Pond Evaporation Calculation 1/31/18
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 2017 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec or Avg.
Ovid Avg. Temp F 24.74 35.89 44.14 49.82 56.64 70.45 76.36 68.74 62.82 48.21 39.41 25.6 50.24
Ref date as of 12/31/2017 Total Precip " 0.61 0.19 1.8 2.34 3.01 0.89 1.31 2.61 1.2 0.76 0.23 0.49 15.44
Site Type: Alfalfa Total Alfalfa ETr " 1.73 3.39 5.4 5.98 7.07 10.32 10.08 7.13 5.55 4.63 2.8 2.22 66.3
Total Growing Degee Days from March 1 0 0 195 211 313 559 721 573 422 246 149 43 3432
Gross Pond Evap Total " 1.45 2.85 4.54 5.02 5.94 8.67 8.47 5.99 4.66 3.89 2.35 1.86 55.69
Net Pond Evap Total " 1.03 2.71 3.28 3.39 3.83 8.05 7.55 4.16 3.82 3.36 2.19 1.52 44.89
Crook Avg. Temp F 25.49 36.18 44.7 49.53 56.05 69.04 75.44 69.01 62.26 48.74 40.37 26.55 50.28
Ref date as of 12/31/2017 Total Precip " 0.56 0.18 1.16 2.47 3.44 2.54 1.55 1.64 1.26 0.96 0.27 0.29 16.32
Site Type: Alfalfa Total Alfalfa ETr " 1.83 3.53 5.63 5.84 6.5 9.16 9.73 6.7 4.56 4.1 2.43 1.93 61.94
Total Growing Degee Days from March 1 0 0 214 212 311 537 700 568 414 258 165 47 3426
Gross Pond Evap Inch 1.54 2.97 4.73 4.91 5.46 7.69 8.17 5.63 3.83 3.44 2.04 1.62 52.03
Net Pond Evap Inch 1.15 2.84 3.92 3.18 3.05 5.92 7.09 4.48 2.95 2.77 1.85 1.42 40.62
 
Sterling Avg. Temp F 25.02 35.83 45.52 50.02 56.33 69.78 75.74 69.55 63.43 48.85 40.92 27.15 50.68
Ref date as of 12/31/2017 Total Precip " 0.48 0.39 1.55 2.09 4.09 1.48 2.56 1.88 0.96 0.82 0.28 0.16 16.74
Site Type: Alfalfa Total Alfalfa ETr " 1.63 3.1 5.36 5.84 6.46 9.17 9.77 7.51 5.61 4.47 2.86 2.13 63.91
Total Growing Degee Days from March 1 0 0 220 216 318 541 716 585 421 256 174 58 3505
Gross Pond Evap Inch 1.37 2.6 4.5 4.91 5.43 7.7 8.21 6.31 4.71 3.75 2.4 1.79 53.68
Net Pond Evap Inch 1.03 2.33 3.42 3.44 2.56 6.67 6.41 4.99 4.04 3.18 2.21 1.68 41.96
 
Brush Avg. Temp F 24.61 35.68 45.07 49.29 55.61 68.79 74.6 69.5 62.09 48.01 40.42 26.58 50.02
Ref date as of 12/31/2017 Total Precip " 0.5 0.35 1.57 2.34 2.8 0.56 0.74 2.43 0.68 0.72 0.22 0.3 13.21
Site Type: Alfalfa Total Alfalfa ETr " 1.69 3.24 5.51 6.02 6.56 9.1 9.3 7.62 5.41 4.74 2.85 2.31 64.35
Total Growing Degee Days from March 1 0 0 228 229 327 537 691 587 422 278 190 66 3555
Gross Pond Evap Inch 1.42 2.72 4.63 5.06 5.51 7.64 7.81 6.4 4.54 3.98 2.39 1.94 54.04
Net Pond Evap Inch 1.07 2.48 3.53 3.42 3.55 7.25 7.29 4.7 4.07 3.48 2.24 1.73 44.81
 
Fort Morgan Avg. Temp F 25.66 36.58 45.8 50.03 56.67 68.68 74.04 68.56 61.66 46.72 39.58 25.91 49.99
Ref date as of 12/31/2017 Total Precip " 0.29 0.27 1.16 3.07 4.31 0.47 0.98 1.39 0.74 0.65 0.15 0.14 13.62
Site Type: Turf Total Alfalfa ETr " 1.56 2.8 4.78 5.66 6.52 8.44 8.7 7.14 5.41 3.87 2.27 1.75 58.9
Total Growing Degee Days from March 1 0 0 227 236 331 527 689 575 408 244 158 47 3442
Gross Pond Evap Inch 1.31 2.35 4.02 4.75 5.48 7.09 7.31 6 4.54 3.25 1.91 1.47 49.48
Net Pond Evap Inch 1.11 2.16 3.2 2.61 2.46 6.76 6.62 5.02 4.03 2.8 1.8 1.37 39.94
 
Wiggins Avg. Temp F 25.24 35.73 44.9 48.7 55.51 68.85 73.83 68.56 61.24 46.94 39.5 26.38 49.62
Ref date as of 12/31/2017 Total Precip " 0.32 0.19 1.11 1.79 3.13 1.51 1.23 1.2 0.83 0.63 0.19 0.14 12.27
Site Type: Alfalfa Total Alfalfa ETr " 1.68 3.14 5.23 6.11 6.54 9.05 8.78 7.54 5.44 4.33 2.61 2.09 62.54
Total Growing Degee Days from March 1 0 0 222 226 323 530 680 580 405 251 175 51 3443
Gross Pond Evap Inch 1.41 2.64 4.39 5.13 5.49 7.6 7.38 6.33 4.57 3.64 2.19 1.76 52.53
Net Pond Evap Inch 1.19 2.5 3.62 3.88 3.3 6.55 6.51 5.49 3.99 3.2 2.06 1.66 43.95
 
Fort Collins East Avg. Temp F 27.87 38.56 45.96 48.88 55.02 67.92 72.54 66.35 59.58 46.67 41.36 30.63 50.11
Ref date as of 12/31/2017 Total Precip " 0.89 0.29 1.02 1.97 4.2 0.15 0.54 3.14 1.78 1.32 0.48 0.15 15.93
Site Type: Alfalfa Total Alfalfa ETr " 2.09 3.84 5.71 6.28 6.71 8.94 8.28 6.17 4.94 3.89 2.86 2.35 62.06
Total Growing Degee Days from March 1 0 0 200 206 311 501 648 524 379 231 142 64 3206
Gross Pond Evap Inch 1.76 3.23 4.8 5.28 5.64 7.51 6.96 5.18 4.15 3.27 2.4 1.97 52.15
Net Pond Evap Inch 1.13 3.02 4.08 3.9 2.7 7.4 6.58 2.98 2.9 2.34 2.07 1.87 40.97
 
Eaton Avg. Temp F 26.42 37.36 45.3 48.54 54.84 68.17 72.56 66.46 60.25 46.35 40.45 28.82 49.63
Ref date as of 12/31/2017 Total Precip " 0.73 0.32 1.01 2.57 6.01 0.36 0.75 2.8 1.26 1.13 0.39 0.22 17.55
Site Type: Alfalfa Total Alfalfa ETr " 1.83 3.55 5.35 6.3 6.8 9.02 8.01 5.99 5.13 4.07 2.64 2.16 60.85
Total Growing Degee Days from March 1 0 0 210 219 314 505 639 534 395 239 145 63 3263
Gross Pond Evap Inch 1.54 2.98 4.49 5.29 5.71 7.58 6.73 5.03 4.31 3.42 2.22 1.81 51.11
Net Pond Evap Inch 1.03 2.76 3.79 3.49 1.51 7.32 6.2 3.07 3.43 2.63 1.94 1.66 38.83
 
Johnsons Corner Avg. Temp F 28.85 39.49 47.21 48.27 54.91 68.7 73.33 67.4 61.25 48.46 43.25 31.3 51.04
Ref date as of 12/31/2017 Total Precip " 0.8 0.4 0.77 1.95 3.82 0.62 1.23 1.27 1.61 1.56 0.66 0.35 15.04
Site Type: Alfalfa Total Alfalfa ETr " 2.05 3.67 5.41 5.94 6.26 8.74 8.19 6.45 5.23 4.06 3.14 2.22 61.36
Total Growing Degee Days from March 1 0 0 201 196 293 526 679 554 390 233 138 62 3272
Gross Pond Evap Inch 1.72 3.08 4.54 4.99 5.26 7.34 6.88 5.42 4.39 3.41 2.64 1.86 51.53
Net Pond Evap Inch 1.16 2.8 4.01 3.62 2.58 6.91 6.02 4.53 3.27 2.32 2.18 1.62 41.02
 
Gilcrest Avg. Temp F 25.08 36.73 44.79 47.88 54.15 67.65 72.06 66.4 59.78 45.33 40.97 28.15 49.08
Ref date as of 12/31/2017 Total Precip " 0.57 0.3 0.77 2.08 5.34 0.68 0.92 1.81 1.65 1.68 0.67 0.32 16.79
Site Type: Alfalfa Total Alfalfa ETr " 1.71 3.38 5.19 6.02 6.02 8.13 7.6 6.26 4.89 3.59 2.67 1.98 57.44
Total Growing Degee Days from March 1 0 0 206 206 294 503 639 534 382 219 153 65 3201
Gross Pond Evap Inch 1.44 2.84 4.36 5.06 5.06 6.83 6.38 5.26 4.11 3.02 2.24 1.66 48.26
Net Pond Evap Inch 1.04 2.63 3.82 3.6 1.32 6.35 5.74 3.99 2.95 1.84 1.77 1.44 36.49
 
Longmont South Avg. Temp F 29.53 40.74 47.94 48.73 54.41 67.98 72.62 67.32 61.12 47.84 43.14 30.35 50.98
Ref date as of 12/31/2017 Total Precip " 1.01 0.34 0.98 1.69 4.89 0.16 0.3 1.46 1.7 1.95 0.58 0.4 15.46
Site Type: Alfalfa Total Alfalfa ETr " 2.14 3.95 5.86 5.79 6.23 8.89 8.45 6.72 5.24 4.08 3.18 2.12 62.65
Total Growing Degee Days from March 1 0 0 211 204 290 496 641 524 379 242 157 69 3213
Gross Pond Evap Inch 1.8 3.32 4.92 4.86 5.23 7.47 7.1 5.64 4.4 3.43 2.67 1.78 52.62
Net Pond Evap Inch 1.09 3.08 4.24 3.68 1.81 7.36 6.89 4.62 3.21 2.06 2.27 1.5 41.81
 
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 28.7 38.76 46.48 49.39 55.21 68.2 73.06 66.98 60.38 46.71 41.66 31.34 50.57
Ref date as of 12/31/2017 Total Precip " 0.59 0.41 0.92 1.9 3.97 0.18 1.23 2.04 2.15 1.73 0.69 0.12 15.93
Site Type: Turf Total Alfalfa ETr " 1.77 2.94 4.5 5.43 6.06 7.6 7.34 5.6 4.49 3.42 2.35 1.87 53.37
Total Growing Degee Days from March 1 0 0 202 213 315 505 648 532 386 235 153 72 3261
Gross Pond Evap Inch 1.49 2.47 3.78 4.56 5.09 6.38 6.17 4.7 3.77 2.87 1.97 1.57 44.82
Net Pond Evap Inch 1.07 2.18 3.14 3.23 2.31 6.26 5.3 3.28 2.27 1.66 1.49 1.49 33.68
 
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 26.97 38.18 46.13 49.27 55.54 69.17 74.45 68.32 62.45 47.37 41.44 29.2 50.71
Ref date as of 12/31/2017 Total Precip " 0.62 0.51 0.78 2.27 8.02 0.58 0.29 2.18 1.34 1.66 0.54 0.39 19.18
Site Type: Turf Total Alfalfa ETr " 1.6 2.97 4.66 5.73 6.31 8.09 7.92 5.95 4.93 3.6 2.31 1.72 55.79
Total Growing Degee Days from March 1 0 0 214 233 324 537 692 581 421 242 149 64 3457
Gross Pond Evap Inch 1.34 2.49 3.91 4.81 5.3 6.8 6.65 5 4.14 3.02 1.94 1.44 46.84
Net Pond Evap Inch 0.91 2.14 3.37 3.22 0 6.39 6.45 3.47 3.2 1.86 1.56 1.17 33.74
 
Loveland Avg. Temp F 29.19 40.54 47.65 49.22 56.05 69 73.88 68.03 61.81 47.62 42.25 31.31 51.38
Ref date as of 12/31/2017 Total Precip " 0.66 0.58 1.07 2.02 3.35 0.41 0.71 2.06 1.82 1.29 1.67 0.13 15.77
Site Type: Turf Total Alfalfa ETr " 1.73 3.23 4.68 5.26 6.02 7.57 7.23 5.75 4.61 3.35 2.32 1.79 53.54
Total Growing Degee Days from March 1 0 0 238 249 336 545 690 578 423 256 156 79 3550
Gross Pond Evap Inch 1.45 2.71 3.93 4.42 5.06 6.36 6.07 4.83 3.87 2.81 1.95 1.5 44.96
Net Pond Evap Inch 0.99 2.31 3.18 3 2.71 6.07 5.58 3.39 2.6 1.91 0.78 1.41 33.93
 
Berthoud Avg. Temp F 29.06 39.51 47.33 49.03 55.6 69.24 74.05 68.29 62.17 48.35 43.42 31.2 51.44
Ref date as of 12/31/2017 Total Precip " 0.89 0.36 0.65 1.67 4.07 0.61 0.87 1.96 1.49 1.6 0.61 0.3 15.08
Site Type: Turf Total Alfalfa ETr " 1.97 3.33 5.03 5.77 6.3 8.44 7.96 6.23 5.01 3.56 2.82 1.91 58.33
Total Growing Degee Days from March 1 0 0 206 216 316 546 695 578 408 235 131 57 3388
Gross Pond Evap Inch 1.65 2.8 4.23 4.85 5.29 7.09 6.69 5.23 4.21 2.99 2.37 1.6 49
Net Pond Evap Inch 1.03 2.55 3.77 3.68 2.44 6.66 6.08 3.86 3.17 1.87 1.94 1.39 38.44
 
Longmont West Avg. Temp F 29.64 40.76 48.12 49.78 55.9 69.41 74.14 68.44 62.4 48.74 44.44 31.81 51.97
Ref date as of 12/31/2017 Total Precip " 0.64 0.2 0.69 1.38 4.77 0.27 0.25 1.53 1.57 1.54 0.31 0.12 13.27
Site Type: Turf Total Alfalfa ETr " 1.75 3.03 4.64 5.48 5.85 7.46 7.18 5.85 4.63 3.41 2.51 1.73 53.52
Total Growing Degee Days from March 1 0 0 205 208 300 535 689 562 409 254 167 81 3410
Gross Pond Evap Inch 1.47 2.55 3.9 4.6 4.91 6.27 6.03 4.91 3.89 2.86 2.11 1.45 44.95
Net Pond Evap Inch 1.02 2.41 3.41 3.64 1.58 6.08 5.86 3.84 2.79 1.79 1.89 1.37 35.68
 
Fort Lupton Avg. Temp F 29.38 40.52 48.24 49.97 55.97 69.66 74.55 69.29 62.91 49.09 43.52 30.93 52
Ref date as of 12/31/2017 Total Precip " 0.59 0.29 0.74 1.83 4.65 0.21 0.21 1.81 1 1.59 0.25 0.31 13.48
Site Type: Turf Total Alfalfa ETr " 1.97 3.75 5.54 6.17 6.71 9.25 8.85 7.35 5.88 4.13 3.02 2.21 64.83
Total Growing Degee Days from March 1 0 0 223 225 319 548 696 601 429 242 170 76 3529
Gross Pond Evap Inch 1.65 3.15 4.65 5.18 5.64 7.77 7.43 6.17 4.94 3.47 2.54 1.86 54.45
Net Pond Evap Inch 1.24 2.95 4.14 3.9 2.38 7.62 7.29 4.91 4.24 2.36 2.36 1.64 45.03
 
Boulder NW Avg. Temp F 31.1 41.34 49.19 49.04 55.74 69.08 74.13 68.65 62.5 49.07 44.61 33.25 52.31
Ref date as of 12/31/2017 Total Precip " 1.08 0.59 1.2 2.04 6.27 0.51 1.24 1.26 1.86 1.92 0.63 0.43 19.03
Site Type: Turf Total Alfalfa ETr " 2.05 3.2 4.92 5.36 6.11 8 7.76 6.25 4.84 3.61 2.78 2.08 56.96
Total Growing Degee Days from March 1 0 0 215 219 316 532 668 557 404 241 157 73 3382
Gross Pond Evap Inch 1.72 2.69 4.13 4.5 5.13 6.72 6.52 5.25 4.07 3.03 2.34 1.75 47.85
Net Pond Evap Inch 0.97 2.28 3.29 3.07 0.74 6.36 5.65 4.37 2.76 1.69 1.89 1.45 34.52
 
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 32.64 42.38 49.65 48.92 55.45 68.94 73.46 68.43 62.97 51.18 47.12 36.5 53.14
Ref date as of 12/31/2017 Total Precip " 0.86 0.22 1.55 2.02 5.86 0.52 1.71 1.23 1.69 0.63 0.35 0.21 16.85
Site Type: Turf Total Alfalfa ETr " 2.17 3.51 5.23 5.4 6.09 8.08 7.76 6.34 5.09 4.06 3.39 2.65 59.77
Total Growing Degee Days from March 1 0 0 183 179 279 514 651 547 396 232 154 77 3212
Gross Pond Evap Inch 1.82 2.95 4.39 4.54 5.12 6.79 6.52 5.33 4.28 3.41 2.85 2.23 50.23
Net Pond Evap Inch 1.22 2.79 3.31 3.12 1.01 6.42 5.32 4.46 3.09 2.97 2.6 2.08 38.39
Greeley04 Avg. Temp F 27.33 37.43 45.65 49.41 55.76 68.78 73.4 67.2 61.65 46.69 40.27 27.85 50.12
Ref date as of 12/3117/2017 Total Precip " 0.19 0.08 0.64 1.42 6.67 0.28 0.25 1.84 1.19 1.43 0.19 0.04 14.22
Site Type: Fully irrigated Total Alfalfa ETr " 1.95 3.72 6.09 6.92 7.31 9.56 8.98 6.63 5.73 4.35 3.14 2.47 66.85
Total Growing Degee Days from March 1 0 0 218 233 321 529 663 560 406 241 151 57 3379
Gross Pond Evap Inch 1.64 3.12 5.12 5.81 6.14 8.03 7.54 5.57 4.81 3.65 2.64 2.07 56.14
Net Pond Evap Inch 1.51 3.07 4.67 4.82 1.47 7.83 7.37 4.28 3.98 2.65 2.5 2.05 46.2