28 56.26 67.41 73.87 71.23 61.29 51.45 39.07 23.08 48.45
Ref date as of 12/31/2007 Total Precip " 0.38 0.08 1.11 1.57 0.83 0.35 0.4 3.12 1.12 1.05 0.11 0.51 10.63
Site Type: Alfalfa Total Alfalfa ETr " 1.36 1.79 4.92 5.14 6.48 7.63 9.14 7.9 5.75 5.05 3.07 1.46 59.69
Total Growing Degee Days from March 1 0 0 180 169 341 502 685 649 412 273 140 14 3365
Gross Pond Evap Inch 1.14 1.5 4.13 4.32 5.44 6.41 7.68 6.64 4.83 4.24 2.58 1.23 50.14
Net Pond Evap Inch 0.88 1.45 3.36 3.22 4.86 6.16 7.4 4.45 4.05 3.51 2.5 0.87 42.71
 
Gilcrest Avg. Temp F 12.44 23.9 44.27 46.68 57.09 68.07 73.81 71.23 61.95 49.81 36.33 18.94 47.04
Ref date as of 12/31/2007 Total Precip " 0.29 0.06 0.89 1.64 1.67 0.52 1.36 2.26 1.32 0.66 0.13 0.42 11.22
Site Type: Alfalfa Total Alfalfa ETr " 0.87 1.18 4.16 4.89 5.99 8.59 8.23 7.02 5.75 4.61 2.76 1.33 55.38
Total Growing Degee Days from March 1 0 0 184 186 343 512 678 655 439 284 137 16 3434
Gross Pond Evap Inch 0.73 0.99 3.49 4.11 5.03 7.22 6.91 5.9 4.83 3.87 2.32 1.12 46.52
Net Pond Evap Inch 0.53 0.95 2.87 2.96 3.86 6.85 5.96 4.31 3.91 3.41 2.23 0.82 38.66
 
Longmont South Avg. Temp F 21.48 29.34 45.88 46.76 57.07 67.63 73.97 71.75 62.98 51.87 40.53 25.07 49.53
Ref date as of 12/31/2007 Total Precip " 0.26 0.25 1.14 1.3 0.77 0.47 0.6 1.33 2.06 1.31 0.15 0.35 9.99
Site Type: Alfalfa Total Alfalfa ETr " 1.74 2.2 5 5.28 6.29 8.4 8.86 7.89 6.63 4.98 3.68 1.9 62.85
Total Growing Degee Days from March 1 0 0 194 175 336 497 671 644 440 277 158 23 3415
Gross Pond Evap Inch 1.46 1.85 4.2 4.44 5.28 7.06 7.44 6.63 5.57 4.18 3.09 1.6 52.8
Net Pond Evap Inch 1.28 1.67 3.4 3.53 4.74 6.73 7.02 5.7 4.13 3.27 2.99 1.35 45.81
 
Fort Collins NW Avg. Temp F 14.99 26.29 38.6 41.41 49.23 59.94 67.27 63.54 54.93 42.92 31.16 20.6 42.57
Ref date as of 12/31/2007 Total Precip " 0.22 0.13 1.22 0.6 0.91 0.39 0.58 1.81 0.74 1.74 0.33 0.67 9.34
Site Type: Turf Total Alfalfa ETr " 1.28 1.95 3.38 3.91 5.73 8.04 8.31 6.76 5.28 4.06 2.35 1.44 52.49
Total Growing Degee Days from March 1 0 0 222 197 329 495 669 624 409 252 125 19 3341
Gross Pond Evap Inch 1.08 1.64 2.84 3.28 4.81 6.75 6.98 5.68 4.44 3.41 1.97 1.21 44.09
Net Pond Evap Inch 0.92 1.55 1.99 2.86 4.18 6.48 6.57 4.41 3.92 2.19 1.74 0.74 37.55
 
Fort Collins Central Avg. Temp F 21.52 30.04 45.29 47.21 57.41 67.59 74.44 71.41 61.91 50.36 38.68 25.15 49.25
Ref date as of 12/31/2007 Total Precip " 0.29 0.21 1.34 0.87 1.2 0.45 0.49 3.85 1.46 1.68 0.17 0.66 12.67
Site Type: Turf Total Alfalfa ETr " 1.45 2.04 4.57 4.8 6.05 7.76 8.15 6.64 5.49 4.36 2.88 1.76 55.95
Total Growing Degee Days from March 1 0 0 194 174 342 501 691 650 440 290 156 25 3463
Gross Pond Evap Inch 1.22 1.71 3.84 4.03 5.08 6.52 6.85 5.58 4.61 3.66 2.42 1.48 47
Net Pond Evap Inch 1.02 1.57 2.9 3.42 4.24 6.2 6.5 2.88 3.59 2.49 2.3 1.02 38.13
 
Windsor Avg. Temp F 15.74 25.83 41.23 42.91 51.45 62.11 68.9 66.3 56.49 45.14 34.02 20.03 44.18
Ref date as of 12/31/2007 Total Precip " 0.73 0.21 1.64 1.36 0.9 0.07 1.05 1.93 1.6 1.01 0.26 1.03 11.79
Site Type: Dryland Pasture Total Alfalfa ETr " 1.09 1.69 4.85 5.28 6.55 8.87 9.21 7.82 6.01 4.58 3.03 1.32 60.3
Total Growing Degee Days from March 1 0 0 198 199 377 537 713 684 452 290 150 21 3621
Gross Pond Evap Inch 0.92 1.42 4.07 4.44 5.5 7.45 7.74 6.57 5.05 3.85 2.55 1.11 50.67
Net Pond Evap Inch 0.4 1.27 2.93 3.48 4.87 7.4 7 5.22 3.93 3.14 2.36 0.39 42.39
 
Greeley West Avg. Temp F 17.46 26.93 45.09 47.31 58.48 68.98 75.75 72.72 62.96 50.88 37.97 21.52 48.84
Ref date as of 12/31/2007 Total Precip " 0.34 0.08 1.16 1.63 1.08 0.61 0.94 2.54 1.24 0.57 0.18 0.66 11.03
Site Type: Turf Total Alfalfa ETr " 0.97 1.53 4.34 5.22 6.61 8.63 8.84 7.33 5.72 4.43 2.49 1.18 57.29
Total Growing Degee Days from March 1 0 0 185 191 362 529 715 690 445 282 140 18 3557
Gross Pond Evap Inch 0.81 1.29 3.65 4.38 5.55 7.25 7.43 6.16 4.8 3.72 2.09 0.99 48.12
Net Pond Evap Inch 0.58 1.23 2.83 3.24 4.8 6.82 6.77 4.38 3.94 3.32 1.97 0.53 40.41
 
Loveland Avg. Temp F 20.63 29.51 45.24 46.91 57.48 67.73 74.75 72.24 62.58 51.08 39.15 24 49.28
Ref date as of 12/31/2007 Total Precip " 0.47 0.26 1.3 1.42 1.26 0.21 0.83 1.21 1.35 1.39 0.13 0.67 10.5
Site Type: Turf Total Alfalfa ETr " 1.17 1.81 4.07 4.6 5.95 7.59 8.08 6.77 5.47 3.99 2.43 1.42 53.35
Total Growing Degee Days from March 1 0 0 179 168 344 512 709 679 447 274 141 13 3466
Gross Pond Evap Inch 0.98 1.52 3.42 3.86 5 6.38 6.79 5.69 4.59 3.35 2.04 1.19 44.81
Net Pond Evap Inch 0.65 1.34 2.51 2.87 4.12 6.23 6.21 4.84 3.65 2.38 1.95 0.72 37.47
 
Berthoud Avg. Temp F 20.83 28.14 45.41 46.32 57.14 67.71 74.69 72.08 62.68 51.69 39.33 23.43 49.12
Ref date as of 12/31/2007 Total Precip " 0.29 0.1 1.79 2.13 1.56 0.18 1.02 3.03 1.27 1.22 0.08 0.59 13.26
Site Type: Turf Total Alfalfa ETr " 1.54 1.96 5 5.12 7.03 9.1 9.63 8.35 6.54 5.08 3.19 1.44 63.98
Total Growing Degee Days from March 1 0 0 175 162 331 507 711 672 434 263 128 15 3398
Gross Pond Evap Inch 1.29 1.65 4.2 4.3 5.91 7.64 8.09 7.01 5.49 4.27 2.68 1.21 53.74
Net Pond Evap Inch 1.09 1.58 2.95 2.81 4.81 7.52 7.38 4.89 4.6 3.41 2.62 0.8 44.46
 
Longmont West Avg. Temp F 22.48 30.35 45.96 47.35 58.05 68.76 75.58 73.28 63.46 52.46 40.91 25.58 50.35
Ref date as of 12/31/2007 Total Precip " 0.41 0.39 1.44 1.49 1.23 0.26 0.32 1.43 1.48 1.22 0.17 0.67 10.51
Site Type: Turf Total Alfalfa ETr " 1.29 1.97 3.91 4.55 6.03 7.5 7.97 6.87 4.94 3.72 2.37 1.42 52.54
Total Growing Degee Days from March 1 0 0 184 174 344 533 727 700 453 279 157 25 3576
Gross Pond Evap Inch 1.08 1.65 3.28 3.82 5.07 6.3 6.69 5.77 4.15 3.12 1.99 1.19 44.11
Net Pond Evap Inch 0.8 1.38 2.28 2.78 4.2 6.12 6.47 4.77 3.11 2.27 1.87 0.72 36.77
 
Fort Lupton Avg. Temp F 17.93 26.66 45.18 46.68 57.58 68.18 74.86 72.18 63.21 52.77 40.51 24.98 49.23
Ref date as of 12/31/2007 Total Precip " 0.2 0.08 0.66 1.28 1.26 1.12 0.83 2.69 0.48 0.72 0.15 0.33 9.8
Site Type: Turf Total Alfalfa ETr " 1.61 2.05 5.23 5.92 7.56 9.89 10.2 8.53 7.18 5.59 3.73 2.03 69.52
Total Growing Degee Days from March 1 0 0 191 195 351 521 700 680 460 302 160 21 3581
Gross Pond Evap Inch 1.35 1.72 4.39 4.97 6.35 8.31 8.57 7.17 6.03 4.7 3.13 1.71 58.4
Net Pond Evap Inch 1.21 1.67 3.93 4.08 5.47 7.52 7.99 5.28 5.7 4.19 3.03 1.47 51.54
 
Boulder NW Avg. Temp F 25.02 33.17 46.68 46.9 57.9 68.54 75.52 73.37 63.19 52.85 42.74 28.52 51.2
Ref date as of 12/31/2007 Total Precip " 0.54 0.32 1.66 1.14 1.17 0.42 0.64 1.14 1.16 0.97 0.24 0.96 10.36
Site Type: Turf Total Alfalfa ETr " 1.73 2.62 4.88 5.01 6.64 8.42 9.29 8.03 6.01 4.83 3.58 2.06 63.1
Total Growing Degee Days from March 1 0 0 196 182 357 517 709 685 459 296 166 23 3590
Gross Pond Evap Inch 1.45 2.2 4.1 4.21 5.58 7.07 7.8 6.75 5.05 4.06 3.01 1.73 53.01
Net Pond Evap Inch 1.08 1.98 2.94 3.41 4.76 6.78 7.36 5.95 4.24 3.38 2.84 1.06 45.78
 
Boulder East Avg. Temp F 24.11 32.74 47.37 48.1 59.1 69.99 76.88 74.96 65.03 53.82 42.61 27.87 51.88
Ref date as of 12/31/2007 Total Precip " 0.44 0.22 1.36 1.55 1.27 4.63 0.39 1.28 2.51 1.32 0.16 0.9 16.03
Site Type: Turf Total Alfalfa ETr " 1.52 2.45 4.56 5.16 6.35 8.16 8.85 7.59 5.89 4.47 2.98 2 59.98
Total Growing Degee Days from March 1 0 0 192 177 337 532 733 711 473 285 167 28 3635
Gross Pond Evap Inch 1.28 2.06 3.83 4.33 5.33 6.85 7.43 6.38 4.95 3.75 2.5 1.68 50.37
Net Pond Evap Inch 0.97 1.9 2.88 3.25 4.45 3.61 7.16 5.48 3.19 2.83 2.39 1.05 39.16
 
Boulder Flatiron Avg. Temp F 22 31.59 45.17 46.33 56.48 66.29 72.93 71.24 61.29 50.67 40.03 26.6 49.22
Ref date as of 12/31/2007 Total Precip " 0.4 0.1 1.43 2.03 1.43 0.49 0.64 1.37 1.91 1.31 0.14 0.75 12
Site Type: Turf Total Alfalfa ETr " 1.5 2.28 4.16 4.52 5.45 6.51 6.71 5.68 4.25 3.23 2.26 1.72 48.27
Total Growing Degee Days from March 1 0 0 186 167 321 471 643 638 426 265 151 26 3294
Gross Pond Evap Inch 1.26 1.92 3.49 3.8 4.58 5.47 5.64 4.77 3.57 2.71 1.9 1.44 40.55
Net Pond Evap Inch 0.98 1.85 2.49 2.38 3.58 5.13 5.19 3.81 2.23 1.8 1.8 0.92 32.16
 
Boulder SW Avg. Temp F 27.47 33.91 47.31 46.99 57.64 68.08 74.36 72.92 64.25 54.46 45.09 30.81 51.94
Ref date as of 12/31/2007 Total Precip " 0.72 0.22 1.6 2.86 1.74 0.43 0.6 2.72 1.7 1.43 0.23 0.74 14.99
Site Type: Turf Total Alfalfa ETr " 2.31 2.92 4.94 4.98 6.32 8.3 8.59 7.36 6.37 5.18 4.14 2.73 64.14
Total Growing Degee Days from March 1 0 0 166 154 312 512 675 666 453 256 160 26 3380
Gross Pond Evap Inch 1.94 2.45 4.15 4.18 5.31 6.97 7.22 6.18 5.35 4.35 3.48 2.29 53.87
Net Pond Evap Inch 1.44 2.3 3.03 2.18 4.09 6.67 6.8 4.28 4.16 3.35 3.32 1.78 43.4