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	2006	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	or Avg.
Ovid	Avg. Temp ° F	35.9	28.26	37.09	52.46	60.88	72.67	77.99	72.05	57.48	46.39	36.97	28.75	50.57
Ref date as of 12/31/2006	Total Precip "	0.72	0.42	0.85	1.12	1.12	1.41	0.58	1.7	1.41	0.89	0.11	0.98	11.31
Site Type: Alfalfa	Total Alfalfa ETr "	3.95	3.35	4.51	7.73	9.54	10.76	12.05	8.58	6	4.65	3.88	2.64	77.64
Total Growing Degee Days from March 1		0	0	87	278	422	606	745	652	341	193	119	35	3478
Gross Pond Evap	Total "	3.32	2.81	3.79	6.49	8.01	9.04	10.12	7.21	5.04	3.91	3.26	2.22	65.22
Net Pond Evap	Total "	2.81	2.52	3.19	5.71	7.23	8.05	9.72	6.02	4.05	3.28	3.18	1.53	57.29
Crook	Avg. Temp ° F	34.96	27.78	36.82	51.66	59.17	71.94	75.59	71.06	55.91	45.62	35.29	27.61	49.45
Ref date as of 12/31/2006	Total Precip "	0.42	0.24	0.45	0.53	1.06	0.97	0.49	1.47	0.54	0.62	0.05	0.3	7.14
Site Type: Alfalfa	Total Alfalfa ETr "	3.9	3.31	4.19	7.22	8.12	9.79	9.52	7.4	5.18	4.26	3.5	2.2	68.59
Total Growing Degee Days from March 1		0	0	90	281	400	567	683	614	339	210	124	36	3344
Gross Pond Evap	Inch	3.28	2.78	3.52	6.06	6.82	8.22	8	6.22	4.35	3.58	2.94	1.85	57.62
Net Pond Evap	Inch	2.98	2.61	3.2	5.69	6.08	7.54	7.65	5.19	3.97	3.14	2.91	1.64	52.6
Sterling	Avg. Temp ° F	34.25	28.11	37.72	51.72	59.9	72.38	75.53	71.06	56.22	45.76	35.74	26.09	49.54
Ref date as of 12/31/2006	Total Precip "	0.11	0.08	0.48	0.57	0.64	0.72	2.82	3.05	0.68	0.75	0.19	0.67	10.76
Site Type: Alfalfa	Total Alfalfa ETr "	4.1	3.67	4.96	7.82	8.81	10.65	9.78	7.88	5.51	4.32	3.4	2.12	73.02
Total Growing Degee Days from March 1		0	0	112	296	401	582	692	634	344	221	123	33	3438
Gross Pond Evap	Inch	3.44	3.08	4.17	6.57	7.4	8.95	8.22	6.62	4.63	3.63	2.86	1.78	61.35
Net Pond Evap	Inch	3.37	3.03	3.83	6.17	6.95	8.44	6.24	4.48	4.15	3.1	2.72	1.31	53.79
Brush	Avg. Temp ° F	34.29	29.16	38.42	52.17	60.24	72.8	75.55	71.55	56.78	46.67	36.48	25.92	50
Ref date as of 12/31/2006	Total Precip "	0.02	0.01	0.53	0.41	0.84	0.36	1.87	0.44	0.91	0.63	0.06	0.24	6.32
Site Type: Alfalfa	Total Alfalfa ETr "	3.83	3.64	5.1	8.04	8.78	10.91	9.3	8.06	5.16	4.19	3.21	1.96	72.18
Total Growing Degee Days from March 1		0	0	125	304	415	595	705	641	351	238	120	28	3522
Gross Pond Evap	Inch	3.22	3.06	4.28	6.75	7.38	9.16	7.81	6.77	4.33	3.52	2.7	1.65	60.63
Net Pond Evap	Inch	3.2	3.05	3.91	6.47	6.79	8.91	6.5	6.46	3.7	3.08	2.65	1.48	56.2
Fort Morgan	Avg. Temp ° F	34.11	29.02	37.65	51.86	60.23	72.47	75.46	71.52	57.06	46.48	36.2	25.65	49.81
Ref date as of 12/31/2006	Total Precip "	0.1	0.09	1.46	0.49	1.58	0.53	2.35	1.35	1.12	0.87	0.17	0.45	10.56
Site Type: Turf	Total Alfalfa ETr "	3.45	3.29	4.59	7.34	8.48	9.83	9.15	7.7	5.24	3.95	2.83	1.68	67.53
Total Growing Degee Days from March 1		0	0	116	288	409	590	709	647	353	231	101	19	3463
Gross Pond Evap	Inch	2.9	2.76	3.86	6.17	7.12	8.26	7.69	6.47	4.4	3.32	2.38	1.41	56.74
Net Pond Evap	Inch	2.83	2.7	2.83	5.82	6.02	7.89	6.04	5.52	3.62	2.71	2.26	1.1	49.34
Wiggins	Avg. Temp ° F	33.13	28	36.59	50.93	59.15	72.09	74.63	70.15	56.6	45.77	34.92	24.59	48.88
Ref date as of 12/31/2006	Total Precip "	0.08	0.07	0.7	0.44	0.45	0.11	1.7	0.55	0.53	0.42	0.05	0.29	5.39
Site Type: Alfalfa	Total Alfalfa ETr "	3.57	3.26	5	7.89	8.27	10.88	9.95	7.98	5.9	4.29	3.04	1.75	71.78
Total Growing Degee Days from March 1		0	0	111	285	397	580	685	615	354	220	100	19	3366
Gross Pond Evap	Inch	3	2.74	4.2	6.63	6.95	9.14	8.36	6.7	4.96	3.6	2.55	1.47	60.3
Net Pond Evap	Inch	2.94	2.69	3.71	6.32	6.63	9.06	7.17	6.32	4.59	3.31	2.52	1.27	56.53
Fort Collins East	Avg. Temp ° F	34.87	28.7	35.82	50.61	58.57	70	72.26	68.12	55.42	45.02	35.21	25.85	48.37
Ref date as of 12/31/2006	Total Precip "	0.1	0.37	0.93	0.37	0.79	0.15	0.78	0.44	0.83	1.28	0.25	0.57	6.86
Site Type: Alfalfa	Total Alfalfa ETr "	4.07	3.4	4.36	7.85	7.92	9.8	8.12	7.06	5.36	3.8	2.95	1.88	66.57
Total Growing Degee Days from March 1		0	0	87	270	365	539	620	556	324	192	93	18	3064
Gross Pond Evap	Inch	3.42	2.86	3.66	6.59	6.65	8.23	6.82	5.93	4.5	3.19	2.48	1.58	55.91
Net Pond Evap	Inch	3.35	2.6	3.01	6.34	6.1	8.13	6.27	5.62	3.92	2.3	2.3	1.18	51.12
Eaton	Avg. Temp ° F	33.87	28	35.99	50.32	58.38	70.46	72.81	68.17	55.59	45.11	35.05	26.12	48.32
Ref date as of 12/31/2006	Total Precip "	0.05	0.26	0.89	0.29	0.66	0.27	1.29	0.34	0.71	0.67	0.31	0.37	6.11
Site Type: Alfalfa	Total Alfalfa ETr "	3.94	3.39	4.53	8.05	7.96	10.81	8.87	7.38	5.47	3.93	3	1.72	69.05
Total Growing Degee Days from March 1		0	0	96	270	366	550	642	559	327	196	92	17	3115
Gross Pond Evap	Inch	3.31	2.85	3.81	6.76	6.69	9.08	7.45	6.2	4.59	3.3	2.52	1.44	58
Net Pond Evap	Inch	3.27	2.67	3.18	6.56	6.22	8.89	6.55	5.96	4.1	2.83	2.3	1.19	53.72
Johnsons Corner	Avg. Temp ° F	36.38	29.72	37.01	51.85	59.3	71.56	73.52	69.16	56.87	46.9	37.88	28.56	49.89
Ref date as of 12/31/2006	Total Precip "	0.09	0.31	0.79	0.26	0.74	0.13	2.12	1.59	0.36	1.43	0.39	1.36	9.57
Site Type: Alfalfa	Total Alfalfa ETr "	4.01	3.29	4.36	7.71	8.12	10.5	9.11	7.26	5.24	3.98	3	1.89	68.47
Total Growing Degee Days from March 1		0	0	95	274	380	569	668	593	333	203	113	25	3253
Gross Pond Evap	Inch	3.37	2.76	3.66	6.48	6.82	8.82	7.65	6.1	4.4	3.34	2.52	1.59	57.51
Net Pond Evap	Inch	3.31	2.55	3.11	6.29	6.3	8.73	6.17	4.99	4.15	2.34	2.25	0.64	50.83
Gilcrest	Avg. Temp ° F	34.36	27.96	36.76	50.87	58.84	71.46	73.32	69.76	56.23	46	35.2	23.53	48.69
Ref date as of 12/31/2006	Total Precip "	0.08	0.05	0.72	0.42	0.48	0.11	2	1.17	0.35	1.44	0.13	0.21	7.16
Site Type: Alfalfa	Total Alfalfa ETr "	3.46	2.97	4.08	6.76	6.95	9.64	8.06	6.97	4.8	3.42	2.38	1.16	60.65
Total Growing Degee Days from March 1		0	0	104	276	381	567	673	614	347	208	97	10	3277
Gross Pond Evap	Inch	2.91	2.49	3.43	5.68	5.84	8.1	6.77	5.85	4.03	2.87	2	0.97	50.94
Net Pond Evap	Inch	2.85	2.46	2.92	5.38	5.5	8.02	5.37	5.04	3.79	1.86	1.91	0.83	45.93
Longmont South	Avg. Temp ° F	38.84	31.78	38.23	52.91	60.3	71.63	73.89	69.46	56.93	48.07	39.37	30.09	50.96
Ref date as of 12/31/2006	Total Precip "	0.26	0.3	1	0.42	0.63	0.27	2.25	0.68	0.66	2.43	0.5	1.07	10.47
Site Type: Alfalfa	Total Alfalfa ETr "	4.51	3.68	4.48	7.81	7.91	9.75	8.8	7.09	5.37	4.13	3.37	2.11	69.01
Total Growing Degee Days from March 1		0	0	105	284	389	567	669	597	334	213	113	32	3303
Gross Pond Evap	Inch	3.79	3.09	3.76	6.56	6.64	8.19	7.39	5.96	4.51	3.47	2.83	1.77	57.96
Net Pond Evap	Inch	3.61	2.88	3.06	6.27	6.2	8	5.82	5.48	4.05	1.77	2.48	1.02	50.64
Fort Collins NW	Avg. Temp ° F	32.14	25.12	32.01	45	51.77	63.67	67.48	62.67	49.75	39.73	32.47	23.96	43.81
Ref date as of 12/31/2006	Total Precip "	0.08	0.06	0.78	0.21	0.86	0.26	0.8	1.1	0.59	1.84	0.31	0.11	7
Site Type: Turf	Total Alfalfa ETr "	3.39	2.74	3.6	6.96	7.51	9.28	8.18	6.94	4.68	3.1	2.4	1.55	60.33
Total Growing Degee Days from March 1		0	0	78	259	379	555	650	583	317	183	94	24	3122
Gross Pond Evap	Inch	2.85	2.3	3.02	5.85	6.31	7.8	6.87	5.83	3.93	2.6	2.02	1.3	50.68
Net Pond Evap	Inch	2.79	2.26	2.48	5.7	5.71	7.61	6.31	5.06	3.52	1.32	1.8	1.23	45.79
Fort Collins Central	Avg. Temp ° F	36.68	30.4	37.51	52.09	60	70.98	74.1	69.86	56.62	46.43	37.7	28.92	50.11
Ref date as of 12/31/2006	Total Precip "	0.09	0.2	0.81	0.22	0.84	0.16	0.82	1.35	0.58	2.13	0.37	0.37	7.94
Site Type: Turf	Total Alfalfa ETr "	3.55	2.94	3.89	6.85	7.31	8.71	7.71	6.75	4.61	3.17	2.58	1.75	59.82
Total Growing Degee Days from March 1		0	0	91	269	384	561	666	601	333	205	112	33	3255
Gross Pond Evap	Inch	2.98	2.47	3.27	5.75	6.14	7.32	6.48	5.67	3.87	2.66	2.17	1.47	50.25
Net Pond Evap	Inch	2.92	2.33	2.7	5.6	5.55	7.2	5.9	4.73	3.47	1.17	1.91	1.21	44.69
Windsor	Avg. Temp ° F	23.57	0	2.66	45.91	53.55	64.94	68.47	64.87	51.8	41.49	32.98	24.75	39.58
Ref date as of 12/31/2006	Total Precip "	0.06	0	0	0.14	0.56	0.19	1.09	0.58	0.25	1.79	0.36	1.23	6.25
Site Type: Dryland Pasture	Total Alfalfa ETr "	3.09	0	0	0	4.47	10.5	9.06	7.96	5.35	3.74	2.75	1.48	48.4
Total Growing Degee Days from March 1		0	0	14	301	424	601	696	646	374	215	102	23	3396
Gross Pond Evap	Inch	2.6	0	0	0	3.75	8.82	7.61	6.69	4.49	3.14	2.31	1.24	40.65
Net Pond Evap	Inch	2.55	0	0	0	3.36	8.69	6.85	6.28	4.32	1.89	2.06	0.38	36.38
Greeley West	Avg. Temp ° F	35.26	29.15	37.13	51.89	60.61	72.63	75.26	71.02	57.82	46.75	36.4	26.55	50.04
Ref date as of 12/31/2006	Total Precip "	0.01	0.07	0.68	0.33	0.43	0.15	1.85	0.96	0.56	1.43	0.15	0.3	6.92
Site Type: Turf	Total Alfalfa ETr "	3.03	2.73	3.92	6.8	7.58	9.8	8.61	7.39	4.98	3.28	2.16	1.22	61.5
Total Growing Degee Days from March 1		0	0	95	279	404	605	702	638	354	208	89	20	3394
Gross Pond Evap	Inch	2.55	2.29	3.29	5.71	6.37	8.23	7.23	6.21	4.18	2.76	1.81	1.02	51.65
Net Pond Evap	Inch	2.54	2.24	2.82	5.48	6.07	8.13	5.94	5.54	3.79	1.75	1.71	0.81	46.82
Loveland	Avg. Temp ° F	36.77	30.23	37.29	52.3	60.2	71.4	74.24	70.26	57.25	46.86	37.81	28.82	50.29
Ref date as of 12/31/2006	Total Precip "	0.07	0.09	0.83	0.15	0.59	0.15	1.64	1.59	0.25	2.02	0.28	0.29	7.95
Site Type: Turf	Total Alfalfa ETr "	3.03	2.57	3.62	6.45	7.05	8.53	7.57	6.48	4.41	2.86	2.03	1.28	55.88
Total Growing Degee Days from March 1		0	0	91	266	388	584	687	625	336	196	95	28	3296
Gross Pond Evap	Inch	2.55	2.16	3.04	5.42	5.92	7.17	6.36	5.44	3.7	2.4	1.71	1.08	46.95
Net Pond Evap	Inch	2.5	2.1	2.46	5.31	5.51	7.06	5.21	4.33	3.53	0.99	1.51	0.87	41.38
Berthoud	Avg. Temp ° F	37.28	29.89	37.13	52.23	60.16	71.7	74.26	70.07	57.51	47.41	38.16	29.68	50.46
Ref date as of 12/31/2006	Total Precip "	0.09	0.41	0.94	0.19	0.89	0.17	2.33	0.88	0.77	2.01	0.41	1.28	10.37
Site Type: Turf	Total Alfalfa ETr "	3.91	3.12	4.19	7.59	8.42	10.19	9.14	7.62	5.64	4.01	2.89	2.08	68.8
Total Growing Degee Days from March 1		0	0	88	266	383	586	691	613	325	194	97	25	3268
Gross Pond Evap	Inch	3.28	2.62	3.52	6.38	7.07	8.56	7.68	6.4	4.74	3.37	2.43	1.75	57.8
Net Pond Evap	Inch	3.22	2.33	2.86	6.24	6.45	8.44	6.05	5.78	4.2	1.96	2.14	0.85	50.52
Longmont West	Avg. Temp ° F	38.39	31.32	38.32	53.44	60.98	72.39	74.6	70.88	57.82	48.12	39.39	30.64	51.36
Ref date as of 12/31/2006	Total Precip "	0.14	0.05	0.82	0.25	0.82	0.34	2.9	1.51	0.6	2.31	0.24	0.65	10.63
Site Type: Turf	Total Alfalfa ETr "	2.54	2.35	3.45	6.08	6.84	8.16	7.38	6.3	4.31	2.92	2.11	1.44	53.88
Total Growing Degee Days from March 1		0	0	93	281	402	610	709	640	340	209	113	33	3430
Gross Pond Evap	Inch	2.13	1.97	2.9	5.11	5.75	6.85	6.2	5.29	3.62	2.45	1.77	1.21	45.25
Net Pond Evap	Inch	2.04	1.94	2.32	4.93	5.17	6.62	4.17	4.24	3.2	0.84	1.6	0.75	37.82
Fort Lupton	Avg. Temp ° F	36.8	29.57	37.07	51.54	59.99	71.83	74.35	70.44	57.1	47.28	37.96	28.18	50.18
Ref date as of 12/31/2006	Total Precip "	0.12	0.08	1.11	1.72	1.95	1.45	3.23	2.34	0.44	1.04	0.13	0.21	13.82
Site Type: Turf	Total Alfalfa ETr "	4.07	3.66	4.61	7.61	8.91	10.91	9.72	8.51	6.03	4.6	3.33	2.16	74.12
Total Growing Degee Days from March 1		0	0	103	272	394	587	690	631	352	221	113	36	3399
Gross Pond Evap	Inch	3.42	3.07	3.87	6.39	7.48	9.16	8.16	7.15	5.07	3.86	2.8	1.81	62.24
Net Pond Evap	Inch	3.33	3.02	3.1	5.19	6.12	8.15	5.9	5.51	4.76	3.14	2.71	1.67	52.6
Boulder NW	Avg. Temp ° F	39.63	32.63	37.63	52.97	61.2	72.46	74.6	70.87	57.52	49.02	41.47	33.71	51.98
Ref date as of 12/31/2006	Total Precip "	0.31	0.32	1.22	0.78	0.78	2	2.31	0.85	0.63	2.34	0.34	0.79	12.67
Site Type: Turf	Total Alfalfa ETr "	4.06	3.28	3.9	7.08	8.19	9.35	8.9	7.48	5.24	4.01	3.34	2.17	67
Total Growing Degee Days from March 1		0	0	97	286	413	589	684	630	346	215	119	40	3419
Gross Pond Evap	Inch	3.41	2.76	3.28	5.95	6.88	7.85	7.48	6.28	4.4	3.37	2.81	1.82	56.29
Net Pond Evap	Inch	3.19	2.53	2.42	5.4	6.33	6.45	5.86	5.69	3.96	1.73	2.57	1.27	47.4
Boulder East	Avg. Temp ° F	40.1	33.03	38.79	54.45	62.5	73.96	76.17	72.4	58.74	49.83	41.87	33.05	52.91
Ref date as of 12/31/2006	Total Precip "	0.22	0.15	1.17	0.62	0.7	1.02	2	0.65	0.59	3.2	0.1	0.92	11.34
Site Type: Turf	Total Alfalfa ETr "	3.81	3.3	3.99	7.08	8.11	9.31	8.28	7.1	4.92	3.69	2.98	1.62	64.19
Total Growing Degee Days from March 1		0	0	94	282	417	619	719	663	345	219	118	44	3520
Gross Pond Evap	Inch	3.2	2.77	3.35	5.95	6.81	7.82	6.96	5.96	4.13	3.1	2.5	1.36	53.91
Net Pond Evap	Inch	3.05	2.67	2.53	5.51	6.32	7.11	5.56	5.51	3.72	0.86	2.43	0.72	45.99
Boulder Flatiron	Avg. Temp ° F	38.11	31.59	37.18	51.84	59.39	69.64	72.15	68.53	55.33	47.32	39.2	30.69	50.08
Ref date as of 12/31/2006	Total Precip "	0.21	0.04	0.83	0.66	0.63	0.79	2.19	0.65	0.57	3.09	0.08	0.43	10.17
Site Type: Turf	Total Alfalfa ETr "	3.05	2.76	3.55	5.96	6.36	7.03	6.15	5.03	3.76	2.66	2.34	1.49	50.14
Total Growing Degee Days from March 1		0	0	92	261	378	526	634	578	327	203	113	40	3152
Gross Pond Evap	Inch	2.56	2.32	2.98	5.01	5.34	5.91	5.17	4.23	3.16	2.23	1.97	1.25	42.13
Net Pond Evap	Inch	2.42	2.29	2.4	4.54	4.9	5.35	3.63	3.77	2.76	0.07	1.91	0.95	34.99
Boulder SW	Avg. Temp ° F	41.42	34.07	38.37	53.29	60.69	71.63	74.26	70.45	58.05	49.95	42.88	35.79	52.57
Ref date as of 12/31/2006	Total Precip "	0.18	0.04	1.18	1.01	0.76	1.29	2.65	1.39	0.86	2.91	0.19	0.82	13.28
Site Type: Turf	Total Alfalfa ETr "	4.85	3.88	4.24	7.31	8.13	9.15	8.25	7.02	5.21	4.27	3.8	2.85	68.96
Total Growing Degee Days from March 1		0	0	75	248	380	579	693	607	310	199	105	41	3237
Gross Pond Evap	Inch	4.07	3.26	3.56	6.14	6.83	7.69	6.93	5.9	4.38	3.59	3.19	2.39	57.93
Net Pond Evap	Inch	3.95	3.23	2.74	5.43	6.3	6.78	5.08	4.92	3.77	1.55	3.06	1.82	48.63