Pond Evaporation Calculation													12/28/20
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	2020	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	or Avg.
Ovid	Avg. Temp ° F	30.15	30.43	40.88	46.44	57.85	73.43	75.01	74.49	61.51	44.6	39.8	31.53	50.51
Ref date as of 122820//2020	Total Precip "	0.35	0.28	1.27	0.54	2.97	1.52	1.5	0.51	0.76	0.19	0.29	0.2	10.38
Site Type: Alfalfa	Total Alfalfa ETr "	2.35	2.96	4.15	7.13	7.59	11.48	10.08	9.25	6.45	4.41	3.18	1.94	70.97
Total Growing Degee Days from March 1		0	0	129	242	340	609	707	665	427	251	169	60	3599
Gross Pond Evap	Total "	1.97	2.49	3.49	5.99	6.38	9.64	8.47	7.77	5.42	3.7	2.67	1.63	59.62
Net Pond Evap	Total "	1.73	2.29	2.6	5.61	4.3	8.58	7.42	7.41	4.89	3.57	2.47	1.49	52.36
Crook	Avg. Temp ° F	30.71	29.8	40	45.96	57.35	71.98	74.31	74.37	60.64	44.25	39.28	31.48	50.01
Ref date as of 122820//2020	Total Precip "	0.11	0.23	1.1	0.4	1.82	2.01	1.72	0.44	0.89	0.34	0.26	0.25	9.57
Site Type: Alfalfa	Total Alfalfa ETr "	2.4	2.76	3.79	6.49	7.29	10.61	8.75	8.06	5.65	4.05	2.92	1.97	64.74
Total Growing Degee Days from March 1		0	0	124	235	337	580	685	658	425	260	166	64	3534
Gross Pond Evap	Inch	2.02	2.32	3.18	5.45	6.12	8.91	7.35	6.77	4.75	3.4	2.45	1.65	54.37
Net Pond Evap	Inch	1.94	2.16	2.41	5.17	4.85	7.51	6.15	6.46	4.12	3.16	2.27	1.48	47.68
Sterling	Avg. Temp ° F	31.77	29.68	40.89	46.59	58.57	72.21	74.53	74.87	60.41	44.52	38.92	28.94	50.16
Ref date as of 122820//2020	Total Precip "	0.09	0.15	0.79	0.35	2.59	1.69	2.6	0.46	1.03	0.17	0.25	0.36	10.53
Site Type: Alfalfa	Total Alfalfa ETr "	2.37	2.54	3.8	6.33	7.54	10.26	9.25	8.63	5.75	4.26	2.9	1.59	65.22
Total Growing Degee Days from March 1		0	0	134	234	361	582	691	673	416	261	153	49	3554
Gross Pond Evap	Inch	1.99	2.13	3.19	5.32	6.33	8.62	7.77	7.25	4.83	3.58	2.44	1.34	54.79
Net Pond Evap	Inch	1.93	2.03	2.64	5.07	4.52	7.44	5.95	6.93	4.11	3.46	2.26	1.08	47.42
Brush	Avg. Temp ° F	31.07	28.82	40.45	46.1	58.43	70.56	73.39	72.93	59.12	44.25	37.1	27.13	49.11
Ref date as of 122820//2020	Total Precip "	0.14	0.24	1.06	0.43	1.68	2.09	1.09	2.22	1.04	0.3	0.55	0.45	11.29
Site Type: Alfalfa	Total Alfalfa ETr "	2.27	2.35	3.85	6.02	7.56	9.71	8.81	7.69	5.35	4.22	2.8	1.42	62.05
Total Growing Degee Days from March 1		0	0	140	241	381	546	647	634	423	273	154	40	3479
Gross Pond Evap	Inch	1.91	1.97	3.23	5.06	6.35	8.16	7.4	6.46	4.49	3.54	2.35	1.19	52.11
Net Pond Evap	Inch	1.81	1.81	2.49	4.76	5.17	6.69	6.64	4.91	3.77	3.33	1.97	0.88	44.23
Fort Morgan	Avg. Temp ° F	32.04	29.36	40.7	46.48	59.45	71.33	74.14	74.03	60.63	44.52	38.04	28.31	49.92
Ref date as of 122820//2020	Total Precip "	0.25	0.36	1.44	1.32	1.83	2.28	0.73	1.82	1.04	0.17	0.44	0.29	11.97
Site Type: Turf	Total Alfalfa ETr "	2.17	2.28	3.69	5.73	7.61	9.47	8.71	7.85	5.37	3.67	2.56	1.51	60.62
Total Growing Degee Days from March 1		0	0	131	231	401	571	685	672	425	269	146	41	3572
Gross Pond Evap	Inch	1.82	1.92	3.1	4.81	6.39	7.95	7.32	6.59	4.51	3.08	2.15	1.27	50.91
Net Pond Evap	Inch	1.65	1.66	2.09	3.89	5.11	6.36	6.81	5.32	3.78	2.96	1.84	1.07	42.54
Wiggins	Avg. Temp ° F	31.87	29.27	39.9	45.96	59.02	71.02	74.05	73.25	59.72	43.63	36.83	27.48	49.33
Ref date as of 122820//2020	Total Precip "	0.08	0.13	1.5	0.61	1.6	0.98	0.55	0.53	0.76	0.19	0.39	0.4	7.72
Site Type: Alfalfa	Total Alfalfa ETr "	2.22	2.46	3.87	6.15	7.91	10.11	9.65	8.48	5.62	3.94	2.68	1.5	64.59
Total Growing Degee Days from March 1		0	0	137	230	384	565	664	647	418	268	139	41	3493
Gross Pond Evap	Inch	1.86	2.07	3.25	5.17	6.64	8.49	8.11	7.12	4.72	3.31	2.25	1.26	54.25
Net Pond Evap	Inch	1.81	1.98	2.2	4.74	5.52	7.81	7.72	6.75	4.19	3.18	1.98	0.98	48.86
Fort Collins East	Avg. Temp ° F	32.81	28.01	39.55	44.35	57.43	68.63	72.25	70.94	58.85	44.21	39.49	31.26	48.98
Ref date as of 122820//2020	Total Precip "	0.02	0.47	0.97	1.19	2.11	1.23	0.16	0.21	0.75	6.64	0.51	12.27	26.53
Site Type: Alfalfa	Total Alfalfa ETr "	2.48	2.44	4.07	5.86	6.91	8.69	8.77	7.52	5.22	3.99	2.73	1.88	60.56
Total Growing Degee Days from March 1		0	0	119	198	348	531	628	596	397	233	133	53	3236
Gross Pond Evap	Inch	2.08	2.05	3.42	4.92	5.8	7.3	7.37	6.32	4.38	3.35	2.29	1.58	50.86
Net Pond Evap	Inch	2.07	1.72	2.74	4.09	4.33	6.44	7.25	6.17	3.86	0	1.94	0	40.61
Eaton	Avg. Temp ° F	31.36	27.63	38.9	44.4	57.94	68.79	71.7	70.82	59.1	43.55	38.53	30.35	48.59
Ref date as of 122820//2020	Total Precip "	0.01	0.36	1.16	0.83	1.02	1.24	0.33	1.04	0.59	0.6	0.27	0.23	7.68
Site Type: Alfalfa	Total Alfalfa ETr "	2	2.23	3.93	6.07	8.12	9.2	8.69	7.17	5.22	3.94	2.59	1.71	60.87
Total Growing Degee Days from March 1		0	0	112	207	370	531	624	610	413	252	126	50	3295
Gross Pond Evap	Inch	1.68	1.87	3.3	5.1	6.82	7.73	7.3	6.02	4.38	3.31	2.18	1.44	51.13
Net Pond Evap	Inch	1.67	1.62	2.49	4.52	6.11	6.86	7.07	5.29	3.97	2.89	1.99	1.28	45.76
Johnsons Corner	Avg. Temp ° F	33.56	28.03	40.67	45.35	57.79	69.2	72.99	73.05	62.5	47.41	42.05	33.11	50.48
Ref date as of 122820//2020	Total Precip "	0.05	0.93	1.4	1.67	2.19	1.74	0.24	0.16	0.93	0.62	0.33	0.35	10.61
Site Type: Alfalfa	Total Alfalfa ETr "	2.23	2.02	3.86	5.45	6.83	8.73	9.08	7.94	5.51	4.16	2.73	1.76	60.3
Total Growing Degee Days from March 1		0	0	100	192	350	542	668	651	421	248	142	52	3366
Gross Pond Evap	Inch	1.87	1.7	3.24	4.58	5.74	7.33	7.63	6.67	4.63	3.49	2.29	1.48	50.65
Net Pond Evap	Inch	1.84	1.05	2.26	3.41	4.2	6.12	7.46	6.56	3.98	3.06	2.06	1.23	43.23
Gilcrest	Avg. Temp ° F	31.96	25.6	40.16	45.27	59.26	70.27	72.97	72.22	60.01	44.19	37.94	27.3	48.93
Ref date as of 122820//2020	Total Precip "	0.05	0.78	1.92	1.18	1.13	2.17	1.01	1.23	0.8	1.36	0.24	0.36	12.23
Site Type: Alfalfa	Total Alfalfa ETr "	2.03	1.89	3.82	5.64	7.76	9.26	9.13	8.18	5.34	3.8	2.49	1.44	60.78
Total Growing Degee Days from March 1		0	0	115	214	385	554	650	625	416	258	144	44	3405
Gross Pond Evap	Inch	1.71	1.59	3.21	4.74	6.52	7.78	7.67	6.87	4.49	3.19	2.09	1.21	51.07
Net Pond Evap	Inch	1.67	1.04	1.86	3.91	5.73	6.26	6.96	6.01	3.93	2.24	1.92	0.96	42.49
Longmont South	Avg. Temp ° F	34.49	28.16	41.69	45.8	58.28	68.92	71.89	71.3	60.67	46.27	40.96	32.02	50.04
Ref date as of 122820//2020	Total Precip "	0.12	0.97	1.6	1.43	1.84	2.03	0.48	0.22	0.95	0.68	0.36	0.28	10.96
Site Type: Alfalfa	Total Alfalfa ETr "	2.6	2.22	4.1	5.78	7.11	8.68	8.06	7	5.06	3.75	2.77	1.76	58.89
Total Growing Degee Days from March 1		0	0	117	198	353	526	621	599	417	246	141	60	3278
Gross Pond Evap	Inch	2.18	1.86	3.44	4.86	5.97	7.29	6.77	5.88	4.25	3.15	2.33	1.48	49.46
Net Pond Evap	Inch	2.1	1.19	2.32	3.85	4.68	5.87	6.43	5.73	3.59	2.67	2.07	1.28	41.78
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	33.69	29.06	40.35	46.07	58.57	68.78	72.85	71.74	59.15	44.33	39.12	30.99	49.56
Ref date as of 122820//2020	Total Precip "	0.01	0.36	1.18	1.2	2.21	1.44	0.35	0.18	1.14	0.46	0.58	0.18	9.29
Site Type: Turf	Total Alfalfa ETr "	2.14	2.16	3.63	5.21	6.49	7.5	7.7	6.48	4.53	3.28	2.52	1.62	53.26
Total Growing Degee Days from March 1		0	0	117	207	358	524	622	601	409	247	135	57	3277
Gross Pond Evap	Inch	1.8	1.81	3.05	4.38	5.45	6.3	6.47	5.44	3.81	2.76	2.12	1.36	44.75
Net Pond Evap	Inch	1.79	1.56	2.22	3.54	3.9	5.29	6.22	5.32	3.01	2.43	1.71	1.23	38.22
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	33.48	29.28	41.55	46.88	60.16	71.49	75.5	75.05	62.43	46.17	40.53	31.73	51.19
Ref date as of 122820//2020	Total Precip "	0.05	0.59	1.64	1.61	1.06	1.07	0.18	6.61	0.8	0.51	0.29	2.54	16.95
Site Type: Turf	Total Alfalfa ETr "	1.99	2.1	3.74	5.45	7.38	8.19	8.48	7.08	4.86	3.25	2.29	1.49	56.3
Total Growing Degee Days from March 1		0	0	133	233	396	581	698	676	444	263	143	60	3627
Gross Pond Evap	Inch	1.67	1.76	3.14	4.58	6.2	6.88	7.12	5.95	4.08	2.73	1.92	1.25	47.28
Net Pond Evap	Inch	1.64	1.35	1.99	3.45	5.46	6.13	7	1.32	3.52	2.37	1.72	0	35.95
Loveland	Avg. Temp ° F	34.04	29.53	41.75	46.69	59.74	70.41	74.1	73.59	60.88	45.62	40.26	31.43	50.67
Ref date as of 122820//2020	Total Precip "	0	1.15	1.62	2.07	2.54	2.25	0.39	0.37	1.04	0.82	0.46	0.29	13
Site Type: Turf	Total Alfalfa ETr "	2.1	2.11	3.68	5.17	6.74	7.81	7.76	6.71	4.66	3.35	1.54	1.46	53.09
Total Growing Degee Days from March 1		0	0	141	225	397	575	684	663	438	267	163	75	3628
Gross Pond Evap	Inch	1.76	1.77	3.09	4.34	5.66	6.56	6.52	5.64	3.91	2.81	1.29	1.23	44.58
Net Pond Evap	Inch	1.76	0.97	1.96	2.89	3.88	4.99	6.25	5.38	3.19	2.24	0.97	1.02	35.5
Berthoud	Avg. Temp ° F	33.68	28.3	40.9	45.83	58.54	69.59	73.47	74.12	62.58	47.25	41.75	32.37	50.7
Ref date as of 122820//2020	Total Precip "	0	0.85	1.47	1.85	2.11	5.04	0.33	0.12	0.9	0.54	0.3	0.29	13.8
Site Type: Turf	Total Alfalfa ETr "	2.25	2.03	3.75	5.4	7.02	8.52	8.54	7.96	5.34	3.85	2.58	1.66	58.9
Total Growing Degee Days from March 1		0	0	106	201	367	555	678	679	439	253	139	51	3468
Gross Pond Evap	Inch	1.89	1.71	3.15	4.54	5.9	7.16	7.17	6.69	4.49	3.23	2.17	1.39	49.49
Net Pond Evap	Inch	1.89	1.11	2.12	3.24	4.42	3.63	6.94	6.6	3.86	2.86	1.96	1.19	39.82
Longmont West	Avg. Temp ° F	34.91	29.52	42.15	46.84	59.8	70.51	74.34	74.02	62.27	47.07	41.36	31.66	51.2
Ref date as of 122820//2020	Total Precip "	0	0.74	1.41	1.01	2.14	1.85	1.67	0.52	1.15	0.22	0.16	0.24	11.11
Site Type: Turf	Total Alfalfa ETr "	2.17	2.05	3.57	5.11	6.85	7.69	7.68	6.69	4.77	3.31	2.5	1.49	53.88
Total Growing Degee Days from March 1		0	0	0	0	0	0	0	0	0	0	0	0	0
Gross Pond Evap	Inch	1.82	1.72	3	4.29	5.75	6.46	6.45	5.62	4.01	2.78	2.1	1.25	45.25
Net Pond Evap	Inch	1.82	1.2	2.01	3.59	4.26	5.16	5.28	5.26	3.2	2.63	1.99	1.08	37.48
Fort Lupton	Avg. Temp ° F	33.88	28.32	41.41	46.31	59.16	70.83	74.68	74.84	63.15	47.71	41.9	32.41	51.22
Ref date as of 122820//2020	Total Precip "	0.3	0.97	1.87	0.69	1.24	0.93	0.31	0.19	0.72	0.52	0.4	0.39	8.53
Site Type: Turf	Total Alfalfa ETr "	2.35	2.21	4.08	5.74	7.94	10.01	9.9	9.1	6.11	4.3	3.05	1.77	66.56
Total Growing Degee Days from March 1		0	0	113	207	381	577	694	681	460	268	157	55	3593
Gross Pond Evap	Inch	1.97	1.86	3.43	4.82	6.67	8.41	8.32	7.64	5.13	3.61	2.56	1.49	55.91
Net Pond Evap	Inch	1.76	1.18	2.12	4.34	5.8	7.76	8.1	7.51	4.63	3.25	2.28	1.21	49.94
Boulder NW	Avg. Temp ° F	35.72	30.41	42.12	46.5	58.55	70.01	74.12	74.24	63.43	48.28	42.99	35.75	51.84
Ref date as of 122820//2020	Total Precip "	0.03	1.7	2.34	1.63	1.63	2.04	0.62	0.49	1.22	0.49	0.74	0.33	13.26
Site Type: Turf	Total Alfalfa ETr "	2.49	2.37	3.9	5.48	6.92	8.22	8.11	7.44	5.55	3.59	1.66	1.11	56.84
Total Growing Degee Days from March 1		0	0	111	201	353	540	660	661	444	262	144	65	3441
Gross Pond Evap	Inch	2.09	1.99	3.28	4.6	5.81	6.9	6.81	6.25	4.66	3.02	1.39	0.93	47.73
Net Pond Evap	Inch	2.07	0.8	1.64	3.46	4.67	5.48	6.38	5.91	3.81	2.67	0.88	0.7	38.47
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	37.82	32.34	43.13	47.56	59.03	70.27	74.65	74.8	64.83	50.38	45.34	37.53	53.14
Ref date as of 122820//2020	Total Precip "	0	0	0	0	0.19	2.19	0.7	0.46	1.36	0.41	0.67	0.32	6.3
Site Type: Turf	Total Alfalfa ETr "	2.78	2.58	3.88	5.35	6.4	8.03	7.86	7.14	5.44	3.99	3.1	2.17	58.72
Total Growing Degee Days from March 1		0	0	101	186	344	533	678	644	443	280	139	53	3401
Gross Pond Evap	Inch	2.34	2.17	3.26	4.49	5.38	6.75	6.6	6	4.57	3.35	2.6	1.82	49.33
Net Pond Evap	Inch	2.34	2.17	3.26	4.49	5.24	5.21	6.11	5.68	3.62	3.06	2.14	1.6	44.92
Greeley04	Avg. Temp ° F	31.69	28.86	39.6	45.79	59.15	70.29	73.2	72.13	60.18	43.75	38.13	27.76	49.21
Ref date as of 12/31/2020	Total Precip "	0	0.11	1.3	0.34	1.18	1.1	0.21	0.77	0.43	0.04	0.06	0.18	5.72
Site Type: Fully irrigated	Total Alfalfa ETr "	2.45	2.49	4.2	6.35	9.28	9.8	9.57	7.9	5.93	4.16	2.86	2.18	67.17
Total Growing Degee Days from March 1		0	0	122	222	392	577	658	633	421	245	130	52	3452
Gross Pond Evap	Inch	2.06	2.09	3.53	5.33	7.8	8.23	8.04	6.64	4.98	3.49	2.4	1.83	56.42
Net Pond Evap	Inch	2.06	2.01	2.62	5.1	6.97	7.46	7.89	6.1	4.68	3.47	2.36	1.71	52.43