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	2008	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	or Avg.
Ovid	Avg. Temp ° F	23.45	30.6	38.7	46.39	55.78	66.6	75.32	70.15	60.46	49.08	39.21	23.48	48.27
Ref date as of 12/31/2008	Total Precip "	0.03	0.12	0.59	2.15	3.12	2.97	3.77	3.3	1.75	1.92	0.47	0.34	20.53
Site Type: Alfalfa	Total Alfalfa ETr "	2	3.14	5.41	6.98	7.56	9.43	10.15	7.63	5.86	4.6	3.52	2.45	68.73
Total Growing Degee Days from March 1		0	0	99	195	310	497	694	609	408	266	118	33	3229
Gross Pond Evap	Total "	1.68	2.64	4.54	5.86	6.35	7.92	8.53	6.41	4.92	3.86	2.96	2.06	57.73
Net Pond Evap	Total "	1.66	2.55	4.13	4.36	4.17	5.84	5.89	4.1	3.7	2.52	2.63	1.82	43.37
Crook	Avg. Temp ° F	22.06	30.62	38.77	46.81	55.63	66.13	73.64	69.79	59.51	48.63	38.9	21.99	47.71
Ref date as of 12/31/2008	Total Precip "	0.05	0.18	0.56	1.18	2.23	1.09	4.71	2.4	1.24	1.05	0.63	0.22	15.54
Site Type: Alfalfa	Total Alfalfa ETr "	1.77	2.98	5.36	7.18	7.04	8.88	8.97	7.73	5.58	5.04	3.86	2.34	66.73
Total Growing Degee Days from March 1		0	0	105	200	309	477	667	607	387	257	110	27	3146
Gross Pond Evap	Inch	1.49	2.5	4.5	6.03	5.91	7.46	7.53	6.49	4.69	4.23	3.24	1.97	56.04
Net Pond Evap	Inch	1.45	2.38	4.11	5.21	4.35	6.7	4.24	4.81	3.82	3.5	2.8	1.81	45.18
Sterling	Avg. Temp ° F	19.85	30.16	38.96	46.5	56.1	66.56	74.59	69.29	60.34	48.74	38.89	21.8	47.65
Ref date as of 12/31/2008	Total Precip "	0.13	0.26	0.44	0.82	0.61	1.3	2.09	3.72	0.96	0.72	0.63	0.3	11.98
Site Type: Alfalfa	Total Alfalfa ETr "	1.46	2.53	5.33	7.28	8.06	9.53	10.33	7.71	6.43	5.04	3.61	2.09	69.4
Total Growing Degee Days from March 1		0	0	107	203	335	484	662	582	410	271	123	30	3207
Gross Pond Evap	Inch	1.23	2.13	4.48	6.12	6.77	8.01	8.68	6.48	5.4	4.23	3.03	1.76	58.32
Net Pond Evap	Inch	1.14	1.94	4.17	5.54	6.34	7.1	7.21	3.87	4.73	3.73	2.59	1.55	49.91
Brush	Avg. Temp ° F	18.8	30.36	39.89	46.97	56.59	66.52	74.73	69.32	59.96	49.25	39.04	21.23	47.72
Ref date as of 12/31/2008	Total Precip "	0.1	0.13	0.17	0.4	1.32	2.93	2.02	3.06	1.04	0.3	0.27	0.27	12.01
Site Type: Alfalfa	Total Alfalfa ETr "	1.51	2.47	5.38	7.18	7.81	8.9	10.29	7.51	5.7	5.22	3.71	1.85	67.53
Total Growing Degee Days from March 1		0	0	113	200	350	484	685	592	399	279	134	22	3258
Gross Pond Evap	Inch	1.27	2.07	4.52	6.03	6.56	7.48	8.64	6.31	4.79	4.38	3.12	1.55	56.72
Net Pond Evap	Inch	1.2	1.98	4.4	5.75	5.64	5.43	7.23	4.17	4.06	4.17	2.93	1.37	48.33
Fort Morgan	Avg. Temp ° F	19.45	30.48	39.58	47.2	57.08	66.83	75.22	69.54	60.26	49.16	39.21	21.51	47.96
Ref date as of 12/31/2008	Total Precip "	0.21	0.23	0.31	0.92	1.5	1.59	2.67	6.02	1.43	0.52	0.47	0.48	16.35
Site Type: Turf	Total Alfalfa ETr "	1.42	2.37	4.93	6.88	7.74	8.82	10	7.34	5.59	4.69	3.5	1.7	64.98
Total Growing Degee Days from March 1		0	0	107	203	349	491	684	598	400	265	126	21	3244
Gross Pond Evap	Inch	1.19	1.99	4.14	5.78	6.5	7.41	8.4	6.17	4.7	3.94	2.94	1.43	54.59
Net Pond Evap	Inch	1.05	1.83	3.92	5.14	5.45	6.3	6.53	1.95	3.69	3.58	2.61	1.09	43.14
Wiggins	Avg. Temp ° F	18.18	30.51	39.34	46.69	56.47	67.25	75.07	69.13	59.77	48.79	38.68	19.98	47.49
Ref date as of 12/31/2008	Total Precip "	0.14	0.15	0.33	0.69	0.99	0.58	2.03	2.41	1.56	0.6	0.21	0.25	9.94
Site Type: Alfalfa	Total Alfalfa ETr "	1.46	2.57	5.4	7.47	8.16	10.19	11.11	7.92	5.79	4.27	3.62	1.65	69.61
Total Growing Degee Days from March 1		0	0	109	198	336	501	680	578	386	258	133	19	3198
Gross Pond Evap	Inch	1.23	2.16	4.54	6.27	6.85	8.56	9.33	6.65	4.86	3.59	3.04	1.39	58.47
Net Pond Evap	Inch	1.13	2.05	4.31	5.79	6.16	8.15	7.91	4.97	3.77	3.17	2.89	1.21	51.51
Fort Collins East	Avg. Temp ° F	24.34	32.31	38.39	45.65	54.86	64.76	71.84	66.68	57.35	47.65	40.09	23.86	47.32
Ref date as of 12/31/2008	Total Precip "	0	0.06	0.71	1.73	1.96	1.97	0.43	4.06	1.09	0.5	0.05	0.26	12.82
Site Type: Alfalfa	Total Alfalfa ETr "	2.19	3.57	5.26	7.07	7.53	8.87	8.9	6.66	4.96	4.48	3.89	2.22	65.6
Total Growing Degee Days from March 1		0	0	87	175	302	452	616	511	336	234	123	29	2865
Gross Pond Evap	Inch	1.84	3	4.42	5.94	6.33	7.45	7.48	5.59	4.17	3.76	3.27	1.86	55.11
Net Pond Evap	Inch	1.84	2.96	3.92	4.73	4.95	6.07	7.18	2.75	3.4	3.41	3.23	1.68	46.12
Eaton	Avg. Temp ° F	22.36	31.59	38.36	45.93	55.51	65.09	71.65	65.99	57.46	47.01	38.61	22.4	46.83
Ref date as of 12/31/2008	Total Precip "	0.04	0.13	0.59	0.53	1.13	1.78	0.56	4.09	1.98	0.8	0.17	0.26	12.06
Site Type: Alfalfa	Total Alfalfa ETr "	1.88	3.31	5.42	7.36	7.75	8.51	8.57	6.23	5.03	4.09	3.47	1.86	63.48
Total Growing Degee Days from March 1		0	0	93	184	313	459	620	510	349	233	124	23	2908
Gross Pond Evap	Inch	1.58	2.78	4.55	6.18	6.51	7.15	7.2	5.23	4.23	3.44	2.91	1.56	53.32
Net Pond Evap	Inch	1.55	2.69	4.14	5.81	5.72	5.9	6.81	2.37	2.84	2.88	2.8	1.38	44.89
Johnsons Corner	Avg. Temp ° F	24.29	33.53	39.29	46.54	55.78	65.76	74.24	67.77	58.94	49.29	41.26	24.45	48.43
Ref date as of 12/31/2008	Total Precip "	0.11	0.29	0.79	0.7	1.95	1.3	1.15	2.72	1.47	0.54	0.24	0.48	11.74
Site Type: Alfalfa	Total Alfalfa ETr "	1.82	3.15	4.95	6.69	7.34	8.77	9.75	7.01	5.06	4.06	3.17	2.16	63.93
Total Growing Degee Days from March 1		0	0	93	184	315	476	653	544	358	230	127	30	3010
Gross Pond Evap	Inch	1.53	2.65	4.16	5.62	6.17	7.37	8.19	5.89	4.25	3.41	2.66	1.81	53.71
Net Pond Evap	Inch	1.45	2.44	3.61	5.13	4.8	6.46	7.39	3.98	3.22	3.03	2.49	1.48	45.48
Gilcrest	Avg. Temp ° F	19.53	32.07	38.93	46.33	55.98	65.84	73.53	67.36	58.6	47.19	38.17	20.69	47.02
Ref date as of 12/31/2008	Total Precip "	0.05	0.26	0.57	0.6	2.17	1.28	0.36	4.8	1.66	2.16	0.17	0.34	14.42
Site Type: Alfalfa	Total Alfalfa ETr "	1.46	2.86	4.93	7.05	7.03	8.83	9.57	6.86	5.14	3.84	3	1.73	62.3
Total Growing Degee Days from March 1		0	0	100	202	323	477	644	532	386	247	139	25	3075
Gross Pond Evap	Inch	1.23	2.4	4.14	5.92	5.91	7.42	8.04	5.76	4.32	3.23	2.52	1.45	52.34
Net Pond Evap	Inch	1.19	2.22	3.74	5.5	4.39	6.52	7.79	2.4	3.16	1.71	2.4	1.22	42.24
Longmont South	Avg. Temp ° F	27.16	34.1	40.02	47.17	56.25	66.27	73.93	67.82	59.32	49.57	42.36	26.87	49.24
Ref date as of 12/31/2008	Total Precip "	0.13	0.32	0.79	0.52	2.14	1.25	0.04	2.36	1.54	0.35	0.35	0.59	10.38
Site Type: Alfalfa	Total Alfalfa ETr "	2.59	3.37	5.28	6.86	7.14	9.25	9.7	7.12	5.41	4.41	3.7	2.52	67.35
Total Growing Degee Days from March 1		0	0	96	192	324	478	638	536	359	242	140	42	3047
Gross Pond Evap	Inch	2.18	2.83	4.44	5.76	6	7.77	8.15	5.98	4.54	3.7	3.11	2.12	56.58
Net Pond Evap	Inch	2.08	2.61	3.88	5.4	4.5	6.9	8.12	4.33	3.47	3.46	2.86	1.7	49.31
Fort Collins NW	Avg. Temp ° F	25.18	32.98	38.56	46.17	56.02	65.92	74.14	67.73	58.88	48.57	40.98	24.96	48.34
Ref date as of 12/31/2008	Total Precip "	0.03	0.14	0.76	0.6	1.38	1.66	1.25	3.2	1.01	0.59	0.03	0.31	10.96
Site Type: Turf	Total Alfalfa ETr "	1.81	2.79	3.4	4.88	5.73	6.77	6.77	4.81	3.64	2.69	2.76	1.75	47.8
Total Growing Degee Days from March 1		0	0	96	198	332	486	642	541	394	252	118	25	3084
Gross Pond Evap	Inch	1.52	2.34	2.86	4.1	4.81	5.69	5.69	4.04	3.06	2.26	2.32	1.47	40.16
Net Pond Evap	Inch	1.5	2.25	2.32	3.68	3.85	4.52	4.81	1.8	2.35	1.85	2.3	1.25	32.48
Fort Collins Central	Avg. Temp ° F	26.18	33.83	39.32	47.05	56.07	66.25	73.68	67.74	58.8	48.97	41.87	26.15	48.83
Ref date as of 12/31/2008	Total Precip "	0.01	0.17	0.77	0.73	1.54	1.96	0.63	4.17	1.27	0.68	0.05	0.29	12.27
Site Type: Turf	Total Alfalfa ETr "	2.18	3.12	4.53	6.49	6.79	8.13	8.38	5.72	4.28	3.3	2.85	1.87	57.64
Total Growing Degee Days from March 1		0	0	92	189	319	477	640	539	367	253	150	39	3065
Gross Pond Evap	Inch	1.83	2.62	3.81	5.45	5.7	6.83	7.04	4.8	3.6	2.77	2.39	1.57	48.41
Net Pond Evap	Inch	1.82	2.5	3.27	4.94	4.63	5.46	6.6	1.89	2.71	2.3	2.36	1.37	39.85
Windsor	Avg. Temp ° F	24.39	33.47	39.63	47.41	57.03	67.19	75.63	68.87	59.98	49.78	41.47	24.08	49.08
Ref date as of 12/31/2008	Total Precip "	0.09	0.26	0.56	0.84	2.04	1.25	0.43	0.93	1.23	0.93	0.08	0.28	8.92
Site Type: Dryland Pasture	Total Alfalfa ETr "	1.7	2.8	4.54	6.46	7.07	8.23	8.95	6.53	4.76	3.63	2.84	1.52	59.03
Total Growing Degee Days from March 1		0	0	105	211	356	511	676	576	389	258	137	26	3245
Gross Pond Evap	Inch	1.43	2.35	3.81	5.43	5.94	6.91	7.52	5.49	4	3.05	2.39	1.28	49.6
Net Pond Evap	Inch	1.37	2.17	3.42	4.84	4.51	6.04	7.22	4.83	3.14	2.4	2.33	1.08	43.35
Greeley West	Avg. Temp ° F	22.45	32.4	39.26	46.54	56.17	66.17	74.32	67.76	58.88	48.31	39.35	22.23	47.82
Ref date as of 12/31/2008	Total Precip "	0.05	0.16	0.61	0.52	1.22	1.91	1.72	6.3	1.9	0.57	0.18	0.22	15.36
Site Type: Turf	Total Alfalfa ETr "	1.46	2.79	4.66	6.67	7.48	8.58	9.28	6.74	5.08	3.74	2.8	1.45	60.73
Total Growing Degee Days from March 1		0	0	95	188	329	485	669	555	368	231	113	17	3050
Gross Pond Evap	Inch	1.23	2.34	3.91	5.6	6.28	7.21	7.8	5.66	4.27	3.14	2.35	1.22	51.01
Net Pond Evap	Inch	1.19	2.23	3.49	5.24	5.43	5.87	6.59	1.25	2.94	2.74	2.23	1.06	40.26
Loveland	Avg. Temp ° F	26.15	33.55	39.2	47.23	56.32	66.19	74.33	68.76	59.91	49.44	41.5	25.77	49.03
Ref date as of 12/31/2008	Total Precip "	0.01	0.2	0.82	0.52	1.86	1.02	0.35	2.4	1.4	0.66	0.04	0.39	9.67
Site Type: Turf	Total Alfalfa ETr "	2.02	2.87	4.55	6.43	6.89	8.14	8.17	5.97	4.51	3.17	2.28	1.6	56.6
Total Growing Degee Days from March 1		0	0	84	186	314	486	679	579	381	240	137	36	3122
Gross Pond Evap	Inch	1.7	2.41	3.82	5.4	5.79	6.84	6.86	5.01	3.79	2.66	1.92	1.34	47.54
Net Pond Evap	Inch	1.69	2.27	3.25	5.04	4.49	6.12	6.62	3.33	2.81	2.2	1.89	1.07	40.78
Berthoud	Avg. Temp ° F	24.58	32.85	38.58	46.11	55.3	65.56	73.9	67.64	59.13	49.1	41.49	25.13	48.28
Ref date as of 12/31/2008	Total Precip "	0.06	0.3	1.06	0.62	2.98	1.5	1.07	4.11	1.86	0.52	0.24	0.37	14.69
Site Type: Turf	Total Alfalfa ETr "	1.89	3.11	4.82	6.58	7.29	9.09	9.84	7.28	5.46	4.09	3.33	1.98	64.76
Total Growing Degee Days from March 1		0	0	81	174	298	468	667	538	340	214	134	27	2941
Gross Pond Evap	Inch	1.59	2.61	4.05	5.53	6.12	7.64	8.27	6.12	4.59	3.44	2.8	1.66	54.42
Net Pond Evap	Inch	1.55	2.4	3.31	5.09	4.04	6.59	7.52	3.24	3.28	3.07	2.63	1.4	44.12
Longmont West	Avg. Temp ° F	27.31	34.49	40.32	47.77	56.82	67.28	75.31	68.84	59.63	48.87	41.59	26.56	49.57
Ref date as of 12/31/2008	Total Precip "	0	0.26	0.6	0.67	2.5	1.33	0.18	3.23	1.61	0.46	0.15	0.22	11.21
Site Type: Turf	Total Alfalfa ETr "	1.74	2.41	3.91	5.67	6.48	7.84	8.18	6.61	4.8	3.29	2.6	1.98	55.51
Total Growing Degee Days from March 1		0	0	92	190	322	507	696	564	368	250	139	40	3168
Gross Pond Evap	Inch	1.46	2.02	3.28	4.76	5.44	6.59	6.87	5.55	4.03	2.76	2.18	1.66	46.6
Net Pond Evap	Inch	1.46	1.84	2.86	4.29	3.69	5.65	6.75	3.29	2.91	2.44	2.08	1.51	38.77
Fort Lupton	Avg. Temp ° F	26.39	34.13	40.39	47.64	56.86	67.39	75.95	69.7	60.7	50.24	41.78	25.52	49.72
Ref date as of 12/31/2008	Total Precip "	0.02	0.21	0.39	0.32	1.94	1.34	0.51	5.23	1.6	0.86	0.18	0.1	12.7
Site Type: Turf	Total Alfalfa ETr "	2.39	3.39	5.22	7.24	7.8	9.96	11.02	8.43	6.32	4.98	3.92	2.19	72.86
Total Growing Degee Days from March 1		0	0	106	202	331	509	698	598	396	273	147	43	3303
Gross Pond Evap	Inch	2.01	2.85	4.38	6.08	6.55	8.37	9.26	7.08	5.31	4.18	3.29	1.84	61.2
Net Pond Evap	Inch	1.99	2.7	4.11	5.86	5.19	7.43	8.9	3.42	4.19	3.58	3.17	1.77	52.31
Boulder NW	Avg. Temp ° F	30.28	34.99	40.01	47.62	56.67	67.21	75.73	69.26	60.26	51.14	44.5	30.82	50.71
Ref date as of 12/31/2008	Total Precip "	0.08	0.43	0.63	0.72	2.05	1.46	0.21	2.29	1.33	1.04	0.15	0.75	11.14
Site Type: Turf	Total Alfalfa ETr "	2.59	3.08	4.72	6.49	7.16	8.88	9.34	7.15	5.22	4.06	3.44	2.68	64.81
Total Growing Degee Days from March 1		0	0	94	198	336	509	683	588	394	261	150	51	3264
Gross Pond Evap	Inch	2.18	2.59	3.96	5.45	6.01	7.46	7.85	6.01	4.38	3.41	2.89	2.25	54.44
Net Pond Evap	Inch	2.12	2.29	3.52	4.95	4.58	6.44	7.7	4.4	3.45	2.68	2.78	1.73	46.64
Boulder East	Avg. Temp ° F	29.76	35.32	41.29	48.77	57.89	68.91	77.91	70.97	61.53	51.35	26.63	30.25	50.05
Ref date as of 12/31/2008	Total Precip "	0.07	0.56	1.94	3.8	2.66	1.35	0.01	3.41	1.6	0.73	0.09	0.44	16.66
Site Type: Turf	Total Alfalfa ETr "	2.7	3.08	4.91	6.6	7.18	8.62	9.03	6.73	4.78	3.49	1.43	2.54	61.09
Total Growing Degee Days from March 1		0	0	90	192	331	523	721	606	383	259	104	52	3261
Gross Pond Evap	Inch	2.27	2.59	4.12	5.54	6.03	7.24	7.59	5.65	4.02	2.93	1.2	2.13	51.31
Net Pond Evap	Inch	2.22	2.2	2.77	2.88	4.17	6.3	7.58	3.27	2.9	2.42	1.14	1.83	39.68
Boulder Flatiron	Avg. Temp ° F	28.62	33.74	39.79	46.56	55.87	65.29	72.32	66.99	58.21	37.32	38.28	29.31	47.69
Ref date as of 12/31/2008	Total Precip "	0.1	0.31	0.64	0.77	3.26	1.36	0.06	3	2.12	0.8	0.09	0.37	12.88
Site Type: Turf	Total Alfalfa ETr "	2.38	2.69	4.2	5.54	5.87	6.61	6.41	4.96	3.6	1.92	1.94	2.12	48.24
Total Growing Degee Days from March 1		0	0	86	186	304	457	616	520	352	164	111	48	2844
Gross Pond Evap	Inch	2	2.26	3.53	4.65	4.93	5.55	5.38	4.17	3.02	1.61	1.63	1.78	40.51
Net Pond Evap	Inch	1.93	2.04	3.08	4.11	2.65	4.6	5.34	2.07	1.54	1.05	1.57	1.52	31.5
Boulder SW	Avg. Temp ° F	32.18	36.7	41.3	48.54	56.96	67.95	76.33	69.61	60.87	52.45	45.97	32.04	51.74
Ref date as of 12/31/2008	Total Precip "	0.07	0.42	0.88	0.87	3.35	1.17	0.03	2.78	1.87	1.01	0.15	0.57	13.17
Site Type: Turf	Total Alfalfa ETr "	3.57	3.49	5.23	6.83	7.29	9.31	9.66	6.76	4.87	4.01	3.83	3.36	68.21
Total Growing Degee Days from March 1		0	0	78	169	307	511	737	583	357	230	138	49	3159
Gross Pond Evap	Inch	3	2.93	4.39	5.74	6.12	7.82	8.11	5.68	4.09	3.37	3.22	2.82	57.29
Net Pond Evap	Inch	2.95	2.64	3.78	5.13	3.78	7	8.09	3.73	2.78	2.66	3.11	2.42	48.07