Pond Evaporation Calculation 1/31/19
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 2018 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec or Avg.
Ovid Avg. Temp F 26.12 24.25 38.74 43.06 61.94 71.81 73.83 69.99 65.24 45.86 34.64 27.65 48.59
Ref date as of 12/31/2018 Total Precip " 0.37 0.57 0.57 1.96 4.68 4.75 2.84 1.6 1.15 1.53 0.57 0.48 21.07
Site Type: Alfalfa Total Alfalfa ETr " 1.53 1.99 4.72 5.72 7.63 9.89 9.35 7.61 6.38 4.01 2.63 1.94 63.4
Total Growing Degee Days from March 1 0 0 117 162 415 598 700 594 479 210 77 29 3381
Gross Pond Evap Total " 1.29 1.67 3.96 4.8 6.41 8.31 7.85 6.39 5.36 3.37 2.21 1.63 53.25
Net Pond Evap Total " 1.03 1.27 3.57 3.43 3.13 4.98 5.87 5.27 4.55 2.3 1.81 1.29 38.5
Crook Avg. Temp F 28.24 25.6 40.16 44.42 61.39 71.46 74.03 69.33 63.51 45.26 34.78 27.12 48.78
Ref date as of 12/31/2018 Total Precip " 0.38 0.43 0.6 1.45 3.18 2.45 2.73 1.1 2.6 1.28 0.42 0.22 16.84
Site Type: Alfalfa Total Alfalfa ETr " 1.54 1.91 4.54 5.2 6.24 8.52 9.12 7.44 5.84 3.72 2.73 2.02 58.82
Total Growing Degee Days from March 1 0 0 137 171 401 574 688 576 447 209 73 28 3304
Gross Pond Evap Inch 1.29 1.6 3.81 4.37 5.24 7.16 7.66 6.25 4.91 3.12 2.29 1.7 49.4
Net Pond Evap Inch 1.03 1.3 3.39 3.35 3.02 5.44 5.75 5.48 3.09 2.23 2 1.54 37.62
 
Sterling Avg. Temp F 28.83 26.59 41.68 46.14 61.58 71.69 74.45 69.37 64.56 46.22 35.13 27.46 49.48
Ref date as of 12/31/2018 Total Precip " 0.38 0.54 0.29 1.18 4.35 1.23 2.46 1.05 0.4 1.03 0.27 0.13 13.31
Site Type: Alfalfa Total Alfalfa ETr " 1.89 2.27 5.53 6.33 7.22 9.68 9.65 7.34 6.13 3.68 2.47 1.8 63.99
Total Growing Degee Days from March 1 0 0 157 195 401 572 688 578 463 222 77 29 3382
Gross Pond Evap Inch 1.59 1.91 4.65 5.32 6.06 8.13 8.11 6.17 5.15 3.09 2.07 1.51 53.76
Net Pond Evap Inch 1.32 1.53 4.44 4.49 3.02 7.27 6.38 5.43 4.87 2.37 1.89 1.42 44.43
 
Brush Avg. Temp F 28.23 26.78 41.78 46.96 61.37 70.24 73.62 69.01 63.48 46.4 34.56 26.75 49.1
Ref date as of 12/31/2018 Total Precip " 0.36 0.58 0.31 0.71 4.97 1.13 1.99 0.88 0.16 1.26 0.24 0.16 12.75
Site Type: Alfalfa Total Alfalfa ETr " 1.96 2.34 6.31 6.96 6.82 9.06 9.48 7.67 5.95 3.85 2.6 1.94 64.94
Total Growing Degee Days from March 1 0 0 174 217 406 552 673 575 454 229 84 34 3398
Gross Pond Evap Inch 1.65 1.97 5.3 5.85 5.73 7.61 7.96 6.44 5 3.23 2.18 1.63 54.55
Net Pond Evap Inch 1.39 1.56 5.08 5.35 2.25 6.82 6.57 5.83 4.89 2.35 2.02 1.52 45.63
 
Fort Morgan Avg. Temp F 27.4 25.65 40.67 45.98 61.05 71.04 74.16 69.79 64.69 46.9 35.43 27.77 49.21
Ref date as of 12/31/2018 Total Precip " 0.15 0.37 0.28 0.69 4.58 3.58 3.3 0.95 0.19 1 0.14 0.03 15.26
Site Type: Turf Total Alfalfa ETr " 1.57 2.02 5.09 5.99 6.64 8.51 8.47 7.09 5.67 3.31 2.18 1.6 58.14
Total Growing Degee Days from March 1 0 0 146 200 392 568 690 600 469 224 78 29 3396
Gross Pond Evap Inch 1.32 1.7 4.28 5.03 5.58 7.15 7.11 5.96 4.76 2.78 1.83 1.34 48.84
Net Pond Evap Inch 1.21 1.44 4.08 4.55 2.37 4.64 4.8 5.29 4.63 2.08 1.73 1.32 38.14
 
Wiggins Avg. Temp F 27.14 25.94 40.81 46.49 61.19 70.77 72.86 69.74 63.49 46.41 34.56 26.92 48.86
Ref date as of 12/31/2018 Total Precip " 0.28 0.49 0.4 0.63 3.97 2.93 1.51 0.75 0.34 0.45 0.19 0.02 11.96
Site Type: Alfalfa Total Alfalfa ETr " 1.76 2.33 5.71 6.65 7.02 9.41 9.04 8.08 5.88 3.82 2.53 1.92 64.15
Total Growing Degee Days from March 1 0 0 161 207 402 548 655 585 457 230 80 32 3357
Gross Pond Evap Inch 1.48 1.96 4.8 5.59 5.9 7.9 7.59 6.79 4.94 3.21 2.13 1.61 53.9
Net Pond Evap Inch 1.28 1.61 4.52 5.15 3.12 5.85 6.54 6.26 4.7 2.89 1.99 1.6 45.51
 
Fort Collins East Avg. Temp F 30.48 27.34 41.69 46.48 59.46 69.99 71.62 68.07 62.47 46.54 36.05 29.15 49.11
Ref date as of 12/31/2018 Total Precip " 0.28 0.57 0.79 0.77 3.09 1.06 1.16 0.1 0.38 0.62 0.41 0.1 9.33
Site Type: Alfalfa Total Alfalfa ETr " 2.22 2.46 5.5 6.38 6.46 9.59 8.39 7.45 5.99 3.59 2.7 2.19 62.92
Total Growing Degee Days from March 1 0 0 136 199 365 531 626 554 439 210 61 28 3149
Gross Pond Evap Inch 1.86 2.07 4.62 5.36 5.43 8.06 7.05 6.26 5.03 3.02 2.27 1.84 52.87
Net Pond Evap Inch 1.67 1.67 4.07 4.82 3.26 7.31 6.24 6.19 4.77 2.58 1.98 1.77 46.33
 
Eaton Avg. Temp F 29.25 25.95 41.05 46.37 59.96 69.75 70.96 67.77 62.89 46.06 35.11 28.05 48.6
Ref date as of 12/31/2018 Total Precip " 0.4 0.63 0.89 0.77 3.81 1.53 1.11 0.25 0.17 0.61 0.43 0.04 10.64
Site Type: Alfalfa Total Alfalfa ETr " 1.93 2.37 5.4 6.63 6.97 9.11 7.88 6.94 6.02 3.72 2.61 1.93 61.51
Total Growing Degee Days from March 1 0 0 142 212 379 525 622 554 453 212 60 26 3185
Gross Pond Evap Inch 1.62 1.99 4.54 5.57 5.85 7.65 6.62 5.83 5.06 3.12 2.19 1.62 51.66
Net Pond Evap Inch 1.34 1.55 3.91 5.03 3.19 6.58 5.84 5.65 4.94 2.7 1.89 1.59 44.21
 
Johnsons Corner Avg. Temp F 31.79 28.12 42.29 46.95 59.55 70.06 71.69 69.03 63.91 47.23 36.35 30.33 49.78
Ref date as of 12/31/2018 Total Precip " 0.47 0.88 0.98 0.89 3.57 3.73 2.61 0.69 0.14 0.99 0.59 0.16 15.7
Site Type: Alfalfa Total Alfalfa ETr " 2.05 2.37 5.01 5.93 6.04 8.98 7.97 7.42 6.02 3.41 2.39 2.04 59.63
Total Growing Degee Days from March 1 0 0 128 187 350 541 647 587 443 197 51 23 3154
Gross Pond Evap Inch 1.72 1.99 4.21 4.98 5.07 7.54 6.69 6.23 5.06 2.86 2.01 1.71 50.07
Net Pond Evap Inch 1.39 1.37 3.52 4.36 2.57 4.93 4.87 5.75 4.96 2.17 1.59 1.6 39.08
 
Gilcrest Avg. Temp F 28.41 27.22 42.18 47.79 60.56 71.3 72.46 69.79 64.13 46.82 35.89 28.62 49.6
Ref date as of 12/31/2018 Total Precip " 0.45 0.58 0.99 1.01 2.73 4.16 3.35 0.75 1.2 0.99 0.47 0.11 16.79
Site Type: Alfalfa Total Alfalfa ETr " 1.74 2.42 5.16 6.39 6.8 9.79 8.43 7.98 6.24 3.45 2.41 1.92 62.73
Total Growing Degee Days from March 1 0 0 153 222 383 554 659 588 461 221 72 26 3339
Gross Pond Evap Inch 1.46 2.03 4.33 5.37 5.71 8.22 7.08 6.7 5.24 2.9 2.02 1.61 52.67
Net Pond Evap Inch 1.15 1.63 3.64 4.66 3.8 5.31 4.74 6.18 4.4 2.21 1.7 1.54 40.96
 
Longmont South Avg. Temp F 31.68 28.71 41.74 46.87 58.68 69.73 71.19 68.87 63.18 47.15 36.65 30.45 49.58
Ref date as of 12/31/2018 Total Precip " 0.44 0.76 1.57 1.05 4.91 2.35 2.22 1.29 0.65 1.24 0.63 0.21 17.32
Site Type: Alfalfa Total Alfalfa ETr " 2.11 2.58 4.97 5.95 5.9 8.79 7.85 7.36 5.69 3.44 2.56 2.09 59.29
Total Growing Degee Days from March 1 0 0 130 193 342 516 618 568 442 202 67 31 3109
Gross Pond Evap Inch 1.77 2.17 4.17 5 4.96 7.38 6.59 6.18 4.78 2.89 2.15 1.76 49.8
Net Pond Evap Inch 1.46 1.64 3.08 4.26 1.52 5.74 5.04 5.28 4.32 2.02 1.71 1.61 37.68
 
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 31.18 28.58 42.32 47.32 59.72 69.83 71.88 69.01 63.01 46.05 36.22 29.32 49.54
Ref date as of 12/31/2018 Total Precip " 0.25 0.36 0.67 0.76 4.57 1.22 1.89 0.38 0.36 0.77 0.52 0.05 11.8
Site Type: Turf Total Alfalfa ETr " 1.79 2.23 4.59 5.53 5.96 7.99 7.26 6.41 5.16 2.76 2.03 1.57 53.28
Total Growing Degee Days from March 1 0 0 134 201 366 519 623 567 451 205 58 31 3155
Gross Pond Evap Inch 1.5 1.87 3.86 4.65 5.01 6.71 6.1 5.38 4.33 2.32 1.71 1.32 44.76
Net Pond Evap Inch 1.33 1.62 3.39 4.11 1.81 5.86 4.78 5.12 4.08 1.78 1.34 1.28 36.5
 
Windsor 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 7/1/2012 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: Dryland Pasture 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
 
Greeley West Avg. Temp F 29.35 27.04 42.11 47.57 60.85 71.28 73.56 70.52 65.43 47.61 36.44 29.51 50.11
Ref date as of 12/31/2018 Total Precip " 0.47 0.67 1.02 0.79 3.04 2.57 1.47 0.77 0.25 1 0.56 0.14 12.75
Site Type: Turf Total Alfalfa ETr " 1.47 2.12 4.7 5.83 6.5 8.38 7.88 7.13 5.74 3.18 2.15 1.67 56.75
Total Growing Degee Days from March 1 0 0 155 228 396 563 669 603 484 225 65 26 3414
Gross Pond Evap Inch 1.23 1.78 3.95 4.9 5.46 7.04 6.62 5.99 4.82 2.67 1.81 1.4 47.67
Net Pond Evap Inch 0.91 1.31 3.23 4.34 3.33 5.24 5.59 5.45 4.65 1.97 1.41 1.3 38.73
 
Loveland Avg. Temp F 31.18 28.74 42.38 47.7 60.46 70.62 72.9 70.59 65.45 47.67 36.88 30.55 50.43
Ref date as of 12/31/2018 Total Precip " 0.22 0.95 0.87 0.93 3.42 1.27 1.97 0.88 0.15 1.21 0.56 0.09 12.52
Site Type: Turf Total Alfalfa ETr " 1.69 2.24 4.4 5.51 6.07 7.91 7.09 6.43 5.18 2.86 2.01 1.7 53.09
Total Growing Degee Days from March 1 0 0 156 217 391 557 670 626 495 232 63 39 3446
Gross Pond Evap Inch 1.42 1.88 3.7 4.63 5.1 6.64 5.96 5.4 4.35 2.4 1.69 1.43 44.6
Net Pond Evap Inch 1.27 1.22 3.09 3.98 2.7 5.76 4.58 4.79 4.25 1.56 1.3 1.37 35.87
 
Berthoud Avg. Temp F 31.95 28.3 42.35 47.43 60.1 70.57 72.31 69.98 65.13 47.07 36.48 30.24 50.16
Ref date as of 12/31/2018 Total Precip " 0.31 0.84 1.05 0.86 3.76 1.69 2.03 0.78 0.13 0.93 0.52 0.09 12.99
Site Type: Turf Total Alfalfa ETr " 1.82 2.31 4.66 5.65 6.32 8.49 7.7 7.16 5.66 3.03 2.22 1.79 56.81
Total Growing Degee Days from March 1 0 0 128 193 363 553 663 619 472 195 53 22 3261
Gross Pond Evap Inch 1.53 1.94 3.91 4.75 5.31 7.13 6.47 6.01 4.75 2.55 1.86 1.5 47.71
Net Pond Evap Inch 1.31 1.35 3.18 4.14 2.68 5.95 5.05 5.47 4.66 1.89 1.5 1.44 38.62
 
Longmont West Avg. Temp F 32.96 30.13 43.22 48.63 60.67 71.58 73.62 70.52 65.17 47.5 37.35 30.71 51.01
Ref date as of 12/31/2018 Total Precip " 0.22 0.21 1.29 0.89 4.02 0.98 1.81 1.17 0.32 1.25 0.38 0.04 12.58
Site Type: Turf Total Alfalfa ETr " 1.76 2.25 4.36 5.46 6.09 7.77 7.44 6.63 5.04 2.82 1.94 1.47 53.03
Total Growing Degee Days from March 1 0 0 139 202 364 558 667 614 472 207 68 31 3322
Gross Pond Evap Inch 1.48 1.89 3.66 4.59 5.12 6.53 6.25 5.57 4.23 2.37 1.63 1.23 44.55
Net Pond Evap Inch 1.32 1.74 2.76 3.96 2.3 5.84 4.98 4.75 4.01 1.49 1.36 1.21 35.72
 
Fort Lupton Avg. Temp F 32.22 28.66 42.67 48.44 61.29 71.13 71.24 67.8 63.39 48.32 37.91 31.3 50.36
Ref date as of 12/31/2018 Total Precip " 0.44 0.46 0.77 0.97 2.64 2.09 1.51 1.38 0.17 0.96 0.36 0.07 11.82
Site Type: Turf Total Alfalfa ETr " 2.03 2.46 5.17 6.43 7.02 9.27 8.71 7.77 6.35 3.57 2.5 1.99 63.27
Total Growing Degee Days from March 1 0 0 146 222 398 567 617 558 448 217 76 37 3286
Gross Pond Evap Inch 1.71 2.07 4.34 5.4 5.9 7.79 7.32 6.53 5.33 3 2.1 1.67 53.16
Net Pond Evap Inch 1.4 1.74 3.8 4.72 4.05 6.32 6.26 5.56 5.22 2.33 1.85 1.62 44.87
 
Boulder NW Avg. Temp F 35.59 29.71 41.45 47 59.51 69.84 72.13 69.62 64.84 47.05 37.37 32.31 50.54
Ref date as of 12/31/2018 Total Precip " 0.33 0.49 1.57 1.06 4.5 1.75 1.6 0.67 0.66 2.22 0.7 0.15 15.7
Site Type: Turf Total Alfalfa ETr " 2.24 2.3 4.15 5.2 5.79 7.54 7.25 6.67 5.32 2.87 2.39 1.86 53.58
Total Growing Degee Days from March 1 0 0 117 190 355 525 630 583 471 189 60 34 3154
Gross Pond Evap Inch 1.88 1.93 3.49 4.37 4.86 6.33 6.09 5.6 4.47 2.41 2.01 1.56 45
Net Pond Evap Inch 1.65 1.59 2.39 3.63 1.71 5.11 4.97 5.13 4.01 0.86 1.52 1.46 34.03
 
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 38.18 31.76 43.52 48.53 59.81 70.28 71.49 70.3 65.65 48.54 39.95 34.87 51.91
Ref date as of 12/31/2018 Total Precip " 0.15 0.29 1.5 1.09 4.61 1.38 1.37 0.74 1.13 1.83 0.71 0.11 14.91
Site Type: Turf Total Alfalfa ETr " 2.52 2.59 4.6 5.61 5.86 8.08 7.48 7.15 5.56 3.17 2.71 2.14 57.47
Total Growing Degee Days from March 1 0 0 107 179 345 504 609 577 455 184 57 29 3046
Gross Pond Evap Inch 2.12 2.18 3.86 4.71 4.92 6.79 6.28 6.01 4.67 2.66 2.28 1.8 48.28
Net Pond Evap Inch 2.01 1.97 2.81 3.95 1.7 5.82 5.32 5.49 3.88 1.38 1.78 1.72 37.83
Greeley04 Avg. Temp F 28.22 25.93 41.6 46.51 60.52 70.55 71.94 68.73 63.25 46.15 34.5 27.4 48.78
Ref date as of 12/31/2018 Total Precip " 0.04 0.28 0.82 0.69 2.99 1.62 0.44 0.38 0.08 0.49 0.05 0.06 7.94
Site Type: Fully irrigated Total Alfalfa ETr " 2.06 2.49 5.76 7.23 7.1 10.1 8.46 7.3 6.3 3.72 2.57 2.33 65.42
Total Growing Degee Days from March 1 0 0 151 218 393 551 641 571 457 211 59 25 3277
Gross Pond Evap Inch 1.73 2.09 4.84 6.07 5.96 8.48 7.11 6.13 5.29 3.12 2.16 1.96 54.94
Net Pond Evap Inch 1.7 1.9 4.26 5.59 3.87 7.35 6.8 5.87 5.24 2.78 2.12 1.92 49.4