Pond Evaporation Calculation													12/31/11
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	2010	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	or Avg.
Ovid	Avg. Temp ° F	25.69	25.91	39.3	48.91	55.67	69.93	74.56	73.58	63.18	51.23	33.93	28.51	49.2
Ref date as of 12/31/2010	Total Precip "	0.12	0.72	1.35	2.38	2.12	4.14	2.63	2.24	0.13	0.64	0.53	0.41	17.41
Site Type: Alfalfa	Total Alfalfa ETr "	1.98	1.9	4.13	5.87	6.93	8.49	9.35	8.85	7.26	5.25	3.11	2.38	65.5
Total Growing Degee Days from March 1		0	0	105	201	303	566	702	658	472	287	87	31	3412
Gross Pond Evap	Total "	1.66	1.6	3.47	4.93	5.82	7.13	7.85	7.43	6.1	4.41	2.61	2	55.01
Net Pond Evap	Total "	1.58	1.09	2.52	3.26	4.34	4.23	6.01	5.87	6.01	3.96	2.24	1.71	42.82
Crook	Avg. Temp ° F	25.44	26.24	39.21	48.21	54.48	68.52	72.54	72.03	62.28	51.11	34.4	29.67	48.68
Ref date as of 12/31/2010	Total Precip "	0.04	0.59	1.11	2.23	2.24	3.08	1.83	1.97	0.19	0.62	0.54	0.7	15.14
Site Type: Alfalfa	Total Alfalfa ETr "	2.09	1.92	4.27	6.1	7.13	8.12	8.89	8.54	7.79	5.04	3.1	2.41	65.4
Total Growing Degee Days from March 1		0	0	107	199	285	523	654	622	479	298	93	39	3299
Gross Pond Evap	Inch	1.76	1.61	3.59	5.12	5.99	6.82	7.47	7.17	6.54	4.23	2.6	2.02	54.92
Net Pond Evap	Inch	1.73	1.2	2.81	3.56	4.42	4.66	6.19	5.79	6.41	3.8	2.23	1.53	44.33
Sterling	Avg. Temp ° F	26.12	27.34	40.23	49.09	55.73	69.86	73.27	72.91	63.67	51.13	34.21	29.52	49.42
Ref date as of 12/31/2010	Total Precip "	0.08	0.62	1.16	2.68	2.26	2.42	2.66	3.46	0.07	1.1	0.71	0.33	17.55
Site Type: Alfalfa	Total Alfalfa ETr "	1.95	2.08	4.43	6.45	7.62	8.98	9.53	9.14	7.83	4.77	2.82	2.28	67.88
Total Growing Degee Days from March 1		0	0	118	216	309	564	666	647	492	302	92	38	3444
Gross Pond Evap	Inch	1.64	1.75	3.72	5.42	6.4	7.54	8.01	7.68	6.58	4.01	2.37	1.92	57.04
Net Pond Evap	Inch	1.58	1.31	2.91	3.54	4.82	5.85	6.14	5.26	6.53	3.24	1.87	1.68	44.73
Brush	Avg. Temp ° F	26.7	27.74	40.2	49.05	56.22	69.67	73.4	73.28	63.62	51.74	34.95	30.07	49.72
Ref date as of 12/31/2010	Total Precip "	0.03	0.27	0.64	3.05	2.25	5.75	1.05	1.79	0.09	0.91	0.39	0.2	16.42
Site Type: Alfalfa	Total Alfalfa ETr "	2	2.06	4.56	6.69	8.43	8.9	8.44	8.98	7.03	5.06	3.05	2.48	67.68
Total Growing Degee Days from March 1		0	0	124	213	325	566	675	672	476	309	96	43	3499
Gross Pond Evap	Inch	1.68	1.73	3.83	5.62	7.08	7.48	7.09	7.54	5.91	4.25	2.56	2.08	56.85
Net Pond Evap	Inch	1.66	1.54	3.38	3.48	5.51	3.45	6.35	6.29	5.84	3.61	2.29	1.94	45.34
Fort Morgan	Avg. Temp ° F	26.78	28.11	40.32	48.94	55.93	69.07	73.41	72.98	64.73	52.78	35.63	31.05	49.98
Ref date as of 12/31/2010	Total Precip "	0.05	0.36	0.85	3.84	2.01	4.87	1.43	3.97	0.12	0.54	0.45	0.42	18.91
Site Type: Turf	Total Alfalfa ETr "	1.87	1.94	4.09	5.84	7.46	8.14	8.74	8.25	7.02	4.71	2.57	2.23	62.86
Total Growing Degee Days from March 1		0	0	121	204	314	550	672	666	498	320	99	46	3490
Gross Pond Evap	Inch	1.57	1.63	3.44	4.91	6.27	6.84	7.34	6.93	5.9	3.96	2.16	1.87	52.82
Net Pond Evap	Inch	1.54	1.38	2.84	2.22	4.86	3.43	6.34	4.15	5.81	3.58	1.84	1.58	39.57
Wiggins	Avg. Temp ° F	26.35	27.6	39.85	48.09	55.35	68.94	73.18	73.11	64.36	52.38	34.66	29.88	49.48
Ref date as of 12/31/2010	Total Precip "	0.04	0.37	0.44	2.6	1.75	2.68	1.43	0.72	0.06	0.78	1.87	0.2	12.94
Site Type: Alfalfa	Total Alfalfa ETr "	1.95	2.05	4.51	6.44	8.18	8.93	9.66	9.79	8.07	5.46	3.03	2.67	70.74
Total Growing Degee Days from March 1		0	0	116	200	310	541	663	659	492	321	93	43	3438
Gross Pond Evap	Inch	1.64	1.72	3.79	5.41	6.87	7.5	8.11	8.22	6.78	4.59	2.55	2.24	59.42
Net Pond Evap	Inch	1.61	1.46	3.48	3.59	5.65	5.63	7.11	7.72	6.74	4.04	1.24	2.1	50.37
Fort Collins East	Avg. Temp ° F	26.38	27.14	39.35	46.26	53.09	66.68	70.24	68.49	61.34	51.18	34.15	30.77	47.92
Ref date as of 12/31/2010	Total Precip "	0.01	0.23	0.7	4	1.87	1.37	1.28	0.79	0.11	0.8	0.89	0.17	12.22
Site Type: Alfalfa	Total Alfalfa ETr "	1.67	1.8	4.47	5.62	6.85	8.08	8.45	7.11	6.97	4.64	2.54	2.45	60.65
Total Growing Degee Days from March 1		0	0	108	152	260	490	592	574	444	268	72	37	2997
Gross Pond Evap	Inch	1.4	1.51	3.75	4.72	5.75	6.79	7.1	5.97	5.85	3.9	2.13	2.06	50.93
Net Pond Evap	Inch	1.4	1.35	3.26	1.92	4.45	5.83	6.2	5.42	5.78	3.34	1.51	1.94	42.4
Eaton	Avg. Temp ° F	24.93	25.95	39.22	46.93	54.15	67.21	70.59	69.87	62.31	51.88	34.09	30.43	48.13
Ref date as of 12/31/2010	Total Precip "	0.09	0.59	0.68	3.15	2.25	2.04	3.72	1.44	0.07	0.65	0.93	0.25	15.86
Site Type: Alfalfa	Total Alfalfa ETr "	1.56	1.85	4.34	5.93	7.77	8.26	8.5	7.82	7.12	4.76	2.54	2.49	62.94
Total Growing Degee Days from March 1		0	0	102	172	290	504	607	609	459	288	73	39	3143
Gross Pond Evap	Inch	1.31	1.55	3.65	4.98	6.53	6.94	7.14	6.57	5.98	4	2.13	2.09	52.87
Net Pond Evap	Inch	1.25	1.14	3.17	2.78	4.95	5.51	4.54	5.56	5.93	3.54	1.48	1.92	41.77
Johnsons Corner	Avg. Temp ° F	26.1	27.23	39.74	46.53	52.62	66.97	70.89	70.4	63.66	53.56	36.64	32.95	48.94
Ref date as of 12/31/2010	Total Precip "	0.23	0.53	1.02	3.53	2.12	1.73	2.34	0.44	0.13	0.57	0.83	0.26	13.73
Site Type: Alfalfa	Total Alfalfa ETr "	1.69	1.61	4.27	5.21	6.16	7.88	8.31	8.11	7.07	4.62	2.54	2.5	59.97
Total Growing Degee Days from March 1		0	0	102	150	254	499	608	614	459	291	87	44	3108
Gross Pond Evap	Inch	1.42	1.35	3.59	4.38	5.17	6.62	6.98	6.81	5.94	3.88	2.13	2.1	50.37
Net Pond Evap	Inch	1.26	0.98	2.87	1.91	3.69	5.41	5.34	6.5	5.85	3.48	1.55	1.92	40.76
Gilcrest	Avg. Temp ° F	23.42	27.09	39.46	47.08	53.75	67.78	71.54	70.51	62.2	51.02	34.12	29.68	48.14
Ref date as of 12/31/2010	Total Precip "	0.07	0.45	0.79	3.08	2.02	2.1	0.41	1.39	0.11	0.49	0.8	0.1	11.81
Site Type: Alfalfa	Total Alfalfa ETr "	1.34	1.57	4.18	5.55	7.14	8.17	8.43	7.78	6.76	4.21	2.4	2.29	59.82
Total Growing Degee Days from March 1		0	0	104	169	286	515	614	619	464	294	82	34	3181
Gross Pond Evap	Inch	1.13	1.32	3.51	4.66	6	6.86	7.08	6.54	5.68	3.54	2.02	1.92	50.26
Net Pond Evap	Inch	1.08	1	2.96	2.51	4.58	5.39	6.79	5.56	5.6	3.19	1.46	1.85	41.97
Longmont South	Avg. Temp ° F	27.64	28.08	40.84	47.69	53.65	67.71	71.44	71.43	63.88	53.68	37.25	34.07	49.78
Ref date as of 12/31/2010	Total Precip "	0.37	0.8	1.22	2.99	1.68	1.8	1.1	0.67	0.13	0.89	0.6	0.37	12.62
Site Type: Alfalfa	Total Alfalfa ETr "	1.78	1.66	4.22	5.55	6.74	7.77	8.14	8.12	6.98	4.76	2.71	2.79	61.22
Total Growing Degee Days from March 1		0	0	105	155	259	501	619	625	452	287	90	56	3149
Gross Pond Evap	Inch	1.5	1.39	3.54	4.66	5.66	6.53	6.84	6.82	5.86	4	2.28	2.34	51.42
Net Pond Evap	Inch	1.24	0.83	2.69	2.57	4.49	5.27	6.07	6.35	5.77	3.38	1.86	2.08	42.6
Fort Collins NW	Avg. Temp ° F	26.75	27.07	39.75	46.19	52.76	66.22	70.68	69.97	62.22	51.28	35.03	32	48.33
Ref date as of 12/31/2010	Total Precip "	0.15	0.39	0.93	2.6	1.93	1.93	0.84	0.52	0.03	0.72	0.46	0.01	10.51
Site Type: Turf	Total Alfalfa ETr "	1.34	1.4	3.72	4.7	2.29	1.21	0.73	-0.95	-2.02	-2.41	-2.59	-3.2	15.39
Total Growing Degee Days from March 1		0	0	97	138	247	477	594	597	442	258	67	30	2947
Gross Pond Evap	Inch	1.13	1.18	3.12	3.95	1.92	1.02	0.61	0	0	0	0	0	12.93
Net Pond Evap	Inch	1.02	0.9	2.47	2.13	0.57	0	0.03	0	0	0	0	0	7.12
Fort Collins Central	Avg. Temp ° F	26.72	27.74	40.18	46.92	53.98	67.38	71.73	70.82	62.54	51.35	35.2	32.04	48.88
Ref date as of 12/31/2010	Total Precip "	0.16	0.38	1.1	2.8	1.89	2.02	1.27	1.13	0.04	1.01	0.7	0.02	12.52
Site Type: Turf	Total Alfalfa ETr "	1.37	1.49	3.72	4.76	6.07	6.71	7.26	6.68	5.41	3.47	2	1.78	50.72
Total Growing Degee Days from March 1		0	0	102	146	268	504	618	621	459	279	80	39	3116
Gross Pond Evap	Inch	1.15	1.25	3.12	4	5.1	5.64	6.1	5.61	4.54	2.91	1.68	1.5	42.6
Net Pond Evap	Inch	1.04	0.99	2.35	2.04	3.78	4.22	5.21	4.82	4.52	2.21	1.19	1.48	33.85
Windsor	Avg. Temp ° F	27.36	28.47	40.76	47.54	54.3	68.11	72.94	72.42	65.29	53.66	36.32	21.85	49.09
Ref date as of 12/31/2010	Total Precip "	0.21	0.51	1.06	3.43	2.32	1.33	1.05	0.33	0.04	0.51	1.03	0.17	11.99
Site Type: Dryland Pasture	Total Alfalfa ETr "	1.16	1.39	3.5	4.69	6.07	6.81	7.87	6.81	5.55	3.2	1.76	1.22	50.03
Total Growing Degee Days from March 1		0	0	115	182	297	532	643	649	490	314	91	35	3348
Gross Pond Evap	Inch	0.97	1.17	2.94	3.94	5.1	5.72	6.61	5.72	4.66	2.69	1.48	1.02	42.02
Net Pond Evap	Inch	0.83	0.81	2.2	1.54	3.47	4.79	5.88	5.49	4.63	2.33	0.76	0.91	33.64
Greeley West	Avg. Temp ° F	25.41	27.3	39.68	47.04	53.98	67.97	72.18	71.55	63.53	52.24	34.7	30.48	48.84
Ref date as of 12/31/2010	Total Precip "	0.05	0.32	0.46	3.88	2.12	2.24	1.86	1.15	0.07	0.38	0.82	0	13.35
Site Type: Turf	Total Alfalfa ETr "	1.13	1.5	3.78	5.45	7.03	7.81	8.31	7.86	6.26	4.02	1.98	1.86	56.99
Total Growing Degee Days from March 1		0	0	97	162	277	521	639	639	467	293	75	32	3202
Gross Pond Evap	Inch	0.95	1.26	3.18	4.58	5.91	6.56	6.98	6.6	5.26	3.38	1.66	1.56	47.88
Net Pond Evap	Inch	0.91	1.04	2.85	1.86	4.42	4.99	5.68	5.8	5.21	3.11	1.09	1.56	38.52
Loveland	Avg. Temp ° F	27.31	28.1	41.11	47.96	54.41	68.33	72.92	72.03	64.06	53.26	36.64	32.76	49.91
Ref date as of 12/31/2010	Total Precip "	0.17	0.24	0.68	2.99	1.79	1.89	2.51	0.72	0.05	0.49	0.53	0	12.06
Site Type: Turf	Total Alfalfa ETr "	1.3	1.46	3.8	4.97	6.38	7.41	8	7.28	6	3.86	2.02	1.85	54.33
Total Growing Degee Days from March 1		0	0	115	166	286	537	662	657	482	302	91	40	3338
Gross Pond Evap	Inch	1.09	1.23	3.19	4.17	5.36	6.22	6.72	6.12	5.04	3.24	1.7	1.55	45.63
Net Pond Evap	Inch	0.97	1.06	2.72	2.08	4.11	4.9	4.96	5.61	5.01	2.9	1.33	1.55	37.2
Berthoud	Avg. Temp ° F	26.02	26.48	38.91	45.89	52.23	66.43	70.84	70.38	63.58	52.5	36.03	32.81	48.51
Ref date as of 12/31/2010	Total Precip "	0.23	0.61	1.37	3.27	2.01	1.54	1.83	0.29	0.08	0.52	0.6	0.28	12.63
Site Type: Turf	Total Alfalfa ETr "	1.45	1.5	3.82	5.03	6.39	7.45	7.72	7.5	6.57	4.08	2.24	2.22	55.97
Total Growing Degee Days from March 1		0	0	90	135	244	497	611	611	449	256	75	33	3001
Gross Pond Evap	Inch	1.22	1.26	3.21	4.23	5.37	6.26	6.48	6.3	5.52	3.43	1.88	1.86	47.02
Net Pond Evap	Inch	1.06	0.83	2.25	1.94	3.96	5.18	5.2	6.1	5.46	3.06	1.46	1.67	38.17
Longmont West	Avg. Temp ° F	28.9	29.55	42.29	49.73	55.97	70.16	74.66	73.79	65.73	54.5	38.07	35.09	51.54
Ref date as of 12/31/2010	Total Precip "	0.16	0.47	1.19	3.08	1.76	1.7	1.18	0.74	0.1	0.64	0.7	0	11.72
Site Type: Turf	Total Alfalfa ETr "	1.34	1.44	3.67	5.08	6.32	6.94	7.42	6.77	5.55	3.49	2	1.96	51.98
Total Growing Degee Days from March 1		0	0	116	180	295	562	688	685	479	299	95	55	3454
Gross Pond Evap	Inch	1.13	1.21	3.08	4.27	5.31	5.83	6.23	5.69	4.66	2.93	1.68	1.65	43.67
Net Pond Evap	Inch	1.01	0.88	2.25	2.11	4.08	4.64	5.41	5.17	4.59	2.48	1.19	1.65	35.46
Fort Lupton	Avg. Temp ° F	27.49	28.47	40.48	47.5	54.17	68.1	72.55	72.19	64.95	54.01	37.44	33.56	50.08
Ref date as of 12/31/2010	Total Precip "	0.05	0.21	0.47	2.56	2.33	2.81	0.91	1.24	0.38	0.8	0.55	0.01	12.32
Site Type: Turf	Total Alfalfa ETr "	1.95	1.97	4.54	6.07	7.7	8.79	9.46	8.93	7.79	4.94	2.66	2.52	67.32
Total Growing Degee Days from March 1		0	0	100	168	277	523	654	653	470	298	86	50	3279
Gross Pond Evap	Inch	1.64	1.65	3.81	5.1	6.47	7.38	7.95	7.5	6.54	4.15	2.23	2.12	56.54
Net Pond Evap	Inch	1.6	1.51	3.48	3.31	4.84	5.42	7.31	6.63	6.28	3.59	1.85	2.11	47.93
Boulder NW	Avg. Temp ° F	30.64	28.4	40.4	46.97	53.3	67.83	72.55	72.28	65.27	53.67	38.71	35.41	50.45
Ref date as of 12/31/2010	Total Precip "	0.26	0.8	1.79	4.35	2.8	2.45	2.13	0.61	0.2	0.82	0.52	0.09	16.82
Site Type: Turf	Total Alfalfa ETr "	1.97	1.74	3.96	5.06	6.41	7.28	8.23	8.26	6.78	4.33	2.47	2.24	58.73
Total Growing Degee Days from March 1		0	0	107	159	265	515	646	650	489	292	99	61	3283
Gross Pond Evap	Inch	1.65	1.46	3.33	4.25	5.38	6.12	6.91	6.94	5.7	3.64	2.07	1.88	49.33
Net Pond Evap	Inch	1.47	0.9	2.07	1.21	3.42	4.4	5.42	6.51	5.56	3.06	1.71	1.82	37.55
Boulder East	Avg. Temp ° F	29.67	29	42.01	48.78	44.85	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	38.86
Ref date as of 5/2/2010	Total Precip "	0.17	0.95	1.39	2.94	0	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	5.45
Site Type: Turf	Total Alfalfa ETr "	1.42	1.55	3.91	5.26	0.34	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	12.48
Total Growing Degee Days from March 1		0	0	106	157	5	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	268
Gross Pond Evap	Inch	1.19	1.3	3.28	4.42	0.29	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	10.48
Net Pond Evap	Inch	1.07	0.64	2.31	2.36	0.29	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	6.67
Boulder Flatiron	Avg. Temp ° F	27.35	27.1	39.63	46.87	42.6	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	36.71
Ref date as of 5/2/2010	Total Precip "	0.12	0.41	1.57	3.08	0	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	5.18
Site Type: Turf	Total Alfalfa ETr "	1.34	1.32	3.2	4.41	0.28	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	10.55
Total Growing Degee Days from March 1		0	0	95	144	4	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	243
Gross Pond Evap	Inch	1.13	1.11	2.69	3.7	0.24	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	8.87
Net Pond Evap	Inch	1.04	0.82	1.59	1.55	0.24	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	#N/A	5.24
Boulder SW	Avg. Temp ° F	33.83	30.62	42.54	48.53	54.28	68.3	73.38	72.96	66.93	54.79	39.86	36.82	51.9
Ref date as of 12/31/2010	Total Precip "	0.22	0.83	1.78	3.36	2.81	2.45	2.27	1.1	0.28	0.94	0.48	0.25	16.77
Site Type: Turf	Total Alfalfa ETr "	2.07	1.73	4.05	5.13	6.35	6.88	7.22	7.68	6.64	4.37	2.72	2.59	57.43
Total Growing Degee Days from March 1		0	0	92	140	249	516	665	672	476	253	79	52	3194
Gross Pond Evap	Inch	1.74	1.45	3.4	4.31	5.33	5.78	6.06	6.45	5.58	3.67	2.28	2.18	48.23
Net Pond Evap	Inch	1.58	0.87	2.16	1.96	3.37	4.06	4.48	5.68	5.38	3.01	1.95	2	36.5
Greeley04	Avg. Temp ° F	25.04	26.96	39.13	47	54.31	67.84	71.44	70.47	62.94	51.73	33.57	30.28	48.39
Ref date as of 123110/0/2010	Total Precip "	0.03	0.26	0.28	3.32	1.97	3.17	1.64	1.63	0.01	0.55	0.34	0.01	13.21
Site Type: Fully irrigated	Total Alfalfa ETr "	1.46	1.94	4.54	6.57	8.6	9.1	8.23	7.4	6.78	4.42	2.41	2.31	63.76
Total Growing Degee Days from March 1		0	0	106	182	297	525	608	623	474	298	77	36	3226
Gross Pond Evap	Inch	1.23	1.63	3.81	5.52	7.22	7.64	6.91	6.22	5.7	3.71	2.02	1.94	53.55
Net Pond Evap	Inch	1.21	1.45	3.62	3.19	5.85	5.43	5.77	5.08	5.69	3.33	1.79	1.93	44.34